JP2010281553A - Hot air generating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot air generating device for saving a space, easily recovering a refrigerating machine oil of a compressor even when it is mixed in a refrigerant circulation passage, and easily performing a maintenance and inspection work in safety. <P>SOLUTION: In this hot air generating device in which a heat pump cycle is constituted by connecting a compressor 22, a gas cooler 24, an expansion valve, and plate type heat exchangers (water heat source evaporators) 32a, 32b in series on the refrigerant circulation passage, and circulating a refrigerant to these devices, and the air is supplied to the gas cooler 24 to rise a temperature of the air by heat exchange with the refrigerant to generate hot air, a mount 16 is disposed while surrounding a space including the compressor 22 and the plate-type heat exchangers 32a, 32b, the gas cooler 24 is disposed on the mount 16, the gas cooler 24 includes a plurality of fins disposed in parallel with each other, and an inlet header and an outlet header disposed at an inlet side and an outlet side of the plurality of fins, and the inlet header and the outlet header are vertically disposed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a hot-air generator, and more particularly to a hot-air generator that forms a heat pump cycle using CO ₂ as a refrigerant, generates air by raising the temperature by exchanging air with a gas cooler and exchanging heat with the refrigerant. Is.

  When drying wood, marine products, industrial parts, etc., it is known to dry using hot air. In order to generate hot air, it is necessary to heat air, and an electric heater, a steam heater, or the like is used as an air heating source.

  However, as described above, when an electric heater or a steam heater is used as an air heating source, the entire equipment is enlarged, and a considerable amount of time is required to control the heating of air to a predetermined temperature. If hot air is required, the time is lengthened. In addition, when trouble such as disconnection occurs in the electric heater, the steam heater, and its peripheral devices, the repair work is complicated and the time required for the repair becomes long.

In addition, as a hot air generator that can change low-temperature energy to high-temperature energy without using the electric heater, the steam heater, or the like, a device that generates hot air using a heat source that constitutes a heat pump cycle has also been proposed. Yes. For example, in Patent Document 1, a compressor, a heat exchanger between refrigerants, an expansion valve, and an evaporator are sequentially connected to constitute a refrigerant circuit as a supercritical heat pump cycle in which a CO ₂ refrigerant circulates, A refrigerant heat exchanger, a fan convector, and a hot water pump for circulating hot water are sequentially connected to form a hot water circulation circuit, and the inside of the fan con vector body is divided into a main air flow path and a sub air flow path, An auxiliary radiator in which a main radiator and a main blower fan are provided in the main air flow path, and one end of the auxiliary air flow path is connected to the hot water outflow pipe and the other end is connected to the outflow side of the main radiator. And an auxiliary blower fan, and a hot air generator that cools in two stages by releasing heat of hot water with the main radiator and the auxiliary radiator is disclosed.

JP 2007-40627 A

However, in the technique disclosed in Patent Document 1, heat is exchanged between the refrigerant CO ₂ and hot water in the inter-refrigerant heat exchanger to warm the hot water, and hot air is generated using the warmed hot water. As a result, the number of equipment increases and the equipment becomes larger. Further, no particular contrivance has been made for the arrangement of the devices constituting the heat pump cycle, and even if the technique disclosed in Patent Document 1 is applied as it is, space saving is difficult. Furthermore, in the case of the technique disclosed in Patent Document 1, if each device constituting the heat pump cycle is housed in a narrow space such as in the housing in order to save space, the worker is placed in the narrow space in the housing. There is a problem that maintenance and inspection work becomes difficult because the hands are out of reach.

Also, since not been devised for the arrangement of the equipment, if the refrigerating machine oil such as a lubricating oil of the compressor mixed in CO ₂ refrigerant circuit, it is difficult to recover the refrigerating machine oil.

  Therefore, in view of the problems of the prior art, the present invention is a hot air generator that generates hot air by passing air through a gas cooler that constitutes a heat pump cycle, and can save space and constitute a heat pump cycle. It is an object of the present invention to provide a hot air generator that can be easily recovered even if the lubricating oil of the compressor to be mixed is mixed in the refrigerant circulation path, and that allows maintenance and inspection work of the constituent devices to be performed safely and easily.

