Patent ID: 8701424

Claim:
A refrigeration system comprising: a plurality of turbo refrigerators cooling a coolant, the plurality of turbo refrigerators including at least a first turbo refrigerator and a second turbo refrigerator; a facility-side control unit that controls a flow rate and the temperature of the coolant; and a coolant supplying unit connected to each of the plurality of turbo refrigerators to receive the coolant from each of the turbo refrigerators to merge the respective received coolant and supply thus merged coolant to an external load, the plurality of turbo refrigerators being connected to the coolant supplying unit in parallel; each of the turbo refrigerators having a rated coolant flow rate and comprising a turbo compressor that compresses a refrigerant, a condenser that condenses the compressed refrigerant, an expansion valve that expands the condensed refrigerant, an evaporator that evaporates the expanded refrigerant and cools a coolant, and a refrigerator-side control unit that controls an operation so that a coolant outlet temperature, which is the temperature of the coolant cooled at the evaporator, is equal to a desired value; wherein a first turbo refrigerator of the plurality of turbo refrigerators is rendered in an early-activation standby mode in which the refrigerator-side control unit receives a target heat load at which the turbo refrigerator operates, wherein a heat load of the turbo refrigerator is a function of a flow rate of the coolant flowing into the evaporator; wherein the refrigerator-side control unit of the first turbo refrigerator receives a current coolant inlet temperature and a target coolant outlet temperature, wherein the current coolant inlet temperature is a current temperature of the coolant flowing into the evaporator of the first turbo refrigerator, and wherein the target coolant outlet temperature is a target temperature of the coolant at the outlet of the evaporator, wherein the refrigerator-side control unit of the first turbo refrigerator determines whether the target heat load is lower than or equal to a predetermined threshold value, and if so, the refrigerator-side control unit calculates a target coolant flow rate of the coolant flowing into the evaporator of the first turbo refrigerator so as to lower the flow rate of the coolant flowing into the evaporator to an amount below the rated coolant flow rate of the first turbo refrigerator, on the basis of the current coolant inlet temperature and the target coolant outlet temperature, such that the target coolant flow rate satisfies the target heat load, while the second turbo refrigerator maintains the rated coolant flow rate, wherein the refrigerator-side control unit in the first turbo refrigerator obtains the target coolant outlet temperature and the target heat load from the facility-side control unit and outputs the target coolant flow rate to the facility-side control unit.