JP6511710B2 - Refrigeration system - Google Patents

Description

  The present invention relates to a refrigeration system, and more particularly, to a refrigeration operation while being able to cope with various operation modes of refrigeration operation and defrost operation when a plurality of load coolers are installed in the same storage. Refrigeration system capable of speeding up the start of the defrosting operation without increasing the load on the vehicle.

  In a cooling system for cooling a load cooler by a cooling circuit in which a cooling refrigerant flows by sequentially connecting a load cooler, a compressor, a heat accumulator, a condenser, a receiver, and an expansion valve in this order by a refrigerant pipe, In order to perform defrosting of the cooled load cooler, from the viewpoint of energy saving, natural heat by loop thermosiphon is used as a refrigeration system or an air conditioner that performs defrosting using exhaust heat during cooling operation. A technique of performing defrosting by circulation is disclosed, for example, in Patent Document 1.

In this refrigeration system, a load cooler, a compressor, a heat storage, a condenser, a receiver, and an expansion valve are sequentially connected by a refrigerant pipe in this order to form a cooling circuit in which a cooling refrigerant flows, Furthermore, a defrost circuit is provided which circulates between the load cooler and the heat accumulator, and the defrost circuit has a heat absorbing portion for receiving heat from the heat storage agent in the heat accumulator, and a load cooler. Inside the heat storage unit, the cooling circuit has a heat release unit that releases heat to the heat storage agent in the heat storage unit, and a cooling unit that cools the load fluid in the load cooler, Is installed at a level lower than the load cooler, and the heat transfer path for the defrost heat medium flowing from the heat accumulator to the load cooler flows from the load cooler to the heat accumulator. , Are provided with the backward defrosting flows defrosting heat medium cooled by the defrost unit.

According to the refrigeration apparatus having such a configuration, during the cooling operation, the refrigerant gas evaporated by cooling the load cooler is compressed by the compressor and dissipated in the heat accumulator, as a result, the heat is stored, and the refrigerant gas is Alternatively, the refrigerant liquid is cooled or condensed by the condenser, and the refrigerant liquid is received by the receiver, and the expansion circuit is cooled to configure the cooling circuit for cooling the load cooler again, thereby cooling the load cooler. .
On the other hand, during the defrosting operation of the load cooler, the heat medium gas for defrosting is sent from the heat accumulator to the load cooler by utilizing the heat stored in the heat accumulator during the cooling operation of the load cooler, while the load cooling Between the heat storage fluid located on the lower side and the load cooling device located on the cold side located above by returning the heat transfer medium fluid for defrosting resulting from the defrosting of the load cooler from the storage unit to the storage unit. By constructing a loop type thermosyphon by circulation, it is possible to defrost while achieving energy saving by enabling defrosting in a state where the compressor is stopped.

However, in such a refrigeration system, the following technical problems are caused due to the occurrence of a single tube thermosyphon phenomenon during refrigeration operation.
Here, the single tube thermosyphon phenomenon is to cause natural circulation due to a heat transport type by phase change between the high temperature portion located below and the low temperature portion located above.

In this case, although it is possible to switch between the freezing operation and the defrosting operation by a single switching valve installed in the forward pipe for defrosting, which transfers the heat medium gas for defrosting from the heat accumulator to the load cooler, If a check valve enabling only the flow from the load cooler to the heat accumulator is provided at a level lower than the liquid level of the defrosting heat medium in the return path for defrosting when the refrigeration system is stopped, the single-tube thermosiphon A phenomenon may occur.
More specifically, a check valve that blocks the flow of refrigerant from the heat accumulator to the load cooler in the return path through which the heat medium for defrosting cooled by the defroster flows from the load cooler to the heat accumulator. However, although it is provided outside the freezer, it is unclear at what level the check valve is installed with respect to the liquid level of the heat medium for defrosting in the return path for defrosting when the refrigeration system is stopped, If the check valve is installed at a level lower than the liquid level of the heat medium for defrosting in the return path for defrosting at the time of stopping the refrigeration system, the freezer compartment wall and liquid of the return path for defrosting more accurately At the portion between the surface and the surface, the heat medium for defrosting is evaporated by heating, and it is cooled and condensed in the freezer, and a waste heat load is input to the load cooler side, and the heat is transferred to the load cooler. Caused by increased heat load , Reduced efficiency of the freezing operation occurs.
If such a check valve is not installed, the heat transfer medium gas flows back from the heat storage unit to the load cooler, so that unnecessary heat load is input to the load cooler side, and the heat transfer medium liquid from the load cooler By returning to the heat accumulator, temperature decrease on the heat accumulator side causes an increase in the defrost time, in addition to an increase in the heat load on the load cooler.

With regard to prolonging the defrost time, the saturation temperature of the heat medium for defrosting is lowered before the start of the defrost operation due to the temperature decrease on the heat storage unit side, and the start of the defrost operation is delayed due to it, and the defrost time is prolonged Occurs.
Prolonged defrosting time is a significant problem, especially when multiple load coolers are installed in the same cabinet.
More specifically, in the normal operation, in order to prevent the temperature rise in the storage compartment, one of the plurality of load coolers is operated for defrosting, except in the case of performing maintenance and inspection simultaneously for the plurality of load coolers. And perform the refrigeration operation (heat storage operation) for other load coolers. Therefore, since the time which can be allocated to the freezing operation (heat storage operation) becomes shorter as the number of load coolers installed in the refrigerator increases, prolonging the defrost time becomes a serious problem.

At that time, a plurality of air coolers may be connected in parallel to a single cooling circuit, and any one of the plurality of air coolers may be operated while the other air coolers are operated for defrosting. If the cooling refrigerant and the heat medium for defrosting are shared at the same time, it is complicated to properly adjust the amount of cooling medium for each system when partitioning the defrosting operation system and the cooling operation system, and the defrost operation It is difficult to secure the necessary amount of heat medium for defrosting, and the defrosting time may be further prolonged due to the shortage of the heat medium for defrosting, and it is possible to cope with various operation modes of freezing operation and defrosting operation. Is difficult.

JP 2014-231921

  In view of the above technical problems, in the case where a plurality of load coolers are installed in the same storage, it is an object of the present invention to make it possible to cope with various operation modes of the freezing operation and the defrosting operation. An object of the present invention is to provide a refrigeration system capable of speeding up the start of defrosting operation without increasing the load on the operation.

In order to achieve the above-mentioned subject, the freezing device of the present invention,
Furthermore, each of the load coolers is provided with a cooling air inflow opening and a cooling air outflow opening, which are disposed opposite to each other, and inside the cooling air flow path from the cooling air inflow opening to the cooling air outflow opening. With the provided casing,
A cooling heat transfer pipe which is disposed in the casing so as to cross an air flow along the ventilation flow channel and in which an air cooling refrigerant flows;
And a heat transfer pipe for defrosting, in which a heat transfer medium for defrosting flows, provided independently of the heat transfer pipe for cooling in the casing.
In the heat transfer pipe for cooling, one end opening and the other end opening are respectively connected to an air cooling refrigerant inflow opening and an air cooling refrigerant outflow opening provided in the casing,
In the heat transfer tube for defrosting, one end opening and the other end opening are respectively connected to the heat medium inflow opening for defrosting and the heat medium outflow opening for defrosting provided in the casing, and the heat transfer tube for defrosting is in the casing Wherein the heat transfer tube for cooling is disposed so as to be defrostable in an external heating system,
An inlet-side refrigerant branch pipe and an outlet-side refrigerant branch pipe are connected to the air cooling refrigerant inflow opening and the air cooling refrigerant outflow opening, and the defrosting heat medium inflow opening and the defrosting heat medium outflow opening are connected to each other. The inlet side heat medium branch pipe and the outlet side heat medium branch pipe may be connected.

A first embodiment of a refrigeration apparatus according to the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, the refrigeration system 10 includes a load cooler 12, a compressor 14, a heat accumulator 16, a condenser 18, a receiver 17, and an expansion valve 151 sequentially connected by a refrigerant pipe in this order to internally A defrost circuit 72 independent of the cooling circuit 70 that circulates between the load cooler 12 and the heat accumulator 16 is provided, and the defrost circuit 72 is internally provided with a heat medium for defrosting. In the heat accumulator 16, the heat absorption part 74 which absorbs heat from the heat storage agent, and the defrost part 76 which radiates heat in the load cooler 12 are provided.

