Howlor
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| posted on 8/10/07 at 03:44 PM |
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OT - Ground Source Heat Pumps
Anybody out there in Locost land locosted their heating? I am interested in one of these systems but just wonder how good they actually are?
Just fancy doin my bit for the environment.
Many thanks,
Steve
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tegwin
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| posted on 8/10/07 at 03:51 PM |
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We currently have an air source heatpump in opperation and have done for the last 20 years....
Granted it wasnt a lo-cost solution it works very well.... We couldnt dig deep enough to burry ground loops, so had to go air source...
IMHO, if you know a bit about plumbing and refrigeration, making a cheap ASHP wouldnt be difficult!
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iiyama
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| posted on 8/10/07 at 03:57 PM |
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Two types of ground source and Worcester would appear to be market leaders. The most effective is the most expensive, and your looking at around £25k
plus! 
IMO it aint been around long enough yet. Solar is much more cost effective at the moment.
If its broke, fix it. If it aint broke, take it apart and find out how it works!
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theconrodkid
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| posted on 8/10/07 at 04:27 PM |
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thats whai i,m doing at the mo....for a job that is,ask away
who cares who wins
pass the pork pies
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Howlor
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| posted on 8/10/07 at 05:24 PM |
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Thanks for the info guys, is 25K a realistic price for an install, if so then it's a serious payback time!
Steve
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iiyama
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| posted on 8/10/07 at 05:35 PM |
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Went to a seminar with Worcester Bosh and the touched on ground source. They talked about 2 types and as I say the most expensive is the most
effective.
They provide a service where thet supply and fit the system into the ground, (25k approx), and then you need the pumps and house side systems on top
of this.
TBH I suspect it can be done cheaper then this if you prepared to do the research and put in the time, but as I said earlier I think that solar is a
cheaper better bet in the short term. Your more likely to see you investment returned.
If its broke, fix it. If it aint broke, take it apart and find out how it works!
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theconrodkid
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| posted on 8/10/07 at 06:01 PM |
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i would say 25 grand is a bit on the low side,but then we are working on big installs,5X100 meter holes etc,i hear the temperature isnt good enough if
you like hot baths,if done wrong you can freeze the ground and cause subsidence,there is a lot more to go wrong with this system,overall i would say
dont bother
who cares who wins
pass the pork pies
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caber
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| posted on 8/10/07 at 08:33 PM |
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The effectiveness depends a lot on your ground conditions. If you have water that flows or is in underground reservoirs then you can dump a lot of
heat easily. If you have heavy clay or dry soil it is very difficult to get rid of the heat, this is what usually the economic viability of such
schemes.
Air cooled heat pumps are a reasonbly vible and easy to get, they are sold by B&Q as their airconditioning units. Most of these are reversible so
provide heat in doors while cooling outside air. They are not perfect but I have one in my office that replaced a night storage heater of 3 KW and
consumes about 1.2Kw and this is used only on demand rather than the night storage heaterthat ran for 7 hours or so every night!
Caber
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Ian D
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| posted on 8/10/07 at 08:34 PM |
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I found a web site on the subject. The issues as i saw them
1 Coiled pipe in ground needed a lot of garden. Way beyound most houses
2 It works at 40 degrees so works best with underfloor heating. Another cost and a lot of disruption.
3 Cost of install I could not see a payback
4 Require about 10% of the energy of a normal boiler.
Hope this helps
ian
Hope this helps
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oadamo
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| posted on 8/10/07 at 11:15 PM |
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where developing a small wind turbine at work at he moment to go on top of roofs there aimed at 3rd world countries but you could use them to power
small wattage heaters or somthing. there a long way off being finished but wind power is free.
adam
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albertz
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| posted on 11/10/08 at 07:01 PM |
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I have retro fitted a ground source heat pump in my last house. I have since sold that house and built another. As anyone that has built knows there
are many many choices and decisions to be made, the heating system was not a choice, it was a no brainer!!
Its fair to say that i am a fan of the GSHP system when specified by professionals and installed in the correct circumstances there is no realistic
comparison.
Basically the fundamental requirements are that the house be properly insulated, the house needs to be draught proofed (these are the same for any
efficient heating system though), the house needs a solid concrete floor and should have under floor heating to be at its most effective.
For a modern standard 250m2 house you should not be paying more than £12,000 for the complete heat pump and an indemnity backed gaurantee - if you are
paying more then contact Invisible Heating Systems Ltd http://www.invisibleheating.co.uk/
In Scotland you can get a 30% grant up to a maximum of £4000.
To meet current Building Regs you need a boiler about 97% efficient, this will cost £2000+, the oil tank costs £400 - a gshp correctly installed and
specified is about 400-450% efficient (note the emphasis on correctly installed and specified).
This technology is far ahead of air source heat pumps. Consider that with an assumed average air temperature of 8 degrees in winter, your air source
has to extract a minimum of 8 degrees to work, this means that the unit freezes and your heat pump has to use valuable energy defrosting....likewise
the air humidity and salt levels need to be carefully considered. Whereas a ground source at a minimum of 1200mm deep the temperature has very little
fluctuation between the seasons, therefore works far more consistently.
I am now quite heavily involved in the design and installation of these technologies along with underfloor heating and solar panels. To me the obvious
choices are: solid floor, underfloor heating, ground source heat pump and large thermal store tank.
Obviously these choices are subject to my location where mains gas is unavailable, the bedrock level is quite deep etc. It is not a "one suits
all" approach, but if the circumstances are right then this is the way forward in my opinion.
If anyone wants to know more or obtain a quotation then please U2U me. I have been standing on a Renewable Energies Exhibition floor stand during last
week speaking at length about the pros and cons of these systems and accept that they do not suit everyone, but they should be investigated.
When i retro fitted my first heat pump i had evidence to say that i was saving £80/month on my heating and hot water costs. The repayment period for
me was (conservatively) 5 years.
I fitted my new system within a 50x40m plot, avoiding all my surface water and foul water drains, electric cables etc, so the plot need not be that
big, although this is probably bigger than those in built up areas.
I hope this helps convince someone!
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