JPH0722371U - Absorption refrigeration equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the initial cost and running cost of an absorption refrigeration system by adopting a compact and highly efficient reheater that has a small amount of retained solution. In an absorption type refrigerating apparatus including an evaporator 6 and a reheater 1 for heating and concentrating a dilute solution which has absorbed a refrigerant vapor generated in the evaporator, an upper header 30 and a lower portion which are independently configured A header 31, a burner 25 for injecting a combustion gas containing flame in a substantially horizontal direction, and a large number of substantially vertical arrangements that are connected between the headers and intersect the combustion gas, and that are arranged relatively densely. Solution tubes 22a, 23
a, 24a, and at least the upstream solution pipe group is provided with the reheater 1 having a solution pipe group arranged in the combustion flame portion.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an absorption refrigeration system including an evaporator and a reheater for heating and concentrating a dilute solution that has absorbed refrigerant vapor generated in the evaporator.

[0002]

[Prior art]

 The conventional direct-fire reheater of this type of absorption refrigerating apparatus is generally of a smoke tube type, or a water tube type as disclosed in Japanese Patent Publication No. 6-14271.

[0003]

[Problems to be solved by the device]

 Such a furnace tube smoke tube type or tube water tube type reheater has a large amount of retained solution, and when the retained solution amount is large, when a high cost solution such as lithium bromide (LiBr) is used as the solution (absorption liquid). However, there was a problem that the initial cost and running cost of the device would be high. The purpose of the present invention is to reduce the initial cost and running cost of the absorption refrigeration system by adopting a compact and highly efficient reheater with a small amount of retained solution.

[0004]

[Means for Solving the Problems]

 The present invention relates to an absorption refrigeration system that includes an evaporator and a reheater that heats and concentrates a dilute solution that has absorbed refrigerant vapor generated in the evaporator. A burner for injecting a combustion gas containing a flame in a substantially horizontal direction, and a large number of substantially vertical lines that are connected between the headers and intersect the combustion gas, and are arranged relatively densely. It is characterized in that the reheater is provided with a solution tube group including at least an upstream solution tube group composed of a solution tube and arranged in the combustion flame section.

[0005]

According to the above means, the portion of the reheater that encloses the solution is mainly the header and the solution pipe group, and furthermore, the structure in which the water pipe group is directly heated by the flame ejected from the burner is adopted. Therefore, a highly efficient and compact structure can be achieved, and the amount of retained solution is greatly reduced as compared with the conventional furnace tube smoke tube type or furnace tube water tube type.

[0006]

【Example】

 An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a refrigeration cycle of the same embodiment, FIG. 2 is a cross-sectional view of a main part of the same embodiment, and FIG. 3 is a front view of a main part of the same embodiment with a part cut away.

In FIG. 1, 1 is a reheater which will be described later, 2 is a lift pipe, 3 is a separator, 4 is a condenser, 5 a and 5 b are heat exchangers, 6 is an evaporator, 7 is an absorber, 8 Is a refrigerant U-shaped pipe, 9 is a cooling water pipe, 10 is a cold water pipe, 11a and 11b are concentrated solution pipes, 12a and 12b are dilute solution pipes, and 13 is a pressure adjusting pipe. In order to explain the basic operation of the absorption refrigerating apparatus having such a configuration, the refrigerant vapor rising from the reheater 1 to the pumping pipe 2 and the concentrated solution are separated by the separator 3, and the concentrated solution is heat-exchanged via the conduit 11a. While exchanging heat with the dilute solution through the concentrated solution portion 5a, it flows into the absorber 7 through the conduit 11b, falls onto the cooling water pipe 9, and gradually descends to the lower stage while absorbing the refrigerant vapor. . On the other hand, the refrigerant vapor separated by the separator 3 is condensed by the condenser 4 to become water, which flows into the evaporator 6 through the refrigerant U-shaped tube 8 and drops on the cold water pipe 10 to sequentially It re-evaporates and cools the surroundings while descending to the lower stage. The solution that has absorbed the refrigerant vapor and becomes a dilute solution flows into the dilute solution portion 5b of the heat exchanger through the conduit 12a, exchanges heat with the concentrated solution, and then enters the reheater 1 again through the conduit 12b to be heated and condensed. Be done. After that, this cycle is repeated.

Next, the structure of the reheater 1 will be described with reference to FIGS. 2 and 3. This reheater 1 has a structure similar to a can body in a square multi-tube type once-through boiler, and a solution tube wall 21 forming the outer shell thereof has straight tube-shaped vertical solution tubes 21a arranged at equal intervals. The adjacent vertical solution pipes 21a are connected to each other by the fin-shaped member 26 so that the space between the vertical solution pipes 21a is closed to form a rectangular wall member. It is configured. As a result, the solution tube wall 21 defines the outer shell of the can body and also has a function as a heat transfer surface. Therefore, the solution pipe wall 21 has a structure in which a region where the heat transfer coefficient decreases due to the decrease in the gas flow velocity, that is, a so-called dead water region is not formed. This will ensure a sufficient effective heat transfer area and will greatly contribute to the improvement of thermal efficiency.

Then, two solution tube walls 21 configured as described above are faced to each other while maintaining a required space therebetween, and are arranged so as to be substantially parallel to each other, forming a pair of solution tube walls 21. , 21 respectively constituting the vertical solution pipes 21a, 21a, ... The lower header 31 is connected to the heat exchanger 5b of FIG. 1, and the upper header 30 is connected to the separator 3 so that LiBr as a solution can be filled up to the middle of the lower header 31, the solution tube group 30 and the upper header 30. Is filled. As shown in FIG. 3, the upper and lower headers 30 and 31 in this embodiment are independent from each other in the upper and lower sides, and are independent from each other in the longitudinal direction of the solution tube wall 21. The upper header 30 and the lower header 31 are connected to each other by an external pipe (not shown) or the like, and are integrated. Of course, the upper and lower headers may be configured with one head (not shown) instead of the left and right independently.

A burner 25 such as a premix burner is provided at one end of the pair of solution tube walls 21, 21 in the longitudinal direction, and an exhaust gas outlet 18 is provided at the other end. . As a result, the pair of solution tube walls 21 and 21 and the upper and lower headers 30 and 31 form a gas passage 29 through which combustion gas containing flame from the burner 25 passes substantially linearly. There is.

In the gas passage 29, a large number of vertical solution pipes 22a, 22a, ..., 23a, 23a, ..., 24a, 24a, ... Are provided at intervals that allow the flow of combustion gas from the burner 25. Has been inserted. At this time, the interval between the vertical solution tubes 22a, 23a, 24a should be set as narrow as possible in order to improve the convective heat transfer efficiency between the combustion gas and the vertical solution tubes 22a, 23a, 24a. Although it is preferable, if it is extremely narrow, the gas flow velocity around each vertical solution pipe 22a, 23a, 24a becomes too fast, resulting in a large pressure loss. Conversely, if it is extremely wide, the gas flow velocity becomes slow and the convective heat transfer efficiency described above is increased. And the number of vertical solution pipes 22a, 23a, 24a to be inserted must be reduced, which reduces the heat transfer area and therefore the heat transfer amount itself. In this respect, the distance (gap) between the vertical solution tubes 22a, 23a, 24a is equal to or smaller than the diameter of the vertical solution tubes (22a, 23a, 24a), as shown in FIG. As a result, the arrangement density is densely configured.

The respective vertical solution pipes 22a, 23a, 24a are inserted and installed over almost the entire area of the gas passage 29 while maintaining the above intervals. In this way, the upper and lower ends of the vertical solution pipes 22a, 23a, 24a, which are inserted over almost the entire area of the gas passage 29, have the vertical solution pipes 21a, 21a constituting the two solution pipe walls 21, 21. , ..., are connected to the upper and lower headers 30 and 31, respectively. Further, the vertical solution pipe 22a facing the burner 25 is arranged at a position relatively close to the burner 25, and the interval between the burner 25 and the vertical solution pipe 22a facing the burner 25 is also extremely small. It is small.

Of the vertical solution tubes 22a, 23a, 24a inserted in the gas passage 29, the vertical solution tubes adjacent to the pair of solution tube walls 21, 21 are as shown in FIG. , And the vertical solution tubes 21a, 21a, ... Forming the two solution tube walls 21, 21 are arranged in a staggered arrangement. With such an arrangement, the lateral width of the solution pipe assembly 40 formed by the both solution pipe walls 21 and 21, the headers 30 and 31, and the vertical solution pipes 22a, 23a, and 24a ( The width in the left-right direction in FIG. 2) can be reduced.

According to the solution pipe assembly 40 configured as described above, the flow path of the combustion gas from the burner 25, that is, the gas passage 29 can be linearly formed as a relatively long one. It takes a relatively long time for the combustion gas to pass through the rearmost vertical solution pipe 24a. That is, the residence time of the combustion gas in the solution tube assembly 40 becomes relatively long, and the combustion gas is sequentially convected to the vertical solution tubes 21a, 22a, 23a, 24a in the gas passage 29. It produces heat, which causes its temperature to gradually decrease. Therefore, there is no locally high temperature in the entire gas passage 29, so that the generation of NO _X , especially thermal NO _X can be suppressed more effectively, and the oxidized CO ₂ becomes CO due to thermal dissociation. Will never be generated again.

Now, further explaining the embodiment shown in FIG. 2, the vertical solution tubes 22a, 23a, 24a are arranged in two rows along the longitudinal direction between the solution tube walls 21, 21. A predetermined number of the vertical solution pipes are arranged from the burner 25 side toward the exhaust gas outlet 28 side at equal intervals, and the vertical solution pipes of each are a bare pipe 22a, a finned pipe 23a, and an erofin pipe 24a from the upstream side. . Each of the vertical solution tubes 22a, 23a, 24a constitutes three solution tube groups 22, 23, 24 having different heat transfer surface densities, and these first to third solution tube groups 22, 23, 24 are formed. In the gas passage 29, the heat transfer surface density (heat transfer surface area per unit flow path length of combustion gas) decreases from the burner 25 side toward the exhaust gas outlet 28 side. They are arranged in the order of

In the reheater 1 configured as described above, the combustion gas containing the flame ejected from the burner 25 flows through the gas passage 29 in the first solution pipe group 22 composed of the bare pipe 22 a, with fins. It passes through the second solution pipe group 23 composed of the pipe 23a and the third solution pipe group 24 composed of the erofin pipe 24a while conducting convective heat transfer, and flows out from the exhaust gas outlet 28. Therefore, as described above, the combustion gas has a high temperature and a large volume on the upstream side, but on the downstream side, the temperature decreases due to the convective heat transfer to each of the vertical solution tubes 22a, 23a, 24a, and the volume of the combustion gas decreases and is transferred. Thermal efficiency is also reduced. However, since the heat transfer surface density is increased on the downstream side, the heat transfer amount in each of the vertical solution pipes 22a, 23a, and 24a extends from the upstream vertical solution pipe 22a to the downstream vertical solution pipe 24a. The temperature of the combustion gas also gradually decreases.

The combustion gas from the burner 25 continues the combustion reaction in the upstream side, that is, the first solution tube group 22 with the presence of flame, and in the middle, that is, the second solution tube group 23 and the third solution tube group 2 In 4, the flame was extinguished, and the combustion reaction was almost completed and became exhaust gas. As a result, in the first solution tube group 22 having a low heat transfer surface density on the upstream side, the temperature of the combustion gas accompanied by the presence of the flame is kept low, so that NO _X , particularly thermal NO _X is generated. It will be suppressed more effectively. Further, in the second solution tube group 23 and the third solution tube group 24 having a large heat transfer surface density on the downstream side, the temperature of the combustion gas gradually decreases, so that the oxidized CO ₂ is converted into CO ₂ by thermal dissociation. Since CO is not generated again, the generation of CO is suppressed even more effectively. In addition, since there is no locally high temperature in the entire gas passage 29, the solution can be heated relatively uniformly, and metal corrosion due to the solution (lithium bromide) caused by the local temperature rise can be prevented.

The present invention is not limited to the above embodiment, but the structure of the reheater 1 includes an upper header and a lower header which are configured independently of each other, and a combustion including a flame in a substantially horizontal direction. A burner for injecting gas and a large number of substantially vertical solution pipes connected between the both headers and arranged in a direction intersecting with the combustion gas and having a relatively dense arrangement density, and at least an upstream solution pipe group As long as it has a solution tube group arranged in the combustion flame section. As the reheater, a plurality of reheaters having the structures shown in FIGS. 2 and 3 may be installed in parallel and the number of operating units may be controlled according to the load. Furthermore, the refrigeration cycle of the absorption refrigeration system is not limited to the one shown in FIG. 1, and ammonia may be used as the solution.

[0019]

[Effect of device]

 According to the present invention configured as described above, the portion of the reheater that encloses the solution is the upper header and the lower header and the solution pipe group that connects them, and the water pipe group is formed by the flame ejected from the burner. Since the structure that directly heats the furnace is adopted, a highly efficient and compact structure can be achieved, and the amount of liquid retained is greater than that of the conventional furnace tube smoke tube type or reactor tube water tube type. Significantly reduced, and significant effects such as a significant reduction in initial cost and running cost required for the solution of the absorption refrigeration system.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a refrigeration cycle according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of the same embodiment.

FIG. 3 is a front view of the main part of the same embodiment with a part broken away.

[Explanation of symbols]

 1 Reheater 6 Evaporator 21a, 22a, 23a24a Solution pipe 30 Upper header 31 Lower header

Claims (1)

[Scope of utility model registration request] 1. An absorption refrigerating apparatus comprising an evaporator and a reheater for heating and concentrating a dilute solution that has absorbed a refrigerant vapor generated in the evaporator, an upper header and a lower header which are configured independently of each other. A burner for injecting combustion gas containing a flame in a substantially horizontal direction, and a large number of substantially vertical solutions connected between the headers and intersecting with the combustion gas, and arranged relatively densely. An absorption type refrigerating apparatus, comprising: a reheater having a tube and at least an upstream solution tube group having a solution tube group arranged in a combustion flame portion.