JPS602540Y2 - absorption cold water machine - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of a heat exchanger used in an absorption chiller/heater. Alternatively, the cross-sectional area of the flow in the heat exchanger is changed so that the change in the flow velocity of the absorption liquid is slight, and the heat transfer coefficient of the heat exchanger is kept almost constant, allowing stable operation of the absorption chiller/heater. This is what I did.

Referring to the drawings, 1 is a high-temperature generator that heats and separates the refrigerant from the dilute absorption liquid, and 2 is a low-temperature generator that uses the refrigerant vapor from the high-temperature generator 1 as a reheating heat source to reheat and separate the refrigerant from the intermediate liquid. , 3 is a condenser that cools and condenses the refrigerant from the high-temperature generator 1 and the low-temperature generator 2 in a heat exchanger 4 using cooling water, and 5 is a condenser that obtains latent heat of vaporization from a built-in water heat exchanger 7 to produce cold water for cooling. 6 is an absorber that absorbs the refrigerant vaporized in the evaporator 5 with an absorption liquid, and the absorbed heat is cooled in a heat exchanger 8 using cooling water; 9 is an absorber that supplies high-temperature refrigerant; The used water heater, 10 is a refrigerant pump, 11 is an absorption liquid pump, 12.13 is an absorption liquid heat exchanger, and these are connected by a refrigerant pipe 14 and an absorption liquid pipe 15 to perform a circulation cycle of the refrigerant and absorption liquid. is formed.

Further, 16 is a cold water circulation pump for air conditioning, 17 is a hot water pump for hot water circulation, and 18 is a cooling water supply pump, and these pumps 10, 11, 16, 17. It has a mechanism that allows the amount of circulating fluid to be changed by controlling it.

FIG. 2 shows the heat used in the condenser 3, the heat exchangers 4 and 8 for cooling the absorber 6, the solution heat exchanger 12, the evaporator cold water heat exchanger 7, and the water heater 9. It is a diagram showing an example of the structure of the exchanger 19, in which the liquid flow path extends from a plurality of pipe groups 20 and 21, and a switching valve 24 is provided on the water inlet side 22 and outlet side 23.
．． 25. 26 is arranged, and the inlet side 22 and the outlet side 23 are connected by a side pipe 27.

In the proposed absorption chiller/heater having such a configuration, under normal operating conditions, the switching valve of the water heat exchanger is in the state shown in Figure 2, and heat exchange is performed according to the rated flow rate (100%). .

As a result, the cooling (or heating) load is reduced, and the rotational speed and number of operating units of the cold water (or hot water) pumps 16, 17 or accompanying cooling water pumps 18 and absorption liquid pumps 11 are controlled, and heat exchange is performed. If the flow rate of the water heat exchangers 4, 7, 8, 12, 19 is reduced by half, the water flow cross-sectional area of the water heat exchanger is halved by opening and closing the switching valves 24 to 26 in the opposite direction to that shown in the diagram. This prevents the reduction in water flow rate caused by the control from reducing the water flow rate and heat transfer within the heat exchanger.

That is, when the switching valves 24 and 25 in FIG. As a result, the number of tube groups in the water flow path that can flow simultaneously is halved, and the cross-sectional area of water flow in the water heat exchanger is halved. This does not appear as a decrease in the flow rate of water flowing through the heat exchanger, thereby preventing a decrease in the heat transfer coefficient of the heat exchanger.

Therefore, even if, for example, when the cooling load is halved, the discharge amount of the pump 16 is halved and the amount of cold water circulated is halved.
The amount of heat exchanged between the refrigerant and cold water in the heat exchanger 17 is also reduced by almost half, and the load side is supplied with cold water corresponding to the load, and the heat exchanger 1
The temperature at the inlet and outlet of the cold water at 7 and the temperature inside the evaporator 5,
The pressure is also maintained at approximately the same level as before the load change.

That is, when the circulating amount of cold water is changed, the temperature inside the evaporator 5 changes, which affects the absorber 6 and other equipment, causing damage such as unstable operation of the absorption chiller/heater. do not have.

As described above, according to the present invention, it is possible to eliminate imbalanced temperature changes in the various parts of the absorption chiller that may occur when the cooling/heating load is reduced, and to enable stable operation of the absorption chiller/heater even under low load.

It should be noted that it is not necessary to control all of these heat exchangers 4, 7, 8, 12, and 19 at the same time, and the present proposal is limited to those parts where a decrease in heat transfer coefficient becomes a problem in the operation of such an absorption chiller/heater. In this case, it is preferable that the opening/closing signals for the valves of the cold water, hot water, and cooling water systems are activated by the control start/stop of each pump, and the opening/closing signals of the valves of the solution heat exchanger are activated by the cooling load. .

[Brief explanation of drawings]

FIG. 1 is a cycle configuration diagram showing an example of an absorption chiller/heater, and FIG. 2 is a diagram showing an example of the structure of a heat exchanger used in the present invention. 1.2... Generator, 3... Condenser, 5
...Evaporator, 6...Absorber, 4.7.
8. 12. 13. 19...Heat exchanger, 1
0,11,16.17.18...Liquid pump,
24, 25, 26...Switching valve.

Claims (1)

[Scope of utility model registration request] generator, condenser, evaporator, absorber, water heater, heat exchanger,
A liquid pump that can change the amount of liquid circulation is connected with a refrigerant pipe and an absorption liquid pipe to form a circulation cycle for the refrigerant and absorption liquid, and a heat exchanger for the condenser, a heat exchanger for the evaporator, and a heat exchanger for the absorber are connected. A liquid pump that can change the flow rate of water is connected to each of the heat exchanger and the water heater heat exchanger with a pipe to form a water flow path, and one or more of the above heat exchangers By using a heat exchanger equipped with a switching valve that can change the cross-sectional area of the flow, the cross-sectional area of the flow in the heat exchanger can be increased or decreased in accordance with the increase or decrease in the flow rate caused by the liquid pump. An absorption chiller/heater featuring: