JP3111205B2 - Exhaust heat recovery type absorption chiller / heater and its control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an exhaust heat recovery type absorption chiller / heater operating by recovering exhaust heat of a gas engine or the like, and more particularly to a gas engine used in a cogeneration system and other exhaust systems. The present invention relates to an exhaust heat recovery type absorption chiller / heater for recovering heat and a control method thereof.

[0002]

2. Description of the Related Art In a cogeneration system in which exhaust heat of a gas engine or the like is effectively used for cooling and power generation and heat recovery are efficiently performed, the exhaust heat is recovered with an absorbing solution, thereby reducing gas input and cooling efficiency. An exhaust heat recovery type absorption chiller / heater has been devised to improve the efficiency. In such a chiller / heater system, when the cooling load is reduced and the output needs to be reduced, the gas input is stopped, the operation of the absorption chiller / heater is stopped, and the absorption solution is discharged by the exhaust heat. In order to prevent crystallization in the waste heat exchanger due to concentration of the waste heat, the waste heat is bypassed by a three-way valve or the like to prevent heat input to the absorption chiller / heater.

[0003]

However, the power load and the air-conditioning load do not necessarily increase or decrease in the same manner.
As shown in (1), the exhaust heat of the cooling water was radiated to the atmosphere by a separately mounted radiator for radiation, and the temperature was lowered before use as cooling water for the engine. In this case, a radiator for heat dissipation, a three-way valve and control means for them are required, and the system becomes complicated, and at the same time, the initial cost increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide an exhaust heat recovery type absorption chiller / heater to which an exhaust heat exchanger for effectively using exhaust heat of a gas engine or the like as a heat source for cooling is provided. The purpose is to discharge exhaust heat without providing any heat radiation means and to simplify the system.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cooling water flow path provided with a heat transfer surface, wherein a concentrated solution sprayed on the heat transfer surface absorbs refrigerant vapor to produce a dilute solution. A cooling tower provided to be connected to the cooling water flow passage to cool the cooling water circulating in the cooling water flow passage; and a waste heat heat for heating the diluted solution generated and circulated in the absorber by using the waste heat as a heat source. Exchanger, and a high-temperature regenerator to which the diluted solution heated by the waste heat heat exchanger is introduced and further heated, wherein the waste heat recovery type absorption chiller / heater comprises: This is achieved by providing exhaust heat discharging means for guiding the dilute solution that has passed through to the absorber and dispersing it on the heat transfer surface.

Further, the exhaust heat releasing means includes a solution stop valve A interposed in a pipe for guiding the dilute solution heated by the exhaust heat exchanger to the high temperature regenerator, and an upstream and downstream of the solution stop valve A. It may be configured to include a solution bypass pipe that communicates with a pipe for guiding the solution to the absorber via a solution stop valve B. Further, it is preferable to provide control means for opening the solution stop valve A and closing the solution stop valve B during the cooling operation, and for closing the solution stop valve A and opening the solution stop valve B when the cooling operation is stopped.

The above object is further achieved by providing a cooling water flow path provided with a heat transfer surface and absorbing the refrigerant vapor into a concentrated solution sprayed on the heat transfer surface to generate a dilute solution; A cooling tower that is provided connected to the water flow path and cools the cooling water circulating in the cooling water flow path, and a waste heat heat exchanger that heats the dilute solution generated and circulated in the absorber using waste heat as a heat source, A high-temperature regenerator to which the diluted solution heated by the exhaust heat exchanger is introduced and further heated, wherein the exhaust heat recovery type absorption chiller / heater comprises: This is also achieved by continuing to supply the exhaust heat to the exchanger, guiding the dilute solution passing through the exhaust heat exchanger to the absorber, and spraying the diluted solution on the heat transfer surface.

