EP3311083A1

EP3311083A1 - Cooling shelf

Info

Publication number: EP3311083A1
Application number: EP16717905.0A
Authority: EP
Inventors: Reinhold Resch
Original assignee: AHT Cooling Systems GmbH
Current assignee: AHT Cooling Systems GmbH
Priority date: 2015-06-16
Filing date: 2016-05-13
Publication date: 2018-04-25
Anticipated expiration: 2036-05-13
Also published as: EP3311083C0; CN107532838A; BR112017018256A2; US20180146799A1; AR105021A1; CN107532838B; DE102015109611A1; EP3311083B1; WO2016202486A1; US10368659B2

Abstract

The invention relates to a cooling shelf (1) having at least one unit composed of a plurality of wall groups, namely a base group (11), a rear wall group (12) and a top group (13), which delimit a cooling space (4) from below, the rear and above, and having a cooling device (5) with a refrigerant circuit, which comprises, as components, at least one compressor (51), an evaporator (50), a condenser (52) and an electric control device (55). An environmentally friendly, efficient and hence safely operable cooling shelf is obtained in that propane is contained as a coolant in the refrigerant circuit with a filling amount of more than 150 g.

Description

refrigerated

The invention relates to a refrigerated shelf having at least one unit comprising a plurality of wall groups, namely a floor assembly, a rear wall group and a roof group, which delimit a cooling space at the bottom, rear and top, and a cooling device having a refrigerant circuit, which as components at least one compressor, an evaporator, a condenser and an electrical control device.

A cooling rack of this kind is apparent, for example, from DE 10 2012 107 713 A1. It is particularly suitable for use in enclosed spaces and is characterized by a stable construction and a simple variation of the size of the cooling rack, which also allows the cooling of larger quantities of refrigerated goods. Refrigerated cabinets with a higher refrigeration capacity (about> 2 kW) are nowadays usually still operated with conventional, generally fluorinated refrigerants, especially when used in closed rooms. One reason is the properties of alternative, natural refrigerants, such as carbon dioxide or hydrocarbons, which make natural refrigerants not readily applicable in existing systems.

For example, hydrocarbons such as propane or butane as natural refrigerants are subject to restrictive regulations (eg, IEC 600335-289) because of their ignitability, according to which their contents are limited to up to 150 g per refrigerant cycle in conventional refrigeration 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 confined areas, so that a considerable effort is required to meet these requirements.

Due to the high cost, hydrocarbons in refrigerated cabinets for interior spaces are usually, if at all, used in refrigerant circuits with capacities up to a maximum of 150 g, so that generally only smaller performance classes are used with hydrocarbons (cf., for example, Climate Change 17/2014, Dr Michael Kauffeld, study "Decentralized plug-in refrigeration units", Federal Environmental Agency 2014, Table 3).

To be able to use hydrocarbons even at higher power levels, one manages with relatively complex systems, such as through the use of multiple cooling circuits, each having a maximum of 150 g of refrigerant to meet the safety requirements. Here is every cycle with separate components such as condenser or compressor. Such a system is specified, for example, in DE 10 2015 106 620 of the Applicant (still unpublished at the time of filing). In DE 20 2007 015 832 U1 a display cabinet is provided with an electrically powered roller blind. The use of a natural refrigerant, in particular with a coolant amount of greater than 150 g, is not mentioned.

Because of the conflicting problems, natural refrigerants at higher performance classes have, despite good suitability z. B. with respect to global warming potential, availability and thermodynamic properties not enforced as a refrigerant. Rather, fluorinated refrigerants are still used, which may be disadvantageous from an environmental point of view, in particular with regard to global warming potential.

The invention has for its object to provide a cooling rack of the type mentioned, the climate-friendly, efficient and safe to operate.

This object is achieved with the features of claim 1. In connection with the structural design taught in the preamble, it is provided that propane with a filling quantity of more than 150 g is contained in the refrigerant circuit as the refrigerant. As has been found in investigations by the inventors, higher cooling capacities of, for example, more than 2 kW using propane as a natural refrigerant can be efficiently covered with its positive properties with regard to greenhouse potential, availability and thermodynamic properties. In particular, larger refrigerated shelves, which may consist of several units or shelf modules, can be operated with only one propane-leading refrigerant circuit in this way. For example, one Cooling rack with a length of more than 2 m, in particular a so-called multiaxial cooling rack of several (eg., Two or three) rack modules (each, for example, 1, 25 m in length), with only one refrigerant circuit operable, including at longer cooling shelves a high cooling capacity is maintained, as has further been shown in investigations of the inventors. If a cooling rack of this length does not need to use a plurality of refrigerant circuits, this has a favorable effect on the reduction of the complexity, since inter alia 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 and on the operating costs of z. As compared to the use of multiple refrigerant circuits with quantities below 150 g.

In connection with said structure, a filling amount of propane between 300 g and 1500 g in the refrigerant circuit to achieve the required cooling capacity is advantageous. Filling quantities above 1500 g, for which already stricter regulations apply, are not required. Be particularly advantageous, a filling amount between 500 g and 900 g, in particular between 650 g and 800 g has been found, as hereby also common z. B. can operate two- or three-axis cooling shelf sizes with a cooling device having only a refrigerant circuit. Surprisingly, it has been found that a certain amount of charge advantageous z. B. can be used for a single-axis and multi-axis cooling rack, so that with a designed cooling device with relatively minor modifications, such as. B. evaporator length, different lengths cooling shelves can be operated with the required cooling capacity. Since largely identical components can therefore be used for different shelf lengths, This can have an advantageous effect on warehousing and installation measures. However, in order to optimize refrigerated shelves of different lengths, in spite of similar filling quantities in the circuit, it may also be advantageous to install different components.

Advantages, for example, in terms of operation and the cooling effect arise when the refrigerant circuit has a low pressure region with an operating pressure between 0.8 and 2.0 bar and a high pressure region with an operating pressure between 20 and 30 bar. The maximum allowable pressure in the low pressure circuit is z. B. 17 bar. In this case, the low-pressure region is located downstream of an expansion element and in particular comprises the evaporator. The high pressure region extends from the compressor to upstream of the expansion device and includes the condenser. In an advantageous embodiment variant of the cooling rack, the compressor and the condenser are spaced from each other, in particular arranged in different wall groups. The evaporator is preferably arranged in the rear wall group, since, for example, a large area is available for heat exchange with the cooling space, so that an efficient cooling of the cooling material can be achieved. Furthermore, the rear wall group can offer a cheap installation space. The spaced arrangement of compressor and condenser, which is advantageously arranged on or in the roof group, allows a favorable placement of these individual components, for example, in terms of function, accessibility, space utilization and installation measures. Relating to Propane as a refrigerant also has the advantage that can be avoided by the distributed arrangement of the components of heat esters, since there is no addition of heat through several heat-generating elements in a small space. This measure thus contributes to avoiding high temperatures that could be critical with respect to propane ignition point.

It is advantageous if the compressor is arranged in the lower region of the rear wall group below the evaporator and if at least one fan for supporting the cold air flow above the evaporator in the rear wall group is arranged.

The increased safety requirements in connection with propane, it is beneficial if the or the fan has a motor over-temperature protection / exhibit. In this way, high engine temperatures can be avoided, as might occur, for example, when the fan motor is defective. Advantageously, the blades of the fan can furthermore be made of a special material that prevents sparking, in particular plastic, or be coated accordingly. The use of valves, z. As solenoid valves, which are particularly secured against sparking and / or overheating, is advantageous in connection with propane. A further advantageous measure to this end is to dispense with a commonly used brine valve, as 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, extensive 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 at the same time easily accessible and protected placeable. A safe operation in connection with propane contributes to the fact that the control device is surrounded by a housing, for example a metallic housing, in a shielding manner, this also offering protection against environmental influences such as moisture, in particular splash water, and damaging influences on electrical components , Such a housing shields electrical components in the control device additionally from the propane-leading refrigerant circuit.

