The Accidental Smallholder Forum
Smallholding => Renewables => Topic started by: HappyHippy on January 09, 2011, 11:01:00 pm
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My dad's friend is thinking about putting one in to run a central heating system and my dad's considering it too (madness since we've got all this wood, but what can I say ? ::))
So, what are your thoughts ? Has anyone fitted one, how expensive and effective are they, can you give me any links to good companies or just any kind of input would be really helpful.
Thanks folks :-*
Karen
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I would say they are only any good on a modern house that is built with super insulation as they are only background heating. Watch the leccy as well, again only a modern house built around them will have suitable leccy standards.No good for older houses. If you have a modern house thats diferent.
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Sorry to disagree, Hermit. We have a GSHP in our house built in 1887. We have underfloor heating downstairs and radiators upstairs. To be fair, we did a major renovation which involved improving all insulation because the heating runs at a low temperature. If Dan comes on, he'll comment on the technical stuff. We haven't got it running right yet but will do.
Contact the Energy Saving Trust for impartial advice.
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If you did a major restoration that is what it needs, not as simple as just buying the system. A modern house or a modernised house I should have said. Some folk up here have also had to get planning permission first as well, one lady I know was refused.Not trying to put people off but there is more to to Ground Source than meets the eye. It is not that much cheaper to run either as leccy bills go up. The pros and cons need to be weighed up for each property, some systems work well others have been a waste of time.
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You would have tp be able to put in under-floor heating (and have suitable flooring for it, solid wooden floors are not possible) and it would need serious re-jigging of all your water/heating pipes. You would also need a generator for back-up in case of power cuts.
We did consider it when we built our house, but the cost of installing did put us off.
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Yes, ours was part of a major refurbishment and we have PV cells to generate the electricity. The underfloor heating is wonderful though ;D
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You would have tp be able to put in under-floor heating (and have suitable flooring for it, solid wooden floors are not possible) and it would need serious re-jigging of all your water/heating pipes. You would also need a generator for back-up in case of power cuts.
We did consider it when we built our house, but the cost of installing did put us off.
Sorry but none of that is true. You don't need underfloor heating just because you have a GSHP - I have friends who use normal rads with theirs, with great success. Also you CAN have wooden floors with U/f heating - I did just that in the house I built with no problems at all. You do need to use shorter cleats and at a steeper angle though.
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All very useful info and points of view folks, much appreciated :-*
Keep it coming ;)
Karen x
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Yes, we run radiators from ours, but I think you need to boost the heat using an immersion. The GSHP only heats the water to a lower temp than is needed by radiators.
Actually, the underfloor in our house is under terracotta, encaustic and engineered oak. We also have u/f, but electric, under slate in the bathroom. I think it's better under the tiles than the wood. It actually feels warm underfoot, where it's not so obvious under the wood.
You can put u/f under solid wood, but it has to be properly fitted, as Annie says.
We've got a wood burner in the living room as backup heating.
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We put a GSHP in 3 years ago, with u/f heating up stairs and down, the ground floor is slate and takes less energy to heat than up stairs which is wood. It costs us about £600 ayear to heat 240sq mtr and thats on 24/7. And with the govements renewable heat incentive, for a 3 bedroom terrace house you could get a £1000 ayear for the next 23 years
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Just to cover a few basic points. The ground source heat pump idea has been around for more than 50 years. It's like a refrigerator working in reverse. Instead of using a compressor to cool the inside of a box with the extracted heat going to a finned pipe on the outside, the heat is inside and the cool bit is outside.
This all works by compressing a special gas. The gas gets hot when compressed and cools when it is allowed to expand. Hence the system's ability to 'pump' heat by using a compressor.
The compressor - like a fridge - is normally driven by an electric motor but it could be driven by a car engine, windmill or steam engine if that happened to be the best source of power. Staying with the electric motor, the system effectiveness is measured by how much heat is delivered compared tot he amount of electricity used to drive the motor. So if you have a performance of 4, the system delivers 4Kw for each Kw used by the motor. This measure is called the 'Coefficient of Performance' look this up with Google if you want more information.
The important point is that this measure can be increased if you have a local source of heat like a stream. So you don't have to get the heat from the ground. Water is a good source of heat.
