JP4315854B2 - Absorption refrigerator - Google Patents

Description

  The present invention relates to a heat exchange device and an absorption refrigerator using the heat exchange device.

In recent years, absorption refrigerators have been required to further improve thermal efficiency from the viewpoints of energy saving and prevention of global warming. Therefore, for example, as shown in FIG. 3, not only the low-temperature heat exchanger 6 and the high-temperature heat exchanger 7 are provided in the absorption liquid pipe 13 from the absorber 5 to the high-temperature regenerator 1 through the absorption liquid pump 11. When the exhaust heat recovery heat exchangers 8X and 8Y are provided to absorb the refrigerant and reduce the absorption liquid concentration in the absorber 5 to operate the absorption liquid pump 11 and transport it to the high temperature regenerator 1, Absorption chiller 100X devised to reduce both the exhaust heat supplied from the co-generation system and the exhaust gas from the burner 1A, and the fuel burned by the burner 1A and the carbon dioxide produced during combustion Is well known (see, for example, Patent Document 1). In the figure, 2 is a low-temperature regenerator, 3 is a condenser, 4 is an evaporator, and 10 is a refrigerant pump.
JP 2000-257978 A

  In the absorption refrigerator proposed in Patent Document 1, the high-temperature absorption liquid flowing into the absorber from the low-temperature regenerator is heated by exchanging heat with the low-temperature heat exchanger, and the absorption liquid discharged from the low-temperature heat exchanger is combined with the absorption refrigerant.・ Since it was heated by exhaust heat supplied from the generation system and exhaust gas exhausted from the burner, the exhaust heat recovery heat exchanger is supplied with a hot fluid that is higher in temperature than the absorbent heated in the low-temperature heat exchanger. There is a problem that the heat source is limited. Therefore, it is necessary to provide an absorption refrigerator that can be used for improving thermal efficiency even with a thermal fluid having a lower temperature than before, and this has been a problem to be solved.

In order to solve the above problems , the present invention
Exhaust heat recovery heat exchange that exchanges heat between the diluted absorbent delivered from the absorber by the absorbent pump and the exhaust heat fluid discharged by heating the high-temperature regenerator that heats and concentrates the diluted absorbent. And
A low-temperature heat exchanger that exchanges heat between the diluted absorbent that has passed through the exhaust heat recovery heat exchanger and the concentrated absorbent that is discharged from the low-temperature regenerator and sent to the absorber;
While sequentially arranging a high temperature heat exchanger for exchanging heat between the diluted absorbent delivered by the absorbent pump and the intermediate absorbent discharged from the high temperature regenerator and sent to the low temperature regenerator,
The inlet side and the outlet side of the diluted absorbent of the above exhaust heat recovery heat exchanger are connected by a bypass pipe with a flow control valve (hereinafter referred to as a bypass control valve) interposed therebetween,
The bypass control based on the temperature obtained by detecting the temperature of the concentrated absorbent (hereinafter referred to as the discharged concentrated absorbent) discharged from the low-temperature heat exchanger and sent to the absorber. An absorption refrigerator having a first configuration, wherein the temperature of the discharged concentrated absorbent is controlled to a temperature at which the discharged concentrated absorbent is not crystallized by controlling a valve;

Instead of the control in the absorption refrigerator of the first configuration,
The bypass control based on the temperature obtained by detecting the temperature of the concentrated absorbent (hereinafter referred to as the discharged concentrated absorbent) discharged from the low-temperature heat exchanger and sent to the absorber. By controlling the valve, the temperature of the concentrated concentrated absorbent is controlled to a temperature at which the concentrated concentrated absorbent does not interfere with the refrigerant absorbing action in the absorber. The absorption refrigerator is provided.

  In the absorption refrigerator of the present invention, the refrigerant is absorbed and discharged from the absorber, and the absorption liquid before flowing into the low-temperature heat exchanger is heated in the exhaust heat recovery heat exchanger. Even a hot fluid having a lower temperature than the conventional absorption refrigerator installed downstream of the low-temperature heat exchanger can be used as a heat source for heating the absorbent.

