Modeling and Simulation of a Hybrid System of Solar Panels and Wind Turbines for the Supply of Autonomous Electrical Energy to Organic Architectures

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Article Modeling and Simulation of a Hybrid System of Solar Panels and Wind Turbines for the Supply of Autonomous Electrical Energy to Organic Architectures

1, , 2 1, Daniel Icaza * † , David Borge-Diez , Santiago Pulla Galindo † and Carlos Flores-Vázquez 1

1 GIRVyP Group Reserch, Faculty of Electrical Engineering, Catholic University of Cuenca, Cuenca 010111, Ecuador; [email protected] (S.P.G.); cﬂ[email protected] (C.F.-V.) 2 Department of Electrical, Systems and Automation Engineering, University of Leon, 24007 León, Spain; [email protected] * Correspondence: [email protected] PHD Student at the University of Leon, 24007 León, Spain. † Received: 22 July 2020; Accepted: 25 August 2020; Published: 7 September 2020

Abstract: In this research, the modeling, simulation, and analysis of the energy conversion equations that describe the behavior of a hybrid photovoltaic and wind turbine system that supplies electrical energy to an average organic architecture is performed. Organic constructions have a philosophy that seeks to understand and integrate into the site, taking advantage of the natural potentials and their resources of the surrounding areas so that they form part of a uniﬁed and correlated composition. The rooms in these buildings are designed similar to a bean, inspired by the uterus of a mother and her child who are comfortable, at rest, and alive. We are left with the task of spreading this research to integrate its energy potential from the surroundings and transform it into autonomous electrical energy. In this article, a numerical model based on the fundamental equations was developed and coded, and the results compared with experimental data with a real airplane-type system located in a remote area of Ecuador. The model is intended to be used as an optimization and design tool for such hybrid systems applied to organic constructions. After an error analysis it was determined that this model predicted quite interesting results compared to the experimental data under various conditions. It is important to indicate that this analysis has been carried out so that in the future, these power generation systems can be exploited and applied more eﬃciently in areas far from the public electricity grid.

Keywords: hybrid system; organic constructions; renewable energy; solar panel; wind turbine

1. Introduction The flight of the birds, the shapes of the plants, the color of the flowers, the sprouting of the waters, among other prodigies of nature, were the inspiration for the multiple and revolutionary inventions that have been made so far and that over the years human beings continue to develop for the benefit of the countries and their continents [1]. Organic architecture is a philosophy of architecture that promotes harmony between the human habitat and the natural world. Through design, it seeks to understand and integrate the territory, through real territorial development plans, to small complementary works in public or private spaces [2]. Larger buildings, such as buildings, furniture, housing, and the surroundings, are propitious spaces for them to become part of a unified and correlated composition [3].

Energies 2020, 13, 4649; doi:10.3390/en13184649 www.mdpi.com/journal/energies Energies 2020, 13, 4649 2 of 27 Energies 2020, 13, x FOR PEER REVIEW 2 of 27

Explained inin anotheranother way, way, each each environment environment seeks seeks to make to make it cozy it andcozy pleasant, and pleasant, where where the people the whopeople inhabit who inhabit it really it feel really at homefeel at with home spaces with speciallyspaces specially designed designed and inspired and inspired by mother by mother nature. nature.Figures 1Figures and2 identify 1 and 2 howidentify these how spaces these are spaces perfectly are perfectly designed designed to welcome to welcome the family. the The family. aspects The aspectsrelated torelated natural to lightingnatural lighting are essential, are essential, it is important it is important that thebasic that the services basic for services living for are living available, are available,such as drinking such as water, drinking sewerage, water, sewerage, electricity, electricity, internet, etc. internet, etc.

Figure 1. InternalInternal structure structure based on anti-seismic rods.

Figure 2. Construction that harmonizes with nature.

Taking Figures1 1 and and2 2as as a a reference, reference, it it was was born born from from the the idea idea of of creating creating a a space space adapted adapted to to man according to his environmental, physical and psychological needs, taking into account its origin in nature nature [4]. [4]. As As a aresult result of of these these designs, designs, it insp it inspiresires to create to create different different environments environments according according to the to realitythe reality of each of each locality. locality. Our interestinterest is is focused focused on on the the supply supply of electrical of electr energy,ical energy, a major a limitationmajor limitation when making whenlocations making locationsin rural areas in rural and areas far from and commercialfar from commercial distribution distribution networks. networks. This infrastructure This infrastructure is full of is comfort, full of comfort,but when but we when carry itwe out, carry we it continually out, we continually have difficulty have in difficulty supplying in electricity.supplying Forelectricity. this reason, For this our reason,study seeks our astudy mathematical seeks a mathematical model that is amodel reference thatwhen is a reference making ourwhen developments making our in developments the field. Below, in wethe arefield. immensely Below, we interested are immensely in reviewing interested the in progress reviewing that the has progress been made that inhas related been made infrastructures in related infrastructuresthat are not common that are and not possess common great and gifts possess of innovation great gifts and of innovation are gaining and strength. are gaining strength. 1.1. Review of the Literature 1.1. Review of the Literature There are several developed architectural designs that are related to nature such as the one There are several developed architectural designs that are related to nature such as the one presented by Avila et al. [5], which consists of an interesting development of a tree that produces presented by Avila et al. [5], which consists of an interesting development of a tree that produces shadows with the intention that the people who are under the tree are protected against solar radiation shadows with the intention that the people who are under the tree are protected against solar radiation but at the same time take advantage of this solar radiation to transform it into electrical energy. but at the same time take advantage of this solar radiation to transform it into electrical energy. Another article that refers to designed systems that link natural environments with innovative Another article that refers to designed systems that link natural environments with innovative architectures is that of E. Duque et al. [6] where it is supplied with photovoltaic solar energy. architectures is that of E. Duque et al. [6] where it is supplied with photovoltaic solar energy. Although there are small developments such as those indicated above, they do not at all address Although there are small developments such as those indicated above, they do not at all address organic habitable constructions such as what is intended to be addressed in this article. This type organic habitable constructions such as what is intended to be addressed in this article. This type of organic construction has been developed by architects, but within the literature no developments

Energies 2020, 13, 4649 3 of 27 of organic construction has been developed by architects, but within the literature no developments related to the supply of electrical energy are identified, even knowing that it is a major limitation when putting all basic infrastructure and services into operation. The present investigation has been a motivation of the authors that when seeing the limited literature, we seek to give a point of reference so that they continue progressively addressing this subject, there really is much that can be studied. In our case, we take energy supply from renewable energy sources as a reference, since when considering that these constructions must be located in considerable spaces and that are related to the environment, there is not always available electrical energy supplied by the public electricity network by which is a sufficient reason to provide a contribution. Given that access to commercial electrical distribution networks is not always available, it has been seen that it is necessary to provide us with a distributed electric power system. Distributed generation is known as decentralized or on-site generation and has several benefits including low cost, less complexity, eliminates the interdependencies and inefficiencies associated with transmission and distribution. There are many reasons to use distributed generation, such as standby or emergency generation, as well as backup and the great potential of a green energy source using renewable technology, particularly for the electrification of remote locations disconnected from the grid such which raised Ayodele [7]. Renewable and unconventional methods of energy generation such as wind, solar, hydro, biomass, geothermal, thermal storage, and waste heat recovery are the generations that have radically changed the productive matrix of developed countries and that are currently entering strongly in developing countries. The aforementioned power generation technologies also offer power supply solutions for remote areas, in the case of organic constructions which is the objective of the analysis of this article, it is a certain possibility for autonomous power supply, not accessible by the supply of energy from the public electricity grid [8]. Another recommended aspect is to implement hybrid systems for the generation of electricity using renewable energy sources. There are several experiences in this regard. Maleki A. et al. constructed a model for the optimal operation of a hybrid system for residential applications [9]. Ming, Mengjun, et al. present in reference [10] an algorithm to optimize the energy of a hybrid system (wind and PhotovoltaicPV). Oviroh, P. et al. in reference [11] present a gasoline generator in their hybrid system and analyze the costs that must be paid in comparison with the different renewable energy sources. The hybrid renewable energy system is becoming popular in several South American countries such as Chile [12], Colombia [13], Brazil [14], Peru [15], etc. The big producers of solar panels are located in Europe and the United States. Today, these technologies to generate energy from renewable sources are increasingly accessible. What is also important is that these systems can complement each other, provide higher quality and a more reliable energy supply independent of the grid, and electrify rural areas. Rural areas that become more productive, in our experience, attract a greater flow of tourists to the area and nearby communities also grow indirectly [11–15]. In South America, one of the countries that has made the most progress in the last decade is Ecuador, since that country changed its constitution and modified its productive matrix, as highlighted [16,17] in its published articles. Among the most important projects carried out are those of Villonaco in the Province of Loja [18] and the Solar and Wind Park in Galapagos [19,20]. Other implementations have been attracting interest with collaborative work between countries such as those carried out by [21,22]. The applications that can be carried out with the intervention of renewable energies can be varied and according to the needs of the territory within their countries and the energy and territorial policies that are considered in their laws regarding land use. In this sense, in reference to organic constructions, we began to study the degree of utility and comfort they provide, according to references [23,24] presents a design of a telecommunications system that allows monitoring these architectures as an extension of an existing system. On the other hand, in [24], a solar energy system Energies 2020, 13, 4649 4 of 27 is considered as the only source of supply. As a result of these studies, it has been considered that Energies 2020, 13, x FOR PEER REVIEW 4 of 27 organic architectures can be better analyzed considering that there are different developments in this area, but that they require greater energy guarantees for being special architectural constructions and developments in this area, but that they require greater energy guarantees for being special their comfort is one of the prevailing demands. architectural constructions and their comfort is one of the prevailing demands. With these experiences, once again it is confirmed that a hybrid system is an excellent option for With these experiences, once again it is confirmed that a hybrid system is an excellent option for this type of construction [25–30]. Although in this article we are treating the hybrid system arranged this type of construction [25–30]. Although in this article we are treating the hybrid system arranged by solar panels and wind turbines for being the most well-known, it remains open to the fact that they by solar panels and wind turbines for being the most well-known, it remains open to the fact that can be made up of the mentioned sources and others such as sources of hydraulic energy, biomass, they can be made up of the mentioned sources and others such as sources of hydraulic energy, tidal power, geothermal, etc. biomass, tidal power, geothermal, etc. Even developments can go further, that even wind turbines must be designed in such a way Even developments can go further, that even wind turbines must be designed in such a way that that it is in harmony with these organic constructions, for example, the shape of the wind turbine it is in harmony with these organic constructions, for example, the shape of the wind turbine is is designed and built with flower-like blades and its kinematic chain is related to the stem. Such designed and built with flower-like blades and its kinematic chain is related to the stem. Such equipment has not been developed considering that there is no demand, but several families would be equipment has not been developed considering that there is no demand, but several families would happy to acquire it given their preferences for this type of architecture. The same relationship can be be happy to acquire it given their preferences for this type of architecture. The same relationship can given to solar panels that can take various forms, such as those seen in the Figure3. be given to solar panels that can take various forms, such as those seen in the Figure 3.

