CPC F24F 3/065 (2013.01) [F24F 11/65 (2018.01); F24F 11/85 (2018.01); F25B 25/005 (2013.01); F25B 49/022 (2013.01); F25B 49/027 (2013.01); F28F 27/003 (2013.01); F25B 2339/047 (2013.01); Y02B 30/54 (2013.01)] | 16 Claims |
1. A method of operating a chiller system, comprising:
operating the chiller system in a free cooling mode, wherein a cooling load process fluid exchanges heat with a cooling tower at a heat exchanger and the cooling load process fluid bypasses a mechanical cooling circuit;
during operation in the free cooling mode, determining that a leaving temperature of the cooling load process fluid from the heat exchanger is outside a range of permissible temperatures;
following determination that the leaving temperature of the cooling load process fluid from the heat exchanger is outside the range of permissible temperatures, determining an operation mode, wherein:
the operation mode is one of a mechanical cooling mode where the cooling load process fluid exchanges heat with the mechanical cooling circuit and bypasses the heat exchanger or an integrated free cooling mode where the cooling load process fluid exchanges heat with the mechanical cooling circuit and exchanges heat with the cooling tower at the heat exchanger,
the operation mode is determined from an ability of the cooling tower to contribute to cooling of the cooling load process fluid; and
operating the chiller system in the determined operation mode
wherein the ability of the cooling tower to contribute to cooling of the cooling load process fluid is determined based on at least one of an output of a cooling tower model, an output of a heat exchanger model, and an output of a pump model.
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