Dubai, UAE, 12 August 2018: Emphasis on air quality, natural lighting and thermal comfort have paved the way for the University of Dubai to be awarded the LEED Gold certification in the New Construction category from the US Green Building Council (USGBC), said Jagath Gunawardena, Senior Manager, Projects and Building Development, Dubai Chamber, which owns the campus. The project brief for the campus was for a sustainable building, which would also help to accelerate and stimulate the academic progress of the students, Gunawardena said.
Speaking on the energy-efficient systems installed across the university, Gunawardena pointed to the chilled water system consisting of three Variable Speed Drive (VSD) driven air-cooled screw chillers. “There are three VSD driven primary chilled water (CHW) pumps connected to a common header,” he said, “such that any CHW pump will be capable of running with any of the three chillers, with pumps sequenced for optimisation algorithms. One of the three chillers named ‘pony chiller’ is half of the capacity of the other two.” The ‘pony chiller’, Gunawardena said, is used during winter and holidays, when demand is low, or “in-between loads” of the larger capacity chillers.
Gunawardena said that almost all the inductive loads in the MEP installation are run on VSD. “The chiller plant manager,” he said, “is designed to minimise the combined electrical energy consumption of operating chillers and pumps, meeting the design chilled water flow and temperature requirements. The water-cooled chiller installed in the fountain pump room acts as a standby to Close Control Units (CCU). As such, the water from the water-feature system is passed through heat exchangers and activates the water-cooled chillers with required flow and temperature and provides chilled water backup to the CCU completing the network.” Essentially, Gunawardena said, the water feature also acts as a cooling tower for the water-cooled chiller. “Occupancy control sensors used for lighting controls,” he said, “are also used to reset the AC VAV terminal to unoccupied mode, thus increasing the room temperature to 27 degrees C, which directly reduces the building thermal load, which helps in reducing the overall energy consumption for air-conditioning system.” Gunawardena, said the HVAC system goes into Free Cooling mode during the winter periods using the controlled fresh air to cool the building interior.
The campus also boasts a sub-metering regimen, and speaking on the sub-metering system, Gunawardena said that proper monitoring of energy and water use is essential. As such, he said, 79 Electrical Energy (kWh) meters, 79 Thermal Energy meters, commonly known as BTU meters, and 11 water meters were installed. He added that the FM team operating the University manages the meters to optimise efficient use of the utilities. Gunawardena added that the HVAC systems are controlled by Johnson Controls BMS with a web-based operator work station and integrated with KNX and BACnet protocol.
Hannah Jo Uy is Assistant Editor at Climate Control Middle East magazine. She may be contacted at firstname.lastname@example.org