With the air-to-water heat pump ET 102 the ambient heat of the air is used to heat water.
  The heat pump circuit consists of a compressor, an evaporator with fan, a thermostatic expansion valve and a coaxial coil heat exchanger as condenser. All components are clearly arranged in the trainer.
  The compressed refrigerant steam condenses in the outer pipe of the condenser and thereby discharges heat to the water in the inner pipe. The liquid refrigerant evaporates at low pressure in the finned tube evaporator and thereby absorbs heat from the ambient air.
  The hot water circuit consists of a tank, a pump and the condenser as heater. For a continuous operation the generated heat is dissipated via an external cooling water connection. The cooling water flow rate is set via a valve and measured.
  All relevant measured values are recorded by sensors. Displays at the respective locations of measurement indicate the measured values. This makes it easy to assign the measured values to the process. The simultaneous transmission of the measurements to a data recording software enables analysis and the representation of the process in the log p-h diagram. The software also displays the key characteristics variables of the process, such as the compressor pressure ratio and the coefficient of performance. 
  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.
 

- Design and operation of an air-to-water heat pump
- Representation of the thermodynamic cycle in the

  log p-h diagram
- Energy balances
- Determination of important characteristic variables
  * compressor pressure ratio 
  * ideal coefficient of performance
  * real coefficient of performance
- Dependence of the real coefficient of performance

  on the  temperature difference (air-to-water)
- Operating behaviour under load