The principle way of calculation for Type 307 is the same as for Type 107. It is based, on the one hand side, on ordinary calculation equations and, on the other hand, on external performance data that supply the fraction of nominal cooling capacity (fNC) and the fraction of design energy input (fDEI) for the chiller at current operating conditions.

The cooling capacity (QE) and the heating capacity (QG) are calculated by equation (1a) and (1b).

The rated capacity (QE, rated = 15 kW) and the rated thermal COP (COPrated = 0,71) are fixed parameters in the parameter list of the type for the EAW chiller. The heat (QAC), which has to be removed from absorber and condenser to the environment, is calculated as the sum of QE and QG and the thermal COP as their ratio. Finally, the outlet temperatures of each circuit are calculated analogue to equation (2):

In contrast to Type 107 the coefficients fNC and fDEi in equation (1a) and (1b) for Type 307 depend on the hot and cooling water inlet temperatures as well as the chilled water inlet temperature (tEi), instead of the outlet set point temperature tEo, set. Since additionally the load dependency is set to a constant value of one, this disables the implemented control of Type 107. Finally the auxiliary power (Qaux) is excluded from the COP as well as from the QAC calculation, since the parasitic energies (solution pumps, fluid stream pumps, controls, etc.) are normally electrical capacities which should not be mixed with thermal capacities or their heat ratio.