Patent Description:
Liquid sprinkling devices having the liquid dripping configuration for absorption refrigerators are conventionally known.

For example, the liquid sprinkling device described in Patent Literature <NUM> includes a tray and a guide body. The tray is long for receiving the liquid to be sprinkled. The guide body has a large number of ports for dripping provided in the longitudinal direction, and the liquid is dripped through the ports. The guide body is provided with a damming wall, and the damming wall has a long-side dam portion and a short-side dam portion. The long-side dam portion dams a long-side open end of a liquid receiving portion of the guide body. The short-side dam portion dams a short-side open end of the liquid receiving portion. Furthermore, <CIT> discloses a heat exchange unit and a method for heat exchange for an absorption refrigerator according to the preamble of independent claims <NUM> and <NUM>, respectively.

The present disclosure provides a heat exchange unit for an absorption refrigerator that is advantageous in increasing the wettability of heat transfer tubes relative to a solution having a higher viscosity than a refrigerant liquid that is inside an evaporator of an absorption refrigerator.

A heat exchange unit for an absorption refrigerator according to the present disclosure includes:.

In the heat exchange unit for an absorption refrigerator according to the present disclosure, uniform liquid films are easily formed on the second heat transfer tubes owing to the small interval between droplets of the solution to be dripped from the plurality of second portions. Therefore, the heat exchange unit for an absorption refrigerator according to the present disclosure is advantageous in increasing the wettability of heat transfer tubes relative to a solution having a higher viscosity than a refrigerant liquid that is inside an evaporator of an absorption refrigerator.

At the time when the present inventors conceived of the present disclosure, devices such as sprinkling devices and spraying devices have been devised as a technique of enhancing the liquid wettability of heat transfer tubes in absorption refrigerators. It is difficult to adapt spraying devices to absorbers of absorption refrigerators, and from the viewpoint of making components compatible with evaporators and absorbers, sprinkling devices have been generally used in both evaporators and absorbers. Under such a situation, the present inventors focused on the fact that the solution wettability of heat transfer tubes of an absorber is lower than the refrigerant liquid wettability of heat transfer tubes of an evaporator, and got an idea of configuring a drip feed in absorbers so as to specialize in dripping the solution. The present inventors found difficulty, as a problem in achieving the idea, in spreading a high-viscosity solution that is dripped and adhered to heat transfer tubes, and came to constitute the subject matter of the present disclosure to solve the problem.

Thus, the present disclosure provides a heat exchange unit for an absorption refrigerator that is advantageous in increasing the wettability of heat transfer tubes relative to a solution having a higher viscosity than a refrigerant liquid that is inside an evaporator of an absorption refrigerator.

Embodiments will be described in detail below with reference to the drawings. However, an unnecessarily detailed description may be omitted. For example, a detailed description of the matters already well known and a repeated description of substantially the same configuration may be omitted.

Embodiment <NUM> will be described below with reference to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>. In the accompanying drawings, the Z-axis negative direction represents the gravity direction. The X-axis, the Y-axis, and the Z-axis are orthogonal to each other.

As shown in <FIG>, a heat exchange unit <NUM> for an absorption refrigerator includes a first container 5a, a first heat transfer tube group 6f, a first drip feed 7a, a second container 5b, a second heat transfer tube group <NUM>, and a second drip feed 7b. The first heat transfer tube group 6f includes a plurality of first heat transfer tubes 6a arranged in rows and columns inside the first container 5a. As shown in <FIG> and <FIG>, the first drip feed 7a has a plurality of first portions 74a for dripping arranged along the longitudinal direction of the first heat transfer tubes 6a (the X-axis direction). In addition, the first drip feed 7a drips a refrigerant liquid from the first portions 74a toward the first heat transfer tube group 6f. The second heat transfer tube group <NUM> includes a plurality of second heat transfer tubes 6b arranged in rows and columns inside the second container 5b. As shown in <FIG> and <FIG>, the second drip feed 7b has a plurality of second portions 74b for dripping arranged along the longitudinal direction of the second heat transfer tubes 6b. In addition, the second drip feed 7b drips a solution from the second portions 74b toward the second heat transfer tube group <NUM>. As shown in <FIG> and <FIG>, an interval P2 between the second portions 74b adjacent to each other in the longitudinal direction of the second heat transfer tubes 6b (the X-axis direction) is smaller than an interval P1 between the first portions 74a adjacent to each other in the longitudinal direction of the first heat transfer tubes 6a.

As long as the interval P2 is smaller than the interval P1, the ratio of the interval P2 to the interval P1 (P2/P1) is not limited to a specific value.

The first drip feed 7a is disposed above the first heat transfer tube group 6f in the gravity direction. The second drip feed 7b is disposed above the second heat transfer tube group <NUM> in the gravity direction.

As shown in <FIG>, the heat exchange unit <NUM> includes, for example, an evaporator <NUM>, an absorber <NUM>, and a vapor flow path <NUM>. The heat exchange unit <NUM> is charged with a refrigerant and a solution. The evaporator <NUM> generates a refrigerant vapor. The absorber <NUM> absorbs the refrigerant vapor generated by the evaporator <NUM>. The vapor flow path <NUM> is a flow path for guiding the refrigerant vapor generated by the evaporator <NUM> to the absorber <NUM>.

The evaporator <NUM> is a shell-and-tube heat exchanger. The evaporator <NUM> is typically a sprinkling shell-and-tube heat exchanger. For example, in the case where a refrigerant, such as water, whose saturated vapor pressure at ordinary temperature (<NUM>±<NUM>) is a negative pressure is used, the water-level head of the refrigerant liquid tends to greatly influences the evaporation pressure in a flooded shell-and-tube heat exchanger. Accordingly, in the case where a refrigerant, such as water, is used, it is advantageous that the evaporator <NUM> is a sprinkling shell-and-tube heat exchanger.

The evaporator <NUM> includes the first container 5a, the first heat transfer tube group 6f, and the first drip feed 7a. The first container 5a is, for example, a container having thermal insulation properties and pressure resistance. In the first container 5a, the refrigerant liquid is stored. In addition, the first container 5a isolates the refrigerant vapor inside the first container 5a from the outside air, such as air at atmospheric pressure. In the first heat transfer tube group 6f, the plurality of first heat transfer tubes 6a are arranged in parallel to each other to define a plurality of rows in the gravity direction. The plurality of first heat transfer tubes 6a are arranged, for example, to form a square grid or a rectangular grid in a plane perpendicular to the longitudinal direction of the first heat transfer tubes 6a. The first heat transfer tube 6a is a tube made of copper or stainless steel. The first heat transfer tube 6a may have grooves in its inner surface and outer surface.

As shown in <FIG> and <FIG>, the first drip feed 7a has a tray 71a, a holder 73a, and a slit component 77a. The tray 71a has therein a storage space 70a, and a refrigerant liquid <NUM> is stored in the storage space 70a. For example, the tray 71a extends in an elongated shape in a direction parallel to the longitudinal direction of the first heat transfer tubes 6a. The tray 71a has a plurality of distribution holes 72a in its bottom portion. The plurality of distribution holes 72a are arranged, for example, along the direction parallel to the longitudinal direction of the first heat transfer tubes 6a. The holder 73a is joined to the bottom surface of the tray 71a. The holder 73a has an inclined surface just under the distribution hole 72a. In addition, the holder 73a has a lateral surface that is continuous from the inclined surface to extend toward the first heat transfer tube group 6f. An end portion of the lateral surface defines the first portion 74a. The first portion 74a is, for example, plate-like. The first portion 74a has a first pointed portion 75a that is tapered and protrudes toward the first heat transfer tube group 6f. The first pointed portion 75a has a ridge or a vertex. The first pointed portion 75a is, for example, plate-like. The slit component 77a is joined to the lateral surface of the holder 73a, and the slit component 77a and the lateral surface of the holder 73a have a drain 78a therebetween. In addition, as shown in <FIG>, the slit component 77a has an opening 76a near the first portion 74a. Thus, a plurality of openings 76a are arranged along the longitudinal direction of the first heat transfer tubes 6a.

The tray 71a, the holder 73a, and the slit component 77a each can be fabricated by, for example, pressing a stainless steel plate. The first drip feed 7a can be fabricated by welding the tray 71a, the holder 73a, and the slit component 77a.

The absorber <NUM> is a shell-and-tube heat exchanger. The absorber is typically a sprinkling shell-and-tube evaporator.

The absorber <NUM> includes the second container 5b, the second heat transfer tube group <NUM>, and the second drip feed 7b. The second container 5b is, for example, a container having thermal insulation properties and pressure resistance. In the second container 5b, the solution is stored. In addition, the second container 5b isolates the refrigerant vapor inside the second container 5b from the outside air, such as air at atmospheric pressure. In the second heat transfer tube group <NUM>, the plurality of second heat transfer tubes 6b are arranged in parallel to each other to define a plurality of rows in the gravity direction. The plurality of second heat transfer tubes 6b are arranged, for example, to form a square grid or a rectangular grid in a plane perpendicular to the longitudinal direction of the second heat transfer tubes 6b. The second heat transfer tube 6b is a tube made of copper or stainless steel. The second heat transfer tube 6b may have grooves in its inner surface and outer surface.

As shown in <FIG> and <FIG>, the second drip feed 7b has a tray 71b, a holder 73b, and a slit component 77b. The tray 71b has therein a storage space 70b, and a solution <NUM> is stored in the storage space 70b. For example, the tray 71b extends in a direction parallel to the longitudinal direction of the second heat transfer tubes 6b. The tray 71b has a plurality of distribution holes 72b in its bottom portion. The plurality of distribution holes 72b are arranged, for example, along the direction parallel to the longitudinal direction of the second heat transfer tubes 6b. The holder 73b is joined to the bottom surface of the tray 71b. The holder 73b has an inclined surface just under the distribution hole 72b. In addition, the holder 73b has a lateral surface that is continuous from the inclined surface to extend toward the second heat transfer tube group <NUM>. An end portion of the lateral surface defines the second portion 74b. The second portion 74b has a second pointed portion 75b that is tapered and protrudes toward the second heat transfer tube group <NUM>. The second portion 74b is, for example, plate-like. The second pointed portion 75b has a ridge or a vertex. The second pointed portion 75b is, for example, plate-like. The slit component 77b is joined to the lateral surface of the holder 73b, and the slit component 77b and the lateral surface of the holder 73b have a drain 78b therebetween. In addition, as shown in <FIG>, the slit component 77b has an opening 76b near the second portion 74b. Thus, a plurality of openings 76b are arranged along the longitudinal direction of the second heat transfer tubes 6b.

The tray 71b, the holder 73b, and the slit component 77b each can be fabricated by, for example, pressing a stainless steel plate. The second drip feed 7b can be fabricated by welding the tray 71b, the holder 73b, and the slit component 77b.

The vapor flow path <NUM> allows communication between the internal space of the first container 5a and the internal space of the second container 5b. In the vapor flow path <NUM>, an eliminator <NUM> is disposed. The vapor flow path <NUM> includes a portion bent by the eliminator <NUM>. This prevents the refrigerant liquid inside the first container 5a from being dragged into the flow of the refrigerant vapor and thus guided into the second container 5b.

The vapor flow path <NUM> is formed of a metal material, such as iron, having thermal insulation properties and pressure resistance. The eliminator <NUM> is fabricated by welding components shaped by pressing stainless steel plates.

The refrigerant to be charged in the heat exchange unit <NUM> is, for example, a hydrofluorocarbon (HFC)-based chlorofluorocarbon refrigerant or a natural refrigerant, such as water or ammonia. Furthermore, the solution to be charged in the heat exchange unit <NUM> is, for example, an aqueous solution of lithium bromide or an ionic fluid.

As shown in <FIG>, the heat exchange unit <NUM> further includes, for example, a first pump <NUM>, a circulation path <NUM>, a first supply path <NUM>, a second supply path <NUM>, a discharge path <NUM>, and a second pump <NUM>.

The first pump <NUM> is, for example, a dynamic canned pump. The first pump <NUM> is disposed in the circulation path <NUM>. One end of the circulation path <NUM> is connected to the first container 5a. Owing to the operation of the first pump <NUM>, the refrigerant liquid stored in the first container 5a is pumped through the circulation path <NUM>.

The first supply path <NUM> is connected to the first container 5a. The refrigerant liquid is supplied to the first container 5a through the first supply path <NUM>. The refrigerant liquid supplied to the first container 5a is guided to the first drip feed 7a. The other end of the circulation path <NUM> is connected to the first circulation path <NUM>, and the refrigerant liquid, which has passed through the circulation path <NUM>, is supplied again to the first container 5a.

The second supply path <NUM> is connected to the second container 5b. The solution is supplied to the second container 5b through the second supply path <NUM>. The solution supplied to the second container 5b is guided to the second drip feed 7b.

The discharge path <NUM> is connected to the second container 5b. The second pump <NUM> is disposed in the discharge path <NUM>. The second pump <NUM> is, for example, a dynamic canned pump. Owing to the operation of the second pump <NUM>, the solution stored in the second container 5b is pumped to the outside of the absorber <NUM>.

The circulation path <NUM>, the first supply path <NUM>, the second supply path <NUM>, and the discharge path <NUM> are each formed of, for example, a flow path member having thermal insulation properties and pressure resistance.

As for the heat exchange unit <NUM> configured as above, its operations and functions will be described below. When the heat exchange unit <NUM> is left for a specific time period, such as at night, the internal temperature of the heat exchange unit <NUM> is equal to almost room temperature and uniform, and the internal pressure of the heat exchange unit <NUM> is uniform as well. For example, at a room temperature of <NUM>, the internal temperature of the heat exchange unit <NUM> is also <NUM> and uniform. In use of the heat exchange unit <NUM>, a heat medium, such as water, that has absorbed heat from the outside of the heat exchange unit <NUM> flows through the first heat transfer tubes 6a of the first heat transfer tube group 6f. This heat medium flows into the first heat transfer tubes 6a at, for example, <NUM>. Meanwhile, a heat medium, such as water, that has dissipated heat to the outside of the heat exchange unit <NUM> flows through the second heat transfer tubes 6b of the second heat transfer tube group <NUM>. This heat medium flows into the second heat transfer tubes 6b at, for example, <NUM>.

When the use of the heat exchange unit <NUM> is started, the refrigerant liquid is first supplied into the evaporator <NUM> through the first supply path <NUM>. The refrigerant liquid to be supplied has a temperature of, for example, about <NUM>. As shown in <FIG> and <FIG>, the refrigerant liquid <NUM> supplied to the evaporator <NUM> is stored in the storage space 70a of the tray 71a of the first drip feed 7a. The refrigerant liquid <NUM> stored in the storage space 70a is distributed through the distribution holes 72a and the openings 76a, and is dripped from the first portions 74a toward the first heat transfer tube group 6f. The dripped refrigerant liquid <NUM> forms droplets <NUM>, and then flows down the outer surfaces of the first heat transfer tubes 6a to be stored in a lower portion of the first container 5a. The refrigerant liquid <NUM> stored in the lower portion of the first container 5a is pumped by the pump <NUM> to be guided again into the evaporator <NUM> through the circulation path <NUM>. Thus, the refrigerant liquid circulates inside and outside the evaporator <NUM>. In the case where an absorption refrigerator including the heat exchange unit <NUM> operates at the rated load, the refrigerant liquid <NUM> has a flow rate of, for example, about <NUM>/min and the refrigerant liquid <NUM> to be dripped by the first drip feed 7a also has an amount that is almost equal to the flow rate.

Next, the solution <NUM> is supplied to the absorber <NUM> through the second supply path <NUM>. The solution <NUM> to be supplied has, for example, a temperature of about <NUM>, a solute concentration of about <NUM> mass%, and a viscosity of about <NUM> Pa•s. The viscosity of the solution <NUM> can be about <NUM> times the viscosity of the refrigerant liquid to be supplied to the evaporator <NUM>. The solution <NUM> supplied to the absorber <NUM> is stored in the storage space 70b of the tray 71b of the second drip feed 7b. The solution <NUM> stored in the storage space 70b is distributed through the distribution holes 72b and the openings 76b, and is dripped from the second portions 74b toward the second heat transfer tube group <NUM>. The dripped solution <NUM> forms droplets <NUM>, and then flows down the outer surfaces of the second heat transfer tubes 6b to be stored in a lower portion of the second container 5b. The solution <NUM> stored in the lower portion of the second container 5b is pumped by the second pump <NUM> to be discharged to the outside of the heat exchange unit <NUM> through the discharge path <NUM>. In the case where the absorption refrigerator including the heat exchange unit <NUM> operates at the rated load, the solution <NUM>, which is to be supplied through the second supply path <NUM> and dripped by the second drip feed 7b, has a flow rate of, for example, about <NUM>/min. This flow rate is about half of the flow rate of the refrigerant liquid <NUM> in the case of the operation of the absorption refrigerator at the rated load.

When the solution <NUM> flows down the outer surfaces of the second heat transfer tubes 6b, the refrigerant vapor charged inside the heat exchange unit <NUM> is absorbed by the solution <NUM>. This increases the temperature of the solution <NUM>. On the other hand, the solution <NUM> is simultaneously cooled by the heat medium flowing through the second heat transfer tubes 6b, so that the absorption by the solution <NUM> in a supercooled state occurs continuously. This reduces the internal pressure of the heat exchange unit. Along with this, the refrigerant liquid <NUM> flowing down the outer surfaces of the first heat transfer tubes 6a evaporates. The evaporation of the refrigerant liquid <NUM> reduces the temperature of the refrigerant liquid <NUM>. However, the refrigerant liquid <NUM> is simultaneously superheated by the heat medium flowing through the first heat transfer tubes 6a, so that the evaporation of the refrigerant liquid <NUM> occurs continuously. This keeps the internal pressure of the heat exchange unit <NUM> within a predetermined range, and thus the internal state of the heat exchange unit <NUM> becomes a steady state. The refrigerant liquid <NUM> in the steady state has a temperature of about <NUM> and a viscosity of about <NUM> Pa•s. On the other hand, the solution <NUM> to be discharged from the absorber <NUM> has a temperature of about <NUM>, a solute concentration of about <NUM> mass%, and a viscosity of about <NUM> Pa•s.

The operations of the first drip feed 7a and the second drip feed 7b will be described with reference to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>.

As shown in <FIG> and <FIG>, the refrigerant liquid <NUM> supplied to the first drip feed 7a through the first supply path <NUM> is stored in the storage space 70a. The refrigerant liquid <NUM> stored in the storage space 70a flows down while being distributed through the plurality of distribution holes 72a arranged in the longitudinal direction of the tray 71a. The refrigerant liquid <NUM> is guided onto the inclined surface of the holder 73a to flow down the surface of the holder 73a. Next, the refrigerant liquid <NUM> is guided to the drain 78a to be stored again. Subsequently, the refrigerant liquid <NUM> is distributed again through the plurality of openings 76a arranged in the longitudinal direction of the tray 71a to flow down. The refrigerant liquid <NUM>, which has passed through the openings 76a, is guided to the first portions 74a to be dripped from the first pointed portions 75a of the first portions 74a. The refrigerant liquid <NUM>, which has been dripped from the first portions 74a, forms the droplets <NUM>, and then spreads over the surfaces of the first heat transfer tubes 6a and flows down while forming liquid films <NUM>.

As shown in <FIG> and <FIG>, the solution <NUM> supplied to the second drip feed 7b through the second supply path <NUM> is stored in the storage space 70b. The solution <NUM> stored in the storage space 70b flows down while being distributed through the plurality of distribution holes 72b arranged in the longitudinal direction of the tray 71b. The solution <NUM> is guided onto the inclined surface of the holder 73b to flow down the surface of the holder 73b. Next, the solution <NUM> is guided to the drain 78b to be stored again. Subsequently, the solution <NUM> is distributed again through the plurality of openings 76b arranged in the longitudinal direction of the tray 71b to flow down. The solution <NUM>, which has passed through the opening 76b, is guided to the second portions 74b to be dripped from the second pointed portions 75b of the second portions 74b. The solution <NUM>, which has been dripped from the second portions 74b, forms the droplets <NUM>, and then spreads over the surfaces of the second heat transfer tubes 6b and flows down while forming liquid films <NUM>.

<FIG> is a view schematically showing a state in which the solution <NUM> is dripped by using a drip feed 7p according to a reference example, not in accordance with the invention, instead of the second drip feed 7b. The drip feed 7p has a similar configuration to that of the first drip feed 7a.

As described above, in the present embodiment, the heat exchange unit <NUM> for an absorption refrigerator includes the first container 5a, the first heat transfer tube group 6f, the first drip feed 7a, the second container 5b, the second heat transfer tube group <NUM>, and the second drip feed 7b. The first heat transfer tube group 6f includes the plurality of first heat transfer tubes 6a arranged in rows and columns inside the first container 5a. The first drip feed 7a has the plurality of first portions 74a for dripping arranged along the longitudinal direction of the first heat transfer tubes 6a. In addition, the first drip feed 7a drips a refrigerant liquid from the first portions 74a toward the first heat transfer tube group 6f. The second heat transfer tube group <NUM> includes the plurality of second heat transfer tubes 6b arranged in rows and columns inside the second container 5b. The second drip feed 7b has the plurality of second portions 74b for dripping arranged along the longitudinal direction of the second heat transfer tubes 6b. In addition, the second drip feed 7b drips a solution from the second portions 74b toward the second heat transfer tube group <NUM>. The interval P2 between the second portions 74b adjacent to each other in the longitudinal direction of the second heat transfer tubes 6b (the X-axis direction) is smaller than the interval P1 between the first portions 74a adjacent to each other in the longitudinal direction of the first heat transfer tubes 6a.

As shown in <FIG> and <FIG>, the refrigerant liquid <NUM> to be dripped by the first drip feed 7a has a low viscosity, and also has a high flow rate. Consequently, even in the case where the interval P1 is relatively large, a favorable wettability of the first heat transfer tubes 6a relative to the refrigerant liquid <NUM> is easily achieved. On the other hand, as shown in <FIG>, in the case where the solution <NUM> is dripped by using the drip feed 7p having the same configuration as the first drip feed 7a, the liquid films <NUM> to be formed on the surfaces of the second heat transfer tubes 6b do not spread easily. This is because the viscosity of the solution <NUM> is as high as about <NUM> times the viscosity of the refrigerant liquid <NUM>. Accordingly, using the drip feed 7p increases the area of portions that do not get wet with the solution <NUM> on the surfaces of the second heat transfer tubes 6b. Consequently, it is difficult to achieve a favorable wettability of the second heat transfer tubes 6b relative to the solution <NUM>. In contrast, according to the present embodiment, since the interval P2 is smaller than the interval P1, dripping the solution <NUM> by using the second drip feed 7b reduces the interval between the droplets <NUM>. This forms the liquid films <NUM> uniformly on the surfaces of the second heat transfer tubes 6b. Consequently, a high wettability of the second heat transfer tubes 6b relative to the solution <NUM> is easily achieved.

According to the present embodiment, it is possible to provide a method for heat exchange including the following matters (I), (II), and (III).

Embodiment <NUM> will be described below with reference to <FIG> and <FIG>. A heat exchange unit according to Embodiment <NUM> has a similar configuration to that of the heat exchange unit <NUM> according to Embodiment <NUM> except portions as otherwise particularly described. A second drip feed 7c according to Embodiment <NUM> shown in <FIG> has a similar configuration to that of the second drip feed 7b except portions as otherwise particularly described. The constituent elements of the second drip feed 7c that are identical to or correspond to those of the second drip feed 7b are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. The description of Embodiment <NUM> also applies to Embodiment <NUM> unless the descriptions are technically contradictory.

As shown in <FIG>, in the second drip feed 7c, the second portions 74b each have the second pointed portion 75b that is tapered and protrudes toward the second heat transfer tube group <NUM>. The second pointed portion 75b is sharper than the first pointed portion 75a. In other words, the width of a second projection at a position away from the pointed end of the second projection by a specific distance is smaller than the width of a first projection at a position away from the pointed end of the first projection by a specific distance. The second projection is obtained by projecting, on a plane parallel to the longitudinal direction of the second heat transfer tubes 6b, the second pointed portion 75b in the direction perpendicular to the longitudinal direction of the second heat transfer tubes 6b. The first projection is obtained by projecting, on a plane parallel to the longitudinal direction of the first heat transfer tubes 6a, the first pointed portion 75a in the direction perpendicular to the longitudinal direction of the first heat transfer tubes 6a.

As for the second drip feed 7c configured as above, its operations and functions will be described below. In the case where an absorption refrigerator including the heat exchange unit <NUM> operates at about <NUM>% load, the amount of the refrigerant vapor to be generated by the evaporator <NUM> and absorbed by the absorber <NUM> is reduced by about half. On the other hand, the circulation amount of the refrigerant liquid <NUM> to be dripped by the first drip feed 7a toward the first heat transfer tube group 6f is constant independently of the load of the absorption refrigerator, and is, for example, about <NUM>/min. This is because, owing to the operation of the first pump <NUM>, the refrigerant liquid <NUM> stored in the first container 5a circulates inside and outside the evaporator <NUM> through the circulation path <NUM>. In contrast, the flow rate of the solution <NUM> to be dripped by the second drip feed 7c is determined depending on the load of the absorption refrigerator. Accordingly, in the case where the absorption refrigerator operates at about <NUM>% load, the flow rate of the solution <NUM> to be dripped by the second drip feed 7c is, for example, about <NUM>/min, which is about one-quarter of the flow rate of the refrigerant liquid <NUM>.

As shown in <FIG> and <FIG>, the solution <NUM> supplied through the second supply path <NUM> is stored in the storage space 70b. The solution <NUM> stored in the storage space 70b flows down while being distributed through the plurality of distribution holes 72b arranged in the longitudinal direction of the tray 71b. The solution <NUM> is guided onto the inclined surface of the holder 73b to flow down the surface of the holder 73b. Next, the solution <NUM> is guided to the drain 78b to be stored again. Subsequently, the solution <NUM> is distributed again through the plurality of openings 76b arranged in the longitudinal direction of the tray 71b to flow down. The solution <NUM>, which has passed through the opening 76b, is guided to the second portions 74b to be dripped from the second pointed portions 75b of the second portions 74b. At this time, the solution <NUM> flows down to be dripped in such a state as to be inscribed in the second projection of the second pointed portion 75b, for example. <FIG> and <FIG> respectively show the states of the liquid films <NUM> of the solution <NUM> as of a time t and a time t + Δt.

As described above, in the present embodiment, the second pointed portion 75b is sharper than the first pointed portion 75a. For example, in the case where an absorption refrigerator including the heat exchange unit of the present embodiment operates at about <NUM>% load, the solution <NUM> to be dripped by the second drip feed 7c has a greatly reduced flow rate. The flow rate is, for example, one-quarter of the flow rate of the refrigerant liquid <NUM> to be dripped by the first drip feed 7a, and can be half of the flow rate of the solution <NUM> to be dripped by the second drip feed 7c in the case of the rated operation of the absorption refrigerator. For example, the case will be considered where the drip feed 7p according to the reference example is used instead of the second drip feed 7c as shown in <FIG>and <FIG>. In this case, although the liquid films <NUM> spread over a wide range of the surfaces of the second heat transfer tubes 6b at the time t, the area of the surfaces of the second heat transfer tubes 6b covered with the liquid films <NUM> decreases at the time t + Δt. This can result in a temporally nonuniform wet state of the surfaces of the second heat transfer tubes 6b relative to the solution <NUM>. This is because the droplets <NUM> of the solution <NUM> have an almost equal diameter to that of the droplets <NUM> of the refrigerant liquid <NUM>, which is a relatively large diameter.

On the other hand, in the present embodiment, the second pointed portion 75b is sharper than the first pointed portion 75a, and the solution <NUM> flows down this sharper second pointed portion 75b to be dripped. Accordingly, the droplets <NUM> of the solution <NUM> have a small diameter. In the case where the second drip feed 7c and the drip feed 7p are equal in terms of the flow rate of the solution <NUM>, the second drip feed 7c has a shorter time interval of dripping the solution <NUM>. In other words, the solution <NUM> is continuously dripped toward the second heat transfer tube group <NUM> in a temporally uniform state. This suppresses the temporal nonuniformity of the wet state of the solution <NUM> on the surfaces of the second heat transfer tubes 6b even in the case where the absorption refrigerator including the heat exchange unit of the present embodiment operates at about <NUM>% load with a small flow rate of the solution <NUM>. Accordingly, the liquid films <NUM> can be formed favorably on the surfaces of the second heat transfer tubes 6b.

Embodiment <NUM> will be described below with reference to <FIG>.

As shown in <FIG>, an absorption refrigerator <NUM> includes the heat exchange unit <NUM>. The absorption refrigerator <NUM> further includes, for example, a regenerator <NUM> and a condenser <NUM>. The absorption refrigerator <NUM> is, for example, an absorption refrigerator of the single-effect cycle.

As for the absorption refrigerator <NUM> configured as above, its operations and functions will be described below. The solution <NUM> stored in the second container 5b is guided to the regenerator <NUM> through the discharge path <NUM>. In the regenerator <NUM>, the solution <NUM> is heated to increase the solute concentration. The solution <NUM> with the increased solute concentration is guided to the absorber <NUM> through the second supply path <NUM>. Meanwhile, the heating of the solution <NUM> in the regenerator <NUM> generates a refrigerant vapor. This refrigerant vapor is guided to the condenser <NUM>, and is cooled to be condensed in the condenser <NUM>. Thus, a refrigerant liquid is generated. For example, the refrigerant liquid is reduced in pressure and then is guided to the evaporator <NUM> through the first supply path <NUM>.

As described above, in the present embodiment, the absorption refrigerator <NUM> includes the heat exchange unit <NUM>. In the heat exchange unit <NUM>, the liquid films <NUM> of the solution <NUM> are uniformly formed on the surfaces of the second heat transfer tubes 6b, easily increasing the wettability of the second heat transfer tubes 6b relative to the solution <NUM>. Accordingly, the coefficient of performance (COP) of the absorption refrigerator <NUM> is easily increased.

As described above, Embodiments <NUM>, <NUM>, and <NUM> have been described as exemplary techniques disclosed in the present application. However, the technique according to the present disclosure is not limited to these, and is also applicable to embodiments with modifications, replacements, additions, omissions, and the like. Furthermore, it is also possible to combine the constituent elements described in Embodiments <NUM> and <NUM> above to achieve a new embodiment. Thus, other embodiments will be exemplified below.

In Embodiment <NUM>, as one configuration example of the first drip feed 7a, the description has been given on the configuration in which the tray 71a, the holder 73a, and the slit component 77a are included. The first drip feed 7a only needs to be capable of dripping the refrigerant liquid from the plurality of first portions 74a toward the first heat transfer tube group 6f. Accordingly, the first drip feed 7a is not limited to the configuration in which the tray 71a, the holder 73a, and the slit component 77a are included. However, in the case where the first drip feed 7a has such a configuration, the refrigerant liquid is easily distributed in the longitudinal direction of the first heat transfer tubes 6a.

In Embodiments <NUM> and <NUM>, as one configuration example of the second drip feeds 7b and 7c, the description has been given on the configuration in which the tray 71b, the holder 73b, and the slit component 77b are included. The second drip feeds 7b and 7c only need to be capable of dripping the solution from the plurality of second portions 74b toward the second heat transfer tube group <NUM>. Accordingly, the second drip feeds 7b and 7c are not limited to the configuration in which the tray 71b, the holder 73a, and the slit component 77a are included. However, in the case where the second drip feeds 7b and 7c have such a configuration, the solution is easily distributed in the longitudinal direction of the second heat transfer tubes 6b.

In Embodiments <NUM> and <NUM>, the first portions 74a have been described as having the first pointed portions 75a, which are tapered and protrude toward the first heat transfer tube group 6f, and the second portions 74b have been described as having the second pointed portions 75b, which are tapered and protrude toward the second heat transfer tube group <NUM>. The first portions 74a and the second portions 74b only need to be capable of dripping the refrigerant liquid and the solution, respectively. Accordingly, the first portions 74a and the second portions 74b do not need to have the first pointed portions 75a that are tapered and the second pointed portions 75b that are tapered, respectively. However, in the case where the first portions 74a have the first pointed portions 75a that are tapered, the diameter of the droplets of the refrigerant liquid to be dripped from the first portions 74a is easily adjusted to a desired size. In addition, in the case where the second portions 74b have the second pointed portions 75b that are tapered, the diameter of the droplets of the solution to be dripped from the second portions 74b is easily adjusted to a desired size.

In Embodiments <NUM> and <NUM>, the first portions 74a and the second portions 74b both have been described as being plate-like. The first portions 74a and the second portions 74b only need to be capable of dripping the refrigerant liquid and the solution, respectively. Accordingly, the first portions 74a and the second portions 74b are not limited to be plate-like. However, in the case where the first portions 74a and the second portions 74b are plate-like, the first portions 74a and the second portions 74b are easily fabricated. The first portions 74a and the second portions 74b may be conical or pyramidal, and may have a hollow structure.

In Embodiment <NUM>, the description has been given on an absorption refrigerator of the single-effect cycle as one example of the absorption refrigerator <NUM>. The absorption refrigerator <NUM> only needs to include the heat exchange unit <NUM>. Accordingly, the absorption refrigerator <NUM> is not limited to an absorption refrigerator of the single-effect cycle. The absorption refrigerator <NUM> may be an absorption refrigerator of the double-effect cycle or the triple-effect cycle. In the case where a gas burner is used as the heat source for the regenerator <NUM>, the absorption refrigerator <NUM> can be a gas chiller.

Claim 1:
A heat exchange unit (<NUM>) for an absorption refrigerator, comprising:
a first container (5a);
a first heat transfer tube group (6f) including a plurality of first heat transfer tubes (6a) arranged in rows and columns inside the first container (5a);
a first drip feed (7a) having a plurality of first portions (74a) for dripping arranged along a longitudinal direction of the first heat transfer tubes (6a), the first drip feed being configured to drip a refrigerant liquid from the first portions toward the first heat transfer tube group (6f);
a second container (5b);
a second heat transfer tube group (<NUM>) including a plurality of second heat transfer tubes (6b) arranged in rows and columns inside the second container (5b); and
a second drip feed (7b) having a plurality of second portions (74b) for dripping arranged along a longitudinal direction of the second heat transfer tubes (6b), the second drip feed being configured to drip a solution from the second portions toward the second heat transfer tube group (<NUM>),
characterised in that
an interval between the second portions (74b) adjacent to each other in the longitudinal direction of the second heat transfer tubes (6b) is smaller than an interval between the first portions (74a) adjacent to each other in the longitudinal direction of the first heat transfer tubes (6a).