Heat Pumps - post here.

alfa_aficionado

psham wrote: »

I have a manual for AI1 5008.4 if you want it.. think the menus and error messages are pretty much the same on them.. If you want to pm me your email address I can send it to you.
Never had that error myself ..

Yeah that'd be great...PM sent

SOR2010

So here's my update 1 month on, No difference except I can now tell for certain that my Heat Pump is costing me a small fortune!
In the last month it has used over 1250 units, Contacted the Engineer who came and serviced it and he now thinks its down to the temperature of the pipes in the ground, as the area is very boggy the Brime in is only 1 deg coming into the house but -2 going out??
He's saying due the ground being so wet the temperature never gets up so the HP is running to compensate for this, The problem I have with this is the bills have been crazy for nearly 2 yrs and It wasn't very wet last year but we still had the same problem,
Latest Bill arrived yesterday €536 for 2 months!
Does anyone have any experience with the collection pipes in wet peaty ground? Original Sales Rep told me the ground was ideal....

We have 900m of pipes

sheff the ref

Basically what is happening is that the Delta T (change in temperature) is not occurring, meaning that it is coming in at a lower temperature than it should, going through the system at a lower temperature than it should meaning that it could be taking a few runs through the collector to do the work that should be done in one run through the collector. This is causing the heatpump to overwork and burn electricity. How deep are the pipes below ground level?

SOR2010

sheff the ref wrote: »

Basically what is happening is that the Delta T (change in temperature) is not occurring, meaning that it is coming in at a lower temperature than it should, going through the system at a lower temperature than it should meaning that it could be taking a few runs through the collector to do the work that should be done in one run through the collector. This is causing the heatpump to overwork and burn electricity. How deep are the pipes below ground level?

They are about 1m deep

MicktheMan

SOR2010 wrote: »

House is only 4 yrs old and insulated to a high level, 50mm Warm board on all external walls and pumped beaded insulation in the cavity,

While you say the house is "insulated to a high level", insulation is only half the story when it comes to heat loss. I suspect there may be other issues around heat loss which if addressed may improve the situation somewhat.
Have you had the house pressure tested for air leakage?

Condenser

SOR2010 wrote: »

So here's my update 1 month on, No difference except I can now tell for certain that my Heat Pump is costing me a small fortune!
In the last month it has used over 1250 units, Contacted the Engineer who came and serviced it and he now thinks its down to the temperature of the pipes in the ground, as the area is very boggy the Brime in is only 1 deg coming into the house but -2 going out??
He's saying due the ground being so wet the temperature never gets up so the HP is running to compensate for this, The problem I have with this is the bills have been crazy for nearly 2 yrs and It wasn't very wet last year but we still had the same problem,
Latest Bill arrived yesterday €536 for 2 months!
Does anyone have any experience with the collection pipes in wet peaty ground? Original Sales Rep told me the ground was ideal....

We have 900m of pipes

Your collector should not be installed in a bog. In ground with slow moving water the collector can extract the energy faster than it can be replenished and you can end up freezing the ground.
Your temps aren't too low so I don't think thats the whole story but it is contributing.
How is your system controlled and whats the distribution temp to the ufh.

SOR2010

It's on Auto Winter at present and it's set to about 26-29 deg, living areas are controlled on auto and the bedrooms have stats, the living areas are colder than the bedrooms,

We do have issues with draughts in the kitchen & sitting room which could be the reason these rooms are colder, but I don't think it explains the Cost,

I had it on Spring / Autumn but the whole house was cold then...

planes01

Finally a bit of warmth in the house After 3 months and two massive esb bills. €1000 and this month €620.
Compressor went in our Waterkotte before christmas. Got a new one €2000.
System still wasnt working. Local Installer didnt seem to know to much or care
Saw a post about " Geothermal troublshooters" on here and had them out today.
Diagnosed the problem. Laid out the solution and for a reasonable price.
Wish I had spotted them sooner

hugo29

Hi all

I have a 14kw Heat pump which over the last two months was in use for 579 hours , i calculated this to be approx 278 euro

is this correct

who are these geothermal troubleshooters and where are they based

thanks

Condenser

hugo29 wrote: »

Hi all

I have a 14kw Heat pump which over the last two months was in use for 579 hours , i calculated this to be approx 278 euro

is this correct

who are these geothermal troubleshooters and where are they based

thanks

How did you come to the calculation? Is that all day rate or day and night?
Whats the rated COP of the heat pump. €278 would be quite reasonable for 579hrs of running of a 14kw unit. Correctly sized heat pumps should only run about 2000hrs per year.

planes01

Guy said they were based in dunmore galway but travel.
so relieved to get it sorted.

hugo29

Condenser wrote: »

How did you come to the calculation? Is that all day rate or day and night?
Whats the rated COP of the heat pump. €278 would be quite reasonable for 579hrs of running of a 14kw unit. Correctly sized heat pumps should only run about 2000hrs per year.

i took the 579 hours and times by 4kw and times by 0.12 (average day and night cost) which gave me the above figure but i still have a 750 euro bill so either my calculations are astray or there is something seriously wrong

Condenser

hugo29 wrote: »

i took the 579 hours and times by 4kw and times by 0.12 (average day and night cost) which gave me the above figure but i still have a 750 euro bill so either my calculations are astray or there is something seriously wrong

Is it an air to water? If so the defrosts won't count as running hrs and your COP could be less than you're allowing for as the temps over the last while have been quite cool especially at night or you could be outputting water at a fairly high temp. High winds would affect the defrosting also so it might have been running alot less effectively.

hugo29

Condenser wrote: »

Is it an air to water? If so the defrosts won't count as running hrs and your COP could be less than you're allowing for as the temps over the last while have been quite cool especially at night or you could be outputting water at a fairly high temp. High winds would affect the defrosting also so it might have been running alot less effectively.

No it's a heat pump with vertical boreholes

SOR2010

Does anyone have a Nibe 1140 that would be willing to pass on their settings?
I think mainly the settings in the menu 7.0 under "Service"
from looking at Comp hrs running, Hot Water & Starts there isn't anything jumping out that looks wrong,
But the HP is still drawing a lot of power about €180-200 p/month

HP Troubleshooters didn't live up to their promise!

Abrean

We are hoping to start our new build this year and I'm currently gathering information on ground source heat pumps and we are keen to go down that route. However I've been reading so much here and elsewhere about different brands and am starting to get worried that I'll pick the wrong one! I've read so many horror stories that it would be great to hear more positive stories about different brands of heat pump as people seem to only post online when something goes wrong unfortunately. If anyone has any personal recommendations I'd be glad to hear them as it's going to be a lot of money down the drain if we get this wrong!

ecowise

In terms of the heat pump efficiency the first thing you need to resolve is the ground circuit flow and return temperatures. The figures you quoted (flow of 2 degrees and return of 1 degree) do not seem to make sense. If you have 900m of pipe at 1m depth the return temperature should be the ground temperature at 1m which will be higher than 1 degree C. It seems unlikely but is it possible the connections on the ground circuit are the wrong way round i.e flow and returns are reversed ? My 12 years of experience with a ground source heat pump heating a 250 sq.m house has yielded an annual bill of about 200 euro. I have just discovered an apparent leak in the unit so I think I will need to have it serviced for the first time which is why I was reading this thread!

SOR2010

Ecowise:

I haven't looked at the figures for a while but will check them when I get home today, but they were correct at the time,

I sent an email to the manufacturer yesterday asking if they have any registered Qualified service agents as my experience with so called experts has left me worst off, ie Paying them and still having the problem,
I'm waiting on a reply but I'm not holding my breath...

soundskin

SOR2010 wrote: »

Does anyone have a Nibe 1140 that would be willing to pass on their settings?
I think mainly the settings in the menu 7.0 under "Service"
from looking at Comp hrs running, Hot Water & Starts there isn't anything jumping out that looks wrong,
But the HP is still drawing a lot of power about €180-200 p/month

HP Troubleshooters didn't live up to their promise!

