JP2011247499A - Air heat exchanger and refrigeration cycle apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problems in a refrigeration cycle apparatus equipped with an air heat exchanger that when defrosting operation is carried out, frost does not completely melt on a surface of fins of the air heat exchanger subjected to water-repellent surface treatment, but drops off in a form of ice droplets into an upstream side of an air flow in the air heat exchanger and accumulates to form a barrier wall of an ice block, and the barrier wall of the ice block reduces an inflow air amount to the air heat exchanger and causes reduction in the performance of the refrigeration cycle apparatus or failure in an outdoor unit of a heat source unit.SOLUTION: In the air heat exchanger having a plurality rows of fins arranged in an air flow direction, the surfaces of air-upstream-side fins of the air heat exchanger are hydrophilized, while surfaces of air-downstream-side fins of the air heat exchanger are made water-repellent.

Description

  Embodiments described herein relate generally to an air heat exchanger and a refrigeration cycle apparatus.

For example, refrigeration cycle apparatuses such as an air conditioner and a heat pump water heater are provided with a heat exchanger for heating or storing hot water in the room and an air heat exchanger for exchanging heat with outdoor air.
During heating operation in an air conditioner or hot water storage operation in a heat pump water heater, if the outside air temperature is low, frost is generated on the fin surface of the outdoor air heat exchanger, and the air flow path between adjacent fins of the air heat exchanger To narrow. Thereby, the heat exchange efficiency of an air heat exchanger falls.

  On the other hand, as in Patent Document 1, water-repellent surface treatment is applied to the windward fin surface in the air circulation direction of the air heat exchanger to suppress frost formation and delay the freezing of the air heat exchanger. It has been known.

JP-A-63-3182

  However, when heating operation is performed for a long time at a low temperature, frost grows on the fin surface of the air heat exchanger that has been subjected to the water-repellent surface treatment, and drop-shaped ice blocks are generated. It is necessary to perform a defrosting operation appropriately to melt the frost (ice block).

Therefore, when the defrosting operation is performed in the refrigeration cycle apparatus including the air heat exchanger of Patent Document 1 described above, the frost is not completely melted in the fins of the air heat exchanger subjected to the water-repellent surface treatment. Then, it becomes a drop-shaped ice mass and falls to the windward side of the air heat exchanger. The dropped ice blocks are stacked to form an ice block barrier.
This ice block barrier reduces the amount of air flowing into the air heat exchanger, resulting in a malfunction that causes performance degradation and failure of the refrigeration cycle apparatus.

  In order to solve the above-mentioned problems, according to an embodiment of the present invention, a cross fin tube type air heat exchanger comprising a fin row composed of a plurality of plate fins and a heat transfer tube provided through the fin row. The fin rows are arranged in a plurality of rows in the air flow direction, the fin surface of the fin row on the windward side in the air flow direction is hydrophilic, and the fin surface of the fin row on the leeward side is water repellent. Or a cross fin tube type air heat exchanger comprising a fin row composed of a plurality of plate fins and a heat transfer tube provided through the fin row. Fins arranged in at least three rows in the flow direction, wherein the fin surface of the fin row on the most windward side and the most leeward side in the air flow direction is hydrophilic and located between the two The fin surface air heat exchanger, characterized in that a water-repellent, is provided in the refrigeration cycle apparatus.

1 is a schematic diagram of a refrigeration cycle apparatus according to an embodiment of the present invention. The perspective view of the air heat exchanger which concerns on 1st Embodiment. The figure which shows the frost formation state of the air heat exchanger with which the hydrophilic surface treatment was performed. The figure which shows the frost formation state of the air heat exchanger with which the water-repellent surface treatment was performed. The figure which inclined the air heat exchanger which concerns on 1st Embodiment in the air upstream direction. The perspective view of the air heat exchanger which concerns on 2nd Embodiment.

  An embodiment of the present invention will be described with reference to FIGS.

(First embodiment)
The configuration of the refrigeration cycle apparatus 1 according to the first embodiment will be described with reference to FIG.
The refrigeration cycle apparatus 1 is used, for example, in an air conditioner or a heat pump water heater, and the configuration thereof includes a compressor 2, a four-way valve 3, an air heat exchanger 4 that is an outdoor heat exchanger, an expansion valve 5, and an indoor heat exchange. The vessel 6 is sequentially connected by a refrigerant pipe 20.
A blower 25 for exchanging heat with the outside air is provided in the vicinity of the air heat exchanger 4.

  The heating operation of the air conditioner or the hot water storage operation of the heat pump water heater is performed as follows.

