Open Loop Ground Source Heating Systems
Open loop systems use ground or surface water pumped directly through
the heat pump's heat exchanger. The temperature of ground water will be
about 7
-10 deg in the UK. This will provide an increase in
efficiency of about 20% over closed loop systems. For the reliable
operation of an open loop system a number of factors need to be
considered. The open loop system will generally use fresh water. This
will freeze at 0° C so care must be taken to ensure that
freezing of the heat exchanger does not occur. Freeze
protection systems are used.
For this type of system a reliable supply of water is required. The
flow rate should be
high enough to provide sufficient heat when the system is started from
cold. The heat exchanger is specified to easily provide
equalised refrigerant and water exit temperatures. Undersized
heat exchangers are prone to freezing due to lower refrigerant
temperatures.
The heat exchanger is resistant to the composition of the water. It is
designed to allow for some degradation of
the thermal conductivity over time due to the
building of deposits on the exchanger surface.
Ponds, streams and rivers can be used as a source of water. Water
should be taken from the bottom of a pond where the temperature is
higher in winter.
Geothermique can provide a bespoke design service for open loop
systems. We are able to provide off the shelf or one off individually
designed systems using high quality stainless
steel brazed heat exchangers. Please contact us to discuss
your requirements