Airedale SmartCool 11-233kW - Manual (Page 166)

SmartCool
TM
- D Precision Air Conditioning
166
Precision Air Conditioning
Installation, Maintenance and Commissioning Manual :6877419 02/2013
Commissioning Data
Suction Throttle Valve
(X2X2, X2C0 W2W2, W2C0
& W2F0 Models)
An electrically operated suction throttle valve can be fitted to provide accurate
capacity control from 50% to 100% depending on the room load. Precise
temperature control is obtained as a result of modulating the refrigerant flow in the
evaporator by throttling the valve on the suction line.
50%
55%
60%
65%
70%
75%
80%
85%
90%
95%
100%
Valve Adjustment
C
ap
ac
it
y
(
%)
Fully Closed Fully Open
1
1 Capacity @ 24°C / 45% RH return air conditions
The suction throttle valve in essence reduces the flow of refrigerant back to the
compressor. Reducing the cooling effect of the system. With this reduced quantity
of refrigerant returning to the compressor the superheat is increased causing the
discharge temperature to also increase. The discharge temperature must be
monitored to ensure that the compressor does not get too hot (reduced cooling
from the suction gas). Also with the reduced flow of refrigerant the oil level
returned to the compressor has to be monitored very closely. Low level of oil in a
system can cause compressor failure.
Hot Gas Re-Heat (HGRH)
(DX Models fitted with
Humidification)
During dehumidification, the hot gas re-heat coil re-heats the cooled air from the
evaporator coil using hot gas from the discharge line to maintain the room setpoint.
Normally reheating of the air during dehumidification is performed by electric heating
which requires additional power input. By utilising the available hot gas, the HGRH
option does not require additional power input and is therefore far more energy
efficient than electric heating.
Only the lowest stage of compressor operation is required for de-humidification in the
smartcool. This further reduces power consumption.
Energy Input Comparison during de-humidification
HGRH vs. Electric Heating
C
omm
iss
ion
ing