Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

Buy individually or both books together. Delivery is free!


powered by Surfing Waves




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




    • CommentAuthortopher
    • CommentTimeAug 17th 2010
     
    Next week (23/8/2010) the installation of a ground source heat pump will start at my house in Western France. I have had one person say that he would find it interesting, so as an extrovert I am happy to oblige. I have started a new thread, but if I have put it in the wrong place, I am hoping a moderator will correct my error.

    I am hoping that some people may give me some tips to save me money and time. I am happy to answer any questions that arrive.

    It is a 15 KW 3 phase heat pump made by Nibe in Sweden, but badged as Atlantic - the distributor in France. It will be supplied by two 100 meter vertical bore holes drilled through water courses, but will use a closed circuit supply of two pipe loops per bore hole.

    Wish me luck!
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 17th 2010
     
    Bonne chance! B^>
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 23rd 2010 edited
     
    Hi,

    Topher's been whispering some stuff to me that was meant to be public, so to save some typing I'm cutting and pasting some of it back here:

    Report 1:

    Of my two bore holes one is 102 meters the other is 95 meters deep. Both will
    be connected to a manifold, then from the manifold to the heat pump in the
    house. I am keen that the pipe lengths to both bore holes are equal, so that
    the flow to both bores are equal to get the best possible heat transfer. So the
    horizontal trench for the 95 meter deep bore hole needs to be 7 meters longer
    (102 - 95 = 7 meters). I am hoping to get this by having a zigzag trench from
    the 95 meter bore hole. Just one zig, not too difficult.

    and

    Report 2:
    Work started today. A huge amount of stuff arrived. Fittings, inertial
    cylinder, many containers of antifreeze, and so on. The trench route question
    has been solved. The lengths of the pipe runs to the bore holes will be be the
    same, there will be just a short length of trench where all 8 pipes from the
    boreholes will be together. I have told my French Heating engineer about this
    blog and he is going to read it. Who knows he might even contribute a bit too.


    Rgds

    Damon
    • CommentAuthortopher
    • CommentTimeAug 24th 2010
     
    24 August 2010. Report 3.

    Due to the house layout, the best position for the heat pump and 200 litre inertia tank is in a loft space on the first floor. There is plenty of room in the loft space, but it needed 5 people to lift the heavy heat pump up the stairs. This was done with efficiency and good nature by the team.

    Today, Dominique and Pierre are connecting lots of pipework. Tomorrow a new person will be digging the trenches for the borehole pipes to be connected to the manifolds and then through the wall, into the house and up into the loft space. I will be connecting a 'Current Cost' energy monitor (Model CC128 ENVI) to the three phase supply to the heat pump. I hope to record every single watt that it consumes
    • CommentAuthortony
    • CommentTimeAug 24th 2010
     
    I hope that you set it on a resilliant base to minimise sound transmission and vibration.
    • CommentAuthortopher
    • CommentTimeAug 24th 2010
     
    Tony, Yes, I am very aware of the huge loudspeaker that the floor of the roof space makes to the visitor's bedroom below. Previously I was planning to have a heat pump made by a French Company called GĂ©oThermic. I visited the factory and listened to the noise it made, it was significant. I was planning to have it mounted on hangers on the very solid wall (1 meter thick) with insulating pads. I also visited a neighbour who had a very noisy heat pump (much louder than a fridge) in their kitchen. They were annoyed about the noise, but had grown used to it.

    Then I discovered Atlantic - they import Nibe heat pumps from Sweden. I was able to visit the classroom where they teach installers about the product. Using the inaccurate measurement of my ears, they are as quiet as a fridge. The compressor and heat exchangers are inside a sealed metal box. It must have a great deal of sound insulation. The heat pump will be on additional sound insulating feet on a thick base of high density chipboard which will be on the floor of the roof space. The Atlantic spec says the noise level is 21 dB(A)

    I hope I will have a quiet heat pump. Wish me luck.
  1.  
    Posted By: topherI will be connecting a 'Current Cost' energy monitor (Model CC128 ENVI) to the three phase supply to the heat pump. I hope to record every single watt that it consumes


    If your aspirations are to record every watt (or even close to it) of consumption then you might want to check out http://www.navitron.org.uk/forum/index.php/topic,11527.0/topicseen.html regarding the accuracy of the CC128.
    • CommentAuthortopher
    • CommentTimeAug 24th 2010
     
    Mark, Thanks. I will have to accept a less accurate measurement than I had hoped for. However I am comparing with propane gas which a year ago cost me (assuming my maths are right) 0.108 €/Kw Hr. With my old gas boiler (estimated efficiency 70%) that comes up to 0.1543 €/KW hr. I was using on peak electricity* at 0.0495 €/Kw hr in place of the gas. So if my heat pump has a conservative efficiency or COP of 4.0 then 1 Kw of heat will cost me 0.0124 €/Kw hr. To good to be true eh?

