EP2033545B1 - Method and device for air conditioning a showcase - Google Patents

Abstract

The method involves emerging air from an interior space (8) of a cabinet (1) as an air stream (11). The air stream is conducted above a heat exchanger surface of a Peltier element (14), and into an air treating unit (16) which is made of temperature regulating material such as phase change material e.g. paraffin. The air from the inner space of the cabinet is cooled by the air treating unit, and is guided into the inner space of the cabinet. Humidity of the air stream is regulated by a unit which is made of humidity regulating material e.g. silicate-gel.

Description

introduction

The invention relates to a method for air conditioning a display case for the accommodation of objects that make high demands on the constancy of the air temperature, wherein air from an interior of the showcase led out as air flow, tempered by an air treatment unit with a temperature-regulating material, in particular a phase change material, in particular cooled, and then returned to the interior of the showcase. In addition, the invention relates to an apparatus for carrying out the method described above.

State of the art

For the purposes of the present application, a showcase is to be understood as a space bounded by glass panes or transparent plastic panes and by a floor or cover part of another material for storing and displaying objects, in particular in museums. The exhibits accommodated in such showcases typically place very high demands on the constancy of the temperature in the interior of the showcase.

Although the indoor climate in the premises of the museum is usually regulated by air conditioning systems, especially air conditioning systems, however, significantly higher requirements are required for the exhibits themselves in terms of indoor climate, so that in addition an intended for the showcase itself air conditioning system is required.

From the prior art, passive methods are known with which the air temperature can be controlled. For example, the air temperature can be obtained by arrangement of a P hase C hange M aterials are buffered in particular at a temperature rise (PCM), that is, passes in the course of temperature rise the PCM undergoes a phase change whereby the heat accumulated in the display cabinet is stored in the PCM and the interior of the showcase is cooled. In order to allow better control and regulation of the desired temperature, however, it makes sense to arrange the PCM in an air circuit operated by a fan. However, the performance of passive methods for air conditioning showcases is limited because only with the use of PCM only small temperature fluctuations can be compensated because the regeneration of the PCM is possible only by means of air with the ambient temperature.

As an example, this is the DE 10 2006 022 296 A1 or the EP-A-1 857 022 , which falls under Article 54 (3) EPC, which also describes a display case for housing articles with high requirements for the constancy of the air temperature. Air taken out of the interior of the showcase is tempered via an air treatment unit or regulated with respect to its moisture properties and returned to the interior of the showcase. The regulation of the moisture properties via a moisture-regulating material and the temperature control of the air via temperature-regulating material, such as phase change material.

As an example of an active method for air conditioning a showcase is at this point the DE 601 22 133 T2 from which a showcase with climate control system is known, which consists of a lower part and an exhibition chamber. The display chamber is connected to a hermetically sealed air circulation system having an air outlet for discharging air from the display chamber and an air inlet for supplying air into the display chamber. Between the air outlet and the air inlet, an electrically operated conditioning device is connected, which has means for heating or cooling the air or humidifying or dehumidifying it. In addition, to stabilize the environmental conditions in the exhibition chamber with respect to the humidity in the immediate vicinity of the exhibition chamber, a drawer arranged with hygroscopic material as silica gel or saline solution is filled and which is in atmospheric contact with the exhibition chamber.

However, active methods have the disadvantage that they cause a certain noise due to the use of fans, which is particularly disturbing in museums and often makes costly and costly soundproofing measures required.

Furthermore, in the case of decentralized systems in the course of cooling, the heat extracted from the showcase is released to a greater extent back into the ambient air of the museum, so that the museum is again burdened with heat.

Finally, it is still the DE 699 03 657 T2 However, this concerns a different technical field, namely a household refrigerator. The cooling of the refrigerator is achieved with a combination of Peltier elements with thermosiphon with phase changes from liquid to vapor.

task

Object of the present invention is to provide a decentralized method for air conditioning a display case, which is characterized by an optimized noise behavior and ensures a minimum heat load on the ambient air. It is another object of the present invention to provide an apparatus for carrying out this method.

solution

Based on a method of the type described above, this object is achieved in that the air flow is first passed over a heat exchanger surface of a Peltier element and then fed to the air treatment unit. The advantage of this method is the flexibility with regard to various temperature conditions present in the showcase.

The material properties of the PCM are chosen so that the melting point, ie the point of the phase transition, is in the range of the target temperature in the showcase. If there is a deviation of the existing temperature from the setpoint temperature in the showcase, the deviating air temperature of the airflow causes a phase change in the PCM. In the event that the existing temperature in the showcase is higher than the setpoint temperature, the PCM undergoes a phase change from solid to liquid so that heat energy is stored in the PCM and a cooling effect is achieved. On the other hand, the PCM goes through a phase change from liquid to solid, if the existing temperature in the showcase is below the target temperature, since the PCM stored heat energy is withdrawn. This creates a warming effect for the interior of the showcase.

