PowerSwitch

Mary76 · Banned Joined: 04 Jan 2018 Posts: 1

Tax credits have fueled the implementation of this technology. The average cost seems high at 20,000; but with 30% tax credits; and the cost of a replacement HVAC pending..... Your ROI can be lower than you think

ground source heat pump advert deleted.

kenneal - lagger · Posted: Thu Jan 04, 2018 3:59 am Post subject:

This system is not what we would call geothermal in the UK. It would be called a ground source heat pump system here. It requires a heat pump to raise the temperatures to something useful.

We would call a system geothermal when the temperature of the liquid arising from the ground didn't need any treatment to raise it to a useful temperature. Hot rocks such as granite, with its decaying radioactivity, are often used as such a source in the UK while volcanic structures are often used elsewhere in the world, Iceland especially.
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BritDownUnder · Posted: Thu Jan 04, 2018 12:36 pm Post subject:

It is generally and quite possibly incorrectly called geothermal here in Australia.

Setting aside the attempt at a free advert I think the technology is worth investigating. I remember that a poster who no longer is active on this site was very severely criticised for getting this technology.

From what I have been able to ascertain this technology is quite new to Australia and is therefore expensive. Myself I would not have the land area in my back garden to lay the shallow piping so i would have to go for the boreholes which I understand would go down about 80 metres.

From looking at the Waterfurnace website specs heating would be the best use for this technology as in my area the ground temperature is 22 deg C which would give a heating COP of around 6, meaning I would get 6kW of heat (or is it 5? I forget) for every 1kW invested. Cooling would be a lot less efficient with a COP around 4. I estimate where I live I need to heat and cool approximately equally obviously at different times of the year.

Of course the capital costs are are quite severe with a $20,000 trip to the cleaners being involved. You get a lot of firewood or air source heat pumps for that price and even insulate the place very well. In short getting this system is not on my radar at the moment.
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