About Your Heat Pump; Principles Of Function - Danfoss DHP-AL User Manual

2

About your heat pump

2 .1

Principles of function

A heat pump utilises the free energy found in a natural heat source, such as rock, ground,
or air. The heat pump can be compared to a reversed refrigerator. In a refrigerator, heat is
transferred from the inside of the refrigerator to the outside. In a heat pump the heat that
is stored in a heat source is transferred to the inside of the house. The heat pump uses the
energy in the heat source and gives back two to three times more heat energy than what it
uses in electrical energy. The heat pump is, therefore, a very environmentally friendly and
economical way of heating a house.
In order for the heat pump to be able to retrieve heating energy from the heat source and
transfer it to the heating system of the house, three separate fluid circuits are required.
The circuit that retrieves the heating energy from the heat source is called the brine circuit
and it maintains a low outgoing temperature to be heated by the heat source.
The next circuit is called the refrigerant circuit and is a closed circuit which takes the retrieves
heating energy and transfers it to the last circuit, the heat transfer fluid circuit.
The heat transfer fluid circuit holds the fluid that circulates in the heating system of the
house and in the heat pump's water heater.
The figure below shows how the different circuits work together in the transfer of heating energy.
Heating system and
Expansion valve/
pressure drop
Enclosed
refrigerant
Brine
1 A fluid (brine) filled hose is lowered into a lake, buried in the ground or lowered into bed-
rock. The brine obtains energy from the heat source by the fluid temperature in the hose
being heated a few degrees by the surrounding heat source. The fluid filled hose is also
known as a collector.
water heater
Condenser
Compressor/
pressure increasing
Evaporator
Heat source
Figure 1: Function principles of a heat pump .
Heat transfer fluid circuit – is the circuit that contains the water that
transports the heat/energy to the heating system and the water heater.
Refrigerant circuit – is the circuit that contains a chlorine and freon free
refrigerant which, inside the heat pump, transfers the energy retrieved
from the brine circuit through evaporation, compression and condensa-
tion, and supplies it to the heat transfer fluid circuit.
Brine circuit – is the circuit that contains an antifreeze water based mix
that obtains and transports energy from the heat source to the heat pump.
This circuit is also known as the collector.
VUBMF102
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