Open loop ground source heat pump.

[daftlad]

I guess if I was going to pump back and forth it would make more sense to just drop long loops of pipe down both of them and go closed loop? Like nowty?

Peas

[nowty]

I guess if I was going to pump back and forth it would make more sense to just drop long loops of pipe down both of them and go closed loop? Like nowty?

Peas

Sounds better TBH, the bit in the well's could be copper and the bits in between could be plastic to reduce cost. And the heatpump in the middle, or even two heatpumps, one at each well site.

[Gareth J]

If planning to do as above, do some back of the envelope calculations regarding what replenishment rate you need in order to stop the water freezing at full usage rate. Then, remember that the exchange rate from groundwater to well won't be as much as what it would be if you pumped the water out and let groundwater seep back in. It'll depend on lots of things to do an accurate estimate, (the surface area/s of your well/s being critical) but you might be able to rule it out.

[Oliver90owner]

Going back to the original post - do you really need 15kW? Are the system parts going to located within the building, or elsewhere - the heat dissipated by the component parts might be added to the building or completely lost (if the pumps,etc are located elsewhere)?

That is a lot of energy per day! Insulation and draught sealing might reduce the requirement by a tidy amount at much less cost. A lower ‘base load’ with other forms of back-up heating, for the worst weather conditions, might be a better option.

Also your eggs are not all in one basket, as they say, if you have alternative energy sources.

Our little house, with careful selective heating, does not really need the 12kW capacity of the gas boiler fitted for much of the time - but it probably cycles better than a heat pump system would.

Currently, most of our (meagre) space heating is by means of a gas fire with about 1.8kW input, with a further 3.6kW input available should it be needed.

We don’t heat the whole house for the whole time and use less energy than the average similar property.

[daftlad]

I now have a submersible well pump :-) not plumbed in yet.
The second well is 10m to the water level with 1.8m of water, maybe more depending on how much mud and silt is in the bottom???! It's about 1m diameter so holds about 1400 litres, so for doesn't seem that promising?
Not sure if we need 15 kw? The house will have a very well insulated loft (28 or 30cm of wood wool) but the walls are half metre thick stone ( about half of which will be insulated on the inside) we actually in due course will have a 3 bed house and a second 2 bed with 4 total downstairs rooms.
Both houses will be approximately 161m2 total.
Both living rooms will have wood stoves and won't have underfloor heating so only a bit of background heat from a radiator. And the se for the laundry room, the only other downstairs room will have underfloor heating in screed, the bedrooms and bathrooms will all have wood floors with underfloor heating.
We are like you Oliver but we plan on renting the second house and people on holiday seem to like it hot hot hot!
At least they don't mind lighting the
Feel free to rubbish any or all! Of my design choices???

Peas

[nowty]

daftlad, if you have not noticed, I have started to re-write my water sourced heatpump project which was lost after an earlier website shut down,

https://camelot-forum.co.uk/phpBB3/view ... f=17&t=487

Some of the info in the thread might be of use to you. I note the same company I bought my heatpump from are now selling a slightly more powerful one on ebay and through their own website. Apart from me buying a product from them I have no other connection with the company.

https://www.ebay.co.uk/itm/114431455503 ... 0290.m3507

[wookey]

Nowty's quality post reminds me why this is such a fine collection of people :-)
I need to get a heatpump too to get rid of the gas so after a very long pause away from this forum will be back. My neighbour has made his own 3kW GSHP for about £1600 so I may well just copy his design as we really don't need very much heat after major insulation+airtightness work.

[Stinsy]

It is very difficult to find small heat pumps. And the ones on the market are astonishingly expensive for what is essentially a very simple device.

You can buy a fridge for £150. You can get an air-to-air heat pump installed for £1500. So why are air-to-water or water-to-water heat pumps £10k?

[Paul_F]

One note on open loop .vs. closed loop: with an open loop system you pump the water all the way up from the well, and then it falls down under gravity again - you can't recover the energy from it dropping back down since the open end is at atmospheric pressure and this converts the energy to kinetic energy and then heat (turbulence) when it re-joins the water body. With a closed-loop system it's in one continuous piece of pipe you don't have this effect. The upshot is that unless you aren't pumping the water up more than a very short distance (for example a system on a boat), the COP impact of an open loop system is pretty calamitous.

[Gareth J]

One note on open loop .vs. closed loop: with an open loop system you pump the water all the way up from the well, and then it falls down under gravity again - you can't recover the energy from it dropping back down since the open end is at atmospheric pressure and this converts the energy to kinetic energy and then heat (turbulence) when it re-joins the water body. With a closed-loop system it's in one continuous piece of pipe you don't have this effect. The upshot is that unless you aren't pumping the water up more than a very short distance (for example a system on a boat), the COP impact of an open loop system is pretty calamitous.

Devils advocate;
If the returned water were splashing about and loosing energy by creating heat via turbulence, surely the heat pump would have a crack at hoovering up some of that energy next time around? (I have no idea if in practice this would be anything more than negligible!)

Alternatively, if the outlet of the return were always submerged, it'd be closer to a closed loop system in terms of circulation energy requirements.

I have considered an open loop system here, fortunately, the bottom of the river fed sump is above where the HP would be housed and water could be returned to the stream lower again, with gravity doing a lot of the heavy lifting.