Heat Pump Technology

Discussion in 'OT (OFF Topic) Forums' started by altreed, Aug 31, 2008.

  1. altreed

    altreed Hardcore MB Enthusiast

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    I have searched the forum and came across a post that commented on Heat pumps, maybe it deserved to be a separate post/topic.... So here it is.... :rolleyes:

    I am looking to replace our kitchen and move/ditch a 20-30 year old Oil boiler. Inititally I thought of just replacing it with a newer one and place it in the loft. A kitchen fitter suggested that I may not be able to do that for legislation (or summat) so I started to look at the alternatives. Hence starting this post....

    Has anyone actually got experience with ground source or air source heat pumps, could you share your experience.

    We have a reasonable sized garden and could dig a trench rather than a bore hole. I am thinking of maybe extending my drive, such that when the work is done we could cut the trench and economise on hiring diggers etc. Would it be possible/adviseable to put the ground source under the drive/car port??

    Any experience or advice appreciated
    Dave
     
  2. Ade B

    Ade B Hardcore MB Enthusiast

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    If you trawl about there are a load of websites with a lot of info. The Daikin one seems down at the moment...

    Heat pumps are not the panacea to energy consumption they intially appear to be, we are specifying air source heat pumps for a new build development (a long way off starting on site) and are hoping to install an air source heat pump to heat a swimming pool in a project in London. We are working with a mechanical services consultant on both projects which basically means I don't get involved with the technicall nitty gritty:eek::).

    It seems to me (as a relatively technologically competent) architect that there are a fair few grey areas with the technology and heat pumps - basically they are very efficient in certain circumstances (with underfloor heating) but they are not an a direct alternative to a standard boiler which runs water at a much higher temp to radiators.

    Not sure why you can't put the boiler in the loft, provided it is ventilated and can be accessed and the flue is correctly positioned it should be ok..

    Have a look here for more info on boiler positioning.

    Ade
     
  3. V8mate

    V8mate Hardcore MB Enthusiast

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    Ground source heat pumps: it's all about how far you can afford to drill. A lot of domestic types only run to about 30 feet deep - with such a system you're looking at getting maybe 12 degrees C added to cold water - so it's not a hot water solution, it's just reducing the amount of heating you need to addto the water for domestic use; whether that be underfloor (or other) heating or direct to hot water taps.

    On a development I'm managing in London, we are having to pile to 90 metres(!) to gain a meaningful uplift in water temperature from such a renewable energy source.
     
  4. gbjeppm

    gbjeppm Hardcore MB Enthusiast

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    My parents have an Air Souce heat pump heating their swimming pool, which seems to work fine, especially when the ambient temperature is above 20 degrees.

    So for the job it does, heating water in a pool for use in the summer months only it seems to be fine. Heating anything that is needed in the winter months, I think would be a stretch too far.

    I do though know there is a difference between swimming pool ones, and domestic ones.

    For info they have one of these

    http://www.calorex.com/Product_Range.htm
     
  5. OP
    OP
    altreed

    altreed Hardcore MB Enthusiast

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    Thanks guys,

    I have had a look through the Calorex website and the info suggests that the system can be a replacement for a traditional boiler, although it also suggests that it can be used in addition to the boiler (used as a top up).

    I am hoping that someone knows someone that has taken this step, we are a month or two away from doing anything, so I have some time to research it before we bite the bullet and employ anyone to start any works. :rolleyes:
     
  6. joe

    joe Hardcore MB Enthusiast

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    as you already know the amount of energy/heat you will extract from a heat pump will never jusify your initial investment (domestic type)
    The cheaper option may be a simple solar panel to raise the temp of your water supply to DHW system.
    Of course I do not know your budget or desire to save the planet.

    Installing a Boiler in a Loft or roof space is not a problem (adhere to relevant flue and ventillation regs)
    Go for an A rated appliance...update your Insulation
    Best of Luck
    Joe
     
  7. OP
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    altreed

    altreed Hardcore MB Enthusiast

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    Thanks Joe,

    I need a new heating system as the old one is in the wrong place and very inefficient - 20-30 years old. I do not really concern myself on saving the planet as I have 2x large cc cars (no hybrid Prius in sight or even on the radar). However, a more efficient new technology is attractive, hence considering the 'green' options to make wise 'long term' investments. I would never see the money back on a new oil boiler either :p We do plan on staying in this property for the next 20-30 years and expect to be carried out of it in a box! :rolleyes:

    I know that I need to update the insulation as the existing stuff is micro thin. I was considering using the sheeps wool stuff, saw it on 'Grand Desgins'. Supposed to be the business for insulation, no idea where you can get it as yet. Not yet on the radar, so I am not worrying about that atm.
     