[0008]

The case where the cooling load is reduced and the operation of the water heater / heater is stopped will be described. In order to stop the operation of the chiller / heater, the heating in the high-temperature regenerator 1 is stopped. The dilute solution in the absorber is sent to the waste heat exchanger, and passes while being heated using the waste heat as a heat source. The dilute solution that has been heated by the exhaust heat exchanger and has recovered the exhaust heat is guided to the absorber by the exhaust heat releasing means and is spread on the heat transfer surface. Since the operation of the cooling water pump is continued, the cooling water is also circulating, and the heat collected by the waste heat exchanger from the dilute solution sprayed on the heat transfer surface is transferred to the cooling water via the heat transfer surface. Is done. The heat transferred to the cooling water is transferred to the cooling tower, where it is released to the atmosphere. On the other hand, the dilute solution that has given heat to the cooling water via the heat transfer surface is again sucked into the solution circulation pump from the absorber, pressurized and sent to the waste heat exchanger, and repeats the above-described circulation. Due to such circulation of the dilute solution and the cooling water, even when the cooling operation is stopped, the exhaust heat is sent to the exhaust heat exchanger, the dilute solution, the heat transfer surface, the cooling water, and the cooling tower in this order, and continues from the cooling tower. Is released to the atmosphere.

As a waste heat releasing means, a pipe (23) for leading the dilute solution heated in the waste heat exchanger (12) to the high temperature regenerator (1).
A solution stop valve A (11) interposed in B), and a pipe (20) for introducing the concentrated solution to the absorber on the upstream side of the solution stop valve A (11).
And a solution bypass pipe (21) communicating through a solution stop valve B (10) to open and close the solution stop valve A (11) and the solution stop valve B (10). By simply performing the operation, the dilute solution heated in the exhaust heat exchanger (12) can be sprayed on the heat transfer surface of the absorber.

Also, by providing a control means for opening and closing the solution stop valve A (11) and the solution stop valve B (10) in conjunction with the presence or absence of the cooling operation, the control of the controller provided conventionally Signals can be used as they are, and control can be simplified.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An exhaust heat recovery type absorption chiller / heater according to an embodiment of the present invention will be described with reference to FIG. This absorption chiller / heater uses lithium bromide (Li) as an operating fluid.
An absorption solution in which water as a refrigerant is absorbed in Br) is used. The LiBr concentration of the absorbing solution fluctuates as the working fluid circulates through the apparatus, and this fluctuation can be roughly divided into three stages. From the lower concentration level, the dilute solution, the intermediate concentrated solution, and the concentrated solution are called. .

The illustrated exhaust heat recovery type absorption chiller / heater has a high temperature regenerator 1 provided with means for heating an absorbing solution (dilute solution) contained therein, and a high temperature regenerator 1 disposed above the high temperature regenerator 1.
, A low-temperature regenerator 3 equipped with a refrigerant vapor coil 24 having one end connected to a gas phase portion of the separator 2, and a secondary refrigerant vapor connected to the low-temperature regenerator 3. A condenser 4 having the other end of the refrigerant vapor coil 24 connected thereto in a passage and having a cooling water coil 4A therein, and an evaporator 5 having a refrigerant pipe 17 connected to the condenser 4 and having an evaporation coil 5A therein. An absorber 6 which communicates with the evaporator 5 through an evaporating refrigerant vapor passage and has a cooling water coil 6A therein; a solution circulation pump 9 having a suction side connected to a bottom of the absorber 6 by a dilute solution suction pipe 22; A low-temperature solution heat exchanger 7 having a heated fluid inlet side connected to the discharge side of the circulation pump 9; and a heated fluid inlet side via a dilute solution discharge pipe 23A on the heated fluid outlet side of the low-temperature solution heat exchanger 7 Exhaust heat exchanger 12 connected to
A high-temperature solution heat exchanger 8 having a heated fluid inlet side connected to a heated fluid outlet side of the exhaust heat exchanger 12 via a dilute solution discharge pipe 23B, and a heated fluid of the high-temperature solution heat exchanger 8 A dilute solution discharge pipe 23C connecting the outlet side to the dilute solution inlet of the high temperature regenerator 1 and an intermediate concentrated solution pipe 15A connecting the liquid phase part of the separator 2 and the heating fluid inlet of the high temperature solution heat exchanger 8
And the heating fluid outlet side of the high-temperature solution heat exchanger 8 and the low-temperature regenerator 3
Concentrated solution tube 15B connecting the upper part of the low temperature regenerator 3
A concentrated solution tube 19 connecting the bottom of the low temperature solution heat exchanger 7 with the heated fluid inlet side, a concentrated solution tube 20 connecting the low temperature solution heat exchanger 7 with the heated fluid outlet side and the top of the absorber 6, A solution stop valve 11 interposed in the solution discharge pipe 23B; a dilute solution discharge pipe 23B and a concentrated solution pipe 2 upstream of the solution stop valve 11;
0, via a solution stop valve 10, a solution bypass pipe 21, a cooling water pipe 18C connecting the outlet side of the cooling water coil 4A and the cooling water inlet side of the cooling tower 14, and a suction side to the cooling water outlet side of the cooling tower 14. , A cooling water pipe 18A connecting the discharge side of the cooling water pump 13 and the inlet side of the cooling water coil 6A, and the outlet side of the cooling water coil 6A and the side entering the cooling water coil 4A. And a cooling water pipe 18B to be connected.

