JPH11108495A - Heat utilizing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an entire thermal efficiency in a configuration for supplying concurrently both cold water and hot water by a method wherein residual hot water returned from a hot water utilization device is mixed with hot water heated by an absorbing type freezer, thereafter supplied to the hot water utilization device. SOLUTION: Steam generated by a discharged gas boiler 18 and steam generated by an auxiliary boiler 19 are mixed to each other, supplied to an absorbing type freezer 24 to become water and then it is recovered in a water circulating tank at 22. A first system for hot water HW (R) returned from the hot water utilization device supplied through a piping 31 is heat exchanged with refrigerant steam of high temperature and high pressure flowing in a condenser 14 so as to increase its temperature. Further, jacket water is circulated through a heat exchanger 17A and a heat exchanger 17B so as to increase its temperature. In addition, the second system for the returned hot water HW (R) receives heat through an absorbing device 28 of the absorbing type freezer 24 and a condenser 26 to increase its temperature. The hot water in the first system and the hot water in the second system are mixed to each other and supplied from the piping 32 to the hot water utilization device as the feeding hot water HW (S).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat utilization system for supplying cold and hot water to a utilization side using an engine such as an engine or a gas engine, and more particularly to a system utilizing the driving force and exhaust gas of the engine effectively. The present invention relates to a heat utilization system with improved thermal efficiency.

[0002]

2. Description of the Related Art Conventionally, various types of refrigerators such as a centrifugal refrigerator and an absorption refrigerator and a device utilizing high-temperature exhaust gas have been known as devices for obtaining cold or hot water.

For example, Japanese Patent Application Laid-Open No. Hei 5-187206 discloses a method of utilizing high-temperature exhaust gas, in which high-temperature exhaust gas is guided to an exhaust gas boiler to generate steam, and the steam is used as a heat source of an absorption refrigerator to generate cold water. An obtained exhaust heat recovery system is shown, and JP-A-8-232681 discloses a system in which exhaust gas of a gas turbine is passed through a water heater to heat water and supply hot water.

[0004]

However, in the above-mentioned conventional apparatus for obtaining cold or hot water, only the structure for obtaining either cold or hot water is used, so that its energy efficiency is sufficiently high. A high one could not be obtained. Further, it has been difficult to increase the overall energy efficiency only by combining cold water and hot water so that they can be simultaneously supplied.

In view of such circumstances, the present invention combines two types of different refrigerators to effectively use the driving force of an engine and exhaust gas, and also recovers waste heat radiated from cold water to generate hot water. It is an object of the present invention to provide a heat utilization system in which cold water and hot water are simultaneously supplied by effectively utilizing the heat utilization system with improved thermal efficiency as a whole.

[0006]

SUMMARY OF THE INVENTION A heat utilization system according to the present invention comprises an exhaust gas boiler that generates steam using an exhaust gas of an engine as a heat source, a boiler for generating steam, a refrigerant compressor driven by the engine, and a condenser. Compression refrigerator including a steam generator, a decompression device, and an evaporator, and an absorption refrigerator including a regenerator, a condenser, an evaporator, and an absorber using steam generated by the exhaust gas boiler and steam generated by the boiler as a heat source. Cooling the return cold water from the cold water utilization device with the evaporator of the compression refrigerator, and then supplying a cold water pipe to the cold water utilization device; and returning part of the hot water from the hot water utilization device to the compression refrigerator. The hot water supplied to the hot water utilization device after mixing the hot water heated by the condenser and the hot water heated in order by the rest of the return hot water from the hot water utilization device in the absorber and the condenser of the absorption refrigerator, Plumbing, Cooler for serial engine is characterized in that comprising a pipe cooling water circulation pipe to cool with evaporator of the absorption refrigerator.

Further, a configuration may be adopted in which a part of the return hot water from the hot water utilization device is heated by a condenser of the compression refrigerator and then reheated by heat exchange with jacket cooling water of the engine. .

Further, an air cooler for cooling air from a supercharger and an oil cooler for cooling oil of the engine may be configured to be cooled by using an evaporator of the absorption refrigerator.

Then, it is preferable to detect the temperature of the cold water supplied to the cold water utilization device and control the amount of fuel supplied to the engine so that the temperature of the cold water becomes a predetermined temperature.

