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A Good Time for Solar Air

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A Good Time for Solar Air SOLAR THERMAL SOLAR AIR COLLECTORS A good time for solar air The vehicle paint shop Solar air heating makes economic sense. Whether for heating production Friedrich Hoffmann in Germany operates a buildings, swimming pools and sports centres or for drying processes of all 40 m² air collector system consisting of Jumbosolar kinds – highly efficient collectors, in combination with the current good collectors from Grammer financial support situation, guarantee short amortisation times for larger Solar. Per year, around 20 MWh of solar heat constructions and for process heat applications. are used for the painting process and the heating of the building. or Johann Bauer every hour of sunshine is worth increase possible of up to 60 Kelvin with a volume Photo: Grammer Solar money. Since 2014 he has used a 143 m² solar flow of 30 m³ per hour and per square metre of collec- Fair collector system for drying wood chips at his tor area. The nominal output of the plant is 95.9 kW. premises in southern Germany. Up to 3,000 m3 can The regulation strategy, which is designed to achieve be processed in the drying plant per year. The drying maximum solar yield with minimum operating costs, process increases the heating value and thereby also includes regulation according to temperature differ- the market value of the wood chips. The dehydration ence, the creation of a constant air volume flow of the wood also inhibits the growth of poisonous through the measurement of pressure differences mould fungi and prevents water seepage. It also and powering via frequency converters as well as the minimises the risk of spontaneous combustion, due regulation of the external air according to humidity. to biological degradation processes. “Today, my plant achieved around 40 °C drying The warm, relatively dry air captured by the solar air temperature with a low water content for three roof is forced through the stack of wood chips from hours during the middle of the day at an outside below by means of a fan. The greater the temperature temperature of 7 °C and with light cloud cover”, Bauer increase achieved by the collectors, the smaller the was satisfied to report on a day in December. Accord- necessary volume flow and therefore the energy con- ing to Grammer Solar, through efficient collector tech- sumption of the fan. Bauer uses an air collector sys- nology and optimisation of the speed of the air in the tem of the type Grammer GLK from Grammer Solar, system, the use of additional energy can be reduced Amberg, Bavaria. The system uses highly efficient to around 3 % of the solar heat yield. The heating glazed collectors and makes possible a temperature value of the biomass is also considerably increased. 52 Sun & Wind Energy 1/2015 In comparison to passive convection drying by open storage without the use of any additional energy, the heating value of 100 t of moist wood chips can be increased from 170 MWh to 250 MWh through the use of 1.3 MWh of electricity. This represents a gain of more than 60 times the energy input. According to the manufacturer, an air drying system pays for itself at current prices in 7 to 10 years without any subsidies. The figure for Bauer’s plant is well below this, as it was supported by the Federal Office for Economic Affairs and Export Control (BAFA) as part of a German market stimulation programme in the category solar process heat. Systems with between 20 m² and 1,000 m² of gross collector area are subsidised at up to 50 % of the net investment costs. The vehicle paint shop Friedrich Hoffmann in Sundern, North Rhine-Westphalia, was able to profit from the BAFA support for process heat when they built their air collector system in July of last year. 40 m² of JumboSolar collectors from Grammer Solar will now provide around 20 MWh of solar heat annually. These will mainly be used to pre-warm the fresh air for the painting process. At times when no paint spraying is taking place, the building will be warmed using solar heat in order to prepare the com- ponents for painting. The nominal output of the system is 27 kW; the volume of solar warm air is around 1,400 m³/h. Heating costs reduced up to 90 % The Canadian manufacturer Enerconcept has already been producing systems for solar air heating since 1998. The company’s air collectors – including the Lubi made from polycarbonate, the facade system Unitair made from metal and the Luba GL for roof mounting – are certified by CSA (Canada), SRCC (USA) and BAFA (Germany). Since October 2014 Enerconcept has been part of the Canadian heating technology company Aeronergie, which made the purchase in or- der to extend its portfolio to include solar air. Accord- ing to the company, there are already many large projects for industrial