If there is only a slight deviation between the existing temperature and the setpoint temperature of the showcase, a tempering of the interior climate of the showcase is possible solely by the PCM and activation of the Peltier element can be dispensed with. Although the air flow can still be performed by a non-activated heat exchanger surface of the Peltier element, however, arise when switched off Peltier element by this no noise emissions.

If the deviation between existing and desired temperature in the showcase reaches greater proportions, the tempering of the interior climate of the showcase can take place with increased performance by simple activation of the Peltier element, which is then used to support the cooling effect.

By means of the method according to the invention, it is thus possible to adapt the temperature control of the showcase to the prevailing climatic conditions, with noise emissions only being generated as required by the active air-conditioning and heat being generated for the surroundings of the showcase. The cooling capacity can thus be adapted to the heat loads acting on the display cabinet.

According to an advantageous embodiment of the method according to the invention, it is provided that the air flow is tempered during a first period by means of the air treatment unit with temperature-regulating material and the air flow is first tempered by means of the Peltier element during a later second period before passing through the air treatment unit with temperaturregulierendem Material is passed, which takes place in the second period in the temperature-regulating material by the tempered air flow, a phase change.

Consequently, in the first period only the PCM is used to control the temperature of the showcase, whereby it is gradually subjected to a phase change (loading process). If the entire PCM has a phase change dur h-run, it can not be used for air conditioning of the air flow and the use of the Peltier element is required. Since the temperature control of the air flow by means of Peltier element in front of the PCM, already tempered, for example, cooled air reaches the PCM, which in turn is regenerated e-riert, that is undergoes a u mended phase change. In addition to the actual function of the Peltier element, to cool the air flow, it therefore also fulfills the task of converting the PCM back into a state in which it can in turn be used for temperature control (discharge process).

The proposed method, for example, it is possible to make the cooling of a showcase during the day using PCM, which is regenerated at night by active cooling via a Peltier element and thus during the day is again able to absorb heat due to a renewed phase change from solid to liquid. The PCM makes it possible to shift the operation of active cooling into the night, so that the acoustic problem of the Peltier element during the day and therefore costly soundproofing measures can be eliminated. Furthermore, the heat output of the Peltier element is shifted to the night hours, whereby an additional temperature load of the museum does not occur during the day.

It is also advantageous if the air flow through the Peltier element is cooled to a temperature which is below the phase change temperature of the temperature-regulating material by a specific temperature difference. As a result, in addition to a latent cooling capacity, an additional proportion of sensitive cooling capacity can be built up and the efficiency of the method can be further increased. The aforementioned temperature difference may usefully be between 5 ° C and 10 ° C, if necessary also between 10 ° C and 20 ° C.

Advantageously, the humidity of the air stream is regulated according to an embodiment of the method by means of a unit with moisture-regulating material. Although showcases are produced for the display of exhibits with a relatively high density, nevertheless there is a certain exchange of air with the environment, which can cause fluctuations in the humidity. These are then balanced by means of the moisture-regulating material.

Furthermore, it is advantageous if the air flow is purified after exiting the interior of the showcase and before entering the interior of the showcase in each case by means of a filter, in particular a HEPA filter. The filter device prevents particles that might get into the air stream in the course of the air treatment from being transported into the showcase and possibly causing damage or spoiling the exhibit by depositing it. The moisture-regulating material may in particular be formed by silicate gel and / or a salt solution.

• mindestens einer Luftfördereinrichtung,
• einer damit verbundenen Ansaugleitung, die aus einem Innenraum der Vitrine herausgeführt ist, und
• einer damit verbundenen Druckleitung, die in den Innenraum der Vitrine mündet,

und eine Luftbehandlungseinheit mit einem temperaturregulierenden Material, insbesondere einem Phasenwechselmaterial, das in einem von der Luftfördereinrichtung geförderten Luftstrom angeordnet ist, gelöst, wobei in dem Luftstrom in Förderrichtung der geförderten Luft ein Peltier-Element vor der Luftbehandlungseinheit angeordnet ist. Die erfindungsgemäße Vorrichtung ermöglicht die Durchführung des weiter oben beschriebenen Verfahrens auf einfache Weise.According to the invention, the object is further represented by a showcase for the accommodation of objects that make high demands on the constancy of the air temperature of their environment, comprising an air conditioning module

• at least one air conveyor,
• a suction line connected thereto, which is led out of an interior of the showcase, and
• an associated pressure line, which opens into the interior of the showcase,

and an air treatment unit with a temperature-regulating material, in particular a phase change material, which is arranged in an air flow conveyed by the air conveyor, dissolved, wherein in the air flow in the conveying direction of the conveyed air, a Peltier element is arranged in front of the air treatment unit. The device according to the invention makes it possible to carry out the method described above in a simple manner.

