Design and development of Solar Thermal Air Heater

Project Title

Design and development of Solar Thermal Air Heater

Project Area of Specialization Mechanical EngineeringProject Summary

Conventional electric or gas heaters use costly electricity, burn fossil fuels, reduce oxygen, recirculate same air and are highly unsafe as evident from many accidents caused by these heaters. Post COVID-19 ventilation standards recommend use of more fresh air to reduce the risk of airborne diseases.

The proposed “Solar Air Heater” will heat the air by absorbing the solar energy in an absorber plate and also store thermal energy in a phase change material (PCM) filled base working as thermal energy storage (TES) during peak sun hours. The glass cover above the absorber will provide greenhouse effect to trap more solar radiations. Different fins, baffles, ribs, black paints and coatings will be employed to enhance the solar radiation absorption and heat transfer to air passing through the air heater. The blower for air supply will run on solar photovoltaic energy. Solar energy collected by absorber plate is used to heat air during day and to store energy for night.

Prototype with sensors and control system will help us analyze the performance to develop low cost solutions for space heating. Supply of fresh warm air will reduce the spread of airborne diseases like COVID-19. The use of free solar energy will reduce the energy bills substantially and also there are no hazards of combustion products in the air. Low humidity issues linked to electric heaters are also addressed by the use of fresh air. It is very useful for remote areas away from national grid and can improve living of the poor and reduce wood burning, CO2 emissions and severe smog issues.

The solar heater will consist of clear glass panel and finned metallic sheet as absorber on top of a glass fiber-reinforced container which houses the PCM and is insulated from the outside. All components are fastened to a metallic frame as shown in Fig. 1. The clear panel admits sunlight, and an absorber plate (duly painted/ coated for better absorptance) captures the sun’s energy. The air around the absorber warms, expands and rises, creating a convection. Fresh air enters through the lower vents, is heated by the absorber, rises to the upper vents, and is supplied to the space. Energy stored in the thermal energy storage can be used for the night time operation.

Figure 1: Sketch of Solar Air Heater

Project Objectives

All commercial and residential buildings need ventilation air for the human health and comfort. In winters huge amount of money is being spent by using the conventional heating systems, the solar air heater is good for health and an economically feasible alternative. Our plan for commercialization is outlined below:

• We shall manufacture a fully functional model of the solar air heater and prepare a comprehensive performance report after its testing.
• In parallel we shall do extensive market survey to get the prices of the materials and components used and explore all the cheap alternates of them.
• Based on this knowledge we shall prepare a comprehensive business plan to produce solar air heaters on mass scale.
• We shall do the marketing of our business plan through social media, industrial open house, university incubation and commercialization office, etc. to attract a suitable business partner having space and facilities for the mass production and commercialization the solar air heater.

Project Implementation Method

Keeping in mind the acute shortages and ever rising prices of electricity and natural gas, solar air heater has the great selling potential. Now a days people are highly conscious about the energy bills, environmental pollution, health hazards, clean air and spread of air borne diseases. All these terms can be our marketing and selling key points. People are hugely investing in high-rise buildings where the lower floors and interior spaces are always at lower temperatures compared to the sun facing facades. Our solar air heating can be a very attractive long-term solution for all those builders, developers and building owners who want a sustainable solution for the ventilation and heating of their buildings.

Solar air heating is a one-time investment as there is no operational cost, so it has the   potential to attract the customers. The estimated price depends on the type of plates and material used on the solar air heater, approximately Rs. 20,000 will be the sale price for a medium size unit. It is better than conventional heaters in terms of safety and health concerns and also in terms of operational costs.

Benefits of the Project

1. Reduction in electricity and gas bills.
2. Highly safe and free from gas leakages, burning, explosions or electric shocks.
3. Sustainable solution running on free solar energy.
4. Environment friendly as there are no emissions.
5. Almost no operational cost and requires very less maintenance.
6. Working fluid is air which is available free of cost.
7. Easy installations and no specialized workmanship are required.
8. Reduces chances of airborne disease spread.
9. Increased fresh air supply improves the health of the occupants.
10. Reduction in CO2 emissions and greenhouse gases in the atmosphere.
11. Reduction in diverse health problems, e.g., pulmonary, respiratory, and skin diseases.
12. Reduction in burning wood or agricultural crop residues which causes “smog” which is a form of visible air pollution.

Technical Details of Final Deliverable

We are working to design and develop an experimental setup of solar thermal air heater with thermal energy storage for space heating. Solar energy collected by replaceable absorber plates of different materials, geometries and fin arrangements, is used to heat air during day and to store energy for night.

This setup will be used to demonstrate development of low cost, sustainable, renewable energy solutions for space heating in the remote areas to help improve the health and living of poor people and reduce the sever environmental issues like, deforestation, smog air polution, fossile fuel burning, CO2 emissions, etc.

The solar heater will consist of clear glass/ plastic panel and corrugated/ finned metallic sheets as absorber plates on top of metallic/ glass fiber-reinforced container which houses the phase change material (PCM), all fastened to a wooden/ metallic frame properly insulated from the outside. The clear panels admit sunlight, and an absorber plate (duly painted/ coated for better absorptance) inside the collector captures the sun’s energy. The air around the absorber warms, expands and rises, creating a convection. Vents at the top and bottom of the collector allow air to circulate through it. Cool air enters the lower vents from the interior, is heated by the absorber, rises to the upper vents, and is supplied/ circulated to the space to be heated. Energy stored in the thermal energy storage can be used for the night time operation.

Final Deliverable of the Project Hardware SystemCore Industry Energy Other Industries Manufacturing , Others , Health Core Technology Clean TechOther Technologies Shared Economy, OthersSustainable Development Goals No Poverty, Good Health and Well-Being for People, Affordable and Clean Energy, Decent Work and Economic Growth, Industry, Innovation and Infrastructure, Reduced Inequality, Life on Land, Partnerships to achieve the GoalRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	80000
Stationery	Miscellaneous	10	200	2000
Printing	Miscellaneous	4	1000	4000
Overheads	Miscellaneous	1	4000	4000
Wood/ Steel for Frame	Equipment	2	2500	5000
Metal Plate for Absorber	Equipment	2	4000	8000
Glass Fiber Material	Equipment	1	1000	1000
Glass Panels	Equipment	1	500	500
Screws, Nut, Bolts, etc.	Equipment	100	20	2000
Paints/ Coatings	Equipment	2	1000	2000
Controller	Equipment	1	2500	2500
Thermocouple	Equipment	10	250	2500
Hygrometer	Equipment	2	1500	3000
Anemometer	Equipment	2	5000	10000
Copper Tubes	Equipment	5	500	2500
Fan/ Blower	Equipment	1	2000	2000
Wires and Cables	Equipment	10	200	2000
Photo Voltaic Panel 150W	Equipment	1	9000	9000
Solarimeter	Equipment	1	15000	15000
Natural Bee Wax (PCM)	Equipment	5	300	1500
Insulation Materials	Equipment	1	1500	1500