Morbo said:
Keep in mind, the roof space is way smaller than your living space, so I cannot imagine, within 8 or so daylight hr it gets enough heat to warm up your house. In Melbourne is not much sun in winter...
In Melbourne the solar radiation figures are 7.1MJ per m2 in June.
A five star house in Melbourne is 150MJ per m2 per year, so with 150 days of heating that is 1MJ per m2 per day. So it is possible to heat with a solar air heater given that you can collect about 1/4 of the global solar radiation. A better predictor of output from a solar air heater r is the hours of strong sunlight, and as you say in Melbourne there are many overcast days, during which a solar air heaterr doesn't help much. I should do the calculations comparing the heating cost savings of increased insulation vs solar air heater.
I do have two solar air heating systems on my house. I do like them and the heat they dump into the south of the house, but the payback time is somewhat longer than is usually advertised. For my house they provide 10-20% of the heating.
Posted Saturday 11 Apr 2015 @ 10:22:10 pm from IP
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