Carrier AQUAFORCE 30XA080-500 Product Data

Also see for AQUAFORCE 30XA080: Installation instructions Controls, start-up, operation, service and troubleshooting instructions Installation instructions Controls, start-up, operation, service and troubleshooting instructions

Carrier AQUAFORCE 30XA080-500 Product Data Manual pdf 30 page image

30Carrier’s Packaged Chiller Builder Selection Program pro-vides quick, easy selection of Carrier’s air-cooled liquidchillers. The program considers specific temperature, fluidand flow requirements among other factors such as foulingand altitude corrections.Before selecting a chiller, consider the following points:Leaving water temperature (LWT)• If the LWT is less than 40 F (4.4 C), loop freeze protec-tion to a minimum of 15° F (8.3° C) below the LWT setpoint is required. The medium temperature brine optionis also required.• If the LWT requirement is greater than 60 F (15.5 C), amixing loop is required.Entering water temperature (EWT)• If the EWT requirement is greater than 70 F (21.1 C), amixing loop is required. The EWT should not exceed70 F (21.1 C) for extended operation. Pulldown can beaccomplished from 95 F (35 C).Cooler flow rate or cooler delta-T:• The cooler delta-T (EWT – LWT) must fall between5 and 20° F (2.8 to 11.1° C).• For larger or smaller delta-T applications, a mixing loopis required.• If the cooler flow is variable and the rate of change offlow should not exceed 10% per minute, a loopvolume of greater than 3 gallons per ton (3.2 l/kW) isrecommended.Cooler pressure drop:• A high cooler pressure drop can be expected when thecooler delta-T is low. A mixing loop can help to alleviatethis situation.Alternatively, consider a reduced pass option for a lowerdelta-T.• A low cooler pressure drop can be expected whencooler delta-T is high.• Consider the plus-one-pass cooler option to increasedelta-T and performance.Water quality, fouling factor:• Poor water quality can increase the required cooler foul-ing factor.• Higher than standard fouling factors lead to lowercapacity and higher input kW from a given chiller sizecompared to running the same application with betterquality water (and lower fouling factors).Operation below 32 F (0° C):• Low ambient temperature head pressure control isrequired.• Consider wind baffles if average wind speed is greaterthan 5 mph (8 km/h).• Consider higher loop volumes, 6 to 10 gallons pernominal ton (6.5 to 10.8 l/kW).• Loop freeze protection with glycol is strongly recom-mended to a minimum of 15° F (8.3° C) below lowestanticipated ambient temperature.• Chilled water pump control is strongly recommended;otherwise override capability is required.Chiller idle below 32 F (0° C):• Loop freeze protection with glycol is strongly recom-mended to a minimum of 15° F (8.3° C) below lowestanticipated ambient temperature.• Chilled water pump control is strongly recommended;otherwise override capability is required.• Drain the cooler — This will require a small amount ofglycol for residual water. Cooler heaters will need to bedisconnected.• Highest allowable ambient air temperature is 125 F(52 C).NOTE: It may be necessary to select the high ambientoption to obtain performance with ambient air tempera-tures approaching 125 F (52 C).Cooling capacity requirement:• Do not oversize the chillers by more than 15% at designconditions.• If capacity control is required below the standard mini-mum step of unloading, the minimum load controloption should be employed. (See Selection Guide.)Coil corrosion requirements:• Coastal application• Industrial application• Coastal/industrial application• Urban application• FarmingTemperature reset:• Return water (standard)• Outside air temperature (standard)• Space temperature (accessory sensor required)• 4 to 20 mA (requires an Energy Management Module)Demand limit:• 2-step (requires an Energy Management Module)• 4 to 20 mA (requires an Energy Management Module)• CCN LoadshedSelection procedure