Hvac Systems Commissioning In A Manufacturing Plant

As one of the most cost-effective ways to improve energy efficiency, commissioning plays an important role in achieving building energy savings goals. In this paper, a specific case study of energy saving-aimed commissioning was implemented in an existing building by using the methods of retrofitting and optimizing system control and operation. The case study site is a manufacturing plant with a gross area of 1,212,940 sq. ft. (112,685 sq. meters). The work scope of the case study covered the chilled water system with four 1200 ton (4,219 kW) chillers, heating system with two 70,000 lb/hr (31,751kg/hr) steam boilers, and thirty-four air handling units. After a detailed walk-through of the plant, a series of system energy saving opportunities were identified for the existing system operation such as chilled water bypassing the building, blending of supply and return chilled water, high oxygen level in flue gas of the boiler, and extra fan power consumption for constant air volume systems and the like. After system retrofits and implementation of advanced control strategy, system overall performance was greatly improved. The compared utility data before and after the system optimization indicate a total annual saving of $508,558 with the total electricity consumption reduced by 15% and total gas consumption reduced by 7%, considering the economic impact. In the paper, the system information, major retrofits, and advanced control sequences and operational data were introduced and discussed.