JPS6225643Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a cooling system, more specifically, it is equipped with a plurality of compressors, the condenser is an air heat exchanger that exchanges heat with outside air, and the compressor is turned on and off depending on the cooling load to increase the capacity. The present invention relates to a cooling device that is controlled.

Conventionally, this type of equipment controls capacity by starting and stopping multiple compressors depending on the cooling load, but when performing capacity control in this way, a large amount of starting current is generated each time the compressor motor is started. There was a problem in that the power consumption increased unnecessarily.

Therefore, when air conditioning is performed all year round, day and night, regardless of the season, such as in a building with a computer room, the wasted power consumption due to the starting current is accumulated, and the ratio of annual cooling capacity per annual supply power, so-called There was a problem where SEER decreased.

Therefore, in order to solve the problem of capacity control by starting and stopping the compressor as described above, a capacity control mechanism is provided in the compressor, and the capacity control mechanism operates without depending on starting and stopping the compressor. Therefore, it is conceivable to control the capacity, but in this way, when performing cooling operation by controlling the capacity when the outside air temperature is low, such as in winter, the cooling capacity of the outside air in the condenser becomes excessive and the high pressure decreases. Moreover, there is a problem that the lower the capacity of the compressor is controlled, the greater the drop in high pressure becomes, making it impossible to operate. By the way, as a countermeasure to this problem, the amount of heat radiated from the condenser can be reduced by, for example, installing multiple fans attached to the condenser, reducing the number of fans in operation, or slowing down the rotational speed of the fans. is possible, but
It is difficult to accurately match the compressor capacity and the heat dissipation amount in the condenser, especially at 25% capacity or
When controlling a low capacity such as 50% capacity, a sufficiently high pressure increase cannot be obtained, and the problem of the high pressure drop described above cannot be fundamentally solved.

By the way, when the compressor is operating at 100% capacity, when the outside temperature is 7.2℃ and the high pressure value is 9.5Kg/ ^cm2 , if the condenser air volume is halved, the high pressure value will be 14Kg/ ^cm2.
However, when the compressor is operated at 25% capacity, the high pressure value is 6.8 kg/
cm ² , the high pressure value remains even if the condenser air volume is halved.
The pressure is only 8.0Kg/cm ² , and a sufficiently high pressure increase cannot be obtained.

The present invention was devised in view of the above problems, and its purpose is to be able to maintain high pressure above a predetermined value, regardless of the controlled capacity of the compressor, even when the outside temperature is low, such as in winter. Another object of the present invention is to provide a cooling device that can also increase the ratio of annual capacity to annual power supply (SEER).

That is, the present invention connects a plurality of air-cooled condensers that exchange heat with outside air to each of a plurality of compressors to form a refrigerant circuit, and connects a plurality of systems to an evaporator to form a refrigerant circuit. In the cooling device, each compressor is configured to be capable of partial capacity control and start/stop control, and a load detector for detecting the cooling load and an outside temperature detector for detecting outside air temperature are provided. When the outside air temperature detected by the outside air temperature detector is higher than the set temperature, the load detector controls the partial capacity of each compressor, and when the outside air temperature detected by the outside air temperature detector is lower than the set temperature, the load detector The present invention is characterized in that a control circuit is provided to control the start and stop of each of the compressors.

Embodiments of the device of the present invention will be described below based on the drawings.

The system shown in Fig. 1 cools a cooling area A consisting of multiple rooms a ₁ , a ₂ , a _{3 .} . . such as a computer room a 1 formed in a building _B. The computer room _A1 has a room that generates a cooling load all year round, not only in the summer and intermediate seasons, but also in the winter, in other words, day and night.

