Chillers Feature Dual Pumps, Compressors To Optimize Control Efficiency
March 1, 2001
Temperature Control:
Chillers Feature DualPumps, Compressors ToOptimize Control Efficiency
Conair's newest line of self-contained portable chillers, the Series 3, have separate pumps for process and recirculation flows. This is said to ensure that flow rates and pressure to process heat exchangers are maintained regardless of changes in system loading.
Large models (20 hp and above) also have dual Copeland scroll compressors on two refrigeration circuits for maximum cooling capacity and operating efficiency. Nominal capacities range from 3.5 to 30 tons for both water- and air-cooled models. The normal temperature range of discharge chilled water is 12 to 70 F.
The Series 3 is the 'top-of-the-line'in Conair's range of 'Good-Better-Best' portable chillers. Prices start at$9800.
The line also includes Series 1 models, which are priced 'aggressively' and offer a choice of PLC or simplified,low-cost controls (May '00 PA, p 27) and the Series 2, which offers PLC controls as standard, along with brazed-plate condensers.
Features cited for Series 3 chillers include:
40% smaller footprint than competitive units of comparable capacities (36 x 48 in. to 48 x 48 in.).
Hot-gas bypass on all compressors to help balance loading with process requirements
PLC controls with 'plain-English' displays
Non-ferrous plumbing
Stainless steel tanks that allow for the use of overhead piping
Top air discharge on air-cooled models to direct heated air away from operators
Stainless steel side panels and aluminum frame.
The small footprint is the result of design innovations including more compact condensers. Conair says it uses a brazed-plate condenser in water-cooled models, instead of traditional shell and tube, for example, replacing an 8-in x 6-ft tube condenser with a 12- x 12- x 18-in. brazed plate in a 20-ton chiller. Condensers in the air-cooled models are also said to be smaller.
The PLC controls have a multi-button user interface with a two-line LCD to indicatesetpoints, chiller status, alarms and diagnostics. Indicator lights show when compressors, pumps and alarms are activated. Automatic fine-tuning of the PID control parameters provide uniform temperature control, regardless of light or heavy external loading.
Conair
Pittsburgh, PA
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