Product number: R715

The vapour compression refrigeration cycle is used in many industrial, medical and domestic situations throughout the world. Air conditioning, food and medical preservation and transport all rely on the use of refrigeration plant. It is essential therefore that student engineers intending to design or utilise such plant are fully aware of the parameters affecting the performance of the vapour compression refrigeration cycle.

A refrigerator is defined as a machine whose prime function is to remove heat from a low temperature region. The most common type of refrigerator or heat pump operates on the Vapour Compression Cycle and requires a work input.

The Hilton Refrigeration Laboratory Unit R715 is a fully instrumented refrigerant R134a vapour compression refrigerator of this form and has been designed to enable students to safely study the cycle in detail. It has a belt driven compressor, electrically heated evaporator, thermostatic expansion valve and water cooled condenser. Operating parameters can be varied by adjustment of condenser cooling water flow and electrically heated evaporator supply voltage.

Components have a low thermal mass resulting in immediate response to control variations and rapid stabilisation.
Instrumentation includes all relevant temperatures, condenser pressure, evaporator pressure, refrigerant and cooling water flow rates, evaporator and motor power, motor torque and compressor speed.

Specifications and resources

Panel: High quality GRP.
Refrigerant: R134a.
Digital Thermometer: 6 way type K indicator with 0.1°C resolution.
Wattmeter: Allows measurement of the power input to either evaporator or motor.
Voltage Controller: To vary evaporator load.
Variable Area Flowmeters x 2: Variable area types to indicator R134a and H20 flow rates.
Pressure Gauges x 2: to indicate R134a pressure in evaporator and condenser.
Spring Balance and Tachometer: Together allow measurement of power required to drive the compressor.
Expansion Valve: Thermostatically controlled type.
Evaporator: Electrically heated device.
Compressor: (Internally mounted) Twin cylinder belt driven unit.
- Condenser pressure and evaporator heater temperature limited by automatic cut-outs.
- All electrical components connected to common earth.
- Unit protected by miniature circuit breaker and residual current circuit breaker.