ES2278558T3 - COOLING INSTALLATION. - Google Patents

Abstract

The refrigeration installation has separate refrigerator and freezer circuits each containing a compressor (C1/C2,C3/C4/C5/C with the pressure lines (8,16) leading from the latter combined before a condenser (V) and coupled via a selectively blocked def line (30) with the suction line (10) of the compressor (C3/C4/C5/C6) for the freezer circuit.

Description

Cooling installation

The invention relates to an installation of cooling according to the preamble of claim 1 and a procedure to defrost this installation of refrigeration.

The document US-A-4 474 026 makes patent a cooling system according to the preamble of the claim 1.

The cooling facilities are used for example in supermarkets. There they normally supply many cold consumers such as refrigeration chambers, refrigerator cabinets and freezers. To this end circulate through them a cooling medium or a mixture of cooling medium with one or Various components A refrigeration installation of this type - as is known from DE-PS 39 28 430 - presents a blender, in which the cooling medium condenses under pressure by indirect heat exchange, with preference for outside air.

The liquid cooling medium is fed from the blender to a collecting tank. Inside a cooling installation must always exist both medium refrigerant that, even with a maximum need for cold, can fill evaporators of all cold consumers. Without However, because in the case of a cold need, the insulated evaporators are only partially filled or even completely empty, it is necessary that the cooling medium leftover is collected during these periods of time in the deposit collector planned for it.

However, in principle it can also be thought in dispensing with a collecting tank of this type.

The medium is fed from the collecting tank Refrigerant to cold consumers.

A cold consumer has been preconnected a expansion device, preferably an expansion valve in which the cooling medium circulating in the cold consumer or the consumer's evaporator or evaporators of cold. The cooling medium thus expanded vaporizes in the consumer evaporators of cooling medium and refrigerates this way the refrigerating cabinets and cold rooms corresponding.

The vaporized cooling medium in this way is then fed through a suction duct to a compression unit These compression units can be configured with one or several stages. Compression stages isolated normally present several compressors connected in parallel. These compress the cooling medium and transport them to in turn, through an ascending duct, to the blender already aforementioned. While the compression unit is normally arranged for example in a machine room arranged in the basement of a supermarket, the blender is on the Roof of the supermarket.

If a market is available within a market so-called normal cooling and low cooling points temperature, they are supplied by means of medium circuits separate refrigerant; this means therefore that it is available at least twice from a refrigeration installation, such as the described in DE-PS 39 28 430.

Investment and operating costs, as well as the complexity of installation, necessary to cool the points normal cooling and low temperature cooling of a market, are however considerable.

The mission of the present invention consists in indicate a refrigeration installation of the generic class, which does necessary investment and exploitation costs as well as a minor installation complexity.

This mission is solved according to the invention. by claims 1 and 14.

The refrigeration system according to the invention as well as additional configurations thereof are will explain in more detail based on the form of execution represented in figures 1 and 2.

The refrigeration installation represented in the Figure 1 presents only a blender or condenser V. To this one you can be connected - according to an advantageous configuration of the invention - a collecting tank S1. Liquid cooling medium it is fed from the blender V, through the conduit 1, to the collecting tank S1. From this the cooling medium arrives, to through liquid conduits 2, 3 and 4, to consumers from normal cooling circuit to low cooling temperature. Here consumers V1 and V2 represented in the figure 1 represent any number of consumers of the normal cooling circuit while consumers V3 and V4 represented in figure 1 represent any number of consumers of the low cooling circuit temperature.

Each cold consumer V1 to V4 is pre-connected an expansion valve a to d, in which the  cooling medium circulating in the cold consumer or the or cold consumer evaporators. The cooling medium as well expanded vaporizes in the evaporators of consumers of cooling medium V1 to V4 and thus refrigerates the cabinets refrigerators and cold rooms of the circuit Normal cooling and low temperature cooling.

