There are a wide range of geothermal system on the market today. There are also alot of different ways in which geothermal heat pumps are used to heat a project. Here are the most common ways geothermal systems are configured
1) The most common one in this country is using a geothermal heat pump with a buffer tank. Basically here with this system, the heat pump’s sole duty is to keep the water in the buffer tank to a set temperature. Usually between 30 and 40 degrees. From this the underfloor heating has a “store” on which it can obtain its hot water for heating the house.
The main advantages is that you have a controlled system. The buffer tank is protecting the heat pump by acting as a heat dump every time the heat pump comes on. From this , you are protecting the life span of the compressor i:e, the heat pump will only come on when the buffer tank is not at the designated temperature and because it has to heat a big volume of water, it will take the heat pump some time to do this.
The main disadvantages are
1) Fixed COP (Coefficient of Performance). Even on a mild day outside, the buffer tanks water temperature will still be at the same temperature. This is not required because on a mild day, there is less heat loss from the house, so your underfloor heating does not need the same water temperature in its pipes. Essentially you are paying for too much electricity.
2) The cost of putting in 2 cylinders is a disadvantage (Buffer tank & Domestic hot water cylinder).
3) Space required. You need a big utility room to insert all these items. It is pointless putting a heat pump in a garage off the house because you are going to loose some heat in transit. And because single phase heat pumps do not give big outputs, you want to get everything out of it that you possibly can.
In my next post, I will discuss the second way Heat Pumps are configured
