Experiences with ground source heat pumps?

Hi,

I am considering a ground-source heat pump from Ice Energy... Does anyone have any experiences of these (with the coils under the lawn etc.), and has anyone worked with Ice Energy...

I know these systems are relatively rare in the UK, but they are very common in Sweden and scandinavia generally. We are rural, no gas, so the economics just about add up (the house is very termally efficient...)...

Thanks

mike

Reply to
Mike Deblis
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Mike: Please keep posting your findings here. We live in a similar, probably slightly colder and with a longer winter, climate to the UK. While we have no immediate intention of installing a heat pump, we have a property with potential to install one in a new build within the next few years. So we are very interested. Thanks.

Reply to
Terry

I am also very interested, especially in view of the fuel situation that is rapidly developing. From what I've read the best source is running water, however it does not matter how cold the source is it still has plenty of heat. I know someone is bound to say what about absolute zero! :-)

Reply to
Broadback

Whilst looking for something else, I came across this site

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shows how a system was installed - maybe you could contact the site owner for more info.

Dave

Reply to
logized

Someone mentioned this site a while ago (links directly to their heat pump page)

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Reply to
Colin Wilson

suggest alt.solar.thermal, and somewhat less likely, maybe sci.energy etc. Youve done the maths, the issue with heat pumps is that

  1. as outdoor temp drops, efficiency drops too, so they effectively drop out at some minmum outdoor temp.
  2. Below freezing (at the cold coils) they have to pump heat through ice, and ice insulates. So again, efficiency dies at low temps.

You could provide a significant amount of heat with simple passive solar space heating, and with very attractive figures. And you could possibly use a solar thingy to boost your heat pump efficiency some of the time.

The solar jobs that pay best are homemade flat plates (haeting air not water). Add some reflectors and the performance goes right up.

Regards, NT

Reply to
N. Thornton
[...]

I thought the point with ground source heat pumps (as opposed to the air variety) was that the pipes were buried deep enough to be in that part of the ground which never freezes and which is at a relatively constant temperature year-round. Granted if you take heat out and there's no gain from above there's a slight efficiency drop...

What about the borehole type? Presumably since they go deeper they are both more efficient and able to be installed in a smaller area.

Hwyl!

M.

Reply to
Martin Angove

Boreholes are naturally more efficient, but expensive to get drillers in.

Reply to
IMM

In winter a heat pump may not be able to produce enough hot water at high enough temperatures.

The alternatives are:

  • large solar panels storing water in alarge thermals store using very low temp underfloor heating.
  • Windpower, again using a thermal store and UFH.

You may find that either of the above may come in cheaper than the heat pump.

Reply to
IMM

I have a couple of friends in Sweden with these.

They are effective, but not as the entire source of energy - at least in their climate. THe attraction is partly because of the high cost of electricity.

Taking the heat from the ground does cause the plants to be delayed by

3-4 weeks in the spring compared with the immediate surroundings.

They have to switch the system off for at least a month in the summer, to allow recovery of the ground,

.andy

To email, substitute .nospam with .gl

Reply to
Andy Hall

Did they use a borehole or surface laid?

Reply to
IMM

I believe near the surface, which would account for the effect on the vegetation. I can find out if you're interested.

.andy

To email, substitute .nospam with .gl

Reply to
Andy Hall

Near the surface is pants. Much pants. Using a borehole would mean you don't turn the system off and higher water temps are available.

Reply to
IMM

Uh? Why would higher temperatures be available from bore holes, it's not as if you're getting heat from the earths core.

The bedrooms in our house are cut back into rock, and in summer they're like a fridge on the hottest of super hot days.

I'd have thought pipes a metre below the surface would be able to extract a far higher amount of the heat from the sun as you'd be taking it from the hottest part of the ground, i.e. the part closest to, and directly heated by, the sun.

Reply to
Pet

CO2 heat pumps are coming available that do a good job of generating hot water for DHW.

cheers, Pete.

Reply to
Pete C

In the depths of winter 1 metre down can be near freezing whereas 10 metres down is always around 8 deg C.

Reply to
G&M

But drilling a borehole if you are sitting on hard rock can get seriously expensive on drill heads. In these cases surface is the only option.

Reply to
G&M

Quite. This particular area near Stockholm is most definitely rock, both at the surface or not too far down at all.

.andy

To email, substitute .nospam with .gl

Reply to
Andy Hall

Ah I see. Many thanks G&M

Reply to
Pet

Expensive at the mo'. A full solar south facing roof (easier on a new build), would be very effective. Simply as you have a very large area of solar collector a lot of heat can be gained for the cost of running a pump. Also the cost of converting, or building new, a full integrated solar roof is not as much as you might think. Depending on the work done, etc, about the same, or less than installing a heat pump. A heat pump still needs a heating system, DHW, etc, etc, just like all the others. A wind genny, if you can have one, is very effective. Just have a large thermal store to store all the heat in water, for when . Then use low temperature UFH.

The best of heat pumps at the mo', in running costs, is the equiv to a natural gas condensing boiler. A condensing boiler can be had for £500-700. LPG may even work out cheaper too. As LPG condensing boilers are only slightly more expensive than NG boilers, doing the figures, it may also be more appealing than a heat pump. A condensing boiler is very low capital cost compared to a heat pump. The extra 4-5K spent on a heat pump buys a lot of LPG. If you are off the gas mains, and they may be run in the future, then an LPG boiler that can be converted back to ng is the answer.

Reply to
IMM

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