Design of Low-Carbon and Environmentally-Friendly Intelli- Gent Air Ventilation and Cooling Device

Design of Low-carbon and Environmentally-friendly Intelli- gent Air Ventilation and Cooling Device

Zhiqiang ZHANG, Mei DONG, Yanchao LIU, Yizhen LIU Liaoning Institute of Science and Technology

Abstract: With the new trend of carbon neutral social development as the research background, this paper proposes design concept for a low-carbon and environmentally friendly intelligent air exchange and cooling device, relying on mechanical principles, technology and knowledge of com- puters and automation for the creation of an energy-saving society, and low-carbon living. In re- sponse to the user experience problems of electric fans and air conditioners, as well as the high energy consumption problem, an implementation plan is proposed to use of the existing clean resources to develop the air exchange device. Based on the design concept and implementation plan, a prototype has been prepared to achieve no pollution and zero emission. It also makes full use of solar energy resources and achieves intelligent control. The design solution is in line with the goal of a carbon neutral economy and meets the need for energy saving and emission reduction. This study can provide ideas and references for other industrial low carbon designs also. Keywords: Low carbon; Environmental protection; Air exchange unit; Computer DOI: 10.47297/taposatWSP2633-456918.20200106

Introduction: At the general debate of the 75th session of the UN General Assembly, China sol- emnly announced to the international community that it would increase its autonomous national contribution, adopt stronger policies and measures, and strive to peak of carbon dioxide emissions before 2030, and work towards carbon neutrality before 2060 [1~4]. The declaration has been unan- imously praised by international public opinion and was considered a milestone in the history of global climate governance. However，increasing carbon emissions have long been the main means of driving China’s economic development, and the proposed carbon neutrality target is an important test of China’s economic development transformation，prompting China’s economy to shift from high-speed development to high-quality development. Energy efficiency will be the most important

About the author: Zhiqiang ZHANG (1995-02), male，Han nationality, Tianshui City, Gansu Province, School Students, machine design; Mei DONG (1999-10)，male, Han, ShenYang City Liaoning Province, School Students, Computer application; Yanchao LIU (1982-02), Female, Han, chaoyang, Teacher, Master, Computer Teaching and application; Yizhen LIU (1967-12), Female, man, shandong, Teacher, undergraduate, Computer Teaching and application. Funded project: Innovation and Entrepreneurship Training Program for College Students of Liaoning Uni- versity of Science and Technology in 2020（202011430069）.

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and economical means to achieve the goal of carbon neutrality in China [5,6]. The concept of energy conservation and emission reduction should be deeply embedded in each of our daily work and design. Only through comprehensive emission reduction and low carbon living can we achieve carbon neutrality as soon as possible. And the realization of this goal is an all-round system project, not just a matter of heavy industrial development. For our daily life, energy saving, electricity saving is one of the very effective means. Electricity, as the main source of energy, is closely related to our daily life, but 80%of electricity in China comes from thermal power [7], that is, electricity is generated by burning coal, which is a highly polluting and carbon-emitting industry [8]. We cannot live without electricity in our daily life, but we can achieve energy saving and emission reduction work through reasonable design and time saving of electricity, which is all around us. This paper presents a simple, commonly applied exhaust system as an example of a low carbon and environmentally friendly design solution, proposes a practical and effective energy saving design solution, briefly describes the ways to implement the solution, and, at the same time, evaluates and analyses the application effect. In this way, a non-polluting, zero-emission solution to nature is provided for reference and learning by other scholars.

1. Problems with Conventional Air Exchange Units (1) Electric fan principles and use issues Ventilation units are the most common equipment in our lives. Currently, the main devices for ventilation and heat dissipation and air exchange are fans and air conditioners. Electric fans use electrical energy to convert into mechanical energy, by driving the electric fan blades to make the surrounding air flow and take away heat by convection. But at the same time, due to the presence of electrical resistance, some of the electrical energy is inevitably converted into heat [9]. The drawbacks of electric fans are more obvious. It can be uncomfortable if they blown on for too long. Turning it down does not work. Adjusting too much increases the noise and makes the experience worse and noise increases. Affects the quality of sleep. In addition, the blade design tends to collect dust and traditional fans also have a violent wind sensation that is uneven and uncomfortable. Electric fans usually consume more energy and the experience is less than ideal. (2) Air conditioning principles and use issues Another common air exchange and cooling device and appliance is the air conditioner [10].The air conditioner compresses the gaseous refrigerant into a high-temperature，high-pressure gaseous state through the compressor and sends it to the condenser for cooling, where it becomes medium- temperature, high-pressure liquid refrigerant that enters the drying bottle for filtering and dehumid- ification. The refrigerant is then returned to the compressor for further compression, continuing the cycle of refrigeration. When heating, there is a four-way valve to make the flow of Freon in the condenser and evaporator in the opposite direction than when cooling, so when heating, the outdoor air is blowing cold air, the indoor unit is blowing hot air. When cooling, the outdoor unit blows hot

