Comparison and analysis of energy savings by the application of variable speed drives in HVAC systems monitored via a BMS at Malta International Airport

Abstract

The main aim of this study was to determine what energy savings could be obtained when making use of a variable speed drive. The MIA facilities department chose one of the three main plant rooms, being the East plant room, to introduce a variable speed drive to each motor. Once a better picture is obtained of what savings can be obtained, how much carbon emissions are reduced and the payback of the variable speed drive, a decision will be taken on whether to also replace the other plant rooms. This study provides an explanation on the different methods for driving an induction motor and the advantages and disadvantages of each method. This study concentrates on the air handling unit fans and did not take other motors, such as pump motors into consideration. The main aim these motors were studied, is due to the fact that the air handling unit fans, do not need to operate at full speed constantly and this therefore means that the variable speed drives can be utilized to reduce the speed of the motor and therefore reduce power. In this study, before and after readings of the supply power are taken from one AHU in the East plant room. Simulations are also done, to compare the results obtained, with those in practice. Once the results are obtained, the percentage savings obtained by the introduction of the variable speed drives is calculated.