Preferably, the temperature of the chilled water supplied to the chilled water utilization device is detected, and the amount of fuel supplied to the engine is controlled so that the temperature of the chilled water becomes a predetermined temperature.

Alternatively, the temperature of the chilled water supplied to the chilled water utilization device is detected so that the temperature becomes a predetermined temperature.
Controlling the amount of fuel supplied to the engine, detecting the temperature of the brine coming out of the evaporator of the absorption refrigerator used for cooling the cooler for the engine, and determining the temperature of the brine in advance. Temperature
Preferably, the amount of fuel supplied to the boiler is controlled.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a heat utilization system of the present invention. The heat utilization system of the present invention mainly includes an engine facility, a boiler facility, a compression refrigerator, and an absorption refrigerator. Cold water and hot water are circulated and supplied to a heat (cold water, hot water) utilization device (not shown).

The engine equipment includes an engine 1, a flow control valve 2 for controlling the supply of city gas as fuel, a supercharger 3 for supplying air to the engine 1, and cooling of air from the supercharger 3. Air cooler 4 to supply to engine 1
And an oil cooler 5 for cooling the engine oil of the engine 1, a jacket 6 through which a jacket water for cooling the engine 1 flows, and a heat exchanger 17 for cooling the jacket water.

The fuel via the flow control valve 2, the city gas as the fuel, and the air obtained from the supercharger 3 via the air cooler 4 are supplied to drive the engine 1. The driving force generated by the engine 1 is transmitted to the compression refrigerator.
The exhaust gas is supplied to the absorption refrigerator through the exhaust gas boiler as an energy source from the engine equipment.
Further, engine oil whose temperature has been increased by driving the engine 1 is sent to the oil cooler 5. Cooling water is externally supplied to the air cooler 4 and the oil cooler 5 to cool the air and oil compressed by the supercharger 3, while the cooling water is cooled by the air compressed by the air cooler 4 and the oil cooler 5. The temperature rises due to oil radiation. Further, by driving the engine 1, the temperature of the jacket water circulating between the jacket 6 and the heat exchanger 17A also increases, but is cooled by the cooling water supplied to the heat exchanger 17A.

The jacket water of the engine 1 circulates between the jacket 6 and the heat exchanger 17A.
If the temperature of the jacket water returning to the jacket 6 deviates from a predetermined temperature, for example, 80 ° C., the operation of the engine 1 may be hindered. Therefore, the bypass amount of the heat exchanger 17A is changed by the flow control valve 7. By changing the cooling water flowing from the heat exchanger 17B to the heat exchanger 17A, the temperature of the jacket water returning to the jacket 6 is controlled to a predetermined temperature.

Similarly, if the temperature of the engine oil circulating in the engine 1 and the oil cooler 5 returning to the engine 1 side deviates from a predetermined temperature, the operation of the engine 1 may be hindered. The temperature at which the engine oil returns to the engine 1 is controlled to a predetermined temperature by changing the amount of cooling water to be passed.

The boiler equipment includes an exhaust gas boiler 18 to which exhaust gas from the engine 1 is supplied, an auxiliary boiler 19,
The auxiliary boiler 19 includes a flow control valve 20 for controlling the supply amount of fuel, a return water tank (hot well tank) 22 for supplying water to the exhaust gas boiler 18 and the auxiliary boiler 19, and a pump 23.

With this configuration, the water supplied from the return water tank (hot well tank) 22 to the exhaust gas boiler 18 and the auxiliary boiler 19 by the pump 23 depends on the calorific value of the exhaust gas supplied from the engine 1 by the exhaust gas boiler 18 and ,
The combustion of the fuel supplied through the flow control valve 20 in the auxiliary boiler 19 converts the fuel into high-temperature and high-pressure steam. The high-temperature and high-pressure steam generated in the exhaust gas boiler 18 and the auxiliary boiler 19 are mixed and supplied to the absorption refrigerator 24.

The compression refrigerator has a configuration in which a condenser 14, a pressure reducing valve 15, an evaporator 16 and the like are circulated and connected by a refrigerant pipe to a turbo compressor 13 coupled to the engine 1 via gears and the like.

