6.3 Brine circuit

The maximum recommended length of one loop of the collector is 600 m. If a longer brine circuit must be installed, it should be divided into several loops and connected in parallel. The connection should be made in such a way that it is possible to balance the flows in the loops. The collector pipe network should steadily rise towards the heat pump to prevent air pockets. If this is not possible, vent valves should be installed at the high points. Before installing the heat pump, rinse the collector pipe network to remove any impurities that may remain after installation.
  • Insulate all of the collector pipes in the building using closed-cell insulation to prevent condensation.
  • Only use connecting components designed for cold conditions in the collector.
  • Use rubber-insulated brackets for pipes.
  • Install shut-off valves in pipe connections as close to the heat pump as possible.
  • Enter the type of collecting liquid and the freezing point in the installation record.
  • Make sure that the top of the heat pump and the electrical equipment are entirely free of water during operation.
  • Only use a diaphragm expansion tank in the collector. The use of a flat expansion tank is not recommended.
  • Check the pre-charge pressure of the diaphragm expansion tank in accordance with the plan before pressurising the system. Check the pre-charge pressure when the circuit is open.
  • Connect the collector valve group with the related expansion tanks as shown in the figure. The arrow on the poppet seat indicates the flow direction.
  • The collector must be pressure-tested with 3 bars of pressure and the test pressure must be sustained for at least 30 minutes.
Figure 1. Connecting the brine circuit to the heat pump
Installing the collector onto several loops
If you are using several collector loops, every circuit must have shut-off and control valves. Follow the valve manufacturer’s instructions when you install control valves. The valve must be installed in such a way that it is easy to adjust and inspect, and it does not freeze. Vent the circuits one at a time and regulate the flow rate in relation to the lengths of the circuits. Try to use collection loops of equal length.
  • A: Collector inbound to the heat pump
  • B: Collector outbound from the heat pump
  • C: Shut-off and control valve
Passive cooling

Passive cooling functions best when heat collection is arranged using a bored well. During the summer, loops installed in the soil or in lakes may be at such a high temperature that the required cooling power cannot be obtained. Air within the collector should be allowed to freely rise to the expansion tank. Venting should always take place at the highest point in the collector. If it is necessary to connect the cooling radiator to the highest point in the circuit, venting should take place via the radiator.

Refrigeration can be controlled or regulated using a cooling accessory available for the heat pump. Building automation or ventilation machines can also control the heat pump’s internal source pump. See the electrical diagrams for instructions.

Parent topic: Installing the pipes