Recirculating chillers are liquid cooling systems that offer precise temperature control and/or cooling below ambient temperatures (Figure 1). Chillers have many options so that they can be easily integrated into a wide variety of applications. These recirculating chiller options include special application options, fluid compatibility options, protection options, and convenience options.
Special applications and fluid compatibility chiller options, featured below, include a heater, internal insulation package, low temperature operation, water-cooled condenser, and 0.1°C set point
When the ambient temperature is below your required chiller set point temperature, a heater may be needed. This option is especially helpful when equipment is turned off nightly or turned on and off in a cold environment. The heater option is a submerged 2000 W, 230V electric resistance heater that allows a set point temperature to be reached faster during cold start-ups or during frequent coolant set point cycling. It has a built-in over temperature (non-adjustable) shut-off. When the coolant is within 3°C of the set temperature, the heater shuts off and the refrigeration cycle takes over until the set temperature is reached. This option is available on Aavid’s RC011 to RC045 models. It does not extend the coolant temperature range.
Internal Insulation Package
An internal insulation package greatly reduces the formation of condensation on the tank, pump head, and coolant lines when the chiller coolant set temperature is below the ambient dew point. It helps prevent corrosion within the chiller as well as damage to electronics from drips. An internal insulation package is recommended for applications where the set temperature is 10°C or less as well as when the ambient temperature is above 25°C.
Low Temperature Operation
For low temperature set points (-5°C to 25°C), the low temperature operation option maximizes performance and provides more low temperature cooling capacity than a standard chiller. An internal insulation package is required when selecting this option. Low temperature operation is used in lasers, x-ray cooling, analytical instrumentation, and more.
Another option is a water-cooled condenser. This option allows for rejecting heat to an external liquid coolant source via a brazed plate liquid-to-liquid condenser instead of rejecting it to ambient air with a liquid-to-air condenser. This option prevents room warming and possible air conditioning overload. Also, water-cooled chillers are quieter because there is no condenser fan. The liquid coolant source is typically facility water, but it can also be another chiller located in a different room. The chiller cooling capacity is based on a facility water temperature of 75°F (24°C) at a pressure less than 100 psi. Figure 2 shows the recommended facility water flow rates for each Aavid recirculating chiller. Contact Aavid’s applications engineering for required facility flow rates at different temperatures.
Figure 2: Recommended Facility Water Flow Rates for Aavid Recirculating Chillers
Flow Rate (min)
Check out our Recirculating Chiller Section for more information about their wetted materials or contact our Engineering Team to help determine material compatibility in your liquid cooling system.