With this configuration, the low-temperature and low-pressure refrigerant gas from the evaporator 16 is compressed by the compressor 13 to become a high-temperature and high-pressure refrigerant gas. The high-temperature and high-pressure refrigerant gas enters the condenser 14 and is cooled and liquefied by the return hot water from the hot water utilization device described later, while the return hot water as the cooling water is heated to increase its temperature. The refrigerant cooled and liquefied by the condenser 14 is reduced in pressure by the pressure reducing valve 15 and flows into the evaporator 16. The refrigerant liquid that has flowed into the evaporator 16 due to the decrease in pressure deprives the return chilled water from the chilled water utilization device described later and evaporates at a low pressure and a low temperature, while cooling the return chilled water to lower its temperature. On the other hand, the evaporated low-temperature and low-pressure refrigerant gas is again sucked into the compressor 13 and compressed into a high-temperature and high-pressure refrigerant gas. The refrigerant repeats this refrigeration cycle.

The absorption refrigerator 24 uses water as a refrigerant, and uses lithium bromide, which absorbs water very easily, as an absorption solution. The configuration is such that a high-temperature and high-pressure steam generated and mixed in the exhaust gas boiler 18 and the auxiliary boiler 19 is supplied as a heat source, and a regenerator 25 for generating a refrigerant vapor from an absorbing solution absorbing the refrigerant by the high-temperature and high-pressure vapor.
A condenser 26 for heating the returned hot water to be passed to raise the temperature, an evaporator 27 for recovering heat from the returned cold water and lowering the temperature, and heating the returned hot water to be passed. And an absorber 28 for raising the temperature.

Although not shown, refrigerant vapor generated in the regenerator 25 is supplied to the condenser 26 and the refrigerant liquid condensed in the condenser 26 is supplied to the evaporator 2.
7 is connected to a refrigerant pipe through which the refrigerant vapor supplied to the evaporator 7 and evaporated by the evaporator 27 is supplied to the absorber 28. In the absorber 28, the supplied refrigerant vapor is absorbed by the absorbing solution. In addition, the absorbing solution having absorbed the refrigerant is supplied to the regenerator 25 to evaporate the refrigerant, and the piping is connected so that the absorbing solution in which the refrigerant has evaporated to a concentrated solution is returned to the absorber 28 again. . In this way, the absorption refrigerator 24 has a circulation path for the refrigerant and the absorption solution (not shown) that connects the respective containers to the pipes.

When steam is supplied as an external heating source to the regenerator 25 of the absorption refrigerator 24, refrigerant vapor is generated from the absorbing solution absorbing the refrigerant. The refrigerant vapor enters the condenser 26 and heats and condenses the hot water that has been passed through to form a refrigerant liquid, and the temperature of the heated hot water rises.
Next, the refrigerant liquid condensed in the condenser 26 enters the evaporator 27 maintained at a low pressure (for example, 12 to 13 mmHg in absolute pressure), and is heated by cold water passing through the evaporator 27 to a low temperature ( At 15 ° C, for example, it evaporates and becomes refrigerant vapor. Cold water lowers its temperature by heating the refrigerant. Next, evaporator 2
The refrigerant vapor evaporated in 7 enters the absorber 28 and is absorbed by the thick absorbing solution. The hot water being passed at this time is configured to be heated by the absorbing liquid that absorbs the refrigerant vapor to increase its temperature.

At this time, the return chilled water CW (R) from the chilled water utilization device of the chilled water return pipe 29 passes through the evaporator 16 of the compression refrigerator via the pump, and is sent from the chilled water feed pipe 30 as the feed chilled water CW (S). The pipe is connected so as to be sent to a cold water utilization device not shown. Further, the return hot water HW (R) from the hot water utilization device of the hot water return pipe 31 is divided into two systems, the first system passes through the condenser 14 of the compression refrigerator and the heat exchanger 17 of the engine equipment, and The second system is connected through an absorber 28 and a condenser 26 of the absorption refrigerator 24, and is connected to a pipe connection in which the two are mixed and sent as hot water HW (S) from the hot water feed pipe 25 to a hot water utilization device (not shown). Have been.

