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Thermal Distribution System

The Energy Systems Integration Facility's integrated thermal distribution system consists of a thermal water loop connected to a research boiler and chiller that provide precise and efficient control of the water temperature delivered to laboratories.

Photo of the roof of the Energy Systems Integration Facility.

The thermal distribution bus allows researchers to study and test heating, ventilation, and air conditioning systems as well as combined heat and power applications that require controlled input water temperature or capture waste heat.

The 750,000-Btu-hr condensing-type boiler heats water with high efficiency (> 90% HHV) using the waste heat in flue gases to preheat cold water entering the boiler. The boiler has a modulating gas valve to control the output of the burner to match the load, with a minimum turndown ratio of 10 (allowing operation as low as 10% of its full load level).

The 60-ton chiller cools water with continuous thermal control using hot gas bypass in one stage to divert hot, high-pressure refrigerant vapor from the discharge line directly to the low-pressure side of the system. This allows for variable loads on the evaporator, keeps the compressor more fully loaded, and allows for efficient operation over a range of expected demands for chilled water.