The vaporized cooling medium in the Cold consumers V1 and V2 of the normal cooling circuit it is fed, through a suction duct 5, to the unit normal cooling circuit compression. This has been pre-connected - subject to an additional advantageous configuration of the refrigeration system according to the invention - a tank suction manifold S2. Normally the compression unit of the Normal cooling circuit is configured with only one stage and presents several compressors, preferably connected in parallel; for greater clarity they have been represented in the figure only two compressors C1 and C2 connected in parallel. These aspirate cooling medium, through conduits 6 and 7, from the suction manifold tank S2 and transport the medium compressed refrigerant, through pressure line 8, up to a heater E. After running the heater E, the medium refrigerant is fed again, through conduit 9, to the condenser or blender V already described.

For clarity it has not been represented in Figure 1 low temperature refrigeration or refrigeration additional required cooling medium in the liquid conduit 4, which can be done for example in a heat exchange indirect with the cooling medium transported in the duct 10.

It is advantageous that - according to a configuration additional advantage of the refrigeration system according to the invention - the device for cooling at low temperature the cooling medium in the liquid conduit 4 of the circuit low temperature cooling is spatially arranged as close as possible to the cold consumers V3 and V4 of the circuit Low temperature cooling. Through this configuration  of the refrigeration system according to the invention can minimize power loss due to heat absorption from the environment.

The cooling medium fed to the V3 and V4 consumers of the low cooling circuit temperature, through the liquid conduit 4, is fed to the compression unit of the low cooling circuit temperature through the suction duct 10. Turn to the compression unit of the low cooling circuit temperature - subject to an additional advantageous configuration of the refrigeration system according to the invention - may be preconnected a low pressure suction manifold tank S3

The circuit compression unit low temperature cooling is set preferably to the least with two stages, where in turn, for clarity, each compression stage has been represented by two C3 and C5 compressors as well as C4 and C6 connected in parallel. The C3 and C5 compressors of the first compression stage suck medium gaseous refrigerant through ducts 11 and 12, from the S3 low pressure suction manifold tank, and transport the compressed cooling medium at an intermediate pressure, through from duct 13, to the pressure suction manifold tank intermediate S4. From this the compressors C4 and C6 of the second compression stage aspirate cooling medium, through the conduits 14 and 15, and transport the compressed cooling medium to then, through the pressure line 16, also up to in front of heater E already mentioned in the duct 9.

Naturally, the compression unit of the low temperature cooling circuit can - on the contrary that the representation in figure 1 - be configured with three or more stages; in this case they could be preconnected to the stages of compression isolated in each case collecting tanks of separate aspiration. It wants to be noted that, naturally, It is also possible to dispense with this type of collecting tanks aspiration.

The cooling system according to the invention presents relative to known solutions about investment and operating costs as well as a complexity of minor installation. It also makes it possible - as will be discussed more forward - other ways of proceeding and constructive configurations, that cannot materialize or only very hard with current solutions.

The cooling system or the evaporators arranged in cold consumers have to thaw at regular intervals, as the aging or evaporator freezes lead to a reduction in degree of efficiency of evaporators.

One possibility of defrosting is the call electric defrosting In it, defrost the evaporators by means of heaters arranged on and / or in the same. This way of proceeding, however, leads to consumption excessive unwanted electrical power.

As an alternative to electric defrosting described is called defrosting of gas under pressure. In it is laid between the gas chamber of the collecting tank, postconnected to the blender, and each evaporator or each group of evaporators gas pipelines under pressure and through them feeds gaseous cooling medium, which has a temperature between 35ºC and 45ºC, from the collecting tank to the evaporators or groups of evaporators. The complexity of installation for this pressure defrosting of gas is however relatively high, since for each evaporator or each group of evaporators it is It is necessary to provide a separate gas pressure line.

Especially in the case of refrigerated cabinets the complexity of work required is very high, since the necessary ventilation stations should normally be arranged in the bottom side of the refrigerator cabinet, and these are hardly accessible precisely in the case of maintenance.

