Green Building Forum - Installing a ground source heat pump Sun, 17 May 2026 02:55:03 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217265#Comment_217265 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217265#Comment_217265 Thu, 15 Jan 2015 20:22:57 +0000 djh
I don't agree. . . . .

I got this quote from Wikipedia ...

It is perfectly fine to measure heat output in kWh."

Steamy's point wasn't about the units of measurement. It was, as he said, that electrical energy is different to thermal energy. Try looking at wikipedia:

http://en.wikipedia.org/wiki/Exergy and perhaps http://en.wikipedia.org/wiki/Energy_quality]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217278#Comment_217278 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217278#Comment_217278 Thu, 15 Jan 2015 22:03:58 +0000 Ed Davies Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217284#Comment_217284 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217284#Comment_217284 Thu, 15 Jan 2015 22:36:55 +0000 SteamyTea ).
Posted By: topherSo if your heat pump has a COP of 3.0, you put in 1 Kw and get the equivalent of 3 Kw of heat out. If you have a COP of 4.0, you put 1 Kw in and get equivalent of 4 Kw out, that is 25% better. Tweaking will make your system work better and you will be able to get closer to your theoretical COP.

Or have I got the whole thing wrong?
:wink:]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217287#Comment_217287 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217287#Comment_217287 Thu, 15 Jan 2015 22:49:17 +0000 Ed Davies Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217289#Comment_217289 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217289#Comment_217289 Thu, 15 Jan 2015 22:58:41 +0000 SteamyTea Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217299#Comment_217299 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217299#Comment_217299 Fri, 16 Jan 2015 10:55:41 +0000 topher
I think we are all in agreement. Clearly electrical energy is different to heat energy, but fortunately both can be measured in Kw.

I was just concerned that Boggy might be thinking he can achieve the max possible efficiency by tweaking his heat pump. True, but he might be able to get even more by choosing a heat pump with a greater COP, and getting the heating capacity to match his house.

Now for something completely different. I too have a kWh meter solely measuring heat pump consumption. I have readings noted down. What can I learn from the data?

Regards,...........Topher.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217305#Comment_217305 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217305#Comment_217305 Fri, 16 Jan 2015 11:51:23 +0000 SteamyTea You can plot the meter readings against external temperature if you have enough readings.

Just knowing the total kWh (how big the box of energy is) is of little use in itself.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217307#Comment_217307 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217307#Comment_217307 Fri, 16 Jan 2015 12:39:23 +0000 cjard
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/48327/5045-heat-pump-field-trials.pdf]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217309#Comment_217309 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217309#Comment_217309 Fri, 16 Jan 2015 13:12:41 +0000 topher Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217310#Comment_217310 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217310#Comment_217310 Fri, 16 Jan 2015 13:36:12 +0000 skyewright
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/225825/analysis_data_second_phase_est_heat_pump_field_trials.pdf]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217311#Comment_217311 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217311#Comment_217311 Fri, 16 Jan 2015 13:38:07 +0000 Mikel
Time
boiler out pipe temperature
boiler in pipe temperature
zone 1 temperature
temperature sensor 1
temperature sensor 2
temperature sensor 3
temperature sensor 4
external temperature (I think this comes from the nearest MetOffice station)
heat pump power consumption
heat pump energy consumption
whole home power import
whole home energy import
BINARY_SENSOR_5_METER_POWER
BINARY_SENSOR_5_METER_ENERGY (this is the heat meter reading)
DEVICE_STATUS_1_ON_OFF_SWITCH
heating control zone 1
user setpoint zone 1

In addition, I record the electricity meter reading for the heat pump and whole house twice a day, plus daily PV generation and solar thermal max hot water temperature reached. In addition, I separately record the electricity consumption of the heat pump for hot water generation. I also record the number of times the immersion heater is used and try and estimate how electricity that is using (probably better done from element power and time on).

We have had data from last January (when the electricity meter on the heat pump was installed), last February (when the heat meter installed).

We ran the system using weather compensation up to the end of February and then switched to the trial control system. So I only have most of last February's data for the original system, making comparison with any improvement seen from the trial a little bit tricky.