The cooling water coil 6A has an outer peripheral surface serving as a heat transfer surface, and an internal portion serving as a cooling water flow path through which cooling water flows. The heating fluid inlet side of the exhaust heat exchanger 12 is connected to the cooling water outlet side of the gas engine, and the heating fluid outlet side is connected to the cooling water inlet side of the gas engine. Solution stop valve 1
Reference numerals 0 and 11 denote solenoid valves whose opening and closing are controlled by a controller (not shown) of the water heater / heater. The controller closes the solution stop valve 10 during the cooling operation, opens the solution stop valve 11, operates the cooling water pump 13 and the solution circulation pump 9, operates the high temperature regenerator 1, and stops the cooling operation when the cooling operation is stopped. Control means for opening the valve 10, closing the solution stop valve 11, operating the cooling water pump 13 and the solution circulation pump 9, and stopping the high-temperature regenerator 1 (the other control of the controller is omitted). I have.

In the above configuration, the solution stop valve 1
It is different from the prior art shown in FIG. 2 in that the exhaust heat discharging means including 0, 11 and the solution bypass pipe 21 is provided, and the radiator for radiation and the three-way valve are not provided. In this embodiment, the gas engine is used as the heat source of the exhaust heat. However, it is naturally possible to use a heat source other than the gas engine.

The operation of the absorption chiller / heater of the above configuration during normal operation will be described below. The diluted solution in the high-temperature regenerator 1 is heated, rises in the riser 25 in a gas-liquid two-phase state, and flows into the separator 2. The dilute solution in a gas-liquid two-phase state that has flowed into the separator 2 is separated into a refrigerant vapor and an intermediate concentrated solution, and the refrigerant vapor flows into the condenser 4 via a refrigerant vapor coil 24 provided in the low-temperature regenerator 3. The concentrated solution flows into the heated fluid side of the high-temperature solution heat exchanger 8 via the intermediate concentrated solution pipe 15A. The intermediate concentrated solution that has flowed into the high-temperature solution heat exchanger 8 passes through the heat exchanger 8 while heating the dilute solution flowing on the side of the fluid to be heated.
5B, flows into the low-temperature regenerator 3 and passes through the refrigerant vapor coil 24.
Sprinkled on top. The refrigerant vapor flowing in the refrigerant vapor coil 24 heats the surrounding intermediate concentrated solution to evaporate the refrigerant to produce a secondary refrigerant vapor, which is cooled and condensed to form a gas-liquid two-phase condenser 4. Flows into. The secondary refrigerant vapor generated by the low-temperature regenerator 3 also flows into the condenser 4 through the secondary refrigerant vapor passage, and is cooled together with the refrigerant flowing through the refrigerant vapor coil 24 to the cooling water flowing in the cooling water coil 4A. Is condensed and becomes a liquid refrigerant.

The liquid refrigerant generated in the condenser 4 is supplied to the refrigerant pipe 1
7, flows into the evaporator 5, is spread on the evaporator coil 5 </ b> A provided in the evaporator, evaporates by removing the heat of the heat medium flowing in the evaporator coil 5 </ b> A, and turns into refrigerant vapor again. After that, it flows into the absorber 6. The heat medium that has been deprived of heat and cooled is guided to a cooling load, performs cooling, and returns to the evaporating coil 5 again. The intermediate concentrated solution obtained by evaporating the refrigerant as the secondary refrigerant vapor in the low-temperature regenerator 4 becomes a concentrated solution and flows into the low-temperature solution heat exchanger 7 through the concentrated solution pipe 19 into the heating fluid inlet side. The concentrated solution that has flowed into the low-temperature solution heat exchanger 7 passes through the low-temperature solution heat exchanger 7 while heating the dilute solution flowing on the heated fluid side, and flows into the absorber 6 via the concentrated solution pipe 20. In a normal operation state, the solution stop valve 10 is closed. The concentrated solution that has flowed into the absorber 6 is sprayed on the cooling water coil 6A, absorbs the refrigerant vapor flowing from the evaporator, and becomes a dilute solution. The heat of absorption generated when the concentrated solution absorbs the refrigerant vapor is transferred to the cooling water flowing in the cooling water coil 6A, and is carried to the cooling tower 14.