On the other hand, the cooling circuit 70 has a heat radiating portion 78 which radiates heat to the heat storage agent in the heat accumulator 16 and a cooling portion 80 which cools the load fluid in the load cooler 12.
As a result, the load fluid is cooled by the cooling unit 80 through the cooling circuit 70 and dissipated to the heat storage agent through the heat radiating unit 78, while the heat absorption unit 74 absorbs heat from the heat storage through the defrost circuit 72. The load cooler 12 is configured to be defrosted via the portion 76.

In the defrost circuit 72, the heat accumulator 16 is installed at a lower level than the load cooler 12, and the heat transfer medium for defrosting heated by the heat absorber 74 flows from the heat accumulator 16 toward the load cooler 12; A defrost return path 84 through which the defrosting heat medium cooled by the defrost unit 76 flows from the load cooler 12 toward the heat accumulator 16 is provided. In the defrost return path 84, a check valve 140 is provided in the freezer 200, and as will be described later, a part of the load coolers 12 performs a cooling operation, and other load coolers 12 connected in parallel are connected. In the defrosting operation, the heat medium for defrosting is prevented from flowing into the load cooler 12 during the cooling operation.

On the other hand, in the cooling circuit 70, a cooling forward passage 155A connecting the water cooling condensing unit 81 and the load cooler 12, a cooling return passage 153A connecting the load cooler 12 and the water cooling condensing unit 81, and water cooling A heat storage forward path 147A connecting the type condensing unit 81 and the heat accumulator 16 and a heat storage return path 147B connecting the heat accumulator 16 and the water-cooled condensing unit 81 are provided.
Thereby, by utilizing the heat stored during the cooling operation of the load cooler 12 in the heat accumulator 16, the heat medium gas for defrosting is sent from the heat accumulator 16 to the load cooler 12, while the heat is stored from the load cooler 12 The loop thermosyphon is configured to return the heat transfer fluid for defrosting resulting from the defrosting of the load cooler 12 to the vessel 16.

The installation level difference H relative to the load cooler 12 of the heat storage unit 16 (more accurately, the liquid surface of the heat transfer medium for defrost in the liquid receiver 20 described later) is a viewpoint of forming a loop type thermosyphon Therefore, it may be determined appropriately. The heat storage agent of the heat storage 16 may be a latent heat storage agent or a sensible heat storage agent. For example, the latent heat storage agent is paraffinic, and the sensible heat storage agent is water.
The water cooling condensing unit 81 is provided with a cooling water return pipe 145A and a cooling water supply pipe 145B, and is used for condensation of the refrigerant by the condenser 18.

The load coolers 12 are provided in a plurality of (two in FIG. 1) freezers 200 and are connected in parallel to the cooling circuit 70 via the inlet side refrigerant branch pipe 86 and the outlet side refrigerant pipe 88, The defrost circuit 72 is connected in parallel via an inlet-side heat medium branch pipe 90 and an outlet-side heat medium branch pipe 92.
As shown in FIG. 1, the load coolers 12A and 12B of the two load coolers 12 are installed, for example, on the second floor of a building, and the load coolers 12A and 12B are installed at the same level.

In the cooling forward passage 155A, switching valves 220A and 220B are provided on the branch pipes to the load coolers 12A and 12B on the upstream side of the expansion valves 151A and 151B, the switching valve 220A is opened, and the 220B is closed. Thus, only the load cooler 12A is cooled, the switching valve 220A is closed, and the switching valve 220B is opened, whereby only the load cooler 12B is cooled, the switching valve 220A is opened, and the opening 220B is opened. , And the load coolers 12A and 12B are operated for cooling.
A switching valve is provided in each of the defrosting heat medium pipes (the defrosting passage 82 and the defrosting passage 84) from the viewpoint of switching between the normal operation mode and the defrost operation mode, as described below.

More specifically, the heat medium for defrosting to the load coolers 12A and 12B is cooled in the outward path 82 for defrosting, from the viewpoint of preventing the so-called single tube thermosyphon phenomenon from occurring in the outward path 82 for defrosting. The switching valves 94C and 94D are the heat mediums for defrosting of the switching valve 94A in order to switch the heating medium for defrosting to the load cooler 12A and the heating medium for defrosting to the load cooler 12B, provided with the switching valve 94A. It is provided closer to the flow direction load cooler 12. By opening the switching valve 94C and closing 94D, only the load cooler 12A is in a defrosting operation, the switching valve 94D is opened and the load 94C is closed. By defrosting only the cooler 12B and opening both of the switching valves 94C and 94D, the load coolers 12A and 12B are deflated. So that the door operation.

At the level between the load coolers 12A and 12B of the return path 84 for defrost and the heat accumulator 16, a receiver 20 provided with a liquid level gauge 149 is provided, and as will be described later, At the time of defrosting operation, the heat medium for defrosting heats the load cooler 12 as a heat medium gas to become a heat medium fluid, and the liquid level in the heat medium fluid for the defrosting passage 82 and the defrosting passage 84 is The receiver 20 is provided so that the stability of the defrosting operation is not impeded by the fluctuation of the liquid level because it may fluctuate depending on the state of the heat accumulator 16 and / or the load cooler 12 . Note that the level of the receiver 20 is lower than the load coolers 12A and 12B from the viewpoint of achieving a natural circulation by the loop thermosiphon by securing a level difference with the heat accumulator 16 as will be described later. , As close as possible to the level of the load coolers 12A and 12B.

  Outside the freezer 200 in which the load coolers 12A and 12B are installed in the return path 84 for defrosting, a check valve 206 that allows only the flow from the load cooler 12 to the heat accumulator 16 is the refrigerator 10 It is provided at a level above the liquid level of the heat medium for defrosting in the return path 84 for defrosting at the time of stop of, that is, at a level above the liquid level of the receiver 20. As a result, as will be described later, the occurrence of the so-called single tube thermosyphon phenomenon in the defrost return path 84 is avoided. More specifically, the single-tube thermosyphon phenomenon, which is generated by the heat transfer medium gas for defrosting heated in the heat accumulator 16 flowing back to the return path 84 for defrosting in the freezer 200, is avoided to avoid an increase in cooling load. There is. From this point of view, it is preferable that the position of the check valve 206 be outside the freezer 200 and as close as possible to the load cooler 12.

Furthermore, a bypass pipe line 202 is provided to connect between the defrosting path 82 and the defrosting path 84, and an on / off valve 204 is provided in the bypass pipe 202. More specifically, a portion between the switching valve 94A of the outward path 82 for defrosting and the heat accumulator 16 and a portion between the check valve 206 of the backward path 84 for defrosting and the liquid receiver 20 are bypass conduits 202. Are connected and the on-off valve 204 is closed in the freezing operation and the defrosting operation which will be described later, thereby preventing the heat medium gas for defrosting from bypassing from the outward passage 82 for defrosting to the return passage 84 for defrosting. In the preparatory operation, the on / off valve 204 is opened, so that the check valve 206 is heated in the heat accumulator 16 while suppressing the flow of the heat medium gas for defrosting in the heat accumulator 16 to the load cooler 12. A loop type thermosy that returns the defrosting heat carrier gas to the heat accumulator 16 via the receiver 20 via the bypass pipe 202 So that emissions are formed.

The load cooler 12 is installed in a refrigerator, for example, to cool the inside of the freezer 200 or the inside of a cold storage, a shipping room or the like.
As shown in FIG. 2, each of the load coolers 12 is, for example, a unit cooler fixed to the ceiling in the cold storage via a lifting bracket 117 with a lifting bolt and a nut, and the cooling air inlet openings arranged opposite to each other And a cooling air outlet opening, and a casing 102 provided therein with a ventilation channel 100 extending from the cooling air inlet opening toward the cooling air outlet opening. A blower 101 is provided on a pair of opposing side surfaces of the casing 102. The number 103 is a terminal box in which the terminals of the blower 101 are wired.

