Sun, 17 May 2026 01:42:39 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112374#Comment_112374 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112374#Comment_112374 Thu, 30 Jun 2011 22:05:09 +0100 SteamyTea Posted By: DamonHDenvironment minister's priorities
His priorities are his estranged wife and liberty at the moment I think.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112405#Comment_112405 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112405#Comment_112405 Fri, 01 Jul 2011 13:31:45 +0100 DamonHD https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112410#Comment_112410 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112410#Comment_112410 Fri, 01 Jul 2011 13:55:55 +0100 Paul in Montreal Posted By: SteamyTeaBut back to the -10C and COP, this is not really relevant as it is an extreme event. What you need to calculate is the COP when you need the heat. This can be split into two parts, Space Heating and DHW and compared to HDDs for your area. Then pick a system that fits that profile best.

COP isn't the problem at low temperature, it's output capacity (for ASHPs). This does drop quite significantly with temperature, plus you lose even more capacity once you hit the need for defrost cycles. Sizing your heatpump for enough capacity at very low ambient temperatures could mean it's oversized for more normal conditions, leading, potentially, to short cycling. Plus a larger capacity machine will cost more. You'll have to do a calculation to find the best compromise between sizing of the heatpump versus the additional cost of auxiliary heating to cover those extreme days.

Paul in Montreal - now in cooling mode for the GSHP]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112484#Comment_112484 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112484#Comment_112484 Sat, 02 Jul 2011 18:40:09 +0100 topher
That is the point. You have illustrated it very well. I believe that some ASHP have resistance heaters built in. My GSHP has up to 9 Kw additional heat, and one day when I demanded a big increase in ambient, it cut in. It has done this only once. But why put it in a GSHP? If the pump is sized correctly it should not be needed. I told Nibe that I did not want it. But it was not an optional extra.

Status on the primary circuit pressure drop - as it dropped to 0.5 bar then rose to 0.6 bar when it got very warm - Dominique says that proves I still have an air bubble. If I had a leak, it would have dropped to zero. Seems to make sense. What is it about water and glycol? I have auto air vents all over the place, and yet air in the system after 10 months? Why?

Regards,...........Topher.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112485#Comment_112485 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112485#Comment_112485 Sat, 02 Jul 2011 18:43:10 +0100 DamonHD
Rgds

Damon]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112492#Comment_112492 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112492#Comment_112492 Sun, 03 Jul 2011 07:36:39 +0100 topher
I guess you are right. It is just one of those things. It is strange that the secondary circuit settled very quickly and is now rock solid. The primary did the same for the whole heating season, then suddenly the air bubbles have appeared. Not a big deal really, it will be solved eventually.

Regards,.............Topher.
.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112502#Comment_112502 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112502#Comment_112502 Sun, 03 Jul 2011 09:42:01 +0100 DamonHD
Rgds

Damon]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112512#Comment_112512 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112512#Comment_112512 Sun, 03 Jul 2011 14:23:52 +0100 Dantenz Posted By: topher What is it about water and glycol? I have auto air vents all over the place, and yet air in the system after 10 months? Why?
I would screw the vent caps down on the auto air vents as it may be possible that these are allowing air into the system. These devices are usually designed to operate with a much less viscous medium (water) and because the loop fluid temperature will become colder as the machine runs then the viscosity will increase.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112516#Comment_112516 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112516#Comment_112516 Sun, 03 Jul 2011 17:09:38 +0100 topher
Thanks. I am occupied with visitors at the moment. In a week or so I will re-presurise to 1.5 bar and do as you suggest.

Thanks,...........Topher.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112555#Comment_112555 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=112555#Comment_112555 Mon, 04 Jul 2011 13:10:01 +0100 djh Posted By: topherIt is strange that the secondary circuit settled very quickly and is now rock solid. The primary did the same for the whole heating season, then suddenly the air bubbles have appeared. Not a big deal really, it will be solved eventually.
I think there's another possibility that might be worrying. Are you sure that the gas is air? It's possible that it could be hydrogen generated by electrolysis (galvanic corrosion) somewhere in the circuit. I believe it's possible to test it.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113021#Comment_113021 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113021#Comment_113021 Thu, 14 Jul 2011 09:07:30 +0100 topher
The temperature of the primary started at ambient, about 22 degrees, then quickly after the pump had been running, it reached 13.6 degrees - the temperature deep underground. Before I decided to have the installation, I considered cooling in summer, I was persuaded against it because one person said that as I did not know the spacing of the underfloor pipes, I might have 'stripes' of cold floor with condensation. As my floor tiles are very slippery when wet, I decided against it.

