JP3400699B2 - Absorption chiller / heater using engine exhaust heat - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cogeneration system capable of generating electricity and heating and cooling at the same time, and more particularly to an absorption chiller-heater utilizing engine exhaust heat for recovering engine exhaust heat in an absorption chiller-heater and utilizing it for cooling and heating.

[0002]

2. Description of the Related Art A conventional device introduces engine exhaust gas into a high-temperature regenerator to form a double-effect absorption cycle to improve thermal efficiency, and hot water from a jacket is introduced into a low-temperature regenerator to absorb a single-effect absorption. It constituted a cycle and performed a refrigerating action.

As another device, the engine exhaust gas and the engine jacket outlet cooling hot water are heat-exchanged to recover all the exhaust heat of the engine as hot water, and cold water is produced using a single-effect low-temperature water absorption refrigerator. was there.

A related technique of this type is disclosed in Japanese Patent Laid-Open No. 7-218017.

[0005]

In the above apparatus, since the exhaust gas of the engine is utilized in the double-effect absorption cycle having high thermal efficiency, the refrigerating capacity that can be taken out from the exhaust heat of the engine is large, but it flows out from the high temperature regenerator. Exhaust gas temperature is 2
No consideration was given to the fact that the temperature was about 00 ° C and the amount of exhaust heat recovered was small.

Also, in the other device described above, since the engine exhaust gas and the hot water of about 90 ° C. are heat-exchanged, heat can be recovered until the outlet temperature of the exhaust gas reaches about 120 ° C., but the amount of exhaust heat recovery increases. No consideration was given to the fact that the absorption refrigerator has a single-effect cycle and the thermal efficiency is low and the refrigerating capacity is smaller than that of the refrigerator.

The present invention introduces engine exhaust gas into a high temperature regenerator to utilize heat in a double-effect absorption cycle, increase refrigeration capacity, and recover the amount of heat recovered from the exhaust gas by heating the exhaust gas and hot water. It is an object of the present invention to provide an engine exhaust heat utilization absorption chiller-heater that maximizes the thermal efficiency of a cogeneration system by making it equal to or more than when replaced.

The above-mentioned object is an absorption type cold / hot water in which a high temperature regenerator, a low temperature regenerator, a condenser, an absorber, a low temperature heat exchanger and a high temperature heat exchanger which utilize exhaust gas of an engine are operatively connected by piping. Machine and an exhaust gas introduction means for introducing exhaust gas to the high-temperature regenerator, in an absorption chiller-heater using exhaust heat of the engine, jacket cold-hot water that cools the engine is exhaust gas on the exhaust gas outlet side of the high-temperature regenerator. A heat exchanger for exchanging heat with the engine, and a hot water return pipe for returning hot water to the engine without passing the heat exchanger between the engine and the heat exchanger, the heat exchanger being provided downstream of the heat exchanger with the hot water. Bypass pipes are provided for returning the hot water whose temperature has been lowered by heat exchange to the engine without passing through the low temperature regenerator.A jacket hot water temperature controller is provided at the branch of the hot water return pipe.
The hot water temperature controller works to flow into the heat exchanger.
Preventing temperature drop of the temperature adjusting means in the bypass pipe provided, engine from the low temperature generator in said temperature regulating means
So that the temperature of the hot water flowing back to the jacket is kept constant
It is achieved by controlling the.

[0009]

[0010]

A pipe for returning hot water to the engine jacket is provided by bypassing the absorption chiller / heater from the hot water outlet side of the heat exchanger of exhaust gas and hot water, and a device for controlling the hot water temperature not to fall too low is provided. Thus, the temperature of the heat transfer surface on the gas side of the heat exchanger of the exhaust gas and the hot water is maintained above the dew condensation temperature of the exhaust gas.

[0012]

FIG. 1 shows an embodiment of the present invention.

In FIG. 1, 1 is an evaporator, 2 is an absorber,
3 is a condenser, 4 is a low temperature regenerator, 5 is a high temperature regenerator, 6 is a low temperature heat exchanger, 7 is a high temperature heat exchanger, 8 is a refrigerant pump, 9 is a solution pump, 10 is an exhaust gas / hot water heat exchanger. , 11 is an exhaust gas pipe, 12 is a jacket cooling hot water pipe, 13 is a hot water three-way valve, 14 is a hot water temperature controller, 15 is a hot water pump, 1
6 is an engine, 17 is a generator, 18 is hot water bypass piping, 19 is cold / hot water, 20 is cooling water, and 21 is a jacket cooling hot water temperature controller.

Exhaust gas from the engine 16 is exhaust gas pipe 11
The diluted solution introduced into the high temperature regenerator 5 through the absorber is heated and the refrigerant solution (water vapor) is generated from the solution to concentrate the solution. The refrigerant vapor generated in the high temperature regenerator 5 is guided to the low temperature regenerator 4 to heat the dilute solution sent from the absorber 2 to generate refrigerant vapor and concentrate the solution, a so-called double-effect absorption cycle. It acts to increase the thermal efficiency of the absorption cycle and increase the refrigeration capacity.

When the exhaust gas of the engine 16 is introduced into the high temperature regenerator 5, the thermal efficiency of the absorption cycle is increased and the refrigeration capacity is increased as described above, but the solution temperature in the high temperature regenerator is 15%.
Since the temperature is 0 to 160 ° C, the exhaust gas outlet temperature is 200
The temperature is only about 0 ° C., and when a high quality gas such as city gas is used as the fuel for the engine 16, the heat can be further recovered.

The exhaust gas flowing out of the high temperature regenerator 5 is introduced into the exhaust gas / hot water heat exchanger 10 for exchanging heat with the jacket cooling hot water of the engine 16, and the heat is further recovered from the exhaust gas,
The exhaust gas temperature is set to about 120 ° C. and the gas is discharged. By mounting the exhaust gas / hot water heat exchanger 10 on the exhaust gas outlet of the high temperature regenerator 5 as described above, about 50
Exhaust gas of 0-600 ℃ up to about 200 ℃ High temperature regenerator 5
Utilizing heat in a double-effect cycle at 200 ℃ to 120 ℃
By recovering the heat as hot water and utilizing the heat in the single-effect cycle, it is possible to increase the exhaust heat recovery amount of the engine 16 and increase the refrigeration capacity. The jacket cooling hot water of the engine 16 has an engine inlet temperature of 80 to 83 ° C and an engine outlet temperature of 8
Since it is as low as 5 to 90 ° C, when it is used in an absorption chiller / heater,
Unless the heat transfer area of the absorption chiller-heater is large, heat cannot be transferred and a large-scale absorption chiller-heater is required. The average temperature difference between the hot water and the solution at this time is set to about 8 to 10 ° C. If such jacket cooling hot water is further heated by the exhaust gas, the temperature rises by 2 to 3 ° C and can be supplied to the low temperature regenerator 4 of the cold / hot water machine, so that the average temperature difference between the hot water and the solution increases by 1 to 2 ° C, and the absorption cold temperature is increased. The heat transfer area of the water machine can be reduced by about 20%,
The chiller / heater can be downsized.

The exhaust gas of the engine 16 contains a large amount of moisture and carbon dioxide gas, and when the exhaust gas is cooled to about 60 ° C., the moisture in the exhaust gas condenses and adheres to the heat transfer surface as water droplets. The carbon dioxide gas in the exhaust gas melts into the water droplets to become carbonated water, and the heat transfer surface of the heat exchanger is severely corroded. Therefore, the temperature of the heat transfer surface of the exhaust gas heat exchanger must be maintained at a temperature at which water does not condense. On the other hand, the solution temperature of the cold / hot water machine has a characteristic that the solution temperature of the low-temperature regenerator is significantly lowered when the refrigeration load is lowered or the cooling water temperature is lowered, and the hot water temperature for heat exchange with the solution is also greatly lowered. In such a case, the jacket hot water temperature controller 21 works on the jacket side of the engine and the hot water temperature does not drop significantly, but this reaction tends to lower the hot water temperature on the exhaust gas / hot water heat exchanger side. .

As a measure for preventing the above, the outlet hot water of the exhaust gas / hot water heat exchanger 10 is returned to the engine jacket side via the hot water bypass pipe 18 and the hot water three-way valve 13, and the temperature of the hot water returned to the engine jacket is kept constant. As described above, the temperature controller 14 opens and closes the three-way valve 13 to bypass the low temperature heat exchanger 4. By controlling in this way, the heat transfer surface temperature of the exhaust gas / hot water heat exchanger 10 can be maintained at a temperature higher than the temperature at which the water content of the exhaust gas condenses, so that the corrosion of the exhaust gas / hot water heat exchanger 10 is prevented. This enables stable operation over a long period of time.

[0019]

According to the present invention, the heat of the exhaust gas of the engine can be efficiently provided and the amount of recovered heat can be maximized, so that the refrigerating capacity is significantly increased. Further, since the temperature of the heat transfer surface through which the exhaust gas passes can be maintained above the temperature at which the water content of the exhaust gas condenses, the life of the heat exchanger is extended and stable operation can be performed for a long period of time.

[Brief description of drawings]

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

[Explanation of symbols]

1 ... Evaporator, 2 ... Absorber, 3 ... Condenser, 4 ... Low temperature regenerator, 5 ... High temperature regenerator, 6 ... Low temperature heat exchanger, 7 ... High temperature heat exchanger, 8 ... Refrigerant pump, 9 ... Solution pump 10 ... Exhaust gas / hot water heat exchanger, 11 ... Exhaust gas pipe, 12 ... Jacket cooling hot water pipe, 13 ... Hot water three-way valve, 14 ... Hot water temperature controller, 15 ... Hot water pump, 16 ... Engine 17 ... Generator , 18 ... Hot water bypass piping, 19 ... Cold / hot water, 20 ... Cooling water, 21 ... Jacket hot water temperature controller.

Front Page Continuation (72) Inventor Kunio Yazawa 3-4-1, Shibaura, Minato-ku, Tokyo Inside NTT FACILITIES CORPORATION (72) Inventor Fukumitsu 3-4-1, Shibaura, Minato-ku, Tokyo Incorporated in NTT Facilities (72) Inventor Koji Kiyokawa 3-4-1, Shibaura, Minato-ku, Tokyo Incorporated in NTT Facilities (56) Reference JP-A-7-218019 ( JP, A) JP-A-8-233391 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 27/02 F25B 15/00 303

Claims (2)

(57) [Claims] Claims: 1. An absorption chiller-heater which uses an engine exhaust gas to operatively connect a high temperature regenerator, a low temperature regenerator, a condenser, an absorber, a low temperature heat exchanger, and a high temperature heat exchanger. In an absorption chiller-heater using engine exhaust heat, which comprises exhaust gas introduction means for guiding exhaust gas to the high-temperature regenerator, the jacket chilled water that has cooled the engine is exhausted from the exhaust gas and heat to the exhaust gas outlet side of the high-temperature regenerator. The heat exchanger to be exchanged, between the engine and this heat exchanger, the hot water return pipe that returns hot water to the engine without passing through this heat exchanger Bypass pipes are provided to return the hot water whose temperature has been lowered to the engine without passing through the low temperature regenerator, and to the branch part of the hot water return pipe.
This jacket hot water is equipped with a jacket hot water temperature controller.
The temperature flowing into the heat exchanger due to the function of the temperature controller
Prevent deterioration, a temperature adjusting means provided in the bypass pipe,
From the low temperature regenerator to the engine jacket by the temperature control means.
An absorption chiller-heater using exhaust heat from an engine, which is controlled to keep the temperature of the hot water flowing back to the tank constant . 2. A pre-Symbol temperature adjustment means, the engine waste heat utilization according to claim 1, characterized in that to control the temperature of the gas-side heat transfer surface of the heat exchanger above condensation temperature of the exhaust gas Absorption chiller / heater.