EP3311083B1 - Refrigerated display case - Google Patents

Description

The invention relates to a refrigerated shelf according to claim 1 with at least one unit made up of several wall groups, namely a floor group, a rear wall group and a roof group, which delimit a cooling space at the bottom, back and top, and with a cooling device having a refrigerant circuit, which has at least one evaporator as components , a condenser and an electrical control device.

A cooling shelf of this type is in the JP 2004 273271 A specified. This cooling shelf, which can also be operated as a warming cabinet, contains propane as a refrigerant in a refrigerant circuit. To prevent propane escaping from a leak from igniting, the coiled tube of a heating component is provided with a large number of cooling fins arranged in a row.

Another cooling shelf goes out of the DE 10 2012 107 713 A1 out. It is particularly suitable for use in closed rooms and is characterized by a stable structure and a simple variation of the cooling shelf size, which also allows larger quantities of refrigerated goods to be cooled.

In the EP 0 940 641 A2 a device is shown with a cooling device in which propane is used as a refrigerant, for example. B. is used with an amount of 250 g and in a comparative example an amount of 400 g of propane is also mentioned, with a cooling Machine oil with low solubility relative to propane is used, which means the amount of propane can be reduced.

Another refrigeration shelf operated with a refrigerant formed by hydrocarbons is in the JP H08 200944 A shown. A compressor and a condenser are housed in a machine room, which is arranged in a lower shelf area.

Nowadays, refrigeration cabinets with higher cooling output (approximately > 2 kW) are still mostly operated with conventional, usually fluorinated refrigerants, especially when used in closed rooms. One reason is the properties of alternative, natural refrigerants, such as carbon dioxide or hydrocarbons, due to which natural refrigerants cannot easily be used in existing systems.

For example, hydrocarbons such as propane or butane, which are natural refrigerants, are subject to restrictive regulations (e.g. IEC 600335-2-89) due to their ignitability, according to which their filling quantities are limited to up to 150 g per refrigerant circuit in conventional cooling systems. However, such quantities are not sufficient for higher cooling capacities. For the required quantities above 150 g, the safety requirements increase considerably, especially in closed rooms, so that considerable effort is required to meet these requirements.

Due to the high level of effort involved, hydrocarbons are usually used in refrigeration cabinets for indoor use, if at all, in refrigerant circuits with filling quantities of up to a maximum of 150 g, so that as a rule only smaller performance classes are served with hydrocarbons (cf. e.g. Climate Change 17/2014, Dr . Michael Kauffeld, study "Decentralized plug-in cooling devices", Federal Environment Agency 2014, table 3).

In order to be able to use hydrocarbons in higher performance classes, relatively complex systems are used, such as the use of several cooling circuits, each with a maximum capacity of 150 g of refrigerant in order to meet safety requirements. Each circuit must be equipped with separate components such as a condenser or compressor. Such a system is, for example, in the (still unpublished at the time of registration) DE 10 2015 106 620 stated by the applicant.

In the DE 20 2007 015 832 U1 A sales piece of furniture with an electrically powered roller blind is specified. The use of a natural refrigerant, especially with a coolant quantity of more than 150 g, is not mentioned. Because of the opposing problems, natural refrigerants have proven themselves in higher performance classes despite being suitable, for example. B. not accepted as a refrigerant in terms of global warming potential, availability and thermodynamic properties. Rather, fluorinated refrigerants are still used, which can be disadvantageous from an environmental point of view, especially with regard to global warming potential.

The invention is based on the object of providing a refrigerated shelf of the type mentioned at the outset, which is climate-friendly, efficient and can be operated safely.

The following must be added: 0.8 bar is 80,000 Pa; 2 bar is 200,000 Pa; 20 bar is 2,000,000 Pa and 30 bar is 3,000,000 Pa.

This task is solved with the features of claim 1.

The present invention is disclosed in independent claim 1. Further embodiments are disclosed in the dependent claims.