The figures in the drawing are 990.2 Nm3 / h for the engine 1 and 13 A for the auxiliary boiler 19 using city gas 13A as fuel.
When supplying 107 Nm3 / h. Naturally, these numerical values are changed by changing the fuel supply amount, adjusting the valve, and the like, and are shown as an example for easy understanding of the concept.

The heat utilization system of the present embodiment is configured as described above and operates as follows. First, city gas (13A) as fuel is supplied to the engine 1 through the flow control valve 2 at a flow rate of 990.2 Nm3 / h,
It is supplied to the auxiliary boiler 19 via the flow control valve 20 at 107 Nm3 / h. The compressor 6 is driven by the driving force, and the exhaust gas is supplied to the exhaust gas boiler 18.

When the compressor 1 is driven by the operation of the engine 1 by the supply of fuel, the refrigerant circulating inside the compression refrigerator is transferred from the compressor 13 to the condenser 14 as described above.
The refrigerating cycle of returning to the compressor 13 again through the pressure reducing valve 15 and the evaporator 16 is repeated,
Becomes low temperature.

On the other hand, the exhaust gas from the engine 1 is supplied to an exhaust gas boiler 18, and 2,400 kg / h, 60 ° C. water of 9,897 kg / h, which is supplied from a return water tank 22 by a pump 23, is supplied to the 9ata. Turn into steam. At this time, the auxiliary boiler 19 burns fuel and converts the remaining 1,497 kg / h, 60 ° C. water from the return water tank 22 into 9ata steam.

2400 kg generated by this exhaust gas boiler 18
/ h steam and 1,497 kg / h steam generated by the auxiliary boiler 19 are mixed and supplied to the absorption refrigerator 24 as 3,897 kg / h, 9ata steam, and the heat of the steam is sent to the regenerator 25. The water is supplied to become water, and collected in a return water tank (hot well tank) 22 through a steam trap 25. The recovered water is returned from the return water tank 22 by the pump 23 to the exhaust gas boiler 18 again.
And the auxiliary boiler 19. Both boilers 18, 1
As described above, the refrigerant vapor generated in the regenerator 25 by the supply and heating of the vapor from the condenser 9 is supplied to the condenser 2
6 circulates again through the evaporator 27 and the absorber 28 to the regenerator 25, and at the same time, the absorbing solution circulates through the regenerator 25 and the absorber 28. Becomes low temperature.

Accordingly, the return hot water HW (R) at 40 ° C. and 2569.8 t / h from the hot water utilization device supplied through the pipe 31
The first system (2446.1 t / h) exchanges heat with the high-temperature and high-pressure refrigerant vapor flowing inside the condenser 14 to increase the temperature from 40 ° C. to 50 ° C. In addition, jacket water 90 ° C, 5
8.1 t / h is circulated and supplied to the heat exchanger 17A, and the heat-exchanged cooling water circulates through the heat exchanger 17B.
The heat exchange in B raises the temperature from 50 ° C to 50.2 ° C.
The second system (123.7 t / h) of the return hot water HW (R) receives heat from the absorber 28 of the absorption refrigerator 24 to reduce the temperature from 40 ° C. to 57 ° C.
The temperature rises to ℃, and heat is further obtained in the condenser 26
The temperature rises from 57 ° C to 70 ° C. The hot water of the first system and the hot water of the second system are mixed and supplied to the hot water utilization device from the pipe 32 as feed hot water HW (S) having a temperature of 51.8 ° C.

Further, the return chilled water CW (R) of 13 ° C. and 2016.1 t / h from the chilled water utilization device supplied through the pipe 29 is used.
Is cooled by the evaporator 16 of the compression refrigerator,
The temperature is lowered to ° C., and the feed water CW (S) is sent out from the cold water feed pipe 30 to the cold water utilization device.

At this time, the cooling water of 30 ° C. and 150.3 t / h warmed by heat exchange in the oil cooler 5 and the air cooler 4 is cooled to 20 ° C. by the evaporator 27 of the absorption refrigerator 24, and the oil is cooled again. It is circulated and supplied to the cooler 5 and the air cooler 4.

Incidentally, the temperature of the feed chilled water CW (S) of 3 ° C. supplied from the pipe 30 to the chilled water utilization device fluctuates due to a change in load of the chilled water utilization device, a change in ambient temperature, and the like.