Figure 3. Cont.

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Figure 3. Organic architectures raised with renewable energy equipment inspired in [4]. Figure 3. Organic architectures raised with renewable energy equipment inspired in [4]. 1.2. Control Approach 1.2. Control Approach Controlling remote power systems remains a challenge, taking into account the variability of the outputControlling power remote Renewable power Energy systems System remains RES a [31 challenge,]. Focus is taking given into according account to the [32 ],variability where they of arethe addressedoutput power quite Renewable well. However, Energy in System order toRES design [31]. eFofficuscient is managementgiven according of resourcesto [32], where and tothey allow are optimaladdressed operation quite well. of eachHowever, component in order and to the design general efficient system management [32,33], we of seek resources that from and the to pointallow ofoptimal view operation of the load of iseach consumed component with and effi theciency, general that system is to say, [32,33], that we the seek lighting that from systems the point occupy of LED(light-emittingview of the load is diode) consumed bulbs, with have efficiency, the appropriate that is equipmentto say, that in the each lighting designed systems environment. occupy ForLED(light-emitting this reason, we consider diode) bulbs, that the ha systemve the appropriate for cooking andequipment heating in water each is designed independent environment. and, through For naturalthis reason, gas, itwe is consider accessible that in ourthe environment.system for cook Iting is also and a heating reason towater have is a independent new energy inputand, through such as wind,natural which gas, it we is addressaccessible in thein our section environment. below, and It thusis also not a onlyreason have to have a single a new source energy as we input considered such as inwind, our previouswhich we research address [in24 ].the Still, section every below, application and thus has not particular only have requirements a single source and as therefore we considered specific controlin our targetsprevious as confirmedresearch [24]. [34]. Still, every application has particular requirements and therefore specific control targets as confirmed [34]. Our lithium battery charge control module is programmed to start charging and finish charging Our lithium battery charge control module is programmed to start charging and finish charging at a voltage of 24 V. at a voltage of 24 V. An integrated renewable energy system (IRES) has been proposed by various researchers to An integrated renewable energy system (IRES) has been proposed by various researchers to electrify remote areas and above all allows either centralized or decentralized control. All renewable electrify remote areas and above all allows either centralized or decentralized control. All renewable energy sources have their own different operating characteristics, and it is necessary to make a standard energy sources have their own different operating characteristics, and it is necessary to make a procedure for integrating renewable energy sources in an integrated system. Generally, there are three standard procedure for integrating renewable energy sources in an integrated system. Generally, possible configurations to integrate different renewable energy sources: DC-coupled configuration, there are three possible configurations to integrate different renewable energy sources: DC-coupled AC-coupled configuration, and hybrid coupled configuration [35]. In our case, it is a 24 V DC configuration, AC-coupled configuration, and hybrid coupled configuration [35]. In our case, it is a bus-type-coupled system. 24 V DC bus-type-coupled system. This configuration has a single DC bus and all two reneable energy sources are connected to This configuration has a single DC bus and all two reneable energy sources are connected to the the bus using suitable power electronics interconnect circuits. Power sources that produce DC power bus using suitable power electronics interconnect circuits. Power sources that produce DC power connect directly to the DC bus. To supply energy to the load, we use a modern inverter that converts connect directly to the DC bus. To supply energy to the load, we use a modern inverter that converts DC/AC. DC/AC. In IRES, energy flow management is necessary to promise a continuous power supply for In IRES, energy flow management is necessary to promise a continuous power supply for the the load demand. An optimal energy management strategy ensures a highly efficient and integrated load demand. An optimal energy management strategy ensures a highly efficient and integrated energy system. Therefore, there is a need to control and monitor the renewable energy-based system. energy system. Therefore, there is a need to control and monitor the renewable energy-based system. This implies that energy sources, demand and scheduling of energy sources, and storage devices are This implies that energy sources, demand and scheduling of energy sources, and storage devices are optimized to achieve optimal energy flow in the integrated system. optimized to achieve optimal energy flow in the integrated system. Generally, the IRES control structure for energy flow management falls into three categories; Generally, the IRES control structure for energy flow management falls into three categories; centralized control arrangement, distributed control arrangement, and hybrid centralized and centralized control arrangement, distributed control arrangement, and hybrid centralized and distributed control arrangement. In all three categories, each renewable energy resource has its distributed control arrangement. In all three categories, each renewable energy resource has its own own local controller (slave controller) that determines the optimal operation of the unit based on local controller (slave controller) that determines the optimal operation of the unit based on current current information. information. The measurement signals of all energy resources, as seen in Figure4, are sent to the master The measurement signals of all energy resources, as seen in Figure 4, are sent to the master controller. The master controller acts as an energy supervisor and makes decisions about control controller. The master controller acts as an energy supervisor and makes decisions about control actions based on all measured signals and a set of predetermined goals and limitations. Based on actions based on all measured signals and a set of predetermined goals and limitations. Based on resource generation availability and load demand, it will prioritize and manage the flow of energy

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between the various renewable energy resources in the integrated system that also includes the battery bank. The centralized control structure is the most suitable for the energy management of the RES that converges to global optimal values based on the available information. It is important to note that the 1.5 kW Carbon i-1500 wind turbine was available and equipped with a direct drive permanent magnet synchronous generator. A permanent magnet synchronous generator (PMSG), a diode rectifier, and a 24 V step-down converter (DC/DC) is included. In the DC regime, the wind turbine can enter the bus at a voltage of 24 V DC without problems. Otherwise, if the wind turbine provided alternating current, an AC/DC converter would be required before entering the 24 V bus. IRES have the potential to add benefits such as energy efficiency and energy conservation, as a Energiesresult2020 of ,the13, 4649combination of renewable energy sources, which is our case. The integrated 6use of 27of different renewable energy resources increases the reliability of the power supply and the quality of power. For standalone applications, these systems always embedded with storage devices in order resource generation availability and load demand, it will prioritize and manage the ﬂow of energy to manage the stochastic behavior of renewable energy sources such as solar and wind. The control between the various renewable energy resources in the integrated system that also includes the battery system regulates the production of renewable energy sources and also generates the signals for bank. The centralized control structure is the most suitable for the energy management of the RES that storage programming subsystem and load discharge. converges to global optimal values based on the available information.

Figure 4. A block diagram with the structure of a hybrid Photovoltaic -wind micro grid system.

It isFigure important 4. A block to note diagram that thewith 1.5 the kW structure Carbon of i-1500a hybrid wind Photovoltaic turbine -wind was available micro grid and system. equipped with a direct drive permanent magnet synchronous generator. A permanent magnet synchronous 2. Hybrid PV-Wind System Structure generator (PMSG), a diode rectifier, and a 24 V step-down converter (DC/DC) is included. In the DC regime,Figure the wind 4 shows turbine the proposed can enter design the bus of ata hybrid a voltage PV-wind of 24 Vrenewable DC without energy problems. system. Otherwise,The system ifis the represented wind turbine by provideda PV that alternating can be considered current, anaccording AC/DC converterto the characteristics would be required of the beforeorganic enteringconstruction, the 24 in V bus.such a way that it can be rectangular, circular, oval, star, etc. Ultimately, it will dependIRES on have the thearchitectural potential styles to add that benefits can be such carried as energy out and effi mustciency be andadequately energy coupled conservation, to the aselectric a result power of the generation combination system. of renewable We also energy repres sources,ent a wind which turbine, is our which case. Themust integrated be dimensioned use of dibasedfferent on renewable the installed energy load resources of the organic increases construc the reliabilitytion and ofthis the system power must supply be andcomplementary the quality of to power.the PV. For There standalone is also a applications, battery bank these for energy systems storage always for embedded the hours with of lack storage of energy devices production, in order towhich manage would the stochasticsupply the behavior load. It of also renewable consists energy of a charge sources controller; such as solar the andenergy wind. inputs The enter control its systemterminals regulates and connects the production with the of renewable batteries. energyAn inverter sources is andalso also available, generates which the signals transforms for storage direct programmingcurrent into alternating subsystem current. and load discharge.

2. Hybrid PV-Wind System Structure

Figure4 shows the proposed design of a hybrid PV-wind renewable energy system. The system is represented by a PV that can be considered according to the characteristics of the organic construction, in such a way that it can be rectangular, circular, oval, star, etc. Ultimately, it will depend on the architectural styles that can be carried out and must be adequately coupled to the electric power generation system. We also represent a wind turbine, which must be dimensioned based on the installed load of the organic construction and this system must be complementary to the PV. There is also a battery bank for energy storage for the hours of lack of energy production, which would supply the load. It also consists of a charge controller; the energy inputs enter its terminals and connects with the batteries. An inverter is also available, which transforms direct current into alternating current. Energies 2020, 13, 4649 7 of 27 Energies 2020, 13, x FOR PEER REVIEW 7 of 27

If the power, generated by renewable sources (wind and solar), is insufficient according to the If the power, generated by renewable sources (wind and solar), is insufficient according to current and voltage measurements for the demand power on the load side (PL), this causes a drop in the current and voltage measurements for the demand power on the load side (PL), this causes a drop DC link voltage VDC. The positive mistake (V * DC-VDC) produces a positive reference current, in buck in DC link voltage VDC. The positive mistake (V * DC-VDC) produces a positive reference current, mode to transfer power from the power bank batteries to charge (discharge) if their State of Charge in buck mode to transfer power from the power bank batteries to charge (discharge) if their State of (SOC) is greater than the minimum value; otherwise, load shedding is required that keeps the power Charge (SOC) is greater than the minimum value; otherwise, load shedding is required that keeps balance as the power supply is less than demand and the battery is at minimum (SOCmin). In case of the power balance as the power supply is less than demand and the battery is at minimum (SOCmin). power generation exceeding load power, DC link voltage VDC increases, causing a reference current In case of power generation exceeding load power, DC link voltage VDC increases, causing a reference to control the battery bank power in boost mode, in which the power flows from the main DC link to current to control the battery bank power in boost mode, in which the power flows from the main DC the battery with the extra generated power. However, if the battery’s SOC exceeds its maximum link to the battery with the extra generated power. However, if the battery’s SOC exceeds its maximum (SOCmax), the battery charging mode stops, and the PV system operates in Maximum Power Point (SOCmax), the battery charging mode stops, and the PV system operates in Maximum Power Point Tracking (MPPT) off mode to reduce the energy generated to balance energy. Tracking (MPPT) off mode to reduce the energy generated to balance energy. In our study, we consider the basic load 18 lighting points based on 25 W led bulbs, 12 outlets to In our study, we consider the basic load 18 lighting points based on 25 W led bulbs, 12 outlets to which basic electronic equipment is connected, and 2 special 150 W outdoor reflectors. which basic electronic equipment is connected, and 2 special 150 W outdoor reflectors. To analyze the proposed system, the equivalent circuit with two diode models for the To analyze the proposed system, the equivalent circuit with two diode models for the photovoltaic photovoltaic generator has been used due to its better power extraction capacity compared to the generator has been used due to its better power extraction capacity compared to the single diode single diode model. The rotor of the wind turbine is mechanically tied to a generator to produce model. The rotor of the wind turbine is mechanically tied to a generator to produce electrical energy. electrical energy. A wind turbine is a complex system, but a reasonably simple representation is A wind turbine is a complex system, but a reasonably simple representation is possible by modeling possible by modeling the aerodynamic torque or power based on the characteristics of the turbine. A the aerodynamic torque or power based on the characteristics of the turbine. A battery solution is also battery solution is also required to balance the stochastic fluctuations of photovoltaic (PV) energy and required to balance the stochastic fluctuations of photovoltaic (PV) energy and wind energy injected wind energy injected into the load. Below in this section, a brief description is presented on how these into the load. Below in this section, a brief description is presented on how these main components main components that go into the organic architecture that is used have been modeled. that go into the organic architecture that is used have been modeled.

