What is an open loop borehole non-tidal collector?
Open loop borehole ground source heat pump installations transfer water from one location to another, extracting heat energy in the process.
As per all open loop system collectors, no anti-freeze fluid is featured in non-tidal water open loop borehole installations. Water from the non-tidal water source is abstracted and filtered through the heat pump via a borehole. This water is then discharged either back to another section of the water source via a second borehole or open loop straight pipe.
Consideration needs to be taken with regards to corrosion issues, filtration, extraction and possible freezing within the heat exchanger. It is also important to consider the electrical energy required to pump the water to the heat pump.
Water collectors have a number of advantages:
- The heat transfer rate from water is higher than that in the ground;
- The water is in close contact with all of the pipe at all times enhancing it’s efficiency;
- The flow/circulation of water provides constant energy replacement;
- The use of a water source removes the need for digging or drilling, reducing the cost and duration of the installation;
- The return temperature to the heat pump is generally 5-6°C higher than ground collectors, increasing the efficiency of the heat pump.
Things to consider
If you are considering an open loop borehole for your ground source heat pump system, there are a number of points which need to be taken into consideration:
- Seek relevant permissions from the Environmental Agency
- Consider the design of any scheme to ensure its longevity and efficient performance