In FIG. 1, 1 and 2 are eight-cylinder compressors each having a pair of two cylinders, and 3,
4 is an air-cooled condenser consisting of an air heat exchanger that exchanges heat with outside air, and the condenser 3 includes four motors M ₁ ,
Four outdoor fans F _{1 ,} F ₂ , F ₃ , F ₄ driven by M 2 , M ₃ , M ₄ are installed in opposition, and the condenser 4 also has four motors M ₅ , M _{6 .} , M ₇ , and M ₈ , four outdoor fans F ₅ , F ₆ , F ₇ , and F ₈ are arranged opposite to each other.

5 and 6 are expansion valves, and 7 is a water evaporator provided with two systems of refrigerant pipes.A water inlet pipe 8 and a water outlet pipe 9 are connected to the evaporator 7.

The compressor 1, condenser 3, expansion valve 5,
One system of refrigerant pipes of the evaporator 7 is connected to the refrigerant pipe 10, and the compressor 2, the condenser 4, the expansion valve 6,
The other refrigerant pipes of the evaporator 7 are connected by refrigerant pipes 11 to form two refrigerating circuits. Further, the water inlet pipe 8 and water outlet pipe 9 of the evaporator 7 are connected to each room a ₁ , a ₂ ,
It is connected to the cooling coils c ₁ , c ₂ , c ₃ . . _. installed in a 3 . . . to form a chilled water circuit.

A load detector th ₁ is provided to detect the water temperature in the water inlet pipe 8 returning from the cooling area A to the evaporator 7 in the chilled water circuit, that is, the cooling load.
By the operation of th ₁ , the compressors 1 and 2 are started and stopped according to the cooling load to control the capacity. That is, when the water temperature is lower than the first set value, the overall capacity of both compressors 1 and 2 is reduced.
When the water temperature is equal to or higher than the first set value and lower than the second set value, one of the compressors 1 and 2 is stopped and the other one is operated. % capacity, and when the water temperature is equal to or higher than a second set value, the capacity is controlled to 100% capacity where both compressors 1 and 2 are operated.

Further, each of the compressors 1 and 2 is provided with a capacity control mechanism 13 and 14, respectively, so that the capacity is controlled by the operation of the detector _th1 that detects the cooling load. It is possible to switch between capacity control by starting and stopping the compressors 1 and ₂ , and capacity control by operating the capacity control mechanisms 13 and 14. A detector th ₂ is provided, and when the outside air temperature detected by the outside air temperature detector th ₂ is higher than the set temperature, the capacity control mechanism 13 of each of the compressors 1 and 2 is activated by the detector _th 1. , 14 to control the capacity,
In addition, when the outside temperature is low, the detector th ₁
This is done by switching the compressors 1 and 2 on and off to control the capacity.

Capacity control mechanisms 13 and 14 for each of the compressors 1 and 2
are unloading solenoid valves SV ₁ , so that each of the three sets out of the four sets of two cylinders in each compressor 1 and 2 can be individually unloaded.
SV ₂ , SV ₃ , SV ₄ , SV ₅ , and SV ₆ are provided, and each of the electromagnetic valves SV ₁ to _{SV 6} is activated by the operation of the detector th ₁ .
The capacity of compressors 1 and 2 is controlled to open and close to 25% capacity, 50% capacity, 75% capacity and 100% capacity depending on the cooling load.
This is done to control the capacity to % capacity. Specifically, the capacity of each compressor 1, 2 is determined by the solenoid valves SV ₁ , SV ₂ ,
When SV ₃ , SV ₄ , SV ₅ , and SV ₆ are all energized to 25% capacity, and when the water temperature is higher than the second set value and lower than the third set value, for example, 14°C, the solenoid valves SV ₁ ,
Only SV ₄ is demagnetized to 50% capacity, and when the water temperature is higher than the third set value and lower than the fourth set value, for example 15°C, solenoid valves SV ₁ , SV ₂ , SV ₄ , and SV ₅ are demagnetized. When the water temperature is equal to or higher than the fourth set value, the solenoid valves SV ₁ , SV ₂ , SV ₃ , SV ₄ ,
Both SV ₅ and SV ₆ are demagnetized to 100% capacity, and each capacity is controlled.