The dilute solution generated by the absorber 6 is sucked into the solution circulation pump 9 through the dilute solution suction pipe 22, is pressurized, and flows into the low temperature solution heat exchanger 7 on the side of the fluid to be heated. The dilute solution flowing into the low-temperature solution heat exchanger 7 passes through the low-temperature solution heat exchanger 7 while being heated by the concentrated solution flowing on the heating fluid side, passes through the dilute solution discharge pipe 23A, and is heated by the waste heat heat exchanger 12. Flows into the side. The dilute solution flowing into the exhaust heat exchanger 12 is
While being heated by the gas engine cooling water flowing on the heating fluid side, it passes through the exhaust heat exchanger 12 and passes through the dilute solution discharge pipe 23B (the solution stop valve 11 is open in the normal operation state).
It flows into the heated fluid side of the high-temperature solution heat exchanger 8. The dilute solution flowing into the high-temperature solution heat exchanger 8 passes through the high-temperature solution heat exchanger 8 while being heated by the intermediate concentrated solution flowing on the heating fluid side, and flows into the high-temperature regenerator 1 via the dilute solution discharge pipe 23C. The dilute solution flowing into the high-temperature regenerator 1 repeats the above cycle again.

The cooling water taken out by the cooling water coil 6A and the condensing heat taken out by the cooling water coil 4A flows into the cooling tower 14 through the cooling water pipe 18C, and transfers the absorbed heat and the condensed heat to the atmosphere. discharge. Further, the gas engine cooling water which has transferred the exhaust heat to the dilute solution while flowing on the heating fluid side of the exhaust heat exchanger 12 returns to the gas engine after exiting the exhaust heat exchanger 12 and cools the gas engine. The cycle described above is repeated for the operation during normal operation.

Next, the case where the cooling load is reduced and the operation of the chiller / heater is stopped will be described. In order to stop the operation of the chiller / heater, the heating in the high temperature regenerator 1 is stopped, but the operation of the solution circulation pump 9 and the cooling water pump 13 is continued. Next, the solution stop valve 10 is opened, the solution stop valve 11 is closed, and the dilute solution that has passed through the exhaust heat exchanger 12 flows into the absorber 6 via the solution bypass pipe 21 and the solution stop valve 10. That is, the dilute solution sent from the solution circulation pump is heated while passing through the exhaust heat exchanger 12 using exhaust heat of a gas engine or the like as a heat source, and is passed through the solution bypass pipe (solution bypass circuit) 21 to the absorber 6. And the heat is taken away by the cooling water circulating in the cooling water coil 6A in the absorber and cooled. The cooled diluted solution is sucked into the solution circulation pump 9 through the diluted solution suction pipe 22 from the bottom of the absorber, pressurized and returned to the exhaust heat exchanger 12 through the low-temperature solution heat exchanger 7, and the cycle described above is repeated. continue.

The cooling water flowing through the cooling water coil 6A in the absorber is cooled in the order of the cooling water coil 4A of the condenser 4, the cooling tower 14 for the chiller / heater, the cooling water pump 13, and the cooling water coil 6A in the absorber. The water is circulated by being driven by the water pump 13, and the heat taken from the dilute solution by the cooling water coil 6 </ b> A is carried to the cooling tower 14 for the chiller / heater, and is released to the atmosphere.

By forming and maintaining such a cycle of the dilute solution when the cooling operation is stopped, the absorption solution (dilute solution) is used as a heat transfer medium even when the absorption chiller / heater is in the cooling operation. Since the heat of the engine cooling water can be dissipated by the cooling tower, there is no need to provide a separate radiator for heat dissipation. When the absorption chiller / heater performs the cooling operation, the solution bypass valve 11 is opened and the solution bypass valve 10 is closed, so that the absorption solution is discharged to the exhaust heat exchanger 1.
In step 2, the exhaust heat of the engine is recovered, and at the same time, the heat is circulated through the normal cooling cycle route, so that the heat input to the high-temperature regenerator 1 can be reduced.

