Water-Cooled Test Chamber Information
Why do some larger test chambers need cooling water? The water is used to cool the large capacity refrigeration systems at its condenser (where the refrigerant changes phase from a gas to a “condensed” liquid). Our smaller chambers have air-cooled condensers that expel the heat directly to the room (similar to a home refrigerator). But because the larger compressors used with our high performance systems would create too much heat, water cooling is preferred. Water cooling is also more efficient and less affected by temperature changes. The larger capacity, higher HP systems, generally start at 6HP and above, however some 6HP and even 10HP units can be built with integral air-cooled condensers.
Cooling water can be from any source, but the following basic requirements are needed:
- Water should be clean.
- Water temperature should be between 5 and 30°C (41 to 86°F).
- The pressure delta between the inlet and outlet should be 207-275kPa (30-40psi).
- The flow rate specified for the equipment must be available at all times.
Because the quantity of water required is too expensive to draw from a city water system and dump down the sewer without recirculation (and possibly illegal), most customers select external cooling systems, sold and installed by other suppliers, that re-circulate the water. This is especially beneficial when more than one system is involved, as one cooler can handle multiple systems. There are two types of coolers:
- Evaporative coolers, (Cooling Towers) which use the evaporation of a water spray to cool the re-circulating water. This method still consumes some water via the evaporation and cannot cool to lower temperature.
- Chilled coolers, which use a refrigeration system to cool the water. This system then uses an air cooled condenser to expel the heat outdoors.
Either system may use ethylene glycol (anti-freeze) mixed with the water to extend the temperature range of the cooling loop, mostly to avoid freezing. The use of anti-freeze makes the cooling less efficient, which means a higher overall flow rate is required.
All CSZ water cooled refrigeration systems include a water regulating throttle valve that only allows as much water flow as is required to maintain the outlet water temperature of about 35°C (95°F). The GPM (gallons per minute) or LPM (Liters per minute) value we specify in the quotation or on the water chart is a maximum flow rate that may be required of the chiller/cooler.
Remote (outside) Air-Cooled Condensers are also available as an option on most large capacity refrigeration systems. These systems require installation for each chamber.