In the casing 102, a heat transfer pipe 104 for cooling is disposed so as to cross an air flow along the ventilation flow passage 100, and a refrigerant for air cooling flows therein, and in the casing 102, independently of the heat transfer pipe 104 for cooling. The heat transfer tubes 106 for defrosting are provided in parallel with each other in a non-contact manner, and the heat transfer tubes 104 for cooling and the heat transfer tubes 106 for defrosting are respectively provided as follows, It is comprised by connecting the U-tube part arrange | positioned to the outer side of each opposing partition plate 120 of the casing 102, and the straight pipe part extended between the opposing partition plates 120. As shown in FIG.

The cooling heat transfer pipe 104 is connected to the cooling forward passage 155 downstream of the expansion valve 151 via the flow divider 141 and the inlet-side refrigerant branch pipe 86 branched from the flow divider 141, while the cooling return passage The outlet 153 is connected via an outlet-side refrigerant pipe 88.
In the heat transfer pipe 106 for defrosting, it is connected downstream of the switching valve 94 to the outward path 82 for defrosting via the inlet-side heat medium branch pipe 90 (FIG. 1). It is connected via a side heat medium branch pipe 92 (FIG. 1).

As shown in FIG. 3, each of the opposing partition plates 120 of the casing 102 is provided with a large number of through holes 123, and the heat transfer tube 106 for defrosting is a straight line for defrosting extending between the opposing partition plates 120 in the casing 102. It has a tube portion 124 and a defrosting U-shaped tube portion 126 that connects the straight tubes 124 for defrosting via the through holes 123 outside the partition plate 120.

The cooling heat transfer pipe 104 connects the cooling straight pipe portion 128 extending between the opposing partition plates 120 in the casing 102 and the cooling straight pipe portions 128 outside the partition plate 120 via the through holes 122 And U-shaped tube portion 130 (FIG. 2).
More specifically, as shown in FIG. 3, the heat medium in the defrosting pipe is collected in the inlet header 107 and branched therefrom by a branch pipe (four branches in the figure), and the opposing partitions in each branch pipe A U-shaped bend pipe 126 for defrosting provided on one of the partition plates of the plate 120, a straight pipe portion for defrosting 124 extending between the opposing partition plates 120, and a U for defrosting provided on the other partition plate of the opposing partition plate 120 The through-holes 123, which are formed by the V-shaped bend pipes 126 and are arranged in the vertical direction and the horizontal direction respectively provided in the partition plates 120, are connected for jumping in the vertical direction (for two in the drawing) for defrosting A U-shaped bend tube 126 is provided, each branch tube being collected at the outlet header 109 and connected therefrom to the tubing 84.

On the other hand, the refrigerant in the cooling pipe is collected in the flow divider 141 and branched therefrom by the inlet-side refrigerant branch pipe 86 (six branches in the figure), and in each branch pipe, one partition plate of the opposing partition plates 120 The cooling U-shaped bend pipe 130 provided in the first embodiment, the cooling straight pipe portion 128 extending between the facing partition plates 120, and the cooling U-shaped bend pipe 130 provided in the other partition plate of the facing partition plates 120 The cooling U-shaped bend pipes 130 are provided to be connected in a splattering manner, if necessary, with respect to the through holes 122 arranged in the vertical direction and the horizontal direction respectively provided in each partition plate 120, and each branch pipe is an outlet header It is collected at 105 and connected to the cooling return path 153 from there.

In the casing 102, plate-like fins 132 for the heat transfer pipe 104 for cooling are further provided, and in the plate-like fins 132, a large number of through holes 122 and 123 are provided at the same position as the partition plate 120. A plurality of plate-like fins 132 are provided in parallel with each other so as to be orthogonal to the ventilation channel 100, respectively.
In this case, the plate-like fins 132 having the function of expanding the heat transfer area of the heat transfer pipe for cooling 104 are used for supporting the heat transfer pipe for defrosting 106 together with the heat transfer pipe for cooling 104.
The straight pipe portions 128 of the cooling heat transfer pipe 104 and the straight pipe portions 124 of the heat transfer pipe 106 for defrosting are fixed to the plate-like fins 132 in a manner to penetrate through the through holes 122 and 123, whereby the transmission for defrosting From the heat pipe 106, the plate-like fins 132 and the heat transfer pipe 104 for cooling are configured to be defrosted in the form of heat radiation or heat conduction.

  The temperature of the cooling refrigerant is, for example, -10 ° C, whereby the air is cooled from normal temperature to -5 ° C, while the temperature of the heat medium for defrosting is 20 ° C, whereby the inside of the load cooler 12 is The defrosted frost is defrosted (to be described later).

As shown in FIG. 3, a heat transfer pipe 106 for defrosting is disposed with respect to a drain pan 134 disposed below the casing 102 for receiving a liquid generated at the time of defrosting, and a forward path 82 for defrosting connected to the heat transfer pipe 106 for defrosting. And a heat transfer pipe 135 for defrosting which is routed in a downward slope so as to contact the bottom surface 137 of the drain pan 134 in a contact manner, and provided with a branch pipe 136 branched on the upstream side of The entire bottom surface 137 of the drain pan 134 is heated in a thermally conductive form through the heat transfer pipe 135 and is configured to be defrostable. The defrosting heat transfer pipe 135 is connected to the defrosting return path 84 downstream of the outlet header 109.
The heat transfer pipe 106 for cooling and the refrigerant pipe 104 for cooling are both preferably copper pipes from the viewpoint of heat conductivity and cost, and in some cases, they may be aluminum pipes or stainless pipes, and the material of the plate-like fins 132 is heat For transmission priority, aluminum is preferable. In some cases, copper or stainless steel may be used, and the casing is, for example, a galvanized steel plate, and the drain pan is SUS.

As a modification, in the case of using the existing load cooler 12, a defrost electric heater in which a heating coil is wired is provided inside the casing 102, and the heating coil penetrates the opposing partition plate 120 of the casing 102. In the case of modifying the load cooler 12 based on the through hole (not shown), the through hole through which the heating coil penetrates is used for defrosting instead of the electric heater for defrosting. The heat transfer tube 106 may be provided.
Thereby, along with providing the heat transfer pipe for defrosting separately, it is possible to prevent the load cooler 12 from being enlarged.

The operation of the refrigeration apparatus 10 having the above configuration will be described below through the description of the method of operating the refrigeration apparatus 10 with reference to FIGS. 4 to 6.
The operation method of the refrigeration apparatus 10 is divided into a normal cooling operation mode (heat storage phase) (FIG. 4), a defrost preparation operation mode (FIG. 5) and a defrost operation mode (FIG. 6) as operation modes.
A normal cooling operation mode (heat storage phase) is performed for load coolers 12A and B, and then a defrost operation mode is performed for load cooler 12A through a defrost preparation operation mode, and a normal cooling operation mode for load cooler 12B. Next, the case where the normal cooling operation mode is performed for the load cooler 12A while the defrost operation mode is performed for the load cooler 12B will be described as an example.

First, as shown in FIG. 4, in the normal cooling operation mode (heat storage stage), the switching valves 94A, C and D, and the on / off valve 204 are closed, the switching valves 220A, B are opened, and the compressor 14 is operated. .
The refrigerant flows from the load coolers 12A and B into the compressor 14 through the cooling return path 153A, is compressed here, and further flows from the compressor 14 into the heat storage machine 16 through the heat storage forward path 147A, where The refrigerant dissipates heat, is stored in the heat storage unit 16, and flows from the heat storage unit 16 into the condenser 18 through the heat storage return path 147B, where it is condensed or subcooled and further expanded from the condenser 18 through the cooling forward path 155A. It flows into the valves 151A, B, where the degree of superheat of the refrigerant is adjusted by adjusting the degree of opening of the expansion valves 151A, B, and further the load cooler from the expansion valves 151A, B via the flow dividers 141A, B It returns to 12A and B and is trying to comprise a cooling circuit.

As described above, the refrigerant flows as shown by the arrows in FIG. 4 and is in a gas state from the load cooler 12 to the heat accumulator 16 via the compressor 14, in particular, the load cooler 12 and the compressor 14 and During the low pressure gas state, while the high pressure gas state between the compressor 14 and the heat accumulator 16, while the liquid or wet steam state from the heat accumulator 16 to the load cooler 12 via the expansion valve 151 It is.