  When the compressor 2 is driven to compress and discharge the refrigerant to a high temperature and high pressure, the refrigerant is led from the four-way valve 3 to the indoor heat exchanger 6 to condense as shown by the solid line arrow in FIG. To do. This condensation heat becomes a heat source for heating the room or boiling hot water.

  The refrigerant expands under reduced pressure at the expansion valve 5 and is sent into the air heat exchanger 4. At this time, heat is absorbed from the outside air blown by driving the blower 25, and the refrigerant in the air heat exchanger 4 evaporates.

  Further, the refrigerant is sucked into the compressor 1 from the air heat exchanger 4 through the four-way valve 3, is compressed, and circulates again in the above-described path.

  If the above-described heating operation or hot water storage operation is performed for a long time in a state where the outside air temperature is low, frost (ice block) may adhere to the surface of the air heat exchanger 4 and the air heat exchanger 4 may freeze. In such a case, a defrosting operation for removing frost is performed.

  This defrosting operation is performed by switching the four-way valve 2 so that the refrigerant circulates along a path indicated by a broken-line arrow in FIG.

  Specifically, when the compressor 2 is driven and the refrigerant is compressed and discharged at a high temperature and a high pressure, the refrigerant is led from the four-way valve 3 to the air heat exchanger 4 to condense and condense, as indicated by broken line arrows in FIG. Release heat. This condensation heat becomes a heat source for melting frost.

Thereafter, the refrigerant expands under reduced pressure in the expansion valve 5 and evaporates in the indoor heat exchanger 6.
Subsequently, the refrigerant is sucked into the compressor 1 from the indoor heat exchanger 6 through the four-way valve 3, is compressed, and circulates again in the above-described path.

The configuration of the air heat exchanger 4 will be described with reference to FIG.
The air heat exchanger 4 is a cross fin tube type heat exchanger, and includes a large number of plate fins 10 forming a heat exchange surface and a heat transfer tube 11 through which a refrigerant flows.
The plate fins 10 are arranged such that the longitudinal direction thereof is the vertical direction, and a large number of plate fins 10 are arranged in parallel in the direction perpendicular to the air flow direction indicated by the arrows to form a fin row 12.
A heat transfer tube 11 is provided penetrating the plate fin 10 of the fin row 12.

  A plurality of heat transfer tubes 11 are arranged at equal intervals along the longitudinal direction of the plate fin 10.

  The fin rows 12 are provided in two rows in the air flow direction. The fin row 12 including the windward heat transfer tubes 11 is used as the windward air heat exchange element 4a, and the fin row 12 including the leeward heat transfer tubes is leeward. Let it be the side air heat exchange element 4b.

  Here, the surface of the plate fin 10 of the windward air heat exchange element 4a is subjected to hydrophilic surface treatment, and the surface of the plate fin 10 of the leeward air heat exchange element 4b is subjected to water repellent surface treatment. .

  Below the air heat exchanger 4, a drain pan 26 that receives water droplets and ice blocks flowing down from the air heat exchanger 4 is provided.

  According to the first embodiment described above, frost (ice block) can be removed during the defrosting operation performed after frost formation.

  When the air heat exchanger 4 is frosted, the windward air heat exchange element 4a is subjected to hydrophilic surface treatment on the surface of the plate fin 10, so that the entire plate fin 10 is film-like as shown in FIG. Frost (ice block) 15a is formed. On the other hand, since the leeward air heat exchange element 4b has a water-repellent surface treatment applied to the plate fin 10, a drop-like frost (ice block) 15b is formed on the surface of the plate fin 10 as shown in FIG.

  In this state, when the defrosting operation of the refrigeration cycle apparatus 1 is performed, since the surface of the plate fin 10 of the upwind air heat exchange element 4a is hydrophilic, the boundary portion of the frost in contact with the plate fin 10 is melted. Even if the ice block does not fall off, it stays on the surface of the plate fin 10, completely melts to become drain water, and flows down to the drain pan 26 provided at the lower part of the air heat exchanger 4.

  On the other hand, since the surface of the plate fin 10 of the leeward side air heat exchange element 4b is water-repellent, the boundary portion of the frost in contact with the plate fin 10 during the defrosting operation melts, and the ice block completely melts. It falls to the drain pan 26 below the air heat exchanger 4 before.

At this time, the ice block falls on the windward side and the leeward side of the fin row 11 while colliding with the heat transfer tube 11. The ice blocks to be dropped to the windward side are attached to the hydrophilic plate fin 10 surface of the windward air heat exchange element 4a, and are all melted and drained without falling to the windward side from the windward air heat exchange element 4a. It flows down to the drain pan 26 and is discharged outside the outdoor unit.
Further, by driving the blower 25 during the defrosting operation, the ice blocks that have fallen to the leeward side from the leeward side air heat exchange element 4b are melted by the heat of the airflow that has taken away the heat of condensation.

