The HL 313 trainer can be used to demonstrate the principal aspects of solar thermal domestic water heating in a system with components used in real world applications.
  Radiant energy is converted into heat in a commercially available flat collector and transferred to a heat transfer fluid in the solar circuit. The heat then gets into the hot water circuit via a heat exchanger.
  A solar regulator controls the pumps for the hot water and solar circuits. The solar circuit is protected by an expansion tank and a safety valve.
  The trainer has been designed so that it is possible to carry out a complete preheating as part of a practical experiment.
  The temperatures in the storage tank, at the outlet from and the inlet to the collector are measured, as is the flow in the solar circuit. Additionally, as in practice, the temperatures of the inlet and return are displayed on the solar circulation station.
  In order to ensure there is sufficient illuminance, the system should be operated with solar radiation or the optionally available HL 313.01 Artificial Light Source.
  The well-structured instructional material sets out the basic principles and provides a step-by-step guide through the experiments.

- Familiarisation with the functions of the flat collector

   and the solar circuit
- Determining the net power
- Relationship between flow and net power
- Determining the collector efficiency
- Relationship between temperature difference

  (collector/environment) and collector efficiency