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air and the indoor unit blows cold air. However, air conditioning has its own obvious disadvantages. The evaporator accumulates dust and breeds bacteria, which can lead to indoor air pollution. There is also a certain amount of noise, which is unacceptable to some people. The user experience is flawed by the fact that the room is drier when the air conditioner is on. In addition, the most electrical appliances, consume more electricity and have high energy consumption. In order to solve these problems of air conditioners, higher-grade air conditioners currently use inverter technology [11], but, because inverter air conditioner technology is not as technically pure as fixed-frequency air conditioners, and because the requirements for equipment are relatively high, air conditioners are more prone to the phenomenon of failure. Repairs are more frequent and are very expensive. Inverter air conditioners are generally more expensive，and the cost of air conditioning is also higher. Most of all, the technology of inverter air conditioners is not yet perfect. Although its advantages are many, we all know that the more advanced the machine is, the more complex the parts are, and the probability of problems will be increased accordingly, and the technology of the core components of the inverter is also monopolized by Japan. In short, fans and air conditioners as appliances, both require a high level of energy consumption and both also have some problematic user experiences and are common electrical products used in daily families. The cumulative energy consumption is very high. It is one of the major sources of carbon emissions for every household.

2. Low Carbon and Environmentally Friendly Intelligent Design Solutions (1) Design philosophy’ The design product mainly realizes ventilation and heat exchange. On the one hand, it can provide fresh and clean air to the room, reduce the concentration of CO2 and various harmful substances in the room, ensure the freshness of indoor air, so that people have a healthy and comfortable living and working environment; on the other hand，using the temperature difference between the exhausted dirty air and the air introduced into the room, so that the two gases can exchange heat while conducting air exchange, in order to maintain a comfortable room temperature. The product needs to be intelligently controlled, and the design of the product needs to achieve not only air change and cooling. It can also be intelligently controlled based on personal experience. However, no external energy is used. It should have a reasonable structure, environmental protection, high utilization rate, intelligent operation, economy and low cost. The use of the product is not affected by the geographical area, the use of a wide range. The design makes full use of the clean resources available, reduces dependence on non-renewable energy sources, and realizes the theme of environmental protection. The products mainly use solar and wind energy, which are clean and sustainable new energy sources. There is no pollution to nature and zero emissions.

