JP2010121907A - Absorption-type refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lower concentration of the absorption solution in a generator by lowering pressure of an absorber and allowing low evaporation temperature while lowering saturated solution temperature so as to lower temperature of a heating source of the generator without enlarging a device. <P>SOLUTION: The absorption-type refrigerating device, composed to feed absorption solution Lc cooled by a water-cooling type supercooling heat exchanger 2 to the absorber A, includes: a coolant reservoir 1 for storing unevaporated components of liquid coolant Rw dispersed on a heat transfer surface of an evaporator E, provided at a lower part of the evaporator E; and a cooling means X for using the liquid coolant Rw in the coolant reservoir 1 as a cooling heat source of the supercooling heat exchanger 2, for lowering the pressure of the absorber A to obtain the low evaporation temperature. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an absorption refrigeration apparatus, and more particularly to an absorption refrigeration apparatus that can lower the temperature of a heating source of a generator.

  In an absorption refrigeration apparatus (for example, LiBr absorption refrigeration apparatus), as shown in FIGS. 6 and 7, refrigerant vapor obtained by heating and concentrating a dilute solution (for example, LiBr dilute solution) with a generator G Rs is cooled and liquefied by a water-cooled condenser C, and the liquefied liquid refrigerant Rw is sprayed on the heat transfer surface of the evaporator E to cool the fluid to be cooled, and the evaporated refrigerant vapor Rs is sent to the absorber A. Then, after absorbing with the concentrated solution Lc sent from the generator G, a solution having a reduced concentration (ie, dilute solution Ld) is sent to the generator G, thereby forming an absorption cycle. Here, FIG. 6 shows an absorption cycle using the refrigerant transient type evaporator E in which the liquid refrigerant Rw from the condenser C is sprayed on the heat transfer surface from the upper part of the evaporator E. In FIG. 7, the liquid refrigerant Rw from the condenser C is supplied to the refrigerant reservoir 1 provided in the lower part of the evaporator E, and the liquid refrigerant Rw in the refrigerant reservoir 1 is transmitted from the upper part of the evaporator E by the refrigerant pump Pr. An absorption cycle using a refrigerant circulation type evaporator E circulating and sprayed on the hot surface is shown. 6 and 7, reference numeral Tc is a cooling tower, Pl is a solution pump for pumping the solution from the absorber A, Pw is a cooling water pump for pumping the cooling water Wc from the cooling tower Tc, and Ha is from the generator G. 2 is a solution heat exchanger for exchanging heat between the concentrated solution Lc and the dilute solution Ld sent to the generator G, 2 is a water-cooled supercooling heat exchanger for supercooling the absorbing solution entering the absorber A, and 5 is cooling. The cooling water circuit circulates the cooling water Wc from the tower Tc to the condenser C and the supercooling heat exchanger 2.

  Therefore, the temperature of the heating source for heating the dilute solution Ld in the generator G is from the temperature required for heat exchange with the solution temperature equal to its saturated vapor temperature at the concentration of the concentrated solution Lc at the outlet of the generator G. Will be determined. That is, since the saturated vapor temperature is the solution temperature at a pressure equal to the condensation pressure determined by the condensation temperature in the condenser C, in order to reduce the heating source temperature in the generator G, the condensation in the condenser C ( It is also reducing the pressure) temperature (see FIG. 5).

  For example, in a single-effect refrigeration system using a warm water absorption type that uses cooling water such as a gas engine, when the solution concentration in the generator G is about 60%, the saturation of the solution under the condensation pressure is assumed to be 40 ° C. The solution temperature equal to the steam temperature is 85 ° C., the heat source temperature is about 90 ° C., that is, this hot water or higher is required as the warm water for exhaust gas from the gas engine (see cycle (A) in FIG. 5). If the heat source temperature for heating the solution of the generator G can be lowered, solar heat or the like can be used as the hot water for heating, and the use range of the exhaust heat absorption refrigeration apparatus can be greatly expanded. In order to reduce the condensation temperature, it is necessary to reduce the cooling air temperature or reduce the outlet solution concentration (LiBr solution concentration) of the generator G to lower the saturated vapor temperature.

  However, in the case of a water-cooled condenser, the condensation temperature during rated operation of the absorption refrigeration apparatus is a temperature at which heat is exchanged with the cooling water in the cooling tower (cooling tower) Tc, and the temperature of the cooling water is the outside air temperature. Since the cooling water generally flows out of the absorber A and then flows into the condenser C because it is determined by the evaporation temperature at the rated time and is about 32 ° C., the condensation temperature should be 40 ° C. or lower. Is not practical because the cooling tower Tc and the condenser C need to be enlarged. Even if the cooling water flows into the absorber A and the condenser C in parallel, the condensation temperature is somewhat lowered, but the heat source temperature cannot be greatly reduced. In order to lower the heating source temperature by about 10 ° C., it is necessary to lower the condensation temperature by about 7 to 10 ° C. to 30 to 33 ° C. (see cycle (A ′) in FIG. 5).

  Moreover, reducing the heat source temperature by greatly reducing (thinning) the outlet solution (for example, LiBr solution) concentration Lc of the generator G means that the evaporation temperature in the evaporator E is equal to the inlet solution temperature of the absorber A. In order to obtain the same low chilled water temperature (that is, cooled fluid temperature), the concentration of the concentrated solution (for example, LiBr concentrated solution) Lc at the inlet of the absorber A is determined by the outlet solution concentration Lc of the generator G. Therefore, the temperature of the concentrated solution Lc at the inlet of the absorber A needs to be lowered to obtain the same evaporation temperature, and the solution temperature is inevitably determined (see the cycle (C) in FIG. 5). That is, at the low (thin) solution concentration of the generator G at a low heating source temperature, the evaporation temperature increases at the inlet solution temperature of the same absorber A (see cycle (B) in FIG. 5). The cold water temperature (cooled fluid temperature) at E cannot be lowered as prescribed, and it is difficult to simply lower the solution concentration at the generator G and lower the heating source temperature.

  As a means for lowering the temperature of the heating source of the generator, in this case, in the absorption refrigeration apparatus, two units in which an evaporator and an absorber are combined are prepared, and the absorber constituting one unit is prepared. A reflux circuit is provided to return the dilute solution from the outlet to the upper part of the absorber constituting one unit through the heat exchange part of the evaporator constituting one unit and the heat exchanging part of the absorber constituting the other unit. Thus, the temperature of the heating source of the generator can be lowered (see Patent Document 1). However, in this case, it is necessary to prepare two units in which an evaporator and an absorber are combined, and there is a demerit that the overall size of the apparatus cannot be avoided.

JP2007-271165A

  In the present invention, an unevaporated portion of the liquid refrigerant sprayed on the heat transfer surface of the evaporator is stored in a lower refrigerant reservoir, and the non-evaporated liquid refrigerant is supercooled by the refrigerant pump into the absorber. The solution is sent to the cooling heat exchanger, and the temperature of the solution at the absorber inlet is lowered by the heat exchanger for supercooling, and the pressure of the absorber is lowered, so that a low evaporation temperature can be obtained. As a result, the solution concentration in the generator can be lowered, the saturated solution temperature can be lowered, and the temperature of the heating source of the generator can be lowered.

  The present invention has been made in view of the above points, and by reducing the pressure of the absorber, enabling a low evaporation temperature, thereby reducing the concentration of the absorbing solution in the generator and lowering the saturated solution temperature. The object is to reduce the temperature of the heating source of the generator without increasing the size of the apparatus.

  In the present invention, as a first means for solving the above problems, the generator G, the condenser C that condenses and liquefies the refrigerant vapor Rs obtained from the generator G, and the liquid condensed and liquefied by the condenser C An evaporator E for evaporating and evaporating the refrigerant Rw, and a refrigerant solution Rc evaporated and evaporated by the evaporator E is absorbed in the concentrated solution Lc obtained by the generator G, and a dilute solution Ld supplied to the generator G is obtained. In the absorption refrigeration apparatus including the absorber A to be generated and configured to send the absorption solution Ld cooled by the water-cooled supercooling heat exchanger 2 to the absorber A, the lower part of the evaporator E In addition, a refrigerant reservoir 1 for storing the unevaporated liquid refrigerant Rw spread on the heat transfer surface of the evaporator E is provided, and the liquid refrigerant Rw in the refrigerant reservoir 1 is used as a cooling heat source for the supercooling heat exchanger 2. The cooling means X used as is attached.

  With the above-described configuration, the water-cooling type supercooling heat exchanger 2 that supercools the absorbing solution Ld that enters the absorber A with the unevaporated liquid refrigerant Rw sprayed on the heat transfer surface of the evaporator E. When the cooling water temperature of the absorber A is lowered and the pressure of the absorber A is lowered, a low evaporation temperature can be obtained. As a result, the solution concentration in the generator G can be lowered, the saturated solution temperature can be lowered, and the temperature of the heating source of the generator G can be lowered.

  In the present invention, as a second means for solving the above problems, in the absorption refrigeration apparatus provided with the first means, the cooling means X is used, the liquid refrigerant Rw in the refrigerant reservoir 1 is used as a refrigerant pump. It can also be constituted by the refrigerant circulation circuit 3 fed to the heat exchanger 2 for supercooling via Pr, and in such a case, a simple arrangement in which the refrigerant reservoir 1 and the refrigerant circulation circuit 3 are provided. Thus, the pressure of the absorber A can be lowered, and the evaporation temperature can be lowered.

  In the present invention, as a third means for solving the above-described problem, in the absorption refrigeration apparatus provided with the second means, the liquid refrigerant Rw in the refrigerant reservoir 1 is supplied to the refrigerant circulation circuit 3. A cooling circuit 4 for feeding the inside of the heat transfer surface of the condenser C can also be provided. In such a configuration, a part of the liquid refrigerant Rw in the refrigerant reservoir 1 is sent to the condenser C. As a result, the condensation temperature also decreases, and the temperature of the heating source of the generator G can be further decreased.

  In the present invention, furthermore, as a fourth means for solving the above problems, in the absorption refrigeration apparatus provided with the first, second or third means, exhaust heat is used as a heating source of the generator G. It can also be used, and in such a configuration, a slightly low temperature exhaust heat hot water can be used effectively.

  In the present invention, furthermore, as a fifth means for solving the above problems, in the absorption refrigeration apparatus provided with the fourth means, solar heat can also be used as the exhaust heat, and when configured as such The range of use of the absorption refrigeration apparatus can be greatly expanded.

  According to the first means of the present invention, the generator G, the condenser C that condenses and liquefies the refrigerant vapor Rs obtained from the generator G, and the liquid refrigerant Rw condensed and liquefied by the condenser C is evaporated. An evaporator A and an absorber A that absorbs the refrigerant vapor Rs evaporated by the evaporator E into the concentrated solution Lc obtained by the generator G to generate a diluted solution Ld supplied to the generator G. In an absorption refrigeration apparatus comprising the absorption solution Ld cooled by the water-cooled supercooling heat exchanger 2, the evaporator E is disposed below the evaporator E. A cooling means X is provided that stores a non-evaporated portion of the liquid refrigerant Rw sprayed on the heat transfer surface, and uses the liquid refrigerant Rw in the refrigerant pool 1 as a cooling heat source for the supercooling heat exchanger 2. Of the liquid refrigerant Rw sprayed on the heat transfer surface of the evaporator E. The evaporated component is used as a cooling heat source for the water-cooled supercooling heat exchanger 2 that supercools the absorbing solution Ld entering the absorber A, so that a low evaporation temperature can be obtained by reducing the pressure of the absorber A. Therefore, the solution concentration in the generator G can be lowered, the saturated solution temperature can be lowered, and the temperature of the heating source of the generator G can be lowered.

  As in the second means of the present invention, in the absorption refrigeration apparatus provided with the first means, the cooling means X is used for the supercooling of the liquid refrigerant Rw in the refrigerant reservoir 1 via the refrigerant pump Pr. The refrigerant circulation circuit 3 for feeding to the heat exchanger 2 can also be configured. In such a configuration, the pressure of the absorber A is reduced by a simple configuration in which the refrigerant reservoir 1 and the refrigerant circulation circuit 3 are provided. It is possible to lower the evaporation temperature.

  As in the third means of the present invention, in the absorption refrigeration apparatus provided with the second means, the liquid refrigerant Rw in the refrigerant reservoir 1 is supplied to the refrigerant circulation circuit 3 inside the heat transfer surface of the condenser C. It is also possible to attach a cooling circuit 4 to be supplied to the refrigerant. In such a configuration, a part of the liquid refrigerant Rw in the refrigerant reservoir 1 is sent to the condenser C, and the condensation temperature also decreases. As a result, the temperature of the heating source of the generator G can be further reduced.

  As in the fourth means of the present invention, in the absorption refrigeration apparatus provided with the first, second or third means, exhaust heat can be used as a heating source for the generator G, and so on. When configured, a slightly low temperature exhaust heat hot water can be used effectively.

  As in the fifth means of the present invention, in the absorption refrigeration apparatus provided with the fourth means, solar heat can also be used as the exhaust heat, and in such a case, the utilization range of the absorption refrigeration apparatus Can be greatly expanded.

  Hereinafter, several preferred embodiments of the present invention will be described with reference to the accompanying drawings.

First Embodiment FIG. 1 shows an absorption refrigeration cycle in an absorption refrigeration apparatus according to a first embodiment of the present invention.

  In this absorption refrigeration cycle, in order to recover the refrigerant absorption capacity of an aqueous solution (hereinafter simply referred to as an absorption solution) of an absorbent (for example, LiBr) having an excellent ability to absorb a refrigerant (for example, water), the solution is heated to a heating medium. A generator G for heating and concentrating with (for example, waste water), and a water-cooled condenser for liquefying by introducing steam (refrigerant) Rs separated from the solution into the generator G and cooling it. C, an evaporator E that introduces the refrigerant Rw liquefied by the condenser C and evaporates (vaporizes) under low pressure, and the generator for absorbing the vapor (refrigerant) Rs generated in the evaporator E. Absorber A spraying concentrated solution Lc concentrated in G, and again to generator G to concentrate solution (dilute solution) Ld diluted by absorbing vapor (refrigerant) Rs in absorber A Solution pump for feeding And pl, and the absorption solution Lc entering the absorber A is configured to include a heat exchanger for supercooling 2 water-cooled supercooling. Reference numeral Ha denotes a solution heat exchanger that exchanges heat between a part of the diluted solution Ld (the diluted solution Ld supplied to the generator G) exiting from the absorber A and the concentrated solution Lc that exits from the generator G, and Tc denotes cooling. The tower Pw is a cooling water pump that pumps the cooling water Wc from the cooling tower Tc to the condenser C. In this absorption refrigeration cycle, a refrigerant transient type evaporator E in which the liquid refrigerant Rw from the condenser C is sprayed from the upper part of the evaporator E to the heat transfer surface is used.

  In the absorption refrigeration cycle, the evaporator E and the absorber A are integrated to form a unit U. In the evaporator E, the condensed water (liquid refrigerant) Rw supplied from the condenser C exchanges heat with the water (cooled fluid) flowing inside, evaporates, and cold water is obtained as a heat source on the use side. On the other hand, in the absorber A, the vapor obtained from the evaporator E into the absorption solution Ld supplied from the generator G and joined with the solution from the absorber A and then supercooled by the supercooling heat exchanger 2. (Refrigerant) The solution concentration is diluted by absorbing Rs. In this case, in the absorber A, an indirect air cooling method (in other words, a solution separation cooling method) in which the absorption heat is removed by sensible heat of the supercooled absorption solution Ld simply by absorbing the refrigerant vapor Rs. .

  In the present embodiment, the lower part of the evaporator E is provided with a refrigerant reservoir 1 for accumulating the unevaporated liquid refrigerant Rw sprayed on the heat transfer surface of the evaporator E. A refrigerant circulation circuit 3 for supplying one liquid refrigerant Rw to the supercooling heat exchanger 2 via a refrigerant pump Pr is attached. The refrigerant circulation circuit 3 constitutes a cooling means X used as a cooling heat source for the supercooling heat exchanger 2.

  With the above-described configuration, the water-cooling type supercooling heat exchanger 2 that supercools the absorbing solution Ld that enters the absorber A with the unevaporated liquid refrigerant Rw sprayed on the heat transfer surface of the evaporator E. When the cooling water temperature of the absorber A is lowered and the pressure of the absorber A is lowered, a low evaporation temperature can be obtained. As a result, the solution concentration in the generator G can be lowered, the saturated solution temperature can be lowered, and the temperature of the heating source of the generator G can be lowered. That is, the heating source temperature of the generator G in the conventional absorption refrigeration apparatus (shown in FIG. 6 and FIG. 7) is equal to the evaporation temperature of the evaporator E to obtain cold water as shown in the cycle (A) of FIG. Assuming 5 ° C., about 90 ° C. was necessary. In the case of the present embodiment, as shown in cycles (B) and (C) of FIG. The heating source temperature can be set to about 80 ° C., and as the heating source of the generator G, exhaust hot water (for example, hot water by solar heat) can be used.

  However, the evaporation temperature in the cycle (A) in FIG. 5 is 5 ° C. from the saturated vapor temperature at the absorber inlet, but in the cycle (B) in FIG. 5, when the solution concentration is 56.5%, the absorber A If the inlet temperature is the same, the evaporation temperature will increase to 10 ° C.

  Therefore, in the present embodiment, as shown in the cycle (C) of FIG. 5, the evaporation temperature can be made equal to the cycle (A) by lowering the absorber inlet temperature of the cycle (B). It is doing so. The inlet temperature of the absorber A can be made lower than the cycle (C) in FIG. 5 and the solution concentration at the inlet of the absorber A can be made lower (thinner). Can be further reduced.

Second Embodiment FIG. 2 shows an absorption refrigeration cycle in an absorption refrigeration apparatus according to a second embodiment of the present invention.

  In this case, the evaporator E is a refrigerant circulation system. That is, the liquid refrigerant Rw from the condenser C merges at the outlet side of the supercooling heat exchanger 2 in the refrigerant circulation circuit 3 in which the unevaporated refrigerant in the refrigerant pool 1 circulates in the supercooling heat exchanger 2. The liquid refrigerant Rw branched from the inlet side of the supercooling heat exchanger 2 in the refrigerant circuit 3 is sprayed from the upper part of the evaporator E to the heat transfer surface. In this case, in the case of the refrigerant circulation type evaporator E, since the refrigerant reservoir 1 is already attached, the configuration can be further simplified. Since other configurations and operational effects are the same as those in the first embodiment, the description thereof is omitted.

Third Embodiment FIG. 3 shows an absorption refrigeration cycle in an absorption refrigeration apparatus according to a third embodiment of the present invention.

  In this case, the refrigerant circulation circuit 3 is provided with a cooling circuit 4 for feeding the liquid refrigerant Rw in the refrigerant reservoir 1 into the heat transfer surface of the condenser C. The cooling circuit 4 is branched on the upstream side of the supercooling heat exchanger 2 in the refrigerant circulation circuit 3. In this case, the cooling tower and the cooling water pump in the first embodiment are omitted. If it does in this way, a part of liquid refrigerant | coolant Rw of the refrigerant | coolant pool 1 will be sent to the condenser C, a condensation temperature will also fall, and the temperature of the heating source of the generator G will fall further. It becomes possible to make it. Since other configurations and operational effects are the same as those in the first embodiment, the description thereof is omitted.

Fourth Embodiment FIG. 4 shows an absorption refrigeration cycle in an absorption refrigeration apparatus according to a fourth embodiment of the present invention.

  In this case, the refrigerant circulation circuit 3 is provided with a cooling circuit 4 for feeding the liquid refrigerant Rw in the refrigerant reservoir 1 into the heat transfer surface of the condenser C. The cooling circuit 4 is branched on the upstream side of the supercooling heat exchanger 2 in the refrigerant circulation circuit 3. In this case, the cooling tower and the cooling water pump in the first embodiment are omitted. If it does in this way, a part of liquid refrigerant | coolant Rw of the refrigerant | coolant pool 1 will be sent to the condenser C, a condensation temperature will also fall, and the temperature of the heating source of the generator G will fall further. It becomes possible to make it.

  Furthermore, in this case, the evaporator E is a refrigerant circulation system. That is, the liquid refrigerant Rw from the condenser C merges at the outlet side of the supercooling heat exchanger 2 in the refrigerant circulation circuit 3 in which the unevaporated refrigerant in the refrigerant pool 1 circulates in the supercooling heat exchanger 2. The liquid refrigerant Rw branched from the inlet side of the supercooling heat exchanger 2 in the refrigerant circuit 3 is sprayed from the upper part of the evaporator E to the heat transfer surface. In this case, in the case of the refrigerant circulation type evaporator E, since the refrigerant reservoir 1 is already attached, the configuration can be further simplified. Since other configurations and operational effects are the same as those in the first embodiment, the description thereof is omitted.

  The invention of the present application is not limited to the above-described embodiments, and it goes without saying that the design can be changed as appropriate without departing from the scope of the invention.

It is an absorption refrigeration cycle in the absorption refrigeration apparatus according to the first embodiment of the present invention. It is an absorption refrigerating cycle in the absorption refrigeration apparatus concerning 2nd Embodiment of this invention. It is an absorption refrigerating cycle in the absorption refrigeration apparatus concerning 3rd Embodiment of this invention. It is an absorption refrigeration cycle in an absorption refrigeration apparatus according to a fourth embodiment of the present invention. It is a solution cycle diagram in the absorption refrigeration apparatus concerning the conventional absorption refrigeration apparatus and each embodiment of this invention. It is an absorption refrigeration cycle of a conventional indirect water-cooled absorption refrigeration apparatus equipped with a refrigerant transient type evaporator. It is an absorption refrigeration cycle of a conventional indirect water-cooled absorption refrigeration apparatus including a refrigerant circulation type evaporator.

Explanation of symbols

1 is a refrigerant reservoir 2 is a supercooling heat exchanger 3 is a refrigerant circulation circuit 4 is a cooling circuit A is an absorber C is a condenser E is an evaporator G is a generator Lc is an absorbing solution (concentrated solution)
Ld is dilute solution Pl is solution pump Pr is refrigerant pump Rs is refrigerant vapor Rw is liquid refrigerant X is cooling means

Claims (5)

  Generator (G), condenser (C) for condensing and liquefying refrigerant vapor (Rs) obtained from generator (G), and vaporizing and condensing liquid refrigerant (Rw) condensed and liquefied by condenser (C) The evaporator (E) to be evaporated and the refrigerant vapor (Rs) evaporated by the evaporator (E) are absorbed by the concentrated solution (Lc) obtained by the generator (G) and supplied to the generator (G). An absorber (A) that generates a supplied dilute solution (Ld) is provided, and the absorbent solution (Ld) cooled by the water-cooled supercooling heat exchanger (2) is sent to the absorber (A). In the absorption refrigeration apparatus configured as described above, a refrigerant reservoir for storing an unevaporated portion of the liquid refrigerant (Rw) spread on the heat transfer surface of the evaporator (E) is provided below the evaporator (E). (1) is provided, and the liquid refrigerant (Rw) in the refrigerant reservoir (1) is used as a cooling heat source for the supercooling heat exchanger (2). Absorption refrigerating apparatus characterized by annexed cooling means for use (X).   The cooling means (X) is supplied by a refrigerant circulation circuit (3) that feeds the liquid refrigerant (Rw) in the refrigerant reservoir (1) to the supercooling heat exchanger (2) via a refrigerant pump (Pr). The absorption refrigeration apparatus according to claim 1, wherein the absorption refrigeration apparatus is configured.   The refrigerant circuit (3) is provided with a cooling circuit (4) for supplying the liquid refrigerant (Rw) of the refrigerant reservoir (1) into the heat transfer surface of the condenser (C). The absorption refrigeration apparatus according to claim 2.   The absorption refrigeration apparatus according to any one of claims 1, 2, and 3, wherein exhaust heat is used as a heating source of the generator (G).   The absorption refrigeration apparatus according to claim 4, wherein solar heat is used as the exhaust heat.

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