However, we are seeing SPF (calculated from heat output divided by GSHP electricity consumed) going from 3.2 for the original system to 3.5 for this last month.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217324#Comment_217324 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217324#Comment_217324 Fri, 16 Jan 2015 16:05:11 +0000 topher
I have kWh readings weekly when I am at the house, which is about 50% of the time. When absent, the internal temperature is set to about 13 degrees. I guess I would need some average ambient temperature readings. But from recent posts, I have discovered that I might get a 'heat meter' the would accurately measure the output of the heat pump.

So far I have discovered the Kamstrup 402. Its going to cost quite a bit. So I might not do it.

Any suggestions very welcome.

Regards,............Topher.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217342#Comment_217342 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217342#Comment_217342 Fri, 16 Jan 2015 21:27:41 +0000 SteamyTea All a heat meter does is measure the temperature difference and the velocity of the mass of water flowing. Then multiplies the temp difference by the total mass over the sampling period and multiplies it by the specific heat capacity. That is why DECC are collecting data from MikeL, it checks his HP and the heat meter. If there is a big difference then something is wrong.

You can get some weather data from your nearest Weatherunderground station, best to see what sort it is, Davis Pro's are the best (maybe called a Davis 2 I think). Then you can correlate your energy usage and the external temp. Won't tell you everything, but is useful.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217378#Comment_217378 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217378#Comment_217378 Sat, 17 Jan 2015 16:19:58 +0000 Mikel
It seems to me that you would want the meter to sample at fairly short intervals to get the accuracy.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217429#Comment_217429 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217429#Comment_217429 Sun, 18 Jan 2015 11:37:49 +0000 Ed Davies Posted By: SteamyTea…and multiplies it by the specific heat capacityDoes that get set on the heat meter, somehow? For a district heating system they use more-or-less pure water (doesn't need freeze protection, presumably) so it's well known but for a GSHP with brine or, particularly, for a solar thermal system full of anti-freeze it can be a lot less (half?)]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217435#Comment_217435 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217435#Comment_217435 Sun, 18 Jan 2015 12:06:40 +0000 SteamyTea Don't know much about them. I would hope that it is sorted out somehow.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217446#Comment_217446 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217446#Comment_217446 Sun, 18 Jan 2015 15:15:55 +0000 Mikel
You may be correct with respect to the solar thermal system but it seems to me that the heat meter is on the central heating side, which is water and corrosion inhibitor.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217448#Comment_217448 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217448#Comment_217448 Sun, 18 Jan 2015 15:31:18 +0000 Mikel https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/48043/1386-heat-metering-rhi-gastec-at-cre-ltd.pdf

Note that for solar thermal systems the heat meter is calibrated to take the anti-freeze mixture into account.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217528#Comment_217528 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217528#Comment_217528 Mon, 19 Jan 2015 09:33:29 +0000 Ed Davies Posted By: Mikelbut it seems to me that the heat meter is on the central heating side,Good point, though slightly perverse in that the ground-loop side is the “renewable” bit; it doesn't include the electrical energy. Also, thanks for the link.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217569#Comment_217569 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=217569#Comment_217569 Mon, 19 Jan 2015 14:17:02 +0000 skyewright Posted By: SteamyTeaYou can get some weather data from your nearest Weatherunderground station, best to see what sort it is, Davis Pro's are the best (maybe called a Davis 2 I think).
Davis Vantage Pro 2 (sometimes abbreviated to VP2).

However (at the risk of veering OT) if it's only outdoor temp you are interested in then a much cheaper one will probably only be marginally poorer if you can site it well &/or if you build it's temp sensor a proper housing (think Stevenson screen). It's wind & rain measurements, & a superb console, where the Davis mainly scores over cheaper models, in both precision & longevity. The Davis station can also be extended in various ways if you have a deep enough pocket.

Normal service now resumes...]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=225039#Comment_225039 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=225039#Comment_225039 Fri, 29 May 2015 10:33:20 +0100 topher
In previous reports I have complained about 3 or 4 leaks caused by brass fittings cracking and leaking primary or secondary fluid. I believe it was caused by over-enthuistic tightening, the installer says, as you might expect, that the fittings were defective. The most recent leak in the primary caused the pump to stop because of low flow, but more significantly the liquid damaged the chipboard flooring and the heat pump began to list to one side.