As was found in the inventors' studies, higher cooling outputs of, for example, more than 2 kW can be achieved using propane as a natural refrigerant with its positive properties in terms of global warming potential, availability and thermodynamic properties cover efficiently. In particular, larger refrigerated shelves, which can consist of several units or shelf modules, can be operated in this way with only one refrigerant circuit carrying propane. For example, a refrigerated shelf with a length of more than 2 m, in particular a so-called multi-axis refrigerated shelf made up of several (e.g. two or three) shelf modules (e.g. each 1.25 m long), can be operated with only one refrigerant circuit , whereby a high cooling performance is maintained even with longer refrigerated shelves, as the inventors' studies have shown. If there is no need to use several refrigerant circuits in a refrigerated shelf of this length, this has a positive effect on reducing complexity, since, among other things, the number of components present in the cooling device, the total length of the refrigerant line and the assembly effort can be reduced. This in turn has an advantageous effect on the installation and maintenance effort as well as on the operating costs, e.g. B. in comparison to using several refrigerant circuits with filling quantities below 150 g.

In connection with the structure mentioned, a filling quantity of propane between 300 g and 1500 g is present in the refrigerant circuit to achieve the required cooling capacity. Filling quantities above 1500 g, for which more stringent regulations apply anyway, are not required.

The compressor and the condenser are spaced apart, arranged in different wall groups. The evaporator is arranged in the rear wall group, since here, for example, a large area is available for heat exchange with the cooling space, so that efficient cooling of the refrigerated goods can be achieved. Furthermore, the rear wall group can offer a favorable installation space. The spaced arrangement of the compressor and condenser, which is arranged on or in the roof group, allows these individual components to be placed favorably, for example in terms of function, accessibility, use of installation space and installation measures. In connection with propane as a refrigerant results There is also the advantage that heat pockets can be avoided due to the distributed arrangement of the components, since there is no accumulation of heat due to several heat-generating elements in a small space. This measure helps to avoid high temperatures, which could be critical with regard to the ignition point of the propane.

A filling quantity between 500 g and 900 g, in particular between 650 g and 800 g, has proven to be particularly advantageous, as this also allows common e.g. B. two- or three-axis refrigerated shelf sizes can be operated with a cooling device that only has one refrigerant circuit. Surprisingly, it has been found that a certain filling quantity is advantageous, for example. B. can be used for a single-axis and also multi-axis cooling shelf, so that with a cooling device designed for this purpose with relatively minor modifications, such as. B. Evaporator length, refrigerated shelves of different lengths can be operated with the required cooling capacity. Since largely the same components can be used for different shelf lengths, this can have an advantageous effect on storage and installation measures. However, to optimize refrigerated shelves of different lengths despite similar filling quantities in the circuit, it can also be advantageous to install different components.

Advantages in terms of operation and cooling effect result from the fact that the refrigerant circuit has a low-pressure area with an operating pressure between 0.8 and 2.0 bar and a high-pressure area with an operating pressure between 20 and 30 bar. The low-pressure region is located downstream of an expansion element and in particular includes the evaporator. The high pressure area extends from the compressor to upstream of the expansion element and includes the condenser.

The compressor is arranged in the lower region of the rear wall group below the evaporator. At least one fan to support the cold air flow is advantageously arranged above the evaporator in the rear wall group.

It is helpful to meet the increased safety requirements associated with propane if the fan or fans have motor overtemperature protection. In this way, high motor temperatures can be avoided, which could occur, for example, if the fan motor is defective. Advantageously, the blades of the fan can also be made of a special material that prevents sparks, in particular plastic, or can be coated accordingly. The use of valves, e.g. B. Solenoid valves, which are particularly protected against sparks and/or overheating, are advantageous in connection with propane. A further advantageous measure in this regard is to dispense with a commonly used brine valve, as is used in refrigerated shelves according to the prior art, ie without propane, in a secondary coolant circuit and which is arranged, for example, on or in the roof group. In this way, complex protective measures in connection with this valve can be dispensed with.

The control device is preferably arranged on, in particular in or on, the roof group, where it is not only visually inconspicuous but can also be placed in an easily accessible and protected manner. A contribution to safe operation in connection with propane is that the control device is surrounded by a housing, for example a metal housing, in a shielding manner, which also offers protection against environmental influences such as moisture influences, in particular splash water, and damaging influences on electrical components. Such a housing additionally shields electrical components in the control device from the refrigerant circuit carrying propane.

A further safety-related advantage arises if the components of the cooling device arranged in the refrigerant circuit have a maximum surface temperature of less than 300 ° C, preferably less than 160 ° C, during operation. This temperature is sufficiently below the ignition temperature of propane of 470 °C to not cause ignition even in the unlikely event of propane escaping from the refrigerant circuit and the formation of an ignitable mixture.