  Moreover, since the flow rate of the absorption liquid flowing in the bypass path is controlled based on the temperature of the absorption liquid at the outlet of the low temperature heat exchanger flowing into the absorber from the low temperature regenerator, it flows into the absorber from the low temperature regenerator. The temperature of the absorbed liquid does not cause inconveniences such as (a) the absorption liquid is crystallized due to a decrease, and (b) the refrigerant is absorbed by the absorber.

  High temperature that concentrates and regenerates the absorption liquid by heating the absorption refrigerating machine that consists of piping connection of high temperature regenerator, low temperature regenerator, condenser, evaporator, absorber, low temperature heat exchanger, high temperature heat exchanger, etc. An exhaust heat recovery heat exchanger that absorbs heat from the exhaust heat fluid discharged from the regenerator and absorbs the refrigerant and discharges it from the absorber and exchanges heat with the absorption liquid before reaching the low-temperature heat exchanger is provided and discharged from the absorber. A bypass path is provided so that the absorption liquid can bypass the exhaust heat recovery heat exchanger and flow into the low-temperature heat exchanger, and the low-temperature heat of the absorption liquid flowing into the absorber from the low-temperature regenerator via the low-temperature heat exchanger. An absorption refrigerator having a control means for controlling the flow rate of the absorption liquid flowing in the bypass passage so that the temperature at the outlet side of the exchanger is slightly higher than the crystallization temperature, for example, 3 to 5 ° C.

Hereinafter, an embodiment of the present invention based on the Figures 1 and 2 will be described in detail. The absorption refrigerator 100 illustrated in the drawings is a double-effect absorption refrigerator that uses water as a refrigerant and a lithium bromide (LiBr) aqueous solution as an absorption liquid and can circulate and supply cold water to a load (not shown). .
In order to facilitate understanding, in these drawings, the same reference numerals are given to the portions having the same functions as those described in FIG.

  In the figure, 1 is a high temperature regenerator, 2 is a low temperature regenerator, 3 is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a low temperature heat exchanger, 7 is a high temperature heat exchanger, and 8 is exhaust heat recovery heat. Exchanger, 9 is a flow control valve, 10 is a refrigerant pump, 11 and 12 are absorption liquid pumps, 13 to 15 are absorption liquid pipes, 16 to 18 are refrigerant pipes, and 19 is from other equipment such as a co-generation system. A waste heat fluid supply pipe through which the exhaust heat fluid to be supplied (for example, high-temperature / high-pressure steam, high-temperature water, etc.) flows, 20 is a cold water pipe, 21 is a cooling water pipe, and is connected as shown in FIG. Has been.

  That is, the inlet side and the outlet side of the absorption liquid of the exhaust heat recovery heat exchanger 8 are connected by a bypass pipe 13A with a flow rate control valve 9 interposed therebetween, and the exhaust heat fluid supply pipe 19 is supplied from a cogeneration system or the like. First, exhaust heat fluid such as high-temperature and high-pressure steam or high-temperature water is supplied to the inside of the high-temperature regenerator 1, and the absorption liquid is heated and evaporated in the high-temperature regenerator 1 to concentrate and regenerate the absorption liquid. After radiating heat in the process, piping is provided so as to reach the exhaust heat recovery heat exchanger 8.

  Reference numeral 22 denotes a temperature sensor provided on the outlet side of the low-temperature heat exchanger 6 of the absorption liquid tube 15 for measuring the temperature of the absorption liquid that has been heat-exchanged and discharged from the low-temperature heat exchanger 6, and 23 is a temperature sensor. 22 is a controller for controlling the flow rate control valve 9 based on the temperature of the absorption liquid measured.

  In the absorption refrigerator 100 having the above-described configuration, the cooling water is supplied to the cooling water pipe 21 and supplied to the high temperature regenerator 1 through the exhaust heat fluid supply pipe 19 from a co-generation system or the like. When the exhaust heat fluid such as water is supplied and the absorption liquid is heated, the refrigerant vapor evaporated and separated from the absorption liquid and the intermediate absorption liquid in which the concentration of the absorption liquid is increased by separating the refrigerant vapor are obtained.

  The high-temperature refrigerant vapor generated in the high-temperature regenerator 1 enters the low-temperature regenerator 2 through the refrigerant pipe 16, and is generated in the high-temperature regenerator 1 through the high-temperature heat exchanger 7 via the high-temperature heat exchanger 7. The intermediate absorption liquid that has entered the condenser 2 is heated and condensed by heat dissipation, and enters the condenser 3.

  Further, the refrigerant heated by the low temperature regenerator 2 and evaporated and separated from the intermediate absorption liquid enters the condenser 3, exchanges heat with the cooling water flowing in the cooling water pipe 21 to be condensed and liquefied, and is condensed and supplied from the refrigerant pipe 16. Together with the refrigerant to be passed, it enters the evaporator 4 through the refrigerant pipe 17.

  The refrigerant liquid that has entered the evaporator 4 and accumulated in the refrigerant liquid reservoir is sprayed by the refrigerant pump 10 on the heat transfer pipe 20 </ b> A connected to the cold water pipe 20 and exchanges heat with water supplied through the cold water pipe 20. The water flowing through the heat transfer tube 20A is cooled.

Then, the refrigerant evaporated by the evaporator 4 enters the absorber 5 and is heated by the low-temperature regenerator 2 to evaporate and separate the refrigerant. The absorption liquid whose concentration of the absorption liquid is further increased, that is, the concentrated absorption liquid is the absorption liquid pipe 15. Is supplied to the absorber 5 via the low-temperature heat exchanger 6 and sprayed from above the absorber 5 to absorb the refrigerant.

  Absorbing liquid whose concentration has been reduced by absorbing the refrigerant in the absorber 5, that is, the rare absorbing liquid, is operated by operating the absorbing liquid pump 11 so that the exhaust heat recovery heat exchanger 8, the low temperature heat exchanger 6, and the high temperature heat exchanger 7 are changed. Via the absorption liquid pipe 13 to the high temperature regenerator 1 via.

  When the operation is performed as described above, the cold water cooled by the heat of vaporization of the refrigerant in the heat transfer pipe 20A piped inside the evaporator 4 can be circulated and supplied to a heat load (not shown) via the cold water pipe 20. Cooling operation such as cooling can be performed.

  And in the absorption refrigerator 100 of this invention, as shown in FIG. 2, the temperature of the absorption liquid which the temperature sensor 22 measures is only 3-5 degreeC from the crystallization temperature of the absorption liquid which is flowing through the absorption liquid pipe 15. The controller 23 controls the flow rate control valve 9 so that the flow rate control valve 9 is throttled as the measured temperature is lower and the flow rate control valve 9 is opened as the measured temperature is higher so as to maintain a high predetermined set temperature, for example, 45 ° C.

  Therefore, in the absorption refrigerator 100 of the present invention, the temperature of the absorption liquid conveyed from the absorber 5 to the high temperature regenerator 1 is not only heated by the low temperature heat exchanger 6 and the high temperature heat exchanger 7, but also discharged. Since the heat recovery heat exchanger 8 is also heated, the heating efficiency with respect to the absorbing liquid by the exhaust heat fluid such as high temperature / high pressure steam or high temperature water supplied from the co-generation system or the like via the exhaust heat fluid supply pipe 19 Is good.

  Moreover, the flow control valve 9 is opened so that the temperature of the absorbing liquid that is heated and concentrated in the low-temperature regenerator 2, dissipates heat in the low-temperature heat exchanger 6, and is supplied to the absorber 5, for example, maintains a predetermined 45 ° C. Since the temperature is controlled by the controller 23, the temperature does not decrease too much and the absorption liquid does not crystallize, and when the temperature is excessively increased and the refrigerant is absorbed by the absorber 5, it is difficult to absorb the refrigerant. Also does not happen.

  In addition, since this invention is not limited to the said embodiment, various deformation | transformation implementation is possible in the range which does not deviate from the meaning as described in a claim.

  For example, a burner as shown in FIG. 3 may be used as a heat source for heating and absorbing the absorption liquid with the high-temperature regenerator 1. When the heat source of the high-temperature regenerator 1 is set as such, the exhaust heat recovery heat exchanger 8 is supplied with high-temperature combustion exhaust gas from the burner.

  At that time, the high-temperature combustion exhaust gas discharged from the burner may be directly supplied to the exhaust heat recovery heat exchanger 8, or the low-temperature heat exchanger 6 and the high-temperature heat exchanger 7 as shown in FIG. It is also possible to configure so that the absorption liquid is heated and dissipated by an exhaust heat recovery heat exchanger separately installed between the two and then supplied to the exhaust heat recovery heat exchanger 8.

It is explanatory drawing of the absorption refrigerator of this invention. It is explanatory drawing which shows the example of control of a flow control valve. It is explanatory drawing of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High temperature regenerator 2 Low temperature regenerator 3 Condenser 4 Evaporator 5 Absorber 6 Low temperature heat exchanger 7 High temperature heat exchanger 8 Waste heat recovery heat exchanger 9 Flow control valve 10 Refrigerant pump 11, 12 Absorption liquid pump 13-15 Absorption liquid pipe 16-18 Refrigerant pipe 19 Waste heat fluid supply pipe 20 Cold water pipe 21 Cooling water pipe 22 Temperature sensor 23 Controller

Claims (2)

An exhaust heat recovery heat exchanger for exchanging heat between the diluted absorbent delivered from the absorber by the absorbent pump and the high-temperature regenerator that heats and concentrates and regenerates the diluted absorbent. When,
A low-temperature heat exchanger that exchanges heat between the diluted absorbent that has passed through the exhaust heat recovery heat exchanger and the concentrated absorbent that is discharged from the low-temperature regenerator and sent to the absorber;
While sequentially arranging a high temperature heat exchanger that exchanges heat between the diluted absorbent delivered by the absorbent pump and the intermediate absorbent discharged from the high temperature regenerator and sent to the low temperature regenerator,
Connecting the inlet side and the outlet side of the diluted absorbent of the exhaust heat recovery heat exchanger by a bypass pipe with a flow control valve (hereinafter referred to as a bypass control valve) interposed therebetween,
The bypass control valve is controlled based on the temperature obtained by detecting the temperature of concentrated absorbent (hereinafter referred to as discharged concentrated absorbent) discharged from the low-temperature heat exchanger and sent to the absorber. Thereby, the temperature of the discharged concentrated absorbent is controlled to a temperature at which the discharged concentrated absorbent does not crystallize . An exhaust heat recovery heat exchanger for exchanging heat between the diluted absorbent delivered from the absorber by the absorbent pump and the high-temperature regenerator that heats and concentrates and regenerates the diluted absorbent. When,
A low-temperature heat exchanger that exchanges heat between the diluted absorbent that has passed through the exhaust heat recovery heat exchanger and the concentrated absorbent that is discharged from the low-temperature regenerator and sent to the absorber;
While sequentially arranging a high temperature heat exchanger that exchanges heat between the diluted absorbent delivered by the absorbent pump and the intermediate absorbent discharged from the high temperature regenerator and sent to the low temperature regenerator,
Connecting the inlet side and the outlet side of the diluted absorbent of the exhaust heat recovery heat exchanger by a bypass pipe with a flow control valve (hereinafter referred to as a bypass control valve) interposed therebetween,
The bypass control valve is controlled based on the temperature obtained by detecting the temperature of concentrated absorbent (hereinafter referred to as discharged concentrated absorbent) discharged from the low-temperature heat exchanger and sent to the absorber. Accordingly, the temperature of the concentrated concentrated absorbent is controlled to a temperature at which the concentrated concentrated absorbent does not interfere with the refrigerant absorbing action in the absorber.

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