The set temperature of the detector th ₂ that detects the outside air temperature is, for example, 10°C.
is set to 50% and 25% when the cooling load decreases and the capacity of the compressors 1 and 2 is set to 50% and 25%, respectively, when the cooling operation is performed by capacity control by the operation of the capacity control mechanisms 13 and 14.
This is because the high pressure value of the refrigeration circuit can be maintained at a predetermined pressure value or higher even when the pressure is controlled to be small.

Next, an electric circuit for switching between the two capacity controls described above will be explained with reference to FIG. 2.

That is, between the two power supply lines, there is a series circuit of the outside temperature detector th ₂ and the auxiliary relay R ₉ , and a normally open terminal of the motor relay RC ₂ and relay R ₆ of the compressor 2.
_R6 -a series circuit and compressor 1 motor relay
A circuit in which normally open terminal R _{2 -a of relay R 2 is connected} in series is connected to the parallel circuit with RC 1, and the unloading solenoid valve is connected to the cooling load detector th ₁ .
SV ₁ ...SV ₆ and the 8 outdoor fans F ₁ ...F ₈
Motor M ₁ ... Relay for M ₈ R ₁ , R ₂ , R ₃ , R ₄ ,
The circuit connecting R ₅ , R ₆ , R ₇ , and R ₈ is connected.

The detector th ₁ detects the first, second, third, and third of the water temperature.
It is equipped with switches S ₁ , S ₂ , S ₃ , and S ₄ that operate at four set values, and the relay is connected to the high temperature side terminal H ₁ of the switch S ₁ .
Connect the parallel circuits of R ₁ , R ₂ , R ₃ , R ₄ and
The above-mentioned relays R ₅ , R 6 , R ₇ are connected to the high-temperature side terminals H ₁ , H ₂ of switches S ₁ , S ₂ via normally open contacts R _{9 -a} and normally closed contacts R ₉ -b of auxiliary relay R ₉ . _{, R8} are connected _in parallel _, and _the solenoid valves _{SV1 , SV4 ,}
Connect each parallel circuit of SV ₂ , SV ₅ , SV ₃ , SV ₆ ,
The normally open terminal R ₉ -a of the auxiliary relay R ₉ is connected in series to the solenoid valves SV ₁ ...SV ₆ of each of the parallel circuits.

Note that HPS ₁ and HPS ₂ are high pressure switches.

However, in the above configuration, when performing cooling operation in the cooling area A when the outside air temperature is higher than the set temperature of the detector th ₂ , such as in the summer or mid-season, the closing operation of the detector th ₂ provides assistance. relay
_R9 is energized, and the normally open terminal _R9 is connected in series to the solenoid valves _SV1 ... _SV6 of each capacity control mechanism 13, 14.
-a is held closed.

Thus, when the water temperature is equal to or higher than the fourth set value (15°C), each switch S ₁ ... S ₄ of the detector th ₁ is activated.
are all switched to the high temperature side, and the relays R ₁ ... R ₈ are energized via the switches S ₁ and S ₂ , and the motors M ₁ ... M ₈ are driven to drive the fans F ₁ ...
... _F8 is activated, and relays _{RC1 and RC2 are energized by the excitation of relays R2 and R6 ,} and the compressors 1 and ₂ are energized.
2 are operated together.

Then, the electromagnetic valves SV ₁ ...SV ₆ of the capacity control mechanisms 13 and 14 are all demagnetized, and the compressors 1 and 2 are both operated at full capacity.
The overall capacity is controlled to 100% capacity.

Further, the water temperature is lower than the fourth set value and the third set value is lower than the fourth set value.
When the set value is 14°C or higher, among the switches S ₁ ... S ₄ of detector th ₁ , only switch S ₄ is connected to the low temperature side terminal L ₄
As a result, only the solenoid valves SV ₃ and SV ₆ of the capacity control mechanisms 13 and 14 are energized, and the compressors 1 and 1 are energized.
The overall capacity of 2 is controlled to 75% capacity.