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(2) Principle Explanation The designed product mainly consists of an wind capture device, a waste heat recovery device, an air supply device, an air exhaust device, a solar energy storage device and an automatic control device. The wind catcher consists of a 360-degree air inlet and an induced fan blade. This system has been optimized and improved from the traditional wind catcher, which mainly uses two methods: direct introduction of natural air and forced ventilation by a fan. On the one hand, the natural air is introduced through a 360-degree circumferential air inlet, which makes up for the shortcomings of the traditional one-way air inlet; on the other hand, the natural air drives the rotation of the vertical shaft fan blades, which drives the induced fan on the same shaft to introduce air into the duct, thus achieving zero energy consumption for air capture. The natural air catcher uses two routes of air intake; an additional fan without fan blades provides the required airflow when the wind is not sufficient. Waste heat recovery technology increases the temperature of the air supply; the cyclone accelerates mixing, efficient heat exchange and reduces the sense of blowing air. Solar panel power generation and energy storage, automatic control technology，indoor temperature can be adjusted according to actual needs，and remote control by the Internet, portable operation. And has the advantages of zero energy consumption, high efficiency and no pollution, reflecting the concept of sustainable development of environmental protection and energy saving. The main component of the waste heat recovery unit is the plate-fin heat exchanger, with the cold side being the cold outdoor air and the hot side being the hot indoor exhaust air. The fresh outdoor air flows evenly through the headers into each flow channel and convects with the hot air on the other side. The overall heat exchanger is arranged in a cross-flow arrangement to increase the heat transfer temperature difference and triangular fins are used to increase the heat transfer area of the two gases, improving the air-to-air heat transfer effect and increasing the efficiency of waste heat recovery. The indoor air supply unit uses multi-point air supply, each air supply outlet is a worm gear cyclone, compared to other air supply methods, the worm gear cyelone can achieve a good mixture of fresh air and indoor air in a smaller space range, improve the air supply temperature, and no obvious blowing sensation, increasing air supply comfort The exhaust unit consists of an exhaust fan mounted on a vertical axis fan blade shaft and a solar collector duct. The exhaust of the indoor air is achieved in two main ways. On the one hand, when the natural wind is sufficient, the vertical shaft fan blades rotate and drive the exhaust fan on the same shaft to work to exhaust the indoor air; on the other hand, the air absorbs the solar radiation heat in the solar collector ducts and is discharged along the duets to the outside under the effect of density difference.’ Solar energy storage device, as the northern region has abundant solar energy resources, in order to achieve the use of renewable energy, this system introduces a solar energy storage device to provide electricity for the bladeless fan and the automatic control module.

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Automatic control device In order to achieve the stability of indoor air exchange and enhance the comfort of air supply, this system introduces an automatic control device, which consists of measuring points in the air duct，programmable logic controller (PLC), automatic switching regulator, PI regulator, etc. The solar battery provides energy for this device

3. Equipment Operation and Evaluation- (1) Prototype operation Based on the design principle, the prototype was assembled using existing components and other materials in the laboratory, as shown in Figure 1. The prototype shows the design principle very well and can operate stably and achieve all the design functions. Of course, due to the manual assembly and the fact that they are all non-standard components, the reliability does not reflect the advantages of the design.

Fig. 1 Product prototype The prototype achieves indoor-outdoor control to reduce the indoor temperature，and is wind- less and energy-free. The intelligent control is powered by solar panels, which truly achieves zero energy consumption and emissions. Based on the price of components and other comprehensive information, the estimated cost of the product is $500 for a space of about 100m2and $700 for a space of about 200m’. From design to application, the product is in line with the concept of low carbon and environmental protection design.

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(2) Application evaluation and analysis The design achieves zero energy consumption, high efficiency and pollution-free premise for air exchange, reflecting the concept of sustainable development. The design is mainly suitable for ventilation in winter in areas where radiators are used for heating. For areas that do not use air conditioning to cool down in the summer, this system can also maintain relatively low indoor tem- peratures and reduce the dissipation of cold air while satisfying air exchange. On the one hand, this design provides fresh, clean air to the room, reduces the concentration of CO2 and various harmful substances in the room, ensures fresh indoor air and gives people a healthy and comfortable living and working environment; on the other hand, the temperature difference between the exhausted dirty air and the air introduced into the room is used to exchange heat between the two gases while carrying out air exchange, in order to maintain a comfortable The room temperature is maintained at a comfortable level. It has many advantages such as portability, wide range of application, automatic plus manual, long service life, small size, environmental protection and adaptation to the environment. In line with the current national policy of low carbon, green and energy saving, and to meet the needs of most people, the device adopts a self-sufficient working system, using external wind and solar energy and other recyclable resources to meet the requirements of environmental protection.

4. Conclusion This paper presents a low carbon and environmental protection design solution, taking an example of an ordinary appliance exhaust system for everyday life. The design product not only achieves air exchange and cooling. It can also be intelligently controlled based on personal experience. No conventional energy is used. The design concept is structurally sound, environmentally friendly，highly utilization, intelligently operated, economical and cost effective. In addition, the product can be used in a wide range of applications, regardless of geographical location. The advantages of the low-carbon and environmentally friendly intelligent air exchange device are illustrated by the presentation of the prototype and the design simulation diagram. The design solution has been developed for air exchange units only, introducing a low carbon and environmental design concept. It is in line with the goal of a carbon neutral economy and meets the need for energy saving and emission reduction. There are many similar designs in life that can be promoted and developed, offering a variety of possibilities to promote the creation of an economical society in China, and sustainable development.

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