In this case, the interior of the showcase can be connected via a closed air flow circuit with the air conditioning module, which is particularly advantageous in terms of a constant humidity.

In contrast, however, embodiments of the device may be preferred in which means for interrupting the air flow circuit are present.

In order to influence on the one hand, the humidity of the air flow and on the other to prevent the ingress of contaminants in the showcase, it may be advantageous to arrange in the air flow, a unit with moisture-regulating material and filters, preferably HEPA filter.

embodiment

The invention will be explained in more detail with reference to two embodiments of a showcase, which are illustrated in the drawings.

Figur 1:

eine schematische Darstellung einer ersten Vitrine und

Figur 2:

eine schematische Darstellung einer zweiten Vitrine.

It shows

FIG. 1:

a schematic representation of a first showcase and

FIG. 2:

a schematic representation of a second showcase.

In the FIG. 1 is a schematic representation of a display case 1 is shown, which has a limited by glass panes finished display part 2, which is provided with a lighting 3. Below the exhibition part 2 provided with a bottom 4, an air-conditioning module 5 is arranged, which is also indicated only schematically in the drawing figure.

The air conditioning module 5 has an air conveyor 6 in the form of a fan 7, which is operated by an electric motor, not shown. The fan 7 withdraws from the interior 8 of the display part 2 by means of a suction line 10 which is in communication therewith (via an outlet cross-section 9) and is initially cleaned by a filter 12. From the pressure side of the fan 7 is a pressure line 13, which leads to an electrically driven Peltier element 14, wherein the air flow 11 is passed so that it passes through a cold part 15 of the Peltier element 14.

The air stream 11 emerging from the Peltier element 14 is conducted via an air treatment unit 16, in which a temperature-regulating material, namely a phase change material (PCM), is arranged.

Starting from the air treatment unit 16, the pressure line 13 continues via a second filter 17 to open through an outlet cross section 18 in the interior 8 of the display part 2. This creates a closed air flow circuit.

The resulting on a warm side 19 of the Peltier element 14 heat is dissipated by means of an independent air flow 20 via a further fan 21 to the ambient air and does not enter the closed air flow circuit of the air conditioning module 5. The Peltier element 14 requires an electric power supply to function which is not shown in the figure.

Depending on the requirements, a unit with moisture-regulating material, not shown in the figure, can also be arranged in the closed airflow circuit Be able to compensate for any resulting moisture fluctuations in the display part 2.

The device described above has two different operating states, which are briefly explained below:

A first operating state, which is typically taken during the day, is characterized in that the Peltier element 14 is not active, that is, that the air flow 11 is guided only by the non-operating (passive) Peltier element 14. Accordingly, the heated part of the exhibition part 2 is withdrawn air, which penetrates virtually uncooled to the PCM. By appropriate selection of the material parameters of the temperature-regulating material (for example paraffin or salt hydrate) causes the heated air, which is above the phase change temperature of the PCM, an energy input into the temperature-regulating material, which is thereby melted, so undergoes a phase change. As a result, a cooling of the air flow 11 is achieved, which in turn is used for air conditioning of the display part 2 by this the cooled air is supplied.

In a second, typically occupied at night operating state, the Peltier element 14 is active and is used to cool the air flow 11. Accordingly, already cooled air passes to the air treatment unit 16, where it causes a reconsolidation, ie a regeneration of the PCM due to a suitable selection of the PCM phase change temperature. The reconsolidated PCM thus again has sufficient storage capacity to absorb heat and can in turn be used to air-condition display case 1 the next day.

Optionally, PCM can be cooled well below the required phase change temperature, thus building up an additional proportion of sensitive cooling capacity in addition to the latent one.

The device according to the invention is characterized by the possibility of adapting the temperature of the display case 1 in a simple manner to the climatic conditions in the display part 2 while using the active component only minimally. If there are only slight deviations between the existing temperature and the setpoint temperature in the showcase 1, the temperature control is achieved solely by the PCM. If necessary, a regeneration of the PCM by briefly switching on the Peltier element 14 take place, which causes active cooling of the air flow 11, which causes a reverse phase change from liquid to solid when passing the PCM. Thus, the PCM is then again in a state in which it can be used again for cooling the air flow 11.

By the device according to the invention, it is possible to make the cooling of a showcase 1 over the day only with the help of the PCM, so that there is no noise pollution during museum operation, nor an additional temperature load of the museum rooms arises. An active cooling, which is also used for the regeneration of the PCM, takes place only at night, so that both the resulting noise and the heat generated during operation of the Peltier element 14 is not a disturbance for the museum operation. Elaborate soundproofing measures on the display case 1 can thus be dispensed with.

The in the FIG. 2 showcase 1 differs from that in the FIG. 1 shown showcase 1 only in the arrangement of two flaps 22, 23 in the intake manifold 10 and also two flaps 24, 25 in the pressure line 13, wherein the flaps 22, 23 of the suction pipe 10 between the display case 1 and the filter 12 are arranged and the Flaps 24, 25 of the pressure line 13 between the air treatment unit 16 and the second filter 17th

If the flaps 23, 24 are in a blocking position and the flaps 22, 25 are in an open position, the operation of the air-conditioning module differs 5 according to the FIG. 2 not from that of the air conditioning module 5 according to FIG. 1. The air flow 11 is conditioned in a closed air flow circuit.

However, according to the design of the air conditioning module according to the invention, it is possible to completely close the interior of the display part 2 by locking the shutters 22 and 25 so that air circulation in the area of the display part 2 is prevented. At the same time, the flaps 23 and 24 can be opened, whereby air is sucked from the environment of the display case 1, which in turn is used for regeneration of the PCM in the Luftb e-treatment unit 16. In this way, there is the advantage that fluctuations in the air temperature behind the air treatment unit 16, which may arise through the regeneration cycle of the PCM, can not affect the display part 2 of the display case 1 or the Ausste I-pieces in it. Since the external temperature load of the display part 2 as a result of lighting 3 or people at night is almost zero and the display part then requires no air conditioning for a certain time, the aforementioned type of air conditioning is particularly suitable for a regeneration of the PCM at night.

LIST OF REFERENCE NUMBERS

1

Showcase

2

exhibition part

3

lighting

4

ground

5

Cooling module

6

Air conveyor

7

fan

8th

inner space

9

Outlet cross section

10

suction

11

airflow

12

filter

13

pressure line

14

Peltier element

15

Cold part

16

Air handling unit

17

Second filter

18

Outlet cross section

19

Warm side

20

airflow

21

fan

22 to 25

flap

Claims (10)

1. A method for air-conditioning a showcase (1) for accommodating objects which have high requirements for a uniform air temperature, air being guided out of the internal space (8) of the showcase (1) as an air stream (11), temperature-controlled, in particular cooled, by an air treatment unit (16) comprising a temperature-controlling material, in particular a phase change material, and then guided again into the internal space (8) of the showcase (1), the air stream (11) initially being passed over a heat-exchanging surface of a peltier element (14) and then passed to the air treatment unit (16).
2. The method according to Claim 1, characterised in that during a first time period the air stream (11) is temperature-controlled, in particular cooled, by means of the air treatment unit (16) comprising temperature-controlling material, and during a subsequent second time period the air stream (11) is initially temperature-controlled, in particular cooled, by means of the peltier element (14) before it is passed through the air treatment unit (16) comprising temperature-controlling material, whereby in the second time period a phase change takes place in the temperature-controlling material through the temperature-controlled air stream (11).
3. The method according to one of the preceding claims, characterised in that the air stream (11) is cooled via the peltier element (14) to a temperature which is below the phase change temperature of the temperature-controlling material by a specific temperature difference.
4. The method according to one of the preceding claims, characterised in that the humidity of the air stream (11) is controlled by means of a unit comprising humidity-controlling material.
5. The method according to one of the preceding claims, characterised in that after emerging from the internal space (8) of the showcase (1) and before entering the internal space (8) of the showcase (1), the air stream (11) is cleaned in each case by means of a filter (12, 17), in particular a HEPA filter.
6. A showcase (1) for accommodating objects which have high requirements for a uniform temperature of their surroundings, comprising an air-conditioning module (5) with

   - at least one air conveying device (6),

   - a suction line (10) connected thereto, which is guided out of an internal space (8) of the showcase (1), and

   - a pressure line (13) connected thereto which discharges into the internal space (8) of the showcase (1),

   and an air treatment unit (16) comprising a temperature-controlling material, in particular a phase change material, which is arranged in an air stream (11) conveyed by the air conveying device (6), a peltier element (14) being arranged in the air stream (11) in the direction of conveyance of the conveyed air, upstream of the air treatment unit (16).
7. The showcase (1) according to Claim 5, characterised in that the internal space (8) of the showcase (1) is connected via a closed air stream circuit to the air-conditioning module (5).
8. The showcase (1) according to Claim 7, characterised by means by which the air stream circuit may be interrupted.
9. The showcase (1) according to one of Claims 5 to 7, characterised in that a unit comprising humidity-controlling material is arranged in the air stream (11).
10. The showcase (1) according to one of Claims 5 to 8, characterised in that a filter (12, 17), preferably a HEPA filter, is arranged upstream and/or downstream of the air treatment unit (16) in the air stream (11) in the direction of conveyance of the conveyed air.

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