Heat transfer around the house

[David WE Roberts]

Quick post because I keep forgetting to post this query.

Back of the house faces south and is hot. Front of the house (NSS) faces north and is cool.

It seems sensible to be able to move warm or cool air between rooms as required.

Specifically, in the summer if the back of the house is too hot, to move cool air from the front to the back. In winter, when the front room is too cool but the back room has been heated by the sun, to be able to move warm air from the back of the house to the front.

The logical flow is from the ceiling of the back room to the floor of the front room. Either: (1) Cool air from the floor level of the front room flows out of the ceiling of the back room, falling and lowering the room temperature or (2) Warm air from the ceiling of the back room flows out at floor level in the front room, rising and warming the room.

All well and good so far, but now the implementation. Ceiling to ceiling should be O.K. assuming the joists run in the right direction. Running from the ceiling to the floor level is the problem. There needs to be some concealed ducting. Just doing ceiling to ceiling would lose the benefits of convection unless you had an absurdly powerful fan. A quiet fan would be a great bonus.

Anyone done this? I saw a wierd attempt on TV where some people were playing at being 'green' by putting up a wind turbine, installing wood burning stoves etc but they had a crazy zigzag run with loads of white extractor fan piping going all over the loft and it didn't seem to work very well (if at all).

Cheers

Dave R

[MM]

I have exactly the same situation as you - south facing warm side (kitchen) and north facing cold side. Even on very cold days in winter, if the sun is out the kitchen gets a fair bit of warmth through the patio doors. I'll see what responses this thread gets.

MM

[Dave Liquorice]

Yep.

You won't get convection bewteen the two. Cold air sinks, it will not go up the duct by itself. Similary hot air rises it won't go down the duct by itself.

Air pressure differences due to the wind outside might get a flow but the direction would be dependant on the wind direction which might not be the one you want.

So it's going to have to be assisted, large and slow is good for quiet. A couple four inch PC case fans run on an adjustable voltage supply so you can control the speed may well provide enough flow with very little noise. Of course there has to be a circulation route for the air and you may find you also install a speaking tube. B-)

[David WE Roberts]

To clarify - the convection takes place in the room after the air has been introduced. So you release warm air near the floor to rise, and cold air near the ceiling to fall.

The air transfer between the rooms will have to be fan assisted.

My main problem is the ducting ceiling to floor in the cool room to allow the air to be collected or delivered at the correct point.

[Harry Bloomfield]

There would be some convection flow, with a duct starting in the ceiling height of a warm room, if the duct then passed into the cold room then went down to the floor.

Rather than passing air between the rooms, might not a pumped wet system work? Something like a radiator at ceiling height in the hot room collecting heat, coupled to a second radiator in the cold room via a slow running pump.

Other than that, a slowly rotating heat wheel - large mass of alloy wheel collecting heat in the the warm room, then rotating (with the heat) into the cold room?

[The Natural Philosopher]

I am relatively open plan..very leaky doors. Kitchen in the north, aga!

living room in the south. Windows!

[Steve Firth]

The response it gets is the same as with any thread that you make. You advocate beating children and you claim that this is good for them. How many children have you had and did knocking them about a bit do any good for them or did they end up like you?

[David WE Roberts]

I think you need a large temperature gradient to transfer heat effectively using a wet system, or a very very large surface area. Moving air just a few degrees warmer, however, should make a difference as long as you can move a reasonable amount of air.

Er, yeah, and what diameter wheel did you have in mind? And if it is to transfer heat from floor to ceiling or vice versa it would have to be vertically mounted. Be cheaper to do almost anything else :-)

[Hugo Nebula]

Summer cooling is relatively easy; open windows on the ground floor of the cool side and on the first floor of the warm side. The natural buoyancy of the warm air will create a stack effect, pulling in cooler air at the bottom. Not sure if the process can be reversed to heat the lower level.

Google 'passive stack ventilation'.

[David]

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