Ground Source Heat Pumps

lovesgshp

Fly100 wrote: »

Read 17 pages with interest, im just above to stat the trip into GSHP. So I have a couple of questions...
Its going to be a new build in Lincolnshire. Insulation will be regs plus 20% id suggest more if its economical.
Ive spoke to a couple of installers so far and they can see a big job coming there way so its all yes yes yes at the min.
Questions...
GSHP powered by solar panels (4 or 6kw using them over 12 months) So that should even out the highs and lows ???
Yes, that is okay. Make sure you allow enough for the pump specs, re power size.

Solar tubes to boost DHW in summer leaving the GSHP doing minimal work ??
Not really required. Normal operating times for a GSHP on water heating in summer are about 1hr or less depending on the DHW tank size, plus timer settings. Suggest you forget that expense.

Buffer tank connected to a log stove (boiler type) to boost in the winter months ( I get free wood but lifestyle rules it out as full time solution)
You will probably need a heatstore type system for the different inputs. You are going to overcomplicate the system.

My aim is to invest in renewables to get my heating for free and possibly provide my electricity for free also. I understand the peaks and troffs of the seasons, but aim to use my electricity account as a bank. putting in during the summer and withdrawing in the winter.


Thoughts??


Thank you in advance.




FLY

Welcome to the forum.
You do not say if it is underfloor or radiator heating. If UF then I would honestly not bother with the heatstore.
Forget the solar water heating, you will not save anything in reality. DHW production should be circa 20% of the pump operation over a year.
HTH

captainhindsight_2

thechippy wrote: »

There is a major factor to consider with gshp's....

They are ok at first, as the surrounding temp is more stable in the borehole or ground loop than an ashp.

However, over a period of years, the temp around the borehole / loop gradually declines and the environment is unable to replace the latent heat at the same rate as it's extracted. This means that the efficiency of the system will gradually decline. This can and DOES happen, but it can be several years before it's noticed.

Hi Chippy, i have had a GSHP fitted i have had trenches dug but not had the pipework fitted in loops and have had one continuous run of pipework which i insisted on over a larger area (i own a farm so space was not a problem, it did obviously take more time because more trenches were needed). I was aware of what you had said above but I was wondering what you or other people think of what I have had done and whether you think it is an appropriate solution to the problem you mentioned if you have the space

lovesgshp

Perfectly okay to have straight runs of the underground piping. Spacing between should be about 30 cms for flow and return.
We do not use the loop type system here.

beardymarrow

Hi guys,
We've just moved into a house that has an IVT Greenline E GSHP. Our electricity meter is going crazy, and we're consuming on average 80kWh per day.

Most of the day we are running at approx 4kW (for the whole house) with a few dips for 30Mins or so down to about 500W, and some higher peaks (when we've got the oven on or whatnot) up to 8kW. During one of the 4kW periods I went to the GSHP and switched it off and usage dropped to 500W, and I've done this a couple of times, so I know it's that causing the high usage.

It basically seems to be producing hotwater far too often. In fact every time I've been to it, it says it's in "HOTWATER MODE", but weirdly says "Set Temp 51, Present Temp 56.1" (or similar, but always Present Temp is higher than Set Temp).

I've changed the DHW to switch off at night now to try to help, but what else can I do. The readings on it are :-

GT1 On 16.4, Now 29.4
GT2 15.5
GT3 Tgt 51 Now 55
GT5 Tgt 10.6 Now 19.7
GT6 105
GT8 57
GT9 50.7
GT10 0.7
GT11 -2.4

Heat Pump Hours 12992 (up from 12918 5 days ago, so 14Hrs/day)
66% DHW, 34% RAD
Add Heat Hours 588 (not increased in 5 days)

