Potential Savings for Induction Motor Drive Systems for HVAC Applications

This paper investigates the potential savings using improved motor and power electronic technology as well as improved motor control, for different HVAC load profiles. A 4-pole, 4kW IM has mainly been used in the investigation, where different energy labels (eff1,eff2 and eff3), different voltage/frequency (V/Hz) control have been investigated. Theoretical calculations have been used in order to analyze the saving potential for four different load profiles. The general conclusion is that economical savings will be made, both for an IM and frequency converter replacement in spite of the investment costs. The analysis also shows that the choice between an eff2 and eff1 IM, for the given load profiles, always generate the highest saving for the eff1 IM also in economical terms, incorporating the increased cost for an eff1 motor. It is interesting to note that, during the time period 1998-2003, eff2 label took 86% of the market share compared to eff1 8% and eff3 6%. It is also shown that losses introduced by the commonly used over dimensioning of the pump and fan motor can result in increased energy efficiency with appropriate converter control compared with the use of a motor with lower rating, which is opposite to the case when using a drive without a converter