Using hot air in conservatory

[David]

Has anyone tried pumping the hot air form the top of a conservatory into the floor ? I am planning to put in a thick concrete floor above insulation (polystyrene ?) and am thinking about laying 4 or 6 inch drainage hose in the concrete. Then with a couple of fans, piping the hot air from the roof apex down under the floor. The idea is to use the concrete pad as thermal storage, keeping the conservatory warmer on marginal evenings. It may still be necessary to vent some or most of the hot air on hot days, but the system could be useful for some of the year. The fans could be thermostatically controlled so that if the air temp rose above say 22C they start to store the excess heat. Anyone have any experience with this ?

[kitchenman]

I have been pumping the hot air from my conservatory into the kitchen for some years. I use an old cooker hood fan & 100mm ducting, there are 2 thermostats, when the air in conservatory is over 25C the fan starts, when the temp in the kitchen is 22C the fan stops. The conservatory faces east so misses out on max sun but works well even in the winter.

[NickW]

Read alt.solar.thermal

Plenty of good ideas on there. Search for 'solar closets'.

Nick

[IMM]

Good idea. It is best to have ducting from the conservatory into the loft and have a grill in the ceiling over the hall. Then the hot air can reach many parts of the house. You could also have grills in all bedrooms, if enough heat is generated. All easy, and apart from a cheap fan, nothing to run.

You can use a conservatory to cool a house. Hot air in the conservatory rise up and out through an open roof window. This bring air in from the house, which is replaced by cooler air from the north side of the house (best have the intake grill under vegetation to ensure it is cooler. So hot air can move air bringing into cooler air. All totally free to run and only some thought and ducting.

[IMM]

Good idea to store heat for later use. But will the sun be playing on the conservatory floor storing heat in the thermal mass anyhow? Heat stored further down the concrete slab may not rise into the room above in time to be useful. It is called admittance. Have tiles on the conservatory floor or better still have slate tile which have a very high admittance value.

When installing ducting under floors with air running through beware of condensation inside. They are fine in dry climates, but in the damp UK? Also have fine mesh grills to stop rodents and insects crawling through and if possible access to clean the ducting.

[Simon Avery]

Hello David

Interesting idea. But, ime, the concrete pad (& paving stone laid on top) in my conservatory was ample thermal store by itself - was still too hot to walk barefoot several hours after the sun went down.

For others it may be difference, I guess it's very dependant on position of C, geographical position, type of C (glass, poly, double or triple poly etc), size, ventilation and so on.