The Heat Pump Cycle - Calorex Pro-Pac Series Owners & Installation Manual

THE HEAT PUMP CYCLE

The Calorex Swimming pool heat pump provides thermodynamic
heating by means of a vapour compression cycle, (similar to that
2. THE COMPRESSOR where it is compressed and
upgraded to a much higher temperature. The hot vapour
now enters –
WATER
OUT
WATER
IN
3. THE CONDENSER where it is surrounded by the pool water.
the heat is given up to the cooler pool water and the now cold
refrigerant returns to its former liquid state but still under high
pressure from the compressor.
This pressure is released by passing the liquid through –
Coefficient of Performance
The efficiency of a Heat Pump is usually called its 'Coefficient of
Performance' – (C.O.P.) which is simply a ratio of heat output to
energy input, both being expressed in kW. Thus a Heat Pump
absorbing 1 kW of electricity, collecting 4 kW of energy from the air,
and delivering 5 kW of heat to the pool water is said to have a C.O.P.
of 5:1.
Naturally, this ratio will vary according to the temperature of the water
and the ambient air.
SD566252 ISSUE 51
employed in a conventional refrigerator), in addition to acting as an
active solar collector.
1. THE EVAPORATOR collects the heat from the outside
ambient air, pre-heated by the sun. In the Calorex swimming
pool heat pumps, high volumes of outside air are drawn into
the unit by the fan expelled through the evaporator fins. The
evaporator has liquid refrigerant passing through it Which is at a
considerably lower temperature than the ambient air. Therefore
the air gives up its heat to the refrigerant which then vaporizes.
This preheated vapour now travels to –
COMPRESSOR
HOT GAS
HEAT EVAPORATOR
EXCHANGER
CONDENSED
REFRIGERANT
EXPANSION
VALVE
HIGH PRESSURE SIDE
normal pressure, it is returned to the evaporator and the
cycle starts again.
Note that during the cooling cycle this process is reversed.
COOL GAS
COLD LIQUID
REFRIGERANT
LOW PRESSURE SIDE
4. THE EXPANSION DEVICE and from there, now at
AMBIENT AIR
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