JPH0926223A - Absorption type cold heat generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable smoothly starting the cooling operation which is proportionate to the load factor by a method wherein when the cooling-water temperature outputted by a temperature sensor at the inlet for the cooling water is below a second temperature set lower than a first temperature, a water-refrigerant proportional valve is opened fully independent of the temperature of an evaporator. SOLUTION: A cooling water-inlet-temperature sensor 25 is provided in the vicinity of the joint between a cooling-water pipe 41 and an absorber 5 and, while the opening of a water-refrigerant proportional valve 11 is controlled without steps on the basis of the output of an evaporator-temperature sensor 17 and also on the basis of the cooling water-inlet-temperature outputted by the cooling water-inlet-temperature sensor 25. A controller 59 controls the opening of the water-refrigerant proportional valve 11 on the basis of the output of the evaporator-temperature sensor 17 and that of the cooling water-inlet-temperature sensor 25 and make the rise part at the outlet of an evaporator coil in the refrigerant-vapor pipe 51 and the connecting part of the evaporator coil in the liquid-refrigerant pipe 50 communicate through a solenoid valve 60. The water-refrigerant proportional valve 11 keeps fully closed when the cooling water-inlet-temperature is, for example, 6 deg.C or higher and fully open when the temperature is, for example, 2 deg.C or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption type cold heat generating device, and more particularly to an absorption type cold heat generating device using a fluid utilizing a phase change as a secondary refrigerant.

[0002]

2. Description of the Related Art Conventionally, as an absorption type cold heat generator, an air conditioner using an absorption chiller / heater having a structure shown in FIG. 4 has been known. The illustrated apparatus is an absorption chiller-heater 100 that generates cold heat.
A cooling tower 42 connected to the absorption chiller / heater 100 by cooling water pipes 40, 41 to cool the cooling water; and a cooling tower 42 connected to the absorption chiller / heater 100 by cold / hot water pipes 43, 44 and arranged in an air-conditioned space. An air conditioning indoor unit (not shown) for exchanging heat with air, and absorption of cooling water from the cooling tower 42 interposed in the cooling water pipe 41 into the chiller / heater 1
Cooling water circulation pump 14 for circulating to 00, and cold / hot water circulation for circulating the secondary refrigerant interposed in the cold / hot water pipe 43 and filled in the cold / hot water pipes 43, 44 between the absorption cold / hot water machine 100 and the indoor unit for air conditioning. The pump 15 is included.

In contrast to the above-mentioned air conditioner indoor unit, an absorption chiller-heater 100, which is usually called an outdoor unit together with the cooling tower 42, has a high temperature regenerator 1 for burning fuel and heating the dilute solution with its heat, and this high temperature regenerator. A separator 2 for separating a refrigerant vapor and an intermediate concentrated solution from a dilute solution heated by a regenerator 1, and a low temperature regenerator 3 for heating the intermediate concentrated solution by using the separated refrigerant vapor as a heat source to further generate a refrigerant vapor. A condenser 4 that cools and condenses and liquefies the refrigerant vapor that has passed through the low-temperature regenerator 3 and the refrigerant vapor that has occurred in the low-temperature regenerator 3 to produce a liquid refrigerant; and the liquid refrigerant that has generated in the condenser 4. An evaporator 6 for cooling the secondary refrigerant in the evaporation coil by dropping and evaporating it from the refrigerant distributor 6B in which the same is installed,
The absorber 5 which absorbs the refrigerant vapor evaporated in the evaporator 6 into a concentrated solution to produce a dilute solution, and the low-temperature solution heat exchanger 8 and the high-temperature solution heat exchanger 7 to be heated are connected to the heated fluid side by pressurizing the dilute solution. The solution circulating pump 9 that is sent to the high temperature regenerator 1 via the above, the pipe 10A that connects the bottom of the separator 2 and the bottom of the evaporator 6 via a cooling / heating switching valve 10, and the low temperature solution heat exchanger 8
A concentrated solution pipe 8A connecting the heated fluid outlet side to the upper part of the absorber 5, a conduit 13A connecting the concentrated solution pipe 8A and the lower part of the absorber 5 via a solution bypass valve 13, and A pipe line 12A that connects the solution pipe 8A and a refrigerant distributor installed in the evaporator 5 via an antifreezing valve 12, and evaporation that is attached to the refrigerant distributor and detects the temperature of the refrigerant in the refrigerant distributor. A temperature sensor 17, a water refrigerant pipe 11B for guiding a liquid refrigerant from the condenser 4 to the refrigerant distributor 6B, and a pipe line 11A connected in parallel to the water refrigerant pipe 11B and having a water refrigerant proportional valve 11 interposed therebetween. , Is included.