Now I am thinking again - how much would it cost to put in a valve to link the two circuits, and get more antifreeze to put in the primary circuit - it should not be too expensive, and very cheap to run.

I know that Paul in Montreal has his system in a cooling mode. I would be interested hearing comments from Paul and anyone else who has such a system. Does it really work? Do you have condensation problems? Does it have any form of temperature control?

Regards,...........Topher.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113038#Comment_113038 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113038#Comment_113038 Thu, 14 Jul 2011 14:03:24 +0100 Paul in Montreal Posted By: topherI know that Paul in Montreal has his system in a cooling mode. I would be interested hearing comments from Paul and anyone else who has such a system. Does it really work? Do you have condensation problems? Does it have any form of temperature control?

My system uses forced air, not UFH so there's no problem with condensation. It works very well for air conditioning as it's cheap to run (COP is very high because the ground is cold) and it removes a lot of humidity from the air, which is the main problem here, rather than the temperature, though we've been staying in the low 20s overnight for the past couple of weeks now. For temperature control, we use the same thermostat as for heating. It's currently set to 21C - this sounds cold but the thermostat is downstairs where there's very little solar gain - the upstairs gets much more sun and is consequently a lot warmer - before we had the system installed the temperature in the bedrooms in summer would be in the mid to high 30s, even with the windows open at night. Now with the system running and the thermostat at 21C downstairs, it's a pleasant 23-24C upstairs (a bit lower if I let the air circulate continuously).

I doubt using UFH in cooling mode would work in my climate due to the humidity - for a desert climate it can work well as far as I understand.

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113647#Comment_113647 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113647#Comment_113647 Mon, 25 Jul 2011 08:54:17 +0100 topher
For the entire 10 days, the temperature of the primary circuit was 13.6 degrees. I wonder if this tells me anything about the COP that I will get when I first turn it on. Is there a 'guide' formula which shows how the COP varies with primary temperature, temperature difference, secondary, and secondary temperature difference? Anyone know?

Regards,.........Topher.
.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113648#Comment_113648 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113648#Comment_113648 Mon, 25 Jul 2011 09:09:20 +0100 Sprocket You can easily calculate the Carnot Limit for different temperatures.
If you assume your heat pump always returns a fixed proportion of that then it is very easy to pop the numbers into a spreadsheet and what comes out is pretty interesting.
What I don't know is just how 'loose' an approximation this fixed proportion part is.
I did this a while ago out of curiosity. I'll see if I can find it.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113652#Comment_113652 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113652#Comment_113652 Mon, 25 Jul 2011 10:35:40 +0100 Sprocket Substitute your own GSHP COP at 35 degrees and your own brine and UFH flow temps.
Make of it what you will though, it was just an experiment.

Ah - GBF won't let me add an attachment. Why is there a button for it then?
If you can whisper me your email address I can email it.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113724#Comment_113724 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113724#Comment_113724 Tue, 26 Jul 2011 16:00:58 +0100 gustyturbine Gusty.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113746#Comment_113746 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113746#Comment_113746 Tue, 26 Jul 2011 21:47:48 +0100 Sprocket
We're in Somerset.
I don't really know. It's dissappointing that the domestic part isn't up and runnning yet.
The premium payment (a one-off subsidy for installation if I understand correctly) is about to start. You can "register interest" over at the Energy Savings Trust website (they will admin the scheme IIUC) but you can't quite claim it just yet. Expected next month is last I heard for that.
But the full incentive for domestic users looks like it won't happen until next year now.
Only info on tarrifs is things like this (and still could change before it starts):-

http://www.rhincentive.co.uk/eligible/levels

Looks like 7p/unit for 23 years is best guess to me.

