WO2009132639A2

WO2009132639A2 - Housing

Info

Publication number: WO2009132639A2
Application number: PCT/DE2009/000613
Authority: WO
Inventors: Jose Manuel Fernandez Martin
Original assignee: Eads Deutschland Gmbh
Priority date: 2008-05-02
Filing date: 2009-04-29
Publication date: 2009-11-05
Also published as: WO2009132639A4; DE102008022000A1; WO2009132639A3; WO2009132639A9

Abstract

The invention relates to a cupboard-type housing for receiving heat-generating, especially electrical and/or electronic structural units, an inner region of said housing being enclosed by walls and a cover. The walls are at least partially double, with an outer wall and an inner wall, and an intermediate space between the outer wall and the inner wall. The cover closes the inner region at the top and is laterally connected to the inner wall of the double wall. The inner wall receives at least part of the heat generated by the structural units from the inner region. The housing comprises a first roof which grips above the upwardly open intermediate space of the double wall and forms a closure with the associated outer wall. At least one ventilator is provided in the first roof for cooling the inner region by producing an air flow through the intermediate space. The intermediate space is open at the top, where it is connected to the at least one ventilator, and at the bottom, where it is connected with the surroundings of the housing. A thermal insulation material having a closed cell structure is applied to the surface of the outer wall, facing the inner wall.

Description

casing

The invention relates to a housing according to the preamble of patent claim 1.

For the shielded against climatic effects and with respect to the emission of electromagnetic interference accommodation of electrical and / or electronic devices and modules of telecommunications, traffic control, high voltage and medium voltage engineering, especially in outdoor areas, different cabinet-like housing are used in the prior art. Such cabinet type enclosures are e.g. from DE U 295 19 260 and EP 1 002 352 B1.

Such mostly rectangular housing enclose with metallic walls on all sides an interior in which the devices are housed. Often, lockable doors are provided for easy access during installation, maintenance, and repair on the front of the housing. In enclosures for outdoor use, a roof is usually additionally arranged on the upper side, which protects the housing against rain and sunlight.

The protective function, in particular also the electromagnetic shielding function of the housing, entails that the interior space is sealed relatively tight with respect to the surrounding exterior space by means of suitable seals. This also has the advantage that the devices and assemblies located in the housing are largely protected from dust and moisture, but also insects (termites) or the like., Protected. If the devices and assemblies generate heat during their operation, this heat is transferred from the heated air in the interior and / or by heat radiation on the walls of the housing and discharged from the outside by air convection and / or thermal radiation to the environment. On the other hand, it is also known to arrange special refrigeration units or air conditioning units inside such a housing for heat dissipation, but consume such refrigeration units or air conditioners relatively much power. However, such high power consumption is intolerable in those cases where the devices and assemblies housed in the housing need to be supplied by a local battery as part of an emergency power supply. In addition, a high power consumption for economic and ecological reasons is no longer compatible with modern technology.

The heat dissipation from the outside by air convection and / or heat radiation to the environment is problematic when a lot of heat is generated inside the housing, or if the housing is additionally heated from the outside by strong sunlight and high outside temperatures. Special (reflective) coatings of the outer surfaces of the housing can indeed reduce the influence of solar radiation, but the negative consequences of a strong heat inside can not be effectively prevented. The heat dissipation from the interior deteriorates, however, if double walled walls are used instead of simple walls for reasons of stability, because the heat transfer from the inside to the outside is hindered in this case by additional interfaces. A good heat dissipation from the interior can still be achieved by sucking a cooling air flow from bottom to top through the interior of the housing (provided with ventilation openings) by means of a fan arranged, for example, on the top of the housing. However, with this type of forced cooling, the advantageous conclusion of the interior compared to the outside space must be abandoned.

EP 1 002 352 B1 describes a housing which uses the double walls of the walls in order to dissipate the heat from the interior. The double-walled walls are made of vertically arranged aluminum Hollow profiles assembled. The disadvantage here is the resulting between the inner and outer wall thermal bridge.

The heat dissipation is carried out by air through the spaces between the inner wall and outer wall and the use of a top roof, an intermediate roof and mounted in the intermediate roof fans for generating an air flow through the interstices. Through the intermediate space formed between the intermediate roof and the top roof, the air extracted by the fans is forced out laterally and downwards out of openings into the environment. The

Flow is directed in the area of the walls from bottom to top, whereby the natural convection flow is supported. In the area of the intermediate roof, however, the flow is horizontal and directed in the area of the subsequent openings from top to bottom. In these areas, the natural convection flow is severely hampered, requiring more suction power from the fans.

From US 6,088,225 A1 a generic housing with a double-walled side wall is known. In this case, an insulating material in the form of a polystyrene or polyethane foam or in the form of glass wool is applied to the inner wall facing surface of the outer wall. However, this arrangement is disadvantageous in that it can come to detachment of the insulating material from the side wall.

The object of the invention is to provide a comparison with the prior art improved housing, in which the removal of the heat from the interior compared to the prior art is made more efficient and energy-efficient.

This object is achieved in a housing of the known type by the features of claim 1. The essence of the invention is the thermal Isolation of the gap and the inner wall to improve against the strongly heated outer surface under sunlight.

According to the invention, an insulating material with a closed cell structure is attached to the inner wall facing surface of the outer wall. The thickness of the insulating material is suitably between 2 and 4 cm and the coefficient of thermal conductivity of the insulating material is advantageously less than 0.03 W / mK. In a particular embodiment, the insulating material is formed so that the thickness of the region of the housing bottom to the top, ie in the direction of the building roof increases. As a result, the cross section of the gap between the outer wall and the inner wall is reduced to the same extent. By this measure, a kind of chimney effect is effected, which in turn causes the air can flow faster and more uniformly in the intermediate space. The more uniform (laminar) flow ensures that the air can better absorb the heat released by the inner wall.