Next, as shown in FIG. 5, in the defrost preparation operation mode, the on / off valve 204 is opened to prevent the reverse flow of the heat medium for defrosting to the load cooler 12 side through the return path for defrosting 84 by the check valve 206 A loop type in which the heat transfer medium for defrosting is returned from the heat transfer path for defrosting 82 to the return flow for defrosting 84 so that a part of the heat transfer path 16 from the heat storage 16 is returned to the heat storage 16 by the bypass pipe 202 and a part of the heat return path 84 By forming a thermal siphon, it is possible to prevent a decrease in the saturation temperature of the heat medium for defrosting, and thereby speed up the start-up at the start of the defrosting operation.
In addition, since there is a heat medium for defrosting at a high temperature in the heat accumulator 16 positioned at a level lower than the liquid receiver 20, a loop-type thermal siphon is formed, but the heat medium for defrosting is used by the loop-type thermal siphon until the defrost operation starts Need not be circulating.

Next, as shown in FIG. 6, in the defrosting operation mode, the switching circuit 220B is kept open while the compressor 14 is not stopped for the cooling circuit, while the switching valve 220A is closed, and the load cooler 12B is closed. In the defrosting circuit, the switching valves 94A and C are opened, the switching valve 94D is kept closed, and the defrosting operation of the load cooler 12A is performed.
More specifically, the heat transfer medium gas for defrosting (heat absorption) evaporated by the heat storage of the heat storage unit 16 flows from the forward path 82 for defrosting to the load cooler 12A, and here the heat transfer medium gas for defrosting condenses (radiates) As a result, the load cooler 12A is defrosted, the defrosting adhering to the load cooler 12A is performed, and the heat transfer medium for defrost is returned to the heat accumulator 16 through the return path 84 for defrosting, and this natural circulation is repeated. A loop type thermosyphon is configured to defrost the load cooler 12A.

In this case, as in the conventional case, when the heat transfer pipe 104 for cooling is used commonly for cooling and for defrosting and the heat medium for defrosting is made to flow internally, the refrigerant for cooling flows by flowing internally for cooling. Since frost is formed on the outer peripheral surface of the heat transfer tube 104, heat is effectively radiated outward from the outer peripheral surface of the cooling heat transfer tube 104 unless the frost formed on the outer peripheral surface is melted. It is difficult to transmit, and the liquid defrosted by the heat conduction form is prevented from being recooled and refreezing in the form of an ice column by leaving the plate-like fins 132 and the outer peripheral surface 106 of the cooling heat transfer tube 104. It will be difficult. As a result, when the air flow passage 100 for air to be cooled is formed between the adjacent plate-like fins 132, the flow passage area of the air flow passage 100 is narrowed, and the deterioration of the cooling capacity is caused.

In this point and this time, in the load cooler 12, the heat transfer pipe 106 for defrosting is separately provided from the heat transfer pipe 104 for cooling, and the outer peripheral surface 105 of the heat transfer pipe 104 for cooling and the outer peripheral surface of the heat transfer pipe 106 for defrosting are By setting the distance to a predetermined distance, the heat medium for defrosting flowing inside the heat transfer tube for defrosting 106 transfers heat in a heat conduction mode through the plate-like fins 132 and the heat transfer tube for defrosting 106 with a small degree of frost formation. It is possible to effectively prevent refreezing of the defrosted liquid by transferring heat from the outer peripheral surface of the heat sink in the form of heat radiation.
From such a point of view, the distance between the outer peripheral surface of the cooling heat transfer tube 104 and the outer peripheral surface of the defrosting heat transfer tube 106 is the temperature of the outer peripheral surface of the cooling heat transfer tube 104, the temperature of the outer peripheral surface of the defrosting heat transfer tube 106, It may be determined appropriately according to the heat medium flow rate and the distance between the adjacent plate-like fins 132.
While the defrosting of the load cooler 12A is being performed by the defrosting operation, the load cooler 12B is continuing the freezing operation, whereby the temperature in the freezer 200 is increased by the defrosting operation of the load cooler 12A. The heat storage to the heat accumulator 16 is performed by the freezing operation of the load cooler 12B.

Then, when defrosting of the load cooler 12A is completed, as shown in FIG. 7, the switching valve 220A is opened while the switching valve 220B is closed without stopping the compressor 14 for the cooling circuit, and the load cooler 12A is closed. In the defrost circuit, the switching valve 94D is opened, the switching valve 94C is closed, and the open state of the switching valve 94A is maintained, so that the defrosting operation of the load cooler 12B is performed.
More specifically, as described above, while performing the refrigeration operation of the load cooler 12B, the load operation is performed while the refrigeration operation of the load cooler 12A is performed similarly to the defrost preparation operation and the defrost operation performed for the load cooler 12A. Since the defrost preparation operation and the defrost operation are performed for the cooler 12B, the repeated description is omitted.

  The timing of switching to the defrost operation may be switched manually as appropriate according to the state of frost generation in the load cooler 12, or the load in the load cooler 12 is relatively constant, and the progress of frost is relatively If it is regular, the timer may be set in advance to switch automatically, or the temperature of the heat transfer tube (not shown) of the load cooler 12 may be detected and the detected temperature may be used. It may be set.

  As a modified example of the operation method, when the temperature rise in the freezer / freezer 200 due to the defrost operation does not matter, for example, in the state where there is no object to be frozen in the freezer / freezer 200, the load coolers 12A and B are simultaneously defrosted and operated. May be In this case, in a state where the heat amount necessary for defrosting the load coolers 12A and 12B is stored in the heat accumulator 16, the compressor 14 may be stopped without performing the refrigeration operation concurrently with the defrost operation, or In the situation where the heat storage necessary for defrosting either of the load coolers 12A and 12B is stored in the heat storage unit 16, the refrigeration operation is performed concurrently with the defrosting operation for either of the load coolers 12A and 12B. While storing heat, defrost operation may be performed.

According to the refrigeration system having the above configuration, during the cooling operation, the refrigerant gas evaporated by cooling the load cooler 12 is compressed by the compressor 14 and dissipated in the heat accumulator 16 as a result of which it is stored. The refrigerant gas or the refrigerant liquid is condensed or subcooled in the condenser 18, and the refrigerant liquid passes through the expansion valve 151 to configure the cooling circuit for cooling the load cooler 12 again, thereby cooling the load cooler 12.
On the other hand, during the defrosting operation of the load cooler 12, the heat stored in the heat storage unit 16 is utilized during the cooling operation of the load cooler 12 to transfer the heat storage unit 16 to the load cooler 12 through the defrosting passage 82. And sends the heat medium gas for defrosting, while returning the heat medium fluid for defrosting resulting from the defrosting of the load cooler 12 from the load cooler 12 to the heat accumulator 16 via the return path 84 for defrosting, it is positioned downward. It is possible to form a loop type thermosiphon by natural circulation between the hot side heat accumulator 16 and the cold side load cooler 12 located above.
In particular, the check valve 206 which allows only the flow from the load cooler 12 to the heat accumulator 16 in the return path 84 for defrosting is a liquid of the heat medium for defrosting in the return path 84 for defrosting when the refrigeration system 10 is stopped. Since the heat medium for defrosting is provided at a level above the order, the backflow from the heat accumulator 16 to the defrosting path 84 in the freezer 200 is prevented via the defrosting condenser 84, and the heat medium gas for defrosting is accumulated. By flowing back from the heater 16 to the defrost return path 84 in the freezer 200, unnecessary heat load is input to the freezer 200, and the heat transfer fluid for defrost is transferred from the defrost return path 84 in the freezer 200 to the heat accumulator 16. The temperature decreases on the heat accumulator 16 side by returning, so that the load cooling is performed by the single tube thermosyphon phenomenon in the so-called defrosting condenser 84. And increased defrosting time of the heat load to 12 from prolonged is triggered can be prevented.
As shown in FIG. 8A, conventionally, when switching from the freezing operation to the defrosting operation, even if heat is stored in the heat storage unit 16 during the cooling operation, the heat medium gas from the heat storage unit 16 from the load cooler 12 Since it is possible to back flow through the heat transfer fluid to the heat storage unit 16 through the defrosting return pipe 84, a single-pipe thermosyphon phenomenon occurs in the heat recovery condenser 84, and the heat transfer gas is stored in the heat storage unit 16 Back flow to the load cooler 12 so that unnecessary heat load is input to the freezer 200 side, and the temperature of the heat accumulator 16 side decreases due to the heat medium liquid returning from the load cooler 12 to the heat accumulator 16 As a result, the decrease in the saturation temperature of the heat medium for defrosting immediately before the defrosting operation and the prolongation of the defrosting time are caused.
On the other hand, as shown in FIG. 8B, in the present embodiment, the defrost preparation operation is performed during the freezing operation, and in the defrost preparation operation, the check valve 206 is used for defrosting via the defrosting pipe 84 for defrosting. By preventing the backflow of the heat medium, the occurrence of the single tube thermosyphon phenomenon in the defrosting condenser 84 is avoided in advance, and the bypass pipe 82 from the defrosting pipe 82 to the defrosting condenser 84 is bypassed. It is possible to promote the melting of the heat storage agent in the heat accumulator 16 and to suppress the decrease in the saturation temperature of the heat medium for defrost just before the defrost operation by returning the heat medium gas for defrost to the heat accumulator 16 through Therefore, the heat load to the load cooler 12 is increased and the defrost operation time is increased by the quick start-up of the defrost operation. It is possible to effectively prevent the reduction.

