Presevi controller model no. A5-G312PR was retrofitted in the senate room of Indian Institute of Technology Madras, Chennai that had 2 nos. of Carrier 7.5 Tr air conditioner (model no. 38LH09OT) and one no.of 12 Tr of Blustar package air conditioners with one or three phase compressor. These were connected in a common AHU. There was a dampher to control the fresh air intake also.
Temperature of AHU was set at 24 Deg. C performance of the system was studied with 102 occupants. The meeting started at 14.35 Hrs. and ended at 17.50 Hrs. The controller could load / upload the air conditioners and maintain a temperature between 25.1 and 23.9 °C and saved energy.
CO2 level was also monitored and controlled the CO2 level was between 800 & 1400 PPM. On monitoring the energy consumption, it was found that a total of 27.86 units alone was consumed which was a considerable saving when compared with the older method of controlling
The unit is functioning since July 2004 and is working properly.