Modelling of variable speed air-conditioning systems based on experimental data and performance curves

[摘要] Executive summaryThis report presents a variable-speed air conditioner (AC) modelling method in the context of a single room simulation tool. Its goal is to represent the behaviour of a single unit to enable future electric power predictions and management for a population of air-conditioners.We started our model with the Matlab demo “sldemo_househeat” which contained a thermodynamic model of a house and a heater. We changed the heater first for a constant speed air conditioner and then for a variable-speed air conditioner.The impact of elevated ambient temperatures on capacity and energy input was mapped in our model as third-order functions obtained through the manufacturers’ performance tables. In these tables, we can find the units’ cooling capacity and input power as functions of evaporation temperature for several condensation temperatures.Later we explain how to set the model parameters and then we simulate some experiments carried out in the Climate Control Test Facility (CCFT) laboratory at the CSIRO Energy Centre in Newcastle, NSW. These experiments were not specifically developed to our project; they were conceived for another summer project on which the student was studying the effect of different demand response modes (DRM) to a Panasonic unit. Some experiments were recorded for our purpose one year ago. However, the unit (a Daikin AC) was performing like a constant speed air conditioner with its input power oscillating even when all the ambient conditions were in steady state.We found that our model present good results if all the parameters are well defined and correctly set. The user should try setting different parameters before coming up with a good response. The main differences between the model simulation and the experimental data are related to the different modes each AC operates and with errors in the room parameters. When simulating a population of ACs containing slightly different parameters, these differences may not be significant.This report also contains some theory related to the subject and some words for future works. All the AC specifications and tables used in our model are in the appendix.

[发布日期] 2014-02-22 [发布机构] CSIRO

[学科分类] 地球科学(综合)