AHI Carrier Catalog | Page 245

WATER-COOLED SCREW COMPRESSOR LIQUID CHILLERS 30HXC 080-375 Operating limits, units for very low temperature (option 6) * ** 30HXC Minimum flow rate, l/s* Maximum flow rate, l/s** 090 110 130 155 175 200 230 260 310 345 8 10.6 12.4 14.5 15.6 20.5 21 24.1 29.6 30.2 15.7 21.3 25.1 28.1 33 38 39.7 48.3 62 63 For very low temperature applications the amount of antifreeze solution added is critical for the unit operation. The following amounts are required: Evaporator leaving water temperature, °C Ethylene glycol, % Propylene glycol, % -6 -7 -8 -9 -10 25 28 30 33 35 27 30 NA NA NA COOLING Evaporator water flow rate with 35% ethylene glycol Based on a Reynolds number of 4000. Based on a water velocity of 3.6 m/s. Minimum flow rate, l/s* Maximum flow rate, l/s** 090 110 130 155 175 200 230 260 310 345 11.1 14.2 16.7 19.1 21.1 25.1 27.4 32.3 40 40.6 15.7 21.3 25.1 28.1 33 38 39.7 48.3 62 63 Based on a Reynolds number of 4000. Based on a water velocity of 3.6 m/s. Operating range, units for very low temperature (option 6) Condenser entering water temperature, °C 50 48 44 D 20 15 13 C -7 Evaporator leaving water temperature, °C A R R I E R 2 0 1 6 / 2 0 4 13 15 Evaporator leaving water temperature, °C Notes: 1. Evaporator ΔT = 4 K max. - condenser ΔT = 5 K 2. Operating range applicable for full and reduced load. 3. At full load with a condenser water entering temperature below 20°C, a three-way valve must be used to maintain the correct condensing temperature. C AIR TREATMENT Operating range 30% propylene glycol Condenser entering water temperature, °C Operating range 35% ethylene glycol 0 1 7 Legend C Unit operating with condensing pressure control with an analogue water control valve. For transient operating modes (start-up and part load), the unit can operate down to a condenser entering water temperature of 13°C. D Operation permitted, but performance is not optimised. 245 CONTROLS * ** 30HXC HEATING HEATING Evaporator water flow rate with 30% propylene glycol