Compared to electric defrosting this defrosting of pressurized gas requires, as regards the network of pipes, additional complexity. Apart from the advantage of a operating cost reduction should be considered an advantage essential in defrosting gas under pressure the lowest load Thermal products. The product temperature during and just after defrosting acquires, however, a increasing importance, such that the defrosting of gas pressure could be the only possibility in the future satisfy the requirements of the legislator in relation to the requirement "product temperature".

In the case of the cooling installation according to the invention the pressure ducts 8 and 16 of the C1 / C2 and C3 / C4 / C5 / C6 compression units through a defrost conduit 30 that is configured, with preference, so that it can be locked for example by a valve, to the suction duct 10 of the compression unit C3 / C4 / C5 / C6 of the low temperature cooling circuit.

During the defrosting phase it is interrupted then the cooling medium feed from the compression unit C1 / C2 of the normal cooling circuit until the blender V, the compression unit is disconnected C3 / C4 / C5 / C6 of the low temperature cooling circuit and it feeds the heated cooling medium, through the duct open defrost 30 to suction duct 10 and, through thereof, to the cold consumers V3 and V4 of the circuit low temperature cooling The circulation route of cooling medium during the defrosting phase is represented by the large framed arrows.

The cooling medium that circulates through Cold consumers V3 and V4 of the cooling circuit to low temperature or its evaporators are fed, through the ducts 3 and 4, to the cold consumers V1 and V2 of the circuit normal cooling and then through the duct suction 5 back to the C1 / C2 circuit compression unit Normal cooling During defrosting works the C1 / C2 compression unit, thus, as a heat pump. In how much the evaporators of the cold consumers V3 and V4 of the low temperature cooling circuit are defrosted by complete, the defrost line 30 is closed again by closing the valve e, the power unit is disconnected C3 / C4 / C5 / C6 compression of the low cooling circuit temperature and switch to cooling operation. The middle refrigerant then circulates again through the pressure ducts 8 and 16 as well as the entire pressure duct 9, from compression units C1 / C2 and C3 / C4 / C5 / C6 to the blender V.

At the beginning of the defrosting phase is convenient to circulate hot coolant medium from the collecting tank S1, through the liquid ducts 2 and 4, to the evaporators of the cold consumers V3 and V4 of the low temperature cooling circuit In the evaporators a defrost in each case is dammed by this means liquid refrigerant, which already causes heating of the evaporator to defrost. As for the cooling medium, powered by the C1 / C2 circuit compression unit normal cooling through defrosting duct 30 to the evaporators of the cold consumers V3 and V4, circulates up to the evaporators the embalmed cooling medium is ejected previously in them. Once the pressure compensation between the V liquor or the reservoir S1 manifold and pressure ducts, it is only transported more cooling medium by means of compression unit C1 / C2, a through defrosting duct 30 and duct suction 10, to the evaporators of cold consumers V3 and V4.

Because in different refrigerating cabinets evaporators of different sizes are arranged and / or the evaporators have different degrees of icing, these do not simultaneously reach the final defrosting temperature necessary for example 15 ° C.

An additional advantageous configuration of the cooling system according to the invention is characterized by that because at least one of the consumers of cold V3 and V4 of the cooling circuit at low temperature or at the evaporators of these cold consumers is preconnected a directly controlled magnetic valve, which is arranged in parallel to the corresponding expansion valve of the consumer of cold.

This configuration of the cold installation in accordance with the invention is explained in more detail below. based on figure 2, which shows the direct region of the cold consumer V3 shown in figure 1; It's about the region surrounded by a dashed line in figure 1.

This shows the consumer V3 or its evaporator, the liquid conduit 4 and the suction conduit 10 shown in figure 1 as well as the expansion valve c associated with the evaporator of the consumer V3, through which injected in cooling operation the cooling medium in the evaporator In cooling operation circulates from this coolant mode from liquid conduit 4, through the conduit 40, to the expansion valve c and from it, through from conduit 42, to the evaporator of the cold consumer V3.