  Further, as shown in FIG. 5, the fin row 12 of the air heat exchanger 4 is provided so as to be inclined so that the upper end portion in the longitudinal direction of the plate fin is located on the windward side in the air inflow direction from the lower end portion. It may be arranged. By arranging in this way, the ice mass does not fall or scatter in the downstream direction of the leeward air heat exchange element 4b, but falls in the upstream direction and adheres to the surface of the plate fin 10 of the windward air heat exchange element 4a. The adhering ice mass is completely melted, becomes drain water, flows down to the drain pan 26, and is discharged outside the outdoor unit.

  By setting the air heat exchanger 4 to the above-described configuration, it is possible to remove all the ice blocks that hinder the air flow in the air heat exchanger 4 and to suppress a decrease in heat exchange efficiency.

(Second Embodiment)
The second embodiment will be described below. In addition, about the part same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. The configuration of the refrigeration cycle apparatus 1 is the same as that shown in FIG.
As a configuration different from the first embodiment, as shown in FIG. 6, the air heat exchanger 14 of the second embodiment has three rows of fin rows 12 arranged in parallel in the air circulation direction, The leeward air heat exchange element 14a, which is the fin row 12, the leeward air heat exchange element 14c, which is the most leeward fin row 12, and the intermediate air heat exchange element 14b, which is the fin row 12 positioned between the two. It consists of

  The surfaces of the plate fins 10 of the windward side air heat exchange element 14a and the leeward side air heat exchange element 14c are subjected to hydrophilic surface treatment, and the surface of the plate fins 10 of the intermediate air heat exchange element 14b is water repellent. Surface treatment is applied.

  By setting it as the above-mentioned structure, at the time of the defrost operation performed after frost formation, an ice block does not fall to the windward side of the windward air heat exchange element 14a like 1st Embodiment.

  Further, the ice mass falling or scattering to the leeward side of the intermediate air heat exchange element 14b contacts and adheres to the surface of the plate fin 10 subjected to the hydrophilic surface treatment of the leeward air heat exchange element 14c. As a result, it is possible to suppress the falling and scattering of ice blocks to the leeward side of the air heat exchanger 14, all of which is melted by the heat of the air heat exchanger 14 that is a condenser, flows down to the drain pan 26, and is discharged outside the outdoor unit. Is done.

  Here, three or more fin rows 12 may be arranged in parallel, and a plurality of rows of intermediate air heat exchange elements 14b may be provided.

  According to the embodiment described above, failure of the refrigeration cycle apparatus can be prevented without reducing the heat exchange efficiency of the air heat exchanger in the operation of the refrigeration cycle apparatus in a state where the outside air temperature is low.

1 ... Refrigeration cycle device, 2 ... Compressor, 3 ... Four-way valve, 4 ... Air heat exchanger, 4a ... Upstream heat exchange element, 4b ... Downstream heat exchange element, 5 ... Expansion valve, 6 ... Indoor heat exchange 10 ... plate fins, 11 ... heat transfer tubes, 12 ... fin rows, 14 ... air heat exchangers, 14a ... upstream heat exchange elements, 14b ... intermediate heat exchange elements, 14c ... leeward heat exchange elements, 15 ... frost (Ice block), 15a ... frost (ice block), 15b ... frost (ice block), 20 ... refrigerant piping, 25 ... blower, 26 ... drain pan

Claims (4)

  In a cross fin tube type air heat exchanger comprising a fin row composed of a plurality of plate fins and a heat transfer tube provided penetrating through the fin row, the fin rows are arranged in a plurality of rows in the air flow direction, An air heat exchanger characterized in that the fin surface of the fin array on the leeward side in the air circulation direction is hydrophilic and the fin surface of the fin array on the leeward side is water repellent.   In a cross fin tube type air heat exchanger comprising a fin row composed of a plurality of plate fins and a heat transfer tube provided penetrating the fin row, at least three or more rows of the fin rows are arranged in the air flow direction. The fin surface of the fin row on the most windward side and the most leeward side in the air circulation direction is hydrophilic, and the fin surface of at least one fin row located between the two is water repellent. Air heat exchanger.   3. The air heat according to claim 1, wherein each fin row is provided so as to be inclined so that an upper end portion in a longitudinal direction of the plate fin is located on an upwind side in an air flow direction with respect to a lower end portion. Exchanger.   A refrigeration cycle apparatus comprising the air heat exchanger according to any one of claims 1 to 3.

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