AIR-COOLED LIQUID CHILLERS 30XA 252-1702
Remote Management (EMM option)
The Energy Management Module (EMM) offers extended remote control possibilities: - Room temperature: Permits set-point reset based on the building indoor air temperature (if Carrier thermostat are installed) - Set-point reset: Ensures reset of the cooling set-point based on a 4-20 mA or 0-10 V signal - Demand limit: Permits limitation of the maximum chiller capacity based on 0-10 V signal - Demand limit 1 and 2: Closing of these contacts limits the maximum chiller capacity to two predeﬁned values - User safety: This contact can be used for any customer safety loop; opening the contact generates a speciﬁc alarm Ice storage end: When ice storage has ﬁnished, this input permits return to the second set-point (unoccupied mode) Time schedule override: Closing of this contact cancels the time schedule effects Out of service: This signal indicates that the chiller is completelt out of service Chiller capacity: This analogue output (0-10 V) gives an immediate indication of the chiller capacity Alert indication: This volt-free contact indicates the necessity to carry out a maintenance operation or the presence of a minor fault Compressors running status: Set of outputs (as many as the compressors number) indicating which compressors are running.
Total heat reclaim (option 50)
Suitable for heating, domestic hot water preparation, agriculture and food industry, industrial processes and other hot-water requirements. With the total heat reclaim option it is possible to reduce the energy consumption bill considerably compared to conventional heating equipment such as fossil fuel boilers or electric water tanks. 65 60 55 50 45 40
If hot water production is required, the compressor discharge gases are directed towards the heat reclaim condenser. The refrigerant releases its heat to the hot water that leaves the condenser at a temperature of up to 60 °C. In this way 100% of the heat rejected by the liquid chiller can be used to produce hot water. When the demand for heat is satisﬁed, the hot gas is again directed towards the air condenser where the heat is rejected to the outside air by the fans. Hot water temperature control is ensured by the chiller Touch Pilot control that independently controls the reclaim operation of each refrigerant circuit. Note: Heat reclaim is only possible, if the unit produces cold water at the same time. Condenser water temperature (°C)
Entering temperature at start-up Entering temperature during operation Leaving temperature during operation Evaporator water temperature (°C) Entering temperature at start-up Entering temperature during operation
35 30 25 20 0 5 10 15
12.5* 20 25 6.8
55 55 60 45 21
Part load operating limits (evaporator leaving water temperature = 7 °C)
60 55 50 45 40 100
The entering water temperature at start-up must not fall below 12.5 °C. For installations with a lower temperature a three-way valve must be used.
Note: If the evaporator leaving water temperature is below 4 °C, a glycol-water solution or the frost protection option must be used.
In part-load operation, the limitation of the condenser leaving water temperature is due to the operating range of the screw compressor. If the condenser leaving water temperature is above the limit value given in the curves on the right, the unit will automatically change over to the mode without heat recovery:
Full load Part load limit, approx. 60% Minimum load limit, approx. 30%