2.1. PV Mathematical Mathematical Model Model The solarsolar cell,cell, the the building building block block of theof the solar solar array, array, is basically is basically a P-N junctiona P-N junction semiconductor semiconductor capable ofcapable producing of producing electricity electricity due to the due photovoltaic to the photovolta effect asic stated effect by as Hong stated S. etby al. Hong [25]. S. The et photovoltaical. [25]. The cellsphotovoltaic are interconnected cells are interconnected in such a series-parallel in such a series-parallel configuration configuration to form a photovoltaicto form a photovoltaic matrix as manifestedmatrix as manifested by Kanellos, by F.Ka [nellos,26]. For F. the [26]. eff Forect, the it is effect, modeled it is with modeled the ideal with single the ideal diode single as expressed diode as inexpressed the Figure in5 the. In Figure addition 5. toIn theaddition references to the [ 24 refere–26],nces the Equations[24–26], the (1)–(3) Equations referring (1)–(3) to the referring mathematical to the modelmathematical of Figure model5 appear. of Figure 5 appear.

Figure 5. Single diode PV model.

The current Ipv we can calculate by [27,28]: The current Ipv we can calculate by [27,28]: " ! # q𝑞𝑉(Vpv((t𝑡)) ++I pv𝐼(t()𝑡I)rs𝐼) 𝐼Ipv(𝑡()t)= = 𝐼Iph((𝑡t))−𝐼Irs(𝑡t) expexp −11 (1)(1) − A𝐴cKT𝐾𝑇(t()𝑡) −

Iph is the current generated under a given insolation. Irs is the saturation current, Iph is the current Iph is the current generated under a given insolation. Irs is the saturation current, Iph is the current generated under under a a given given insolation insolation on on the the surface surface of of the the panel panel located located on on the the organic organic construction. construction. Irs is the cellular reverse saturation current. VPV is the voltage level at the array terminals photovoltaic Irs is the cellular reverse saturation current. VPV is the voltage level at the array terminals photovoltaic panel. Q is the charge of an electron. Rs is the intrinsic resistance cell. Ac is the cell deviation from the panel. Q is the charge of an electron. Rs is the intrinsic resistance cell. Ac is the cell deviation from theideal ideal P-N P-N binding binding characteristic. characteristic. K is Ktheis Boltzmann the Boltzmann constant. constant. T is Ttheis cell the celltemperature. temperature. The reverse saturation current and the photocurrent depend on the solar energy, irradiation, and temperature according to the following mathematical expressions:

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EnergiesThe 2020 reverse, 13, x FOR saturation PEER REVIEW current and the photocurrent depend on the solar energy, irradiation,8 of 27 and temperature according to the following mathematical expressions:

!3 𝑞𝐸 (1/𝑇 ) −1/𝑇( 𝑡!) T𝑇(𝑡)(t) q(Eg0(1/Tr) 1/T (t)) 𝐼Irs(𝑡()t)= = 𝐼Ior exp𝑒𝑥𝑝 − (2)(2) T𝑇re f KT𝐾𝑇(t)(𝑡)

Iph(t) = (Isc + KlT(t) Tr) λ(t)/1000 (3) 𝐼(𝑡) = (𝐼 +𝐾𝑇(𝑡) −𝑇− ) ∗∗ 𝜆(𝑡)/1000 (3) (3) where Ior is the inverse saturation current at the reference temperature Tref, Eg0 is the band gap energy where Ior is the inverse saturation current at the reference temperature Tref, Eg0 is the band gap energy of the semiconductor used in the cell, ISC is the short-circuit cellular current at the reference and solar of the semiconductor used in the cell, ISC is the short-circuit cellular current at the reference and solar temperature irradiation, K is the temperature short-circuit current, and λ is the insolation in mW/cm2. temperature irradiation, K is the temperature short-circuit current, and λ is the insolation in mW/cm2. The values of these constants are given in Table1. The values of these constants are given in Table 1.

Table 1. Parameters used in the solar system. Table 1. Parameters used in the solar system. Alt Description Parameter Value Alt Description Parameter Value 1 Charge of an electron. q 1.6 10 19 C 1 Charge of an electron. q 1.6× 10− C 22 Cell Celldeviation deviation from from the the ideal ideal p-n p-n junction junction characteristic.characteristic. Ac Ac 1.6 23 1 33 Boltzmann Boltzmann constant. constant. K K 1.38051.3805 ×10 10 NmkNmk− × − Short-circuit cell current at the reference temperature and solar ◦ 1 44 Short-circuit cell current at the reference temperature and solar irradiation. KlKl 0.00170.0017 A A °CC− irradiation. 6 5 Reverse saturation current at the reference temperature Tref. Ior 2.0793 10− A 5 Reverse saturation current at the reference temperature Tref. Ior 2.0793× × 10A 6 Reference temperature. Tref 301.18 K 6 Reference temperature. Tref 301.18 K 7 Bandgap energy of the semiconductor used in the cell. Ego 1.10 V 7 Bandgap energy of the semiconductor used in the cell. Ego 1.10 V

SolarSolar cellscells are generally modeled as as single single diode diode in in Figure Figure 55 andand double double diode diode circuit circuit model model in inFigure Figure 6.6 .Single Single diode modelmodel uses uses an an additional additional shunt shunt resistance resistance in parallel in parallel to ideal to shunt ideal diodeshunt model. diode I-Vmodel. characteristics I-V characteristics of PV cell of canPV cell be derived can be derived using single using diode single model. diode model. From here, From Equations here, Equations (4)–(8) follow(4)–(8) fromfollow the from references the references [27–30]. [27–30].

Figure 6. Double diode PV model. Figure 6. Double diode PV model. The PV cell output current is expressed mathematically as: The PV cell output current is expressed mathematically as: VN + INRSE IN = IPhoton IDiode1 IDiode2 ( ) (4) 𝐼 =𝐼− −𝐼− −𝐼− −(RParallel ) (4) PhotonPhoton currentcurrent isis expressedexpressed mathematicallymathematically as: as: G𝐺 IPhoton𝐼==[ [IPhoton 𝐼_STC_+ K+𝐾S(T(𝑇C −𝑇TSTC)])] × (5)(5) − × G𝐺STC Diode saturation current can be expressed as:

𝐼_ +𝐾(𝑇 −𝑇) 𝐼 =𝐼 = [𝑉 (6) 𝑒𝑥𝑝 ( −1 𝑉 The thermal energy absorbed by the PV solar collector is [29];

P =ηAG (7)

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Diode saturation current can be expressed as:

IShort_STC + KS(TC TSTC) IDiode1 = IDiode2 = − (6) [Vopen +K (T T )] exp STC VL C− STC 1 VThermal − The thermal energy absorbed by the PV solar collector is [29];

Ppv = ηpvgApvgGt (7) where ηpvg is PV generation eﬃciency, Apvg is PV generator area (m2), and Gt is solar irradiation 2 in tilted module plane (W/m ). ηpvg is further deﬁned as:

η = η η [1 β(Tc T )] (8) pvg r pc − − c re f where ηpc is power conditioning efficiency which is equal to one when MPPT is used, β is temperature coefficient ((0.004–0.006) per 0 C), ηr is the reference module efficiency, Tc ref is reference cell temperature in ◦C, and Tc ref is the collector reference temperature. The determination of the area of the solar panel Apvg will depend on its shape with respect to the reference plane, whether it is rectangular, circular, oval, star type, etc. as can be seen in Figure6. In organic construction, one or more panels can be installed that contrast with its architecture and will depend on special manufacturing. The area A bounded by the region formed by f and g, with x = a and x = b can be calculated by subtracting the area under g. For this purpose, we use the line integral (9).

Z b Z b Z b A = f (x)dx g(x)dx = [ f (x) g(x)]dx (9) a − a a −

According to the photovoltaic matrix grouped into several photovoltaic modules that are connected in series-parallel, this connection is allowed to have the current and voltage value of the PV matrix and therefore we can obtain its power [36,37] according to the Equations (10) and (11):

( ( ) + ( ) ) av q Vpv t Ipv t Rs Ppv(t) = npIph(t) npIrs(t)[exp ( ) 1] (10) − nsAcKT(t) − where np represents the number of modules connected in parallel, and ns is the number of cells connected in series. On the other hand, the obtainable generation of energy from a PV matrix is finally obtained: av av P (t) = Vpv(t) I (t) (11) pv ∗ pv 2.2. Wind Turbine Model The wind turbine is a machine that allows the kinetic energy of the wind to be converted into mechanical energy by colliding with its blades, allowing the main axis of the turbine to rotate and then transforming into electrical energy by receiving sufficient speed from the generator shaft. The generation of electrical energy by the wind turbine depends mainly on how much wind speed exists in the area where the turbine is located and at the same time, in which the rotors are mechanically coupled to an electric generator. It can be modeled in a simple way using the power coefficient expressed by its acronym Cp, which is closely related to the speed of the end and the angle of inclination of the blade as we can identify it in Figure7. Energies 2020, 13, x FOR PEER REVIEW 9 of 27 where ηpvg is PV generation efficiency, Apvg is PV generator area (m2), and Gt is solar irradiation in tilted module plane (W/m2). ηpvg is further defined as:

η =ηη[1 − 𝛽(𝑇 −𝑇 )] (8) where ηpc is power conditioning efficiency which is equal to one when MPPT is used, β is temperature coefficient ((0.004–0.006) per 0 C), ηr is the reference module efficiency, Tc ref is reference cell temperature in °C, and Tc ref is the collector reference temperature.