In accordance with the invention, it is intended to then, parallel to the expansion valve c in a conduit bypass 41, a magnetic valve c 'directly controlled. During the defrosting process, cooling medium circulates at through defrosting duct 30, not shown in the Figure 2, as well as the suction duct 10 to the V3 cold consumer evaporator and then through conduits 42 and 41, to liquid conduit 4. If reaches the final temperature of one of the evaporators preset defrosting - what you can register for example by means of a corresponding freezing sensor -, it closes the magnetic valve c '.

The magnetic valve c 'directly controlled acts, in the case of a coil without current, as a valve retention with an opening pressure of approx. 1.5 bars that It depends on the valve. By closing a magnetic valve at the corresponding final defrosting temperature it moves defrosting power to those evaporators that have not yet They have reached the final defrosting temperature. Yet already defrosted evaporator does not feed therefore unnecessarily medium refrigerant, but only to those evaporators that have not yet completely thawed. These in this way they reach the final temperature of default defrosting.

As soon as all evaporators have reached its end of defrosting and, thus, its magnetic valves are closed, it is created between the evaporators and the duct liquid 4 a pressure difference. As for this difference of pressure is greater than 1.5 bar, through the magnetic valves reverse circulation occurs and the liquid medium refrigerant located in the evaporators is pressed until the liquid conduit 4.

Once the defrosting phase is over the evaporators are aspirated simultaneously through the compressors of the normal refrigeration circuit and of the low temperature cooling As for the pressure of evaporator drops below the temperature of the TEV sensor (Thermostatic Expansion Valve), is automatically injected from new cooling medium in the evaporator. The cooling of the evaporators of the low temperature cooling circuit will Produces in about 5 minutes. For this, in addition to the compressor power of the refrigeration circuit at low temperature, of the compressor power of the circuit normal cooling, since the cooling points or cold consumers of the normal cooling circuit are connected to forced cooling, during defrosting of cold consumers evaporators V3 and V4 circuit low temperature cooling, and through this reach temperatures below the nominal value. For the entire region of low temperature cooling can therefore be achieved by defrosting period clearly shorter than the electric defrosting

The materialization of the defrosting procedure described does not require in the case of the refrigeration installation according to the invention, in comparison with a refrigeration installation in which an electric defrosting is carried out, an additional complexity in pipes and fittings. Because defrosting of the evaporators of the cold consumers V3 and V4 of the low temperature cooling circuit it is not necessary to connect any power - as is the case for example in the case of an electric defrost -,
in the energy balance it is only necessary to take into account the cooling after the defrosting phase. The defrosting power itself is pure heat pump operation from the normal cooling interconnection network or from the C1 / C2 compression unit.

An additional advantage is that pipe insulations in poorly ventilated soil cabales and / or below Refrigerator cabinets are no longer soaked, as they get hot necessarily every 48 hours during the defrosting process.

Also the product is exposed to a minor temperature load, since now it is only necessary to defrost three times a week - for example on Tuesdays, Thursdays and Saturdays. In the case of separate cooling media circuits and a defrosting of cold gas this is not possible, since after 48 hours of cooling operation in the circuit low temperature cooling would not have power of defrosting for the first defrosting group.

During the night or closing periods commercial takes the cold installation to a call energy saving operation. Under the term operation Energy saving conditions must be understood here operation in which refrigerated cabinets have been lowered or placed on the night roller blinds, have the lights off, the doors of the cameras no longer open refrigerators and thus no flow of goods occurs - that is, the extraction or introduction of goods from or in the cold cabinets or cold rooms.

The need for cold during these periods is often so reduced that in the compression unit of the normal cooling circuit a circuit called Pump-Down Under the term "circuit Pump-Down "the aspiration of the evaporators of cold consumers. This has as consequence that, on the one hand, the cooling points with a reduced cold need no longer reach temperatures nominal and, on the other hand, the frequency of connections of Normal refrigeration circuit compressors becomes elevated from unnecessary and unwanted way, since the frequency of connections Increased these compressors leads to reduced life Useful.

An additional advantageous configuration of the cold installation according to the invention is characterized because the low temperature cooling circuit has a C3 / C4 / C5 / C6 compression unit with at least two stages and side suction of the normal cooling circuit is in union effective with one side or one of the intermediate pressure sides of the low temperature cooling circuit While at compression stages C1 and C2 of the normal cooling circuit and at least one of the compression stages C4 and C6 of the circuit low temperature cooling, where it is not the first compression stage C3 and C5, deposits are preconnected suction manifolds S2 and S4, these are preferably mutually in effective union.

This configuration of the installation of refrigeration according to the invention makes it possible next other advantageous operating modes, such as those with known refrigeration installations cannot materialize or only with a corresponding complexity.

An effective union between the suction side of the normal cooling circuit and the one from the intermediate pressure sides of the cooling circuit to low temperature or between the suction tank of the normal cooling circuit and the one or one of the tanks intermediate pressure suction manifolds of the circuit low temperature cooling, according to a configuration advantageous of the refrigeration system according to the invention, through at least one junction conduit 20.

It is imaginable - according to an alternative configuration of the refrigeration system according to the invention - that the operation of the suction collector tank of the normal refrigeration circuit and of one or one of the intermediate pressure suction collector tanks of the refrigeration circuit at low temperature it materializes in a common suction collection tank. This embodiment of the refrigeration system according to the invention has not been shown in the figure
one.

Through this configuration of the cooling system according to the invention it is possible that,  during night operation and / or commercial closing, it disconnect compressors from the cooling circuit normal.

Because in the case of a unit of compression with two stages in the low cooling circuit temperature the intermediate pressure depending on the temperature of liquefaction during energy saving operation is always lower than the vaporization temperature of the circuit normal cooling, the necessary lower load of the region of Normal cooling is assumed by the second compression stage - the so-called high pressure compression stage - of the circuit low temperature cooling This has as a consequence that All cold consumers of the normal cooling circuit with reduced need for cold temperatures can reach Nominals required, even if all circuit compressors Normal cooling are disconnected. This way you can dispense with a compressor connection of the circuit normal cooling; compressor connection frequency of the normal cooling circuit is reduced with this quite a bit; which increases the life expectancy of these compressors. Because during the energy saving operation the Normal refrigeration circuit compressors work is assumed by the refrigeration circuit compressors at low temperature, improves its full performance.

A further configuration of the cooling system according to the invention is characterized in that an oil compensation line 21 is provided, which joins the suction manifold tank S2 of the normal cooling circuit and the intermediate pressure suction manifold tank S4 of the circuit low cooling
temperature.

The cooling system according to the invention thus offers a multitude of advantages over to known refrigeration facilities, especially in regarding the defrosting of the evaporators and the operation Energy saving This makes it possible with less complexity of installation and, as a result, with lower costs investment. Because both energy consumption and complexity of maintenance are reduced, also lower the costs of functioning. It is also possible with the procedure of defrosting described compliance with legal regulations future.

It is to be noted that the invention could be realized, not only in the case of a cooling installation of the low temperature cooling circuit with a compression unit with at least two stages - as shown in Figure 1 -,
but also with a one stage compression unit.

Claims (18)

1. Refrigeration installation to cool at least one cold consumer through a normal cooling circuit and to cool more than one cold consumer through a low temperature cooling circuit, where each circuit has a compression unit, only one blender is provided and the pressure ducts of the compression units meet in front of the blender, and where the cold consumers of the low temperature cooling circuit are connected, in each case at junction points, to a duct of common suction (10) attached to the compression unit (C3 / C4 / C5 / C6) of the low temperature cooling circuit, characterized in that the pressure ducts (8, 16) of the compression units (C1 / C2 / C3 / C4 / C5 / C6) are connected through a defrost line (30), which is connected between the compression unit (C3 / C4 / C5 / C6) of the low temperature cooling circuit and the junction point located closer to it, which leads a cold consumer (V3), to the suction duct (10) of the compression unit (C3 / C4 / C5 / C6) of the low temperature cooling circuit. 2. Refrigeration installation according to claim 1, characterized in that the defrosting duct (30) is configured so that it can be blocked. 3. Refrigeration installation according to claim 1 or 2, characterized in that only one collecting tank is connected to the blender (V)
(S1). 4. Cooling system according to one of the preceding claims, characterized in that between the blender (V) or the collection tank (S1) and the liquid lines (3, 4) of the normal cooling circuit and the low temperature cooling circuit only one liquid conduit (2) is arranged. 5. Refrigeration installation according to one of the preceding claims, characterized in that the device for cooling at low temperature the cooling medium in the liquid conduit (4) of the low temperature cooling circuit is arranged, spatially, as close as possible to the Cold consumers (V3, V4) of the low temperature cooling circuit. 6. Refrigeration installation according to one of the preceding claims, characterized in that at least one of the cold consumers (V3, V4) of the low temperature refrigeration circuit is directly connected to a directly controlled magnetic valve (c '), which is arranged in parallel to the corresponding expansion valve (c) of the cold consumers (V3, V4). 7. Refrigeration installation according to one of the preceding claims, characterized in that a heater (E) is pre-connected to the blender (V). 8. Cooling system according to claim 7, characterized in that the pressure ducts (8, 16) of the compression units (C1 / C2, C3 / C4 / C5 / C6) meet in front of the heater (E). 9. Cooling system according to one of the preceding claims, characterized in that the low temperature cooling circuit has a compression unit (C3 / C4 / C5 / C6) with at least two stages and the suction side of the normal cooling circuit it is in effective connection with the side or one of the intermediate pressure sides of the low temperature cooling circuit. 10. Refrigeration installation according to one of the preceding claims, characterized in that at least one compression stage (C1 / C2) of the normal refrigeration circuit and one compression stage (C4 / C6) of the low temperature refrigeration circuit, in where it is not the first compression stage (C3 / C5), suction manifold tanks (S2, S4) are preconnected and these are in effective connection. 11. Refrigeration installation according to claim 9 or 10, characterized in that the effective connection is realized through at least one connection duct (20). 12. Refrigeration installation according to claim 11, characterized in that an oil compensation duct (21) is provided, which joins the suction manifold tank (S2) of the normal refrigeration circuit and the one or one of the suction manifold reservoirs of intermediate pressure (S4) of the low temperature cooling circuit (21). 13. Refrigeration installation according to claim 10, characterized in that the operation of the suction manifold tank (S2) of the normal refrigeration circuit and the intermediate pressure suction manifold tank (S4) of the low temperature refrigeration circuit is embodied in a suction collector tank. 14. Procedure to defrost a cooling system according to one of the claims 1 to 13, where heated coolant medium is fed from of the compression unit (C1 / C2) of the cooling circuit normal, through the defrosting duct (30), to the duct suction (10) of the compression unit (C3 / C4 / C5 / C6) of the low temperature cooling circuit and, through it, to the cold consumers (V3, V4) of the cooling circuit to low temperature. 15. Method according to claim 14, in where during the defrosting process the Coolant feed from the compression unit (C1 / C2) from the normal refrigeration circuit to the blender, and the compression unit (C3 / C4 / C5 / C6) is disconnected from the circuit low temperature cooling 16. Method according to claim 14 or 15, where the cooling medium fed to consumers of cold (V3, V4) of the low temperature cooling circuit at then the cold consumers (V1, V2) of the normal cooling circuit and then transported to the compression unit (C1, C2) of the circuit normal cooling, where the compression unit (C1, C2) of the Normal cooling circuit works as a heat pump. 17. Procedure according to one of the claims 14 to 16, wherein at least one of the Cold consumers (V3, V4) of the low cooling circuit temperature or to the evaporators of at least one of these cold consumers a magnetic valve (C ') is preconnected directly controlled, which is arranged in parallel to the corresponding expansion valve of the cold consumer, and in where the cooling medium circulates during the process of defrosting from the suction duct (10) to the evaporator of at least one cold consumer (V3, V4) and through the magnetic valve (c ') open. 18. Method according to claim 17, in where the magnetic valve (c ') closes if in the evaporator corresponding of at least one cold consumer (V3, V4) is reaches a final preset defrost temperature.