JP2016023925A - Evaporation air conditioning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved evaporation condenser and an improved evaporation cooling method for an air conditioning system.SOLUTION: This invention relates to an evaporation condenser 1 for a separate type air conditioning unit. There are arranged a plurality of tubes 2 enabling refrigerant to flow. There are provided tubes having upright fins arranged along upper segments of the tubes, a water supply system for distributing water onto the tubes and the fins, and a fan 10 for producing an air stream to flow on the tubes and the fins for evaporating water attached to the tubes and the fins. The tubes also have upright fins arranged along tube bottom parts. The upper fins extend from the upper part of the tube in an upward direction and the bottom fins extend from the tube bottom part in a downward direction. All the composing elements described above are packaged in an outdoor unit for a separate type air conditioning unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an air conditioning system. More particularly, the present invention relates to an improved evaporation type air conditioning system and method.

  The split type air conditioner includes air-cooled fins and a tube condenser disposed in an outdoor unit. The outdoor unit is separated from the indoor unit that houses the evaporator. During the air conditioning process, the vapor refrigerant is pumped from the compressor into the condenser to change the vapor into a liquid. This liquid is then circulated to an expansion device that reduces the pressure and temperature of the refrigerant, such as a capillary tube or expansion valve. The refrigerant flows into the evaporator in the indoor unit and cools the space adjusted indoors.

  According to the present invention, a water cooled condenser or evaporative condenser is provided to improve the heat exchange process of a split type air conditioning system. Outdoor evaporative condensers may require a separate cooling tower to cool the water and remove heat into the atmosphere. Usually, the cooling tower is installed outdoors and corresponds to a large heat load.

  The evaporative air conditioner usually has a water supply device for supplying water to the condenser and a fan for sending ambient air onto the condenser. Air evaporates the water film on the surface of the condenser, thus removing heat from the refrigerant in the condenser by evaporative cooling.

  For example, water from the top is dripped or sprayed onto the condenser tube, and the fan is operable to draw an air stream and flow upward on the tube, thereby causing the water flow direction To evaporate the water. The latent heat of vaporization is absorbed when the water evaporates into steam and is carried into an air stream that discharges the steam and heat into the atmosphere. Due to the high specific heat and latent heat of water vaporization, the evaporative condenser is more effective at removing heat than conventional air-cooled condensers. This reduces the condensing pressure of the air conditioning system, thereby improving energy efficiency.

  Some prior art documents disclose the use of evaporative condensers in air conditioning systems. For example, water in an evaporative cooler can be collected by gravity or spraying on tortuous tubes as disclosed in US Pat. No. 2,166,397 and US Pat. No. 4,683,101 and US Pat. No. 4,626,387 and US Distributed on helical coils as disclosed in US Pat. No. 5,046,331 and on fin and tube coils as disclosed in US Pat. No. 2,278,242. U.S. Pat. No. 6,766,655 discloses a streamlined tube having a front head portion and a rear tail portion, wherein a plurality of streamline tubes are two at two opposite ends of the tube. Fixed on one support plate. The evaporative condenser disclosed in the document is configured as a cooling tower different from the present invention.

  The present invention provides an improved evaporative condenser and evaporative cooling method for a split type air conditioning system. The evaporative condenser comprises a plurality of tubes, which reduce the shape drag resulting from the flow of air over the tubes of the condenser and thus wake splitter fins to reduce the pressure drop on the air side Have As an air stream or flow flows over the tube, a recirculation vortex is created downstream at the rear end of the tube. Splitter fins separate vortices or wakes generated from both sides of the tube, thus preventing them from interacting. Evaporative cooling according to the present invention is achieved by evaporation of a water film from the surface of the tube and its splitter fin.