The determination of the area of the solar panel A will depend on its shape with respect to the reference plane, whether it is rectangular, circular, oval, star type, etc. as can be seen in Figure 6. In organic construction, one or more panels can be installed that contrast with its architecture and will depend on special manufacturing. The area A bounded by the region formed by f and g, with x = a and x = b can be calculated by subtracting the area under g. For this purpose, we use the line integral (9). 𝐴 = 𝑓(𝑥)𝑑𝑥 − 𝑔(𝑥)𝑑𝑥 = [𝑓(𝑥) −𝑔(𝑥)]𝑑𝑥 (9) According to the photovoltaic matrix grouped into several photovoltaic modules that are connected in series-parallel, this connection is allowed to have the current and voltage value of the PV matrix and therefore we can obtain its power [36,37] according to the Equations (10) and (11):

𝑞(𝑉 (𝑡) +𝐼 (𝑡)𝑅𝑠) 𝑎𝑣 𝑝𝑣 𝑝𝑣 𝑃𝑝𝑣(𝑡) = 𝑛𝑝𝐼𝑝ℎ(𝑡) −𝑛𝑝𝐼𝑟𝑠(𝑡)[exp( )−1] (10) 𝑛𝑠𝐴𝑐𝐾𝑇(𝑡) where np represents the number of modules connected in parallel, and ns is the number of cells connected in series. On the other hand, the obtainable generation of energy from a PV matrix is finally obtained: 𝑃 (𝑡) = 𝑉(𝑡) ∗𝐼 (𝑡) (11)

2.2. Wind Turbine Model The wind turbine is a machine that allows the kinetic energy of the wind to be converted into mechanical energy by colliding with its blades, allowing the main axis of the turbine to rotate and then transforming into electrical energy by receiving sufficient speed from the generator shaft. The generation of electrical energy by the wind turbine depends mainly on how much wind speed exists in the area where the turbine is located and at the same time, in which the rotors are mechanically coupled to an electric generator. It can be modeled in a simple way using the power coefficient expressed by its acronym Cp, which is closely related to the speed of the end and the angle of Energies 2020, 13, 4649 10 of 27 inclination of the blade as we can identify it in Figure 7.

Figure 7. Cp vs. tip speed (λ). Curve is plotted for different β. Figure 7. Cp vs. tip speed (λ). Curve is plotted for different β. Energies 2020, 13, x FOR PEER REVIEW 10 of 27 Figure7 involves analyzing the e fficiency of the turbine and allows expressing the mathematical Figure 7 involves analyzing the efficiency of the turbine and allows expressing the mathematical radiusrelationship of the (12)wind that turbine will and also ω bem a is function the angle of of the turbine relationship shaft speed.λ defined The ratio as λ C=p.,rω dependingm/v, where on r λ is relationship (12) that will also be a function of the relationship λ defined as λ = rωm/v, where r is the andthe radiusthe angle of theof inclination wind turbine of andthe bladeωm is βthe [29,30], angle can of turbinebe expressed shaft speed. (12) and The (13) ratio as:C p., depending on

λ and the angle of inclination of the blade β [29,30], can be expressed (12) and (13) as: 1 𝑟𝐶 . 𝐶(𝜆, 𝛽) = ( − 0.022 𝛽 − 2)𝑒 (12) 2 𝜆 rCr 1 rCr 0.255 β Cp(λ, β) = ( 0.022 β 2)e− (12) Generated mechanical power output 2fromλ the− wind turbine− can be written using (13) which is depending on wind velocity (VWT) = v, R is the turbine radius, 𝜌air density, and Cp is performance coefficient.Generated mechanical power output from the wind turbine can be written using (13) which is depending on wind velocity (VWT) = v, R is the turbine radius, ρa air density, and Cp is 1 performance coeﬃcient. 𝑃(𝑡) = 𝐶(𝜆, 𝛽)𝜌𝐴𝑣 (13) 21 P (t) = C (λ, β)ρ Av3 (13) For a better understanding of this aspect,WT Figure2 p 8 is representeda to its aspects that transcend for the input-outputFor a better understandingtransformation, of relati thisng aspect, wind Figure power8 andis represented electrical power. to its aspects that transcend for the input-output transformation, relating wind power and electrical power.

Figure 8. Generic scheme of energy conversion. Figure 8. Generic scheme of energy conversion. This power is possible to obtain for a certain range of wind speed. ThisThe operatingpower is possible range of to the obtain wind for turbine a certain can range be considered of wind inspeed. two regions. The operating range of the wind turbine can be considered in two regions. (a) Above a nominal wind speed v (full load). (a) Above a nominal wind speed v (full load). (b) Wind speed lower than nominal (partial load). (b) Wind speed lower than nominal (partial load). When the load is below the rated power Pr , the turbine runs at variable rotor speed, setting When the load is below the rated power 𝑃, wthe turbine runs at variable rotor speed, setting the anglethe angle of inclination of inclination of the of theblade. blade. For For wind wind speeds speeds above above the the rate rate value, value, the the turbine turbine operates operates at at a a constantconstant output output power, power, varying the blade pitch angle. OnOn the the other other hand, hand, the the operation operation of ofthe the wind wind turbine turbine is stopped is stopped for forwind wind speeds speeds less lessthan than the the nominal speed v < v [m/s] and an upper limit v > vc [m/s]. nominal speed 𝑣< 𝑣 [m/s]i and an upper limit v > 𝑣 [m/s]. The output power of the wind turbine is a function of the wind speed and is considered according to the limits expressed by (14), according to reference [7]: 0 𝑖𝑓 𝑣 <𝑣 ⎧ ⎪ 1 𝐶(𝜆, 𝛽)𝜌𝐴𝑣 (𝑡) 𝑖𝑓 𝑣 ≤ 𝑣 ≤ 𝑣 𝑃 (𝑡) = 2 (14) ⎨ ⎪ 𝑃 𝑖𝑓 𝑣 <𝑣< 𝑣 ⎩ 0 𝑖𝑓 𝑣 >𝑣 The blade angle control is linked to the mechanical aspect when speeds are too high, it is designed to regulate the speed of the generator and mitigate the loads of the components under a turbulent wind field. The pitch of the mechanical subassembly related to the blades is also mitigated somewhat.

Energies 2020, 13, 4649 11 of 27

The output power of the wind turbine is a function of the wind speed and is considered according to the limits expressed by (14), according to reference [7]:   0 i f v < v  i  1 3  Cp(λ, β)ρaAv (t) i f v v vr Pav(t) =  2 i ≤ ≤ (14) w  r  Pw i f vr < v < vc   0 i f v > vc

The blade angle control is linked to the mechanical aspect when speeds are too high, it is designed to regulate the speed of the generator and mitigate the loads of the components under a turbulent Energieswind ﬁeld.2020, 13 The, x FOR pitch PEER of REVIEW the mechanical subassembly related to the blades is also mitigated somewhat.11 of 27

2.3.2.3. Battery Battery Storage Storage Model Model TheThe battery battery is is an an important important piece piece of of equipment equipment wi withinthin a a hybrid hybrid system, system, its its number number will will depend depend onon how how much much energy energy is is available available in in hours hours when when the the load load is is not not active, active, it it provides provides us us with with the the solution solution underunder the the fluctuating ﬂuctuating action action of of renewable renewable PV-wind PV-wind energy energy sources. sources. The The equivalent equivalent battery battery model model is representedis represented by byan anelectrical electrical circuit, circuit, which which prov providesides a abetter better analysis analysis of of the the generation-power generation-power consumptionconsumption dynamics dynamics for for a a state- state-of-chargeof-charge mode mode of of operation. operation. ItIt comprises comprises an an idealized idealized voltage voltage source source with with an an in internalternal series series resistance resistance as as shown shown in in Figure Figure 9.9. EquationsEquations (15)–(18) (15)–(18) are are provided provided by by references references [28–30]. [28–30].

Figure 9. Equivalent battery circuit. Figure 9. Equivalent battery circuit. When the total output of the WT and the PV units are greater than the load [31–36], the capacity When the total output of the WT and the PV units are greater than the load [31–36], the capacity of the available battery bank at time t can be obtained by: of the available battery bank at time t can be obtained by: " # E (y) ( ) = ( ) ( ) + ( ) 𝐸l(𝑦) 𝑆𝑂𝐶SOC (𝑡)t=𝑆𝑂𝐶SOC( 𝑡t −) 1 ∗ (1−𝜎1 σ) +𝐸Eg(𝑡t) − 𝑛nbc (15)(15) − ∗ − − 𝑛ninv wherewhere SOCSOC (t()t )and and SOC SOC (t ( t− 1)1) are are the the battery battery bank bank charge charge levels levels at times at times t andt and t − 1t in 1kWh, in kWh, σ is theσ is − − self-dischargethe self-discharge rate rateper hour. per hour. SinceSince the maximum energyenergy stored stored in in the the battery batte bankry bank cannot cannot exceed exceed the maximum the maximum state ofstate charge of charge(SOCmax (𝑆𝑂𝐶), there ) is, there the following is the following restriction. restriction.

𝑆𝑂𝐶 (𝑡) ≤𝑆𝑂𝐶 (16) SOC (t) SOCmax (16) The discharge capacity of the battery bank at ≤time t can be obtained by: The discharge capacity of the battery bank at time t can be obtained by: 𝐸(𝑡) −𝐸(𝑡) 𝑛 (17) 𝑆𝑂𝐶 (𝑡) =𝑆𝑂𝐶(𝑡−1) ∗ (1−𝜎) + El(t) 𝑛 Eg(t) ninv − SOC (t) = SOC(t 1) (1 σ) + (17) where ηbf is the charging efficiency of the battery− ∗ bank.− ηbf is the ndischargeb f efficiency of the battery bank during the discharge process. where η is the charging eﬃciency of the battery bank. η is the discharge eﬃciency of the battery The bfefficiency was set equal to 1 and during charging,bf the efficiency is 0.65–0.85 depending on bank during the discharge process. the charging current, and ηinv is the efficiency of the inverter [37–41]. To supply the charge, SOC must satisfy the minimum state of charge (𝑆𝑂𝐶), so the following restriction applies during discharge:

𝑆𝑂𝐶 (𝑡) ≥𝑆𝑂𝐶 The loss of power in the supply LPS is obtained:

𝐸(𝑡) 𝐿𝑃𝑆( 𝑡) = −𝐸(𝑡) −[𝑆𝑂𝐶(𝑡−1) ∗ (1−𝜎) −𝑆𝑂𝐶]/𝑛 (18) 𝑛 Bhattacharjee AK et al. in reference [42] consider analyzing the restrictions in the power ramp; however, in this research, we welcome the literature of Anoune K. et al. according to reference [41] analyzing the loading and unloading points of the battery bank.

2.4. Inverter Performance Model

The characteristics of the inverter are given by the ratio of the input power to the inverter 𝑃 and inverter output power 𝑃. The inverter will incur conversion losses and to account for the

Energies 2020, 13, 4649 12 of 27

The efficiency was set equal to 1 and during charging, the efficiency is 0.65–0.85 depending on the charging current, and ηinv is the efficiency of the inverter [37–41]. To supply the charge, SOC must satisfy the minimum state of charge (SOCmin), so the following restriction applies during discharge:

SOC (t) SOC (18) ≥ min The loss of power in the supply LPS is obtained:

El(t) LPS (t) = Eg(t) [SOC(t 1) (1 σ) SOCmin]/nb f (19) ninv − − − ∗ − −

Bhattacharjee AK et al. in reference [42] consider analyzing the restrictions in the power ramp; however, in this research, we welcome the literature of Anoune K. et al. according to reference [41] analyzing the loading and unloading points of the battery bank.

2.4. Inverter Performance Model

The characteristics of the inverter are given by the ratio of the input power to the inverter Pinv ip − and inverter output power Pinv op. The inverter will incur conversion losses and to account for − the inverter eﬃciency losses, ηinv are used by the references [24,30] and below, Equations (20) and (21) are expressed; Pinv ip.ηinv = Pinv op (20) − − Load may not be served with the desired amount of energy. This situation is described as loss of load probability (LLP) and can be calculated using the following equation and also, LLP can represent the system reliability [30,43]; Energy_Demand LLP = (21) Energy_Served

3. Modeling and Simulation In Figure 10, the flow diagram of the hybrid PV-wind turbine system is presented, where the informative referring data is entered that will ultimately allow the energy conversion and a simulation of the energy conversion equations described in the literature of this section. The battery bank is also considered in this process, so the discharge limits are analyzed [44]. Equations (1)–(20) have been solved according to the flow diagram shown in Figure 10, where the independent input parameters are defined and other dependent parameters are calculated and integrated into the system of equations. Iterations were performed until a solution was reached with an acceptable iteration error. The tests determined that the model is significant at the 95% confidence level. A small amount is always necessary for auxiliary consumptions, such as emergency lighting and fire alarms. We consider supplying from the battery bank. The research by Diaf et al. [45] focuses on estimating the appropriate dimensions of an autonomous PV-wind hybrid system (PWHS) based on the meteorological conditions of the place, giving us some guidelines so that energy autonomy is guaranteed from a typical remote consumer with the lowest levelized energy cost (LCE), giving a high reliability of hybrid systems. Yang et al. [46] recommended an optimal design model to design hybrid solar-wind systems employing battery banks to calculate the system with optimal configurations and ensuring that the cost of the systems is minimized. Although real-time data analysis over a good number of months create greater confidence for the sizing of hybrid systems, H. X. Yang, Lu, and Burnett et al. [46] rely heavily on analyzing local weather data patterns where solar energy and wind power can compensate well for each other and can provide a good utilization factor for renewable energy applications. For the loss of power supply probability analysis (LPSP), the calculation objective functions and restrictions are established for the design of hybrid systems and to assess its reliability. Energies 2020, 13, 4649 13 of 27 Energies 2020, 13, x FOR PEER REVIEW 13 of 27

FigureFigure 10. 10.Flow Flow diagram diagram of of the the process process for for supplying supplying energy energy to to organic organic construction. construction.

TheThe hourly data considered data used in for the modelthe simulation are the solar were radiation those inof horizontalFigures 11 surface, and 12. ambient However, temperature, we must windrecognize speed, the and averaged load energy data consumption. will serve as The a outputreference power under of the normal photovoltaic conditions system without is determined extreme accordingdisturbances. to the In systemfact, several model, author alsos using consider the specificationsaveraged data of such the as photovoltaic Sami S. [48]. module However, as the it should solar radiationbe recognized data. that The real-time performance data may calculations be more ofuseful the windfor studying turbine the take system. into account the effects of the installation height which is at 10 m. The battery bank, with total nominal capacity Cbat(Ah), downloading3.1. PV Simulation is allowed up to a limit defined by the maximum discharge depth, which is specified by the system designer at the beginning of the optimal sizing process (j = 1). Then, the system configuration The photovoltaic solar system used for this purpose is carried out at the simulation level, it is will be optimized according to a dynamic search for the optimal system configuration [47]. analyzed with a matrix of ten panels with an output of 240 watts estimated at an irradiance of 1000 For each system configuration, the system LPSP will be examined to see if the load requirement W/m2 with an direct current intensity Idc of 15.14 A and an open circuit voltage Voc of 21.7 V. Module (LPSP target) can be satisfied. Then, the configurations satisfied with the lower cost load requirement, efficiency and cell temperature are 13.3% and 27 °C. Each panel is 156 × 156 mm polycrystalline type. will be subject to the simultaneous operation of the two systems (PV-wind) to produce the next Each solar panel has 36 cells and the module size is 1.482 ∗ 0.67 ∗ .035 m. The inverter output is at a generation, up to a preset number of generations, when a criterion that determines convergence constant 24 volts, so the batteries are constantly charged with 24 volts. With the help of the inverter, is satisfied. So, for the desired LPSP value, the optimal setting can be identified both technically the output AC voltage is 120 volts. Figure 10 presents typical solar insulation at the site during a and economically. calendar year at different times of the day (July 2018–June 2019). It is quite evident that the peak of solar irradiation occurs at noon. However, the average solar irradiance was used in the simulation of the photovoltaic panels. We consider the ranges of highest solar radiation and average ambient

Energies 20202020,,, 1313,,, 4649xx FORFOR PEERPEER REVIEWREVIEW 14 of 27 temperature that is around noon as shown in Figures 11 and 12. The predicted results of the The power input to the storage system is controlled by the equation C(t) = P(t) L(t) in which photovoltaic simulation at different irradiations are shown in Figures 13 and 14. The− set output P(t) = Pw (t) + Ppv(t). It is evident that the power generated by the hybrid system and the amount of voltage solar in parallel and the amount of energy generated by the photovoltaich solar i array are variable,energy stored and depend are time-dependent. mainly on insolation For the chargingand temperatures. process of It the is important battery. P tow (considert) + Ppv( tthe) > voltageLb(t). - currentThe relationship, data considered as well for as the the simulationnon-linear power were those-voltage of Figuresrelationship 11 and as shown12. However, in Figures we 11 must and 12.recognize It is quite the averaged clear that data increased will serve irradiation as a reference will result under in higher normal energy conditions conversion without efficiency. extreme Therefore,disturbances. solar In panels fact, several will be authors more efficient consider to averaged operate data in sites such with as Sami higher S. [irradiation,48]. However, such it shouldas this Ecuadorianbe recognized case that applied real-time to organic data may constructions. be more useful for studying the system.

Figure 11. Ambient t temperatureemperature profile proﬁle (July 2018–June2018–June 2019).

Figure 12. Solar i irradiancesrradiances profile proﬁle (July 2018 2018–June–June 2019).

3.1. PV Simulation The photovoltaic solar system used for this purpose is carried out at the simulation level, it is analyzed with a matrix of ten panels with an output of 240 watts estimated at an irradiance of 1000 W/m2 with an direct current intensity Idc of 15.14 A and an open circuit voltage Voc of 21.7 V. Module eﬃciency and cell temperature are 13.3% and 27 C. Each panel is 156 156 mm polycrystalline type. Each solar ◦ × panel has 36 cells and the module size is 1.482 0.67 0.035 m. The inverter output is at a constant ∗ ∗

Energies 2020, 13, 4649 15 of 27

24 volts, so the batteries are constantly charged with 24 volts. With the help of the inverter, the output AC voltage is 120 volts. Figure 10 presents typical solar insulation at the site during a calendar year at different times of the day (July 2018–June 2019). It is quite evident that the peak of solar irradiation occurs at noon. However, the average solar irradiance was used in the simulation of the photovoltaic panels. We consider the ranges of highest solar radiation and average ambient temperature that is around noon as shown in Figures 11 and 12. The predicted results of the photovoltaic simulation at different irradiations are shown in Figures 13 and 14. The set output voltage solar in parallel and the amount of energy generated by the photovoltaic solar array are variable, and depend mainly on insolation and temperatures. It is important to consider the voltage-current relationship, as well as the non-linear power-voltage relationship as shown in Figures 11 and 12. It is quite clear that increased irradiation will result in higher energy conversion efficiency. Therefore, solar panels will be more efficient to operate in sites with higher irradiation, such as this Ecuadorian case applied to Energies 2020, 13, x FOR PEER REVIEW 15 of 27 organicEnergies 20 constructions.20, 13, x FOR PEER REVIEW 15 of 27

Figure 13. Voltage photovoltaic Vpv-Current photovoltaic Ipv curves at different values of irradiance- 2 2 FigureW/m . 13.13. VoltageVoltage photovoltaic photovoltaic V pvV-Currentpv-Current photovoltaic photovoltaic Ipv curvesIpv curves at different at different values values of irradiance-W of irradiance/m -. W/m2.

22 FigureFigure 14.14.Voltage Voltage V VpvpvppPower P pv curvescurves at at different different values values of of irradiance irradiance-W-W/m/m .. Figure 14. Voltage VpvpPower Ppv curves at different values of irradiance-W/m2. 3.2. Wind Turbine Simulation 3.2. Wind Turbine Simulation The wind turbine turbine considered considered for for this this study study has has the the capacity capacity to to generate generate energy energy up up to toa speed a speed of ofup uptoThe 20 to m/s20wind m to/ s turbinereach to reach the considered themaximum maximum for allowed this allowed study power, has power, sincethe capacity since exceeding exceeding to generate this speed this energy speed it is possible up it isto possible a speedto reach toof reachtheup to runaway 20 the m/s runaway to speed reach speed ofthe the maximum of generator the generator allowed and end and power, up end beingsince up being exceeding destroye destroyedd this their speed their internal internalit is possible windings windings to orreach the or themechanical mechanical runaway parts speed parts subjected subjectedof the to generator a to rotary a rotary movement. and movement. end up If beingthe If thewind destroye wind speed speedd is their less is less than internal than 2.5 2.5 m/s, windings m /nos, noenergy energy or the is isproduced.mechanical produced. Toparts To analyze analyzesubjected in in which to which a rotary speed speed movement. range range the the If turbine turbinethe wind is is exposedspeed exposed is less to to operate, operate,than 2.5 the them/s, speed no energy profileprofile is obtainedproduced. by To a meteorologicmeteorological analyze in whichal station speed installed range on the the turbine site is available, is exposed the to same operate, meteorological the speed station profile fromobtained which by thea meteorologic solar irradiational station profileprofile installed waswas obtainedobtained on the site inin thetheis available, casecase ofof thethe the solarsolar same system.system. meteorological The wind station speed profileprofilefrom which ofof thethe the placeplace solar wherewhere irradiation thethe organicorganic profile constructionconstruction was obtained isis located locatedin the case isis presentedpresented of the solar inin Figuresystem.Figure 15 1 The5.. wind speed profileThe of diameter the place of where the turbine the organic rotor constructionis 3.0 m three is blades; located it is is presented a type of generator in Figure that15. has given us very Thegood diameter results in of cases the turbine previously rotor experienced is 3.0 m three in blades;our geographical it is a type area. of generator The nominal that haspower given is 1.5 us kW.very Thegood nominal results in speed cases atpreviously which the experienced wind turbine in our operates geographical is 9 m/s. area. The The voltage nominal is power 24 dc. is The 1.5 predictedkW. The nominalresults of speed the wind at which turbine the model wind are turbine presented operates in Figure is 9 m/s.16, where The voltagevarious iswind 24 dc.speeds The arepredicted considered results and of variousthe wind power turbine values model are are obtained, presented that in is,Figure its power 16, where production various increases wind speeds as a functare consideredion of the androtor various speed andpower when values it reaches are obtained, the speed that of is, 9 mits/s power is reached production its maximum increases power as a outputfunction whatever of the rotor its speed.speed Theand powerwhen it that reaches governs the thespeed wind of 9turbine m/s is isreached given byits maximumEquations (12power) to (output14). The whatever maximum its theoreticalspeed. The power power has that a Betzgoverns coefficient the wind of 0.59turbine which is givenis often by expressed Equations in (12 terms) to of(14). the The speed maximum of the rotor theoretical tip to the power wind has speed a Betz ratio. coefficient of 0.59 which is often expressed in terms of the speed of the rotor tip to the wind speed ratio.

