R853 Vapour Jet Refrigerator/Heat Pump

R853 Vapour Jet Refrigerator/Heat Pump

A bench top example of a refrigerator/heat pump that is driven by a heat source. The unit operates on a combined Rankine and vapour compression refrigeration cycle using a low pressure, non-toxic ozone friendly refrigerant.

A simple ejector (or thermo-compressor) performs the expansion and compression processes involved in the combined cycles. A small electric motor drives the pump of the Rankine cycle. The heat source is electrically heated and produces high pressure vapour to drive the ejector.

Supplied in standard form with an electric heat source, an optional set of Solar Panels and Installation Package (F820S) is available to demonstrate the generation of a refrigerating effect directly from solar radiation.

R853 Vapour Jet Refrigerator/Heat Pump

Panel:  High quality ABS plastic on which the following are mounted:

Steam Generator:  Rectangular glass reinforced plastic insulated vessel fitted with 1.5kW immersion heater and containing the refrigerant vapour generator.

Refrigerant Vapour Generator:  Cylindrical stainless steel shell, 75mm dia x 200mm long, with dished ends – fitted with sight glass and pre-heating coil.

Ejector or ThermoCompressor:  Nozzle: Convergent-divergent, throat diameter 1.7mm.

Diffuser: With combining cone, parallel and divergent portions.

Evaporator:  Thick walled glass cylinder fitted with metal end plates and P.T.F.E seals.  Evaporator incorporating a 500W heater controlled by a variable transformer and a float type expansion valve.

Condenser:  Thick walled glass cylinder fitted with water cooling coil.  Surface area of coil: 0.1m2.

Feed Pump:  Reciprocating plunger type pump fitted with P.T.F.E. seals and water jacket, driven by electric motor through worm reduction gearbox to give approximately 60 double strokes/minute.

Throttle Valve:  Manually adjustable to vary nozzle inlet pressure.


Thermometer:  Digital Ni/A1 electronic thermometer with 0.1oC resolution and 12 way selector connected to 9 thermocouples to measure all important temperatures.

Pressure Gauges:  Two 0 to 800 kNm-2  to indicate refrigerant vapour generator and nozzle inlet pressure. Two – 100 to + 100 kNm-2 to indicate evaporator and condenser pressure.

Flow Meter:  Variable area glass tube type fitted with control valve to measure water flow rate through condenser.  Range 0 to 75g s-1.

Voltmeter and  Ammeter:  To measure power input to evaporator.  Ranges 0 to 250Vand 0 to 3A respectively.

Safety features

Pressure Relief Valves:  Fitted to vapour generator, evaporator and condenser.

High Pressure Cut Out  Switches:  Fitted to vapour generator and condenser.

Low Water Flow Switch:  To switch off power supply if insufficient water flows through the condenser.

Solenoid Valve:  To isolate vapour generator from ejector, evaporator and condenser.

High Temperature Cut Out:  Fitted to all heater elements.  All circuits are protected by a fuse.


  • Analysis of the combined Rankine and Vapour Compression Cycle.
  •  Demonstration of the characteristics of an ejector or thermo compressor.
  •  Production of performance curves as a refrigerator and comparison with ideal Rankin/Vapour Compression cycle.
  • Production of performance curves as a heat pump and comparison with ideal Rankine/Vapour compression Cycle.
  • Investigation of entrainment mass ratio at various pressures.
  • Demonstration of ‘adiabatic’ mixing of hot and cold vapour.
  • Demonstration of ’adiabatic’ throttling.


A:  2.5kW, 220-240 Volts Single Phase 50Hz(With earth/ground).


B:  2.5kW, 110-125 Volts Single Phase, 60Hz (With earth/ground).


250 litres/hour at 15m head. 

Water temperature should not exceed 22oC if a useful range of test conditions are to be investigated.