WO2006047797A1

WO2006047797A1 - Method for preserving food and presentation shelf for food

Info

Publication number: WO2006047797A1
Application number: PCT/AT2005/000077
Authority: WO
Inventors: Gerhard Doczekal; Peter Schaberl
Original assignee: Gerhard Doczekal; Peter Schaberl
Priority date: 2004-11-05
Filing date: 2005-03-08
Publication date: 2006-05-11
Also published as: AT500980A1; CN101098646A; EP1809145A1; AT500980B1

Abstract

The invention relates to a method for preserving food (2), especially fruit and vegetables, in open presentation shelves (1). Air (K) cooled by an evaporator (8) is guided over the food (2) and the heat extracted from the food (2) is removed by a heat exchanger (9). The invention also relates to a corresponding presentation shelf (1). The aim of the invention is to provide a method by which means the preservability of food (2) can be increased and production and assembly costs are as low as possible. To this end, the air (K) in the evaporator (8) is cooled by means of a cooling liquid, especially water, having an inlet temperature (TE) of more than 0 °C, preferably 4 °C, and the evaporator (8) is sized in such a way that the cooling air (K) has a relative humidity (FK) higher than the relative humidity (FU) of the ambient air.

Description

Process for the preservation of food and presentation shelves for food

The invention relates to a method for preserving food, in particular fruit and vegetables, in open presentation shelves, wherein cooled air is passed over the food by means of an evaporator and the heat extracted from the food is removed via a heat exchanger.

Furthermore, the invention relates to a presentation shelf for food, especially for fruit and vegetables, arranged on a "back wall soils for holding the food and a system for guiding cooling air over the food with at least one fan for conveying the cooling air and zu¬ least one evaporator to lower the temperature of the cooling air and at least one heat exchanger for removing the heat extracted from the Lebens¬.

The present invention is directed primarily to fruits and vegetables which spoil particularly quickly and react particularly sensitively to changes in the temperature and humidity of the ambient air. Nevertheless, the method according to the invention and the presentation rack are also suitable for other foods, such as e.g. Fish, meat, dairy products but also Süß¬ goods, such as chocolate or cookies, applicable.

Usually fruits and vegetables are stored immediately after harvesting at very low temperatures in the range between 6 and 8 ⁰ C and transported at these temperatures in the sales outlets. In the case of fruit and vegetables in particular, it is necessary to present the goods on open shelves at the point of sale, so that the customer can inspect the goods and also attack them. The fruits and vegetables would permärkten at conventional temperatures of up to 25 ⁰ C in Su¬ spoil after a very short time and would have within short time frames ausge¬ be exchanged. Already at temperatures above 18 °, the spoilage of fruits and vegetables is progressing very rapidly and an infestation of fruit flies follows. In addition to too high a temperature of the ambient air is also a too low air humidity another parameter, the spoil, in particular of fruit and Vegetables, much faster. In particular, by Klima¬ systems, such as are now common in supermarkets, the humidity is reduced to particularly low values at which the fruit and vegetables quickly dries up and spoils.

The relatively short shelf life of the foodstuffs, in particular fruits and vegetables, results in increased product costs, manipulation costs in the shops and enormous logistics and disposal costs. Usually, fruits and vegetables are taken out of sales after 36 hours and replaced with new products. Apart from the bad optical condition of the products, spoilage also reduces important nutrients and vitamins more quickly.

To extend the shelf life of food, especially fruits and vegetables, cooled presentation shelves are einge¬ sets, by the storage temperature can be kept below 18 °. For this purpose, cooling air, which is cooled in an evaporator, blown over the food. When the air in the evaporator cools down, the moisture is usually removed, as a result of which the moisture is removed from the fruit and vegetables and the spoilage is further accelerated. Since the evaporator normally has a surface temperature below 0 °, the air moisture is bound to it and, as already mentioned, the refrigerated goods are deprived of more and more moisture, which finally leads to drying out of the products. As a remedy humidification systems are used, with which water is sprayed over nozzles on the food. This has the consequence that even more moisture is bound to the evaporator, this iced up faster and the cooling capacity is greatly reduced. In addition, the food is uncontrollably provided with moisture, which is inadmissible for many products. Finally, the moisture can lead to mold and to a visual impairment of the food. Also, the cleaning effort is significantly increased by excessive moisture precipitation.

