COLD LIQUID
REFRIGERANT
3
4
COOL GAS
AMBIENT
AIR
1
2
COMPRESSOR
EVAPORATOR
HIGH PRESSURE SIDE
CONDENSED
REFRIGERANT
WATER IN
HOT GAS
WATER OUT
HEAT
EXCHANGER
LOW PRESSURE SIDE
EXPANSION
VALVE
COLD LIQUID
REFRIGERANT
The
CALOREX
Heat Pump provides thermodynamic heating by means
of a vapour compression cycle, (similar to that employed in a conventional
refrigerator), in addition to operating as an active solar collector.
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.
Naturally this ratio will vary according to the temperature of the ambient air.
NOTE THAT WHEN A HEAT PUMP IS CHILLING THIS CYCLE IS REVERSED
2. The
COMPRESSOR
where it is
compressed and upgraded to a much
higher temperature. The hot vapour
now enters -
4. The
EXPANSION DEVICE
and from there,
now at normal pressure, it is returned to the
evaporator and the cycle starts again.
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 -
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 -
COEFFICIENT OF PERFORMANCE
THE HEAT PUMP CYCLE
5
SD331851 ISSUE 28
