JPH0354384Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a refrigeration system that has an air curtain at the opening for entering and exiting products, and in particular, the invention relates to a refrigeration system that has an air curtain at the opening for entering and exiting products. Regarding defrosting.

(Prior art and its problems) In a refrigeration system that has an air curtain consisting of a cold air flow at the opening for loading and unloading products, the following is proposed to prevent the temperature inside the refrigerator from rising during defrosting. has been done. In other words, it is a refrigeration system equipped with a compressor, a condenser, two evaporators arranged in one case ventilation passage, and other expansion valves, etc. During normal operation, the expansion from the compressor and condenser is After passing through the valve, a path is formed for the refrigerant to pass through two evaporators in parallel and return to the compressor. At this time, the high-pressure hot gas compressed by the compressor radiates heat and liquefies in the condenser, and this liquid refrigerant is throttled and expanded in the expansion valve and vaporizes in the evaporator by taking away the heat of the circulating air. In this way, the two evaporators provide powerful cooling of the circulating air. On the other hand, when defrosting either one of the evaporators, a refrigerant path is formed that bypasses the condenser from the compressor, goes directly to one of the evaporators, and then returns to the compressor via the expansion valve and the other evaporator. . At this time, the high-pressure hot gas compressed by the compressor is liquefied by dissipating heat in one of the evaporators, that is, this evaporator acts as a condenser, and defrosting is performed by the heat dissipated at that time.
The liquid refrigerant thus obtained is throttled and expanded by the expansion valve and vaporized by absorbing the heat of the circulating air in the other evaporator. In this way, one evaporator is defrosted while the other evaporator cools the circulating air.

However, in such a refrigeration system, during normal operation, the refrigerant path is formed so that the two evaporators are connected in parallel, but during defrosting, the evaporators are connected in series while bypassing the condenser. Since it is necessary to form a refrigerant path in this way, there is a problem in that the piping structure that constitutes the refrigerant path becomes complicated.

(Purpose of the invention) This invention was made in view of the above problems, and the purpose is to provide a refrigeration system that has a simple piping structure and can effectively prevent the temperature inside the refrigerator from rising during defrosting. do.

(Means for Achieving the Object) This invention is a refrigeration system having an air curtain at the opening. A heat exchanger and an evaporator are arranged in series, and a compressor, a condenser, and a pressure reducer are provided for the heat exchanger and the evaporator, and during normal operation, the compressor and condenser are connected to the heat exchanger and the pressure reducer. The refrigerant passes through the evaporator, the evaporator, and then returns to the compressor, while at the time of defrosting the evaporator, the refrigerant flows from the compressor and condenser to the evaporator, the pressure reducer, and the heat exchanger again. A switching valve is provided to form a path for refrigerant returning to the compressor.

(Embodiment) FIG. 1 is a cross-sectional view showing a case where a refrigeration system according to an embodiment of this invention is applied to an open shower case. As shown in the figure, a store case body 1 is provided with a storage chamber 2 for storing products therein, and has an opening 3 formed on the top surface for taking products in and out. On both sides of this opening 3, there are air suction ports 5 for sucking in the cold air flow 4;
An air outlet 6 for blowing out the cold air flow 4 is formed to face the air outlet 6 . Also, a ventilation passage 7 runs from the air suction port 5 to the air outlet 6 through the bottom back side of the storage chamber 2.
Inside, a blower 8 for producing circulating air, a refrigerator heat exchanger 9 for cooling the circulating air during defrosting, and a refrigerator evaporator 10 for cooling the circulating air during normal operation are arranged. be done. Also,
Inside the floor stand 11, a condenser 12 and a compressor 13 of the refrigerator are arranged.

FIG. 2 or FIG. 3 are piping diagrams of the above-mentioned refrigerator, respectively, and the refrigerant movement route is shown by a thick line. Note that FIG. 2 shows a state during normal operation, and FIG. 3 shows a state during defrosting of the evaporator 10. As shown in FIG. 2, the outlet of the compressor 13 is connected to the condenser 12,
The outlet of the condenser 12 is connected via the liquid valve 14 to a first opening 15a of a four-way valve 15, which is a switching valve, and the second opening 15b of the four-way valve 15 is connected to the inlet of the heat exchanger 9. The outlet of the heat exchanger 9 is a check valve 1
6 and expansion valve 17 or through expansion valve 18
and is connected to the evaporator 10 via a check valve 19. The outlet of the evaporator 10 is the third opening 1 of the four-way valve 15.
5c, and the fourth opening 15d of the four-way valve 15 is connected to the inlet of the compressor 13. Further, a bypass valve 20 is provided between the inlet and outlet of the heat exchanger 9 in parallel with the heat exchanger 9. This bypass valve 2
0 opens and closes in conjunction with the temperature of the heat exchanger 9,
The heat exchange amount of the refrigerant by the heat exchanger 9 is controlled according to the temperature of the heat exchanger 9. The four-way valve 15 communicates with the first opening 15a and the second opening 15b, and the third opening 15c and the fourth opening 15d, as shown in FIG. 2 during normal operation, and communicates with the fourth opening 15d as shown in FIG. 3 during defrosting. As shown, it is configured to be switchable so that the first opening 15a and the third opening 15c and the second opening 15b and the fourth opening 15d are communicated with each other.