Further, the intermediate concentrated solution separated by the separator 2 is introduced into the low temperature regenerator 3 via the heating fluid side of the high temperature solution heat exchanger 7, and the refrigerant is evaporated in the low temperature regenerator 3 to form a concentrated solution. After that, the pipe line is configured to be guided to the concentrated solution pipe 8A through the heating fluid side of the low temperature solution heat exchanger 8. A cooling water coil is installed in each of the absorber 5 and the condenser 4, and an outlet of the cooling water coil of the absorber 5 is connected to an inlet of the cooling water coil of the condenser 4 to cool the cooling water of the absorber 5. The inlet of the coil is the cooling water pipe 4
1, the outlet of the cooling water coil of the condenser 4 is the cooling water pipe 4
0, respectively. The cold / hot water pipe 43 is provided on the inlet side of the evaporator coil of the evaporator 6 at the cold / hot water pipe 44.
Is connected to the outlet side of the evaporator coil of the evaporator 6, and a cold water outlet temperature sensor 16 for detecting the temperature of the secondary refrigerant is mounted in the vicinity of the evaporator coil outlet of the cold / hot water pipe 44.

In the apparatus having the above structure, the cooling / heating switching valve 10
Switches between cooling and heating, and is closed during cooling and open during heating. The water-refrigerant proportional valve 11 is a valve whose opening is controlled by inputting the temperature of the evaporator (output of the evaporator temperature sensor 17) to adjust the solution concentration. Antifreeze valve 12
Is opened when the evaporation temperature decreases to 1 ° C. and the concentrated solution is caused to flow into the refrigerant distributor 6B, and the refrigerant (usually water is used as the refrigerant of the absorption chiller-heater. Hereinafter, also referred to as water refrigerant). This is a valve that prevents freezing. The solution bypass valve 13 bypasses the concentrated solution to the lower part of the absorber 5 to lower the absorption capacity of the absorber 5 before the antifreezing valve is activated when the evaporator temperature is lowered during cooling start-up and low load operation. It is an on-off control valve for lowering and preventing further temperature drop of the evaporator.

The absorption chiller-heater suffers the most damage from the fact that the water refrigerant in the machine freezes during the cooling operation and is crystallized, and the cold-hot water circuit freezes and breaks when the load is low. In order to prevent these situations, various protection controls based on the cold / hot water outlet temperature and the evaporator temperature are performed.

For example, in the case where cold water at 7 ° C. is taken out at 100% load, the cold water temperature lowers as much as the capacity exceeds the load when the load is small. Normally, when the cold water outlet temperature reaches 5 to 6 ° C, the combustion of the high temperature regenerator 1 is stopped. When the air conditioner starts up or when the load is low, the evaporator temperature may drop below the chilled water outlet temperature by more than an appropriate temperature range.Therefore, the evaporator temperature should be adjusted so that the water refrigerant inside the machine does not freeze and crystallize. Based on this, various protection controls are performed.