    I hope to find out.

    * EDF (French sole domestic suppler of electricity - 85% nuclear) have a brilliant tariff called Tempo. The prices given above are for the summer daytime rate - night is even cheaper. But they can really whack you in the winter time when on some days the cost is 9 x the summer rate. If you are interested, look at http://www.frenchentree.com/france-lot-quercy-services-contacts/DisplayArticle.asp?ID=10263
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 24th 2010
     
    Yes, I think the Tempo tariff is very interesting: time for us Anglo-Saxon capitalists to adopt some of your French exposure of consumers to real costs ... eh wait ...

    Rgds

    Damon
    • CommentAuthortopher
    • CommentTimeAug 24th 2010
     
    Damon, Yes Tempo is very clever. If you were running a nationwide electricity company and did not want to have excessive capacity (= expensive generators) just for the odd peak demand, you would invent a way of discouraging the peaks. In the UK the big users have price which varies with demand. EDF just look at the weather forecast and if it is going to be cold, declare that tomorrow will be a red day. I am sure they have a max demand pricing for the big users too.

    Imagine all the French domestic users getting the news that tomorrow is to be a red day. The price is now going to be about 9 times normal. Do the ironing another day, wash up by hand, turn the imersion off it will probably just last for 2 days before a reheat, cook on the gas hob, not the electric oven . . . . and so on.

    It is done with an electronic consumption meter. EDF send a signal to tell it what tariff to use. The whole thing is entirely in the interests of EDF, but has some benefit for the users too. The year when I switched to Tempo, I got a rebate of about 100 €.
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 24th 2010 edited
     
    EDF here in the UK has a sensible tariff (but much simpler) that gives normal rates all day but a 20% discount out of peak hours (say 9pm-6am and all weekend) IIRC.

    But we need more like Tempo that engage consumers with real costs and/or reward those that are careful and cooperative. We will all benefit in the end in reduced infrastructure and fossil-fuel costs.

    Rgds

    Damon
  2.  
    I work for EDF as an asset manager (wind farms) and I agree 100%,
    Gusty.
    • CommentAuthortopher
    • CommentTimeAug 26th 2010
     
    26 August 2010. Report 4.

    In the garage are eight 20 litre containers of antifreeze for the borehole circuits. The heat pump supplier recommends protection to minus 15 degrees Celsius. Some of the containers are pre mixed at 33%, others are neat glycol. The glycol manufacturer says that a 30% mix gives protection to - 15 Degrees C.

    I took a sample of the 33% mix and put it in the freezer. My freezer has -16, -18, -20, -22, and max settings. I do not know how accurate the control is. At -16 and -18 it stayed as a bright pink liquid. At -20 it has now become a slush.

    Normal winters here get to -4 or -5 degrees, but mostly hover around zero. My neighbour who has been here a long time, said that once it got to -15, but that was very rare. So I think it will be OK.

    The borehole installation is covered by AXA insurance for 10 years. I was surprised to see that they do not demand a certain antifreeze concentration.

    Trenches were supposed to be done yesterday but the digger driver was not available. He is here today, and my rather badly maintained garden is being destroyed. It will re grow.
    • CommentAuthormoggeridge
    • CommentTimeAug 26th 2010
     
    Sounds like your driller is pretty honest admitting one borehole is not as deep as it should be - very good sign.

    15kW from essentially 2x100m boreholes is a big ask. Twin loops will help to a degree but you are expecting 75w/m. This is normally only achieveable in the very best of scenarios. I would ask who designed your ground loop what ground conditions they were expecting and also what minimum entry water temperature they have entering the heat pump. One other question would be the grout - is it thermally enhanced. Also, check that the boreholes are well spaced (with the load I woud expect 10m or so).

    Hope all goes well for you.

    Regards

    Mike
  3.  
    Posted By: moggeridge15kW from essentially 2x100m boreholes is a big ask.


