Heat transfer control question

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#2921516 1-Jun-2022 17:58

timmmay:

tweake:

try to put the outlet away from the door and windows as you can and the intake away from the fireplace a bit.

Wouldn't the intake be as close to directly above the fire as possible, in order to gather maximum heat for distribution?

the trouble is you also pick up smoke etc as well. the air at the ceiling is hot enough that it doesn't matter all that much.

secondary thing is not to cool the chimney to much (as it will suck air past it) otherwise you will have more soot etc build up in it. you want to take the heat from the room and not straight off the chimney. the other thing is you don't want a low air pressure area right next to the fireplace as that will try to draw air down the chimney and out of the fireplace air inlet.

so keep the intake away from the fireplace, let the return air come back in and mix, and get picked up again.

andrew75

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#2921542 1-Jun-2022 18:59

My intakes about 1m away from the chimney. Works well. No issues with smoke/soot.

timmmay

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#2921562 1-Jun-2022 19:55

tweake:

the trouble is you also pick up smoke etc as well. the air at the ceiling is hot enough that it doesn't matter all that much.

secondary thing is not to cool the chimney to much (as it will suck air past it) otherwise you will have more soot etc build up in it. you want to take the heat from the room and not straight off the chimney. the other thing is you don't want a low air pressure area right next to the fireplace as that will try to draw air down the chimney and out of the fireplace air inlet.

so keep the intake away from the fireplace, let the return air come back in and mix, and get picked up again.

Interesting. That might apply more to open fires? I used to have one of those standalone fires, but got rid of it and got a heat pump. Just removing the fire and the chimney made the place a lot warmer when there was no heating on, a big hole in the ceiling doesn't help keep heat in. Heat pumps are effective and is much nicer in densely packed cities.

tweake

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#2921571 1-Jun-2022 20:36

timmmay:

tweake:

the trouble is you also pick up smoke etc as well. the air at the ceiling is hot enough that it doesn't matter all that much.

secondary thing is not to cool the chimney to much (as it will suck air past it) otherwise you will have more soot etc build up in it. you want to take the heat from the room and not straight off the chimney. the other thing is you don't want a low air pressure area right next to the fireplace as that will try to draw air down the chimney and out of the fireplace air inlet.

so keep the intake away from the fireplace, let the return air come back in and mix, and get picked up again.

Interesting. That might apply more to open fires? I used to have one of those standalone fires, but got rid of it and got a heat pump. Just removing the fire and the chimney made the place a lot warmer when there was no heating on, a big hole in the ceiling doesn't help keep heat in. Heat pumps are effective and is much nicer in densely packed cities.

open fires are so inefficient i doubt anyone would bother using a heat transfer system with one.

thats the problem with open fires, they are a big draft. not surprised its far better with it removed.

timmmay

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#2921581 1-Jun-2022 20:52

Mine wasn't open, it was a standalone burner with a chimney going up through the ceiling and roof. Fairly modern.

tweake

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#2921740 2-Jun-2022 10:54

timmmay: Mine wasn't open, it was a standalone burner with a chimney going up through the ceiling and roof. Fairly modern.

i'm surprised it made that much difference. it must have been leaking a ton of air. most chimneys are open at the ceiling at the heat shield. these days you get eco versions which seal that.

just shows every house is different.

JayADee

2148 posts

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#2922588 4-Jun-2022 13:25

tweake:

timmmay: Mine wasn't open, it was a standalone burner with a chimney going up through the ceiling and roof. Fairly modern.

i'm surprised it made that much difference. it must have been leaking a ton of air. most chimneys are open at the ceiling at the heat shield. these days you get eco versions which seal that.

just shows every house is different.