One of the first big heat pump installations in the UK was the then newly opened South Bank complex in London (c. 1950). The pump was a Merlin engine (as used in the Spitfire and Lancaster) using the supercharger as the compressor. The heat source was the river Thames. It had a Coefficient of Performance of 6 so it was a very good system. However, it was noisy and required a lot of maintenance so it was replace with a conventional boiler system.
With a domestic system, it would be a good idea to regard the compressor as requiring replacement every 10 years, like a fridge they don't last forever. Also, the special gas would need to be checked, topped up or replaced every year. This all adds to the overall cost of the system
If you happen to want to run your own generator driven by an engine burning LPG, red diesel or old cooking oil, you can recover a lot of heat from the engine without the need for a heat pump. But you have to consider the noise and maintenance questions as well as the cost. If you need 10Kw of electricity (continuously) it would be easy to recover 10Kw of heat, enough for a small house from the engine's cooling system. If you collect heat from the engine exhaust by putting a water jacket on the exhaust pipe, you could increase this to 15Kw of heat for 10Kw of electricity.
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If it's a choice between electric heating (conventional) and a heat pump then the heat pump is definately the best option.
If it's a choice between the heat pump and other central heating systems it's harder to call.
If you've got plenty of wood I would suggest you'd be better off sticking with wood based heating and spending the money on improving insulation, double glazing, etc.
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The Energy Saving Trust will send out an adviser, who will look at first of all reducing energy use, which should be the starting point, then will look at enegy generation. We found them to be very helpful.
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I'd echo the major refurbishment or rebuild point.
Our 1870's property was restored by an imbecile with a fondness for gas boilers. When we embarked on the replacement of the four boilers and the Rayburn we got really keen on heat pumps but we'd have had to rip too much of the house apart to put them in. And the insulation wasn't done to a high standard either.
We saw someone selling low temperature wall mounted radiators intended to be plastered in last year. That would possibly involve less disruption.
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We have an air source heat pump- just to put in a slightly different option. I can't tell you technical details but this is how it worked from my untechie wife point of view. . .
OH spent hours/weeks/months researching online.
We live in a 30's house that is twice as large downstairs as upstairs, half single brick, half cavity walls, barely any insulation. . .
The OH had the cavity walls filled with insulation, and because he couldnt put more insulation in the roof, something to do with sloping ceilings, he took off the ceilings and put insulation board in between the rafters from the underneath, then boarded and replastered. He has so far done 2 bedrooms and the hall upstairs.
SO back to the pump - we couldnt have a ground source pump because I believe option 1 is deep bore holes drilled downwards, which was ridiculously expensive, or option 2 is rows of tubing under the ground and we would have to rip up the whole garden to get the amount of tubing required for our house (incidentally the large school next door (think private in old manor house) has had it done and dug furrows down most of the sides of a hill to get their tubing in).
So, we have the air source pump in the garden which is fairly ugly but is going to be disguised this summer, and produces a fantastic fridge effect on the one side for cooling beer and us in the summer - a big pipe underground into the garage and a large tank and some extra system boxes all in the garage with the fuse boxes. OH also had new radiators put through the house but I think this was for efficiency and not necessary for the heat pump. And I no longer have a tank in the airing cupboard so more storage room! The heat pump heats the water in the tank which has an inner tank and outer tank. The water in the outer tank is used in the radiators and keeps the inner tank warm for the shower.
All together it took a week I think for the installers to put in the pump, tank etc - during which time we had no heating/water. But I now have a fantastically warm house, hot water on tap all the time, a new shower which runs off the tank in the garage (water is apparently pushed round the house under the cold pressure - dont ask me how, which means the shower is more powerful now). Over this very cold winter (our first year with the pump) the old oil boiler comes on when the temp outside drops below minus 3 I think to give it a boost. And I also now have a heater blowing hot air in the kitchen connected to the radiators, which was always freezing before. The kids bedroom is always warm (mine is still to be insulated!) but we still have a log fire in the lounge cos we like it! ;D
Cost wise, it was expensive to put in but has already saved us more in oil than cost in elec this winter so we are money up bill wise. Which means we expect it to pay itself off long before we retire! ;D
I have just read the pertinent points to the OH who is now laughing hysterically at my inability to explain the techie bits and who keeps naming things like buffer vessels (the tank in the garage), compressor and evaporator (the thing in the garden) to make me look really stupid. ;)
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Oh - to add. The insulation was being done anyway, as was changing the radiators. So, it runs through standard radiators with TRVs - the gravity fed hot water cylinder was removed and there was piping and electrics put into the garage. They made no mess in the house at all.