    Sounds bang on the money to me - this is 150 feet per ton of capacity which is the standard for vertical loops over here in Canada (assuming rock rather than sand or clay for the boreholes). Just to be clear, the holes themselves source about 3/4 of the 15kw, not 100%. For example, if the COP is 4.0 (optimistic) then the boreholes will supply 11.25kW and the other 3.75kW will be supplied directly by the electricity running the compressor.

    Agree about using proper grout and making sure the holes are spaced far enough apart and getting specs on the entering and exiting loop temperatures. All these figures should be part of the start-up procedure for the system so that you know it's "running right".

    Paul in Montreal.
    • CommentAuthortopher
    • CommentTimeAug 26th 2010
     
    Mike and Paul,

    Thanks for your comments. Very interesting. Let me tell you some history and some facts.

    First, the Atlantic France (really Nibe in Sweden) 15 Kw heat pump manual says it needs two boreholes of 100 to 120 meters depth. It was me that said that I needed 2 x 100 meters, this is because I was dealing with GeoThérmal, the previous supplier and they said 2 x 100 meters for a 12 kw heat pump. I missed the point that with Nibe, I was on a 15 kw machine, and it might need more. My mistake. Doh!

    It was easy to see that one bore hole was 95 and the other was 102 meters because the pipe is marked with its length, every meter, from about 5 meters (next to the 'U' bend) to 120 m at the opposite end. The bore hole driller told me that the first hole was 98 (he misread 95), so he drilled the 2nd hole to 102. Not bad really.

    Going downward from the shallow topsoil, first is bright red clay to about 15 meters, then it is gray shale and some layers of quartz. The two boreholes are about 15 meters apart and both were drilled where there was an aquifer - I had a water diviner (cost me 65 €) to tell me where the water sources were, and he was right. Hooray! Water is at a depth of about 40 meters and the flow is 3 to 5 cu meters per hour - I have the exact numbers somewhere.

    The other interesting thing is that the company that bored the holes put in a shorter 5th pipe so that water could be added if the bore holes became dry. My installer will put in inspection covers so that I can add water from a garden hose if needed. I am hoping that both bore holes are always wet, giving good heat transfer. The bores are not grouted, it is not yet current practise in France, and I was unaware of the process or its advantage until recently. I understand that next year it will be compulsory here. However they did seal the top of the borehole with a special product which expands when wet and forms a seal. It is wet.

    So with fingers crossed, I hope I might be able to get enough heat from the ground.

    The heat pump COP is quoted as 4.25 at 35 deg Celsius. I have underfloor heat so I will run at 35 deg or less. At 35 deg, the heat output is quoted at 15.42 Kw. So if I understand correctly, I will take 15.42/4.25 = 3.63 Kw from the electrical supply and 15.42 - 3.63 = 11.79 KW from the 95 and 102 meter bore holes.

    I will be very interested in your thoughts. Regards,..........Topher.
    .
    • CommentAuthortopher
    • CommentTimeAug 27th 2010
     
    27 August 2010. Report 5.

    The garden is now totally destroyed - just the rather poor quality grass bits, the flower beds remain intact. I had expected it, but when you actually see it happen it is a surprise. Trenches have been dug that slope downwards towards the bore holes; at the deepest they are 2 meters deep rising to say 0.5 metes as they enter the house. Today the 8 pipes from the bore holes will be laid in the trenches, they will be filled with antifreeze, then connected to the heat pump via the manifolds. I have pics if anyone is interested.

    They will be topped up with antifreeze and pressurised with a pump as the circuit is closed. Dominique the boss will not allow a connection to the bore hole circuit for refilling with mains water in case of diluting the antifreeze. It makes sense. If I need to top up, I will have to buy a pump and get some correctly diluted antifreeze.

    The Nibe heat pump has a control that allows the primary (bore hole) circulation pump to run 24/7. This will be useful to ensure all the air has been bled from the circuit. Later on it can be set so that it starts 20 seconds before the heat pump.

    The heating circuit is almost complete. They are going to flush it out with mains pressure before filling with water and inhibitor.

    It is 9.15 am and Dominique is hopeful that the pump will be switched on today. I am doubtful, we will see.
    • CommentAuthortopher
    • CommentTimeAug 28th 2010
     
    28 August 2010. Report 6.

    I was right. Installation was not completed on Friday evening as planned. However, Dominique worked his socks off pushing himself very hard all day long. There was power cut in the afternoon, heavy rain in the morning, and a broken underground rainwater pipe to be repaired - not helpful.