  8. joe

    joe Hardcore MB Enthusiast

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    Dave, I have only just realised you are replacing an Oil Fired Boiler (I never read your post carefully enough)
    It is more complicated to install in roof spaces you need to look at oftec, they are the Corgi of the Oil Combustion Industry.
    I understand your point in looking at alternative energy sources.:)
    Fuel costs are not likely to drop.

    Joe
     
    Last edited: Aug 31, 2008
  9. Ade B

    Ade B Hardcore MB Enthusiast

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    why don't you employ a mechanical services engineer to design your system - the fee won't be much and it will mean the system will be tailored to suit your requirements.

    AFAIK, if you want to run the heating just from a heat pump, you need to look at underfloor heating as the hot water temperature produced is much lower than conventional radiators.

    Ade
     
  10. Piff

    Piff Hardcore MB Enthusiast

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    I'm currently investigating along similar lines - I have a house to build soon in an area with no gas.
    I heard recently that ground source heat pumps don't extract much more heat than the electricity consumption of the system - I don't know if this is true or not.
    I my situation there isn't a huge amount of land to work with anyway.
    I've been looking at electric combi boilers www.thermaflowheating.co.uk as for a new build the installation costs seem similar to oil boiler + tank etc.
    However this system is designed in Scotland where they have access to an electric tarrif with 18 hours off peak. The best I can find around here is "economy 10" and this does not seem to be widely supported.
    I've yet to get to the bottom of running cost comparisons to make my final decision.
    Does any one else have experience of electric systems to compare to oil?
     
  11. Rory

    Rory MB Club Veteran

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    If you're building from scratch, have you looked at mechanical heat recovery?

    Was chatting to a colleague from Finland where such systems are mandatory and he was amazed they're not fitted here. There are suggestions that the latest systems can recover 90% of the heat, and I've often wondered whether it might be possible to use an air heat pump on the extracted air to multiply the heat gain (but I might be talking rubbish!).

    I've often thought about such systems as my wife isn't happy unless there's a gale of fresh air blowing through the house and heating it is a losing battle. :crazy:
     
  12. 124fan

    124fan Hardcore MB Enthusiast

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  13. crockers

    crockers MB Club Veteran

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  14. Dieselman

    Dieselman Banned

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    Surely that depends on water flow, heat loss and initial temperature. A 12c uplift will definately heat a cylinder of water as it will keep recirculating the warmed water from the cylinder, which will keep warming gradually.
     
  15. Dieselman

    Dieselman Banned

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    No good if you don't have gas to power it. It's just a small scale CHP unit.
     
  16. Dieselman

    Dieselman Banned

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    What for, DHW or space heating? That is just a woodburner with a backboiler, a hopper fed pellet burning boiler would be a neater solution.
     
  17. Dieselman

    Dieselman Banned

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    Without a doubt insulation is the way forward, then you need much less energy input.
    Sheepswool, is nice to touch (roll in :eek: ) but isn't as efficient as phenolic board, but is more enviro friendly in manufacture.
    It would be worth having an air pressure test performed to find where all the air is leaking out from so as to target the leaks and improve efficiency.

    Start with the insulation and underfloor heating. These measures will reduce your energy requirement significantly, then look at options for heating the space and water.

    You will need a considerable land space for a ground source heat-pump to work from solar but you could always have a bore hole drilled.
    IIRC ground source pumps are classed as being 400% efficient and air source as 300% efficient.
    They cost the same to run as a gas boiler due to electricity costs being higher.

    I would consider installing solar water heating, underfloor heating and use a ground source heat pump as backup. If you really want to go the whole hog install a whole house heat recovery system with solar air heating on the input side as well.
     
  18. Piff

    Piff Hardcore MB Enthusiast

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    I have thought of this, and discussed it with someone else who has investigated. He said that these systems only work if the house is well sealed as in scandinavian countries (and Canada). As soon as you open a window the benefits are lost. I think we (the british public) don't yet have the right attitude for these systems!
     
  19. Rory

    Rory MB Club Veteran

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    That's absolutely true - user training could be difficult!

    There are EU plans to have us living in sealed boxes - some info here:
    http://www.passivhaus.org.uk/
    - I gather the UK is thinking about implementing these standards by 2016.
     
  20. Dieselman

    Dieselman Banned

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    I doubt that, it's simple. Don't open any windows.

    There is a school of thought says that these units don't recover much more energy that they use to pump the air round, although they do ensure a well aired house.
     

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