In order to achieve this object, in the present invention,
A compressor, a gas cooler, an expansion valve, and a water heat source evaporator are connected in series on the refrigerant circulation path to form a heat pump cycle that circulates the refrigerant through these devices, and air is passed through the gas cooler to generate heat from the refrigerant. A hot air generator that generates hot air by raising the temperature by replacement, and includes a base that surrounds the space including the compressor and the water heat source evaporator, and the gas cooler is disposed on the base, and the gas coolers are arranged in parallel And a plurality of tubes disposed on the inlet side and the outlet side of the plurality of tubes, and the inlet header and the outlet header are arranged vertically.

In the hot air generator of the present invention, the heat exchange between the refrigerant and the air eliminates the need for interposing warm water between the heat exchange between the refrigerant and the air as in the technique disclosed in Patent Document 1, The number of points can be reduced, and the space can be saved.
In addition, by arranging the gas cooler above the space including the compressor and the heat exchanger via a gantry, the floor area on which the hot air generator is arranged can be reduced, and space saving can be achieved.

  Further, since the gas cooler is arranged on the gantry, when refrigeration oil such as compressor lubricating oil is mixed in the refrigerant, the refrigeration oil does not accumulate in the tube forming the gas cooler and is lowered by gravity. It becomes easy to fall into. Furthermore, since the inlet header and the outlet header are arranged vertically, the refrigerating machine oil that comes out together with the refrigerant from the plurality of tubes easily falls downward due to gravity. Therefore, the refrigerating machine oil mixed in the refrigerant falls downward due to gravity, and can be circulated through the refrigerant circulation path together with the refrigerant and recovered to the compressor.

  The gas cooler is a plate fin tube type gas cooler including a plurality of fins through which the plurality of tubes pass, and the plurality of tubes are arranged in a plurality of rows along a direction in which the air passes. And a plurality of tubes arranged in the vertical direction in each of the plurality of rows, each of the plurality of fins being divided from a plurality of divided fins divided along the direction in which the air flows. The divided fins may be configured such that the tubes of the number of rows equal to or more than the divided fins positioned on the downstream side of the air flow pass through the direction in which the air passes through the divided fins.

In particular, the divided fins located on the most downstream side of the air flow should be penetrated by only one row of tubes. For example, when the gas cooler has 36 rows of tubes, the number of rows of tubes that penetrate in order from the upstream of the air flow is 5 rows, 5 rows, 5 rows, 5 rows, 5 rows, 5 rows, 2 rows, 1 row, 1 row. One row and one row can be eleven divided fins.
In the gas cooler, as it goes downstream of the air flow, the temperature of the refrigerant flowing through the air and the tube is high, and the temperature of the air approaches the target hot air temperature. By constituting the fin from a plurality of divided fins, heat transfer between the divided fins can be prevented even in the same fin. Therefore, as the air flows downstream, the number of tubes passing through the divided fins is reduced, that is, the width of the divided fins in the air flow direction is reduced so that the air temperature is close to the target hot air temperature. The hot air temperature can be stabilized.
Furthermore, the higher the temperature of the refrigerant flowing through the air and the tube, the larger the thermal expansion of the divided fins, but the smaller the width of the divided fins in the larger thermal expansion region, the influence of deformation due to thermal expansion, The influence of thermal distortion can be kept small.

Further, the compressor is arranged near one side surface of the space surrounded by the gantry and can be pulled out of the space, and the water heat source evaporator is arranged near the side surface facing the one side surface. It may be configured to be drawable out of the space.
With the above configuration, during maintenance and inspection work, the compressor is pulled out of the space from one side of the space surrounded by the frame, and the water heat source evaporator is pulled out of the space from the side facing the one side. be able to. Accordingly, since it is possible to draw the device out of the space using the two surfaces, the maintenance and inspection work can be facilitated and the space required for the maintenance and inspection work can be saved.

  Further, if the water heat source evaporator is composed of a plurality of plate heat exchangers arranged in parallel, the water heat source evaporator can be made compact without reducing the necessary capacity.

The refrigerant is CO _2, at the outlet side of the compressor CO ₂ is preferable to configure the heat pump cycle as a supercritical state. As a result, it is possible to produce hot air having a wide range of uses exceeding 90 ° C. with a gas cooler with high efficiency. Moreover, the refrigeration oil recovery by the gas cooler is further facilitated.

  According to the present invention, a hot air generator that generates hot air by passing air through a gas cooler that constitutes a heat pump cycle, can save space, and the lubricating oil of the compressor that constitutes the heat pump cycle is a refrigerant. It is possible to provide a hot air generator that can be easily collected even if it is mixed in the circulation path, and that allows maintenance and inspection work of the component equipment to be performed safely and easily.

It is a flow sheet of a hot air generator concerning an example. It is a side view of the hot air generator which concerns on an Example. It is a schematic plan view of the hot air generator which concerns on an Example. It is a perspective view of the gas cooler which concerns on an Example.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

FIG. 1 is a flow sheet of the hot air generator according to the embodiment. An outline of the operation of the hot air generator according to the embodiment will be described with reference to FIG.
In FIG. 1, the compressor 22 is provided with an inverter device 104 that controls the rotational speed of the compressor 22. The compressor 22 is operated so that the CO ₂ refrigerant discharged from the compressor 22 is in a supercritical state at high temperature and high pressure exceeding the critical pressure and critical temperature of CO ₂ . The CO ₂ refrigerant temperature in the supercritical state may be set to a temperature that is higher by about 10 to 15 ° C. than the desired hot air temperature. For example, when hot air at 120 ° C. is required, the CO ₂ refrigerant temperature is set to 130 to It should be 135 ° C. The supercritical CO ₂ refrigerant reaches the gas cooler 24 from the compressor discharge-side refrigerant flow path 100, where it is cooled by air and condensed. The air introduced into the gas cooler may be outside air or air of about 30 to 50 ° C. that is used and heated in other parts of the factory.

The air supplied to the gas cooler 24 is heated by exchanging heat with the supercritical CO ₂ refrigerant, and becomes hot air having a temperature of about 80 to 120 ° C. The temperature of the hot air can be adjusted by adjusting the temperature of the supercritical CO ₂ refrigerant as described above. The hot air is discharged from the gas cooler 24 and sent to the user. The air inlet to the gas cooler 24 and the hot air outlet from the gas cooler 24 are connected to the air supply source and the hot air supply destination using a duct or the like.

  On the outlet side of the gas cooler 24, the refrigerant channel 100 branches into the branch channel 102. The refrigerant flow path 100 branches to the branch flow path 102, and further branches into two branch flow paths 100a and 100b. Expansion valves 106a and 106b are interposed in the branch flow paths 100a and 100b, respectively. The branch flow paths 100a and 100b are connected to the plate heat exchangers 32a and 32b on the downstream side of the expansion valves 106a and 106b.

The plate-type heat exchangers 32a and 32b are supplied with heat source water that provides an evaporation heat source for the CO ₂ refrigerant from the heat source water supply pipe 36 through branch pipes 36a and 36b. The heat source water is, for example, ground water, or waste water used in a factory. The CO ₂ refrigerant flowing through the branch flow paths 100a and 100b is decompressed by the expansion valves 106a and 106b, and exchanges heat with the heat source water by the plate heat exchangers 32a and 32b to obtain latent heat of evaporation and evaporate. The evaporated CO ₂ refrigerant flows into the refrigerant flow paths 100c and 100d on the outlet side of the plate heat exchangers 32a and 32b, and is further returned to the compressor 22. On the other hand, the heat source water exiting the plate heat exchangers 32a and 32b is discharged to the heat source drain pipe 38 through the branch pipes 38a and 38b.
In order to improve the coefficient of performance (COP), the CO ₂ in the refrigerant channel 100 and the refrigerant channels 100c and 100d before joining the branch channel 100a and 100b after exiting the gas cooler 24 are merged. A heat exchanger for exchanging heat with CO ₂ in the refrigerant flow path 100 before returning to the compressor 22 may be provided.