The compressor is preferably designed as a fully hermetic and suction gas-cooled compressor, in particular as a scroll compressor. The fully hermetic seal prevents propane from escaping into the environment. The cooling prevents the compressor from overheating, which is beneficial both in terms of safety and in terms of the service life of the compressor. If the compressor is also located in the lowest area of the refrigerant circuit with respect to the geodetic height, this promotes the return transport of any oil that may be in the refrigerant circuit and can thus avoid places in the circuit where oil accumulates.

For safe operation of the refrigerated shelf with propane, it is also advantageous if the electrical system used on the refrigerated shelf is at least partially protected against spark shock. The electrical system of the refrigerated shelf includes, for example, the power supply of the individual components of the cooling device, but also the lighting, the roller blind motor, etc., as well as connections for controlling and/or regulating components, possibly data connections and possibly other electrical equipment. Areas in which sparks cannot be ruled out can, for example, be enclosed.

The measures are advantageous in that at least one safety contactor is arranged in a main circuit of the refrigerated shelf, which, for example, allows monitoring of the contacts in the contactor. Preferably, electrical components are also at least partially provided with a coating that suppresses sparks. The components can be electrical components such as. B. capacitors and the like, but z. B. also surfaces of components in the cooling device or other mechanical components. It also helps to suppress sparks if the conductor track spacing of the high-voltage lines is at least 3 mm, e.g. B. between 3 and 5 mm, or at least 5 mm. In addition, in a preferred variant, plug connections that prevent sparks can be used. The use of spark-protected relays and power supplies is also an advantage, e.g. B. in the area of the control device.

In an advantageous variant of the refrigerated shelf, the evaporator comprises a heat transfer device with aluminum fins and/or copper tubes, which have an inner diameter between 8 mm and 20 mm, preferably between 10 mm and 15 mm (e.g. 12 mm) and/or a maximum Have a volume between 3 l and 7 l (e.g. 4 l or 6 l). With such a heat exchanger, e.g. B. due to the used, Good heat-conducting materials and an easy-to-implement flat design, the cooling of the cold room is possible efficiently in conjunction with propane as a refrigerant. Other heat transfer devices that are suitable for use with propane would also be conceivable.

Great flexibility in terms of installation with high efficiency can be achieved if the condenser comprises a (for example soldered) plate heat exchanger with the countercurrent principle, on the warm side of which the flow of propane is up to 100 kg/h, preferably up to 80 kg/h and on The cold side of which uses a glycol/water mixture as a coolant in a secondary circuit. A mixture of water with 30-50 vol% (e.g. 38 vol%) propylene glycol has proven to be particularly suitable, but other mixtures can also be used. The use of a glycol/water mixture, also known as brine in connection with cooling devices, prevents ice formation in the water. The coolant absorbs the enthalpy removed from the cooling space by the propane and thus removes it from the refrigerant circuit. Air cooling of the refrigerant circuit would also be conceivable, although air has poorer thermal conductivity than a water mixture. In addition, the use of a glycol/water mixture in a secondary circuit allows several cooling units with their heat exchangers to be connected to the secondary circuit and the coolant in turn to be fed to a central recooling device where it is cooled down. Such a recooling device can be arranged at a distance from the refrigerated shelf via a return line, in particular in a separate room, which brings advantages in terms of installation space and accessibility. Particularly when used with propane, there is also the additional advantage that special safety measures, such as those described above, can be dispensed with in the recooling device due to its distance from the propane-carrying refrigerant circuit.

A stable basic structure of the refrigerated shelf can be obtained in that the refrigerated shelf comprises at least two stackable shelf modules, which are constructed from identical module frames with side frames having frame profiles, which carry the floor group, the rear wall group and the roof group with respective cladding parts and that the shelf modules with the in The rear wall group is provided with a common evaporator which extends over several or all shelf modules. Refrigerated shelves of different lengths can be easily produced using a varying number of shelf modules arranged in a row. A refrigerated shelf made up of several shelf modules, in which a cooling device with a refrigerant circuit is used, can in turn be integrated as a module into a refrigerated shelf arrangement made up of several refrigerated shelves. In this way, a high degree of flexibility can be achieved with regard to the structure. For a simple structure, the side frames preferably have a C-shape when viewed from the side.

Energy-efficient operation of the refrigerated shelf can be achieved by mounting a front roller blind driven by a roller blind motor in the front section of the roof group. In this way, the cooling space can be closed or covered at times when it does not need to be accessible, so that the cooling capacity can be reduced to maintain the product cooling temperature. The roller blind motor, which is already advantageously positioned in the entire structure, also has a structure that prevents sparks and/or it is housed in a shielding encapsulation. The structure that prevents sparks can be achieved, for example, as mentioned above, by plug connections that prevent sparks, appropriate coatings or other measures. The encapsulation is advantageously gas-tight, so that in the event of a propane leak from the refrigeration circuit, no ignitable mixture gets into the housing. This could also be the case In the event of a spark on the roller blind motor or in the event of overheating due to a defect, do not ignite any ignitable mixture. The roller blind motor can also advantageously be provided with motor overtemperature protection, so that the motor no longer operates if a certain temperature is exceeded.

Fig. 1

Ein Kühlregal mit drei aneinandergereihten Regalmodulen (in noch nicht vollständig montiertem Zustand) in perspektivischer Ansicht von vorn, seitlich,

Fig. 2

eine schematische Ansicht zweier Kühlregale aus zwei Regalmodulen bzw. drei Regalmodulen mit schematisch dargestellten Komponenten einer Kühleinrichtung mit einem Anschluss an eine zentrale Rückkühleinrichtung,

Fig. 3

eine perspektivische Ansicht eines Kühlregals von schräg seitlich vorn in seitlich offener Darstellung und

Fig. 4

eine offene Seitenansicht eines Regalmoduls.

The invention is explained in more detail below using exemplary embodiments with reference to the drawings. Show it:

Fig. 1

A refrigerated shelf with three shelf modules lined up next to each other (not yet fully assembled) in a perspective view from the front, side,

Fig. 2

a schematic view of two cooling shelves made of two shelf modules or three shelf modules with schematically shown components of a cooling device with a connection to a central recooling device,

Fig. 3

a perspective view of a refrigerated shelf from diagonally to the front in a side-open view and

Fig. 4

an open side view of a shelf module.

Fig.1 shows a refrigerated shelf 1 suitable for installation in a sales room according to claim 1 with three shelf modules 1.1, 1.2, 1.3 (so-called three-axis version), the refrigerated shelf 1 comprising a cold room 4 accessible from the front on the back and above and below through wall groups. The refrigerated shelf 1 can be combined with further refrigerated shelves 1 to form a refrigerated shelf arrangement, the refrigerated shelves 1 also being made of fewer shelf modules 1.1, 1.2, 1.3, e.g. B. two two-axis versions) or even just one (single-axis version), so that the length of the cooling shelf is preferably one or more times a module length (usually 1.25 m). When in use, side walls are preferably also attached laterally on both sides of the refrigerated shelf 1 or the refrigerated shelf arrangement. The front can be openly accessible or can be provided with at least one door element for special applications. To close e.g. B. in sales-free times, the front can be closed with a roller blind 63, which is arranged in the front roof area. When in use, there are 4 shelves in the cold room on which the refrigerated goods, such as meat products or dairy products or the like in a sales room, are placed.

To keep the cold room 4 cool, components of a cooling device 5 (cf. Fig. 2 ) integrated, namely a control unit 55.1 of a control device 55 (cf. Fig. 3 ) and fans 56, 57 to generate or support the necessary air flows (cf. Fig. 3 ), connecting means 53 including connecting lines 53.1 and, in a refrigerant circuit, an evaporator 50, 50 ', a compressor 51, a condenser 52 and an expansion valve arrangement. For monitoring purposes, additional pressure switches are integrated into the refrigerant circuit, preferably one on the high-pressure side and one on the low-pressure side, which are approved for operation with flammable refrigerants. Furthermore, pressure transmitters (e.g. one on the high-pressure side and one on the low-pressure side), a filter dryer and at least one sight glass on the high-pressure side are advantageously arranged in the refrigerant circuit. The circuit pipes are preferably made of copper, with brazing being used as the connection technique.

The condenser 52 can be connected via the corresponding connecting lines 53.1 via a secondary circuit to a recooling device 54 with a heat exchanger, preferably located in another room. If necessary, e.g. B. a larger refrigerated shelf arrangement also includes several similar components of the cooling device 5, in particular several refrigerant circuits. In the present exemplary embodiment, the refrigerated shelf 1 has only one refrigerant circuit in the case of a single-axis, two-axis or three-axis design.