[0022]

According to the first aspect of the present invention, the exhaust heat during the cooling operation stop can be released to the atmosphere without providing a special radiator or a three-way valve.

According to the invention described in claim 2, according to claim 1
In addition to the effects of the invention described in (1), the exhaust heat release means can be realized with a simple configuration.

According to the invention of claim 3, according to claim 2,
In addition to the effects of the invention described in the above, the opening and closing operation of the valve when the cooling operation is stopped or when the cooling operation is switched from the stopped state to the cooling operation is automated, and the risk of erroneous operation is eliminated.

According to the invention of claim 4, according to claim 1,
Has the same effects as the effects of the invention described in (1).

[Brief description of the drawings]

FIG. 1 is a system diagram showing an exhaust heat absorption chiller / heater according to an embodiment of the present invention.

FIG. 2 is a system diagram showing an example of the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 High temperature regenerator 2 Separator 3 Low temperature regenerator 4 Condenser 4A Cooling water coil 5 Evaporator 5A Evaporation coil 6 Absorber 6A Cooling water coil 7 Low temperature solution heat exchanger 8 High temperature solution heat exchanger 9 Solution circulation pump 10 Solution stop Valve 11 Solution stop valve 12 Waste heat exchanger 13 Cooling water pump 14 Cooling tower 15A, 15B
Intermediate concentrated solution pipe 17 Refrigerant pipe 18A, 18
B, 18C Cooling water pipe 19 Concentrated solution pipe 20 Concentrated solution pipe 21 Solution bypass pipe 22 Dilute solution suction pipe 23A-23C Dilute solution discharge pipe 24 Refrigerant vapor coil 25 Rise pipe

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masahiro Oka 7-14-7 Minamikoiwa, Edogawa-ku, Tokyo (56) References JP-A-7-218018 (JP, A) JP-A 8-152222 (JP, A) ) Actually open sho 55-28870 (JP, U)

Claims (4)

(57) [Claims] 1. An absorber for providing a cooling water flow path provided with a heat transfer surface, absorbing a refrigerant vapor into a concentrated solution sprayed on the heat transfer surface to generate a dilute solution, and connected to the cooling water flow path. A cooling tower for cooling the cooling water circulating in the cooling water flow path, a waste heat exchanger for heating the dilute solution generated by the absorber and circulating using the waste heat as a heat source, A high-temperature regenerator to which the diluted solution heated by the exchanger is introduced and further heated, wherein the diluted solution that has passed through the waste heat exchanger is absorbed by the absorber. An exhaust heat recovery type absorption chiller / heater comprising: an exhaust heat release means for guiding the heat to the heat transfer surface and dispersing the heat on the heat transfer surface. 2. A waste heat discharging means comprising: a solution stop valve A interposed in a pipe for guiding a dilute solution heated by a waste heat heat exchanger to a high-temperature regenerator; The exhaust heat recovery type absorption chiller / heater according to claim 1, further comprising: a solution bypass pipe for connecting a pipe for guiding the solution to the absorber via a solution stop valve B. 3. 3. A control means for opening the solution stop valve A and closing the solution stop valve B during the cooling operation, and providing control means for closing the solution stop valve A and opening the solution stop valve B when the cooling operation is stopped. Item 3. An exhaust heat recovery type absorption chiller / heater according to Item 2. 4. An absorber for providing a cooling water flow path having a heat transfer surface therein and absorbing a refrigerant vapor to a concentrated solution sprayed on the heat transfer surface to generate a dilute solution, and connected to the cooling water flow path. A cooling tower for cooling the cooling water circulating in the cooling water flow path, a waste heat exchanger for heating the dilute solution generated by the absorber and circulating using the waste heat as a heat source, A high-temperature regenerator to which a dilute solution heated by an exchanger is introduced and further heated, and a method of controlling an exhaust heat recovery type absorption chiller / heater comprising: A method for controlling an exhaust heat recovery type absorption chiller / heater, wherein the supply of exhaust heat is continued, and the dilute solution passing through the exhaust heat exchanger is guided to the absorber and dispersed on the heat transfer surface. .