Solar Air Heating Technology
SolarAir Heating Technology
SolarAir Heating Technology
Currently,the world is in the search for technology that allows the use ofrenewable and environmentally friendly sources of energy. The solarair heating is one of these technologies that allow man to tap anduse energy from sun in performing household and industrialoperations. The solar air heating systems also known as the solarwall technology is a renewable source of technology that is used tocondition or heat air for commercial buildings or industrial processapplication (U.S. Energy Information Administration, 2013).Initially, the solar air heating systems were used in pre-heatingventilation air, but they are currently applied in many areas,including maintenance of suitable temperatures in agriculturalbuildings and crop drying. Technology advancement has allowed thescientists to develop two types of solar air heating systems thatenhance efficiency in the air heating process. The non-concentratingcollector is a solar system that has a collector area equal to theabsorber area while a concentrator collector has an area of solarradiation that is larger than the absorber area. The solar airheating system generates environmental, workplace, and economicbenefits that cannot be achieved when using other sources of energy.
Howsolar air heating technology works
Thesolar air heating system is made of two parts, including the solarcollector and air distribution system. The solar collector is mountedon the wall of the building that faces the equator while thedistribution system is fitted in the building (Natural ResourceCanada, 2004). The solar air heating system is fitted with aperforated plate that serves as a solar collector, thus reducing theneed for using a glass cover as in the case of other types of solar.The system draws air through the holes found in the dark collectorplate where it is heated as it passes through and over the plate. Thewarmed air collects in the cavity that is found between solar systemcollector and the wall of the building. The warm air is then ductedinto the building. The plates of the solar collector exceed thewarmth of outdoor air by a few degrees, and this enhances efficiencysince there is minimal heat loss.
Figure1: Transpired plate for solar collector
Source:Natural Resource Canada (2004)
Alternatively,dampers can be installed in the canopy to permit the passage ofambient air directly into the building. With the use of moderntechnology, an automatic thermostat, which senses the level oftemperature in the outdoors, can be installed to regulate thetwo-position damper. The adjustable thermostat opens the damper whenthe temperature in the outdoors is warm (15 -20 0C), thus reducing the need to continue heating the room (NaturalResource Canada, 2004). The size of the solar heating system variesdepending on the desired rate of ventilation as well as the area thatis available to allow the installation of solar collectors. Differentsizes of the solar air heating systems are designed to achieve eitherof the tow objectives, namely solar collection efficiency andtemperature rise.
Figure2: The schematic diagram of a solar air heating system
Source:Conserval Engineering Incorporation, (2013)
Applicationsof solar air heating technology
Applicationsof the solar air heating technology are broadly classified into two,namely ventilation air warming for buildings and the process airwarming or heating. Air heating for the buildings is applied incommercial as well as residential buildings and industrial buildings(Natural Resource Canada, 2004). Both residential and commercialbuildings require ventilation air. The solar air heating system isinstalled in such buildings in order to preheat the air before itgets into the building. Ventilation air is first pulled by a unitthat handles the ventilation air, which then uses the conventionalductwork to deliver the air into the building. During the cold days,system preheats the ventilation air while the heater installed in theair handling section adds-up the remaining heat. However, the solarheating system has the capacity to provide sufficient heat energyduring the cool and sunny days. A bypass damper is usually openedduring summer in order to avoid the heat overload on the solarheating system, which ensures the ventilation air is heated to theoptimum level. In most cases, the solar heating system is connectedto the outdoor air where it collects and distributed it through theconventional ductwork.
Figure3: Multi-unit residential building fitted with solar air heatingsystem
Source:Natural Resource Canada (2004)
Industrialventilation is achieved by heating large amounts of outdoor air,which is then used to replace the air that is exhausted within theindustrial building. The air inside of the industrial building may beexhausted by automotive fabrication, welding, painting, and otherindustrial operations (Natural Resource Canada, 2004). However,industrial buildings are usually designed with wide and open areaswith a high ceiling that allows the installation of large solarheating system that has the capacity to replace sufficient amount ofair for the entire building. The air handling component that isfitted in industrial buildings is designed in a way that allows it tovary the quantity of outdoor air in a manner that leads to a constantflow of air. In case the industrial building does not have anexisting system for air distribution, the interior components of thesolar heating system should include an air recirculation system,constant-speed fan, and a distribution duct. The recirculation systemthat is incorporated into constant-speed fan plays the role of mixingthe warm indoor air with the cool air from the solar collector, whichhelps in maintaining a constant flow of air temperature intoindustrial building. The ratio of recirculation air to outdoor airfrom the solar heating system changes continuously in a way that isconsistent with the temperature of the outlet of the solar collector.The heated air is distributed within the industrial building throughperforated ducts that are located in the ceiling of the building. Theair from the ducts is often cooler compared to air at the ceiling,and this makes the ventilation air cool the ceiling, thus reducingthe reducing the loss of heat through the roof. The air then fallsand mixes with the air in the building.
Figure4: Solar air heating system for industrial building
Source:Natural Resource Canada (2004)
Thesolar air heating system provides optimum temperatures for processapplications. The solar systems used in the process applicationsoperate under similar mechanisms to the ventilation air heatingsystems. A perforated absorber is for the system is located in anarea that exposes it to the sun. Air is then constantly deliveredthrough the system collectors from where it is ducted into the intakeof the process. The air can also be heated using auxiliary heaters toensure that the desired temperature is achieved (Natural ResourceCanada, 2004). However, if the temperature is above the desireddegrees, all the air can also be bypassed the collectors. This systemis mainly used in drying agricultural produce because the heat energyfrom solar can be kept at low levels to avoid damaging the produce.
Benefitsof solar air heating technology
Theuse of solar air heating technology has three major benefits. First,this technology provides a sustainable environmental solution byreducing the rate of emission of greenhouse gasses into theatmosphere. Research shows that the solar heating system has thecapacity to displace between 20 % and 50 % of fuel consumption, whichdepends on the application and the size of the system (ConservalEngineering Incorporation, 2014). This implies that the solar heatingsystem provides a solution for climate change, which is mainly causedby emission of carbon dioxide from fossil fuels. In addition, thesolar heating system is made up of copper, polymers, steel, andaluminum, which are easy to recycle (Resch, 2014).
Secondly,the solar air heating technology enhances business competitiveness byreducing the cost of doing business and increasing efficiency (U.S.Department of Energy, 2013). The system reduces the cost of operationbecause fuel is generated from the sun and supplied efficiently intothe building free of charge once the system is installed. Inaddition, the system does not experience price volatility, whichmeans that businesses cab budget for fuel expenses in the long term.
Third,the solar air heating technology acts as a good source of employmentopportunities. According to Resch (2014) the solar air heating energyprovides higher paying jobs with compensation that is 13 % above thecompensation given to workers in other industries. It is estimatedthat this technology provides over 5,000 jobs in the United Statesalone. In addition, the systems are installation driven, which meansthat they should be outsourced. This increases the capacity of thistechnology to create more jobs.
Thedownside of using the solar air heating technology
Althoughthe solar air heating technology has a wide range of benefits, thereare three major drawbacks that reduce the capacity of businesses andowners of residential buildings to install the solar system.According to Resch (2014) the solar heating system requires a highinstallation capital with a low payback of about 4 to 8 years.Although the cost of operation is low compared to other sources ofenergy, the high initial capital hinders the use of this technology.Secondly, the solar plates and other components depreciate with time.The system is exposed to factors (such as ultraviolet radiations,temperature fluctuations, snow dirt, and rain), which increase therisk of deterioration. Third, the solar heating system lacksreliability and consistency because they rely on the constantabsorption of sunlight. This means that the solar plates cannotgenerate energy at night, which reduces their functionality (Bratley,2014). The combination of these challenges may at times outweigh thebenefits of solar air heating technology.
Thesolar air heating system generates environmental, workplace, andeconomic benefits that cannot be achieved when using other sources ofenergy. The main components of the solar air heating system includethe solar collector and air distribution system. This system isapplied in three major areas, which include the heating of air inresidential and commercial buildings, heating air in industrialbuildings, and process applications. The three main benefitsassociated with this type of technology include reduction ofenvironmental pollution, enhanced business competitiveness, andcreation of green-collar jobs. However, the use of solar heatingtechnology may be hindered by high initial cost of purchasing andinstalling the system, depreciation of system components, and lack ofconsistence in supply of energy.
Bratley,J. (2014). Disadvantages of solar energy. CleanEnergy Ideas.Retrieved March 14, 2014, fromhttp://www.clean-energy-ideas.com/solar/solar-energy/disadvantages-of-solar-energy
ConservalEngineering Incorporation (2013). How the Solar Wall technologyprovides fresh air and free heat. ConservalEngineering Incorporation.Retrieved March 14, 2014, fromhttp://solarwall.com/en/products/solarwall-air-heating/how-solarwall-works.php
ConservalEngineering Incorporation (2014). Solar Wall Air heating andventilation system. ConservalEngineering Incorporation.Retrieved March 14, 2014, fromhttp://solarwall.com/en/products/solarwall-air-heating.php
NaturalResource Canada (2004). Solarair heating project analysis.Toronto: Natural Resource Canada.
Resch,R. (2014). Solarheating and cooling: Energy for a secure future.Washington, DC: Solar Energy Industries Association.
U.S.Energy Information Administration (2013, May 29). Solar explained:Heating with the sun’s energy. U.S.Energy Information Administration.Retrieved March 14, fromhttp://www.eia.gov/energyexplained/index.cfm?page=solar_thermal_collectors
U.S.Department of Energy (2013, September 9). Industrial distributedenergy. U.S.Department of Energy.Retrieved March 14, 2014, fromhttp://www1.eere.energy.gov/manufacturing/distributedenergy/