Introduction: Cheap Solar Air Heater
Hello everyone! My name is Gennadiy, and i live in sunny city of Odessa, Ukraine.
Summer is ended and autumn is coming. Beautiful time, but little coldly. If you want to warm with minimum cost - come with me and lets try to do cheap solar air heater.
My heater is made on the basis of an idea Glen and Ronny's Solar Heater Project 2007-2009, but adapted for my conditions and materials.
Step 1: Specifications
1. Operation: Off-season.
2. Total area: 3.4 m2.
3. Angle to the horizon: 90 degrees.
4. Direction to the south: South-South-West.
5. The total power of the fan: 120 W / h.
6. Overall performance of the fans: 300 m3 / h.
7. Total absorber area and duct material: Absorber: Galvanized sheet 2.4 m2. Duct: flexible aluminum ducting with a diameter of 100 mm, length of 20 m.
8. Coating: painted with high temperature black barbecue grill paint.
9. Heat carrier: Air.
10. Outputs from collectors: 2 to 100 mm.
11. Body: Pine board profile 200x30 mm, galvanized sheet, insulation - stone wool 50 mm, window glass 4 mm.
Step 2: Needed Materials
1. Flexible aluminum ducting 100mm, 10 pcs, and aluminum tape, 2 rolls.
2. OSB sheet 1250mm x 2500mm x 10mm. It is cut along to 2 parts, in my case need another small piece from the stocks is used.
3. Window glass 0,66m х 1,75 m, 4 mm thick, 3 pcs and sealing rubber for pressing glass to the body.
4. Heat-resistant black paint, 400 ml, 2 pcs.
5. Plastic pipe 110 mm, 2 m.
6. Bend 90 deg 110 mm for plastic pipes, 5 pcs.
7. Insulation pipe 110 mm made of expanded polyethylene.
8. Stone wool, 50 mm, 5 m2.
9. Temperature controller (Aliexpress)
10. Pine board, 0.03 x 0.2 x 4 m, 3 pcs.
12. Drill, screwdriver, angle grinder with cut-off disc.
Step 3: Assembly
I have a window glass from broken double-glazed windows. This very cheap. Dimension of glass give a dimension of case of solar heater. Maybe your glass is different. Don`t worry, just adapt dimension of case for your glass.
Assemble the body from the board and plywood.
Lay the film (hydro barrier).
Install spacers thick as a stone wool.
Lay the stone wool (rock wool, mineral wool, glass wool, etc.)
Cut the galvanized sheet and do "box in box".
Cut holes for pipes.
Install aluminium flexible ducting and painting with black paint.
Install the thermistor inside of ducting output.
Cover it with glass, pressing it through the rubber sealant.
Install the inlet and outlet pipes, make good thermal insulation on all his way in/out house.
Connect electric fan to inlet pipe. Connect wire to temperature controller and adjust on/off parameters.
Step 4: Tips
If you want higher temperture, check this:
Seal and insulation all and everywere. Inner temperature are growing without hot air losses.
Short path of hot air is better.
Higher fan rate = lower temperature on out, but effeciency our system is higher. If you want make it warmer at the exit - decrease power of fan.
Take cold air from above, exhaust hot air to below. Air mixes, and the temperature will be more even and comfortable.
Main rule is: less turns - less losses. There are two variant of ducting path within collector - "snake" and "snail". Snake is better, when form of case is rectangle, and snail good for square form.
If you are targeting an annual output - then you need to have the collectors at an angle equal to the latitude of the terrain. If you need summer output, then the angle of inclination should be reduced by 15 degrees. If you are targeting winter production (heating system support) - then the angle of inclination should be increased by 15 degrees. For example: for my city latitude of about 46 degrees, then at this angle it is necessary to put collectors in order to get maximum heat within a year. For summer use, the angle should be 46 - 15 = 31 degrees. And for the winter 46 + 15 = 61 degrees. These are the optimal values.
In summer, temperature is exteremely high. We need protection of our collector from direct sun light. Close him by material of house coating (in my case - vinyl siding)
Step 5: More Cheaper?
No problem. Don`t pay for electric fan, take old kitchen cooker hood. Good power, low noise, dust filtration, speed selector, even illumination - all of this is perfect for us. Try it. Really.
Step 6: Summary
- Cost of all system less then 100 USD.
- Heating with solar heater cheaper than heating standard electric air heater up to 10 times.
- Assembling need just beginner level and minimum tools.
Step 7: Safety
Safety first! Don`t forget for this.
If you work with voltage higher, than 12v - be careful! Invite a qualified electrician for wires connect.
Working on angle grinder - use safety glasses. Working with window glass - use gloves.
Never work himself - working with friends is faster and more fun. Also, assembled sun collector very heavy. Install it carefully.
Do not be afraid to try and you will succeed. Good sun to all!