Further, the water temperature is lower than the third set value and the second set value is lower than the third set value.
When the temperature is above the set value (13°C), switches S 4 _{and S 3} of the switches S ₁ ... S ₄ of the detector th ₁ switch to the low temperature side terminals L ₄ and _{L 3 to} control the capacity. Only the electromagnetic valves SV ₃ , SV ₂ , SV ⁶ , and SV ₅ of the mechanisms 13 and 14 are excited, and the overall capacity of the compressors 1 and 2 is controlled to 50% capacity.

Further, the water temperature is lower than the second set value and the first set value is lower than the second set value.
When the temperature is above the set value (12℃), switches S ₄ , S ₃ , and S ₂ of each switch S ₁ ... S ₄ of detector th ₁ switch to low temperature side terminals L ₄ , L ₃ , and L _2. Then, each of the relays _R1 ... _R8 is energized via the switch _S1 . Thus, each fan F ₁ ... F ₈ and compressor 1,
The solenoid valves SV ₃ , SV ₂ , and
SV ₁ , SV ₆ , SV ₅ , and SV ₄ are all excited, and the overall capacity of the compressors 1 and 2 is controlled to 25% capacity.

When the capacity of the compressors 1 and 2 is controlled as described above, if the high pressure of the refrigeration circuit drops below the specified pressure value, the high pressure switches HPS ₁ and HPS ₂ are opened, and each of the four compressors Of the fans _F1 ... _F4 , _F5 ... _F8 , the fans _F3 , _F4 , _F7 , _F8 for each two units stopped, and the condensing capacity of each condenser 3 and 4 was reduced by half. , the high pressure value is restored above the predetermined pressure value.

Further, when the water temperature becomes lower than the first set value, each switch _S1 ... _S4 of each detector _th1 is switched to the low temperature side terminal _L4 , _L3 , _L2 , _L1 , Each of the relays R ₁ ...R ₈ is demagnetized and each fan F ₁ ...
When F ₈ is stopped, both compressors 1 and 2 are stopped.

Next, in a state where the outside air temperature has become lower than the set temperature of the detector th ₂ from the intermediate season to the winter season, when performing cooling operation of a room that requires cooling, such as the computer room a ₁ of the cooling area A, the above-mentioned Due to the opening operation of the detector _th2 , the auxiliary relay _R9 is demagnetized, and each capacity control mechanism 13, 14 operates each solenoid valve _SV1 ...
Both SVs ₆ are kept de-energized at all times.

Thus, when the water temperature is equal to or higher than the second set value (13°C), the relays _R1 ... _R8 are energized via the switches _S1 , _S2 of the detector _th1 , and each motor is energized.
M ₁ ...M ₈ is driven and each fan F ₁ ... F ₈ is activated, and relays R ₂ and R ₆ are energized to activate the relays.
RC ₁ and RC ₂ are excited, and the capacity is controlled to 100% capacity where both compressors 1 and 2 are operated.

Furthermore, when the water temperature is lower than the second set value and higher than the first set value (12°C), the high temperature side terminal _H2 of the switch _S2 is opened, relays _R5 ... _R8 are demagnetized, and each fan is demagnetized. F ₅ ... When F ₈ stops, compressor 2
stops, while the high temperature side terminal _H2 of switch _S1 closes, relays _R1 ... _R4 are energized, and each fan _F1 ...
50% when F ₄ is driven and only compressor 1 is driven
Capacity is controlled by capacity.

Further, when the water temperature is lower than the first set value, the high voltage side terminals H ₁ and H ₂ of the switches S ₁ and S ₂ are opened, each relay R ₁ ... R ₈ is demagnetized, and each fan F ₁ ...When F ₈ is stopped, both compressors 1 and 2 are stopped, and the capacity is controlled to 0% capacity.

