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2.2. Evaporator
The evaporator is a plate heat exchanger which transfers heat from the cold water to the
refrigerant. In order for the heat transfer to take place, the refrigerant in the evaporator has a
lower temperature than the cold water and when it absorbs heat it changes its physical state from
liquid to gaseous.
If the cold water is contaminated, deposits can form on the transfer surfaces of the evaporator.
These impair the heat transfer to the refrigerant and reduce the refrigerating capacity of the
machine. For this reason, always ensure the specified water quality and do not use any other
additives than those specified.
2.3. Condenser
The condenser is a microchannel heat exchanger which transfers heat from the refrigerant to the
ambient air. In order for the heat transfer to take place, the refrigerant in the condenser has a
higher temperature than the ambient air drawn in and when it gives off heat its physical state
changes from gaseous to liquid.
Contaminated cooling air can cause deposits to form on the surface of the condenser over time.
This impairs heat transfer to the refrigerant which restricts the operating limit of the machine and
reduces the machine's refrigerating capacity. Please refer to Chapter 9: Cleaning for a description
of how to clean the condenser. If you operate your chiller in an environment containing dust or oil
vapour, use the optionally available air filter mat (see 3.19 Air filter mat).
In case that there already is an existing house water system and the warm condensing air has to
be avoided, the chiller can also be specified with a water cooled condenser (see 3.3 Version with
water cooled condenser)
2.4. Expansion valve
The expansion valve controls the admission of liquid refrigerant to the evaporator and at the
same time restricts the pressure of the refrigerant before it enters the evaporator. With this
restriction the refrigerant cools to the evaporation temperature.
The expansion valve used in your machine is controlled electronically. The electronic control
ensures that the evaporator is always optimally supplied with refrigerant. This improves the COP
(Coefficient of Performance) and reduces pressure fluctuations in the refrigeration circuit.
2.5. Refrigerant
The refrigerant R410A circulates in the refrigeration circuit. It conveys heat from the evaporator to
the condenser and at the same time continuously changes its physical state.
R410A is a fluorinated greenhouse gas consisting of the zeotropic mixture of 50% R32 and 50%
R125 with virtually negligible temperature glide. R410A has a very high volumetric refrigerating
capacity and has no ozone depletion potential (ODP=0). A corresponding safety data sheet can be
obtained from our KKT chillers Service Team (see Table 1: Contact details).
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