Propane is used as a natural refrigerant in the refrigerant circuit, with the propane filling quantity being between 650 g and 800 g. This quantity has a length between z. B. 1 m and 4 m have proven to be particularly advantageous. For longer than e.g. B. three-axis refrigerated shelves, larger amounts of propane are also conceivable in a refrigerant circuit, but for safety reasons these should not exceed 1500 g. Smaller amounts are also part of the invention according to claim 1.

The refrigerated shelf 1 shown in the exemplary embodiments is particularly suitable for use with propane as a refrigerant in several respects, with some modifications being made compared to the variant operated with conventional refrigerant. One reason for the good suitability is in particular the modular structure with high flexibility with regard to the component arrangement, both components of the cooling unit 4 and other components. The structure also offers advantages in terms of efficiency, so that the relatively small amount of propane as a refrigerant, preferably 650 g and 800 g, is sufficient to apply the required cooling capacity in the cold room 4 of the refrigerated shelf 1, which in turn is beneficial for safety. The structure of advantageous design variants of the refrigerated shelf 1 is described in more detail below.

An essential part of each shelf module 1.1, 1.2, 1.3 are side frames 10 arranged on each side of the same, with a C-shaped shape in side view with a vertical profile 10.1 along the back, a lower horizontal profile 10.2 connected to it at the bottom and protruding forward, and an upper one at the top End section of the vertical profile 10.1 connected, forwardly projecting upper horizontal profile 10.3. In the illustration shown, the lower horizontal profile 10.2 projects further forward than the upper horizontal profile 10.3. Further investigations have shown that an upper horizontal profile 10.3 that is just as long or longer than the lower horizontal profile 10.2 can be advantageous, for example. B. to carry an upper stem with a roller blind and a lighting device stably and without deflection. In front of the vertical profile 10.1, a support profile 10.4 is installed at a distance to the front between the lower and upper horizontal profiles 10.2, 10.3. Between the upper and lower end faces of the support profile 10.4 and the upper and lower horizontal profiles 10.3, 10.2 there are block-like heat-insulating elements, for. B. made of good heat-insulating, stable plastic to avoid thermal bridges from the outside to the inside, which also results in advantageous assembly aids. The lower horizontal profile 10.2 is supported on feet 60, 61 with leveling options. The two side frames 10 form longitudinal elements connecting them, e.g. B. longitudinal struts and/or paneling parts, stable module frames with frame profiles. The two side frames 10 of each shelf module 1.1, 1.2, 1.3 or the module frames support the floor group 11 by means of their lower horizontal profiles 10.2, the rear wall group 12 by means of their vertical profiles 10.1 and support profiles 10.4 and the roof group 13 by means of their upper horizontal profiles 10.3 and result in a stable structure with simple assembly steps. In addition, they ensure a stable arrangement of several shelf modules 1.1, 1.2, 1.3 to form the refrigerated shelf 1 or the refrigerated shelf arrangement, with the refrigerated shelf 1 being able to be transported as a stable unit by means of a lifting device or vehicle.

The condenser 52 with corresponding connecting means 53 is arranged in or on the roof group 13 in an upper cooling component receptacle 13.30 formed there in the area of an upper cover 13.3, easily accessible from above or behind. A pressure vessel of a dryer/collector unit of the condenser 52 can be pressurized to a maximum pressure of up to 3,000,000 Pa or higher. It has a high bursting pressure, for example more than 13,000,000 Pa, so that a large safety distance from the operating pressure for the use of propane is guaranteed. The volume of the pressure vessel is between 0.4 l and 1.4 l, preferably between 0.5 l and 0.8 l, and is therefore significantly lower than that of conventionally used refrigerants, e.g. B. about half as large, depending on which conventional refrigerant is used. The pressure vessel has an elongated, cylindrical shape, which means that the pressure vessel can be arranged in or on the roof group to save space.