DE 198 28 306 A1 describes a process for the preservation of fruit or vegetables, wherein the food flows through cooled in a heat exchanger air. Furthermore In order to prevent the formation of germs, the cooling air is passed through a degerminator with ultraviolet radiation to kill the microorganisms contained in the cooling air. Precise information about the type and humidification of the cooling air are not made.

No. 5,440,894 A shows a cooling device in which a coolant circulates from a remote source to the corresponding heat exchangers in order to be able to ensure cooling at a substantially constant temperature.

US 2002/0062654 A1, US Pat. No. 5,317,881 A and US Pat. No. 5,315,837 A showcase presentation racks of the type in question, in which appropriately cooled air is passed over the goods to be cooled.

US Pat. No. 6,390,378 B1 describes a container for the transport of perishable goods, which has a source of moisture, so that a desired relative fugacity of 90% or greater can be achieved.

DE 85 24 577 Ul describes a display rack of gegen¬ type with a system for the circulation of cooling air over the food, the refrigeration unit is turned on in response to the ambient temperature. For moistening the cooling air, a Verdunsterwanne is arranged below the evaporator. This also results in an uncontrolled humidification of the cooling air and an increased cleaning effort.

Finally, US Pat. No. 5,477,702 discloses a refrigerated presentation device for foods, which is characterized by special guides of the cooling air streams. On the type of cooling and a possible moistening of the cooling air is not eing¬ gone.

The object of the present invention is to provide an above-mentioned process for the preservation of foodstuffs, in particular fruit and vegetables, by means of which a particularly long shelf life can be achieved with at the same time the least possible outlay and the lowest possible costs. representation In addition, the nutritional value of the food should remain as long as possible.

A further object of the present invention is to provide an above-mentioned presentation shelf for foodstuffs, in particular for fruits and vegetables, by means of which the longest possible shelf life of the food can be achieved while at the same time minimizing assembly and costs. Existing presentation shelves should be able to be converted easily and quickly.

Disadvantages of the prior art should be avoided or reduced.

The first object of the invention is achieved in that the air is cooled in the evaporator by means of a cooling liquid having an inlet temperature of more than 0 ⁰ C, preferably from 4 ⁰ C and that the evaporator is dimensioned so that the cooling air has a relative humidity , which is above the relative humidity of the ambient air. By using a cooling liquid with more than 0 ⁰ C, preferably 4 ⁰ C in the evaporator, the evaporator operates at temperatures above 0 ⁰ C, whereby no moisture is bound to the evaporator and thus this of the air is not removed. Since no moisture in the evaporator is thus removed, the absolute humidity of the cooling air during the passage through the evaporator remains essentially the same, which results in a decrease in the relative humidity of the air when the temperature of the cooling air drops. By appropriate dimensioning of the working end at temperatures above 0 ⁰ C evaporator is therefore an increase in the relative atmospheric humidity possible with respect to the ambient air. Thus, both the reduction of the temperature and the increase of the relative humidity without active irrigation of the food with water is achieved by the inventive method. Thus, the condensation of air humidity can be reduced or avoided, whereby on the one hand the optical state of the food can be improved, and the cleaning effort can be reduced. As will be explained below with reference to an example, could in experiments with the inventive method D a shelf life of fruits and vegetables of up to 120 hours er¬ aims. Thus, the usual maximum period of 36 hours can be increased more than three times.

Advantageously, water is used as the cooling liquid for cooling the air. Water is a biologically totally unthinkable material, which is also available substantially everywhere and relatively inexpensively.

