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–EIMWC00408-16EN - 23/60
These condensers, with partial heat recovery tubes, have crowns with special couplings by which they can be connected
to the hot water pipes. When partial recovery is activated, condenser performance is improved since the condenser
temperature is lowered further in as much as the surface dedicated to heat discharge is greater.
After passing through the cooling tubes, the gas starts to condense in the central part of the condenser.
The condensed fluid at saturation temperature passes through the subcooling section where it looses even more heat,
increasing the efficiency of the cycle. The subcooled fluid flows through the high-efficiency filter dryer and then reaches
the expansion element (expansion valve) through which a fall in pressure starts off the expansion process resulting in the
vaporisation of part of the refrigerant liquid.
The result at this point is a low-pressure and low-temperature liquid-gas mixture entering the evaporator, where it takes
the heat required for vaporisation.
When the refrigerant liquid-vapour is uniformly distributed in the direct expansion evaporator tubes, heat is exchanged
with the cooling water, thus reducing the temperature until complete evaporation, followed by superheating.
Once it has reached the superheated-vapour state, the refrigerant leaves the evaporator and is once again taken into the
compressor to repeat the cycle.
Controlling the partial recovery circuit and installation recommendations
The partial heat recovery system is not managed and/or controlled by the machine. The installer should follow the
suggestions below for best system performance and reliability:
1)
Install a mechanical filter on the heat exchanger inlet pipe.
2)
Install shut-off valves to isolate the heat exchanger from the water system during periods of inactivity or
system maintenance.
3)
Install a drain valve that allows the heat exchanger to be emptied in the even that air temperature is
expected to fall below 0°C during periods of inactivity of the machine.
4)
Install flexible anti-vibration joints on the heat recovery water inlet and outlet piping, so that
transmission of vibrations, and therefore of noise, to the water system is kept as low as possible.
5)
Do not load exchanger joints with the weight of the heat recovery piping. The water joints of the
exchangers are not designed to support the weight of the piping.
6)
Should heat recovery water temperature be lower than ambient temperature, it is advised to switch off
the heat recovery water pump 3 minutes after having switched off the last compressor.
