Heat Pump For Cooling And Heating Operation

quick overview :

Refrigeration systems and heat pumps only differ in the definition of their use, but can be of the same design. For example, goods can be refrigerated in a supermarket and the store heated with the waste heat. The store can also be cooled with the same system in the summer. With the cooling and heating operation can be investigated. Different operating modes can be selected via solenoid valves. The refrigeration circuit with compressor and condenser (heat exchanger with fan) includes two evaporators with fans (refrigeration stage and freezing stage) and thermostatic expansion valves. The two evaporators can be connected in parallel or in series. For the connection in series the capillary tube serves as expansion element for the refrigeration stage evaporator. The refrigerant circuit is connected to a glycol-water circuit via a coaxial coil heat exchanger. Via solenoid valves the coaxial coil heat exchanger can be switched as an evaporator or condenser. Thus the glycol-water mixture in the tank can be heated or cooled. In pure cooling operation (without heating function) the heat exchanger with fan as air-cooled condenser dissipates the heat. This heat exchanger can be also switched as an evaporator.

Learning Objectives/Experiments

Design, operation and key components of a heat pump or refrigeration system

Representation of the thermodynamic cycle in the log p-h diagram

Comparing different operating modes

Measurement of compressor capacity and heating or cooling capacity in the glycol-water circuit

Determination of

Efficiency

Coefficient of performance of heat pump and refrigeration system

Specific compressor load

Compressor pressure ratio

Specific cooling capacity

Specific refrigeration capacity

Comparing key figures of heat pump and refrigeration system

Specification

Air-to-water heat pump for cooling or heating operation

Different operating modes selectable via solenoid valves

Refrigeration circuit with compressor, condenser (heat exchanger with fan), 2 evaporators with fan (refrigeration and freezing stage)

Glycol-water circuit with tank, pump and coaxial coil heat exchanger

Coaxial coil heat exchanger and heat exchanger with fan can both be used as condenser or Evaporator in the refrigeration circuit

1 thermostatic expansion valve each for all heat exchangers and evaporators

1 additional evaporation pressure controller and 1 capillary tube for the refrigeration stage evaporator

Displays for temperature, pressure, flow rate and power consumption of the compressor

Refrigerant mass flow rate calculated in the software from recorded measured values

Technical Data

Compressor

refrigeration capacity: 1561W at 5/40°C

power consumption: 759W at 5/40°C

Heat exchanger with fan

transfer area: 1,25m2

volumetric air flow rate: 650m3/h

Evaporators with fan

refrigeration stage transfer area: 1,21m2, volumetric air flow rate: 80m3/h

freezing stage transfer area: 3,62m2, volumetric air flow rate: 125m3/h

Refrigerant: R513A, GWP: 631

filling volume: 1,5kg, CO2-equivalent: 0,9t

Measuring ranges

temperature: 11x -50…150°C

pressure: 2x -1…15bar, 1x -1…24bar

flow rate: 2,5…65g/s

power: 0…1150W

230V, 50Hz, 1 phase

230V, 60Hz, 1 phase; 120V, 60Hz, 1 phase