Hope someone can help, as I wasn't expecting £350 per month leccy bills :-(

Cheers

lovesgshp

Hi beardymarrow and welcome.
Firstly check the DHW tank. On the top there should be a small brass valve, with a knurled wheel. This is a air bleed, so open it slowly and make sure that only water is expelled.
Next, you need to check the hot water peak and how many days it is set for, in the K2 menu. 66% for DHW is far too high.
GT5: Room temp, set @ 10.6? What influence is that set at?
GT6 Compressor temp is far too high. You need to take the front cover off the pump and check the sight glass in the bottom right when the pump is running. Make sure there are no air bubbles showing after say 5 mins of operating.
Finally for the moment, rads or UFH and what is the level of the heat. (0 to 10 )?

beardymarrow

lovesgshp wrote: »

Hi beardymarrow and welcome.
Firstly check the DHW tank. On the top there should be a small brass valve, with a knurled wheel. This is a air bleed, so open it slowly and make sure that only water is expelled.
Next, you need to check the hot water peak and how many days it is set for, in the K2 menu. 66% for DHW is far too high.
GT5: Room temp, set @ 10.6? What influence is that set at?
GT6 Compressor temp is far too high. You need to take the front cover off the pump and check the sight glass in the bottom right when the pump is running. Make sure there are no air bubbles showing after say 5 mins of operating.
Finally for the moment, rads or UFH and what is the level of the heat. (0 to 10 )?

Hi lovesgshp,
Thanks for such a speedy reply.

There was quite a lot of air that got bled off the DHW tank. It's now only bleeding water though.

Hot water peak is set to Su (options are mo, tu, we, th, fr, sa, su, Daily and Inactive), so I guess Su means it does the pasteurisation once a week on a Sunday?

Room Temp Sensor Influence is set to 0 (No influence at all?).

The sight glass was very cloudy when it started, but after less than 1 min ran completely clear. Annoyingly I had to change the Summer Disconnection Temp to get it to kick in, as for once it wasn't running when I went to it. Sod's law :-)

We have Rads and UFH. UFH in about half of the ground floor, rads for the rest of the ground floor and all of the 1st and 2nd floors.

Temp incr/decr (Menu 1.1) is set to 3.0. Hope this is what you meant me to check.

I think I might be jumping to the conclusion that it's the DHW, as it's saying HOTWATER MODE, but I've realised that might not mean DHW, but rather referring to production of heating hot water as well?

Cheers

Beardy

lovesgshp

beardymarrow wrote: »

Hi lovesgshp,
Thanks for such a speedy reply.

There was quite a lot of air that got bled off the DHW tank. It's now only bleeding water though.
That should improve the DHW operating times

Hot water peak is set to Su (options are mo, tu, we, th, fr, sa, su, Daily and Inactive), so I guess Su means it does the pasteurisation once a week on a Sunday?
Hot water peak should show days i.e 1 to 30. What menu number are you looking at?

Room Temp Sensor Influence is set to 0 (No influence at all?).
Yes, that is no influence ........ set to 5 to start off with, and set room temp to 19C to start with at the moment.

The sight glass was very cloudy when it started, but after less than 1 min ran completely clear. Annoyingly I had to change the Summer Disconnection Temp to get it to kick in, as for once it wasn't running when I went to it. Sod's law :-)
What temp is summer disconnect set at?

We have Rads and UFH. UFH in about half of the ground floor, rads for the rest of the ground floor and all of the 1st and 2nd floors.

Temp incr/decr (Menu 1.1) is set to 3.0. Hope this is what you meant me to check.
Far too low for a rad/UHF system. Change to 4.5 initially and we can work on from there. Presume there is a buffer tank and if so let me know the "heat curve/break temps" down to 0C from +20C. They are in 5C divisions.

I think I might be jumping to the conclusion that it's the DHW, as it's saying HOTWATER MODE, but I've realised that might not mean DHW, but rather referring to production of heating hot water as well?
Hot water mode is DHW only.

Cheers

Beardy

Let me know how you get on with those adjustments and we can check further from there.

beardymarrow

Cheers for that.

I'm looking at Menu 2.2 (Interval for hot water peak). The options are Mo, Tu, We, Th, Fr, Sa, Su, Daily and Inactive. It doesn't match the description of that menu item in the manual, as that says it's an interval (like you say), as opposed to what day you want it doing on (or daily, or off).

