There’s a very interesting article at http://carbonlimited.org/2009/08/11/heat-pumps-emit-more-carbon-than-gas-boilers-so-why-will-they-get-the-renewable-heat-incentive/. Basically it says that because electricity from the grid is partly generated by fossil fuel power stations and that getting this electricity to your house is inefficient, the CO2 output is actually greater if you run a GSHP system than if you run a gas boiler. The author then questions why there should be government incentives to install these systems.
This might be true, but if you power your heat pump using solar panels at your property (or buy your electricity from a green-energy-only supplier) then surely this isn’t true in that instance.
Furthermore, electricity has to be the fuel of the future (as fossil fuels run out, energy has to be sourced more and more from renewable facilities which means electricity) so it must be a good thing that people are installing these systems now.
August 14, 2010 at 1:01 am |
We install solar powered heat pumps and a/c, but air source instead of geothermal. We can power enitire units now via solar panels, which is great for air conditioning savings. The issue we have is that most heating is done at night, when the sun is down and can’t power the unit.
For us, battery storage to power the unit at night is not possible because of the high current draw, but this probably isn’t true for groundsource.
August 18, 2010 at 12:40 pm |
The COP or the coefficient of performance (measure of energy in over energy out) of a heat pump system is dependent on many factors. The best document to use to gain an understanding is the VDI guidelines 4640 which is a German standard but written in due language English. The basic factors which will affect a design will be the soil conditions, the flow temperature of the heating circuit and the heat pump. With a heat pump connected to standard radiators you would be better off using a gas boiler. A heat pump working with special underfloor heating with a flow temp of 35 degrees COP will be in the region of 4-5. If you regenerate the ground source with summer solar or cooling COP can be as high as 10.