I had the heat pump and inertial cylinder disconnected, the floor repaired with a better quality product, and the heat pump and cylinder re-installed. One extra bit of equipment was added - a heat meter. It has an ultrasonic device to measure flow, and two sensors that measure flow and return temperature. I gave the system a quick test and everything works fine and I can see that it had produced one or two kW of heat output.

In the winter I will note the readings and hopefully be able to measure the COP of the heat pump. I also have a data logger, and hope to use that to give a graphical display of heat over time.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230279#Comment_230279 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230279#Comment_230279 Tue, 06 Oct 2015 08:31:08 +0100 topher
As it was a bit chilly, I put the heat pump on for two days. It consumed 29.7 Kw/h of electricity. It gave 117 Kw/h of heat output as measured with my new heat meter. This gives a COP or efficiency of 3.94. Or I could say, I bought 29.7 Kw/h from EDF. I got 87.3 Kw/h free from the ground.

Seems OK to me. What do you think?]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230280#Comment_230280 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230280#Comment_230280 Tue, 06 Oct 2015 08:52:42 +0100 DarylP how much was the 29.7 from EDF?]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230281#Comment_230281 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230281#Comment_230281 Tue, 06 Oct 2015 09:08:02 +0100 SteamyTea Posted By: topherKw/hIt's kWh

CoP of 4 is good, ground is still warm though. Had it rained recently?]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230283#Comment_230283 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230283#Comment_230283 Tue, 06 Oct 2015 09:20:32 +0100 ringi Posted By: tophersumed 29.7 Kw/h of electricity. It gave 117 Kw/h of heat output as measured with my new heat meter. This gives a COP or efficiency of 3.94. Or I could say, I bought 29.7 Kw/h from EDF. I got 87.3 Kw/h free from the ground.

Seems OK to me. What do you think?

Not much better then using storage heaters, so paying less to EDF for more power.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230288#Comment_230288 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230288#Comment_230288 Tue, 06 Oct 2015 09:38:10 +0100 SteamyTea Posted By: ringiNot much better then using storage heaters, so paying less to EDF for more power.?
My E7 night rate is about 8p/kWh, day rate about 18p/kWh and think the standard rate is around 14 to 15p/kWh.
So only about half price.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230293#Comment_230293 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230293#Comment_230293 Tue, 06 Oct 2015 10:36:13 +0100 ringi
The COP is also likely to be lower when it is colder as the ground would be cooler by then due to the heat being taken out. Ground source heat pumps just seem to give too many issues and not work in a predictable way.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230295#Comment_230295 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230295#Comment_230295 Tue, 06 Oct 2015 10:54:05 +0100 SteamyTea Posted By: ringiWhat if the cost of the ground source heat pump was spent on better insulation etc......Assuming it is a 'slinky' installation rather than a borehole (these are the best), how about if you covered the same area in PV, what would that yield in the winter and what would it cost (putting aside the MCS/FiT nonsense for a while).]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230301#Comment_230301 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230301#Comment_230301 Tue, 06 Oct 2015 11:43:24 +0100 Paul in Montreal Posted By: ringigive too many issues and not work in a predictable way.

This is the 10th season mine has been in use and it has been entirely predictable so I'm not sure what you mean. I have a borehole, though, rather than "slinkies". COP is consistent from year to year and the energy savings have fully covered the cost of the installation (this happened around 3-4 years ago). I have an old house and there are technical limits to how much insulation can be added (really, not much more than 25mm, though air leakage issues have been addressed). My GSHP is water-to-air, as we need cooling in the summer and this kind of system is essentially simpler than water-to-water. The only maintenance required is to replace the air filter on a regular basis.

Paul in Montreal.]]> Installing a ground source heat pump https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230303#Comment_230303 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=230303#Comment_230303 Tue, 06 Oct 2015 12:27:03 +0100 ringi
I expect that a water to air system would be more predictable (provided there a big ducts) as there are a lot less issues with sizing of radiators etc. (Or carpets on UFH)]]>