Another safety advantage results 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 Propan of 470 ° C to cause no ignition even in the unlikely event of a release of propane from the refrigerant circuit and formation of an ignitable mixture.

Preferably, the compressor is designed as a fully hermetic and suction gas cooled compressor, in particular as a scroll compressor. The hermetic closure prevents the escape of propane into the environment. The cooling prevents excessive heating of the compressor, which on the one hand safety, on the other hand with respect to the life of the compressor is beneficial. Moreover, if the compressor is located in the deepest part of the refrigerant circuit with respect to the geodetic height, this will facilitate the return of any oil in the refrigerant circuit, thus avoiding places in the circuit where oil accumulates. For safe operation of the cooling rack with propane is also advantageous if the electrical system used on the cooling rack is at least partially spark-proof. The electrics of the cooling rack includes, for example, the power supply of the individual components of the cooling device, but also the lighting, the rolling motor, etc., as well as connections for controlling and / or regulating components, possibly data connections and possibly other electrical. For example, areas where sparking can not be ruled out can be enclosed. The measures are advantageous in that at least one safety contactor is arranged in a main circuit of the cooling rack, which allows, for example, a monitoring of the contacts in the contactor. In addition, electrical components are preferably at least partially provided with a spark-suppressing coating. The components can be electrical components such. B. capacitors and the like, but z. As well as surfaces of components in the cooling device or other mechanical components. Also contributes to the suppression of sparking if the interconnect distances of the power lines at least 3 mm, z. B. between 3 and 5 mm, or at least 5 mm. In addition, in a preferred variant spark plug avoiding connectors can be used. Furthermore, the use of spark-proof relays and power supplies is advantageous, for. B. in the field of control device.

In an advantageous variant of the cooling rack, the evaporator comprises a heat transfer device with aluminum lamellae and / or copper tubes having an inner diameter between 8 mm and 20 mm, preferably between 10 mm and 15 mm (eg 12 mm) and / or have a maximum volume between 3 l and 7 l (eg 4 l and 6 l, respectively). With such a heat exchanger is, for. Due to the Used, good heat-conducting materials and a well-to-realize flat design, the cooling of the refrigerator in conjunction with propane as a refrigerant efficiently possible. Also conceivable would be other heat transfer devices that are suitable for use with propane.

A high degree of flexibility with regard to installation with high efficiency is achievable if the condenser comprises a (for example soldered) plate heat exchanger with countercurrent principle, on the warm side of which the flow of propane is up to 100 kg / h, preferably up to 80 kg / h the cold side of which is used as a refrigerant in a secondary cycle a glycol / water mixture. A mixture of water with 30-50% by volume (eg 38% by volume) of propylene glycol has been found 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 refrigerators, prevents ice from forming in the water. The coolant absorbs the enthalpy discharged from the propane by the propane and thus discharges it from the refrigerant circuit. It would also be conceivable air cooling of the refrigerant circuit, but air has a poorer thermal conductivity than a water mixture. In addition, the use of a glycol / water mixture in a secondary circuit, which are connected to the secondary circuit of several cooling units with their heat exchangers and the coolant in turn is supplied to a central recooling device, where it is cooled. Thus, such a recooling device can be arranged at a distance from the cooling shelf, in particular in a separate room, via a supply and return line, which brings advantages with regard to installation space and accessibility. In particular when used with propane, there is also the additional advantage that the recooling device can dispense with special safety measures, for example as described above, owing to its distance from the propane-conducting 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 of the same module racks with frame profiles having side frames, which carry the bottom group, the rear wall group and the roof group with respective trim parts and that the shelf modules with the in the back wall group arranged common evaporator are provided which extends over several or all shelf modules. By means of a varying number of rack modules arranged side by side, it is easy to produce refrigerated shelves of different lengths. In this case, a cooling rack of a plurality of shelf modules, in which a cooling device is used with a refrigerant circuit, in turn, be integrated as a module in a cooling rack assembly of several refrigerated shelves. In this way, a high flexibility in terms of the structure can be obtained. For a simple construction, the side frames preferably have a C-shape in lateral view.

