Johnson Controls SABROE HeatPAC, Operating Manual

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Operating manual - HeatPAC with reciprocating compressor
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009332 en 2021.07
Design and function
3.2 Main components
3.2.1 Compressor
The compressor is a Johnson Controls Denmark standard compressor, complete with stop valves, mo-
tor, oil separator etc. For further information, see compressor operating manual.
3.2.2 Control system
HeatPAC is delivered with UniSAB III monitoring, safety and capacity regulating system.
The control system is described in the UniSAB III manual.
UniSAB III setting list for each specific order is enclosed with the manual.
If the actual operating conditions are different from the design conditions the settings must be checked.
VSD settings are stated in the wiring diagrams.
Note: Changes in factory settings must only be carried out by competent personnel.
3.2.3 Evaporator
The evaporator is a fully welded plate heat exchanger where plates are welded together into cassettes.
R717 evaporates between the two welded plates which make up the cassettes and water/brine is cooled
in the channels inside the cassettes. The R717 droplets are separated from the vapour in the separator
room above the plates.
The evaporator has one or two sets of brine connections depending on size and operating conditions.
A sight glass is mounted at the end cover.
Note: The liquid level must never be visible in the inspection glass. See subsection 6.3 R717 charge
and the P&I diagram for correct charge.
3.2.4 Cascade evaporator
The evaporator can also function as a cascade cooler. In this case discharge gas from a separate circuit
(refrigeration plant) is cooled and condensed inside the cassettes.
The upper connection (DN100) is the discharge gas inlet and the bottom connection (DN100) is the
liquid outlet. This design minimises the refrigerant charge and eliminates problems when mixing different
oil types.
There is very little volume on the condensing side which makes the cascade evaporator very sensitive
to non-condensable gasses.
A by-pass with a 2 mm orifice must therefore be installed between the liquid outlet connection and the
low pressure side of the refrigerant plant. Alternatively, an automatic purge system for non-condensable
gasses can be installed.
As an additional feature the cascade evaporator can be equipped with a high pressure float valve at the
liquid outlet.
For further information about the high pressure float valve, see chapter 8. Appendices .
3.2.5 Condenser
The HeatPAC is equipped with a water-cooled condenser. The condenser is a fully welded plate heat ex-
changer where plates are welded together into cassettes.
R717 condenses between the welded plates which make up the cassettes and cooling water circulates
in the channels between the cassettes.
3.2.6 Receiver
The outlet of the condenser is connected to a small receiver, see Fig. 14 and Fig. 15.