The heat relationship 2 is defined as the relation between available heat, here Q2, and actuation heat to be expended, here Q1 = Q1' + Q1":
2 = Q2/Q1 = Q2/(Q1' + Q1")
The heat relationship 2 of the heat transformer is, like that of the absorption heat pump, largely dependent upon the temperature elevation and operational conditions of the plant.
The elementary circulation of the absorption heat transformer is represented schematically in the pressure-temperature diagram in Fig. 59. Not taking into account the condensate and solution pumps, there are again four components which exchange energy with the environment.
Fig. 59 Pressure-temperature diagram for a solar powered cooling model
These are: At the higher pressure, the evaporator at temperature T1 and the absorber at temperature T2, and at the lower pressure, the condenser at temperature T0 and the generator at temperature T1. The two slanted connecting lines between the condenser and the evaporator on the one hand, and between the generator and the absorber on the other hand, again symbolise the phase limit line of the work material and/or the boiling point curve of the absorbing solution. The mass flow of the work material now runs through the components in a counter-clockwise direction.