Integrated Chiller System Reduce Building Operation and Maintenance Costs in Cold Climates

Although water-cooled chillers are more energy\nefficient than air-cooled chillers, a majority of chilled\nwater systems use air-cooled chillers. In cold\nweather climates, air-cooled chillers are capable of\nfunctioning in low ambient temperatures with few\noperational concerns, where as water-cooled chiller\nsystems must be equipped to prevent cooling tower\nfreezing. The integrated chiller system attempts to\ntake advantage of each chiller's strengths and\neliminate any cold weather operational concerns. An\nintegrated chiller system includes a cooling tower and\nair-cooled condenser. During the summer, both the\ncooling tower and air condenser can be operated. In\ncold weather, the cooling tower is drained and the air\ncondenser is used to dissipate the heat of the cooling\nsystem. The integrated chiller system eliminates the\nwater storage tank and frequent charging and\ndischarging of the cooling tower system. It reduces\nthe size of the mechanical room and simplifies the\noperation of the system. The integrated chiller system\nis most suitable in climates where the mechanical\ncooling is required on a short-term basis during cold\nweather periods. This paper presents the system\nconfiguration, system design, optimal control, and\nenergy impact. An example is used to demonstrate\nthe design concepts of the integrated chiller systems.