Publication

Abstract : Solution for the energy dilemma “doubled energy demand with half of current carbon emission” lies in successful implementation of energy efficiency projects in vital few loads like Heating Ventilation and Air Conditioning(HVAC) which contributes to more than 30% of the total energy consumed in industries and commercial buildings. Sufficient amount of Air flow by the installed fans with respect to the demand is very much necessary in any Air Handling Units (AHU). As per affinity law, flow in any fan is proportional to speed and Power is proportional to the cube of shaft speed. Speed control of induction motor driven centrifugal fan selected for the required flow and static pressure is the widely used method of energy conservation in any AHU’s. But two important factors determines the amount of energy saved by speed control, which are the efficiency of the motor or the drive and allowed range of efficient speed modulation permitted by the fan design. When compared to Induction Motor (IM), Brush Less Direct Current (BLDC) motors with Electronic Commutation (EC) are more efficient and BLDC EC axial fans can be operated in a wide speed range without much decrease in efficiency. This paper discusses about a case study where an IM driven centrifugal fan in an AHU is retrofitted with BLDC EC motor driven axial fans. The data shows more than 40 % saving in electrical energy which makes the retrofit a techno commercially successful project with a payback of less than 2 years. This high potential energy saving projects lacks popularity due to fewer case studies, fewer suppliers of high capacity BLDC EC fans, non-availability of skilled manpower for retrofit, high initial cost, complex power electronic, harmonics and higher capital cost.