Our stand alone is only just over a year old. It has the heat saver type flue (same as eco). Explanation in the link. I thought our old stove was pretty good until we got this one. This one will burn one piece of wood at a time; apparently the flue needs cleaned every 2 years and it pumps out heat if you want it to but you can also keep the temperature pretty low by having very little wood in it. I love it. It was worth all the pain of knocking out the old concrete slab, dragging out the old one, putting plans in to council and getting consent. We have heat pumps too but I find them a 'cold' heat if that makes any sense.

http://www.nelson.govt.nz/environment/air-quality/burn-bright/heat-saver-flues/

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tweake

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#2922639 4-Jun-2022 13:50

JayADee:

We have heat pumps too but I find them a 'cold' heat if that makes any sense.

actually yes it makes sense. at the risk of being insulting, thats often due to people simply not heating their houses properly. typically not having the heating on long enough and also allowing the house to cool back down.

a fireplace puts out higher temps and radiant heat, which heats you directly. so you feel hot directly from the fireplace.

where as heat pumps heat the air, to heat the house, and the house then heats you. but if you don't run it long enough the walls etc of the house do not get up to temp, and that makes you cold. it takes a lot of energy and also time to heat the house properly. unfortunately thats the drawbacks of having an old home or a newer home which is still a low performing home. hence the new insulation rules due to start in a few months time.

timmmay

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#2922848 5-Jun-2022 10:54

I agree mostly with @tweake. Our house is old but well insulated and ducted heating, and we find that once it's heated through it's easier to heat and more comfortable than if heating is turned on occasionally. Our heating is turned on at 3pm, earlier if it's cold, and turns off when everyone goes to school / work. The house never drops below about 19 degrees because it's heated through and heated often.

tweake

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#2922869 5-Jun-2022 12:18

timmmay:

I agree mostly with @tweake. Our house is old but well insulated and ducted heating, and we find that once it's heated through it's easier to heat and more comfortable than if heating is turned on occasionally. Our heating is turned on at 3pm, earlier if it's cold, and turns off when everyone goes to school / work. The house never drops below about 19 degrees because it's heated through and heated often.

yes absolutely. air takes very little energy to heat, but mass takes a huge amount. by not letting that mass cool down to much makes it easier to get it back to temp, which in turn makes the house warmer. that thermal mass heats the house even when heating is off. plenty of stories around of people complaining house is cold the instant you turn off the heat, and thats why. the house is actually cold and but they are in warm air so they feel warm. turn off that warm air and you feel how cold the house is.

mass takes time to heat up, you need to run heating long enough for that to happen.

the bonus is heat drives moisture away and a dry house is easier to heat.

JayADee

2148 posts

Uber Geek

#3027960 27-Jan-2023 17:32

Hi,

As an update we just got the Simx 1 room heat transfer installed a few days ago and asked for extra blanket insulation to be wrapped around the ducting due to it being installed in an uninsulated space (under a tile roof, above the ceiling insulation).
I'll let you know how it goes after a few months of winter.

The thread was very helpful, thanks.

tweake

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#3027973 27-Jan-2023 18:17

JayADee:

Hi,

As an update we just got the Simx 1 room heat transfer installed a few days ago and asked for extra blanket insulation to be wrapped around the ducting due to it being installed in an uninsulated space (under a tile roof, above the ceiling insulation).
I'll let you know how it goes after a few months of winter.

The thread was very helpful, thanks.

i just hope you have the return side installed. i think simx, the last time i looked, its one line in the manual, which frankly is better than most i've seen.

failure to install the return results in a lot of heat wasted but also can cause smoke to be sucked out of the fireplace, fill the house with smoke, and if don't have smoke alarms that could kill you. many people have had close calls.

JayADee

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#3028139 28-Jan-2023 06:20

What is the 'return side'?

tweake

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#3028160 28-Jan-2023 09:56

JayADee:

What is the 'return side'?

return side is the air path back to the heating source. in this case from the bedroom back to where the fireplace is.

the simplest is trimming the bottom of the doors. you can get door vents which install in the door. or a outlet on the ceiling with duct going back to the lounge or as a jumper duct going over the door and into the hallway. of course you need a jumper etc over the hallway door.

JayADee

2148 posts

Uber Geek

#3028642 29-Jan-2023 07:34

Oh thanks. Yeah it isn't an issue we took that into account planning it. Vast majority of the time the doors between the inlet and outlet are open so it will be an open circuit so to speak. :)

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