Features like microprocessor control board with lifetime exchange, micro switches in lieu of bubble switches, and an insulated polyethylene reservoir are standard on the new EP1 Series of portable chillers from Conair. The EP1 Series portable chillers are designed for 1 to 3 ton applications, while the EP2 Series includes chillers from 4 to 43 tons. Conair notes that both ranges include air-cooled, water-cooled and remote-condenser models, adding that both lines' water circuits utilize non-ferrous materials for the evaporator, pump, reservoir, and piping.
Other standard features that are oftentimes offered up as options, include:
- Cleanable shell-and-tube condensers on water-cooled models
- Process-water Y-strainers that protect against evaporator contamination
- Heavy-duty cabinet enclosure and casters
Conair says the EP1 and EP2 lines are designed and built for use with non-ozone-depleting refrigerants. EP1 Series chillers are customized to lower-tonnage applications, featuring scroll compressors on 2- and 3-ton chillers and rotary compressors on the 1-ton models. The EP1 units are protected by a 2.5 minute anti-cycle timer to prevent excessive compressor cycling. A freezestat safety switch, with solid-state sensor, prevents evaporator freeze-up. Water- and air-cooled EP1 units ship with a full refrigerant charge, and units with remote air-cooled condenser ship with a nitrogen charge.
The EP2 chillers can be supplied optionally with a programmable-logic controller (PLC). The system has two LED displays for 'Setpoint' and 'Actual' temperatures and LED diagnostic lights for multiple fault conditions. 3-phase power monitoring protects the unit from damage due to electrical phase reversal or loss of phase. The PID control algorithm provides ±1°F/°C accuracy.
Optional PLC controls offer a touch-sensitive operator interface with system information and alarms presented in text instead of lights and codes. The PLC control can be further upgraded with refrigeration-pressure transducers with sensor fault alarms, a process flow meter, and setpoint ambient tracking or optional remote control. The unit is networkable through a ModBus RTU communications port.
Packaged air-cooled EP2 chillers are available in sizes from 4 to 30 tons. Water-cooled and remote-condenser units can be sized from 5 to 43 tons, with scroll compressors used on all models. Units that are 20 tons and larger feature dual compressors, which can be staged to increase temperature accuracy in low-load situations, reduce wear and tear on the compressor, and conserve energy. A stepper-motor-driven hot-gas bypass system is also used under low-load conditions.
Condensers on air-cooled chillers feature aluminum micro channels that require less refrigerant while exposing it to a larger surface area for greater energy efficiency. Water-condensed chillers have a cleanable shell-and-tube construction and are equipped with a condenser-water regulating valve to provide constant head pressure. Remote condenser units are designed with copper-tube/aluminum-fin coils and direct-drive multi-blade propeller fans with venture orifices to optimize efficiency. Fan sections are divided to prevent 'wind-milling' du