An energy-efficient operation of the cooling rack can be achieved by a frontrollo driven by a roller motor is accommodated in the front section of the roof group. In this way, the refrigerator is at times when it does not need to be accessible, closable or concealable, so that the cooling performance can be reduced to maintain the product cooling temperature. In addition, the roller motor, which is advantageously positioned anyway in the overall structure, has a structure which avoids sparking and / or is accommodated in a shielding encapsulation. The structure avoiding sparking can be achieved, for example, as previously mentioned, by spark plug-avoiding plug connections, corresponding coatings or further measures. The encapsulation is advantageously gas-tight, so that in the case of a propane outlet from the refrigeration circuit no ignitable mixture enters the housing. So could itself in the If there is a spark on the rolling motor or in case of overheating due to a defect, ignite any ignitable mixture. The rolling motor can also advantageously be provided with a motor overtemperature protection, so that the motor is not operated when a certain temperature is exceeded.

The invention will be explained in more detail by means of embodiments with reference to the drawings. Show it:

1 is a cooling rack with three lined-up shelf modules (not yet fully assembled state) in a perspective view from the front, side,

2 is a schematic view of two refrigerated shelves of two shelf modules or three shelf modules with schematically illustrated components of a cooling device with a connection to a central recooling device,

Fig. 3 is a perspective view of a refrigerated shelf from obliquely laterally forward in laterally open representation and

Fig. 4 is an open side view of a shelf module.

1 shows a suitable for installation in a sales room cooling shelf 1 with three shelf modules 1.1, 1.2, 1.3 (so-called three-axle design), wherein the cooling rack 1 includes a front accessible refrigerator 4 on the back and up and down by wall groups. The cooling rack 1 can be combined with other refrigerated shelves 1 to a cooling rack assembly, the refrigerated shelves 1 also made less shelf modules 1.1, 1.2, 1.3, z. B. two biaxial design) or even one (single-axis design), may exist, so that the length of the cooling rack is preferably one or more times a module length (usually 1, 25 m). In use, side walls are preferably also laterally mounted on the two sides of the cooling rack 1 and the cooling rack assembly. The front can be open-access or be provided for specific applications with at least one door element. For closing z. B. in non-sales hours, the front can be closed with a roller 63, which is located in the front roof area. In use, 4 shelves are mounted in the refrigerator, on which the refrigerated goods, such as meat products or dairy products or the like. In a sales room, is launched.

For keeping the cooling space 4 cool, components of a cooling device 5 (see Fig. 2) are integrated in the cooling rack 1, in particular a control unit 55.1 of a control device 55 (see Fig. 3) and fans 56, 57 for generating or supporting necessary Air flows (see 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 assembly. For monitoring purposes, pressure switches, preferably one each on the high-pressure side and one on the low-pressure side, which are released for operation with flammable refrigerants, are additionally integrated in the refrigerant circuit. Furthermore, pressure transmitters (eg one each on the high pressure side and one on the low pressure side), a filter drier and at least one sight glass on the high pressure side in the refrigerant circuit are advantageously arranged. The pipelines of the circuit are preferably made of copper, being used as a joining technique brazing. The condenser 52 may be connected via the corresponding connecting lines 53.1 via a secondary circuit to a preferably located in another room recooling device 54 with a heat exchanger. If necessary, z. B. a larger cooling rack assembly also several similar components of the cooling device 5 include, in particular a plurality of refrigerant circuits. In the present embodiment, the cooling rack 1 in uniaxial, biaxial or triaxial design only a refrigerant circuit.

In the refrigerant circuit propane is fed as a natural refrigerant, wherein the amount of propane is between 650 g and 800 g. This amount has in the cooling rack 1 of said structure with a length between z. B. 1 m and 4 m proved to be particularly advantageous. For longer than z. B. three-axis refrigerators, larger amounts of propane in a refrigerant circuit are conceivable, but should not exceed 1500 g for safety reasons. Smaller quantities would also be conceivable.