    Each bore hole loop is filled with the pink antifreeze mixture. When the pipe loops were put down the bore holes, the drillers put water in the pipes to make them heaver and assist their descent. At this stage of the installation, a small electric pump is used to force the pink mixture into the pipe. When clear water coming out the other end, turns pink, both ends are sealed. The next step will be connection to the manifold. Fortunately each pair of pipes has one plain and one with a longitudinal stripe. In this way, as long as all the stripes are connected to one side of the manifold, and the non-stripped to the other side, all will be well. Finally antifreeze will be pumped by hand into the closed system and the circulation pump started. Air will be bled out of the system and the correct pressure set.

    The neat glycol has to be premixed with water before being put in the pipes. Apparently if neat antifreeze is put in the pipes and expected to mix with the existing water, it does not. Slugs of antifreeze circulate with slugs of water. This is not like adding inhibitor to a radiator circuit.

    Work will re-start on Monday and take 2 or 3 days I expect. I am concerned about the garden being left in the best possible state. The trenches have taken up lots of space and clearly they will have the bright red clay surface. I would like the non trench areas restored as well as possible. There are some piles of soil - for example near the bore holes where the fine material was pushed out from the drilling process. I am hoping I can get Dominique to encourage the digger driver to do the best he can to get a good result.

    When the installation is finished and the heat pump commissioned, a stage payment is due. The final payment will be made on the 1st December when the system is working correctly and keeping the house warm.
    • CommentAuthortopher
    • CommentTimeAug 29th 2010
     
    People have asked for pics. I tried to upload one. It failed. The system was not helpful. Anyone know if it can be done and how. Thanks.
    • CommentAuthorfridihem
    • CommentTimeAug 29th 2010
     
    Interesting that you are using a Swedish NIBE heat pump. A close neighbour here in Sweden installed a Thermia pump last summer 2009, but he only used ONE hole, about 120 meters, which was drilled the first day, no problems as the going was good thru granite. The second day the piping was installed in the hiole and into the house, pump connected etc etc etc, and on the 3rd day it was up and running. For the first year up until the end of July 2010, it took approx 3000KWh for running, and supplied heating for the house, water rads, and hot water. He has about 170 sq meters , ground floor plus basement. Tap water is about 72C, and the pump runs for about 1 hr each day during the summer months to top up the hot water cistern. Last winter was our coldest since 1986, and we had below zero for about 3 months. He estimates he will get his money back inside 7 years at this rate
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 29th 2010
     
    That makes me think that my postage-stamp garden my not be useless for GSHP. Access for equipment could still be fun, but as our garden has a substantial car-park in front of it (about 1m above the level of our garden as it happens) so there will never be any trouble fighting with others for solar replenishment of the heat. Drilling one bore-hole shouldn't be insurmountable.

    Now all I want is an instant combi style, pref R744/CO2/Eco-Cute (ie low GWP of the refrigerant and high DHW/CH temps without immersion back-up), and we're golden.

    Rgds

    Damon
    • CommentAuthortopher
    • CommentTimeAug 30th 2010
     
    Damon,

    I don't know the geography of your house and garden, but just as an idea for you to consider - the whole area around the house might be suitable for drilling the bore hole (the driveway?). The pipes to the house can go over or under existing services like gas, electricity, and so on. Once the pipes are in place, everything can be restored, you just need an inspection cover to view the manifold.

    The only place I was not allowed to drill was within a certain distance of the septic tank and its filter bed.
    • CommentAuthortopher
    • CommentTimeAug 30th 2010
     
    30 August 2010. Warning.

    I have learned something today that I wish I had known before. If you are having ground source put in an existing house, plan very carefully the clearing up of the site afterwards.

    If one contractor is doing both the borehole and the heat pump installation, it will be easier. The trap I fell into was that the hole boring people said that all the material that came out of the bore hole would be used by the people that dug the trenches as it was a fine sandy consistency and would go well with the pipes. Now the people doing the trench say that the hole boring people should have removed the material from the bore holes.

    I am trying to get Dominique to give what was once a poor grass area the best possible tidy up before leaving. We will see the result in a few days.
    • CommentAuthorevan
    • CommentTimeAug 30th 2010 edited
     
    Posted By: topher
    It is done with an electronic consumption meter. EDF send a signal to tell it what tariff to use. The whole thing is entirely in the interests of EDF, but has some benefit for the users too. The year when I switched to Tempo, I got a rebate of about 100 €.