The feed cold water CW (S) is always kept
When it is necessary to maintain the desired set temperature of ° C., the temperature of the feed chilled water CW (S) is detected by the temperature detector 33, and the detected temperature is given to the control device 34. The amount of combustion of the engine 1 may be controlled by adjusting the opening of the flow control valve 2 of the engine 1. For example,
When the temperature of the feed chilled water CW (S) becomes higher than a predetermined value, for example, 3 ° C., the opening of the flow control valve 2 is adjusted to be larger, and the combustion of the engine 1 is controlled to be increased. Then, the temperature of the evaporator 16 drops and the temperature of the cold water becomes 3 ° C.
To keep. Conversely, when the temperature of the feed chilled water CW (S) falls below a predetermined value, for example, 3 ° C., the opening of the flow control valve 2 is adjusted to be small, and control is performed to reduce the combustion amount of the engine 1. Then, the temperature of the evaporator 16 rises, and the temperature of the cold water can be maintained at 3 ° C.

If the temperature of the cooling water in the oil cooler 5 and the air cooler 4 fluctuates, the operation of the engine 1 may be hindered. Therefore, the temperature of the cooling water (brine) used for the cooling is determined by an absorption type. The temperature is detected by the temperature detector 35 at the evaporator outlet of the refrigerator, and a control signal is sent from the control device 36 to the flow control valve 20 to control the combustion amount of the auxiliary boiler 19. For example, if the detected temperature is higher than a predetermined value, for example, 20 ° C., the opening degree of the flow control valve 20 is adjusted to be increased, and the combustion amount of the auxiliary boiler 19 is controlled to be increased.

In this embodiment, the feed hot water HW (S)
Is not performed, and if the temperature of the feed hot water HW (S) becomes low, an additional boiler (not shown) is arranged in the hot water feed pipe 32 to secure a necessary temperature.

By connecting a generator to the engine 1, it is possible to generate power according to the necessity of cold water and hot water load.

As described above, in the heat utilization system according to the present invention, the fuel is first used for motive power having a high potential and is easy to use, and then the steam is discharged from the exhaust gas boiler using the high-temperature exhaust gas in a cascade system. The compression chiller is driven using the former power, and the absorption chiller is driven using the latter steam and the auxiliary boiler steam that compensates for the shortage. Furthermore, utilizing not only cold water but also the functions of these refrigerators, heat recovery from cold water normally discarded as cooling water is recovered and used effectively for hot water, and cold water and hot water are simultaneously supplied and driven The waste heat generated by the operation of the engine, which is the source, is also used as a heat source, thereby improving the efficiency of the entire system. Of course, for this purpose, rather than simply combining, by considering the characteristics of each energy source (power, exhaust gas and waste heat), and by skillfully combining multiple types of refrigerators with the sequence of hot water and cold water, As described above, the efficiency as a whole is greatly improved for the first time.

Looking at an example of this efficiency in the embodiment, the thermal efficiency of the normal cogeneration system CGS is 43.8% for the prime mover and 35.9% for the exhaust heat recovery based on the lower heating value.
Although the total is about 79.6%, the embodiment of the present invention
Expressed as OP (a value obtained by dividing the amount of heat used by the amount of heat input), the coefficient of performance COP is 4.28. That is, the heat output (cold heat + heat) 428 can be effectively used for the input (heat input to the engine + heat input to the auxiliary boiler) 100.

[0040]

As is apparent from the above description, according to the structure of the present invention, the heat utilization system
Combining two different types of refrigerators to effectively use the engine's driving force and exhaust gas, and make up for the shortage of exhaust gas with a boiler, so that the waste heat normally radiated to the cooling water is also effectively used. By doing so, it is possible to supply cold water and hot water at the same time, and also to use waste heat generated in the engine to greatly improve the overall thermal efficiency. That is, in the present invention, the fuel is first used for motive power having high potential and is easily used, and then steam is generated in an exhaust gas boiler using high-temperature exhaust gas in a cascade system, and the compression system is used using the former motive power. It drives the refrigerator and drives the absorption refrigerator using the latter steam and the steam from the boiler to make up for the shortfall. Furthermore, utilizing not only cold water but also the functions of these refrigerators, heat recovery from cold water normally discarded as cooling water is recovered and used effectively for hot water, and cold water and hot water are simultaneously supplied and driven By using the waste heat generated by the operation of the engine as a heat source as well, the efficiency of the whole system is greatly improved. Of course, for this purpose, rather than simply combining the equipment, by taking into account the characteristics of each energy source (power and exhaust gas), and by skillfully combining multiple types of refrigerators with the sequence of hot water and cold water, For the first time, it has become possible to greatly improve the efficiency as a whole.