Someone else here hopefully knows more?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113780#Comment_113780 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113780#Comment_113780 Wed, 27 Jul 2011 13:24:38 +0100 gustyturbine we will see what eventually happens then?
Gusty.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113856#Comment_113856 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=113856#Comment_113856 Thu, 28 Jul 2011 13:13:38 +0100 Sprocket I cant see that this government has much to gain by changing those proposals much... not compared to solar-pv anyway. Our install costs for heatpumps are not changing much. Neither are there 1000s of people rushing to set up heatpump farms and claim massive subsidies.
There is a "Any news about RHI" thread over in the renewables forum here.
Which reminds me - I had a question to ask about solar over in that topic too.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114063#Comment_114063 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114063#Comment_114063 Tue, 02 Aug 2011 08:53:53 +0100 topher
He has proposed a heat exchanger and a 3 way valve. This has the advantage of keeping the primary and secondary separate and the motorised 3 way valve can be use to control the flow of cool water to the underfloor.

I am hoping to get a price for the work, and who knows it might be done in the winter time ready for next summer.

I would be interested in your comments. Regards,..........Topher.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114085#Comment_114085 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114085#Comment_114085 Tue, 02 Aug 2011 13:27:59 +0100 SteamyTea Or were you after comments of the speed it may take to be fitted ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114101#Comment_114101 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114101#Comment_114101 Tue, 02 Aug 2011 15:42:10 +0100 topher
Sorry for poor communications. I was wondering if cooling the floor would help in improving the house comfort in warm and/or humid weather. I would circulate cool water - around 15 degrees in the underfloor pipes. This would cool the large lumps of concrete that are the ground floor and the first floor. The house has very thick stone walls with additional internal insulation. It would not reduce the humidity, and perhaps when the humidity was high, water might condense on the cool floor causing falling down accidents!

Today the weather is cloudy, rainy, thundery, and a bit humid, but not too unpleasant.

The temperature just above the floor is 23 degrees and the RH is 68%.

Regards,.............Topher.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114128#Comment_114128 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114128#Comment_114128 Wed, 03 Aug 2011 09:27:05 +0100 djh Posted By: topherI was wondering if cooling the floor would help in improving the house comfort in warm and/or humid weather. I would circulate cool water - around 15 degrees in the underfloor pipes. This would cool the large lumps of concrete that are the ground floor and the first floor. The house has very thick stone walls with additional internal insulation. It would not reduce the humidity, and perhaps when the humidity was high, water might condense on the cool floor causing falling down accidents!

Today the weather is cloudy, rainy, thundery, and a bit humid, but not too unpleasant.

The temperature just above the floor is 23 degrees and the RH is 68%.
According to http://www.decatur.de/javascript/dew/index.html the dewpoint is 14.82 C, which is rather close to 15 C!

So whether you would get condensation or not depends on how lucky you feel

It sounds like you would definitely get condensation on days when it does feel unpleasant. I think that's one reason why air-conditioners cool the air rather than surfaces.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114139#Comment_114139 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=114139#Comment_114139 Wed, 03 Aug 2011 12:57:49 +0100 topher https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=115724#Comment_115724 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=115724#Comment_115724 Tue, 30 Aug 2011 09:17:35 +0100 topher
I am now on my third leak in the primary circuit. The first was some time ago, during the heating season, and was caused by a broken pipe fitting in the manifold connecting the black high density polythene pipes from the bore holes to the main flow and return to the heat pump. The broken fitting was caused by over tightening or defective brass in the fitting. The installer claimed the latter, everyone else said it was the former!

The second was during the summer - there was a sudden loss of pressure. It was thought to be an air bubble because when the pressure was restored and the circulation pump run for 10 days, the pressure stayed up.

About 8 weeks later, I noticed that the pressure was zero again. This time I could not get more than 1.0 bar because I ran out of the pink antifreeze. When I looked at the manifold, it was surrounded by the pink coloured water. I am now waiting for Dominique to find the leak and repair it.

The inspection chamber is about 60 centimetres deep and has a small cover. It is very difficult to work on the manifolds because the space is so restricted and the pipes are very stiff. Four smaller pipes are connected to one big one and one manifold lies on top of the other. I am going to have a much larger inspection pit made, since it seems to need frequent visits.

In hindsight I should have insisted on a plastic manifold with the pipes heat welded together. It might have been more expensive, but it would have been much more reliable. I am not sure about a pressure test, because the pressure has held up for weeks between failures.

If you are having pipes jointed underground, I would strongly recommend all plastic fittings with the pipes heat welded. It would be interesting to read about other's experiences.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=115729#Comment_115729 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=115729#Comment_115729 Tue, 30 Aug 2011 09:55:12 +0100 DamonHD
If you're going to be away for extensive periods you might need some backup, eg electric oil-filed heaters set very low as frost protection.

Rgds

Damon]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=115730#Comment_115730 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=115730#Comment_115730 Tue, 30 Aug 2011 09:56:12 +0100 gustyturbine Gusty.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=115743#Comment_115743 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=115743#Comment_115743 Tue, 30 Aug 2011 14:15:46 +0100 topher
Gusty, Lucky you with your modern manifolds.

I am having dream thoughts about selling this house and having a new one built with the proceeds. It would have underfloor geothermal heating of course. I was wondering about having free cooling in the summer using the 'cool' water from the boreholes.

Dominique tells me that there is a product called 'VMC double flux'. I think this translates to something like mechanical ventilation with heat recovery (MVHR). It can supply and extract air to all (most) rooms in the house. So for example, the bathroom is hot from someone having a bath, the warm air is extracted and passed through an air-air heat exchanger. The resultant warm, less humid air is fed to other rooms to supplement the heating. It would have a water-air heat exchanger with the bore hole antifreeze (@ 13 Deg) pumped through, this would supply cool air to the rooms in summer.

Now, if I could afford a swimming pool too, it could have a water-water heat exchanger which could heat the pool in summer and allow low temperature heat to be taken in the heating season. Would this be worthwhile or would the pool rapidly give up its stored heat in winter?

Dreaming is great eh?

Regards,.......Topher.
.
This might be helpful http://en.wikipedia.org/wiki/Heat_recovery_ventilation]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=116317#Comment_116317 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=116317#Comment_116317 Tue, 06 Sep 2011 20:25:46 +0100 topher
Dominique came today to investigate the third leak. It was found to be a brass fitting. What I would call a straight one inch coupling, male to female. The flow and return manifolds are made up with one of these on each side. If you look at picture 10, dated 5 October 2010 you will see it. It is on the right hand side next to the elbow. So now both the flow and return have had the same fault. You can clearly see the crack on the fitting. I hope to post a picture in a few days. Both fittings have had the same longitudinal crack. So I seem to be the unfortunate recipient of two defective machined brass castings.

Dominique has taken the fitting to his supplier to complain. He has borne the cost and time of making two repairs because of these defective parts.

The system now has the primary pump running 24/7 for a few days at 1.5 bar. Fortunately there is a builder on site doing various projects. Tomorrow he will construct a new inspection pit, much larger than the old one which will make any future leaks much easier to fix.

P.S. Have you guys come across a 'Puit Canadianne' or earth tubes? There is a section on this forum. Very interesting. Almost free cooling in summer and almost free base heat in winter. Not expensive to install in a new build. Have a look at . . . .
http://www.builditsolar.com/Projects/Cooling/EarthtubeNotes.htm
http://www.greenbuildingtalk.com/Forums/tabid/53/aff/14/aft/58831/afv/topic/Default.aspx
http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=1026&page=1#Item_0]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=123789#Comment_123789 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=6164&Focus=123789#Comment_123789 Thu, 24 Nov 2011 13:23:11 +0000 topher
I am not sure if anyone is reading this. If you are, please say so.

I got back to the house a few days ago. The heat pump was off and the interior temperature was 14 ºC. I put the heat pump on, and in the usual 3 or 4 days, it climbed to the set figure of 19 ºC. If you have been reading this, you will know that I have had a lot of leaks in the primary. So far the pressure is holding at one bar - hooray. Lets hope the leaks are finally fixed.

I noticed that the temperature difference on the primary was higher than usual. I took out the filter on the primary circuit that stops the crud going into the heat exchanger. It was 50% or more blocked. I cleaned it and the temperature difference dropped to the usual 5 ºC. I believe that this has made the heat pump more efficient as it can now abstract more heat from the ground.

If you have a system with a filter in the primary, it would be interesting to know how clean it is, and if after cleaning, the temperature difference is less.]]>