During normal operation in Fig. 2, the four-way valve 15
The first opening 15a and the second opening 15b communicate with each other,
The third opening 15c and the fourth opening 15d are switched to communicate with each other. Thereby, a refrigerant path is formed from the compressor 13 and condenser 12, through the heat exchanger 9, the expansion valve 17, and the evaporator 10, and then returning to the compressor 13 again. At this time, the high-pressure hot gas compressed by the compressor 13 radiates heat and liquefies in the condenser 12, and the liquid refrigerant that has been supercooled in the heat exchanger 9 is throttled and expanded in the expansion valve 17 and circulated in the evaporator 10. It absorbs the heat of the air and evaporates. In this way, the evaporator 10 cools the circulating air. By the way, during normal operation, the heat exchanger 9 performs the function of subcooling the liquid refrigerant and acts in the direction of warming the circulating air, but when the temperature of the heat exchanger 9 rises above a certain temperature, the bypass valve 20 automatically closes. Since the subcooling function of the heat exchanger 9 is suppressed by opening the heat exchanger 9, the amount of heat released by the heat exchanger 9 does not become a load inside the refrigerator.

When defrosting the evaporator 10 in FIG. 3, the four-way valve 15 is switched so that the first opening 15a and the third opening 15c communicate with each other, and the second opening 15b and the fourth opening 15d communicate with each other. Bypass valve 20 is closed. As a result, compressor 13 and condenser 1
2 to evaporator 10, expansion valve 18, and heat exchanger 9
A path is formed for the refrigerant to return to the compressor 13 again through the refrigerant. At this time, the liquid refrigerant obtained through the compressor 13 and the condenser 12 flows into the frosted evaporator 10, and the evaporator 10 is defrosted by the sensible heat of the liquid refrigerant. The liquid refrigerant supercooled by defrosting expands in the expansion valve 18 and evaporates in the heat exchanger 9, thereby cooling the circulating air. In this way, while defrosting the evaporator 10, the heat exchanger 9 cools the circulating air. Therefore, there is almost no increase in the internal temperature due to defrosting.

According to this refrigeration system, the heat exchanger 9 and the evaporator 1
0 in series, and heat exchanger 9 during normal operation.
A refrigerant path is formed from the evaporator 10 to the evaporator 10, and the circulating air is cooled by the evaporator 10. At the time of defrosting, the refrigerant path is reversed to form a refrigerant path from the evaporator 10 to the heat exchanger 9. The heat exchanger 9 cools the evaporator 10 while defrosting the evaporator 10. This makes the piping structure extremely simple, and even if the refrigeration system is made smaller, the cost will not increase.

In the above embodiment, an open type device in which the opening 3 is always open was used as an example, but this invention can also be applied to a reach-in type device in which a door is provided in the opening 3. be.

(Effects of the invention) As described above, according to the refrigeration device of this invention,
The refrigerant path during normal operation is reversed to form the refrigerant path during defrosting, which simplifies the piping structure and allows the circulating air to be cooled while defrosting the evaporator. Therefore, it is possible to prevent the temperature inside the refrigerator from rising during defrosting.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a refrigeration system as an embodiment of this invention, and FIGS. 2 and 3 are piping diagrams of a refrigeration machine as an embodiment of this invention. 3... Opening, 5... Air suction port, 6... Air outlet, 7... Ventilation path, 9... Heat exchanger, 1
0... Evaporator, 12... Condenser, 13... Compressor, 15... Four-way valve, 17, 18... Expansion valve (pressure reducer).

Claims (1)

[Scope of utility model registration request] In a refrigeration system having an air curtain at an opening, a heat exchanger and an evaporator are arranged in series in a ventilation passage from an air inlet to an air outlet of the air curtain, and A compressor, a condenser, and a pressure reducer are provided, and during normal operation, a refrigerant path is formed from the compressor and condenser to the heat exchanger, the pressure reducer, and the evaporator, and returns to the compressor again. Refrigeration characterized in that a switching valve is provided to form a path for refrigerant from the compressor and condenser to the evaporator, the pressure reducer, the heat exchanger, and back to the compressor during defrosting of the evaporator. Device.