Then, the temperature of the chilled water supplied to the chilled water load is detected, and the amount of fuel supplied to the engine is controlled so that the temperature of the chilled water becomes a predetermined temperature. Cold water at a preset temperature can be supplied stably.

Further, by detecting the temperature of the cooling water of the engine and the temperature of the brine coming out of the evaporator of the absorption refrigerator and controlling the amount of fuel in the boiler, the operation of the engine can be stably performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a heat utilization system of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Flow control valve 3 Supercharger 4 Air cooler 5 Oil cooler 6 Jacket 7 Flow control valve 8 Flow control valve 13 Compressor 14 Condenser of compression refrigerator 16 Evaporator of compression refrigerator 18 Exhaust gas boiler 19 Auxiliary boiler 20 Flow control valve 24 Absorption chiller 25 Absorption chiller regenerator 26 Absorption chiller condenser 27 Absorption chiller evaporator 28 Absorption chiller absorber 29 Chilled water return pipe Reference Signs List 30 cold water feed pipe 31 hot water return pipe 32 hot water feed pipe 33 temperature detector 34 controller 35 temperature detector 36 controller

(72) Inventor Takao Tanaka 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Tadashi Nakajima 2-28 Nitta 2-chome, Kawanishi-shi, Hyogo

Claims (6)

[Claims] 1. A compression refrigeration system comprising: an exhaust gas boiler that generates steam using an exhaust gas of an engine as a heat source; a boiler for generating steam; and a refrigerant compressor, a condenser, a decompression device, and an evaporator driven by the engine. A regenerator, a condenser, an evaporator, and an absorber having heat generated by the steam generated by the exhaust gas boiler and the steam generated by the boiler; and the compression of the return chilled water from the chilled water utilization device. A chilled water pipe to be supplied to the chilled water utilization device after being cooled by an evaporator of the chilled refrigerator, a portion of the returned hot water from the chilled water utilization device to be heated by a condenser of the compression chiller, After mixing the rest of the hot water returned from the device with the hot water heated in order by the absorber and condenser of the absorption refrigerator, the hot water pipe to be supplied to the hot water utilization device, and the cooler for the engine is provided by the absorption type cold Machine heat utilization system, characterized by comprising a pipe cooling water circulation pipe to cool with evaporator. 2. The method according to claim 1, wherein a portion of the return hot water from the hot water utilization device is heated by a condenser of the compression refrigerator and then reheated by heat exchange with jacket cooling water of the engine. Item 2. A heat utilization system according to Item 1. 3. The heat utilization system according to claim 1, wherein the cooler for the engine is an air cooler for cooling air from a supercharger and an oil cooler for cooling oil of the engine. system. 4. The method according to claim 1, wherein a temperature of the chilled water supplied to the chilled water utilization device is detected, and an amount of fuel supplied to the engine is controlled so that the chilled water temperature becomes a predetermined temperature. The heat utilization system according to claim 1. 5. A temperature of brine that is discharged from an evaporator of the absorption refrigerator used for cooling the cooler for the engine and is detected, and a temperature of the brine supplied for cooling the cooler for the engine is predetermined. The heat utilization system according to any one of claims 1 to 4, wherein an amount of fuel supplied to the boiler is controlled so as to reach a temperature. 6. A method for controlling the amount of fuel supplied to an engine so as to detect a temperature of chilled water supplied to the chilled water utilization device to a predetermined temperature, and to cool a cooler for the engine. Detecting the temperature of the brine coming out of the evaporator of the absorption refrigerator to be used, and controlling the amount of fuel supplied to the boiler so that the temperature of the brine becomes a predetermined temperature. The heat utilization system according to any one of claims 1 to 4, wherein: