Modelling of Inverter Heat Pumps in TRNSYS
Abstract
Validated simulation models are important for the development of advanced system design and control strategies. In this contribution we present an approach to model inverter heat pumps by combination of multiple single speed models in TRNSYS. Performance data of a brine/water heat pump is determined by experimental investigations for three levels of inverter frequency. Deviation in efficiency is observed at source temperatures above 10 °C, with lower inverter frequencies reaching higher coefficients of performance. Each level of inverter frequency is modelled with one instance of TRNSYS Type 401. To validate the modelling approach, we use experimental data of load variations. Relative deviations show an overestimation of heat transferred at condenser of 〖∆Q〗_(cond,rel)= 3.7 % and electric energy used at compressor of 〖∆P〗_(el,rel)=2 % in the simulation Overall, the approach is able to represent the operational behavior of an inverter heat pump and can be suggested for system control strategy development by means of simulations.