FIG. 3 shows an example of control based on the evaporator temperature. In the figure, LT0 to LT2 indicate control types of evaporator temperature control. LT0: The solution bypass valve 13 is opened when the evaporator temperature drops to 2 ° C., and the solution bypass valve 13 is closed when the evaporator temperature rises to 3 ° C. LT1: Antifreeze valve 12 when the evaporator temperature drops to 1 ° C
Freeze valve 12 when the evaporator temperature rises to 2 ℃
Close. LT2: High temperature regenerator 1 when the evaporator temperature drops to -2 ° C
Combustion is stopped and the cooling water circulation pump 14 is stopped. When the evaporator temperature rises to -1 ° C, combustion in the high temperature regenerator 1 is started and the cooling water circulation pump 14 is started.

[0009]

In the air conditioner shown in FIG. 4, a fluid that does not change phase, generally a liquid, has been used as the secondary refrigerant that circulates between the indoor unit and the outdoor unit to transfer heat. However, in recent years, it has been devised to increase the amount of heat transfer per unit flow rate by causing a phase change in the secondary refrigerant. FIG. 5 shows an example of such a configuration. In the configuration shown in FIG. 4, instead of the cold / hot water pipes 43 and 44, a refrigerant liquid pipe 50 and a refrigerant vapor pipe 51 are the lower end of the evaporation coil.
Each is connected to the upper end. The other ends of the refrigerant liquid pipe 50 and the refrigerant vapor pipe 51 are branched by the number of the indoor units 52 and 53 arranged below the evaporation coil.
The branch ends of the refrigerant vapor pipes 51 are connected to the lower inlets of the heat exchangers respectively installed in the indoor units via expansion valves 54 and 55, and are connected to the upper inlets of the heat exchangers, respectively. Has been done. A refrigerant liquid temperature sensor 21 that detects the temperature of the secondary refrigerant and outputs it as an electric signal to the controller 59 is mounted near the connection portion of the refrigerant liquid pipe 50 with the evaporation coil.

The refrigerant liquid pipe 50 is connected to the indoor units 52 and 53 on the way.
There is a portion arranged at a lower position than the above, and a refrigerant pump 57 that pressurizes the refrigerant liquid and sends it to the evaporation coil is attached thereto. A check valve 58 is provided on the discharge side of the refrigerant pump 57, and the outlet side of the check valve 58 and the refrigerant pump 5 are provided.
The suction side of 7 is connected via a cooling / heating switching valve 56. A refrigerant liquid pipe is filled with HFC-134a as a secondary refrigerant (hereinafter, also simply referred to as a refrigerant) that undergoes a phase change.
Since the other configurations are the same as those described with reference to FIG. 4, description thereof will be omitted.

The operation of the air conditioner shown in FIG. 5 during cooling is as follows. The cooling / heating switching valve 56 is opened during cooling. The refrigerant vapor (HFC-134a) is cooled and condensed by the evaporator coil of the evaporator 6 to become a refrigerant liquid, flows downward through the refrigerant liquid pipe 50 by gravity, passes through expansion valves 54 and 55, and flows through the indoor units 52 and 53. Flow into heat exchanger. The refrigerant liquid that has flowed into the heat exchanger evaporates by removing the heat of the air in the air-conditioned space, becomes refrigerant vapor, rises through the refrigerant vapor pipe 51, and flows into the evaporation coil of the evaporator 6. Since the outdoor unit (absorption type cold heat generating device) is operated in the cooling mode, the evaporation coil of the evaporator 6 is cooled by the evaporation of the water refrigerant dropped on its surface, and the refrigerant vapor (flowing into the evaporation coil) ( HF
C-134a) is condensed and liquefied. Due to this condensation and liquefaction, the pressure inside the evaporating coil decreases, and the refrigerant vapor evaporated in the heat exchanger of the indoor unit is sucked into the evaporator. Since the refrigerant liquid condensed and liquefied inside the evaporation coil flows into the indoor unit by gravity, the refrigerant (HFC-134a) during cooling naturally circulates, and it is not necessary to drive the refrigerant by the pump.

When the cooling operation is started, as described above, the pressure inside the evaporation coil decreases, and the saturated refrigerant vapor in the refrigerant vapor pipe flows into the evaporation coil due to the pressure difference. The refrigerant liquid condensed and generated in the evaporation coil is the refrigerant liquid pipe 5
The head (liquid column) of the refrigerant liquid rises as it flows down in 0 by its own weight. In order for the above-mentioned natural circulation of the refrigerant to be established, it is sufficient that (refrigerant liquid head-refrigerant gas head) is not less than the total pressure loss of the refrigerant circulation path. That is, the natural circulation of the refrigerant is not started until the liquid head satisfying the following equation is formed. This means that the heat load supplied to the evaporator 6 at the start of the cooling operation is small.

[0013]

[Equation 1]

During heating, the cooling / heating switching valve 56 is closed. The refrigerant liquid (HFC-134a) is heated by the evaporator coil of the evaporator 6 to become refrigerant vapor, flows down the refrigerant vapor pipe 51, and flows into the heat exchangers of the indoor units 52 and 53. The refrigerant vapor flowing into the heat exchanger is deprived of heat by the air in the air-conditioned space to be condensed and liquefied, and becomes a refrigerant liquid that flows downward through the refrigerant liquid pipe 51 and flows into the refrigerant pump 57 inlet side.
The refrigerant liquid is pressurized by the refrigerant pump 57, flows into the evaporation coil of the evaporator 6, and repeats the above cycle. At this time,
The outdoor unit is operated in the heating mode, and the evaporator 6 has the separator 2
The high temperature solution separated by is introduced and the evaporation coil is heated by this heat.

When the control by the evaporator temperature (LT control) described with reference to FIGS. 3 and 4 is directly applied to the outdoor unit of the above-mentioned absorption type refrigerant natural circulation cooling device, the cooling operation is performed.
There are the following problems. 1) The temperature range of LT0 and LT1 is narrow, and the evaporator temperature overshoots due to a sudden drop and drops to the LT1 operating temperature (freezing prevention valve opening temperature), and the freezing prevention valve 12 is operated. The concentrated solution is mixed in the refrigerant, and the cooling capacity of the evaporator is significantly reduced. When the cooling capacity of the evaporator decreases, the pressure inside the evaporation coil rises, and the natural circulation of the refrigerant with the indoor unit is hindered. The cooling capacity of the evaporator does not recover until there is almost no concentrated solution mixed in the refrigerant distributor,
In addition, it takes time for the concentrated solution mixed in the refrigerant distributor to almost disappear. Therefore, the cooling capacity of the evaporator is restored,
It will take time for the cooling operation to start up. The evaporator temperature drops sharply because the refrigerant circuit on the indoor unit side does not have a pump that forcibly circulates the refrigerant during cooling, so the amount of refrigerant circulated at the start of cooling is small, so the amount of heat exchange with the load is small and This is because the amount of heat supplied to the evaporation coil of the evaporator 6 is also small. Therefore, the cooling capacity of the evaporator at the start of the cooling operation of the outdoor unit becomes excessive with respect to the load supplied to the evaporation coil, which causes a rapid drop in the evaporator temperature. Such a sharp drop in the evaporator temperature is more remarkable when the temperature of the cooling water for cooling the absorber 5 is low. When the cooling water temperature is low, the absorption capacity of the absorber 5 increases,
Along with this, the evaporation capacity, that is, the cooling capacity of the evaporator 6 increases.

2) Before the evaporator temperature decreases to the LT1 operating temperature, the solution bypass valve 13 is opened by LT0 control, and the concentrated solution is bypassed to the upper part of the absorber instead of being guided to the upper part of the absorber, thereby lowering the absorption capacity. To suppress the evaporation of the water refrigerant in the evaporator, but the CFC refrigerant (HFC-134a)
The temperature changes rapidly, and the LT1 operation is not stopped at the diversion ratio of the conventionally used on / off control solution bypass valve 13 (bypass amount of about 10 to 20%).

The LT1 control is effective in preventing freezing of the water refrigerant in the outdoor unit, but if the set temperature is lowered, the antifreezing effect is impaired. That is, the freezing prevention valve is opened at the evaporator temperature of 1 ° C., but when it is opened at 0 ° C., for example, the water refrigerant is substantially starting to freeze, and the evaporator temperature sensor 1
Considering the accuracy and variation of No. 7, at 0 ° C, there is a high possibility that freezing of the water refrigerant circuit will lead to crystallization operation.

As described above, when a fluid that changes in phase is used as the secondary refrigerant and is naturally circulated through the secondary refrigerant during cooling,
At the start of the cooling operation, especially when the cooling water temperature is lower than the planned temperature, the absorption capacity of the absorber becomes larger than the necessary capacity corresponding to the load, the evaporator temperature drops sharply, the LT1 control operates, and the cooling rises. There is a problem that it takes a long time.
On the other hand, the opening degree of the water-refrigerant proportional valve 11 is controlled based on the evaporator temperature in order to adjust the solution concentration inside the machine as described above. FIG. 6 shows an example of the evaporator temperature and the opening degree of the water-refrigerant proportional valve corresponding to the evaporator temperature. Since the evaporator temperature also fluctuates in accordance with the fluctuation of the cooling water temperature that normally accompanies the change of the outside air condition, the fluctuation of the evaporator temperature of 2 ° C. to 6 ° C. is caused by the cooling water inlet of the absorber 5 as shown in FIG. Almost corresponds to the cooling water temperature fluctuation of 24 ° C to 32 ° C. The opening degree of the water-refrigerant proportional valve is controlled based on the evaporator temperature, and at the start of the cooling operation, as shown in FIG. 6, the evaporator temperature decreases from the initial fully closed state to 6 ° C. Start opening for the first time. This means that the supply of the water refrigerant from the condenser 4 to the evaporator 6 is restricted and the storage amount of the water refrigerant in the condenser 4 increases from the start of the operation until that time. That is, the amount of water refrigerant that is not dissolved in the absorption solution and is excluded from the circulation cycle increases, and the concentration of the circulating absorption solution increases. Therefore, the fact that the water-refrigerant proportional valve remains closed at the start of cooling increases the absorption capacity of the absorber 5 and amplifies the imbalance between the cooling capacity of the evaporator and the load supplied to the evaporation coil described above. Acts like. That is, L
It works as a cause of T1 becoming easy to operate.

An object of the present invention is to use a fluid that changes in phase as a secondary refrigerant and smoothly start the cooling operation in accordance with the load factor even when the secondary refrigerant is naturally circulated during cooling. .

[0020]

The above-mentioned object is to achieve the absorber 5
A conduit that connects the concentrated solution pipe 8A that guides the concentrated solution to the upper part and the refrigerant distributor 6B installed in the evaporator 6 via the antifreezing valve 12, and the water refrigerant from the condenser to the refrigerant distributor 6B. A water-refrigerant pipe 11B, a pipe line 11A connected in parallel with the water-refrigerant pipe and having a water-refrigerant proportional valve 11 whose opening is controlled based on the evaporator temperature, and a cooling water coil installed in the absorber. A cooling water pipe for supplying cooling water to the cooling water; and a cooling tower 42 having a blower 42A for blowing cooling air to the cooling water to cool the cooling water, the cooling fan flowing into the cooling tower. An absorption type that is configured to stop blowing air when the temperature of water drops below a preset first temperature and uses a phase-change fluid as a secondary refrigerant that circulates between the evaporator and the load. For cold heat generator In addition, a cooling water inlet temperature sensor 25 that detects and outputs the cooling water inlet temperature is provided near the inlet of the absorber 5 of the cooling water pipe, and the water-refrigerant proportional valve 11 is cooled by the cooling water inlet temperature sensor 25. This is achieved by arranging to open fully regardless of the evaporator temperature when the water temperature is lower than the second temperature which is set lower than the first temperature. When setting the second temperature,
It is desirable to set the temperature difference from the temperature of 2 ° C to 5.5 ° C.

[0021]

When the cooling operation is started, the water-refrigerant proportional valve is closed, and the water-refrigerant in the condenser is supplied to the evaporator via the water-refrigerant pipe. The water-refrigerant proportional valve remains closed until the temperature of the evaporator drops to a preset temperature, during which part of the water-refrigerant is stored in the condenser and excluded from the circulation cycle as a working fluid. And the concentration of the absorbing solution is increased. That is, the absorption capacity of the absorber tends to increase. Also, when the cooling water temperature is lower than the planned temperature, this further enhances the absorption capacity of the absorber, amplifies the imbalance between the evaporator cooling capacity and the load supplied to the evaporator at the start of cooling, and the evaporator is cooled. It means bringing the temperature close to the operating temperature of the antifreezing valve.

However, the cooling water temperature is set to a preset second temperature and the cooling water temperature returned to the cooling tower is set to a temperature lower than the first temperature which is determined to be sufficiently low that cooling by a blower is not necessary. When the temperature is lower than 2, the water-refrigerant proportional valve is fully opened regardless of the evaporator temperature,
The water refrigerant stored in the condenser is supplied to the refrigerant distributor of the evaporator. The water refrigerant supplied to the refrigerant distributor through the water refrigerant proportional valve is excess water refrigerant, and most of it flows down to the bottom of the evaporator without being evaporated and is mixed with the absorbing solution that has absorbed the refrigerant vapor in the absorber. Becomes a dilute solution. That is, the water refrigerant that has been outside the circulation cycle is returned to the circulation cycle, so that the concentration of the absorbing solution decreases, and the absorption capacity of the absorber decreases. Since the imbalance between the cooling capacity of the evaporator and the load supplied to the evaporator is reduced due to the reduction of the absorption capacity, it is possible to prevent the temperature of the evaporator from decreasing to the operating temperature of the antifreezing valve. The LT1 operation (opening of the antifreezing valve) can be avoided.

[0023]

An embodiment of the present invention will be described below with reference to FIG. The embodiment of FIG. 1 differs from that shown in FIG. 6 in that
The cooling water inlet temperature sensor 25 for detecting and outputting the cooling water inlet temperature is provided near the connection portion of the cooling water pipe 41 with the absorber 5, and the water-refrigerant proportional valve 11 is based on the output of the evaporator temperature sensor 17. The controller 59 controls the water-refrigerant proportional valve 11 to the evaporator temperature sensor as well as the stepwise control of the opening degree as well as the control by the cooling water inlet temperature output from the cooling water inlet temperature sensor 25. A point configured to control the opening based on the output of 17 and the cooling water inlet temperature sensor 25, and the evaporation coil outlet rising part of the refrigerant vapor pipe 51 and the evaporation coil connection part of the refrigerant liquid pipe 50. Other points are the same as those in FIG. 6 in that they communicate with each other via the solenoid valve 60, and thus detailed description of the configuration will be omitted. The blower 42A of the cooling tower 42 is
When the cooling water temperature at the entrance of the cooling tower is 24 ° C or higher, the cooling tower is operated. The planned operating temperature of the evaporator in this embodiment is 5 ° C., and LT control is performed in the same manner as described with reference to FIG.

FIG. 2 shows temperature conditions for controlling the opening of the water-refrigerant proportional valve 11 in this embodiment. FIG. 2 shows the relationship between the evaporator temperature, the cooling water inlet temperature, and the water-refrigerant proportional valve opening by taking the evaporator temperature on the X-axis, the cooling water inlet temperature on the Y-axis, and the water-refrigerant proportional valve opening on the Z-axis. Therefore, the controller 59 controls the opening degree of the water-refrigerant proportional valve 11 so as to satisfy this relationship. When the cooling water inlet temperature is lower than 22 ° C, the water-refrigerant proportional valve 11 is fully opened regardless of the evaporator temperature, and the cooling water inlet temperature is 22 ° C.
In the case of ℃ or more, start to open when the evaporator temperature becomes 6 ℃ or less, and fully open at 2 ℃. When the cooling water inlet temperature is 22 ° C or higher and the evaporator temperature is between 6 ° C and 2 ° C, the opening is controlled to be (6- evaporator temperature) ÷ 4 x 100%, and 6 ° C or higher. Fully closed at 2 ° C or less.

The operation at the start of the cooling operation of the embodiment shown in FIG. 1 will be described. First, when the cooling operation is started, the evaporator temperature starts to drop. The controller 59 controls the opening degree of the water-refrigerant proportional valve 11 based on the output of the evaporator temperature sensor 17 if the input cooling water inlet temperature is 22 ° C. or higher. For example, the water-refrigerant proportional valve 11 is fully opened immediately regardless of the evaporator temperature. Water refrigerant proportional valve 1
When 1 is fully opened, the water refrigerant stored in the condenser 4 is supplied to the refrigerant distributor 6B of the evaporator 6. The water refrigerant supplied to the refrigerant distributor 6B via the water-refrigerant proportional valve 11 is an excess water refrigerant, and most of it flows down to the bottom of the evaporator 6 without being evaporated, and the absorption of the refrigerant vapor absorbed by the absorber 5 Mix with the solution to form a dilute solution. That is, the water refrigerant that has been outside the circulation cycle is returned to the circulation cycle, so that the concentration of the absorbing solution decreases, and the absorption capacity of the absorber 5 decreases. Due to the decrease in the absorption capacity, the evaporator cooling capacity is decreased, the unbalance of the load supplied to the evaporator 6 is reduced, and the rapid decrease in the evaporator temperature at the start of the cooling operation is reduced. Since it is prevented that the temperature drop of the evaporator is small and the operating temperature of the antifreezing valve is lowered, it is possible to avoid the LT1 operation (opening of the antifreezing valve) at the start of the cooling operation.

When the cooling water inlet temperature is 22 ° C. or higher, the controller 59 controls the opening of the water-refrigerant proportional valve based on the input evaporator temperature, but the cooling water inlet temperature is 22 ° C.
In the above cases, the excessive cooling capacity of the evaporator due to the cooling water temperature is not large, and the risk of LT1 operation is relatively small compared to the case where the cooling water inlet temperature is less than 22 ° C.

As described above, the cooling water inlet temperature is 22 ° C.
The increase in the absorption capacity of the absorber that occurs when the temperature is as low as less than is suppressed by opening the water-refrigerant proportional valve to reduce the concentration of the absorption solution. The LT1 operation (opening of the antifreezing valve) can be avoided, and as a result, the time required for recovering the cooling capacity of the evaporator and forming the liquid head necessary for the natural circulation of the refrigerant, that is,
It is possible to prevent the time required to start the cooling operation from increasing.

In the above embodiment, the temperature of the cooling water at which the blower 42A of the cooling tower 42 is stopped (first temperature)
The second temperature is set so that the difference between the temperature (second temperature) of the cooling water at which the water-refrigerant proportional valve 11 is fully opened is 2 ° C., and this difference is set when setting the second temperature. Is 2 ℃ ~
It is desirable to set the temperature to about 5.5 ° C. The difference is 2 ℃
When it is less than 5.5 ° C., the absorption capacity may be unnecessarily reduced and the margin of the cooling capacity may be lost, and when it is higher than 5.5 ° C., the effect of suppressing the LT1 operation becomes small.

[0029]

According to the present invention, when a phase-changing fluid is naturally circulated as a secondary side refrigerant cooled by an evaporator,
Even when the cooling water temperature is lower than the planned temperature, an excessive drop in the temperature of the evaporator is suppressed when the cooling operation is started, and it is possible to prevent the concentrated solution from mixing with the water refrigerant supplied to the evaporator.
It is possible to avoid a long time required for the cooling to rise.