A part of the CO ₂ refrigerant discharged from the gas cooler 24 is diverted to the supercritical tanks 26 a and 26 _b through the branch flow path 102. Two supercritical tanks are provided, and one or two of them can be used. Thereby, a part of refrigerant | coolant amount which flows through a refrigerant circuit can be stored in the supercritical tank 26a, 26b. In this way, by providing a supercritical tank and adjusting the amount of refrigerant flowing through the refrigerant circulation path, the degree of superheat at the compressor inlet and the discharge gas at the compressor outlet can be maintained even when operating conditions such as outside air temperature fluctuate. Reduces temperature and pressure fluctuations and enables stable supercritical heating operation. Further, by providing two supercritical tanks, it is possible to cope with the generation of warm air in a wide temperature range. Further, in the hot air generator, the CO ₂ filling amount increases in order to cope with the generation of hot air in a wide temperature range. When the hot air generator is stopped, the expansion valves 106a and 106b are closed, the electromagnetic valve 108 is opened, and a pump-down operation for collecting the CO ₂ refrigerant in the supercritical tank is performed. The CO ₂ refrigerant recovery to the supercritical tank by pumping down manages the pressure in the apparatus against the fluctuation of the ambient temperature around the hot air generator while the equipment other than the supercritical tank is stopped.

The outlet side branch channel 102 of the supercritical tank 26 is connected to the outlet side branch channel 100b of the expansion valve 106b. Note that the outlet side branch channel of the supercritical tank 26 is branched into two branch channels, and the two branch channels are connected to the outlet side branch channels 100a and 100b of the expansion valves 106a and 106b, respectively. May be.
Further, solenoid valves 108 and 110 for adjusting the flow rate are provided on the upstream side and the downstream side of the refrigerant tank 26 so that the amount of refrigerant flowing into the supercritical tank 26 is adjusted by the upstream side flow rate adjusting valve 108 and the downstream side. The amount of refrigerant flowing out of the supercritical tank 26 is adjusted by the side flow rate adjustment valve 110.

In FIG. 1, a temperature sensor 112 is provided in the inlet side refrigerant flow path 100 of the compressor 22. Further, a pressure sensor 128 is provided in the discharge side refrigerant flow path 100 of the compressor 22. The temperature of the temperature sensor 112 and the pressure of the pressure sensor 128 are input to the controller 130, and the controller 130 makes the difference between the saturation temperature corresponding to the discharge pressure of the compressor 22 and the suction temperature of the CO ₂ refrigerant to the compressor 22 constant. The opening amounts of the expansion valves 106a and 106b are adjusted so that the CO ₂ refrigerant supply amount to the plate heat exchangers 32a and 32b is adjusted. Moreover, the opening degree of the electromagnetic valves 108 and 110 is adjusted as necessary.

Next, the whole structure of the hot air generator 10 which concerns on a present Example is demonstrated using FIG.2 and FIG.3. FIG. 2 is a side view of the hot air generator according to the present embodiment, and FIG. 3 is a schematic plan view of the hot air generator according to the present embodiment. However, in FIG. 3, description of a gas cooler and piping is abbreviate | omitted.
The hot air generator 10 is provided with a substrate 14 that forms the bottom surface and has a flat surface. A space 12 is located above the substrate 14, and a compressor 22 and plate heat exchangers 32 a and 32 b are disposed on the substrate 14 in the space 12. The compressor 22 is disposed on the right side of the space 12 (the right side in FIG. 2 and the lower side in FIG. 3), and the plate heat exchangers 32a and 32b are on the left side facing the right side. (The left side in FIG. 2 and the upper side in FIG. 3), and the compressor 22 and the plate heat exchangers 32 a and 32 b can be drawn out of the space 12 from the side surfaces on the arranged side. It is configured. By arranging the compressor 22 and the plate heat exchangers 32a and 32b in this manner, the compressor 22 is pulled out from the right side surface of the space 12 to the outside of the space 12 during the maintenance and inspection work. The exchangers 32a and 32b can be pulled out of the space 12 from the left side. Accordingly, since the device can be pulled out of the space using the two surfaces, the maintenance and inspection work can be facilitated and the space required for the maintenance and inspection work can be saved.

  The space 12 including the compressor 22 and the plate heat exchangers 32 a and 32 b is surrounded by the gantry 16. The gantry 16 needs to have a size and a shape that can surround the compressor 22 and the plate heat exchangers 32a and 32b, and a strength that allows the gas cooler 24 to be placed thereon.

  The supercritical tanks 26 a and 26 b are provided outside the gantry 16 surrounding the space 12. In the present embodiment, the supercritical tanks 26a and 26b are provided outside the gantry 16, but the cradle 16 does not interfere with the drawing of the compressor 22 and the plate heat exchangers 32a and 32b out of the space 12. If it does not become extremely large, it may be provided in the gantry 16.

  Further, a gas cooler 24 is placed and fixed on the gantry 16. Space can be saved by mounting and fixing the gas cooler 24 on the mount 16.

Next, the configuration of the gas cooler 24 will be described with reference to FIG. FIG. 4 is a perspective view of the gas cooler 24.
The gas cooler 24 is a plate fin tube type gas cooler including a plurality of tubes 48 and a plurality of fins 46 through which the tubes 48 pass.
The plurality of tubes 48 form a plurality of rows (36 rows in this embodiment) by arranging a plurality of tubes along the direction in which air passes, and a plurality of tubes (this embodiment) in the vertical direction in each of the plurality of rows. In the example, although not shown in the drawing, 45 stages) are arranged in a plurality of stages. An inlet header 42 and an outlet header 44 are provided vertically at the inlet and outlet of the gas cooler 24, respectively. The inlet header 42 is connected to the discharge side of the compressor 22, and the outlet header 44 is connected to a line that branches into the branch passages 102, 100a, and 100b as shown in FIG.

  The plurality of fins 46 are composed of a plurality of divided fins that are divided along the direction in which air flows, and in this embodiment, the number of rows of tubes that penetrates in order from the upstream of the air flow is five. It is composed of 11 divided fins which are 5 rows, 5 rows, 5 rows, 5 rows, 5 rows, 2 rows, 1 row, 1 row, 1 row, 1 row.

In the gas cooler 24 configured as described above, when hot air is generated, the air side causes air as a medium to be heated to flow between the plurality of fins 46. On the other hand, the refrigerant side supplies the supercritical CO ₂ refrigerant supplied from the discharge of the compressor 22 into the inlet header 42. The supercritical CO ₂ refrigerant supplied to the inlet header 42 is distributed and supplied to the tubes 48 a, 48 b, 48 c... And exchanges heat with the air flowing between the plurality of fins 46 to generate hot air. 44 is discharged. The CO ₂ refrigerant discharged to the outlet header 44 is supplied to downstream equipment according to the flow sheet shown in FIG.

Incidentally, the tube 48a passes through the plurality of fins 46 in the air flow direction downstream of the column, through the folding passage 49a, is connected to 48a ₂ penetrating the fins 46 in the second column from the air flow direction downstream The As described above, by repeatedly connecting the return passages 49a, 49a ₂ ... And the tubes 48a, 48a ₂ ..., The CO ₂ refrigerant introduced into the tubes 48a passes through the plurality of fins 46 in all 36 rows. It passes through the tube and is discharged to the outlet header 44. The same applies to the tubes 48b, 48c.