As described above, until the outside air temperature drops to the set temperature, the capacity control mechanism 1 for each of the compressors 1 and 2
Since capacity control is performed by the operation of compressors 3 and 14, the number of times that the motors of compressors 1 and 2 are started can be reduced significantly, and unnecessary increases in power consumption due to large starting currents can be almost completely eliminated. Moreover, when the outside air temperature drops below the set temperature, capacity control is switched to starting and stopping compressors 1 and 2, so that even if the cooling load is small, the high pressure can be prevented from dropping below a predetermined value. Cooling of cooling area A can be performed stably all year round, while the SEER value can be sufficiently improved.

In the above explanation, the compressors 1 and 2 are of the 8-cylinder type, but it is of course possible to use a multi-cylinder type other than the 8-cylinder type, and the compressors are not limited to the multi-cylinder type.
For each of the compressors 1 and 2, it is possible to use various types of compressors whose capacity can be controlled without depending on whether they are turned on or off, such as one in which the number of poles of the compressor motor is changed. When using such various types, the capacity control mechanism 1
It goes without saying that 3 and 14 correspond to the compressor used.

Further, in the above description, two compressors are used, but three or more compressors may be used.

Further, the cooling load detector th ₁ is the evaporator 7
Although the water temperature in the water inlet pipe 8 is to be detected, the water temperature is not limited to the above water temperature. For example, the water temperature in the water outlet pipe 9 is detected.
It may be the internal water temperature.

Further, although the evaporator 7 is used for water, it may be used for air, and a duct may be used to form a cooling air passage between the evaporator and the cooling area A.

As described above, the present invention has a plurality of compressors 1 and 2.
A plurality of systems are formed by connecting air-cooled condensers 3 and 4 for heat exchange with outside air to each of the evaporators 7 and 7.
In the cooling system in which the evaporator 7 is connected to form a refrigerant circuit and a cooling load is connected to the evaporator 7, each of the compressors 1 and 2 is configured to be capable of partial capacity control and start/stop control, and the cooling load is _The load detector th ₁ detects the outside air temperature _, and the outside air temperature sensor th ₂ detects the outside air temperature. A control circuit is provided so that partial capacity control of compressors 1 and _{2 is performed, and when the outside air temperature detected by outside air temperature detector th 2} is lower than the set temperature, the load detector th ₁ controls the start/stop of each of the compressors 1 and 2. Therefore, until the outside air temperature drops to the set temperature, the capacity control mechanisms 13 and 14 for each compressor 1 and 2 are activated.
Capacity control can be performed by the operation of By switching to capacity control by starting and stopping each compressor 1 and 2, it is possible to prevent the high pressure from falling below the specified pressure value even when the cooling load is small, and to ensure stable cooling operation throughout the year regardless of the cooling load. While doing so, it is possible to sufficiently improve the SEER value.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of refrigerant piping and cold water piping showing an embodiment of the present invention, and FIG. 2 is an electric circuit diagram. 1, 2... Compressor, 3, 4... Condenser, 13, 14
… Capacity control mechanism, th ₁ … load detector, th ₂ … outside air temperature detector.

Claims (1)

[Scope of utility model registration request] A plurality of systems are formed by connecting air-cooled condensers 3 and 4 that exchange heat with outside air to each of the plurality of compressors 1 and 2, respectively, and are connected to the evaporator 7 to form a refrigerant circuit. In the cooling device in which a cooling load is connected to the cooling device 7, each of the compressors 1 and 2 is configured to be capable of partial capacity control and on/off control, and a load detector _TH1 detects the cooling load and detects outside air temperature. When the outside air temperature detected by the outside air temperature sensor _{th 2 is} higher than the set temperature, the load detector th ₁ sets the compressor 1,
2 is provided in a control circuit such that partial capacity control is performed on the compressors _{1 and 2, and when the outside air temperature detected by the outside air temperature detector th 2} is lower than the set temperature, the load detector th ₁ controls the start/stop of each of the compressors 1 and 2. A cooling device featuring: