Introduction: Cheap Solar Air Heater
Hello everyone! My name is Gennadiy, and I live in the sunny city of Odesa, Ukraine.
Summer is ended and autumn is coming. Beautiful time, but a little cold. If you want to warm yourself with minimum cost - come with me and let's try to do a 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 into 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 the 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 a cut-off disc.
Step 3: Assembly
I have window glass from broken double-glazed windows. This is very cheap. Dimension of glass gives a dimension of the case of solar heater. Maybe your glass is different. Don`t worry, just adapt the dimension of the case for your glass.
Assemble the body from the board and plywood.
Lay the film (hydro barrier).
Install spacers thick as 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 aluminum 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 the electric fan to the inlet pipe. Connect the wire to the temperature controller and adjust on/off parameters.
Step 4: Tips
If you want a higher temperature, check this:
Seal and insulation all and everywhere. Inner temperatures are growing without hot air losses.
A short path of hot air is better.
Higher fan rate = lower temperature on out, but the efficiency of our system is higher. If you want to make it warmer at the exit - decrease the power of the fan.
Take cold air from above, exhaust hot air to below. Air mixes and the temperature will be more even and comfortable.
The main rule is fewer turns - fewer losses. There is two variant of the ducting path within the collector - "snake" and "snail". Snake is better when the form of the case is a rectangle, and the snail is 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's 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, the temperature is extremely high. We need the protection of our collector from direct sunlight. Close him by the material of house coating (in my case - vinyl siding)
Step 5: More Cheaper?
No problem. Don`t pay for an electric fan, take an old kitchen cooker hood. Good power, low noise, dust filtration, speed selector, even illumination - all of this is perfect for us. Try it.
Step 6: Summary
- Cost of all system less than 100 USD.
- Heating with a solar heater is cheaper than heating a standard electric air heater up to 10 times.
- Assembling needs just beginner level and minimum tools.
Step 7: Safety
Safety first! Don`t forget about this.
If you work with voltage higher, than 12v - be careful! Invite a qualified electrician for wire 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 is very heavy. Installing it carefully.
Do not be afraid to try and you will succeed. Good Sun to all!
Second Prize in the
Solar Contest 2017