Advantageously, the cooling air is cooled to a temperature of 10-18 ⁰ C, preferably to 13-15 ⁰ C. In this area, a very long shelf life of the food is achieved.

The relative humidity of the cooling air is advantageously 10-30% above the relative humidity of the ambient air. The advantage of the present method is that to increase the humidity no active contribution of moisture must be made, but this is done automatically by the appropriate dimensioning of the evaporator.

According to a further feature of the invention, the temperature of the cooling air and / or the ambient air as well as the humidity of the cooling air and / or the ambient air can be measured with corresponding sensors. This can serve on the one hand for quality control or for controlling the cooling.

To check the operation of the evaporator, the moisture of the cooling air can be measured before entering the evaporator and after leaving the evaporator and, for example, if an alarm is triggered, if certain limit values are exceeded.

According to a further feature of the invention, the delivery of the cooling liquid can be regulated as a function of the temperature of the cooling air and / or the temperature of the ambient air and / or the humidity of the cooling air and / or the humidity of the ambient air. Thus, depending on the respective environmental conditions, the cooling can be changed and thus the energy requirement can be reduced to a minimum. - Q -

Likewise, the speed of the cooling air can be regulated as a function of the temperature of the cooling air and / or the temperature of the ambient air and / or the humidity of the cooling air and / or the humidity of the ambient air. It is a goal to keep the cooling air velocity as low as possible, on the one hand to reduce the energy consumption and on the other hand to keep the occurring to a certain extent dehumidification of the food low. The speed of the cooling air is preferably achieved by changing the speed of the fans.

Advantageously, the inlet temperature of the coolant of the evaporator is also measured with corresponding sensors.

To avoid a drop in the operating temperature of the evaporator Ver¬ below a certain value, in particular below 4 ⁰ C, the heat dissipation can be stopped, which can be done for example by closing a valve in the Senkundärkreislauf the heat exchanger. Thus, no heat is dissipated by the heat exchanger and the temperature of the cooling liquid can not continue to decrease. As a result, icing of the evaporator and removal of atmospheric moisture by moisture precipitation on the evaporator is prevented.

Further monitoring can be carried out by measuring the flow of the cooling liquid through the evaporator with the aid of a sensor.

The second object according to the invention is achieved by a presentation rack mentioned above in which a liquid-cooled evaporator is used, the inlet temperature of the liquid coolant of the evaporator being more than 0 ^° C., preferably 4 ^° C., and the relative humidity of the cooling air above the relative humidity of the ambient air. By means of such a presentation shelf, a very long shelf life of the food, in particular fruit and vegetables, can be achieved in a particularly simple and cost-effective manner.

Advantageously, the liquid coolant is water educated. As already mentioned above, water is relatively cheap and is generally available everywhere and biologically harmless.

The temperature of the cooling air is 10-18 ⁰ C, preferably 13-15 ° C.

The relative humidity of the cooling air is advantageously 10-30% more than the relative humidity of the ambient air, in order to prevent the food from drying out and thus to extend the shelf life.

According to further features of the invention, sensors for measuring the temperature of the cooling air and / or the surrounding air and for measuring the humidity of the cooling air and / or the ambient air can be provided. Such sensors can be designed in various ways and on the one hand serve for monitoring for the purpose of quality control or be used as an input signal of a control circuit for controlling the cooling.

For the purpose of regulation, a control device may be provided, which is provided with a pump for circulating the cooling liquid and with a sensor for measuring the temperature of the cooling air and / or a sensor for measuring the temperature of the ambient air and / or a sensor for measuring the humidity of the cooling air and / or a sensor for measuring the humidity of the Umbegungsluft is connected. Thus, depending on the respective parameters, the circulation pump of the cooling liquid can be controlled differently, whereby the cooling can be increased or reduced.

Likewise, a control device can be provided, which with the at least one fan for conveying the cooling air and with a sensor for measuring the temperature of the cooling air and or or a sensor for measuring the temperature of the ambient air and / or a sensor for measuring the Moisture of the cooling air and or or a sensor for measuring the humidity of the ambient air is connected.

Furthermore, a sensor for measuring the inlet temperature of Coolant be provided in the evaporator. This can ensures ge that the evaporator at temperatures above 0 ⁰ C, preferably at 4 ⁰ C operates, and thus no withdrawal of humidity takes place from the air.

The sensor for measuring the entrance temperature of the Kühlflüssig¬ ness may be connected to a valve in the secondary circuit of the Wärme¬ exchanger so that the heat dissipation in the case of falling below the inlet temperature below a predetermined value, in particular below 4 ⁰ C, can be stopped.

Furthermore, at least one sensor for measuring the flow of the cooling liquid can be provided in order, for example, to be able to display the correct operation of the cooling rack and, on the other hand, to output an alarm if the limit values are undershot or exceeded.

To form a channel for guiding the cooling air, the rear wall of the presentation rack can be double-shelled, the cooling air entering the channel from below after exiting the evaporator and exiting through the outlet openings above the trays for cooling the food arranged on the trays. This represents a simple embodiment variant of the presentation rack, which also makes it possible to quickly retrofit uncooled shelves by replacing the rear wall.

In order to reduce turbulences in the air flow of the cooling air, the outlet openings can be formed by pipes arranged side by side, which for example have honeycomb-shaped cross sections. As a result, a laminar air flow is achieved which ensures cooling of even the foremost foods on the ground, even on particularly long shelves, and on the other hand entrains as little warm ambient air as possible, which would require increased energy expenditure for cooling the air.

To the direction of the air flow, the outlet openings can be made inclined. Frequently, the bottoms of the presentation shelves are also inclined forwardly. In this case, the inclination angle of the outlet opening is advantageous to the Slope of the floor of the presentation rack adjusted.

In order to adapt the cooling to the respective food but also to the respective loading of the floors of the presentation shelf, the outlet openings can also have adjustable inclination.

For guiding the cooling air in the channel inside the rear wall of the presentation shelf, means for guiding the cooling air can be provided. Such baffles or the like. Serve for branching of partial air flows in the direction of the outlet, so that even several superposed floors of the presentation rack can be sufficiently supplied with cooling air.

To save energy, the rear wall may have a thermal insulation of suitable material.

To guide the cooling liquid, in particular the water from the heat exchanger to the evaporator lines are provided, which may be formed, for example, of copper or plastic.

In order to lose as little energy through these lines, a thermal insulation can be provided from suitable material.

To refill the coolant, the coolant lines can be provided with a corresponding connection. Such a connection for the cooling liquid, in particular for water, can be formed by a conventional plug connection, to which, for example, a water hose can be connected in order to be able to fill water into the cooling circuit.

To reduce the energy losses, side walls may be provided for lateral delimitation of the presentation shelf, which prevent lateral leakage of the cooling air.

To create different areas, for storing, for example, various foods intermediate walls can be provided. As a result of this and by further measures, such as the arrangement of different evaporators, it is theoretically also possible to use presentation gadgets. Ie be created, which provide different temperature ranges for different foods.

Advantageously, the at least one fan and the at least one evaporator are arranged at the bottom of the presentation rack. Since the presentation of the food for reasons of convenience can not be made to the bottom of the shelf, this area is particularly suitable for the arrangement of such components. For maintenance and cleaning of the components they should be as easily accessible.

To accommodate condensation, a removable tray can be arranged on the bottom, which is preferably made of stainless materials, such as plastics. Likewise, the condensation can be absorbed by a channel.

To avoid noise pollution for the customers but also the staff, a sound insulation for the at least one fan can be provided.

Finally, advantageously, lighting can be arranged on the underside of the shelves of the shelf. In this case, the electrical connection of the lighting devices can be done by connectors that allow rapid assembly and disassembly.

The present invention will be explained in more detail with reference to the accompanying drawings.

Show in it

1 shows a sectional side view of an embodiment of a presentation rack;

FIG. 2 shows the plan view of the presentation rack according to FIG. 1 as seen by the customer; FIG. and

3 shows a schematic block diagram of the air cooling contained in the presentation rack according to the invention. Fig. 1 shows a sectional view of an embodiment of a presentation shelf 1 for food 2, especially for fruits and vegetables. In this case, a plurality of trays 4 for receiving the food 2 are angeord¬ net on a rear wall 3 in a conventional manner. For good support of the presentation shelf 1, the rear wall 3 is connected ver¬ with a corresponding shelf extension 5 with feet 6. At the upper end of the rear wall 3, a closure 7 may be arranged in the form of a roof. The cooling of the food 2 is carried out via cooling air K, which ge leads over the food 2, which has been indicated schematically by the dashed line and the arrows. The cooling air K is conveyed by at least one fan 7, which may be located in the lower area between the shelf extension arms 5. The fan 7 may be provided to reduce the noise with a sound insulation. The cooling air K is ge blown by an evaporator 8, the _κ the temperature T of the cooling air lowers K to appropriate values. To dissipate the heat extracted from the food 2, a heat exchanger 9, preferably arranged in the upper region of the shelf 1, which is connected via corresponding lines (not shown) to the evaporator 8. The Sekundär¬ circle of the heat exchanger 9 is connected via corresponding Kälte¬ medium lines (not shown) connected to a cooling unit, which is not normally arranged in the presentation rack 1 and may be formed in various ways. To guide the cooling air K, the rear wall 3 is preferably designed to be soundproofed to form a channel 10. To avoid the heating of the cooling air K through the environment, a corresponding thermal insulation 11 may be provided on the rear wall 3. The cooling air K enters after leaving the evaporator 8 from below into the channel 10 in the rear wall 3 and leaves this channel 10 through corresponding outlet openings 12, which are arranged above the trays 4. For guiding the cooling air K, guide devices 13, for example baffles or the like, can be arranged. For operation of the evaporator 8, a cooling liquid, in particular water is used, which is arranged by appropriate lines (not shown) to a pump 14, which is preferably arranged in the upper area of the presentation area 1 and to the heat exchanger 9 to remove the heat be guided. To illuminate the food 2 can appropriate Lighting body 15 may preferably be arranged on the underside of the bottoms 4.

To illustrate the outlet openings 12 for the cooling air K, reference is made to FIG. 2, which shows a plan view of the presentation shelf 1 from the perspective of the consumer. For better clarity, the floors 4 and 7 were not shown. The rear wall 3 has outlet openings 12 for the cooling air K, which may be formed, for example, in the form of juxtaposed tubes 16, for example with a honeycomb-shaped cross section, in order to achieve a laminar flow of the cooling air K. The presentation shelf 1 is laterally limited preferably by side walls 18, 19.

