Hitachi, Ltd.

Tomio Yoshikawa

Shizuo Zushi

Tetsuji Yamashita

Kyoshiro Murakami

Hiromu Yasuda

Takashi Kato

Kenji Takahashi

Takahiro Daikoku

Takeshi Ito

Hideo Takemoto

Keiji Sato

Kazuo Yoshioka

A cooling apparatus has a heat exchanger for performing heat exchange between cooling water and fluid, and a flow rate regulator valve for regulating a flow rate of either the cooling water or the fluid which pass through the heat exchanger. A cooling temperature of the fluid is preset. A temperature of the cooled fluid is detected, and an opening degree of the flow rate regulator valve is changed when there is a difference between the detected temperature and the preset temperature. Simultaneously, either a temperature difference of the cooling water and the fluid or a flow rate of the cooling water is detected. The opening degree of the flow rate regulator valve is corrected or compensated on the basis of a result of the detection, thus enabling suitable temperature control of the fluid in accordance with a variation of the temperature or flow rate of the cooling water.

Cooling apparatus and temperature control method therefor

There is disclosed a control system for controlling a refrigerating apparatus in which a control unit is arranged to calculate a super heat amount of a discharge gas of a compressor at the time immediately before starting operation of the compressor, on the basis of a difference between temperatures detected by a discharge gas temperature sensor and a condenser temperature sensor and to control an opening degree of an electronic expansion valve to a completely open state. After starting operation of the compressor, the control unit constantly measures the super heat amount of the discharge gas and controls the valve opening degree to the usual degree when the super heat amount becomes higher than the preset value.

Control system for refrigerating apparatus

A control system for controlling cooling equipment comprising a refrigerant circuit for cooling water by heat exchange, a plurality of cooling modules in a backup relationship with an adjusting apparatus for adjusting the cooling capability of the refrigerant circuit and a controller controlling the adjusting apparatus for adjusting the cooling capability, a control module having a coolant temperature sensor and a controller for calculating a cooling capability control command based on the value detected by the coolant temperature sensor. The controller in one of the cooling modules controls the adjusting apparatus and on the cooling capability control commend transmitted from the controller in the control module. Each of the cooling modules has a coolant temperature sensor for detecting the same coolant temperature as detected by the coolant temperature sensor of the control module so that, when an abnormality occurs in the coolant temperature sensor in the control module, the controller in the control module calculates the cooling capability control command based on the value detected by the coolant temperature sensor in the cooling module. The control system is therefore capable of performing a backup operation effective for the occurrence of an abnormality in the control module.

System for controlling cooling equipment

A water chilling apparatus comprising a plurality of chilling modules each having a refrigerating cycle mainly composed of a compressor, a condensor, an evaporator and an expansion mechanism, and a control module having a water pump for feeding, to an object to be chilled, chilling water cooled down by the evaporator of each chilling module, a detector for detecting a temperature of the chilling water and a water temperature controller. A chilling ability of each chilling module in response to a variable frequency is kept at substantially the same level. A capacity of the compressor of each chilling module is variably controlled in a range between an upper limit capacity and a lower limit capacity. The water temperature controller is used to calculate a whole necessary capacity value needed in the compressors of all the chilling modules as a function as a deviation between a set value of the chilling water temperature and a chilling water temperature detected by the detector. The number of the operated chilling modules is controlled in response to the whole necessary capacity value and the upper and lower capacities of each of the chilling modules. The capacity of the compressor of each of the cooling modules is controlled so as to have a capacity value obtained by equally distributing the calculated whole necessary capacity value by the number of the operated chilling modules.

Water chilling method and apparatus for the same

A heating portion is cooled by a fluid, thereby effecting a temperature control. The temperature of the fluid is measured at the time of starting of a system, and the measured fluid temperature is compared with a set temperature. In accordance with the result of the comparison, the timing of starting the operation of LSI chips and the timing of starting the operation of a refrigerator are controlled.

Fluid temperature control system and computer system using same

A refrigerating apparatus has a refrigerating cycle including an electromotive compressor whose operational speed is variable in accordance with a drive frequency, and a control unit for operating the compressor at a frequency correspondent to a load so as to control the operation of the refrigerating cycle. Control of the operational frequency of the compressor by the control unit is effected on the basis of target super heat amounts of a discharged gas which is predetermined over an operational frequency range of the compressor. The target super heat amounts are set such that within a lower region of the operational frequency range, each target amount is larger than a super heat amount at which the maximum refrigeration capability is obtained at each operational frequency, so as to suppress a suction pressure of the compressor within an allowable limit for the compressor.

Refrigerating apparatus

In an air conditioner separated into an indoor unit and an outdoor unit, a control circuit comprises a three-phase power source connected in common to the indoor and outdoor units, and a signal line led out from two phases of the power source. A contact of an electromagnetic relay energizing a compressor of the air conditioner is connected on the portion of the signal line in the indoor unit in series with a current sensor sensing the current flowing through the signal line, and a contact of a protective relay protecting the compressor is connected on the portion of the signal line in the outdoor unit in series with the electromagnetic relay. A first controller is disposed in the indoor unit for controlling on-off of the relay contact of the electromagnetic relay, and a second controller is disposed in the outdoor unit for energizing the protective relay contact thereby controlling on-off of the compressor.

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Shimizu, Japan

Tomio Yoshikawa