With the service menus open. (go to menu 8.0, press return button 3 times, + button twice, return button once, then toggle small dial left and right to exit)
Hot Water
1.4 start HW 44 (temp in brackets)
1.5 stop HW 50 (temp in brackets)

note if your cylinder it not next to the heat pump then lower these by few degrees but keep 5-6 degrees of a spacing between start and stop

1.7 stop compressor XHW 52

Heating
Make sure you have plenty open circuits, good for efficiency and extend life of your heat pump

2.1 curve set as low as possible

Night Rate (if in use)

Make sure your time is correct especially in winter (summer not important)
7.3.2 +4 degrees
7.3.3-7.3.9 00:00 - 07:00

This means you are adding 4 degrees to the target temperature between mid night and 7am. (remember if you have lots of stats then you are blocking the house from this cheap heating)

Modes
8.2.1 16 degrees
8.2.3 13 degrees

Post your running hours if you can and i'll comment on them. A great insight into running of your heating.

SOR2010

Post your running hours if you can and i'll comment on them. A great insight into running of your heating.[/QUOTE]

Thanks Soundskin:

I've checked all my settings and there the same as yours except for:
1.5 stop HW 52

2.1 Curve was at 5 now changed to 2 to see if it makes a difference (this was at 7 a month ago and I changed it to 5)

7.3.2 +3
7.3.3-7.3.9 03:00-06:00

My running hours I have as well
1.10 - 1272Hr 42min HWR
5.6 - 16898 Starts
5.9 - 10016Hr 03min Comp run time
9.1.3 - 1666Hr 04min Add Heat

Since the 10th Jan the HP has used 3538 Units which works out about 26kw p/day,
Maybe dropping the Curve from 7 to 5 made a difference, as the first few months it was using 60 units p/day...

Any advise is appreciated

ecowise

Did you check your flow and return temperatures on the ground loop? If you are not getting a temperature gain here your heat pump will be less efficient than an electric fire (COP=1) no matter what settings you use. This is because if your return is not warmer than your flow your only source of heat is the work being done by the compressor. To get a good COP you must be gaining heat from the ground (or air for an air source heat pump). A temperature gain of about 6 degrees would be reasonable and will lead to a good COP. Our heat pump used a total of 1668 kWh (units) for the entire 2013/14 heating season. We have solar panels for hot water and this year we used a wood stove instead of the heat pump for much of the spring so our usage was somewhat lower than usual.

SOR2010

Thanks Ecowise

Sorry i forgot to mention Brime in 9.6 Out 8.6

ecowise

Your outflow temperature is way to high at 8.6, it should be close to zero. Does your unit have a sight glass and can you see that the working fluid level is ok?

Condenser

ecowise wrote: »

Your outflow temperature is way to high at 8.6, it should be close to zero. Does your unit have a sight glass and can you see that the working fluid level is ok?

I agree that his flow return temps are too close together but his return should not be close to zero.


There should be 3-4 C optimally between flow and return. You get as much energy from a smaller differential and faster flow as you will from a large diff and slower flow without placing as much pressure on the ground. 1C is too small a difference to allow transfer however.


Ideally he should set his pump back by one speed setting and try to get a 3-4C diff.

soundskin

ecowise wrote: »

Did you check your flow and return temperatures on the ground loop? If you are not getting a temperature gain here your heat pump will be less efficient than an electric fire (COP=1) no matter what settings you use. This is because if your return is not warmer than your flow your only source of heat is the work being done by the compressor. To get a good COP you must be gaining heat from the ground (or air for an air source heat pump). A temperature gain of about 6 degrees would be reasonable and will lead to a good COP. Our heat pump used a total of 1668 kWh (units) for the entire 2013/14 heating season. We have solar panels for hot water and this year we used a wood stove instead of the heat pump for much of the spring so our usage was somewhat lower than usual.

SOR2010 wrote: »

Thanks Ecowise

Sorry i forgot to mention Brime in 9.6 Out 8.6

Those temperatures are more than likely when the compressor isn't running so they should not be noted (stationary fluid). Only when the compressor is running will you see your differential of 3-5ºC between the flow and return (brine in and out). So brine in would be 7ºC and out would be 3ºC.

Be aware that Nibe brine sensors do fail (usually upwards) and read the incorrect temperature.

soundskin

SOR2010 wrote: »

Post your running hours if you can and i'll comment on them. A great insight into running of your heating.