[Brief description of drawings]

FIG. 1 is a system diagram showing a main configuration of an embodiment of the present invention.

2 is a graph showing an example of the relationship between the opening degree of the water-refrigerant proportional valve, the evaporator temperature, and the cooling water inlet temperature in the embodiment shown in FIG.

FIG. 3 is a conceptual diagram showing an example of protection control based on evaporator temperature.

FIG. 4 is a system diagram showing an example of a conventional technique.

FIG. 5 is a system diagram showing another example of the conventional technique.

FIG. 6 is a graph showing an example of the relationship between evaporator temperature and water-refrigerant proportional valve opening.

FIG. 7 is a graph showing an example of the correlation between the evaporator temperature and the cooling water inlet temperature.

[Explanation of symbols]

1 High Temperature Regenerator 2 Separator 3 Low Temperature Regenerator 4 Condenser 5 Absorber 6 Evaporator 6B Refrigerant Distributor 7 High Temperature Solution Heat Exchanger 8 Low Temperature Solution Heat Exchanger 8A Concentrated Solution Pipe 9 Solution Circulation Pump 10 Cooling / heating Switching Valve 10A Pipe Channel 11 Water-refrigerant proportional valve 11A Pipeline 11B Water-refrigerant pipe 12 Antifreeze valve 12A Pipeline 13 Solution bypass valve 13A Pipeline 14 Cooling water circulation pump 15 Cold / hot water circulation pump 16 Cold water outlet temperature sensor 17 Evaporator temperature sensor 21 Refrigerant liquid temperature sensor 22 Solution bypass valve 25 Cooling water inlet temperature sensor 40, 41 Cooling water pipe 42 Cooling tower 42A Blower 43, 44 Cold / hot water pipe 50 Refrigerant liquid pipe 51 Refrigerant vapor pipe 52, 53 Indoor unit 54, 55 Expansion valve 56 Cooling / heating switching valve 57 Refrigerant pump 58 Check valve 59 Controller 60 Solenoid valve

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 18, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

Claims (3)

[Claims] 1. A concentrated solution pipe 8 for guiding a concentrated solution to the upper part of the absorber 5.
A conduit 12A for communicating A and a refrigerant distributor 6B installed in the evaporator 6 via an antifreezing valve 12, a water refrigerant pipe 11B for guiding a water refrigerant from the condenser 4 to the refrigerant distributor 6B, Pipeline 11A connected in parallel to the water-refrigerant pipe 11B and having a water-refrigerant proportional valve 11 whose opening is controlled based on the evaporator temperature
And a cooling water pipe 41 for supplying cooling water to a cooling water coil installed in the absorber 5, and a cooling tower 42 having a blower 42A for blowing cooling air to the cooling water to cool the cooling water. The blower 42A is configured to stop blowing air when the temperature of the cooling water flowing into the cooling tower 42 falls below a preset first temperature, and the blower 42A is provided between the evaporator 6 and the load. In the absorption type cold heat generator in which a fluid that changes in phase is used as a secondary refrigerant that circulates in the absorber, the absorber 5 of the cooling water pipe 41 is used.
A cooling water inlet temperature sensor 25 that detects and outputs the cooling water inlet temperature is provided near the inlet, and the water-refrigerant proportional valve 1 is provided.
1 is configured to be fully opened irrespective of the evaporator temperature when the cooling water temperature output by the cooling water inlet temperature sensor 25 is lower than the second temperature set lower than the first temperature. An absorption-type cold heat generator characterized by. 2. The absorption-type cold heat generator according to claim 1, wherein a temperature difference between the second temperature and the first temperature is within a range of 2 to 5.5 ° C. 3. The absorption type cold heat generating device according to claim 1, wherein the second temperature is 22 ° C.