In the gas cooler 24, as it goes downstream of the air flow, the temperature of the refrigerant flowing through the air and the tube is higher, and the temperature of the air becomes closer to the target hot air temperature. By constituting the fin 46 from a plurality of divided fins, heat transfer between the divided fins can be prevented even within the same fin. Therefore, as the air flows downstream, the number of tubes passing through the divided fins is reduced, that is, the width of the divided fins in the air flow direction is reduced so that the air temperature is close to the target hot air temperature. The hot air temperature can be stabilized.
Furthermore, the higher the temperature of the refrigerant flowing through the air and the tube, the larger the thermal expansion of the divided fins, but the smaller the width of the divided fins in the larger thermal expansion region, the influence of deformation due to thermal expansion, The influence of thermal distortion can be kept small.

Further, the gantry 16 is provided, and the gas cooler 24 is installed above the compressor 22 as the upstream device and the plate heat exchangers 32a and 32b as the downstream devices, and the inlet header 42 and the outlet header 44 are vertically arranged. Provided. Therefore, even when refrigeration oil such as compressor lubricating oil is mixed in the CO ₂ refrigerant, the refrigeration oil does not accumulate in the tube forming the gas cooler and easily falls downward due to gravity. Therefore, the refrigerating machine oil mixed in the refrigerant can be dropped downward by gravity, circulated through the refrigerant circulation path together with the refrigerant, and recovered to the compressor.

Further, if the piping through which the CO ₂ refrigerant circulates, particularly the tube constituting the gas cooler 24, is made of stainless steel, the thickness of the piping can be reduced, and the overall weight of the apparatus can be reduced.

  A hot air generator that generates hot air by passing air through a gas cooler that constitutes a heat pump cycle. Space saving is possible, and refrigeration oil such as lubricating oil of a compressor that constitutes the heat pump cycle is used as a refrigerant circulation path. Even if it is mixed in, it can be easily recovered, and further, it can be used as a hot-air generator that can safely and easily perform maintenance and inspection work of component equipment.

DESCRIPTION OF SYMBOLS 10 Hot-air generator 12 Space 14 Substrate 16 Base 22 Compressor 24 Gas cooler 25a, 25b Duct 26a, 26b Refrigerant tank 32a, 32b Plate type heat exchanger (water heat source evaporator)
36 Heat source water supply pipe 38 Heat source drain pipe 42 Inlet header 44 Outlet header 46 Fin 48 Tube 108, 110 Solenoid valve 112 Temperature sensor 128 Pressure sensor 130 Controller

Claims (5)

A compressor, a gas cooler, an expansion valve, and a water heat source evaporator are connected in series on the refrigerant circulation path to form a heat pump cycle that circulates the refrigerant through these devices, and air is passed through the gas cooler to generate heat from the refrigerant. A hot air generator that generates hot air by raising the temperature by replacement,
Providing a frame surrounding a space including the compressor and the water heat source evaporator, and disposing the gas cooler on the frame;
The gas cooler includes a plurality of fins arranged in parallel and an inlet header and an outlet header provided on an inlet side and an outlet side of the plurality of fins, and the inlet header and the outlet header are arranged vertically. A featured hot air generator. The gas cooler is a plate fin tube type gas cooler including a plurality of fins through which the plurality of tubes pass,
The plurality of tubes are arranged in a plurality of rows along the direction in which the air is ventilated to form a plurality of rows, and in each of the plurality of rows, a plurality of tubes are arranged in a vertical direction to form a plurality of stages,
Each of the plurality of fins is composed of a plurality of divided fins divided along the direction in which the air passes.
The tube of the said division | segmentation fin more than the division | segmentation fin located in the air flow downstream along the direction which the said air ventilates rather than the said division | segmentation fin has penetrated. Hot air generator.   The compressor is arranged near one side surface of the space surrounded by the gantry and can be pulled out of the space, and the water heat source evaporator is arranged near the side surface opposite to the one side surface. The hot air generator according to claim 1, wherein the hot air generator can be pulled out.   The hot air generator according to claim 1, wherein the water heat source evaporator is composed of a plurality of plate heat exchangers arranged in parallel. The hot air generator according to claim 1, wherein the refrigerant is CO ₂ and constitutes a heat pump cycle in which CO ₂ is in a supercritical state on the outlet side of the compressor.

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