Ground source heat

[Farmer_Joe]

mine seems good, longer its been in and pipe settled in ground fully for best heat exchange the better it does,

think mines an 8kw with 300m should have put more loop in really will get temps tomoz they brine temps can drop quite low but it still works fine

 

[24/7 farming]

Mine just starting to have to work a bit now, just cranked up the circulating temp a bit few days ago as it wasn't hitting temps, but is building up nicely nw, allowed to run 8 hours a day on night rate at the min, not running for all of it yet tho.
12kw (max) pump running over 600m.
Massive difference for us tho as we just moved in about this time last yr and were heating a cold house, had it nearly running round the clock!

 

[Mur Huwcun]

We moved in this time lads year aswell so were heating a cold and dampish house. Big mistake! Plasterboard joints cracking, skirting boards shrinking, door casings becoming loose!!

Anyhow we were heating the whole house last winter but have a woodburner in lounge this year but dont seem to get the benefit from the logburner in any reduction in use for the HP.

Yes the temps can drop significantly and still work but I think the COP reduces dramatically. Worst last winter with the beast from the east wind was just under minus for incoming and going out close to minus 5!! Had two days where ice was forming on the manifold! I cheated and ran the immersion for a few hours to reduce the loading on the system and settle the brine temp a bit.

This was the manifold . Was still working but not what I consider ideal!! Half regret now that I did not insist on putting a third loop in, they all told me it would be waste of money as we would need a bigger pump which would consume more electricity to run. In hindsight the third loop could of been turned off to be used half way through winter maybe!!

 

[RushesToo]

Dry / dried ground will reduce the efficiency - it hasn't got contact with anything to suck the heat out. Here in parched [and often sandy] Essex the soil is only just getting wet at depth.

 

[Mur Huwcun]

Dry / dried ground will reduce the efficiency - it hasn't got contact with anything to suck the heat out. Here in parched [and often sandy] Essex the soil is only just getting wet at depth.

We were on wet clay, sand and gravelly ground with water running in the trenches which is hopefully ideal.

 

[A1an]

We have 3 of these systems on three newbuilds and they all work well as long as you haven't skimped on insulation.

Aint that the truth.

Ive just bought some thermal imaging gear and the heat loss on some properties is quite scary. My modern extension loses next to nothing through its roof.

My kennels have some ACO drain along the front of them that drops in to a drain, I can see the heat come out the drain, the drain is 2ft deep.

 

[akaPABLO01]

We moved in this time lads year aswell so were heating a cold and dampish house. Big mistake! Plasterboard joints cracking, skirting boards shrinking, door casings becoming loose!!

Anyhow we were heating the whole house last winter but have a woodburner in lounge this year but dont seem to get the benefit from the logburner in any reduction in use for the HP.

Yes the temps can drop significantly and still work but I think the COP reduces dramatically. Worst last winter with the beast from the east wind was just under minus for incoming and going out close to minus 5!! Had two days where ice was forming on the manifold! I cheated and ran the immersion for a few hours to reduce the loading on the system and settle the brine temp a bit.

This was the manifold . Was still working but not what I consider ideal!! Half regret now that I did not insist on putting a third loop in, they all told me it would be waste of money as we would need a bigger pump which would consume more electricity to run. In hindsight the third loop could of been turned off to be used half way through winter maybe!!

View attachment 742904

How long are the slinkies, how many bedrooms, lastly what was deemed the W/m² absorption?

 

[Mur Huwcun]

How long are the slinkies, how many bedrooms, lastly what was deemed the W/m² absorption?

2 x 100m long 5 foot deep and 5 foot wide trenches. 1 sizeable bedroom and three small bedrooms so theoretically 3 bedrooms. Would have to check the reports for absorption values

 

[akaPABLO01]

2 x 100m long 5 foot deep and 5 foot wide trenches. 1 sizeable bedroom and three small bedrooms so theoretically 3 bedrooms. Would have to check the reports for absorption values

So about 1200m of pipe not including headers, also, you mentioned your soil was “wet clay, sand(gravely) did you mean clay/silt, water saturated, because sandy soils are drought soils?

One last thing, on the paperwork it may say “full load equivalent run hours (fleq)”. What is this hrs?

 

[Mur Huwcun]

So about 1200m of pipe not including headers, also, you mentioned your soil was “wet clay, sand(gravely) did you mean clay/silt, water saturated, because sandy soils are drought soils?

One last thing, on the paperwork it may say “full load equivalent run hours (fleq)”. What is this hrs?