companies and businesses in planning or currently being realised, in which the air collectors from Enerconcept will be utilised. “The merger of the companies Enerconcept and Aeronergie allowed us to offer complete packages to industrial companies with the help of which they can reduce their heating costs by 60 to 90 %”, explains Enerconcept’s former Managing Director Christian Vachon, who is now responsible for the areas of busi- ness development and R&D at the Aeronergie group. “The industries concerned are those that require large quantities of fresh air and air for combustion. We guarantee the savings made through our installations and continuously monitor the results.” Within the projects, the Enerconcept collectors are coupled with further energy-saving measures, for example with cross-flow heat exchangers, air-curtain door installations, the use of waste heat from Solar Edition 53 SOLAR THERMAL SOLAR AIR COLLECTORS The manufacturer of heavy construction plant components RY Beaudoin in Victoriaville, QC, achieves a reduction in heating costs of up to 90 % with its 225 m² wall of Lubi collectors in combination with further measures to increase efficiency. Photo: Enerconcept/Aeronergie compressed air systems as well as the installation of of heavy construction plant components RY Beaudoin intelligent control modules and volume flow regula- in Victoriaville, Quebec. An area of 225 m² of Lubi tors. “With solar air alone, the costs for air heating collectors was installed on the facade of the compa- can be reduced by 15 to 35 %”, calculates Vachon. ny’s production building and combined with a pack- “Tailor-made packages provide the companies with age of measures as described above. In the northern energy savings of up to 90 %.” Canadian town of Whitewater , Yukon, Aeronergie has Since the end of last year, one of the companies proved that air collectors can provide good service, to profit from savings of this size is the manufacturer even close to the border with Alaska. There, 120 m² of Lubi collectors supply a car wash with warm air. In addition to the solar air for drying and dehumidifying processes, the operator of the business uses water-based solar collectors to heat the wash water. Collectors eligible for support In Germany, the heating systems producer GoGaS Goch of Dortmund has held the exclusive licence and approval for the use of Lubi collectors since 2013. Also since this time, the collectors have had a Solar Keymark, having been tested by the Fraunhofer ISE, and are therefore approved for government support in Germany. “We would like to equip all of Germany’s production buildings with the Lubi”, says GoGaS Managing Director Heiko Schneider. “The walls of the 300,000 industrial buildings in Germany offer many millions of square metres of currently unused space. This colossal area has a gigantic and previously unexploited energy potential.” The concrete company Weber Betonwerk in Gollhofen, Bavaria, already benefits from a 75 m² Lubi façade. The solar air system is used to heat a new manufacturing hall and to help with the drying of concrete. When the sun does not provide enough heat, the system is automatically supplemented by two gas-fired air heaters each with an output of 35 kW and a total air throughput of 7,000 m³/h. The com- plete solar energy system was installed in only three days. According to Heiko Schneider, the energy costs saved by the new installation amount to € 1,950 54 Sun & Wind Energy 1/2015 annually. “Our products help companies to reduce operating costs and to protect the environment”, explains Schneider. Thanks to this positive experience, new solar projects are already being planned at Weber. The company wants to equip further production halls with air collectors. Cooling with solar air The Canadian solar air pioneer Conserval has now made its SolarWall collectors usable for the cooling of buildings for the first time. “Our invention is based on a transparent collector and uses the well-known phenomenon of radiation cooling at night, with the help of which the air can be cooled to below the ambient temperature between sunset and sunrise”, explains CEO John Hollick. “We call the system NightSolar and we connect it with the pre-warmer of the HVAC system.” The system works around the clock. During the day, heat is generated in the same way as with a con- ventional solar wall system, whilst the collectors also shade and ventilate the roof, thus reducing the build- ing’s air conditioning requirement by half. The heat can either be diverted or used for water heating or for industrial processes. At night, the same collectors cool the air to up to 5.6 Kelvin below the temperature of the surroundings, according to the manufacturer. In the months when heating is required, the air is warmed by the air collectors during the day before it enters the HVAC unit.
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