Oh - and we have 4 solar panels on the roof which provide all the summer hot water, so no need for the pump to do it. ;D
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The European Ground Source Heat Pump Association (EGSHPA) website is a business tool dedicated to helping professionals and delivering up to date news and training to further their knowledge and business connections.This website site is designed to make everyone feel part of the community in a totally proactive manner. The European Ground Source Heat Pump Association (EGSHPA) was founded as a non-profit making association and built with the aim of communicating to the industry and consumers the benefits of a new form of renewable energy.
EGSHPA is the ideal bridging point between the latest green energy technologies and the people who benefit from these developments. GSHP is benefial for the enviroment as well as its installation help in saving money, save energy, operating cost.
I would suggest you to install Ground source heat pump as they are electrically
powered systems that tap the stored energy of the greatest solar collector
in existence: the earth.
It benefit the enviroment as well as its installation help in saving money,
save energy, operating cost.
For detail visit:
http://www.egshpa.com/
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I've recently been on a course all about this. I'll start by saying the most enviromentally friendly heating is wood.
Heat pumps are only cheaper than basic electric heating because they produce more heat than the energy you put into the pump. This ratio is the CoP, coefficient of performance. At best 1:4 at worst 1:1.5.
What affects the CoP is the heat source extraction efficiency and the output temperature, plus obviously system running efficiency.
With ground source there is a trend to run radiators at 50 degrees instead of underfloor heating at 30 degrees. The net result is to reduce the CoP from between 1:4 to 1:3 down to 1:2 ,at which point the cost of installation, maintainence and repair (including replacement boreholes) renders the system little better, if at all, than simple electric heating.
Air source heat pumps ice up in the humidity of the UK. They then reverse, taking heat back out of the building to clear the ice. This can happen up to 3 times an hour. So the pump needs to be sized 30% bigger than calculated and sited well away from footpaths or driveways.
You would be amazed at the saleman claims made before the course started. Then the experts and installers started to speak! "And it all went quiet over there".
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We've had an air exchange system installed. Costs about £3500 to install and about £280 a year to run all the heating in the house except water. It's brilliant and works in both old and new houses when temperatures go as low as minus 20 degrees C.
This is their website: www.eheatgroup.com (http://www.eheatgroup.com)
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The heat pump idea goes back quite a long way. When the Royal Festival Hall was built in the early 1950's, a redundant merlin engine from a Spitfire or Lancaster bomber was installed to provide the heating. It used its supercharger to compress gas which then provided heat all around the building. The gas then expanded cooling it. Water from the Thames then reheated the gas. It achieve a COP of 4 which was pretty good for the time and the technology used.
There are a couple of lessons here for anyone considering a heat pump system. The merlin engine required a lot of maintenance and the idea was dropped after a few years. Modern heat pumps are very similar to a big fridge compressor. They should run happily for 10 years but will need replacing and are not cheap.
The source of heat is important. Soil is probably better than air but if you have any local heat source like a stream, large pond or waste heat from a factory or brewery, it will help the COP a lot. A figure of 6 or more is then possible.
Also, you could use a small engine to drive the compressor. Something like a small diesel engine from a tractor. You would only need a few horsepower continuously as 1hp=0.75Kw. Multiply this by the COP to get the heat output. This means heating oil could be used as fuel rather than electricity. Waste heat from the engine can then be collected to heat the house as well as the heat from the compressor so that the exhaust gas and the engine cooling system all contribute.
The downside of this idea is the noise and maintenance costs. But it is worth considering.
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We have it, we love it. We were advised two things which we did and would advise anyone to do the same.... Don't mix radiators with underfloor heating, it's less effective apparently. The second thing is to over spec your tanks, again it makes the system more efficient. We don't have a back up system, at the moment (we have HelpXers staying) there are 7 of us living here and we never run out of hot water. :thumbsup:
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I've found this topic thoroughly interesting especially the heat exchange air pumps from eheatgroup.com .
