Hi all,
We are trying to model more accurately a heat pump for which the performance should ideally be read out from a text or excel file.
The data depend on 3 parameters (outdoor and indoor air temperature, requested output).
Part load ratios are hard to define, as the actual capacity depends on the model type and the outdoor conditions. So it seems logic to use excell. However, values are not a function, but should be looked up in the excell table, potentially interpolated, ... and to make it more challenging, the final SPF does depend on PLR, outdoor and indoor temperature. So it is not just using the external temperature and required capacity to calculate PLR and consequently use that PLR plus indoor temperature to calculate SPF.
Calling 6 different excell files in a simulation of 8760*4 steps will take considerable time. The current standard TRNSYS look up model allows two independent parameters defining the output ... so insufficiently accurate.
any suggestions on how to solve that?
thanks,
leen