Energies 2020, 13, 4649 16 of 27 Energies 2020, 13, x FOR PEER REVIEW 16 of 27

Energies 2020, 13, x FOR PEER REVIEW 16 of 27

Figure 15. Wind s speedpeed profile proﬁle (July 2018–June2018–June 2019).

The diameter of the turbine rotor is 3.0 m three blades; it is a type of generator that has given us very good results in cases previously experienced in our geographical area. The nominal power is 1.5 kW. The nominal speed at which the wind turbine operates is 9 m/s. The voltage is 24 dc. The predicted results of the wind turbine model are presented in Figure 16, where various wind speeds are considered and various power values are obtained, that is, its power production increases as a function of the rotor speed and when it reaches the speed of 9 m/s is reached its maximum power output whatever its speed. The power that governs the wind turbine is given by Equations (12) to (14). The maximum theoretical power has a Betz coeﬃcient of 0.59 which is often expressed in terms of the speed of the rotor tip toFigure the wind 15. Wind speed speed ratio. profile (July 2018–June 2019).

Figure 16. Wind speed vs. power at different values of Betz coefficient.

4. Description of the Case Study and Discussion To carry out this analysis, we went to Ecuador, a small country and very privileged to have the four geographical areas, coast, mountains, amazon and the Galapagos Islands, which are not too far from each other. Figure 17 shows the position of the Equator on the globe. Ecuador is one of the countries that crosses the equator; it was chosen by international scientists as the base to carry out geodetic research back in the 17th century, there they defined this line with the name of “equator” and it was one of the main reasons why the country has its name.

About 13 km from Quito is the place where these meetings were held, and it is called “Half of the World.” Figure 16. Wind speed vs. p powerower at different diﬀerent values of Betz coecoefficient.ﬃcient.

4.4. Description o off the Case Study and Discussion To carry out this this analysis, analysis, we we went went to to Ecuador, Ecuador, a small a small country country and and very very privileged privileged to have to have the thefour four geographi geographicalcal areas, areas, coast, coast, mountains, mountains, amazon amazon and and the theGalapagos Galapagos Islands, Islands, which which are arenot nottoo toofar farfrom from each each other. other. Figure Figure 17 shows17 shows the theposition position of t ofhe theEquator Equator on onthe theglobe. globe. Ecuador is one of the countries that crosses the equator; it was chosen by international scientists as the base to carry out geodetic research back in the 17th century, there they defined this line with the name of “equator” and it was one of the main reasons why the country has its name. About 13 km from Quito is the place where these meetings were held, and it is called “Half of the World.”

Energies 2020, 13, 4649 17 of 27 Energies 2020, 13, x FOR PEER REVIEW 17 of 27

FigureFigure 17. 17.Referential Referential diagram diagram after after energy energy conversion conversion by by hybrid hybrid systems systems in in organic organic construction. construction.

EcuadorThe most is important one of the countriesthing for our that case crosses study the is equator; that Ecuador, it was chosenhas a latitude by international of 00°00′00 scientists″, which asimplies the base some to carrybenefits out and geodetic privileges research that backcannot in eas theily 17th occur century, in other there countries they deﬁned of the world, this line such with as theradiation. name of The “equator” sun is andperpendicular it was one ofand the therefore main reasons its radiation why the countrylevels are has considered its name. one of the highest.About Of 13course, km from in many Quito aspects is the placeit can wherebe harmfu thesel, such meetings as the were need held, to use and sunscreen it is called for “Half the skin, of thebut World.” also opportunities for energy generation, as is our purpose in this article. TheNature most is important so wise in thing which for everything our case study is balanc is thated and Ecuador, in the has city a of latitude Quito ofyou 00 can◦000 see00”, unusual which impliessituations some in beneﬁtsits art centers: and privileges Clear examples that cannot are how easily an occuregg can in otherbe balanced countries on the of the tip world,of a nail, such water as when passing through a funnel does not rotate but falls, and at various points you tend to walk in a

Energies 2020, 13, 4649 18 of 27 radiation. The sun is perpendicular and therefore its radiation levels are considered one of the highest. Of course, in many aspects it can be harmful, such as the need to use sunscreen for the skin, but also opportunities for energy generation, as is our purpose in this article. EnergiesNature 2020, 13 is, x so FOR wise PEER in REVIEW which everything is balanced and in the city of Quito you can see unusual18 of 27 situations in its art centers: Clear examples are how an egg can be balanced on the tip of a nail, water whenstraight passing line. Information through a funnelon many does of notthese rotate featur butes falls,can be and found at various in the pointsvarious you pavilions tend to of walk this inmuseum a straight city. line. Information on many of these features can be found in the various pavilions of this museumAs indicated, city. it makes some points of Ecuador the closest to the sun on the planet, and the furthestAs indicated,from the core it makes of the some earth. points This ofalso Ecuador causes theconditions closest to that the produce sun on the quite planet, interesting and the endemic furthest fromfauna the and core flora. of theIn our earth. case, This where also causeswe seek conditions to tackle organic that produce constructi quiteons, interesting it can be endemic really interesting fauna and ﬂora.research. In our case, where we seek to tackle organic constructions, it can be really interesting research.

4.1. Construccion Site To carrycarry outout thisthis project,project, itit waswas importantimportant to decidedecide on a place where they have enough area to carry out organic construction, joinjoin thethe decisiondecision toto carrycarry outout aa site of this type and that the place meets some minimum conditions so that its environmentenvironment is notnot altered.altered. A great opportunityopportunity and decisiondecision was found to to carry carry out out the the location location in in the the town town of ofEl ElValle Valle corresponding corresponding to the to theCanton Canton Cuenca, Cuenca, See SeeFigure Figure 18. It 18 has. It a has land a landarea of area 2 hectares, of 2 hectares, here a here site for a site an forairplane-type an airplane-type hotel was hotel decided was decided as shown as shownin Figure in 17, Figure and 17 can, and even can be even viewed be viewed using Google using Google Earth. Earth.

Figure 18. Preliminary outline of the organi organicc construction type airplane.

The topographytopography of of the the place place allows allows internally internally to build to build the environments the environments as comfortable as comfortable as possible, as withpossible, natural with light natural ducts duringlight ducts the day during and thethe necessaryday and lightingthe necessary at night lighting using the at renewable night using energy the system.renewable With energy the supportsystem. ofWith the the walls, support focused of the light wa bounceslls, focused are light caused bounces in certain are caused places asin showncertain inplaces Figure as shown19. It isin important Figure 19. toIt indicateis important that to guests indicate of this that organic guests of construction this organic can construction easily change can environmentseasily change environments with a pleasant with panoramic a pleasant view, panoramic fresh air, view, and services. fresh air, and services. The importanceimportance ofof thesethese organicorganic constructions constructions inspired inspired by by [25 [25]] not not only only uses uses the the interior interior space space of theof the plane’s plane’s frame, frame, but but also also allows allows the the construction construction of aof subway, a subway, including including its access its access through through the tail,the astail, shown as shown in the inprototype the prototype of Figure of Fi gure20 and 20 alsoand foralso the for laterals. the laterals. Figure 21 presents the comparative results between the prediction model and the experimental curve of the wind turbine.

Energies 2020, 13, 4649 19 of 27 Energies 2020, 13, x FOR PEER REVIEW 19 of 27 Energies 2020, 13, x FOR PEER REVIEW 19 of 27

FigureFigure 19. General19. General scheme scheme of of organic organic airplane-typeairplane-type construction construction supp suppliedlied by bya hybrid a hybrid renewable renewable Figure 19. General scheme of organic airplane-type construction supplied by a hybrid renewable energyenergy system. system. energy system.

