Heat Pumps

[Infidel]

Has anyone had any expierience of them? and in particular the most common form of heat distribution around a house ie rads, warm air or underfloor.
Just been thinking about it for a possible new build with no gas supply except lpg or oil.
Tia.

 

[Norcon]

Youd be better off converting the amount in £ sterling your budget stretches too into Zimbabwe dollars and burning that to keep warm and provide you're hot water requirements.

 

[doitall]

Low temperature is best, e.g. underfloor.

Couple it up with a thermal store you can add solar as well for the best hot water in the summer.

Ground source heat pumps or bore holes are best, but the later adds considerably to the install.

 

[DeltaT]

Low temperature is best, e.g. underfloor.

Couple it up with a thermal store you can add solar as well for the best hot water in the summer.

Ground source heat pumps or bore holes are best, but the later adds considerably to the install.

With the greatest of respect 'doitall', a thermal store is far from the best unit to attach a solar system too. Given that you would require a high primary water temperature for a thermal store or heat bank & a narrow tall cylinder is always the best option with solar - but not readily available in that type of unit.

A Geothermal HP would be best alongside a buffer tank & UFH. You would also require something like an electric/LPG/oil boiler to boost your hot water. What with the 'feed-in tariff' and a well insulated home, you'd be quids in.

I hope that's of some help & i'm so pleased to see some new build coming along, we need it!!!

 

[DrRob]

Seen them working and heating a pool with no problems throughout winter.

Am in the process of having one installed right now.

 

[DeltaT]

It would be interesting to see if any of the 'Greenwash Ex-used car salesmen' selling these units have revised the COP, after last Winter!!

The ASHP are useless at temperatures of >0 C, in fact they're cr.p at even >8 C!!

 

[mysteryman]

I agree with all of the above.

The best heat emitters for underfloor are underfloor in concrete screed. This gives you the thermal mass you need to prevent short-cycling. You should limit the heat pump output to 60% of the theoretical heat load of the house for the same reason. In the very rare case that you need more heat, a woodburner can be used, or supplementary electric heating. If it is underfloor in all suspended floors, then you will need a buffer vessel to even out demand.

As stated air source heat pumps are ineffective below freezing point, and ground source performance drops off throughout winter. Boreholes are best if you must.

You need ideally a twin coil solar cyl with the coils in series, both connected to the heat pump, because of the low delta T between the heat pump flow temp and dhw temp. If you want solar as well, either that or the heat pump will need a plate heat exchanger set.

There are no circumstances in which I would install a heat pump in my own property.

 

[Norcon]

There are no circumstances in which I would install a heat pump in my own property.

Hot sticky sweltering summer and a domestic air to air split unit can come in handy.

 

[Boilerman2]

If you really want a Heat pump, go for a decent one such as Daikin Altherma, linked to a thermal store, with solar thermal and a WOODBURNER, when it's cold you will be gratefull for the input that the boiler on the woodburner would add to the thermal store if new build, Underfloor would probably be best in terms of efficiency and effectiveness

 

[ajstoneservices]

You need ideally a twin coil solar cyl with the coils in series, both connected to the heat pump, because of the low delta T between the heat pump flow temp and dhw temp. If you want solar as well, either that or the heat pump will need a plate heat exchanger set.

Kingspan, Gledhill, and Telford make a range of heat pump ready cylinders that have large surface area coils 3m2 plus ( no need to link in series) along with a solar coil. so no need to add an external heat exchanger.

You could also get a suitable cylinder made by Newark, Mcdonalds, err, I could supply one.

I cant think why anyone would claim thermal stores won't work with solar.

 

[DeltaT]

You need ideally a twin coil solar cyl with the coils in series, both connected to the heat pump, because of the low delta T between the heat pump flow temp and dhw temp. If you want solar as well, either that or the heat pump will need a plate heat exchanger set.

Kingspan, Gledhill, and Telford make a range of heat pump ready cylinders that have large surface area coils 3m2 plus ( no need to link in series) along with a solar coil. so no need to add an external heat exchanger.

You could also get a suitable cylinder made by Newark, Mcdonalds, err, I could supply one.

I cant think why anyone would claim thermal stores won't work with solar.

As I stated above, any thermal store/heatbank requires a high primary water temperature(75-80*C) & given that a solar system will only heat up any cylinder very slowly. It is far better at heating a standard tall slim type cylinder providing hot water directly at 50-60*C.

If you fail to understand this, please ask me & i'll 'dumb it down' for you.

You're not BigBurner/DrDrivel/WaterSystems are you??

 

[DeltaT]

If you really want a Heat pump, go for a decent one such as Daikin Altherma, linked to a thermal store, with solar thermal and a WOODBURNER, when it's cold you will be gratefull for the input that the boiler on the woodburner would add to the thermal store if new build, Underfloor would probably be best in terms of efficiency and effectiveness

Forgive me if I'm wrong Boilerman', but did Daikin not have some problems with their gear, re-calling some HPs??

Good call about having a wee woodstove, but thermal stores/heatbanks are rubbish with HPs or solar.

 

[Infidel]

Thanks for all the pro's and cons, as I'm a little bit of a fiddler with already used technology I was proposing a bio mass pit, straw pile, or both.
Failing that put a bloody jumper on and light a candle.

 

[DeltaT]

Thanks for all the pro's and cons, as I'm a little bit of a fiddler with already used technology I was proposing a bio mass pit, straw pile, or both.
Failing that put a bloody jumper on and light a candle.

Why not ask around your local area, see what of the above fuels are available? None of the 'Greenwash' heating products are cheap!! The best thing to do is spend as much as you can on insulating your new home, then get a good heat-loss calc done. Chancer are you'll be able to heat it with no more than a Mouse fart!!

A Greenwash heating appliance are for Xmas, insulation is for life!!

 

[Infidel]

Why not ask around your local area, see what of the above fuels are available? None of the 'Greenwash' heating products are cheap!! The best thing to do is spend as much as you can on insulating your new home, then get a good heat-loss calc done. Chancer are you'll be able to heat it with no more than a Mouse fart!!

A Greenwash heating appliance are for Xmas, insulation is for life!!

Insulation will of course be heavy but I'd like to design it on a multi level approach, so a heat pump with multiple supplies for the winter, and an A/C enviroment for summer any heat could be used for hot water.
As for solar voltaic cells not worth the effort so far.