The compressor 51 is arranged in the lower area of the rear wall group 12 behind an inner cover 12.1 which delimits the cooling space 4 to the rear in a receiving chamber (not shown) of a receiving device. In terms of geodetic height, it is in the lowest area of the refrigerant circuit. In the middle area of the rear wall group 12, the evaporator 50, 50 'is also arranged behind the inner cover 12.1 and mounted with means of the receiving device. How out Fig. 1 As can be seen, the evaporator 50 'extends continuously over all three shelf modules 1.1, 1.2, 1.3, while the compressor 51 and the condenser 52 in a two- or three-axis design for all shelf modules 1.1, 1.2, 1.3 of the refrigerated shelf 1 together in just one, and although in the exemplary embodiment according to the Fig. 1 and 2 arranged in the right shelf module 1.1 (module b). and to the evaporator 50' via appropriate connecting lines Interposition of relevant intermediate members of the cooling device 5, such as expansion valve or throttle, are connected. The arrangement in just one shelf module 1.1, 1.2, 1.3 is advantageous when using propane in that the line length can be reduced compared to an arrangement in different shelf modules, which can reduce the number of potential leaks. In addition, a sufficient distance between the compressor 51 and the condenser 52 is ensured by the arrangement in different wall groups of the refrigerated shelf 1, namely the rear wall group 12 and the roof group 13, in order, for example, to avoid heat transfer from the compressor 51 to the condenser 52 and the formation of To prevent hot spots of excessive temperature development.

The floor assembly 11 delimits the cooling space 4 downwards with an overhead floor cover 11.1 and carries on its front a cover grille 11.10 provided with air passage holes, in particular air passage slots, and a front cover 11.4 with a bumper or decorative strip in the lower front edge area.

How Fig. 2 shows, an advantageous embodiment of the refrigerated shelf 1 according to claim 1 is that only one shelf module 1.1 with all components of a cooling device except for the possibly provided central recooling device 54 is provided with relevant outward and return connecting lines 53.1 (module with expansion type b), while the remaining shelf modules of a refrigerated shelf arrangement are only provided with an evaporator 50, 50', the evaporator 50, 50' being advantageously designed as a continuous unit (modules of expansion type a). If the refrigerated shelf 1 consists of only one shelf module 1.1, this shelf module 1.1 advantageously forms a module of expansion type b. The evaporator of the modules of expansion type a is connected via appropriate connecting means 53 including connecting lines 53.1 and optionally electrical cabling for signal transmission (sensors, control) and electrical energy supply connected to the other relevant components of the cooling device in the shelf module 1 of expansion type b. In order to ensure a refrigerated shelf 1 that is safe against ignition even with propane as a refrigerant, the electrical cabling and possibly other components are particularly secured against sparks, for example by plug connections that prevent sparks and/or special coatings. The distances between the conductor tracks, in particular of high-voltage lines, which are used to power electrical components with higher power consumption, are also increased compared to the refrigerated shelf version with conventional refrigerant, e.g. B. to at least 3 mm or at least 5 mm to avoid voltage flashover in any case. Furthermore, for example, a safety contactor is arranged in a main power line, although such a contactor can also be arranged in other critical areas. Advantageously, the control device 55, which contains a large number of electrical components, is additionally surrounded or encapsulated by a housing and is thus shielded from the environment.

However, all shelf modules 1.1, 1.2, 1.3 can be prepared in the same way to accommodate all the necessary components of the cooling device 5 and also with pre-installed sections of the connecting lines 53.1 and connecting means for a simple, quick connection between the cooling components of the shelf modules and, if necessary, with the central recooling device 54 , so that modules One expansion type can be converted into a module of the other expansion type with little assembly effort. For example, in a refrigerated shelf arrangement with a larger number of shelf modules, more than just one shelf module of expansion type b can be present.

An evaporator 50, 50' that extends over several shelf modules 1.1, 1.2, 1.3 can also be relatively easily inserted subsequently between the relevant vertical profiles 10.1 and the support profiles 10.4 located at a distance in front of them and attached to the vertical profiles and/or an intermediate partition, in particular an intermediate wall 12.2 become. The vertical profiles 10.1 in question and the support profiles 10.4 located at a distance in front of them advantageously form a continuous space that extends over several shelf modules 1.1, 1.2, 1.3. Subsequent installation is carried out e.g. B. by inserting the heat exchanger of the evaporator 50, 50 'from one side parallel to the rear wall plane or from the front, after the relevant support profiles 10.4 have been removed, which are then reinstalled. The special assembly method of the support profiles 10.4 results in easy installation and removal. For example, a one- or two-modular refrigerated shelf 1 can easily be extended to a two- or three-modular one simply by simply replacing the evaporator 50 to 50'. Other essential components of the refrigerant circuit can be retained, since with a uniform filling quantity, e.g. B. is between 650 g and 800 g, both single-axis and multi-axis (e.g. two- or three-axis) refrigerated shelves can be operated efficiently, as has been shown in the inventors' studies.