(a) (b) (a) (b) Figure 20. (a) Model where you can see the accesses and rest places at the bottom of the tail. (b) Frame Figureof the 20. tail(a) of Model the plane where before you carrying can see ou thet the accesses high decoration and rest places of environments. at the bottom of the tail. (b) Frame Figure 20. (a) Model where you can see the accesses and rest places at the bottom of the tail. (b) Frame of the tail of the plane before carrying out the high decoration of environments. of the tail of the plane before carrying out the high decoration of environments. EnergiesFigure 2020, 1213, xpresents FOR PEER the REVIEW comparative results between the prediction model and the experimental20 of 27 curve of the wind turbine. Figure 21 presents the comparative results between the prediction model and the experimental In order to validate the prediction of our model and given that the data of temperature, irradiance, curve of the wind turbine. and wind speeds at the site where the location of the organic airplane-type construction is being carried outIn must order be to evaluated validate andthe predictioncompared withof our the model experime andntal given curves, that thewe havedata ofchosen temperature, to use the irradiance, data of andsolar wind radiation speeds andat the average site where wind the speeds location that ofwould the organic turn out airplane-type to be the most construction characteristic is beingof the carriedsite. outFigure must 22a,bbe evaluated shows the and prediction compared of thewith model the experime referring ntalto the curves, solar PVwe andhave wind chosen turbine to use in termsthe data of of solarvoltage-amperage radiation and averageand Power-speed wind speeds respectively. that would It isturn quite out evident to be thefrom most the characteristicdata presented of in the the site. Figurefollowing 22a,b figures shows that the theprediction numerical of modelthe model predicted referri theng output to the datasolar very PV andwell. wind turbine in terms of voltage-amperageComparison and between Power-speed experimental respectively. data and thatIt is of quite prediction evident of thefrom math theematical data presented model of thein the followingsolar panel figures at 600 that W/m the2 numericalhas been shown model inpredicted Figure 22. the Of output course data, in thisvery project well. 10 solar panels are consideredComparison for their between high experimentalpotential for solar data irradiation and that of and prediction a single ofturbine; the math however,ematical it remains model of to the solarbe panelanalyzed at 600with W/m the2 increasehas been in shown more inwind Figure turbines 22. Of how course the, insystem this projectcan increase 10 solar in panelsenergy are consideredproduction. for Despite their high the factpotential that this for type solar of irradiationconstruction and is exclusive a single andturbine; the potential however, beneficiaries it remains to behave analyzed sufficient with economic the increase resources in moreto make wind their turbines projects ahow reality, the it system must be can considered increase that in theirenergy production.energy production Despite systemsthe fact arethat not this excessively type of cons high.truction It is important is exclusive to note and that the until potential now what beneficiaries exists haveof the sufficient construction economic progress resources on the tosite make there their is an projectsadvantage a reality,with which it must people be consideredlived in the fieldthat theiris energythat at production an underground systems level are thenot noiseexcessively produced high. by It the is importantturbine is null,to note included that until at night, now what it really exists means that this type of technology they give samples that go very well with organic constructions of the construction progress on the site there is an advantage with which people lived in the field is and that according to the designs we can achieve luxurious final environments. that at an underground level the noise produced by the turbine is null, included at night, it really means that this type of technology they give samples that go very well with organic constructions andFigure thatFigure according 21. Representative 21. Representative to the designs curves curves of we the of can mathematicalthe achievemathematical luxurious model model and finaland the the experimentalenvironments. experimental curve curve in ain wind a wind turbine. turbine.

(a) (b)

Figure 22. (a) Comparison of voltage—current experimental data and mathematical model at 600 W/m2. (b) Comparison of voltage—power experimental data and mathematical model at 600 W/m2.

maximum state of charge (푆푂퐶푚푎푥 ), and in turn is not minimized during discharge (푆푂퐶푚𝑖푛). With these restrictions that logically depend on the lifestyle of people and the type of charge, we use Equations (15) and (17) considering that there is an average chargeability of 8 h and 8 h of discharge, it implies that we need 8 batteries of 300 Ah at 24 V in parallel connection, also considering that there is a deterioration factor that would be progressing even if there are the best environmental and

Energies 2020, 13, x FOR PEER REVIEW 20 of 27

Energies 2020, 13, 4649 20 of 27

In order to validate the prediction of our model and given that the data of temperature, irradiance, and wind speeds at the site where the location of the organic airplane-type construction is being carried out must be evaluated and compared with the experimental curves, we have chosen to use the data of solar radiation and average wind speeds that would turn out to be the most characteristic of the site. Figure 22a,b shows the prediction of the model referring to the solar PV and wind turbine in terms of voltage-amperage and Power-speed respectively. It is quite evident from the data presented Figure 21. Representative curves of the mathematical model and the experimental curve in a wind in the following ﬁgures that the numerical model predicted the output data very well. turbine.

(a) (b)

FigureFigure 22. 22.( a(a)) Comparison Comparison of of voltage—currentvoltage—current experimentalexperimental d dataata and and m mathematicalathematical m modelodel at at 60 6000 2 2 WW/m/m.(2. b(b)) Comparison Comparison ofof voltage—powervoltage—power experimentalexperimental d dataata and and m mathematicalathematical m modelodel at at 60 6000 W W/m/m2. .

4.2.Comparison Battery Bank between experimental data and that of prediction of the mathematical model of the solar panel at 600 W/m2 has been shown in Figure 22. Of course, in this project 10 solar panels are consideredAfter forseveral their acquired high potential experiences for solar carried irradiation out in remote and a single places turbine;, it is important however, to itbe remains clear about to be the model used in Figure 9 and the respective literature, a fairly simple model that has given us very analyzed with the increase in more wind turbines how the system can increase in energy production. good results, especially in the application made according to reference [37]. Based on this adopted Despite the fact that this type of construction is exclusive and the potential beneficiaries have sufficient model, we must be careful when sizing the battery bank so that the SOC does not exceed the economic resources to make their projects a reality, it must be considered that their energy production maximum state of charge (푆푂퐶 ), and in turn is not minimized during discharge (푆푂퐶 ). With systems are not excessively high.푚푎푥 It is important to note that until now what exists of the construction푚𝑖푛 these restrictions that logically depend on the lifestyle of people and the type of charge, we use progress on the site there is an advantage with which people lived in the field is that at an underground Equations (15) and (17) considering that there is an average chargeability of 8 h and 8 h of discharge, level the noise produced by the turbine is null, included at night, it really means that this type of it implies that we need 8 batteries of 300 Ah at 24 V in parallel connection, also considering that there technology they give samples that go very well with organic constructions and that according to is a deterioration factor that would be progressing even if there are the best environmental and the designs we can achieve luxurious final environments.

4.2. Battery Bank After several acquired experiences carried out in remote places, it is important to be clear about the model used in Figure9 and the respective literature, a fairly simple model that has given us very good results, especially in the application made according to reference [37]. Based on this adopted model, we must be careful when sizing the battery bank so that the SOC does not exceed the maximum state of charge (SOCmax), and in turn is not minimized during discharge (SOCmin). With these restrictions that logically depend on the lifestyle of people and the type of charge, we use Equations (15) and (17) considering that there is an average chargeability of 8 h and 8 h of discharge, it implies that we need 8 batteries of 300 Ah at 24 V in parallel connection, also considering that there is a deterioration factor that would be progressing even if there are the best environmental and ventilation conditions. The system is speciﬁcally designed for the worst case that reaches its maximum utilization power of 3.9 kW. In the extreme scenario that the load is maximum (coincidence factor equal Energies 2020, 13, 4649 21 of 27 to 1), 8 h can be used and approximately 15% of charge will be maintained in the battery bank. Not so likely scenario but we must assume the most unfavorable condition.

4.3. Precision Degree of the Model We are aware that the mathematical model we build will differ from the experimental curve both in relation to the production of energy by the wind and solar sources. To determine the degree of precision,Energies 2020 we, 13, usex FOR the PEER iterative REVIEW method proposed by the reference [38], there are really21 of various 27 methodsventilation to estimate conditions. the error, The then system in Tables is specifically2 and3 we designed can obtain for the the worst percentages case that of reaches e a% as its stated in themaximum Figures 23 utilization and 24 depending power of 3.9 on kW. the In casethe extreme of each scenario energy that source. the load As weis maximum observed, (coincidence in no case does it exceedfactor 5%, equal which to 1), speaks8 h can be volumes used and for approximately the model used. 15% of It charge is very will important be maintained that thein the data battery obtained in thebank. field Not is using so likely well-calibrated scenario but we and must certified assume equipment, the most unfavorable so we can condition greatly. guarantee current and voltage measurements. The4.3. Precision measurements Degree of the that Model are carried out are always tedious and above all, they must coincide with the simulatedWe are aware irradiation, that the mathematical which in this model case iswe 600 build W/m will2, onlydiffer in from this waythe experimental will we be comparingcurve the valuesboth in and relation obtaining to the production the level of of variation energy by between the wind the and simulated solar sources. and To the determine measured. the degree Inof theprecision, case of we the use turbine the iterative it is much method more proposed practical by to the obtain reference the measurements [38], there are really with avarious tachometer givingmethods different to estimate speed values. the error, At then different in Table speeds 2 and values, 3 we thecan respectiveobtain the percentages power is obtained of ea% as momentstated by momentin the and Figure thes respective 23 and 24 curvedepending is obtained. on the case In fact, of each wind energy turbine source. construction As we observed, companies in no in case the final does it exceed 5%, which speaks volumes for the model used. It is very important that the data tests do it carefully in a similar way. obtained in the field is using well-calibrated and certified equipment, so we can greatly guarantee Thecurrent determination and voltage measurements. of errors can be obtained through different methods; in our case we use the relationThe (21) measurements widely used that in referenceare carried [38 out] to are even always use tedious much more and above accurate all, methodsthey must for coincide calculating errors.with We the can simulated determine irradiation, that the which error in in this neither case is case 600 exceedsW/m2, only 5%. in this way will we be comparing Herethe values is the and relationship obtaining the for level calculating of variation errors: between the simulated and the measured. In the case of the turbine it is much more practical to obtain the measurements with a tachometer giving different speed values. At differentValor actualspeed values,Valor the medido respective power is obtained moment by εa = − 100% (22) moment and the respective curve is obtained.Valor In actualfact, wind turbine construction companies in the final tests do it carefully in a similar way.

FigureFigure 23. 23.Referential Referential graph graph for the the estimation estimation of oferrors errors between between the mathematical the mathematical model and model the and experimental curve of the PV system. the experimental curve of the PV system.

Energies 2020, 13, x FOR PEER REVIEW 22 of 27

Table 2. Summary table of quantification of maximum percentage errors regarding the PV system.

Terms Reference Curve 1 Reference Curve 2 Ea (%) 1 29.3 28.3 3.41296928 Energies 2020, 13, 4649 22 of 27 2 28.4 27.7 2.46478873 3 27.3 26.8 1.83150183 Table 2. Summary4 table of quantiﬁcation1.6 of maximum percentage1.6 errors regarding0 the PV system. 5 2.27 2.27 0 Terms 6 Reference2 Curve 1 Reference2.28 Curve 2 E0.a21881838(%) 7 12 29.3.3 28.32.28 3.412969280.86956522 8 22 28.4.36 27.72.28 2.464788733.38983051 3 27.3 26.8 1.83150183 9 42. 1.638 1.62.3 3.36134454 0 The determination5 of errors can 2.27 be obtained through 2.27 different methods; 0 in our case we use the 6 2 2.28 0.21881838 relation (21) widely used in reference [38] to even use much more accurate methods for calculating 7 2.3 2.28 0.86956522 errors. We can determine8 that the error 2.36 in neither case exceeds 2.28 5%. 3.38983051 Here is the relationship9 for calculating 2.38 errors: 2.3 3.36134454 푉푎푙표푟 푎푐푡푢푎푙 − 푉푎푙표푟 푚푒푑𝑖푑표 휀푎 = 100% (22) It is important to indicate that the model푉푎푙표푟 referring 푎푐푡푢푎푙 to the wind turbine predicts quite well at low speeds, asIt is observed important in to Figure indicate 24 and that Tablethe model3; however, referring for to high the wind speeds, turbine the margin predicts of quite error well will at increase low considerablyspeeds, as soobserved the model in Figure cannot 24 beand used. Table The 3; however analysis, for carried high outspeeds is based, the margin on the of average error will wind characteristicsincrease considerably in Ecuador so the according model cannot to the be reference used. The [39 analysis] presented carried by out the isEcuadorian based on the Ministry average of Renewablewind characteristics Energy. In in the Ecuador wind map,according it is identiﬁedto the reference that the[39] windspresented in Ecuadorby the Ecuadorian in the inter-Andean Ministry of Renewable Energy. In the wind map, it is identified that the winds in Ecuador in the inter-Andean mountain range are at an average annual speed of 8 m/s at a height of 30 m. There are other points that mountain range are at an average annual speed of 8 m/s at a height of 30 m. There are other points exceed this speed especially in Bolivar, Azuay, and Loja where the located wind farms are located and that exceed this speed especially in Bolivar, Azuay, and Loja where the located wind farms are located others in projection, places destined for energy production on a larger scale, which is not the case to and others in projection, places destined for energy production on a larger scale, which is not the case analyzeto analyze these these sites andsites ourand studyour study does does not not have have that that purpose. purpose.

