Geothermal Brine Values?

jasgrif11

Hi,

Can you please post some of your Brine in/out temperatures.

I recently got a Nibe heat pump fitted and I'm seeing temperatures in of 2.5deg and out at 0.5deg these seem rather low, or is just cos of the last 2 weeks of cold weather.

I should mention that I'm using 2 X vertical bore holes 300ft deep.

Thanks
J

2 stroke

Sorry I can't help, but I am interested.
How long was system running when you took these readings. What readings do you get when system is restarted after 24 hours.

jasgrif11

The system has been running for 4 weeks now. I haven't moved into the house yet. For the first 10 days it was on a drying out cycle and since then its controlled from the outside stat. Temperature readings are an average 28 degrees, sometimes reaching 33 on extremely cold days.

I will check the Brine values again today, but Id like to know what other peoples readings are.

Qwerty?

I've a NIBE HP aswell, and just checked my Brine. Its reading In 5.1, Out 4.6. But I have the horizontal loop.

But it's not running at the moment, so these reading are not accurate, as they are measured at the heatpump, not outside. Once the HP starts, the real brine temp will be a little less.

When it's running there should be a 3/4 degree difference between the two.

Q.

twenty8

The previous poster is correct. It is important that there is a 3 -5 degree difference between the 2 values. It doesn't make too much difference what the actual temp of the brine is. This varies quite considerable depending on how active the pump is. If the pump is working hard then the temp will be low. If the house does not need much heat then the temp of the brine will be raised.

Just curious - what temp have you set for the flow? Mine is currently around 28.

Qwerty?

Coefficient dial is set at -1, which at the current outdoor temp of 6°C is giving a flow of 29°C(32°C). I forget what the brackets mean, I think it means the flow at the moment is 29, with a max flow of 32 ???

mr.wiggle

Hi Guys,
I have the same system as yourselves, nibe fighter with UFH.
Here is the sum of my knowledge.
When we moved in the curve-coefficcient was set at 6 and the offset(dial) was at 0. The house got progessively hotter, causing pools and pools of condensation on windows and the front door.(moved in just before xmas, btw I had to switch it offit was ridiculous. One of the guys from Ashgrove came out, explained a few things to me, we set the cur-coef to 5 and let offset to 0.
Still to hot, and still condensation. Ashgrove came out again, and noticed that the stat upstairs was not turning off the motorised valve. Got that sorted and away we went again. Still to warm in the house, so the boss came out,(very nice guy btw), and spent some time going thru the set up,adjusting room flows, explaining it to me, I kept him there until I was happy with it 100%.
It is now at CC-5, offset curve -1 ( although -2 was good for me, she who must be obeyed is cold blooded so -1 it is !)
The brine values vary on the temp outside, but I have noticed it can be 12'c in , on a warm day when the heat pump is off. On a cold night , (0' to 6'), it will be anywhere from 6deg to 4 deg, when the pump is on, with a return of 4 degrees less.
We know just turn on the heat upstairs approx 3 hours before the kids go to bed, and turn it off again whatever time we head up.
I must say how happy I am with it, 24/7 heat and hw, and our first few bills are reasonable.
I'm happy enough with ashgrove, i'd go as far as recommendng them, but the speel of using night rate electricity has me pissed off.
I could go on... pm me for more rants ! hehe
Later..W.

Qwerty?

Glad it's running well now for you. It does take a few months to get the settings right, but after that, you don't have to do anything with it.

mr.wiggle wrote: »

The brine values vary on the temp outside, but I have noticed it can be 12'c in , on a warm day when the heat pump is off..

Just one thing to note here... when the heat pump is off, the reading you are getting is not the soil temp, it's the temp of the brine in the pipes in your house, so naturally the temp of these will be raised by the temp of the UFH room, and the screed.

Whats the story with the Speel of using night rate?

twenty8

Wiggle - I would be careful about turning on and off the heating. The idea of the system is that you don't touch it most of the time. By turning it on and off in different rooms you are losing the benefit of it. Pick a temp that you like and leave it at that.

Just a suggestion.

Qwerty?

twenty8 wrote: »

Wiggle - I would be careful about turning on and off the heating. The idea of the system is that you don't touch it most of the time. By turning it on and off in different rooms you are losing the benefit of it. Pick a temp that you like and leave it at that.

Just a suggestion.

+1 on that. We don't adjust ours at all really. We let the electronics take care of all that.

jasgrif11

ok looks like I had a small air lock and my brine failues now seem fine. My Curve Coef is +4.

mr.wiggle

Qwerty? wrote: »

Whats the story with the Speel of using night rate?

Hi Q,
Well you had to get me started on night rate
Ok here goes. I may rant but i will get to the point.

There are two schools of thought now. When i thought there was only one.
1. Older heat pumps use timers to switch on during the cheaper hours(00.00 - 07.00), heating the slab cheaply,and warming the house for the morning/afternoon hours.
2. Newer pumps, which are on 24/7, use a Temperature Set back Time setting, to increase the temperature of flow during the cheaper hours.( this is manually programmed in by the user, where the times and temp increase can be set).

My issue with NRE, and nibe pumps which are on 24/7, is that the Degree minutes are not built up to a sufficiently positive value to benefit from using the Temp. Set back setting. I have come down in the morning to see my degree minutes several hundred in the minus !!! Yes, minus !!
I explained my findings to ashgrove, along with questions of why NRE is recommended, and received no answers !
In fact they turned off the Set back Time setting as it was proving of no benefit to me .
For those of you who don't know about Degree minutes, the heat pump switches on at -60ish degree minutes, and using a combination of factors ( time on/temp's and curves), it switches off when it gets to a positive value.
The most positive i've seen is +50. Then, again depending on several factors, these degree minutes, trickle back down to -60ish, and it starts all over again).

All I can presume is NRE was/is a huge benefit if you have a pump which is turned off/on using timers, but for 24/7 pumps, I just don't know.

Excuse me if I have confused anyone, but I did warn you all in an earlier post !:)

Please don't have a go at me , if anyone thinks they can better explain it, then please do.
Plus this is not a comment on Ashgrove, as like I have stated previously, I am happy with them.

Later., W.:cool:

mr.wiggle

twenty8 wrote: »

Wiggle - I would be careful about turning on and off the heating. The idea of the system is that you don't touch it most of the time. By turning it on and off in different rooms you are losing the benefit of it. Pick a temp that you like and leave it at that.

Just a suggestion.

Hi t8, the only room i turn it off on , is the sun room, as it's not really used in the winter months and the heat loss is the greatest in there due to all the window's. I do give it a blast a week a month just to keep any damp at bay.

W.

Nordic

jasgrif11 wrote: »

Hi,

Can you please post some of your Brine in/out temperatures.

I recently got a Nibe heat pump fitted and I'm seeing temperatures in of 2.5deg and out at 0.5deg these seem rather low, or is just cos of the last 2 weeks of cold weather.

I should mention that I'm using 2 X vertical bore holes 300ft deep.

Thanks
J

Your heat pump should have 150m of loop pipe per ton of compressor capacity. What is the compressor in your heat pump and I can tell you what length of loop you should have?

If you have read any of the posts I have put up here over the last couple of years, you are suffering from exactly what I was talking about.

If you talk off the heat pump cover and read the label on the compressor and e-mail me at info@nordic-geothermal.com I'll be able to give you the exact answer to your question.
Please also give me the compressor manufacurer i.e. Copeland?

Also...what size is your house?

Regards
Niall