Furthermore, according to the refrigeration apparatus 10 having the above configuration, the load cooler 12, the compressor 14, the heat accumulator 16, the condenser 18, the receiver 17, and the expansion valve 151 are sequentially connected by refrigerant piping in this order to cool the inside System reliability is improved by providing a defrost circuit 72 independent of the cooling circuit 70 that circulates between the load cooler 12 and the heat accumulator 16 with respect to the cooling circuit 70 in which the refrigerant flows. However, while being able to cope with various operation modes of the cooling operation and the defrost operation, the defrosting becomes possible without affecting the type of cooling refrigerant and the temperature and pressure conditions.

According to the defrost (defrosting) method of the load cooler 12 having the above configuration, the plurality of load coolers 12, the compressor 14, the heat accumulator 16, the condenser 18, the receiver 17, and the expansion valve 151 connected in parallel to one another In this order, the refrigerant circuit is sequentially connected by refrigerant pipes, and the cooling circuit in which the cooling refrigerant flows internally stores heat through the heat accumulator 16 and cools the load cooler 12, while the defrosting heat medium has a plurality of loads. In the defrost method of the load cooler 12 for radiating heat through the heat accumulator 16 and defrosting the load cooler 12 by a defrost circuit independent of the cooling circuit 12 which circulates between each of the coolers 12 and the heat accumulator 16 , Storing heat in the heat accumulator 16 by performing a cooling operation of any of the plurality of load coolers 12, and the plurality of load coolers 1 One of and a step of operating defrost.
In this case, in the defrosting operation stage, any one of the plurality of load coolers 12 is cooled and the heat is accumulated in the heat accumulator 16 and, at the same time, the remaining one of the plurality of load coolers 12 is defrosted. It may have a step of operating, or, the defrosting phase of operation, while stopping the cooling operation of all of the plurality of load coolers 12, defrosts any one of the plurality of load coolers 12 in parallel. There may be stages, and defrosting is possible without affecting the type of cooling refrigerant and temperature and pressure conditions, while being able to cope with various operation modes of the cooling operation and the defrost operation.

Alternatively, during the cooling operation, the heat storage unit 16 may be bypassed after the heat storage stage is completed.
More specifically, the pressure loss at the heat accumulator 16 is inevitably caused by the discharge refrigerant gas from the compressor 14 flowing to the condenser 18 through the heat accumulator 16, so that such pressure loss is eliminated. For this purpose, a heat accumulator bypass pipe may be provided to connect between the heat storage forward path 147A and the heat storage return path 147B, and the heat accumulator 16 may be bypassed via a heat accumulator bypass pipe (not shown).
In particular, in the normal cooling operation, after sufficient heat storage is performed by the heat accumulator 16, only the cooling operation may be performed by bypassing the heat accumulator 16 via the heat accumulator bypass pipe.

A second embodiment of the refrigeration system according to the present invention will be described in detail below with reference to the drawings.
In the following description, constituent elements similar to those of the first embodiment are denoted by the same reference numerals and descriptions thereof will be omitted, and in the following, features of the present embodiment will be described in detail.
The feature of the second embodiment of the present invention is that in the first embodiment, a plurality of load coolers are separated and independently provided with a defrost circuit and a cooling circuit, while a single load is provided. The point is that the defrost circuit and the cooling circuit are shared for the cooler.
Embodiments of a refrigeration apparatus according to the present invention will be described in detail below with reference to the drawings.
As shown in FIG. 9, the refrigerating apparatus 10 sequentially connects a load cooler 12, a compressor 14, a heat accumulator 16, a condenser 18, a receiver 20, and an expansion valve 22 by a refrigerant pipe in this order to provide a cooling circuit. Configure. A heat accumulator 16 is installed at a level (level difference H) lower than the load cooler 12, and connects a third refrigerant pipe 28 connecting the expansion valve 22 and the load cooler 12, a compressor 14 and the heat accumulator 16. A first bypass pipe 27 connecting the second refrigerant pipe 26, a first refrigerant pipe 24 connecting the load cooler 12 and the compressor 14, and a fourth refrigerant pipe 30 connecting the heat accumulator 16 and the condenser 18. And the connection position of the first refrigerant pipe 24 to the load cooler 12 is lower than the connection position of the third refrigerant pipe 28 to the load cooler 12 (level difference (level difference). h). The condenser 18 and the receiver 20 are connected by a sixth refrigerant pipe 50.
Thereby, the refrigerant gas is sent from the heat accumulator 16 to the load cooler 12 through the first bypass pipe 27 by utilizing the heat stored during the cooling operation of the load cooler 12 in the heat accumulator 16 while the load is A loop thermosyphon is configured to return the refrigerant liquid resulting from the defrosting of the load cooler 12 from the cooler 12 to the heat accumulator 16 via the second bypass pipe 31.
Relative installation level difference H of the heat accumulator 16 to the load cooler 12 and relative position of the connection of the first refrigerant pipe 24 to the load cooler 12 to the position of the third refrigerant pipe 28 to the load cooler 12 The installation level difference h may be appropriately determined from the viewpoint of forming a loop thermosiphon.
Furthermore, a third bypass pipe 42 is provided that connects the fifth refrigerant pipe 40 connecting the liquid receiver 20 and the expansion valve 22 with the heat storage unit 16 side of the second switching valve 34 of the fourth refrigerant pipe 30, A fifth switching valve 44 is provided in the middle of the third bypass pipe 42, and the refrigerant is supplied from the liquid receiver 20 to a part of the fifth refrigerant pipe 40, a part of the third bypass pipe 42 and a part of the fourth refrigerant pipe 30 The liquid is sent to the heat accumulator 16.
Further, a heat accumulator bypass pipe 46 connecting the second refrigerant pipe 26 and the fourth refrigerant pipe 30 is provided, and a sixth switching valve 48 is provided in the middle of the heat accumulator bypass pipe 46.

