What is a chiller?
A chiller is a machine that removes heat from a liquid via a vapor-compression cycle. A vapor-compression liquid chiller comprises the four major components of the vapor-compression refrigeration cycle (compressor, condenser [shown as air cooled], some form of metering device, and evaporator . In a chiller the heat removal process starts in the evaporator where heat is absorbed from the process, is carried through the compressor, and is liberated within the condenser to the ambient. The other major components of a chiller are the pump that circulates fluid to the load and back, the reservoir that holds the chilled fluid, and the temperature controller that senses the temperature and controls the refrigeration circuit to control the reservoir temperature to the desired temperature set point. Chillers can rid themselves of the heat removed in three ways: air cooled, water cooled, or split system where the condenser is mounted outdoors. These chillers can implement a variety of refrigerants. Most often, pure water is chilled (water chillers), but this water may also contain a percentage of glycol/water, propylene/water, and/or corrosion inhibitors: other fluids such as thin oils can be chilled as well.
What is Industrial Chiller Technology?
Industrial chillers typically come as complete packaged closed-loop systems, including the chiller unit, condenser, and pump station with recirculating pump, expansion valve, no-flow shutdown, internal cold water reservoir, and temperature control. The internal reservoir helps maintain cold liquid temperature and prevents temperature spikes from occurring. Closed loop industrial chillers re-circulate a clean coolant or clean fluid with anti corrosion additives at a constant temperature and pressure to increase the stability and reproducibility of liquid-cooled machines and instruments. The cooling fluid flows from the chiller to the application's point of use and back.
Industrial chillers control the temperature of a liquid in an open reservoir by constantly recirculating it. The liquid is drawn from the tank, pumped through the external load, and back through the evaporator/heat exchanger to the reservoir. An adjustable thermostat senses the makeup liquid temperature, cycling the chiller to maintain a constant temperature in the tank.
Most industrial chillers use refrigeration as the media for cooling, but some rely on simpler techniques such as air or water flowing over coils containing the coolant to regulate temperature. Water is the most commonly used coolant within process chillers, although coolant mixtures using Ethylene Glycol/Water or Propylene Glycol/Water mixtures are frequently employed to prevent water from freezing at low temperatures, or in outdoor operation.