10
C6.2.24/1014-0215/E
Copeland Scroll compressors ZFD13KVE to ZFD25KVE are vapour injection only. Liquid
injection alone is not possible. For compressor model ZFD41K5E both liquid injection and
vapour injection are possible.
Dedicated discharge temperature thermostats (DLT) shall be used for R407A, R407F, R448A
and R449A applications and can also be used for R404A. The R407A/R407F/R448A/R449A
dedicated discharge thermostat has a cut-out setting of 130°C ± 4K with closing at 101°C ± 8K.
It should be installed approximately 120 mm from the discharge valve outlet.
3.3.1 Vapour injection (EVI = Economized Vapour Injection)
Compressor models ZFD13KVE to ZFD25KVE and ZFD41K5E can be used with R404A,
R407A, R407F, R448A and R449A refrigerants and vapour injection.
These compressors are equipped with a vapour injection connection for economizer operation.
Economizing can be achieved by using a subcooling circuit similar to the circuit shown in
Figure 15
. This increases the refrigeration capacity and the system efficiency.
The line diagram shows a system configuration for the economizer cycle. A heat exchanger is
used to provide additional subcooling to the refrigerant before it enters the evaporator. This
subcooling process provides the increased capacity gain measured in the system.
The evaporated refrigerant through the heat exchanger (economizer) is injected into the
compressors and provides additional cooling at higher compression ratios.
Figure 12: Vapour inj ection line diagram
The application envelopes for the use of R407A and R407F refrigerants with vapour injection are
significantly limited, because of possible high discharge temperatures. Special attention should
be paid to the maximum suction gas temperature / superheat values.
NOTE:
For further information on vapour injection see Technical Information C7.19.2
"
ZF* Refrigeration Copeland Scroll™ Compressors
Using R407A and R407F in Low
Temperature Applications".
3.3.2 Wet vapour injection (vapour inj liquid injection)
Compressor models ZFD13KVE to ZFD25KVE and ZFD41K5E can be used with R407A and
R407F refrigerants and wet vapour injection.
The operating envelopes for R407A and R407F low temperature applications can be enlarged
thanks to the use of wet vapour injection, ie, a combination of vapour injection and liquid
injection (DTC valve) (see
Figures 6 & 7
in Chapter 2.4.2).
The wet vapour injection cycle showing the main components is shown in
Figure 16
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