Green building air conditioning system with Variable Frequency Drive and Variable Air flow controller

Abstract

The major consumer of energy in any commercial building or complex is Air conditioning. A novel air conditioning solution has been developed by IIT Madras to reduce the energy consumption in air conditioning. The concept has been piloted and tested for practical viability in IIT Madras Research Park, A 1.2 million square feet R&D building initial results of which are discussed in this paper. Traditionally, in large offices and office space there is problem of either over cooling or under-cooling of specific space. Apart from this, the consumer does not have any direct control over setting the local temperature as per their requirements. As a result, they end up working in an uncomfortable environment. More often than not, in these large offices, large portions are left unoccupied and cooling these zones becomes a waste of energy. In this context, the paper discusses the concept of Variable Frequency Drive (VFD) to drive the air handling unit motors and introduces Variable Air-flow Volume (VAV) unit which helps in cold air balancing by cutting off the air supply in an unoccupied zone. In addition, this paper describes the power consumption scenario of a typical HVAC system and explains how this innovation can bring about 40% power savings in air-distribution as compared to that for the typical systems. This paper also discusses how such a system can be monitored remotely and controlled through an Air-conditioning Management System (AMS), which may be integrated with Building Management System (BMS). Further, the concept of chilling water during the night time when grid-power supply is surplus and storing it in an Insulated Thermal Storage Tank at 6°C, developed by IITM Research Park, is also highlighted in this paper.