    In Scotland at least there is a system called "Total Control" which uses a radio signal to turn on/off groups of domestic storage heaters and immersions to manage capacity and load. This supply is separately metered and has a lower unit price.
    Even though we have a good amount of "peaking" hydro and pumped storage, it is beneficial for them to do this.
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 30th 2010 edited
     
    Topher: our plot is so small we don't even have a driveway, and we sit on top of a web of the local sewage pipes!

    But I'm fairly sure that we could accommodate 1x100m borehole somewhere! I might even buy an underused 1mx1m bit of unused land next to us (to use) from the council for example.

    Rgds

    Damon
    • CommentAuthortopher
    • CommentTimeAug 30th 2010
     
    Damon: Good idea. When the hole is drilled, quite a bit of spoil comes out. My bore hole driller did not have a means of removing the spoil, but I think such machines do exist. In any case a bloke with a wheelbarrow and a skip would probably work. The footprint of the spoil would be bigger than the 1m x 1m that mention. May be borrow a bigger space for the spoil, then hand it back when the site is cleared.

    When the drill is working, it is not safe to stand very close. Soil, stones and perhaps water (in my case) come shooting out up to 15 feet in the air. Is is the powerful compressor that causes this.

    You should research the ground down to 100 meters to find out what it is. Different soils have different thermal transmission characteristics, may be you wont need 100 meters, maybe you will need 120 meters.

    The trench that takes the pipes to the heat pump will be 1 to 2 meters deep rising to half a meter as they enter the house. This size of trench means that you will have a lot of soil to deal with; much more than the boreholes, unless the trench is very short.

    Amicalement,...........Topher.
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 30th 2010
     
    Indeed, and just had a discussion with my SO as a front-garden and kitchen remodel is overdue given all my 'green' projects that have taken priority so far!

    (Actually getting rid of the spoil may cost us ÂŁ50/tonne if it has to be landfilled, I'm not sure what the going rate is here.)

    And we'll have the bloke move his Rolls-Royce out of the car-park while we're having fun with flying rocks. We've got to avoid my solar PV on the roof...

    Anyhow, having dismissed GSHP as impossible for us, this thread is making me think seriously about it again! This is why the detail is useful IMHO.

    Rgds

    Damon
  4.  
    It's definitely possible. Here's a photo of the drilling machine in the front of our house. We also didn't contract the clear-up of the drilling debris (due to ignorance) ... ended up shifting about 20 barrow-loads of gravel-sized rock - luckily the alley between us and the lower neighbour (which had got covered with a slick of clay from the drilling) was the recipient of all of this - solving the disposal problem and the slick all at the same time.

    Paul in Montreal.
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 30th 2010
     
    Hmm, but if you were to see that we have no easy direct road access, though we are within a couple of metres of a car-park, you'd see what was making me hesitant... B^>

    Rgds

    Damon
    • CommentAuthortopher
    • CommentTimeAug 31st 2010
     
    31 August 2010. Report 6.

    We are at the beginning of day 7. Virtually everything is connected up. The primary (bore hole) and secondary (underfloor) circuits are pressurized to just over 1 bar. Outside the inspection chambers for the two bore holes and the manifold remain to be completed. Dominique worked hard on the digger yesterday to try and make the site as good as possible. There is lots for us to do to get it flat and in a state for the grass to regrow.

    The heat pump (made by Nibe, Sweden) is not yet connected to the supply. It has a very super little facility - three current transformers for the three phases, they go over the incoming supply wires to the house. The heat pump is set with a max incoming current value, which is the same as the rating for the supply. If the heat pump load were to cause an over current, hence a blackout in the house, it reduces and redistributes supply across the phases to ensure that the max current is not exceeded. Cool eh? Only on the 3 phase machines.

    In France, one factor that affects the tariff is the max Kw of the supply. If you exceed the max, it trips, and you have to switch off the offending device before re-closing the circuit breaker. Some people have relatively low supply to save money and do their load regulation manually. When we bought the house we had a 12 Kw (3 phase) supply and would ofter exceed the max of 4 Kw per phase. When we switched to the Tempo we upped it to 18Kw and now have no problems. It is another example of the way the French control their maximum demand.
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press