3 shows a schematic block diagram of the device for cooling and humidifying the food in the presentation rack 1. The block diagram shows a total of four evaporators 8, through which the air K for cooling the food 2 is blown by means of fans 7. For operating the evaporator 8 is a cooling liquid, in particular water, which is guided in ent speaking cooling lines 20 in the circuit. To avoid energy losses, the cooling liquid lines 20 are preferably provided with a heat insulation 21. The cooling liquid is passed from the evaporator 8 via a pump 14 to a heat exchanger 9 for discharging the heat and from this heat exchanger 9 back to the evaporators 8. For the possibility of replenishment of cooling liquid, a connection 22 can be connected to the lines 20, via which the cooling liquid, in particular the water, can be topped up. Erfindungsge¬ Mäss the evaporator 8 are formed so that the temperature T _E Eingangstem¬ comprises the cooling liquid above 0 ⁰ C, preferably 4 ⁰ C. In the circulation of the cooling liquid, a Aus¬ equalizing tank 23 may be arranged with a compensation valve 24. To dissipate the heat through the heat exchanger 9, a refrigerant via corresponding lines 25, 26 to a ent speaking cooling unit (not shown) out, which may be designed in various ways. To connect the presentation rack 1 with such a corresponding refrigeration aggregate, the coolant lines 25, 26 are preferably equipped with corresponding connection elements 27, 28. to Measurement of the inlet temperature T _{E of} the cooling liquid at the inlet of the evaporator 8, a corresponding sensor 29 may be provided. When falling below a certain temperature, spielsweise of 4 ⁰ C, the further heat dissipation can be stopped by the heat exchanger 9 by a solenoid valve 30 is actuated in the coolant line 25. For measuring the flow rate of the cooling liquid, a flow sensor 31 can be arranged in the line 20. For measuring the temperature T of the cooling air K, the temperature T _κ ₁₁ of ambient air and the atmospheric humidity F _κ the cooling air K and the humidity F ₀ of the ambient air can be also placed at appropriate locations sensors sake of clarity, not ein¬ are drawn. By means of a corresponding control device 32, which can be connected, for example, to the fans 7 and / or the pump 14 and the temperature sensors, regulation of the cooling of the food 2 is possible.

According to the invention by operating the evaporator 8 with a cooling liquid, in particular water, with a temperature in the range above 0 ⁰ C, in particular at 4 ⁰ C, achieved that the evaporator 8 of the cooling air K no moisture extracts, but it by cooling the cooling air K even increases the humidity of the cooling air K comes. Thus, a much higher durability of the food 2 is achieved.

The effect of the invention will be explained in more detail with reference to the following example:

Fruit and vegetables were stored in an uncooled rack and a shelf cooled in accordance with the present invention, and the temperature and humidity in the rack were measured. The used evaporator 8 has the following technical data:

Inlet temperature of the cooling liquid (water): 4 ^° C.

Outlet temperature of the coolant (water): 7 ⁰ C

Volume flow of the cooling liquid: 0.41 m hour

Volume flow of cooling air entering the evaporator: 400 m ³ / hour

Volume flow of cooling air exiting the evaporator: 389 m ³ / h Temperature of the cooling air entering the evaporator: 17.5 ° C Temperature of the cooling air exiting the evaporator: 10.5 ⁰ C relative humidity of the cooling air entering the evaporator: 64% relative humidity of the cooling air exiting the evaporator Evaporator: 84%

While the temperature in the refrigerated shelf in the range between 9.6 and 13 ° C, the temperature in the uncooled shelf was between 18.1 and 21.1 ° C. The air humidity in the cooled rack was between 80.2 and 99.2%, while in the uncooled rack only values of relative humidity between 60.3 and 83.1% could be recorded. While some of the tested fruits and vegetables were already spoiled after one day, with the presentation rack according to the invention the shelf life could be increased to 99 hours.

The present invention therefore shows a process for the preservation of foodstuffs, in particular fruit and vegetables, and a presentation rack for foods, in particular for fruits and vegetables, by which the shelf life of the foodstuffs is many times greater in a particularly simple and cost-effective manner can be increased compared to today's methods.

Claims

claims:

1. A method for preserving food (2), in particular fruits and vegetables in open presentation shelves (1), wherein by means of an evaporator (8) cooled air over the food (2) is guided, and the food (2) withdrawn heat via a heat exchanger (9) is discharged, da¬ characterized in that the air (K) in the evaporator (8) mit¬ means of a cooling liquid is cooled, which has an inlet temperature of more than 0 ⁰ C, preferably 4 ⁰ C. , And that the evaporator (8) is dimensioned so that the Kühl¬ air (K) has a relative humidity (F _κ ), which is above the relative humidity (Fu) of the ambient air.

2. The method according to claim 1, characterized in that water is used as the cooling liquid for cooling the air (K).

3. The method according to claim 1 or 2, characterized in that the cooling air (K) to a temperature (T _κ ) of 10 to 18 ⁰ C, preferably 13 to 15 ° C is cooled.

