How can i calculate the heat gained by a sunspace (with given dimensions and location info.)?

Question

I don't need softwares because they are too complicated. I have no time to learn it. If you can tell also to calculate the heat gain from trombe walls and any other passive solar systems i'll be very glad.

Answer 1

The solar radiation impinging on a plane normal to the direction of the Sun is 1,366 W/m^2 on a clear day. Some use a constant of 1,251 W/m^2 to account for atmospheric attenuation and reflection.

This amount varies with latitude, time of year, and time of day. When you begin to work out solar heating for a building, you must also take the orientation of the building into account. The calculations for the roof and each wall will be different.

You can avoid dealing with time-of-day variations by multiplying the constant by 2/π ( ≈ 0.6366)and multiplying by 12 hours to get a figure of 9.5569 KWH/day/m^2.

You can also get an average for seasonal variations by integrating for the average angle-of-incidence for your latitude. I haven't done that derivation, so cannot give you a factor.

Two things remain to be accounted for: atmospheric attenuation for other than zenith conditions, and overcast. I would "fudge" the attenuation factor by using 2/π again, and you may be able to get a "clear day percentage" from your local weather bureau.