Differences in Geothermal Systems Part II

Geothermal heat pumps (especially from sweeden) now also have weather compensation units built into the product. This means that the heat pump compensates or adapts to the outside air temperature and from this gains efficiency especially in autumn and spring. Other heat pumps which are used with a buffer tank and therefore have a fixed cop (coefficient of performance) pump water into the underfloor heating which is consistently at the same temperature. With heat pumps with weather compensation, you may not need the same water temperature in your underfloor heating on a mild day. The outside thermostat or else the pipe stat (usually located on the return pipe to the heat pump) picks up the temperature and from this knows what temperature the water in the underfloor heating should be in order to achieve the desired temperature in the house.

The advantage of a system like this is that one does not need a buffer tank. The heat pump still needs a heat dump and this is done by permanently leaving 1 or 2 zones open in the underfloor heating system. So when any of the other zones are calling for heat through the thermostat, the other "open" zones will also be heated. Open zones are usually hall, bathrooms, etc (small zones where you dont mind it being consistently heated)

A disadvantage of one of these types of systm is that since the system is set up to adapt to the outside air temperature, your house will never be piping hot. The system is set up to always overcome the heat loss from the house but only just. In a fixed cop system, having a fixed water temperature going into your underfloor heating will some days give you a very warm house and others not so warm. A weather compensated system will give you always a controlled system so even on mild days, your house wont feel that warm and the same in cold days. This for Irish projects can sometimes be a disadvantage as we are used to having piping hot houses in the winter

In my next post, I will discuss the third way Heat Pumps are configured.

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