US 9,175,889 B2Granted

Heat source system and control method thereof

AssigneeMitsubishi Heavy Industries, Ltd.

InventorKenji Ueda

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Abstract

An object is to provide a heat source system capable of realizing energy saving. In a heat source system including: a chilled-water main control heat pump (1) having a lower-stage evaporator (9) that cools chilled water and a lower-stage condenser (7) that dissipates heat into cooling water, and outputting the chilled water cooled in the lower-stage evaporator (9) to an external load; and a hot-water main control heat pump (51) having a higher-stage evaporator (59) to which heat is provided by medium-temperature water that has been heated with the exhaust heat from the lower-stage condenser (7) and a higher-stage condenser (57) that heats high-temperature water, and outputting the high-temperature water heated in the higher-stage condenser (57) to an external load; a lower temperature limit of the cooling water is set on the basis of a set temperature of the high-temperature water.

Claims10

Dependent claims

A heat source system comprising:

a chilled-water main control heat pump having a lower-stage evaporator that cools chilled water by a vaporization heat of refrigerant and a lower-stage condenser that dissipates a condensation heat of the refrigerant into cooling water, and outputting the chilled water cooled in the lower-stage evaporator to a first external load;
a hot-water main control heat pump having a higher-stage evaporator that evaporates the refrigerant with heat provided from medium-temperature water that has been heated with exhaust heat from the lower-stage condenser and a higher-stage condenser that heats high-temperature water with the condensation heat of the refrigerant, and outputting the high-temperature water heated in the higher-stage condenser to a second external load;
a lower-stage control unit that controls an operation of the chilled-water main control heat pump;
a higher-stage control unit that controls an operation of the hot-water main control heat pump;
a cooling tower that cools the cooling water by sprinkling the cooling water into outside air;
and
a cooling-water-temperature adjusting unit that is provided at the cooling tower and that adjusts a cooling-water temperature,
wherein the lower-stage control unit sets a lower temperature limit of the cooling water on a basis of a set temperature of the high-temperature water that is sent from the high-stage control unit,
wherein, when a percentage of a thermal load of the chilled-water main control heat pump relative to a thermal load of the hot-water main control heat pump is larger than a predetermined value, the lower-stage control unit sends a value of a lower limit of cooling-water temperature is used as a set temperature of the cooling-water to the cooling-water-temperature adjusting unit, and
wherein the cooling-water-temperature adjusting unit is configured to control temperature of the cooling-water circulating in the cooling tower so as to satisfy the lower temperature limit.

7 more elements

A control method of a heat source system that includes

a chilled-water main control heat pump having a lower-stage evaporator that cools chilled water by the vaporization heat of refrigerant and a lower-stage condenser that dissipates the condensation heat of the refrigerant into cooling water, and outputting the chilled water cooled in the lower-stage evaporator to a first external load, and
a hot-water main control heat pump having a higher-stage evaporator that evaporates the refrigerant with the heat given from medium-temperature water that has been heated with the exhaust heat from the lower-stage condenser and a higher-stage condenser that heats high-temperature water with the condensation heat of the refrigerant, and outputting the high-temperature water heated in the higher-stage condenser to a second external load, the control method comprising:
setting a lower temperature limit of the cooling water on the basis of a set temperature of the high-temperature water, and
when a percentage of a thermal load of the chilled-water main control heat pump relative to a thermal load of the hot-water main control heat pump is larger than a predetermined value, setting a lower limit of cooling-water temperature as a set temperature of the cooling-water.

1 more element

Dependencies are inferred from the claim text.