  According to the present invention, the evaporation condenser for the split type air conditioning unit is a plurality of tubes for allowing the refrigerant to flow, and has upright fins disposed along the upper portion of the tubes. A tube, a water supply system for distributing water over the tubes and fins, and a fan for creating a stream of air to flow over the tubes and fins to evaporate the water attached to the tubes and fins . The tube further comprises upstanding fins disposed along the bottom of the tube. The top fin extends upward from the top of the tube and the bottom fin extends downward from the bottom of the tube. The fins can be attached to the tube. The tubes are placed next to each other, where the fins are parallel to the corresponding fins in the upright position. The tubes are arranged with the fins of the top tube aligned with the fins of the bottom tube in an alternating arrangement. This arrangement forms a tube bank that acts as a filling medium. The fins have upstanding sidewalls, where the sidewalls include forms with non-uniform surfaces, such as grooves and indentations, to increase the surface area and disrupt the formation of a water film on the surface area. The air stream drawn by the fan is forced to flow over the curved surface of the tube and the upstanding side walls of the fin. The evaporative condenser is also a piping system located between the water supply system and the tube bank to allow the refrigerant superheated gas to be cooled by the water before entering the tube bank and being further cooled. Is provided. All the above components are packaged in an outdoor unit for a split type air conditioning unit.

  Referring to FIG. 1, an example of refrigerant circulation in an evaporative cooling system of a split type air conditioner is shown. The evaporative cooling system includes an evaporative condenser (1) in communication with the evaporator via a piping system. As shown in FIG. 1, the evaporative condenser (1) is connected to the evaporator (9) via a first copper pipe (6, 8) and a second copper pipe (6, 8). The first copper pipe is connected between them through the expansion valve (5) and the first stop valve (7). The second copper pipe is connected through the compressor (4) and the second stop valve (7). The condenser (1), the compressor (4), the expansion valve (5), and the associated piping system form a split type air conditioner outdoor unit separated from the indoor evaporator unit (9). The evaporative condenser (1) is a plurality of tubes (2) for allowing refrigerant to flow, each having upright fins disposed along the top and bottom of the tube (2). Provide a tube. The evaporative condenser further comprises a water supply system for distributing water over the tubes and their fins. A spray nozzle (14) is provided at the top of the condenser to spray water onto the tube and its fins. A water tray with dispensing holes can also be provided to allow water to drip onto the tube and its fins. Water attaches to the tube and its fins in the form of a water film. A fan is provided to create a stream of air to flow over the tubes and fins to evaporate water attached to the tubes and their fins into steam. A reservoir pan (12) is provided at the bottom of the reservoir to collect any water droplets, where the water is then recirculated back by the pump (13) and redistributed onto the tube and its fins. The high latent heat of vaporization of water from the wet surface of the tube and its fins results in a high heat transfer coefficient compared to the dry surface. This improves the efficiency of the condensation process and the overall refrigerant cycle of the air conditioner.

  As shown in FIG. 2, the tube has a top upstanding fin (16a) and a bottom upstanding fin (16b). The fins are aligned 180 degrees away from each other and parallel to the flow direction of the air stream (163). The tubes are arranged next to each other in a staggered arrangement, where the fins are parallel to the corresponding fins in the upright position. As shown in FIG. 3, the fin separates the recirculation vortex (17) generated on both sides downstream of the tube, thus preventing vortex interaction and vortex formation. This reduces pressure drop and improves pressure recovery.

  The invention will be further described by way of example with reference to the accompanying drawings.

It is a figure which shows the refrigerant | coolant circulation of the evaporative cooling system for division | segmentation type air conditioners. FIG. 6 shows a condenser tube with wake splitter fins. FIG. 6 shows an air velocity profile on a tube with wake splitter fins. It is a figure which shows the structure of the wake splitter fin on a tube. It is a figure which shows the structure of the wake splitter fin on a tube. It is a figure which shows another structure of the wake splitter fin on a tube. It is a figure which shows another structure of the wake splitter fin on a tube. FIG. 6 shows geometry of wake splitter fins on a tube. It is a figure which shows the header cover for tube banks. It is a figure which shows the refrigerant | coolant circulation of the evaporative cooling system provided with the overheating prevention loop for division | segmentation type air conditioners. FIG. 3 shows a method for generating an air stream for flowing over a tube bank. FIG. 3 shows a method for generating an air stream for flowing over a tube bank. FIG. 6 illustrates another method for generating an air stream for flow over a tube bank. It is a figure which shows another arrangement | positioning of a tube. It is a figure which shows another arrangement | positioning of a tube.

  As shown in FIG. 4a, a wake splitter fin (18) may be attached to the tube. The tubes are placed next to each other so that the fins are parallel and aligned with each other in the upright position. The top fin extends upward or upstream from the top of the tube, and the bottom fin extends downward from the bottom of the tube in the upright position or downstream of the tube to form a unitary structure. Form. This configuration is suitable for tubes and flow splitters made from metal. In FIG. 4b, the wake splitter fin (19) is not attached to the tube. Top and bottom fins are proximal to the tube. The tubes are placed next to each other so that the fins are parallel and aligned with each other in the upright position. In FIGS. 5a and 5b, only the upper wake splitter fin is disposed at the top of the tube. FIG. 5a shows the upper wake splitter fin (20a) attached to the tube into a unitary structure, and FIG. 5b shows the upper flow splitter fin (20b) not attached to the tube.

  Referring to FIG. 6, the geometry of the tube bank has six parameters: a) tube longitudinal pitch SL, b) tube transverse pitch, St, c) splitter fin length, L, d) tube diameter D, e) tube wall thickness, tw, and f) fin thickness ft. The diameter of the tube is determined by the operating pressure of the fluid in the tube, for example the refrigerant. Smaller tube diameters and thicker wall thicknesses are required for higher working pressures, and vice versa. The diameter and number of tubes in the bank determines the amount of heat required for the heat exchanger.

  The L / D ratio can range between 0.50 and 1.50, with a ratio of 1.00 being preferred. The range of the longitudinal pitch is given as SL> L + D / 2, while the transverse pitch is given as D / 2 <St <D. The fin thickness should be as thin as possible.

  The staggered arrangement of tubes with the mentioned transverse pitch allows waterfall water from the upper tube to flow to the top and sides of the bottom tube, which then repeats the cascade effect and external Ensure good wetting of the tube surface.

  The integral flow splitter tube can be made of metal. However, it is also possible to make tubes and flow splitters with polymer materials that are thermally reinforced or not reinforced, or with any metal / polymer combination in view of the high heat transfer coefficient of the evaporating water film on the outer tube surface It is.

  In order to enhance the heat transfer performance of the evaporative heat exchanger, the inner surface of the tube can have a spiral groove pattern to promote boundary layer disturbances that improve the internal heat transfer coefficient. Similarly, the outer surface of the wake splitter fin has a geometry modification such as a lateral groove (21) to induce disturbances in the water and air film layers flowing over the surface of the tube and fin, Can help increase the external heat transfer coefficient. An example of a lateral groove is shown in FIG.

  When air flows over the water film and absorbs the latent heat of vaporization, condensation of the refrigerant flowing in the tube occurs. The refrigerant changes from the vapor phase to the liquid phase in the tube.

As shown in FIG. 7, the refrigerant flows through the tube bank via a header cover (22) attached to the side of the condenser. The refrigerant enters the condenser via the inlet (23) of the first header cover and leaves the outlet (24) of the second header cover. Individual end plates (25) are disposed at both ends of the condenser to hold the tubes in place. A copper tube (6) is connected to the inlet and outlet. The tubes can be connected by screw fitting or welding. The connection can take the form of the following configuration.
a) Refrigerant hot superheated gas from the compressor is led to the inlet (23) where it is liquefied and then exits the evaporative condenser as cooled liquid refrigerant through the outlet (24). This connection is shown in FIG.
b) Refrigerant hot superheated gas from the T compressor is directed to the overheat prevention loop (26) before entering the inlet (23). The loop is placed below the water spray (14) or water distributor (15), where the refrigerant is cooled by water and then led to the inlet (23) of the evaporative condenser (23) and the outlet (24 ) Exits as a cooled liquid refrigerant. This connection is shown in FIG.

  The fan (10) is used as a means for generating an air stream so that this air stream can flow over the tube bank. The air stream can flow in a flow direction that opposes the flow of water. When the fan is placed at the top of the tube bank, air is drawn out to flow upward, opposite the water flowing from the top. The fans are arranged on the sides (27a, 27b) of the tube bank as shown in FIG. 9 to allow air to flow laterally perpendicular to the fins. In FIG. 10, air (18) flows in parallel along the tube. In FIG. 11, the tubes are arranged such that the fins are positioned in a horizontal position where air flows perpendicular to the fins. The flow of water from the top tube flows in a waterfall towards the bottom tube, moistening the upper surface (29a) and leaving the lower surface (29b) unwet.

Claims (16)

An evaporative condenser for a split type air conditioning unit,
A plurality of tubes forming a tube bank for allowing refrigerant to flow, wherein the individual tubes have upstanding fins disposed along the top of the tubes;
A water supply system for distributing water over the fins and the tubes;
An evaporative condenser for a split type air conditioning unit, comprising a fan for creating an air stream for flowing over the tube and the fin to evaporate the water attached to the tube and the fin.   The evaporative condenser for a split-type air conditioning unit according to claim 1, further comprising upright fins arranged along the bottom of the tube.   The evaporative condenser for a split type air conditioning unit according to claim 1, wherein the fin extends upward from an upper portion of the tube.   The evaporative condenser for a split type air conditioning unit according to claim 2, wherein the fin extends downward from a bottom of the tube.   The evaporative condenser for a split type air conditioning unit according to claim 1 or 2, wherein the fin is attached to the tube.   The evaporative condenser for a split-type air conditioning unit according to claim 1 or 2, wherein the tubes are arranged next to each other and the fins are parallel to each other in an upright position.   The evaporative condenser for a split-type air conditioning unit according to claim 1, wherein the tubes are arranged such that the fins of the upper tube are aligned with the fins of the bottom tube in a staggered arrangement.   The evaporative condenser for a split-type air conditioning unit according to claim 1 or 2, wherein the fins have side walls with non-uniform surfaces such as lateral grooves and indentations to increase the surface area.   The evaporative condenser for a split-type air conditioning unit according to claim 8, wherein the air stream is forced to flow over the curved surface of the tube and the surface of the sidewall of the fin to prevent shape drag.   2. The split type air conditioning unit according to claim 1, wherein the water supply system includes a spray nozzle disposed at an upper portion of the tube bank and a pump for recirculating water dropped on the reservoir pan. Evaporative condenser.   The split according to claim 1, wherein the water supply system includes a tray with a distribution hole disposed at the top of the tube bank and a pump for recirculating water dripped onto the reservoir pan. Evaporation condenser for type air conditioning unit.   Furthermore, a piping loop located between the water supply system and the tube bank to allow the superheated gas of the refrigerant to be cooled by the water before entering the tube bank and further cooled The evaporative condenser for a split type air conditioning unit according to claim 1, comprising:   The evaporative condenser for a split type air conditioning unit according to claim 1, wherein the fan is located at an upper portion of the tube bank and draws air to flow upward.   The evaporative condenser for a split type air conditioning unit according to claim 1, wherein the fan is disposed on a side portion of the tube bank and pushes air to flow sideways.   The evaporative condenser for a split-type air conditioning unit according to claim 1, packaged in an outdoor unit and in communication with an indoor evaporator unit.   13. The evaporative condenser for a split type air conditioning unit according to claim 12, packaged in an outdoor unit and in communication with the indoor evaporator unit.

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