The cooling rack 1 shown in the exemplary embodiments is particularly suitable for use with propane as a refrigerant in several respects, with some modifications being made in comparison with the variant operated with conventional refrigerant. One reason for the good suitability is in particular the modular design with high flexibility with respect to the component arrangement, both components of the cooling unit 4 and other components. Also, the structure offers advantages in terms of efficiency, so that the relatively small amount of propane is sufficient as a refrigerant of preferably 650 g and 800 g for applying the required cooling capacity in the cooling space 4 of the cooling rack 1, which in turn is beneficial to safety. The construction of advantageous design variants of the refrigerated shelf 1 will be described in more detail below. An essential part of each shelf module 1.1, 1.2, 1.3 are arranged on each side of the same side frame 10 with a side view C-shaped configuration with a vertical profile 10.1 along the back, a down at this connected and forward projecting lower horizontal section 10.2 and an upper, at the top End portion of the vertical profile 10.1 connected, forward 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. In further investigations it has been found that, however, an upper horizontal profile 10.3, which is just as long or longer than the lower horizontal profile 10.2, can be advantageous in order, for. B. an upper stem with blind and a lighting device stable and without bending to wear. In front of the vertical profile 10.1, a support profile 10.4 is installed at a distance from the latter, between the lower and upper horizontal profiles 10.2, 10.3. Between the upper and lower end side of the support section 10.4 and the upper and lower horizontal profile 10.3, 10.2 are block-like heat-insulating elements z. B. of good heat insulating, stable plastic mounted to prevent thermal bridges from the outside in, which also results in advantageous assembly aids. The lower horizontal profile 10.2 is supported on feet 60, 61 with leveling possibility. The two side frames 10 form with them connecting longitudinal elements, for. B. longitudinal struts and / or trim parts, stable modular racks with frame profiles. The two side frames 10 of each shelf module 1.1, 1.2, 1.3 or the module racks carry by their lower horizontal profiles 10.2 the bottom group 11, by means of their vertical profiles 10.1 and 10.4 support the rear wall group 12 and by means of their upper horizontal profiles 10.3 the roof group 13 and give a stable structure with simple assembly steps. In addition, they ensure a stable juxtaposition of several shelf modules 1.1, 1.2, 1.3 to the cooling rack 1 and the cooling rack assembly, wherein the cooling rack 1 is transportable as a stable unit by means of a lifting device or vehicle. The condenser 52 with corresponding connection means 53 is arranged in a preferred embodiment according to the embodiment shown in or on the roof group 13 in a formed there upper Kühlkomponentenaufnahme 13.30 in the region of a top cover 13.3 from above or behind easily accessible. A pressure vessel of a dryer / collector unit of the condenser 52 can be acted upon with a maximum pressure of up to 30 bar or higher. He has a high bursting pressure, for example, more than 130 bar, so that a large safety margin is guaranteed to the operating pressure for the use of propane. 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 thus significantly lower than conventionally used refrigerants, for. B. about half as large, depending on which conventional refrigerant is. In this case, the pressure vessel has an elongated, cylindrical shape, whereby the pressure vessel can be arranged to save space in or on the roof group.

The compressor 51 is arranged in the lower region of the rear wall group 12 behind a cooling cover 4 to the rear limiting inner cover 12.1 in a (not shown in detail) receiving chamber of a receiving device. It is located in the lowest range of the refrigerant circuit with respect to the geodetic height. In the middle region 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. As can be seen from FIG. 1, the evaporator 50 'extends continuously over all three shelf modules 1.1, 1.2, 1.3, while the compressor 51 and the condenser 52 are common for all shelf modules 1.1, 1.2, 1.3 of the refrigerated shelf 1 in two- or three-axle design in only one, namely in the embodiment of FIGS. 1 and 2 in the right shelf module 1.1 (module b) arranged and to the evaporator 50 'via corresponding connecting lines below Intermediate interconnecting links of the cooling device 5, such as expansion valve or throttle, are connected. The arrangement in only one shelf module 1.1, 1.2, 1.3 is advantageous in the case of using propane in that the line length can be reduced in comparison to an arrangement in different rack modules, which can reduce the number of potential leak sites. In addition, a sufficient distance between the compressor 51 and the condenser 52 is ensured by the arrangement in different wall groups of the cooling rack 1, namely the rear wall group 12 and the roof group 13, for example, to prevent heat transfer of the compressor 51 to the condenser 52 and the formation of Prevent hot springs from excessive temperature development.