Summer Disconnect is set to 11oC.

I'll change the Room Temp to 19, Influence to 5 and Temp Incr/Decr to 4.5, but just one quick question before I do, as actually we are happy with the temperature of the house, in fact if anything it is too hot sometimes, especially in the UHF parts of the house (although those rooms do have a lot of glass that gets the direct sun, so we've put it down to that). It's not too hot in the rad areas (including the one that has the temp sensor in it) as we have most of those switched off at the thermostats on them (except the ones that don't have thermostats of course, which is quite a few of them). That looks like it will make it warmer in the house than before?

I don't know if there is a buffer tank. I can't see one if there is one, and I don't get the mix valve incr/decr menu, or a value for GT4, so I'm assuming not, but I must admit I barely understood our gas fired boiler at the old house, and this is a different ball-game altogether. Determined to learn though!

Anyhoo, the Heat Curve Adjustment figures from 1.3 are :-
20 = 14.9
15 = 19.4
10 = 21.8
5 = 24.2
0 = 18
-5 = 19
-10 = 25
-15 = 24.9
-20 = 25
-25 = 34.4
-30 = 41
-35 = 43.4
but I don't think that's what you are after?

Thank you for your help so far.

Beardy

lovesgshp

beardymarrow wrote: »

Cheers for that.

I'm looking at Menu 2.2 (Interval for hot water peak). The options are Mo, Tu, We, Th, Fr, Sa, Su, Daily and Inactive. It doesn't match the description of that menu item in the manual, as that says it's an interval (like you say), as opposed to what day you want it doing on (or daily, or off).
That is throwing me, as should be a period setting and not on a daily basis. What is the software rego number: 600/637?

Summer Disconnect is set to 11oC.
Change to min 16C, default is 18C.

I'll change the Room Temp to 19, Influence to 5 and Temp Incr/Decr to 4.5, but just one quick question before I do, as actually we are happy with the temperature of the house, in fact if anything it is too hot sometimes, especially in the UHF parts of the house (although those rooms do have a lot of glass that gets the direct sun, so we've put it down to that). It's not too hot in the rad areas (including the one that has the temp sensor in it) as we have most of those switched off at the thermostats on them (except the ones that don't have thermostats of course, which is quite a few of them). That looks like it will make it warmer in the house than before?
Room sensor influence should keep it stable, as at present the outside sensor has full control and will alter the heat curve to compensate for lower outside temps.

I don't know if there is a buffer tank. I can't see one if there is one, and I don't get the mix valve incr/decr menu, or a value for GT4, so I'm assuming not, but I must admit I barely understood our gas fired boiler at the old house, and this is a different ball-game altogether. Determined to learn though!
Would have thought there would be a buffer tank in the installation to help the temperature range adjustment between UHF/Rad requirements.

Anyhoo, the Heat Curve Adjustment figures from 1.3 are :-
20 = 14.9
15 = 19.4
10 = 21.8
5 = 24.2
0 = 18
-5 = 19
-10 = 25
-15 = 24.9
-20 = 25
-25 = 34.4
-30 = 41
-35 = 43.4
but I don't think that's what you are after?
It looks like someone has altered the heat curves from 20C , as they should be higher. At 5C you are showing 24.2, but at 0C 18.0. We may need to do a factory reset, otherwise I need to give you the figures to change, if you feel confident enough to change them.

Thank you for your help so far.

Beardy

Looks like someone has made a lot of alterations to the system, but it can all be resolved.

lovesgshp

Just put your basic heat curve adjust break figures into the simulator and these are the base results:
At a level of 3 without the the temp increase/decrease:
20C = 20C
15C = 22.4
10C = 24.8
5C = 27.2
0C = 29.6
-5C = 32.0

At the 4.5 level, the following:

20C = 20
15C = 23.6
10C = 27.2
5C = 30.8
0C = 34.4
-5C = 38
-10C= 41.6

These are the return feed temperatures for the heating system.
Is the room sensor not in a hallway?