We are spending around two & 1/2 tanks worth of oil for heating & hot water a year (in excess of £2.5 k perhaps ) despite having a complete new latest bees knees heating system and full wall & roof thermal insulation. . Seeing as we have a Wi-Fi room stat we can drop that to zero and still have plenty of hot water from the balanced flue oil combi boiler . It sounds like these heat systems could be good for us
Can any one tell me ........ does the warm air in help dry out damp musty places. I ask because :-
We got flooded out 4 yrs. ago due to " Mr Nearly" who we purchased the property from playing at being plumber , builder & electrician when the hidden central heating pipes leaked and flooded the whole bungalow floor slab . It took over a year to try and get it dried out and repaired whilst we lived elsewhere .
This last 18 months we've noticed we get a musty smell if the bedrooms doors are closed. We don't usually heat them unless it's a heavy frost forecast though we do have trickle vents in all windows for which the smallest air flap is always open to keep an air flow going as well as we opening most windows for fifteen minutes to half an hour or so each day to sweeten the home up.
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Thanks for all the useful advice here, we are looking into replacing the oil system here in our very old house with a GSHP system. We've had one quote so far but it was a commercial one to include heating the chicken shed. If we were chicken farming it would represent a great saving, but as we're not it would be far too expensive so I'll be getting some domestic quotes shortly.
The guy we saw said that several deep holes would be cheaper to install than the equivalent shallow hole, which surprised me but perhaps that was because of the scale proposed. But he never mentioned streams or ponds so I was really interested in the comments on here about that. We have 3 streams and a pond on our land, although only one stream is near the house. How do you install a GSHP to make use of the advantage of a stream?
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I can't offer advice as such because we bought the house with GSHP already installed, and I haven't calculated the bills yet - there's a very odd situation with the eclectic it's company - but our estimated monthly payment is not much more than our total gas & electric payments at our old house, and now we have constants hot water (ok, a big storage tank) and underfloor heating around the whole ground floor and two radiators upstairs.
It seems to me that GSHPs aren't fantastically cheap to run but you do get a cosier house - assuming it's well insulated as mentioned here before - and there are options to make it more efficient and even off-grid safe.
We've been told by a couple of professionals that we should consider a solar hot water panel or two that would be fitted in front of the heating system to pre-warm the water and therefore reducing the energy required to heat the water. Obviously this only works during the day, and better on sunny days than dull ones, but it works out a much cheaper and more efficient option than solar PV. We'll probably get solar PV too, but at the same time as the solar hot water to save on installation costs.
One downside to GSHP powered undefloor heating is that if you don't have room thermostats installed you won't be able to control the house temperature very quickly - our system takes at least 12 hours to adjust because of course it is dependent on the loop and heating process. We tend to leave it quite low all the time and it balances out. During the summer I've even turned it so low that the floors are almost cold, and in the winter we crank it up but support it with the log burner in the living room.
After a year with this system I don't think I would pay my own money to instal it, but as it was included in the house when we bought it I'm happy to have it.
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We installed a GSHP about 18 months ago and have monitored performance and costs.
Our house dates back to 16thC. We did upgrade insulation where possible but that was limited because of clay lump walls. All radiators had to be replaced, and we also opted to put in some under floor heating whilst carrying out other works in some of the ground floor areas.
The first full year of operation cost us an additional £490 in electricity compared to our electricity consumption the previous year. Consumption over the past last six months is very much in line with the first six months so I would expect our 2nd full year additional electricity cost to be in-line with year 1.
Previously, we were using an oil fired boiler and spending around £2000pa on heating oil.
The past two winters have been relatively mild so accurate comparisons with earlier years are almost difficult to achieve.
A further big plus is that the house is much warmer. The old oil boiler used to be on about 8 hours a day so we had significant parts of the day without heating, whereas the GSHP system runs 24/7 and the house is cosy all of the time
So: a warmer house, a 4:1 energy efficiency resulting in a 75% reduction in energy spending
What did it cost ?: around £30,000, excluding the under floor heating which was part of a larger project
What about the RHI payments ?: We get a quarterly RHI payment which, over the 7 year period that it will be paid, will amount to around £30,000. So we get our money back (without interest) and will also save around £1500 a year on oil
Conclusion: It's a big outlay. £30K would buy a lot of oil. Without the RHI it would never stack up. It works for us, and we are very happy with the performance
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Happy Harry - where are you based in UK? Are you still happy with your system?