The bottom group 11 delimited with an overhead floor cover 1 1 .1 the refrigerator 4 down and carries on its front a with Luftdurchtrittslö- ehern, in particular air passage slots, provided grille 1 1 .10 and a front cover 1 1.4 with bump or trim strip in lower front edge area.

As shown in FIG. 2, an advantageous exemplary embodiment of the refrigerated shelf 1 is that only one shelf module 1.1 is provided with all components of a cooling device except for the possibly provided central recooling device 54 with respective supply and return connecting lines 53.1 (module with type of expansion b), while the other shelf modules of a cooling rack assembly are provided with only one evaporator 50, 50 ', wherein the evaporator 50, 50' is advantageously designed as a continuous unit (modules of the expansion type a). If the cooling rack 1 consists of only one rack module 1 .1, this rack module 1.1 advantageously forms a module of the expansion type b. The evaporator of the modules of the expansion type a is connected via corresponding connection means 53 including connecting lines 53.1 and optionally electrical wiring for a signal transmission (sensors, control) and electrical power supply to the other relevant components of the cooling device in the shelf module 1 of the expansion type b connected. In order to ensure with propane as a refrigerant against ignition safe cooling rack 1, the electrical wiring and possibly other components, for example, by spark plug avoiding connectors and / or special coatings are particularly protected against sparking. In addition, the distances of the printed conductors, in particular from high-voltage lines which serve to supply power to electrical components of higher power consumption, are increased in comparison with the cooling rack design with conventional refrigerants, eg. B. at least 3 mm or at least 5 mm, to avoid a flashover in any case. Furthermore, a safety contactor is arranged, for example, in a main power line, wherein such can also be arranged in other critical areas. Advantageously, the control device 55, in which there is a large number of electrical components, additionally surrounded by a housing or encapsulated and thus shielded from the environment.

All shelf modules 1.1, 1.2, 1.3 can, however, in the same way for receiving all required components of the cooling device 5 and with preinstalled sections of the connecting lines 53.1 and connecting means for a simple, fast connection between the cooling components of the shelf modules and optionally with the central re-cooling device 54th be prepared so that modules

an extension type with low installation costs in a module of the other or possibly another type of expansion with other or other components of the cooling device can be converted. Also, for example, in a refrigerated shelf arrangement with a larger number of shelf modules more than just a shelf module of the expansion type b or a type of expansion with additional components of the cooling device may be present.

