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Thermal store vs. Ground Source
Thinking about Heat Recovery Ventilation.
If I put in the ducting for a whole house, with inlet and outlet,
surely it's just one step short of a central air conditioning system?
Since these heat pump based air conditioning units work for cooling AND heating,
isn't it just a case of putting one of these in series with the incoming fresh air?
If the exchanger is 70% efficient in recovering the heat energy in winter,
and does the equivalent for the air-conditioned cold air in the summer,
then the heater only has to top up the 30% in summer,
and the same for the cooler function in winter.
There are heat loss through the roof, etc. as well of course,
but we can probably end up using half the energy compared to a normal house.
Another optimisation idea is to use a thermal store (TS) water tank.
The cold mains water feeds into the TS tank, and goes onto the Domestic Hot Water (DHW) tank.
The coolant would circulate between the heat pump and the TS tank.
In summer, the coolant will be hot from the heat pump,
and the cold mains water will cool it down, which also means the water is preheated before going into the DHW tank. If the water gets too hot, it has to be dumped into the drain,
unless there is some other way to use it. A pressure release valve in case of steam.
In winter, the coolant will be ice cold from the heat pump, and needs to pickup heat.
Economy 7 over night (immersion element) with day time top up, solar panel by day, or good old gas boiler should all be easy to do. Remember we only need to top up, so we can use a smaller boiler.
Ground source heating needs land, and is expensive to lay the pipes. I think air source heat pump is non-sense: it doesn't work when it's cold!
If I can get this done for two to three thousand pounds, it will save energy in the long run,
and I can get rid of the radiators.
Any products that fit the bill?
If I put in the ducting for a whole house, with inlet and outlet,
surely it's just one step short of a central air conditioning system?
Since these heat pump based air conditioning units work for cooling AND heating,
isn't it just a case of putting one of these in series with the incoming fresh air?
If the exchanger is 70% efficient in recovering the heat energy in winter,
and does the equivalent for the air-conditioned cold air in the summer,
then the heater only has to top up the 30% in summer,
and the same for the cooler function in winter.
There are heat loss through the roof, etc. as well of course,
but we can probably end up using half the energy compared to a normal house.
Another optimisation idea is to use a thermal store (TS) water tank.
The cold mains water feeds into the TS tank, and goes onto the Domestic Hot Water (DHW) tank.
The coolant would circulate between the heat pump and the TS tank.
In summer, the coolant will be hot from the heat pump,
and the cold mains water will cool it down, which also means the water is preheated before going into the DHW tank. If the water gets too hot, it has to be dumped into the drain,
unless there is some other way to use it. A pressure release valve in case of steam.
In winter, the coolant will be ice cold from the heat pump, and needs to pickup heat.
Economy 7 over night (immersion element) with day time top up, solar panel by day, or good old gas boiler should all be easy to do. Remember we only need to top up, so we can use a smaller boiler.
Ground source heating needs land, and is expensive to lay the pipes. I think air source heat pump is non-sense: it doesn't work when it's cold!
If I can get this done for two to three thousand pounds, it will save energy in the long run,
and I can get rid of the radiators.
Any products that fit the bill?
0
Comments
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you could also investigate geothermal heat pumps, the cost is directly related to how deep any bore holes need to be but can be very efficient and cost effective if you live in a suitable area.0
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you would be looking at a lot more than a few thousand pounds to do that....GSHP`s are only good if they are spec`d correctly, same as ASHP`s..... a typical borehole of 100 metres deep will yield about 4.5 - 5 kW and will cost £5.5K to drill....then there is the heat pump to buy and install, so in the region of £10K upwards, My A2WSHP works very very well in minus 10 degrees..... is guaranteed to work down as low as minus 20.....and it was a lot, lot cheaper than GSHP.....solar thermal would be a waste of money IMO. Ducted air conditioning systems are very difficult to fit in a house unless the air on and air off ducts are the correct size for the airflow, the ducting needs to be kept short and must be well insulated (avoid Flexible Duct over 2 metres).There are three types of people in this world...those that can count ...and those that can't!
* The Bitterness of Low Quality is Long Remembered after the Sweetness of Low Price is Forgotten!0 -
Sorry, A2WSHP?0
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Air to Water air source heat pump....There are three types of people in this world...those that can count ...and those that can't!
* The Bitterness of Low Quality is Long Remembered after the Sweetness of Low Price is Forgotten!0 -
Hi there. I have been investigating A2WSHP recently but have been unable to satisfy myself that its a feasible alternative. Can you confirm which unit you are using?My A2WSHP works very very well in minus 10 degrees..... is guaranteed to work down as low as minus 20.....and it was a lot, lot cheaper than GSHP.....solar thermal would be a waste of money IMO. Ducted air conditioning systems are very difficult to fit in a house unless the air on and air off ducts are the correct size for the airflow, the ducting needs to be kept short and must be well insulated (avoid Flexible Duct over 2 metres).
What sort of outlay was necessary and most importantly, how big are the ongoing costs? Are you using night rate electricity and underfloor heating?0 -
Hi there. I have been investigating A2WSHP recently but have been unable to satisfy myself that its a feasible alternative. Can you confirm which unit you are using?
What sort of outlay was necessary and most importantly, how big are the ongoing costs? Are you using night rate electricity and underfloor heating?
Welcome to the forum.
There are hundreds of posts on ASHPs in the LPG and Heating section of this site.
A couple of people have the Mitsubishi Ecodan system.0 -
Oops, didn't realise there was a Heating forum.
Maybe a moderator will move this thread?
So, there are air-conditioning heat pumps that can work in reverse as heaters, but not in low ambient temperatures, and then there are heating only heat pumps that use a refrigerant with a boiling point below minus 20 degrees. Technology really is beyond the ken of mortal man these days.
Ecodan seems to be just what I need for the first floor, which will have wooden floor boards, which would warp if the underfloor heating is too hot. Since the Ecodan flow temperature is lower than GCH, and adjustable separately from the hot water, it's very promising.
I don't like the idea of underfloor heating for the ground floor, so might have to keep it gas/radiator. I do wonder if it's possible to put in fan/coils mounted in the ceiling, using the Ecodan circuit. The fans would be switched on/off by a room thermostat. Probably too noisy, though.0 -
Oops, didn't realise there was a Heating forum.
Maybe a moderator will move this thread?
So, there are air-conditioning heat pumps that can work in reverse as heaters, but not in low ambient temperatures, and then there are heating only heat pumps that use a refrigerant with a boiling point below minus 20 degrees. Technology really is beyond the ken of mortal man these days.
Ecodan seems to be just what I need for the first floor, which will have wooden floor boards, which would warp if the underfloor heating is too hot. Since the Ecodan flow temperature is lower than GCH, and adjustable separately from the hot water, it's very promising.
I don't like the idea of underfloor heating for the ground floor, so might have to keep it gas/radiator. I do wonder if it's possible to put in fan/coils mounted in the ceiling, using the Ecodan circuit. The fans would be switched on/off by a room thermostat. Probably too noisy, though.
IMO to have both gas CH and an Ecodan ASHP is impractical and overkill!
If you have gas, I would not contemplate ASHP's - that might change in the future.0 -
IMO to have both gas CH and an Ecodan ASHP is impractical and overkill!
If you have gas, I would not contemplate ASHP's - that might change in the future.
The house is undergoing major renovation, so have to get all the pipes and cables (and possibly air ducts) sorted. I think underfloor heating is the way to go for 1st floor. If I cannot drive it using a GCH boiler, because the radiator circuit is too hot, then an EcoDan might be an intermediate solution, until Ground Source borehole prices come down.
Maybe a low temperature thermostore for the underfloor circuit? Could heat it with a solar panel, supplemented by the GCH.
I should just emigrate to somewhere warm. Build a shack, fish all day. Land on Tivalu must be cheap these days.0 -
Hai,
Just want to tell that ingramswaterandair provides full time customer help in any questions related to Geothermal Heat Pumps !
Thanks0
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