The Heat Pump Cycle - Dantherm calorex AW834 Owners & Installation Manual

THE HEAT PUMP CYCLE

The CALOREX Heat Pump provides thermodynamic heating by means
of a vapour compression cycle, (similar to that employed in a conventional
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 water
to be heated. The heat is given up to the cooler 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 -
NOTE THAT WHEN A HEAT PUMP IS CHILLING THIS CYCLE IS REVERSED
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 water is said to
have a C.O.P. of 5:1.
SD331851 ISSUE 28
COMPRESSOR
HOT GAS
3
HEAT
EXCHANGER
CONDENSED
REFRIGERANT
EXPANSION
VALVE
4
HIGH PRESSURE SIDE
refrigerator), in addition to operating as an active solar collector.
1. The EVAPORATOR collects the heat from the outside ambient
air, pre-heated by the sun. High volumes of outside air are drawn
through the Calorex unit by the fan and 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 -
2
COOL GAS
1
EVAPORATOR
COLD LIQUID
COLD LIQUID
REFRIGERANT
REFRIGERANT
LOW PRESSURE SIDE
4. The EXPANSION DEVICE and from there,
now at normal pressure, it is returned to the
evaporator and the cycle starts again.
Naturally this ratio will vary according to the temperature of the ambient air.
AMBIENT
AIR
5