An over several shelf modules 1.1, 1.2, 1.3 continuous evaporator 50, 50 'can also be subsequently relatively easily between the respective vertical profiles 10.1 and the distance lying in front support profiles used 10.4 and attached to the vertical profiles and / or an intermediate partition, in particular an intermediate wall 12.2 become. Namely, the respective vertical profiles 10. 1 and the support profiles 10. 4 which are located at a distance from one another advantageously form a gap which also passes over a plurality of shelf modules 1. 1, 1. 2, 1. Subsequent installation takes place, for example. B. by inserting the heat exchanger of the evaporator 50, 50 'from one side parallel to the backplane or from the front after relevant support profiles have been removed 10.4, which are then reinstalled. The special way of mounting the support profiles 10.4 thus results in a simple installation and removal. Thus, for example, a one- or two-module refrigerated shelf 1 can simply be extended to a two- or three-module by the simple replacement of the evaporator 50 to 50 '. Other essential components of the refrigerant circuit can be maintained, since with a uniform amount, the z. B. is between 650 g and 800 g, both uniaxial and multi-axis (eg., Two- or three-axis) refrigerated shelves are efficiently operated, as has been found in studies of the inventors. To optimize a respective cooling rack design but also different components can be installed. As FIG. 2 further shows, only one shelf module 1.1 with the prepared connection means 53, which contain, for example, quick-release couplings and controllable valves, needs to be connected to the central recooling device 54, whereas the remaining shelf modules 1.2, 1.3 merely have the integrated Connecting means 53 are easily 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 (type of expansion b), wherein in the secondary circuit preferably a brine or a glycol / water mixture is used as a coolant. For the condenser 52 may, for. B. a compact plate or tube heat exchanger, in particular a soldered plate heat exchanger with countercurrent principle can be used. In the central recooling device 54 resulting heat can be dissipated for another use of thermal energy, as indicated by the arrow top right. With propane as the refrigerant, the central re-cooling device 54 additionally has the advantage that it is not subjected to increased safety requirements due to the distance to the cooling rack 1 and thus no additional measures are necessary for its protection.

As can be seen in FIGS. 3 and 4, the base group 11, the rear wall group 12 and the roof group 13 are configured in a multi-layered manner with interspaces formed between them for forming channels for the air guidance. The air duct is effected or assisted by means of fans 56, 57 which are designed, for example, as radial fans or diagonal fans and of which one is arranged in the lower region and one or two in the upper region of the rear wall group 12 in the embodiment shown. The or the upper fan 56 causes or thereby cause the flow of air through the evaporator 50, 50 ', from bottom to top. A portion of the cooling air flow formed by the evaporator 50, 50 'is on the back of the inner cover 12.1 again after passed down and flows through existing in the inner cover 12.1 vents in the refrigerator 4 to keep it at the required cooling temperature. In particular, the one or more fans 56 arranged above the evaporator 50, 50 'have proved to be particularly effective and favorable for safety, whereby the 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, which are also easy to handle and clean for a good transfer of cooling power to the refrigerator 4. The plates of the bottom cover 11.1 are advantageously segmented in the width direction and extend from the grille 11.10 in the front region of the bottom group 11 to the lower region 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 in the vertical direction and extend over the entire width between the two side frames 10 of a shelf module 1.1, 1.2, 1.3, wherein a plurality of vertically stacked plates can be easily used and removed, for. B. uncovering relevant components of the cooling device 5, to clean or to install or remove.

As can also be seen in FIGS. 3 and 4, anti-tilt devices 62 projecting downwards are attached to the lower end section of the vertical profiles 10. 1, which advantageously provide an adaptation to unevenness in the ground, for example. B. by resilient or elastic intermediate elements and / or adjusting allow. In the front region of the floor assembly 11 and / or the roof group 13, a lighting device 64 may be arranged. In this case, the illumination device 64 is advantageously designed as LED illumination with matched drivers so as not to act as an ignition source in connection with the refrigerant used. In the front upper Area is advantageous the roller 63 is arranged to z. For example, close the cold storage room outside the store hours and save cooling energy. The motor for driving the roller blind 63 is also provided with spark-preventing means. For example, it is accommodated in a protective encapsulation and / or spark-generating transition points in the area of live rotating parts are to be avoided.

All in all, the above explanations show a refrigerated rack 1 in a higher performance class (for example> 2 kW), which can be operated climate-friendly, efficiently and safely by using propane as a refrigerant. This is due, on the one hand, to the fact that the embodiments shown have a basic structure with components arranged in an advantageous distribution, the construction of the shelf modules 1.1, 1.2, 1.3 and the refrigerated shelf 1 from the same enabling safe operation with propane. In conjunction with this, modifications have been made which have proved to be useful in more extensive investigations than operational safety. With the measures according to the invention a cooling rack is provided with a capacity of more than 150 g of propane, which meets the increased safety requirements in such quantities.