Just over 400m of collector pipe. Field was wet clay to start then some lovely soil then it was sand or gravel similar to all in same as you would use to mix concrete. We kept the sand to one side to bed the pipes as adviced which saved us having to buy some in. Will dig out the quotes etc later on and find the values.

If this makes sense!!

Fleq run hours is 1852

W/m absorbtion 55.9

 

[Farmer_Joe]

i imagine sand and gravel is not ideal,

mine auto selects immersions in extreme circumstances

mines all un drained wet clay, placed purposefully in a wet area, i did 1 300m (single 300m pipe) trench thin so as not to disturb the clay much then packed it with as little sand as possibe then clay back in soil on top. mine should have had more loop but the people selling it to me said it was fine with 300, i would defo put more in if i did it again as it helps with the recovery of the temps.

 

[Mur Huwcun]

Yes I set this one to add heat with immersion when outside temps are below -4. I could of used the field next door which is boggy if I had been told at the time, would of been better but a bit more fiddly.

 

[akaPABLO01]

Just over 400m of collector pipe. Field was wet clay to start then some lovely soil then it was sand or gravel similar to all in same as you would use to mix concrete. We kept the sand to one side to bed the pipes as adviced which saved us having to buy some in. Will dig out the quotes etc later on and find the values.

If this makes sense!!

Fleq run hours is 1852

W/m absorbtion 55.9

W/m doesn’t make much sense, anything from 0-5W/m and clay wet sand should be in the region of 2.4 which to be frank is a very unusual combination. The usual make up with wet clay is loamy or silty which is 1.6 - 2.6 W/m.

What size heat pump are you running and I don’t understand how your ground pipe slinkies are 100m unless you’re running a single length 100m and back to the manifold and don’t have slinkies?

 

[Mur Huwcun]

W/m doesn’t make much sense, anything from 0-5W/m and clay wet sand should be in the region of 2.4 which to be frank is a very unusual combination. The usual make up with wet clay is loamy or silty which is 1.6 - 2.6 W/m.

Then you need the 1.8 value on the docs!!

What size heat pump are you running and I don’t understand how your ground pipe slinkies are 100m unless you’re running a single length 100m and back to the manifold and don’t have slinkies?

8 kw heat pump. Yes, length of pipe not slinkies. Up one side of trench back on other side, about 4-5 foot between them. We had a 4’6” bucket on the digger therefore much easier than trying to dig 300mm wide trenches.

 

[akaPABLO01]

8 kw heat pump. Yes, length of pipe not slinkies. Up one side of trench back on other side, about 4-5 foot between them. We had a 4’6” bucket on the digger therefore much easier than trying to dig 300mm wide trenches.

I see.

One last figure please, what have they measured your homes heat loss value. It’ll be with the fleq and w/m, you’re looking for a figure before kWh.

Also, can you get the exact water and heating figure from your epc.

https://www.epcregister.com/reportSearchAddressTerms.html?redirect=reportSearchAddressByPostcode

I’ll take a look at the figures tomorrow, going watching the footy now.

 

[akaPABLO01]

Completed analysis

 

[akaPABLO01]

@Mur Huwcun
Just got back from a site.
Flow to gshp from slinkies was 6.7°C
Return to slinkies 1.4°C

Internal system
41°C flow
36°C Return


This should be what gshp are achieving current conditions. Heating cylinder 1 hour 4am to 65° every night. System able to reach 60° independent of immersion or secondary water heater.

 

[Mur Huwcun]

@Mur Huwcun
Just got back from a site.
Flow to gshp from slinkies was 6.7°C
Return to slinkies 1.4°C

Internal system
41°C flow
36°C Return


This should be what gshp are achieving current conditions. Heating cylinder 1 hour 4am to 65° every night. System able to reach 60° independent of immersion or secondary water heater.

Loop temps have been higher than that here, only at extreme outside temps does it drop right down though!

Just been out to pump to check now, very similar

Flow from loops 6.6
Return to loop 1.5

Internal
Flow at 44.7
Return at 36.1

We did raise flow temps last winter, maybe I should drop it back down?

 

[akaPABLO01]

Loop temps have been higher than that here, only at extreme outside temps does it drop right down though!

Just been out to pump to check now, very similar

Flow from loops 6.6
Return to loop 1.5

Internal
Flow at 44.7
Return at 36.1

We did raise flow temps last winter, maybe I should drop it back down?

Ideal scop is a 5° difference on both.

 

[Mur Huwcun]

Ideal scop is a 5° difference on both.

Will have to get the manual out to adjust the flow temp than!!