FigureFigure 24. 24.Referential Referential graphgraph for the the estimation estimation of oferrors errors between between the mathematical the mathematical model modeland the and experimental curve of the wind turbine. the experimental curve of the wind turbine.

Table 3. Summary table of quantiﬁcation of maximum percentage errors regarding of the wind turbine.

Terms Reference Curve 1 Reference Curve 2 Ea (%) 1 200 192 4 2 360 345 4.16666667 3 580 555 4.31034483 4 875 835 4.57142857 Energies 2020, 13, x FOR PEER REVIEW 23 of 27

Table 3. Summary table of quantification of maximum percentage errors regarding of the wind turbine.

Terms Reference Curve 1 Reference Curve 2 Ea (%) 1 200 192 4 2 360 345 4.16666667 3 580 555 4.31034483

Energies 2020, 13, 4649 4 875 835 4.57142857 23 of 27

4.4. Complementary Aspects 4.4. Complementary Aspects Next in Figure 25, the environments projected in the underground part of the organic airplane- type Nextconstruction in Figure 25are, thepresented. environments Reference projected [4] inin thedicates underground that these part environments of the organic should airplane-type be as constructionconformable areas possible. presented. As Reference we noticed [4] indicatesthese design thats these hold environmentsthat deep inspiration should be of as what conformable a mother’s as possible.womb is, Asmaking we noticed it a warm these and designs welcoming hold that home. deep Th inspiratione lighting system of what used a mother’s plays an womb important is, making role itin athe warm environments, and welcoming direct home. light The is avoided, lighting systemas it may used not plays make an coexistence important roleso pleasant. in the environments, It is sought directthat there light be is a avoided, diversity as of it electrical may not makecircuits coexistence that supply so the pleasant. lighting It systems is sought with that the there intention be a diversity of not ofdepending electrical 100% circuits of one that of supply them. the Natural lighting lighting systems is also with a source the intention of life, ofso notit is dependingconsiderable 100% that of there one ofare them. external Natural and lateral lighting ducts is also that a allow source its of entry. life, so Of it course, is considerable in this organic that there construction are external there and are lateral two ductsfloors, that one allow on the its surface entry. Of (own course, plane), in this and organic one underground construction where there are the two guest ﬂoors, is provided one on the with surface rest (ownand has plane), all the and basic one services. underground where the guest is provided with rest and has all the basic services.

Figure 25. Main views of the interior lighting system.

Figure 2626 showsshows the the progress progress that that organic organic constructi constructionon has, has, it is it a is project a project that that aims aims to break to break the thegeneral general paradigms paradigms of the of sectors the sectors in Cuenca in Cuenca of Ecua ofdor Ecuador based on based the general on the pl generalanning. planning. It is important It is importantto indicate tothat indicate although that the although raised construction the raised construction must be well must carried be well out, carried it should out, not it should be neglected not be neglectedthat the entire that theenvironment entire environment must be considered must be considered in the project. in the That project. is to That say, is all to the say, landscape all the landscape aspect aspectthat is thataround is around is studied is studied so that so it that is cozy. it is cozy. Plants Plants to be to planted be planted in their in their surroundings surroundings should should be bemedium medium in size. in size. High-growth High-growth plants plants can be can an be obstac an obstaclele for the for wind the windto reach to reachthe wind the windturbine turbine at the atcurrent the current speed, speed, likewise likewise if there if thereare plants are plants that are that large, are large, they theycan create can create shadows shadows on the on panels the panels and andnotEnergies have not 2020 have the, 13 expected, thex FOR expected PEER energy REVIEW energy production. production. 24 of 27

Figure 26. General views of the environment regarding organic construction.

5. Conclusions The organic architectures are awakening interest in certain countries, they are exclusive and give rise to making different designs and models that contrast with the environment depending on the area in which it will be located. Renewable energies in this type of construction begin to play an important role due to the fact that the vast majority of commercial distribution networks are distant. Generally, where these architectures are located, it is recommended that the entire environment contrast in a natural and ecological way, making it more welcoming. Depending on the energy available, it is also possible to extend the lighting circuits to the outdoors, especially to walkways or parking lots. The shapes and sizes, especially of panels and wind turbines, are recommended to be exclusive and to contrast with the respective organic architectures. It surely implies an increase in your costs but in the end, it will be worth it. Focusing on the two main sources of renewable energy discussed in this article, we have presented a summary of mathematical modeling. The non-linear characteristics of the wind energy system and the photovoltaic system, such as power, voltage, and current, are summarized in the quest to achieve greater power depending on the resource available on the site. The energy conversion equations that describe the total power generated by a hybrid solar energy system photovoltaic and wind turbine, introduced and integrated simultaneously. To validate this simulation model, the aforementioned equations were coded with MATLAB 2020 and can be used as optimization and a design tool. Comparison between model predictions and on-site data according to the airplane-type organic construction being built and adapting its green environment in the Cuenca of Ecuador, as shown in Figure 26. It was shown that the model predicted data well under various conditions. According to field tests, it is possible to supply enough cargo to all the organic construction detailed in Figures 18 and 19; these are 8 bedrooms, 3 rooms, 3 entrance halls, 1 restaurant, and 1 restroom with a view of the river. Particularly they are lighting circuits and outlets that feed these comfortable environments such as those considered in Figure 25. It is important to indicate that for cooking and heating water in this case liquefied petroleum gas, very accessible in our environment, has been considered. However, it is also possible to join the renewable energy system in an urgent situation or, in turn, expand coverage with these or other renewable energy systems that may be hot water tanks. According to the functional tests, the battery bank provides us with 8 h of backup with 100% charge, that is to say at 3.2 kW between lighting, outlets, and two special charges. It implies that the supply of energy to all environments and the continuity of services are guaranteed with complete safety, including a remainder for 0.7 kW situations for extreme situations of cloudiness and an increase in the future load as an increase in lighting in some specific sector or reduction of the quality of the batteries. These constructions in Ecuador have created novelty and above all the upper and upper middle class are building this type of average buildings, taking advantage of the benefits that solar energy offers in its simple transformation into electrical energy. In this research where organic constructions are presented, the nature of the study is different but we seek to focus its approach in a similar direction to the regularly published literature in the

Energies 2020, 13, 4649 24 of 27

5. Conclusions The organic architectures are awakening interest in certain countries, they are exclusive and give rise to making different designs and models that contrast with the environment depending on the area in which it will be located. Renewable energies in this type of construction begin to play an important role due to the fact that the vast majority of commercial distribution networks are distant. Generally, where these architectures are located, it is recommended that the entire environment contrast in a natural and ecological way, making it more welcoming. Depending on the energy available, it is also possible to extend the lighting circuits to the outdoors, especially to walkways or parking lots. The shapes and sizes, especially of panels and wind turbines, are recommended to be exclusive and to contrast with the respective organic architectures. It surely implies an increase in your costs but in the end, it will be worth it. Focusing on the two main sources of renewable energy discussed in this article, we have presented a summary of mathematical modeling. The non-linear characteristics of the wind energy system and the photovoltaic system, such as power, voltage, and current, are summarized in the quest to achieve greater power depending on the resource available on the site. The energy conversion equations that describe the total power generated by a hybrid solar energy system photovoltaic and wind turbine, introduced and integrated simultaneously. To validate this simulation model, the aforementioned equations were coded with MATLAB 2020 and can be used as optimization and a design tool. Comparison between model predictions and on-site data according to the airplane-type organic construction being built and adapting its green environment in the Cuenca of Ecuador, as shown in Figure 26. It was shown that the model predicted data well under various conditions. According to field tests, it is possible to supply enough cargo to all the organic construction detailed in Figures 18 and 19; these are 8 bedrooms, 3 rooms, 3 entrance halls, 1 restaurant, and 1 restroom with a view of the river. Particularly they are lighting circuits and outlets that feed these comfortable environments such as those considered in Figure 25. It is important to indicate that for cooking and heating water in this case liquefied petroleum gas, very accessible in our environment, has been considered. However, it is also possible to join the renewable energy system in an urgent situation or, in turn, expand coverage with these or other renewable energy systems that may be hot water tanks. According to the functional tests, the battery bank provides us with 8 h of backup with 100% charge, that is to say at 3.2 kW between lighting, outlets, and two special charges. It implies that the supply of energy to all environments and the continuity of services are guaranteed with complete safety, including a remainder for 0.7 kW situations for extreme situations of cloudiness and an increase in the future load as an increase in lighting in some specific sector or reduction of the quality of the batteries. These constructions in Ecuador have created novelty and above all the upper and upper middle class are building this type of average buildings, taking advantage of the benefits that solar energy offers in its simple transformation into electrical energy. In this research where organic constructions are presented, the nature of the study is different but we seek to focus its approach in a similar direction to the regularly published literature in the field of renewable energy. Although the topic lends itself to present a significant novelty, our interest on this occasion is that the reader finds the relationship with the established literature and in the new editions disseminate specific aspects that have greater innovation. In this way, the research is open to researchers in the area to experience new experiences and give different approaches.

Author Contributions: Data curation, D.I., C.F.-V. and S.P.G.; Formal analysis, D.I. and D.B.-D.; Writing—original draft, D.I. and S.P.G. and D.B.-D.; Writing—review and editing, D.B.-D. All authors have read and agreed to the published version of the manuscript. Funding: The University of León supported the contributions of David Borge-Diez from the Department of Electrical, Systems and Automation Engineering and Daniel Icaza, PhD student. Santiago Pulla Galindo and Energies 2020, 13, 4649 25 of 27

Carlos Flores-Vázquez members of the GIRVyP Group who received the support of the Catholic University of Cuenca in Ecuador. Acknowledgments: Both the University of León of Spain and the Catholic University of Cuenca are thanked for promoting this research, pleasantly promoting the internationalization processes. To David Borge-Diez, researcher at UNILEON, for his contribution of the highest value so that this research has had the expected success. Conﬂicts of Interest: The authors declare no conﬂict of interest.

References

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