4. The method according to any one of claims 1 to 3, characterized gekenn¬ characterized in that the relative humidity (F _κ ) of the cooling air (K) by 10 to 30% above the relative humidity (F ₁₁ ) of the ambient air Umge¬.

5. The method according to any one of claims 1 to 4, characterized gekenn¬ characterized in that the temperature (T _κ ) of the cooling air (K) is measured.

6. The method according to any one of claims 1 to 5, characterized gekenn¬ characterized in that the temperature (T ₁₁ ) of the ambient air is measured.

7. The method according to any one of claims 1 to 6, characterized gekenn¬ characterized in that the moisture (F _κ ) of the cooling air is measured.

8. The method according to claim 7, characterized in that the moisture (F _κ ) of the cooling air (K) before entering the evaporator Ver¬ (8) and / or after exiting the evaporator (8) is measured.

9. The method according to any one of claims 1 to 8, characterized gekenn¬ characterized in that the moisture (Fu) of the ambient air is measured.

10. The method according to any one of claims 5 to 9, characterized gekenn¬ characterized in that the promotion of the cooling liquid in dependence of the temperature (T _κ ) of the cooling air (K), and / or the temperature (Tu) of the ambient air and or . or moisture (F _κ) of the cooling air (K) and respectively or the humidity (F _n) of the Umge¬ is controlled ambient air.

11. The method according to any one of claims 5 to 10, characterized gekenn¬ characterized in that the speed of the cooling air (K) in dependency of the temperature (T _κ ) of the cooling air (K), and or or the temperature (Tu) of Ambient air and / or humidity

(F _κ ) of the cooling air (K) and / or the humidity (F ₀ ) of the Um¬ ambient air is controlled.

12. The method according to any one of claims 1 to 11, characterized gekenn¬ characterized in that the input temperature (T _E ) of the cooling liquid of the evaporator (8) is measured.

13. The method according to claim 12, characterized in that falls below a certain value of the input temperature (T _E ) of the cooling liquid, the heat dissipation is stopped.

14. The method according to any one of claims 1 to 13, characterized gekenn¬ characterized in that at least one sensor (31) is provided for measuring the Durch¬ flow of the cooling liquid.

15. presentation shelf (1) for food (2), in particular for fruit and vegetables, with on a rear wall (3) arranged floors (4) for receiving the food and a system for guiding cooling air (K) on the food (2) , with at least one fan (7) for conveying the cooling air (K) and at least one evaporator (8) for lowering the temperature of the cooling air (K), and at least one heat exchanger (9) for removing the food (2 ) extracted heat, characterized characterized in that a liquid-cooled evaporator (8) is used, wherein the inlet temperature (T _E ) of the liquid coolant of the evaporator (8) is more than 0 ⁰ C, preferably 4 ⁰ C, and the relative humidity (F _κ ) of the cooling air ( K) is above the relative humidity (F _n ) of the ambient air.

16. Presentation shelf according to claim 15, characterized in that the liquid coolant is formed by water.

17. Presentation rack according to claim 15 or 16, characterized gekenn¬ characterized in that the temperature of the cooling air (K) is 10 to 18 ⁰ C, preferably 13 to 15 ° C.

18. Presentation shelf according to one of claims 15 to 17, da¬ characterized in that the relative humidity (F _κ ) of the cooling air (K) by 10 to 30% more than the relative humidity

(Fu) of the ambient air is.

19. Presentation rack according to one of claims 15 to 18, da¬ characterized in that at least one sensor for measuring the temperature (T _κ ) of the cooling air (K) is provided.

20. Presentation shelf according to one of claims 15 to 19, da¬ characterized in that at least one sensor for measuring the temperature (T ₁₁ ) of the ambient air is provided.

21. Presentation rack according to one of claims 15 to 20, da¬ characterized in that at least one sensor for measuring the moisture (F _κ ) of the cooling air (K) is provided.

