JPH063330B2 - Absorption chiller / heater generator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an absorption chiller-heater used for air conditioning and the like, and relates to a generator of the absorption chiller-heater suitable for a heat exchanger for combustion gas and solution. .

[Conventional technology]

As a generator for an absorption chiller-heater, a once-through boiler type generator has the advantages that it has a smaller amount of solution storage than a full-filling type generator, and as a result has good starting characteristics. For example, as shown in Japanese Patent Laid-Open No. 58-150780, a combustor that emits a downward flame is arranged in the center of a heating tube wound in a coil shape to improve thermal efficiency.

Further, in Japanese Utility Model Laid-Open No. Sho 58-196746, the heat exchanger body is formed by a plate member and side plates that close the ends of these members, and fins that are vertically spaced at regular intervals on the inner surface are inclined upward. In addition, the combustion gas from the burner installed in the lower part of the main body is sucked by the fan installed in the upper part and the heat is absorbed by the fins, and the expanded pipe is held in the cylindrical holding part provided on the outer surface of the plate member. There is disclosed a heat exchanger adapted to heat the refrigerant flowing in the formed pipe.

Further, in Japanese Patent Laid-Open No. 57-87575, an exhaust port is provided in the upper part of the outer cylinder, a baffle plate is provided in the bottom part, an inner cylinder is built in the inner cylinder, and an empty space communicating with the opening is provided outside the inner cylinder. A chamber is formed, a spiral copper pipe is attached to the outer peripheral wall of the inner cylinder, the outside of the outer cylinder is surrounded by a cooling cylinder to provide a cooling chamber between the two, an air intake port at the bottom and an inner cylinder at the top. There is disclosed a hot water boiler in which a combustor having a burner facing the above is attached, and the combustor communicates with an upper part of a cooling chamber through a pipe.

[Problems to be Solved by the Invention]

However, in the conventional technique described in JP-A-58-150780, since the heating pipe is wound in a circular spiral shape, the area of the combustion gas flow passage in the central portion of the heating pipe is widened, and the combustion gas flow velocity becomes slow. The efficiency of heat transfer to the heating tube is poor, and the length of the heat transfer tube that surrounds the flow path of the combustion gas is short, which increases the number of spiral stages, increasing the height of the once-through boiler, and increasing the size. There were some drawbacks such as large size.

Also, since the solution boiling in the heat transfer tube flows along the circular spiral flow path, it is pushed outward due to centrifugal force, and the flow rate decreases at the inside where heat from the combustion gas flows in. However, there is a drawback that local overheating tends to occur.

Further, in the heat exchanger disclosed in Japanese Utility Model Laid-Open No. 58-196746, the heat transfer tube is formed of a relatively long straight line portion and a curved portion,
The heat transfer tube is provided on the outer surface of the outer wall, and the flow direction of the combustion gas and the flow direction of the refrigerant are the same,
No consideration was given to making the heat load uniform in the part where the combustion gas temperature drops.

Further, the hot water boiler disclosed in JP-A-57-87575 is configured so that the combustion gas flows from the top to the bottom and the solution to be heated flows from the bottom to the top, but the heat of the portion where the combustion gas temperature decreases No consideration was given to equalizing the load.

The object of the present invention is to reduce the size of the once-through boiler type generator, and to even out the local heating of the heat transfer tube to make the heat load uniform, and to achieve a small size with high thermal efficiency, durability, and highly reliable absorption. The purpose is to provide a regenerator for a hot and cold water heater.

[Means for Solving the Problems] In order to achieve the above object, the regenerator of the absorption chiller-heater of the present invention has a heat transfer tube having a plurality of winding stages and fins through which a solution flows, An outer wall surrounding the heat transfer tube,
A combustor attached to the outer wall is provided, and combustion gas of the combustor is configured to flow in the outer wall, and a solution inlet of the heat transfer tube is located at a position distant from the combustor.
In a generator of an absorption chiller-heater in which a solution outlet of the heat transfer tube is provided at a close position, the heat transfer tube is formed in a linear shape with a relatively long straight portion and a curved portion, The heat transfer tube has a baffle plate for forming a combustion gas passage on the inner side surrounded by, and for preventing the combustion gas from blowing through at least one winding stage downstream in the solution flowing direction from the solution inlet. It is characterized in that fins are provided on the heat transfer tubes before and after the baffle plate on the inflow side of the solution, and the heat transfer tube on the outflow side is a bare tube.

[Action]

In the regenerator of the absorption chiller-heater of the present invention, the heat transfer tube is formed in a long and slender linear shape composed of a relatively long straight portion and a curved portion,
By making the combustion gas flow passage surrounded by these heat transfer pipes elongated, the heat transfer pipe length per combustion gas flow passage area can be made longer than that of the heat transfer pipe wound in a circular spiral shape. The length of the heat transfer tube is increased, the overall height is decreased, and the size can be reduced. Further, the combustion gas and the solution are used as an ideal counterflow for the heat exchanger to improve the heat exchange efficiency, and a fin tube is used as a heat transfer tube to increase the fin height on the downstream side where the combustion gas temperature becomes low, By reducing the fin pitch and providing a baffle for preventing gas blow through at the center of the spiral heat transfer tube, the heat load distribution can be made uniform and the overall size can be reduced. Furthermore, since the centrifugal force does not work on the solution in the straight pipe part of the spirally wound heat transfer tube, the solution easily wraps around the heat transfer surface inside the spiral tube where heat from the combustion gas flows in, causing local overheating. You can avoid it.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In FIGS. 1 and 2, 1 is a combustor that discharges a line-shaped flame downward, 2a, 2b, 2c, and 2d are arranged in the lower part of the combustor 1, and the heat transfer tubes are wound in an elliptical spiral shape. 2a is a bare tube, 2b is a fin tube having a low fin height and a low density, 2c is a fin tube having a high fin height and a low density, and 2d is a fin tube having a high fin height and a high density. Reference numeral 3 denotes an outer wall surrounding the heat transfer tube 2 having an elliptical spiral shape, 4 a combustion chamber having an elongated columnar shape formed inside the heat transfer tube 2, and 5 a blow-through of a combustion gas installed downstream of the combustion chamber. Is a baffle, 7 is an inlet solution, 8 is an outlet solution and generated steam, 9 is a combustion gas emitted downward, and 10 is an exhaust gas.

In this embodiment, as described above, the heat transfer tube 2 is wound into an elliptical spiral shape consisting of a straight line portion and a semicircular portion, and the heat transfer tube 2 is fitted into the combustion chamber 4 of an elongated cylinder formed inside the spiral heat transfer tube. Since the combustor 1 having a line-shaped flame is used, the heat transfer efficiency can be improved and the overall size can be reduced as compared with the circular spiral heat transfer tube. For example, if the combustion gas passage area is the same,
The circumference of a circular spiral heat transfer tube is shorter than the circumference of an elliptical spiral heat transfer tube. To secure the same heat transfer area, the number of winding steps increases and the overall size increases. Become. Alternatively, when the heat transfer tube is formed in a circular spiral shape with the same length of the heat transfer tube for one round, the combustion gas passage area becomes wide, the gas flow velocity becomes slow, and the heat transfer coefficient on the combustion gas side decreases. However, a large transmission area is required, leading to a larger size. In order to prevent this, even if the baffle is installed in the center of the combustion chamber and the flow rate of the combustion gas is increased to make the number of stages of the heat transfer tubes the same, the volume of the baffle portion is large and the generator becomes large. Further, an expensive heat resistant material is required as a material for the baffle exposed to a high temperature of about 1000 ° C.

Further, in the circular spiral heat transfer tube, as shown in FIG. 3, centrifugal force acts on the solution 11 flowing inside to push the solution outward, so that the heat from the combustion gas 9 flows into the spiral heat transfer tube 2. Although liquid runs out on the inner heat transfer surface and local heating occurs, the solution inside the straight heat transfer tube is not subjected to centrifugal force as shown in Fig. 4, and the heat transfer surface on the combustion gas side with the highest heat load Even so, the solution can sufficiently wrap around and prevent the occurrence of local heating.

Further, in the present embodiment, since the counter flow is such that the combustion gas is flown from the top to the bottom and the solution is flowed from the bottom to the top, the heat transfer efficiency can be improved, and the convection effect that the density of the liquid becomes small and naturally rises can be utilized.

Further, as the combustion gas temperature decreases, fins are provided on the heat transfer tube, the fin height is increased toward the downstream side of the combustion gas, the fin pitch is made finer, and the combustion gas is blown through to the most downstream part where the combustion gas temperature is low. By providing the baffle for preventing, the heat load of the heat transfer tube can be made uniform, local heating can be prevented, and the overall size can be reduced.

Further, in this embodiment, since the heat transfer tube is formed by one,
Since there is no welding seam inside the combustion chamber, there is an effect that reliability against leakage and corrosion is improved.

Further, since the outer wall is arranged in contact with the bare tube, there is an advantage that high temperature combustion gas does not blow through and the wall can be prevented from overheating.

Next, another embodiment of the present invention will be described with reference to FIG.

Reference numeral 1 denotes a gun-type combustor having a cylindrical relatively long flame, 4 denotes a combustion chamber surrounded by a water cooling wall 6 from which the flame of the combustor 1 blows from the lateral direction, and 6 denotes a heat transfer tube 2 surrounding the combustion chamber 4 It is a water-cooling wall for the solution and the generated vapor to flow in and complete the evaporation. Since the other structure is the same as that of the embodiment shown in FIG. 1, its explanation is omitted.

In the present embodiment configured as described above, the flame of the gun-type burner 1 having a cylindrical flame is blown laterally to the combustion chamber 4 surrounded by the water cooling wall 6 and is arranged under the combustion chamber 4. It also eliminates the need for bending the elliptical spiral heat transfer tube, which simplifies production and improves reliability.

Next, another embodiment of the present invention will be described with reference to FIG.

Reference numeral 13 is a pipe joint for connecting heat transfer pipes having different diameters, and the other structure is the same as that of the embodiment shown in FIGS.

In the present embodiment configured as described above, the same effects as those in FIG. 1 and FIG. 2 are obtained, and the pipe diameter of the upstream side of the solution is reduced by using the pipe joint so that the boiling progresses and the two-phase flow occurs. Since the diameter of the pipe on the downstream side which becomes the flow is made thick, there is also an effect that the heat transfer coefficient inside the pipe can be improved and the overall size can be reduced without increasing the pressure loss.

〔The invention's effect〕

As described above, in the present invention, the heat transfer tube is formed in the shape of a long slender line composed of a relatively long straight portion and a bent portion, and the flow path of the combustion gas surrounded by these heat transfer tubes is formed into a long thin shape. At the same time, the flow of the combustion gas is from top to bottom, and the flow of the solution is from bottom to top, and the fins are installed in the heat transfer tube as the temperature of the combustion gas decreases. Since the fin pitch is made finer and a baffle that prevents blow-through of combustion gas is provided in the center of the combustion gas flow path surrounded by the spiral heat transfer tube, the once-through boiler type generator is configured. The overall shape is slim and the height is low, so it can be miniaturized.

(2) Local heating can be prevented to improve durability and reliability.

(3) The efficiency is improved by making the heat load uniform.

[Brief description of drawings]

1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. FIG. 3 is a diagram showing the flow of the solution in the conventional heat transfer tube, and FIG. 4 is a diagram showing the flow of the solution in the heat transfer tube of the present invention. FIG. 5 is a vertical sectional view of another embodiment of the present invention, and FIG. 6 is a vertical sectional view of another embodiment of the present invention.
FIG. 7 is a sectional view taken along the line AA in FIG. 6, and FIG. 8 is a longitudinal sectional view showing another embodiment of the present invention. 1 ... Burner, 2 ... Heat transfer tube, 3 ... Outer wall, 4 ... Combustion chamber, 5
... baffle, 6 ... water cooling wall, 7 ... inlet solution, 8 ... outlet solution, 9 ... combustion gas, 10 ... exhaust gas, 11 ... solution, 12 ...
Header, 13 ... Pipe fitting.

Claims (3)

[Claims] 1. A heat transfer tube having a plurality of winding stages and having fins through which a solution flows, an outer wall surrounding the heat transfer tube, and a combustor attached to the outer wall. While being configured to flow inside the outer wall, the solution inlet of the heat transfer tube is located at a position distant from the combustor, and the solution outlet of the heat transfer tube is provided at a position close to the absorption chiller-heater. In the generator, the heat transfer tube is formed in a linear shape with a relatively long straight portion and a bent portion to form a combustion gas passage inside the heat transfer tube, and the solution is introduced from an inlet of the solution. A baffle plate for preventing blow-through of the combustion gas is provided on the downstream side of at least one winding stage in the flowing direction inside the heat transfer tube, and the heat transfer tubes before and after the baffle plate on the inlet side of the solution are provided. A fin is installed on the Generator of an absorption chiller-heater is characterized in that the heat pipe and bare tube. 2. The generator for an absorption chiller-heater according to claim 1, wherein the combustion gas is caused to flow from above and the solution to be heated is caused to flow from below to above. 3. The absorption type chiller-heater according to claim 1, wherein the fins of the heat transfer tube are higher in height and denser in pitch toward the downstream side of the combustion gas. vessel.