Claims

1. refrigerated shelf (1) having at least one unit of a plurality of wall groups, namely a bottom group (1 1), a rear wall group (12) and a roof group (13) defining a cooling space (4) below, back and above, and with a A refrigeration system (5) having a refrigerant circuit and comprising as components at least one compressor (51), an evaporator (50), a condenser (52) and an electrical control device (55), characterized

that is contained as refrigerant propane with a capacity of more than 150 g in the refrigerant circuit.

Cooling shelf (1) according to claim 1,

characterized,

that is contained as a refrigerant propane with a capacity of between 300 g and 1500 g, preferably between 500 g and 900 g in the refrigerant circuit.

Cooling shelf (1) according to claim 1 or 2,

characterized,

the refrigerant circuit has a low-pressure region with an operating pressure between 0.8 and 2.0 bar and a high-pressure region with an operating pressure between 20 and 30 bar.

Cooling shelf (1) according to one of the preceding claims,

characterized,

in that the compressor (51) and the condenser (52) are spaced apart, in particular arranged in different wall groups, and in that the evaporator (50) is arranged in the rear wall group (12). Cooling shelf (1) according to claim 4,

characterized,

in that the compressor (51) is arranged in the lower region of the rear wall group (12) below the evaporator (50) and that at least one fan (56) for supporting the cold air flow is arranged above the evaporator (50) in the rear wall group (12).

Cooling shelf (1) according to claim 5,

characterized,

in that the fan or fans (56, 57) have motor overtemperature protection.

Cooling shelf (1) according to one of the preceding claims,

characterized,

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

that the control device (55) is surrounded by a housing shielding.

Cooling shelf (1) according to one of the preceding claims,

characterized,

that the components of the cooling device (5) arranged in the refrigerant circuit have a maximum surface temperature of less than 300 ° C., preferably less than 160 ° C., during operation.

9. refrigerated shelf (1) according to one of the preceding claims,

characterized,

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

in that the compressor (51) is arranged with respect to the geodetic height in the lowest region of the refrigerant circuit.

0. Cooling rack (1) according to one of the preceding claims,

characterized,

that electricity used on the cooling rack (1) is at least partially spark-proof secured.

1. refrigerated shelf (1) according to claim 10,

characterized,

in that at least one safety contactor is arranged in a main circuit of the cooling rack (1),

that electrical components are at least partially provided with a spark-suppressing coating,

that the interconnect distances of the high voltage lines are at least 3 mm and / or

that spark plug avoiding connectors are used.

2. refrigerated shelf (1) according to one of the preceding claims,

characterized,

in that the evaporator (50) comprises a heat transfer device with aluminum lamellas and / or with copper tubes having inside diameters between 10 mm and 15 mm and / or a maximum volume between 3 l and 7 l.

13. Cooling rack (1) according to one of the preceding claims,

characterized,

that the condenser (51) comprises a plate countercurrent plate heat exchanger, on the warm side of which the flow rate of propane is up to 100 kg / h, preferably up to 80 kg / h, and on its cold side as coolant in a secondary cooling circuit a glycol / Water mixture is used.

14. Cooling rack (1) according to one of the preceding claims,

characterized,

the refrigerated shelf (1) comprises at least two shelf modules (1.1, 1.2, 1.3) which can be lined up and which are constructed from identical module racks with side frames (10) having frame profiles, which cover the floor unit (11), the rear wall group (12) and the roof group (11). 13) with the respective trim parts and

the shelf modules (1.1, 1.2, 1.3) are provided with the common evaporator (50) arranged in the rear wall group (12), which extends over several or all shelf modules (1.1, 1.2, 1.3). 15. Cooling rack (1) according to one of the preceding claims,

characterized,

in that the side frames (10) have a C-shape in lateral view.

16. refrigerated shelf (1) according to one of the preceding claims,

characterized,

a frontrollo (63) driven by a rolling motor is received in the front section of the roof group (13) and that the rolling motor has a structure avoiding sparking and / or is accommodated in a shielding encapsulation.