How a Chiller Works: The Refrigeration Cycle
A vapour-compression chiller uses an evaporator, compressor, condenser and expansion device to move heat from a cooler process to warmer surroundings. Electrical energy is required to drive this transfer.
Evaporator and compressor
Refrigerant absorbs heat and evaporates inside the evaporator, cooling the process fluid. The compressor increases the pressure and temperature of the vapour. Suitable suction conditions and protection against liquid carryover are essential to compressor operation.
Condenser and expansion device
The refrigerant releases heat and condenses in the condenser. Fans reject the heat in an air-cooled unit; a separate condenser-water circuit performs this function in a water-cooled unit. The expansion device reduces pressure and regulates evaporator feed. It does not independently determine the complete system capacity.
Why the control system matters
Temperature sensors, flow proving and pressure protection work together. Low flow, a fouled heat exchanger or recirculation of hot discharge air can prevent the unit from delivering its rated duty. Settings must follow the model operating envelope rather than values copied from another installation.
Project inputs and calculation boundaries
For a quotation, specify approximate heat duty, fluid, inlet and outlet temperatures, flow, pressure loss and operating hours. Design ambient conditions, indoor or outdoor location and electrical infrastructure are also selection inputs. Flow and temperature readings must represent the same operating point. Do not transfer a catalogue capacity directly to different temperatures; confirm model performance at the required duty.
Commissioning and operating records
Check circuit cleanliness, filtration, air removal, proven flow and sensor readings. Record reference water temperatures and load conditions during commissioning. These values provide a baseline for maintenance and alarm investigations. Confirm pumps, tanks, connections and control options against the agreed quotation scope.
Frequently asked questions
Is the series capacity range sufficient for final selection?
No. Confirm the actual model at the required fluid temperature, ambient conditions, fluid properties and hydraulic duty.
Is cooling capacity the electrical consumption?
No. Cooling kW and electrical-input kW are different quantities. An energy assessment also needs actual load and operating hours.
What information is needed for a quotation?
Provide the industry or equipment, target temperature, approximate duty, flow, ambient conditions, operating hours and details of the existing system.
These explanations provide general engineering guidance. Examples are not field measurements or performance guarantees for a particular model.