Thanks Soundskin:

I've checked all my settings and there the same as yours except for:
1.5 stop HW 52

2.1 Curve was at 5 now changed to 2 to see if it makes a difference (this was at 7 a month ago and I changed it to 5)

7.3.2 +3
7.3.3-7.3.9 03:00-06:00

My running hours I have as well
1.10 - 1272Hr 42min HWR
5.6 - 16898 Starts
5.9 - 10016Hr 03min Comp run time
9.1.3 - 1666Hr 04min Add Heat

Since the 10th Jan the HP has used 3538 Units which works out about 26kw p/day,
Maybe dropping the Curve from 7 to 5 made a difference, as the first few months it was using 60 units p/day...

Any advise is appreciated[/QUOTE]

Yes going from curve 7 to 5 will make a big difference. Doing down as low as 2 will mean you will be a lot cooler in your house, if you can live that then happy days as it will be a lot cheaper for you. It's hard to give up constant heat when you get used to it.

In relation to your running times:
13% run time for hot water (average is 15%).
2 starts for every hour means you have plenty open circuits which is good.
Assuming your units draws on average 14 amps (hot water cycle and heating) and your average cost is 15c/kWhr (day rate and night rate).
I believe your heat pump has cost you roughly €5,800 since it was installed. or 38,561 kWhrs.

So if your heat pump has only done 13% (€754) of its work on hot water then you can see that when you make savings it's with adjusting down your heating

ecowise

The temperatures to read must be when the pump is actually in heat pump mode. You should check them ideally after it has been running long enough to have achieved a more or less steady state, perhaps about 15 mins (not a scientific estimate!).

In terms of efficiency and ground loop delta T (T return - T flow), this efficiency depends on how low the heat pump can reduce the flow temperate and how high the ground loop can increase it. The latter is determined by the parameters of your ground loop. These parameters include length and geometry of loop, pipe diameter and thickness, ground thermal characteristics, brine composition and flow rate. On a day by day basis the only one you can affect is the flow rate and this needs to be set so as to extract heat from the ground no faster than the ground can supply it. This can be done by trial and error by monitoring the flow and return temperatures and looking for a flow rate that delivers a steady return temperature with an adequate delta T. A delta T of about 6 degrees should ensure a good COP but it would still work with a lower value.

SOR2010

ecowise wrote: »

Your outflow temperature is way to high at 8.6, it should be close to zero. Does your unit have a sight glass and can you see that the working fluid level is ok?

Yes it has a plastic Vessel above the HP (holds about 2ltr if full at a guess)
We had some issues after it was installed with it losing water/fluid and the Installers came back and fitted a valve on it to keep it topped up, Its usually around mid way on it

SOR2010

[/QUOTE]Yes going from curve 7 to 5 will make a big difference. Doing down as low as 2 will mean you will be a lot cooler in your house, if you can live that then happy days as it will be a lot cheaper for you. It's hard to give up constant heat when you get used to it.

In relation to your running times:
13% run time for hot water (average is 15%).
2 starts for every hour means you have plenty open circuits which is good.
Assuming your units draws on average 14 amps (hot water cycle and heating) and your average cost is 15c/kWhr (day rate and night rate).
I believe your heat pump has cost you roughly €5,800 since it was installed. or 38,561 kWhrs.

So if your heat pump has only done 13% (€754) of its work on hot water then you can see that when you make savings it's with adjusting down your heating[/QUOTE]


What Curve would you recommend?

The main issue we have is our first year in the house our total bill including ESB & Heating was €1500
Now it's nearly €3500 p/yr in total and there were no changes made to the settings,
And while ESB costs have risen it hasn't been on the same scale as the bill,
ie when installed night rate average was 0.12c and now it's 0.15c

ecowise

Re: working fluid: 2 ltr seems a bit large for the working fluid (refrigerant) but I am not familiar with your model. 2 ltr would suggest to me some kind of buffer but perhaps someone who knows your heat pump could comment. Our old (Solterra Genie) heat pump has a small amount of fluid and it is visible in a sight glass (about 20mm in diameter) that shows half full liquid when not operating but it disappears (vapourizes) when operating.