22. Presentation shelf according to one of claims 15 to 21, da¬ characterized in that at least one sensor for measuring the moisture (Fu) of the ambient air is provided.

23, presentation rack according to one of claims 15 to 22, da¬ characterized in that a control device (32) is provided, which speed with a pump (14) for circulation of Kühlflüssig¬ and with a sensor for measuring the temperature (T _κ ) the cooling air (K) and / or a sensor for measuring the tempera ture (Tu) of the ambient air and or or a sensor for measuring the moisture (F _κ ) of the cooling air (K) and / or a sensor for measuring the humidity (F ₀ ) of the ambient air is connected.

24. Presentation rack according to one of claims 15 to 23, da¬ characterized in that a control device (32) is provided which with the at least one fan (7) for conveying the cooling air (K) and with a sensor for measuring the temperature ( T _κ ) of the cooling air (K) and / or a sensor for measuring the temperature (T _σ ) of the ambient air and / or a sensor for measuring the humidity (F _κ ) of the cooling air (K) and / or a sensor for Measurement of the humidity (F _n ) of the ambient air is connected.

25. Presentation shelf according to one of claims 15 to 24, da¬ characterized in that at least one sensor (29) for measuring the inlet temperature (T _E ) of the cooling liquid in the evaporator (8) is provided.

26. Presentation rack according to claim 25, characterized in that the sensor (29) for measuring the inlet temperature (T _E ) of the cooling liquid with a valve (30) in the secondary circuit of the heat exchanger (9) is connected, so that the heat dissipation in case of falling below Input temperature (T _E ) can be stopped below a predetermined value.

27. Presentation rack according to one of claims 15 to 26, da¬ characterized in that at least one sensor (31) is provided for measuring the flow of the cooling liquid.

28, presentation rack according to one of claims 15 to 27, da¬ characterized in that the rear wall (3) has two shells to Bil¬ tion of a channel (10) for guiding the cooling air (K) is formed, wherein the cooling air (K) after leaving of the evaporator (8) from below into the channel (10) and through outlet openings

(12) above the floors (4) emerges.

29. Presentation rack according to claim 28, characterized in that the outlet openings (12) are arranged by juxtaposed tubes (16), for example with a honeycomb cross-section. are formed.

30. Presentation rack according to claim 28 or 29, characterized gekenn¬ characterized in that the outlet openings (12) are designed inclined.

31. Presentation shelf according to claim 30, characterized in that the inclination of the outlet openings (12) is adjustable.

32. Presentation shelf according to one of claims 28 to 31, da¬ characterized in that in the channel (10) means (13) for guiding the cooling air (K) are provided.

33. Presentation shelf according to one of claims 15 to 32, da¬ characterized in that the rear wall (3) has a heat insulation (11).

34. Presentation shelf according to one of claims 15 to 33, da¬ characterized in that lines (20) are provided for guiding the Kühl¬ liquid.

35. Presentation rack according to claim 34, characterized in that the lines (20) for guiding the cooling liquid have a heat insulation (21).

36. Presentation rack according to claim 34 or 35, characterized gekenn¬ characterized in that the cooling liquid lines (20) are provided with a connection (22).

37. Presentation shelf according to one of claims 15 to 36, da¬ characterized in that side walls (18, 19) are provided for lateral limitation.

38. Presentation shelf according to one of claims 15 to 37, da¬ characterized in that intermediate walls to create verschie¬ dener areas for storing various food (2) are provided.

39. Presentation shelf according to one of claims 15 to 38, da¬ characterized in that the at least one fan (7) and the at least one evaporator (8) is arranged at the bottom.

40. Presentation shelf according to claim 39, characterized in that the bottom of a removable tray for receiving condensate water is arranged.

41. Presentation shelf according to one of claims 15 to 40, da¬ characterized in that a sound insulation for the at least one fan (7) is provided.

42. Presentation shelf according to one of claims 15 to 41, da¬ characterized in that a lighting (15) is provided.