Each refrigerant pipe (the first refrigerant pipe 24, the second refrigerant pipe 26, the fourth refrigerant pipe 30) is provided with a switching valve from the viewpoint of switching between the normal operation mode and the defrost operation mode as described below. It is done.
More specifically, the first switching valve 32 is provided on the compressor 14 side from the connection position of the first bypass pipe 27 to the second refrigerant pipe 26, and the connection of the second bypass pipe 31 to the fourth refrigerant pipe 30. From the position, the second switching valve 34 is provided on the heat accumulator 16 side, and the third switching valve 36 is provided on the compressor 14 side from the connection position of the second bypass pipe 31 to the first refrigerant pipe 24. A fourth switching valve 38 is provided in the middle of the bypass pipe 27.
As in the first embodiment, only the flow from the load cooler 12 toward the heat accumulator 16 is possible outside the freezer 200 in which the load cooler 12 of the second bypass pipe 31 is installed. The stop valve 206 is provided at a level above the liquid level of the defrosting heat medium in the second bypass pipe 31 when the refrigeration system 10 is stopped. That is, it is provided at a level above the liquid level of the receiver 20. As a result, as in the first embodiment, the occurrence of the so-called single tube thermosyphon phenomenon in the second bypass tube 31 is avoided. More specifically, when switching from the freezing operation to the defrosting operation, the heat transfer fluid for defrosting cooled in the load cooler 12 flows to the heat accumulator 16 so as not to cause a decrease in the saturation temperature of the heat transfer medium for defrosting. Conversely, the defrosting heat transfer medium gas heated in the heat accumulator 16 flows to the load cooler 12 so that the cooling load does not increase.
Furthermore, a bypass line 202 connecting the first bypass line 27 and the second bypass line 31 is provided, and an on / off valve 204 is provided in the bypass line 202. More specifically, the portion of the first bypass pipe 27 between the switching valve 38 and the heat accumulator 16 and the portion of the second bypass pipe 31 between the check valve 206 and the connection to the fourth refrigerant pipe 30 As in the first embodiment, the heat medium gas for defrosting is connected from the first bypass pipe 27 to the second bypass pipe by closing the on-off valve 204 in the freezing operation and the defrosting operation, as in the first embodiment. As in the first embodiment, the on-off valve 204 is opened in the defrost preparation operation while the bypass to the valve 31 is suppressed, so that the defrosting heat medium gas heated in the heat accumulator 16 by the check valve 206 is A loop type in which the defrosting heat medium gas heated in the heat accumulator 16 returns to the heat accumulator 16 through the bypass pipe 202 while suppressing the flow to the load cooler 12 So that over mode siphon is formed.

The load cooler 12 is installed in a refrigerator, for example, to cool the inside of a refrigerator such as a freezer, a cold storage, a shipping room, and the like.
The heat storage agent of the heat storage 16 may be a latent heat storage agent or a sensible heat storage agent. For example, the latent heat storage agent is paraffinic, and the sensible heat storage agent is water.

As described later, in the initial stage of the defrost operation mode, the amount of refrigerant necessary for defrosting the load cooler 12 is naturally supplied from the liquid receiver 20 through the third bypass pipe 42 before defrosting.
More specifically, when the compressor 14 is stopped, the refrigerant in the fifth refrigerant pipe 40 between the liquid receiver 20 and the expansion valve 22 is downstream of the compressor 14 and has a relatively high pressure, In the loop type thermosyphon configured by connecting the load cooler 12 and the heat accumulator 16 by the first bypass pipe 27 and the second bypass pipe 31, the high temperature side heat accumulator 16 and the low pressure side load cooling Because the medium pressure becomes relatively medium by communicating with the vessel 12, it is possible to naturally supply the refrigerant from the receiver 20 to the load cooler 12 by this differential pressure.
As a modification, a pump (not shown) is provided between the liquid receiver 20 of the fifth refrigerant pipe 40 and the branch portion between the third bypass pipe 42 or in the middle of the third bypass pipe 42, whereby defrosting is performed. Alternatively, the amount of refrigerant necessary for defrosting the load cooler 12 may be forcibly supplied from the liquid receiver 20 through the third bypass pipe 42.

The operation of the refrigeration apparatus 10 having the above configuration will be described below through the description of the method of operating the refrigeration apparatus 10 with reference to FIGS. 10 to 14.
Regarding the operation method of the refrigeration apparatus 10, as an operation mode, a normal operation mode 1 (heat storage stage) (FIG. 10), a normal operation mode 2 (after heat storage termination) (FIG. 11), a defrost preparation operation mode (FIG. 12), a defrost operation The operation mode is divided into a mode (initial stage) (FIG. 13) and a defrost operation mode (normal stage) (FIG. 14).

First, as shown in FIG. 10, in the normal operation mode 1 (heat storage stage), the first switching valve 32, the second switching valve 34, the third switching valve 36 and the expansion valve 22 are opened, while the fourth switching valve 38 is The compressor 14 is operated with the fifth switching valve 44, the sixth switching valve 48, and the on / off valve 204 closed.
Note that the fourth switching valve 38 of the first bypass pipe 27 is closed, and the check valve 206 of the second bypass pipe 31 prevents the refrigerant from bypassing via the first bypass pipe 27 and the second bypass pipe 31. I have to.
The refrigerant flows from the load cooler 12 into the compressor 14 through the first refrigerant pipe 24 and is compressed here, and further flows from the compressor 14 into the accumulator 16 through the second refrigerant pipe 26, where The refrigerant dissipates heat, is stored in the heat accumulator 16, and further flows from the heat accumulator 16 into the condenser 18 through the fourth refrigerant pipe 30, where it is condensed or subcooled, and further from the condenser 18 through the sixth refrigerant pipe 50 Flows into the receiver 20, where a fixed amount of refrigerant liquid is received, and the liquid refrigerant flows from the receiver 20 through the fifth refrigerant pipe 40 into the expansion valve 22, where the expansion valve By adjusting the degree of opening of 22, the degree of superheat of the refrigerant is adjusted, and the expansion valve 22 is returned to the load cooler 12 through the third refrigerant pipe 28 to constitute a cooling circuit.
As described above, the refrigerant flows as shown by the arrow in FIG. 10, and the gas state between the load cooler 12 and the heat accumulator 16 through the compressor 14, in particular, the load cooler 12 and the compressor 14 During the low pressure gas state, while the high pressure gas state between the compressor 14 and the heat accumulator 16, while the liquid or wet steam state from the heat accumulator 16 to the load cooler 12 via the expansion valve 22 It is.

Then, as shown in FIG. 11, in the normal operation mode 2 (after the end of heat storage), the second switching valve 34, the third switching valve 36, the expansion valve 22 and the second switching valve 34 are similar to the normal operation mode 1 (FIG. 10). The compressor 14 is operated in a state in which the first switching valve 32, the fourth switching valve 38, the fifth switching valve 44, and the on / off valve 204 are closed.
As in the normal operation mode 1 (FIG. 10), the fourth switching valve 38 of the first bypass pipe 27 is closed, and the check valve 206 of the second bypass pipe 31 allows the first bypass pipe 27 and the second bypass pipe 27 to be closed. The bypass pipe 31 prevents the refrigerant from bypassing.
This operation mode is the normal operation mode as in the operation mode of FIG. 10, but the heat is being stored in FIG. 10, but in the normal operation mode 2 of FIG.

More specifically, the flow path of the refrigerant gas discharged from the compressor 14 may be similar to that during heat storage in FIG.
That is, the refrigerant flows from the load cooler 12 into the compressor 14 through the first refrigerant pipe 24 and is compressed here, and further flows from the compressor 14 into the heat accumulator 16 through the second refrigerant pipe 26, Here, the refrigerant dissipates heat, is stored in the heat accumulator 16, and further flows from the heat accumulator 16 into the condenser 18 via the fourth refrigerant pipe 30, where it is condensed or subcooled, and the condenser 18 to the sixth refrigerant pipe 50 Flows into the receiver 20, where a fixed amount of refrigerant liquid is received, and the liquid refrigerant flows from the receiver 20 into the expansion valve 22 through the fifth refrigerant pipe 40, where By adjusting the degree of opening of the expansion valve 22, the degree of superheat of the refrigerant is adjusted, and the expansion valve 22 is returned to the load cooler 12 through the third refrigerant pipe 28 to form a cooling circuit.
However, since the pressure loss in the heat accumulator 16 inevitably occurs when the discharge refrigerant gas from the compressor 14 flows to the condenser 18 through the heat accumulator 16, in order to eliminate such pressure loss, By opening the sixth switching valve 48 instead of closing the first switching valve 32, the refrigerant gas discharged from the compressor 14 bypasses the heat accumulator 16 via the heat accumulator bypass pipe 46.

Next, as shown in FIG. 12, in the defrost preparation operation mode, the on / off valve 204 is opened, and unlike the first embodiment, the compressor 14 is stopped to stop the freezing operation, but the high temperature in the receiver 20 is high. The heat transfer fluid for defrosting flows into the heat accumulator 16 through the fifth refrigerant pipe 40 and the third bypass pipe 42, whereby the check valve 206 causes the load cooler 12 to pass through the second bypass pipe 31. A loop type thermosyphon is formed from the heat accumulator 16 through the part of the first bypass pipe 27, the bypass pipe 202, the part of the second bypass pipe 31 and the fourth refrigerant pipe 30 to return to the heat accumulator 16 As in the first embodiment, it is possible to promote the melting of the heat storage agent in the heat storage 16 and to suppress the decrease in the saturation temperature of the heat medium for defrosting, thereby reducing It is possible to effectively prevent prolonged strike time.
In this case, particularly immediately after the freezing operation, the refrigerant in the fifth refrigerant pipe 40 between the liquid receiver 20 and the expansion valve 22 is downstream of the compressor 14 and has a relatively high pressure, while the first In a loop type thermosiphon configured by connecting the load cooler 12 and the heat accumulator 16 by the bypass pipe 27 and the second bypass pipe 31, the heat accumulator 16 on the high pressure side and the load cooler 12 on the low pressure side Because the pressure is relatively medium pressure, the differential pressure allows the refrigerant to be naturally supplied from the receiver 20 to the load cooler 12.

Next, as shown in FIG. 13, in the defrost operation mode (initial stage), with the compressor 14 stopped, the open state of the second switching valve 34 is held, and the fourth switching valve 38 and the fifth switching valve 44 is opened while the first switching valve 32, the third switching valve 36, the expansion valve 22 and the on / off valve 204 are closed.
That is, by stopping the cooling circuit in the normal operation mode, the refrigerant can flow from the liquid receiver 20 by enabling the flow of the refrigerant through the first bypass pipe 27, the second bypass pipe 31, and the third bypass pipe 42. While flowing to the heat accumulator 16 via the three bypass pipe 42, a loop type thermosiphon by natural circulation is configured between the heat accumulator 16 and the load cooler 12.
At that time, as in the first embodiment, the start of the defrosting operation is quickened by the defrosting preparation operation, and the prolongation of the defrosting operation is prevented.

In the defrost operation mode, the required amount of refrigerant is an amount sufficient for the thermosiphon to circulate smoothly in the loop type thermosyphon and to obtain the predetermined heat transport necessary for the defrosting of the load cooler 12, It changes according to the capacity | capacitance of the cooler 12, and each piping length of the 1st bypass pipe 27 which is a part of loop type | mold thermosiphon, and the 2nd bypass pipe 31. As shown in FIG.
When the amount of retained refrigerant is sufficient when the compressor 14 is stopped, it is not necessary to feed the heat accumulator 16 from the liquid receiver 20 through the third bypass pipe 42, and the fifth switching valve 44 In the closed state, only the defrosting operation by the loop thermosyphon may be performed.
As described above, the refrigerant flows as shown by the arrow in FIG. 13 and is liquid from the liquid receiver 20 to the heat accumulator 16 via the fifth refrigerant pipe 40 and the third bypass pipe, and from the heat accumulator 16 to the second refrigerant It is a gas state from the load cooler 12 to the heat accumulator 16 via the second bypass pipe 31 from the load cooler 12 to the load cooler 12 through the pipe 26 and the first bypass pipe 27.

Then, as shown in FIG. 14, in the defrost operation mode (normal stage), the second switching valve 34 and the fourth switching valve 38 are opened and held in a state in which the compressor 14 is stopped as in FIG. Meanwhile, the fifth switching valve 44 is closed while the closed state of the first switching valve 32, the third switching valve 36, the expansion valve 22 and the on / off valve 204 is maintained.
More specifically, the refrigerant gas evaporated (thermally absorbed) by the heat storage of the heat storage 16 flows from the second refrigerant pipe 26 through the first bypass pipe 27 to the load cooler 12, where the refrigerant gas is condensed (heat release) As a result, the load cooler 12 is defrosted, the defrosting adhering to the load cooler 12 is removed, and the refrigerant liquid returns from the second bypass pipe 31 to the heat accumulator 16 through the fourth refrigerant pipe 30 and this natural A loop thermosyphon is constructed by repeating circulation.
The oil of the compressor 14 flowing into the load cooler 12 flows out to the first refrigerant pipe 24 at a lower level than the third refrigerant pipe 28, and is fed to the bend portion (not shown) 80. .
When defrosting of the load cooler 12 is completed by the defrosting operation, the normal operation mode 1 may be resumed to resume heat storage in preparation for the next defrosting operation.

The timing of switching between the normal operation mode (FIGS. 10 and 11) and the defrost operation mode (FIGS. 13 and 14) may be switched manually as appropriate according to the state of occurrence of frost in the load cooler 12 Alternatively, when the load on the load cooler 12 is relatively constant and the progress of frost is relatively regular, a timer may be set in advance to switch automatically.
Timing of switching from normal operation mode 1 (FIG. 10) to normal operation mode 2 (FIG. 11), timing of switching from normal operation mode 2 (FIG. 11) to defrost preparation operation mode (FIG. 12), and defrost operation mode The timing of switching from (initial) (FIG. 13) to defrost operation mode (normal) (FIG. 14) may be set automatically by a timer, for example, or the heat transfer tube of load cooler 12 (not shown) The temperature of) may be detected and set according to the detected temperature.

According to the refrigeration apparatus 10 having the above configuration, during the cooling operation, the refrigerant gas evaporated by cooling the load cooler 12 is compressed by the compressor 14 and dissipated in the heat accumulator 16 as a result. The refrigerant gas or the refrigerant liquid is condensed or subcooled in the condenser 18, and the refrigerant liquid is received by the receiver 20, passes through the expansion valve 22, and constitutes a cooling circuit for cooling the load cooler 12 again. , Cool the load cooler 12.

On the other hand, during the defrosting operation of the load cooler 12, the first bypass pipe 27 is transferred from the heat accumulator 16 to the load cooler 12 by utilizing the heat stored in the heat accumulator 16 during the cooling operation of the load cooler 12. Via a second bypass pipe 31 from the load cooler 12 to the heat accumulator 16 via the second bypass pipe 31 to return the refrigerant liquid resulting from the defrosting of the load cooler 12. By constructing a loop type thermosyphon by natural circulation between the heat accumulator 16 and the load cooler 12 on the cold side located above, defrosting in the state where the compressor 14 is stopped can be made possible, and also conventionally It is possible to perform defrosting while achieving energy saving without causing the problem of the small heat transport limit due to the wick system or the thermosiphon system.

        According to the defrost (defrosting) method of the load cooler 12 having the above configuration, the defrosting method of the load cooler 12 located at the uppermost level is performed by the cooling circuit having the compressor 14 for compressing the refrigerant gas. And storing the sensible heat or condensation latent heat of the refrigerant gas discharged from the compressor 14 during the cooling operation of the load cooler 12, and using the heat stored, the load cooler 12 is operated by the thermosyphon method. And the step of storing heat is performed by the heat accumulator 16 installed at a level lower than the load cooler 12, and the thermosyphon method is a loop type defrost between the load cooler 12 and the heat accumulator 16. The circuit may be configured to have a step of bypassing the heat storage unit 16 after the heat storage step is completed during the cooling operation.

Although the embodiments of the present invention have been described in detail, various modifications or changes can be made by those skilled in the art without departing from the scope of the present invention.
For example, in the first embodiment, as long as sufficient heat storage is performed by the heat accumulator 16, only the load cooler 12 requiring defrosting may be separately subjected to the defrosting operation, in which case the defrosting is necessary. When there are a plurality of load coolers 12, heat storage may be performed while performing cooling operation, and so-called chase operation may be performed in which defrost operation is performed.
For example, although the heat storage unit 16 is described in the present embodiment, it is not limited thereto, and a heat storage tank may be used as long as heat storage from the refrigerant is possible, and further, an external heat source may be used without heat storage by the refrigerant. For example, heat may be stored using exhaust heat.
For example, in the first embodiment and the second embodiment, in the case where there are a plurality of load coolers 12, the receiver 20 is installed in the return path 84 for defrosting, but it is not limited thereto. If all the vessels 12 are installed at the same level and the load fluctuation on the load cooler 12 side or the heat accumulator 16 side is not large, natural circulation is stably possible by the loop thermosiphon, so The vessel 20 may be omitted.

It is a block diagram of the freezing apparatus 10 which concerns on 1st Embodiment of this invention. It is a perspective view of the load cooler 12 of the refrigerating apparatus 10 which concerns on 1st Embodiment of this invention. It is the schematic which shows the surroundings of the load cooler 12 of the freezing apparatus 10 which concerns on 1st Embodiment of this invention. The freezing apparatus 10 which concerns on 1st Embodiment of this invention WHEREIN: It is a figure similar to FIG. 1 which shows the normal cooling operation in thermal storage. The freezing apparatus 10 which concerns on 1st Embodiment of this invention WHEREIN: It is a figure similar to FIG. 1 which shows defrost preparatory driving | operation. FIG. 10 is a view similar to FIG. 1 showing a defrosting operation of the load cooler 12A in the refrigeration apparatus 10 according to the first embodiment of the present invention. FIG. 10 is a view similar to FIG. 1 showing a defrosting operation of the load cooler 12B in the refrigeration apparatus 10 according to the first embodiment of the present invention. It is a conceptual graph which shows the temperature change of the heat medium for defrost in the case of the switching from the cooling operation of the freezing apparatus 10 which concerns on 1st Embodiment of this invention to a defrost operation. It is a block diagram of the freezing apparatus 10 which concerns on 2nd Embodiment of this invention. The freezing apparatus 10 which concerns on 2nd Embodiment of this invention WHEREIN: It is a figure similar to FIG. 9 which shows the normal cooling operation in thermal storage. The freezing apparatus 10 which concerns on 2nd Embodiment of this invention WHEREIN: It is a figure similar to FIG. 9 which shows the normal cooling operation after the completion | finish of thermal storage. The freezing apparatus 10 which concerns on 2nd Embodiment of this invention WHEREIN: It is a figure similar to FIG. 9 which shows defrost preparation driving | operation. The freezing apparatus 10 which concerns on 2nd Embodiment of this invention WHEREIN: It is a figure similar to FIG. 9 which shows the initial stage of a defrost operation normally. The freezing apparatus 10 which concerns on 2nd Embodiment of this invention WHEREIN: It is a figure similar to FIG. 9 which shows normal defrost driving | operation.

H Level difference h Level difference 10 Refrigerating equipment 12 Load cooler 14 Compressor 16 Heat storage 17 Receiver 18 Condenser 20 Liquid receiver 22 Expansion valve 24 1st refrigerant piping 26 2nd refrigerant piping 28 3rd refrigerant piping 30 4th refrigerant piping 27 first bypass pipe 31 second bypass pipe 32 first switching valve 34 second switching valve 36 third switching valve 38 fourth switching valve 40 fifth refrigerant pipe 42 third bypass pipe 44 fifth switching valve 46 heat accumulator bypass pipe 48 sixth switching valve 50 sixth refrigerant piping 62 check valve 64 check valve 66 check circuit 70 cooling circuit 72 defrost circuit 74 heat absorbing unit 76 defrost unit 78 heat radiating unit 80 cooling unit 81 condensing unit 82 defrosting path 84 defrost For the return path 86 Inlet side refrigerant branch pipe 88 Outlet side refrigerant branch pipe 90 Inlet side heat medium branch pipe 92 Outlet side heat medium branch pipe 94 Switching DESCRIPTION OF SYMBOLS 100 Ventilation flow path 101 Blower 102 Casing 103 Terminal box 104 Cooling heat transfer pipe 105 Refrigerant header 106 Defrosting heat transfer pipe 107 Defrosting inlet header 109 Defrost outlet header 112 Air cooling refrigerant inflow opening 113 Partition plate 117 Hanging bracket 118 Defrost Heat medium outflow opening 120 Partition plate 122 Refrigerant pipe through holes 123 Defrost pipe through holes 124 Defrosted straight pipe sections 126 Defrosted U-shaped pipe sections 128 Cooling straight pipe sections 130 Cooling U-shaped pipe sections 132 Plate fins 134 Drain pan 135 Heat transfer pipe for defrosting 136 Branch pipe 137 Bottom surface 140 Check valve 141 Divider valve 143 Check valve 145A Cooling water supply pipe 145B Cooling water return pipe 147A Forward path for heat storage 147 Return path for heat storage 149 Level gauge 151 Expansion valve 153却用 return 155 cooling forward path 200 Freezer 202 bypass pipe 204 off valves 206 check valve 220 switching valve

Claims (2)

In a refrigeration system constituting a cooling circuit in which a cooling refrigerant flows by sequentially connecting a load cooler, a compressor, a heat accumulator, a condenser, a receiver, and an expansion valve in this order by a refrigerant pipe,
Furthermore, a defrost circuit is provided which circulates between the load cooler and the heat accumulator,
The cooling circuit and the defrosting circuit are provided separately and independently from a refrigerant circulating in the cooling circuit and a heat medium circulating in the defrosting circuit.
The plurality of load coolers are provided in the same storage unit cooled by the load cooler, and are connected in parallel to the cooling circuit via an inlet-side refrigerant branch pipe and an outlet-side refrigerant branch pipe, and The defrost circuit is connected in parallel via the inlet side heat medium branch pipe and the outlet side heat medium branch pipe,
A switch valve is provided for each of the inlet side refrigerant branch pipe and / or each of the inlet side heat medium branch pipes, and the defrosting heat medium flows inside the defrost circuit, and the heat storage agent is disposed from the heat storage agent in the heat accumulator. A heat absorbing portion for absorbing heat and a defrost portion for radiating heat in the load cooler;
The cooling circuit includes a heat radiating portion which radiates heat to a heat storage agent in the heat accumulator, and a cooling portion which cools a load fluid in the load cooler.
The heat accumulator is installed at a level lower than the load cooler.
The heat transfer medium for defrosting, which is heated by the heat absorbing portion, flows from the heat accumulator to the load cooler, and the heat is dissipated to the defrost unit from the load cooler toward the heat accumulator from the load cooler. And a return path for defrosting through which the heat medium for defrosting flows.
A bypass path is provided connecting the forward path for defrosting and the return path for defrosting,
An on-off valve is provided in the bypass passage,
Accordingly, the load fluid is cooled by the cooling unit through the cooling circuit, and the heat is dissipated to the heat storage agent through the heat dissipation unit, and the heat absorbing unit absorbs heat from the heat storage unit through the defrost circuit, A refrigeration system for defrosting the load cooler through a defrosting unit. Each of the load coolers is provided with a cooling air inflow opening and a cooling air outflow opening, which are disposed to face each other, and a ventilating flow path is provided inside from the cooling air inflow opening to the cooling air outflow opening. With the casing,
A cooling heat transfer pipe which is disposed in the casing so as to cross an air flow along the ventilation flow channel and in which an air cooling refrigerant flows;
And a heat transfer pipe for defrosting, in which a heat transfer medium for defrosting flows, provided independently of the heat transfer pipe for cooling in the casing.
In the heat transfer pipe for cooling, one end opening and the other end opening are respectively connected to an air cooling refrigerant inflow opening and an air cooling refrigerant outflow opening provided in the casing,
In the heat transfer tube for defrosting, one end opening and the other end opening are respectively connected to the heat medium inflow opening for defrosting and the heat medium outflow opening for defrosting provided in the casing, and the heat transfer tube for defrosting is in the casing Wherein the heat transfer tube for cooling is disposed so as to be defrostable in an external heating system,
An inlet-side refrigerant branch pipe and an outlet-side refrigerant branch pipe are connected to the air cooling refrigerant inflow opening and the air cooling refrigerant outflow opening, and the defrosting heat medium inflow opening and the defrosting heat medium outflow opening are connected to each other. The refrigerating apparatus according to claim 1, wherein the inlet-side heat medium branch pipe and the outlet-side heat medium branch pipe are connected.

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