How Fig. 2 further shows, in the structure shown, only one shelf module 1.1 needs to be connected to the central recooling device 54 with the prepared connecting means 53, which contain, for example, quick couplings and controllable valves, while the remaining shelf modules 1.2, 1.3 only need to be connected via the integrated connecting means 53 in a simple manner be connected to each other. The central recooling device 54 is usually connected via the secondary circuit to the condenser 52 of the relevant shelf module 1.1 (expansion type b), with brine or a glycol/water mixture preferably being used as a coolant in the secondary circuit. For the condenser 52 z. B. a compact plate or tube heat exchanger, in particular a brazed plate heat exchanger with the countercurrent principle, can be used. Heat generated in the central recooling device 54 can be dissipated for other use of the thermal energy, as indicated by the arrow at the top right. With propane as a refrigerant, the central recooling device 54 has the additional advantage that, due to the distance from the refrigerated shelf 1, it is not subject to increased safety requirements and so no additional measures are required to secure it.

As the 3 and 4 , which also represent a refrigerated shelf according to claim 1, can be seen, the base group 11, the rear wall group 12 and the roof group 13 are designed in multiple layers with interconnecting spaces formed therein to form channels for the air flow. The air flow is effected or supported by fans 56, 57, which are designed, for example, as radial fans or diagonal fans and of which, in the exemplary embodiment shown, one is/are arranged in the lower region and one or two in the upper region of the rear wall group 12. The upper fan or fans 56 cause or cause the air flow through the evaporator 50, 50 ', from bottom to top. A portion of the cooling air flow formed by the evaporator 50, 50' is released again on the back of the inner cover 12.1 directed at the bottom and flows through ventilation slots in the inner cover 12.1 into the cooling chamber 4 in order to keep it at the required cooling temperature. In particular, the fan or fans 56 arranged above the evaporator 50, 50' have proven to be particularly effective and favorable for safety, although the fan 56 below the evaporator 50, 50' can be dispensed with.

The bottom cover 11.1, the inner cover 12.1 and the lower cover 13.1 of the roof group 13 are made of thin-walled plates, in particular made of metal or plastic, for good transmission of the cooling power to the cooling space 4, which are also easy to handle and clean. The plates of the floor cover 11.1 are advantageously segmented in the width direction and extend from the cover grid 11.10 in the front area of the floor group 11 to the lower area of the inner cover 12.1 of the rear wall group 12. The plates of the inner cover 12.1 of the rear wall group 12 are advantageously segmented and extend in the vertical direction over the entire width between the two side frames 10 of a shelf module 1.1, 1.2, 1.3, whereby several vertically stacked panels can be easily inserted or removed, for example. B. to expose, clean or install or remove relevant components of the cooling device 5.

As in Figures 3 and 4 can also be seen, tilt protection devices 62 which protrude downwards are attached to the lower end section of the vertical profiles 10.1, which advantageously adapt to uneven floors, e.g. B. allow by resilient or elastic intermediate elements and / or adjusting elements. A lighting device 64 can be arranged in the front area of the floor group 11 and/or the roof group 13. The lighting device 64 is advantageously designed as LED lighting with drivers tailored to it in order not to act as an ignition source in connection with the refrigerant used. In the front upper The roller blind 63 is advantageously arranged in the area, for. B. to close the cold room at the front outside of business hours and save cooling energy. The motor for driving the roller blind 63 is also provided with means to prevent sparks. For example, it is housed in a protective encapsulation and/or transition points that generate sparks in the area of live rotating parts must be avoided.

All in all, the above statements show a refrigerated shelf 1 according to claim 1 in a higher performance class (approximately > 2 kW), which can be operated in a climate-friendly, efficient and safe manner by using propane as a refrigerant. On the one hand, this is due to the fact that the embodiment variants shown have a basic structure with components arranged in an advantageous distribution, the structure of the shelf modules 1.1, 1.2, 1.3 and the refrigerated shelf 1 from the same enabling safe operation with propane.

Claims (14)

1. Refrigerated display case (1) with at least one unit composed of a plurality of wall groups, viz., a bottom group (11), a rear wall group (12), and a top group (13), which delimit a refrigerated chamber (4) at a bottom, at a back, and at a top, and with a cooling device (5) that has a refrigerant circuit at least comprising an evaporator (50), a condenser (52), and an electrical control device (55) as components, and containing propane as the refrigerant, wherein the cooling device (5) has a compressor (51) as further components,
   characterized in that

   propane is contained as the refrigerant in the refrigerant circuit, with a filling quantity between 300 g and 1,500 g,

   that the compressor (51) and the condenser (52) are arranged spaced apart from each other in different wall groups, wherein the compressor (51) is arranged beneath the evaporator (50) in the lower region of the rear wall group (12), and the condenser (52) is arranged on or in the top group (13), and a pressure vessel of a dryer/collector unit of the condenser (52) has a volume of between 0.4 L and 1.4 L,

   that the evaporator (50) is arranged in the rear wall group (12), and

   that the refrigerant circuit has a low-pressure region with an operating pressure between 80,000 Pa and 200,000 Pa and a high-pressure region with an operating pressure between 2,000,000 Pa and 3,000,000 Pa.
2. Refrigerated display case (1) according to claim 1,
   characterized in that
   propane is contained as the refrigerant in the refrigerant circuit, with a filling quantity between 500 g and 900 g.
3. Refrigerated display case (1) according to any of the preceding claims,
   characterized in that
   at least one fan (56) for assisting the flow of cooling air is arranged above the evaporator (50) in the rear wall group (12).
4. Refrigerated display case (1) according to claim 3,
   characterized in that
   the fan(s) (56, 57) has/have a motor overtemperature protection.
5. Refrigerated display case (1) according to any of the preceding claims,
   characterized in that

   the control device (55) is arranged at - in particular, in or on - the top group (13), and/or

   that the control device (55) is protectively enclosed in a housing.
6. Refrigerated display case (1) according to any of the preceding claims,
   characterized in that
   the components of the cooling device (5) arranged in the refrigerant circuit have a maximum surface temperature of less than 300 °C - preferably of less than 160 °C - during operation.
7. Refrigerated display case (1) according to any of the preceding claims,
   characterized in that

   the compressor (51) is designed as a fully hermetic, suction gas-cooled compressor - in particular, a scroll compressor - and

   that the compressor (51) is arranged in the lowest region of the refrigerant circuit in terms of geodetic altitude.
8. Refrigerated display case (1) according to any of the preceding claims,
   characterized in that
   electrical equipment used on the refrigerated display case (1) is at least partially provided with spark suppression.
9. Refrigerated display case (1) according to claim 8,
   characterized in that

   at least one safety relay is arranged in a main circuit of the refrigerated display case (1),

   that at least a portion of electrical components are provided with a sparksuppressing coating,

   that the conductor track spacings of the high-voltage lines are at least 3 mm, and/or

   that spark-preventing plug connections are used.
10. Refrigerated display case (1) according to any of the preceding claims,
    characterized in that
    the evaporator (50) comprises a heat transmission device with aluminum fins and/or copper tubes that have an inner diameter of between 10 mm and 15 mm and/or a maximum volume of between 3 L and 7 L.
11. Refrigerated display case (1) according to any of the preceding claims,
    characterized in that
    the condenser (51) comprises a plate heat exchanger that operates in accordance with a counterflow principle, on whose warm side the flow rate of propane is up to 100 kg/h - preferably up to 80 kg/h - and on whose cold side a glycol/water mixture is used as a coolant in a secondary cooling circuit.
12. Refrigerated display case (1) according to any of the preceding claims, characterized in that

    the refrigerated display case (1) comprises at least two display case modules (1.1, 1.2, 1.3) which can be arranged in a row with each other and are composed of identical module frames, with side frames (10) that have frame profiles and that support the bottom group (11), the rear wall group (12), and the top group (13) with respective casing parts, and

    that the display case modules (1.1, 1.2, 1.3) are provided with the shared evaporator (50) that is arranged in the rear wall group (12) and extends across a plurality of or all the display case modules (1.1, 1.2, 1.3).
13. Refrigerated display case (1) according to any of the preceding claims,
    characterized in that
    the side frames (10) are C-shaped when viewed from the side.
14. Refrigerated display case (1) according to any of the preceding claims,
    characterized in that

    a front roller shade (63) that is operated by a roller shade motor is accommodated in the front section of the top group (13), and

    that the roller shade motor has a spark-preventing design and/or is accommodated in a protective encapsulation.

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