The closed cell structure of the insulation material ensures that the material is not damaged by the air humidity in the gap. In addition, the closed cell structure prevents the insulating material from absorbing the water in the air, thereby deteriorating the insulating properties. As the insulating material extruded polystyrene can be used in a particular embodiment of the invention.

Between the inner wall and the outer wall there is a spacer designed as a thermal insulator. This spacer is thus suitable for thermally decoupling the inner wall from the outer wall. In contrast to the aluminum cavity profiles described in EP 1 002 352 B1, where heat transfer between the inner and outer walls is caused by the cavity profiles themselves, in the invention only a very small heat transfer of less occurs between the inner and the outer wall than 1 W / m ² K instead. A heat transfer supply takes place in the housing according to the invention exclusively between the inner wall and the air located in the intermediate space.

In an advantageous embodiment of the invention, a second roof is present, which is mounted on the first roof. The second roof is mounted at a predeterminable angle to the first roof. On the second roof solar modules are mounted in a preferred embodiment.

The use of a second roof equipped with solar modules offers 3 decisive advantages:

In addition to generating electricity for housed in the housing electrical components, the proposed solar modules serve as "active cooling". Known solar cells convert about 15-25% of the incident solar radiation into electrical energy. The incident on the outer walls and the roof of the housing solar energy is thus reduced by these 15-25%, resulting in a lower thermal heating of the corresponding surfaces result. In contrast to the housing known from EP 1 002 352, the shaded areas must therefore be cooled with a lower energy consumption in the invention. The third advantage is that the second roof continues to serve the "passive cooling" by shading the housing, thus supporting the cooling of the interior. To improve this shading effect, the second roof extends beyond the dimensions of the first roof. As a result, the shadowing of the side walls is also favored depending on the position of the sun. The solar modules are expediently 48VDC photovoltaic solar modules.

Depending on the location of the enclosure, select an angle of approximately 90% of the latitude of the current location of the enclosure, ensuring the maximum annual energy yield of the solar panels. On the other hand should be off

Self-cleaning reasons, these angles should not be less than 10 ° -12 °, otherwise it takes Pollution over time, whereby the energy yield of the solar modules decreases. Conveniently, the angle at which the second roof is mounted on the first roof is between 10 ° and 50 °.

By arranged in the first roof fans, the solar modules are acted upon from the back with an air flow from the space between the outer and inner walls of the housing. The temperature of this air flow is usually lower than the working temperature of the solar modules under full solar radiation, which is usually between 45 ⁰ C to 50 ⁰ C and higher. It is known, however, that the solar modules have an efficacy of 15-25% only at a temperature of about 20 ⁰ C. As the temperature of the solar modules increases, the efficiency of the solar modules decreases. The back cooling of the solar modules reduces the working temperature of the solar modules. As a result, the efficiency is somewhat improved, unlike uncooled solar modules.

In a further embodiment of the invention, each fan is connected to a Bi- metal switch, wherein the bi-metal switch mounted in the interior of the surface of a heat-generating assembly. The bi-metal switch allows the fan to be controlled depending on the temperature of the heat-generating unit. As a result, the power consumption of the fans can be controlled via the temperature of the units. If the outside temperatures decrease, e.g. At night, it is not or only partially necessary to operate the fans. This saves additional electrical energy.

In addition, a switched-off, ie non-rotating, fan makes it difficult for air to flow in the intermediate space due to convection. Thus, the air in the air gap does not move or only slightly, whereby the air in the space at low outside temperatures serves as additional insulation for the interior. In other words, with high outside temperatures and high levels of solar radiation, with the fans in operation, airflow will be in the space Prevents the inner walls surrounding the units from being overheated and thus increasing the temperature in the interior beyond the permissible operating temperatures of the units. At low outside temperatures, where the fans are not in operation, the gap prevents the interior from overcooling due to the fact that air flow is prevented. This will automatically regulate the indoor temperature of the interior even in places with extreme fluctuations in the outside temperature (eg higher elevations, deserts, etc).

The fans work expediently with a DC voltage of 48VDC. Furthermore, the fans are dimensioned so that the least possible power is consumed in order to generate the necessary for cooling airflow. Suitably, each fan with as little electrical power consumption as possible should be able to move the largest possible amount of air, for example, each fan about 1000m ³ / h at about 50 W. The required amount of ventilation and thus the selection of the respective fan is at the dissipated heat taking into account the heat capacity the air determines.

In a further embodiment, with two or more fans, the fans can be actuated at different predeterminable temperatures on the surfaces of the heat-generating units. This also electricity can be saved.

The invention will be explained in more detail with reference to figures. 1 shows a schematic longitudinal section of an embodiment of a housing according to the invention,

Fig. 2 is a schematic plan view of an embodiment of a housing according to the invention. In Fig. 1, an embodiment of a housing according to the invention is shown in the schematic longitudinal section. Fig. 2 shows a schematic plan view of an embodiment of a housing according to the invention. The housing 1 encloses with walls, to which the side walls 2, 3 and the lid 7b belong, an interior space 4, in which the example indicated heat generating units 5a, 5b housed. The interior is completed on the bottom by a floor panel. The housing 1 is ideally arranged elevated on a pedestal (not shown) so that air from below has free access to the undersides of the walls 2, 3.

Suitably, the housing 1 comprises two side walls 2,3, a front wall 12 and a rear wall 13. In addition, the housing 1 comprises a bottom plate and a lid 7b. All walls 2, 3, 12, 13 are expediently double-walled and consist of an inner wall 2b, 3b and an outer wall 2a, 3a between which in each case a gap 2c, 3c remains. This intermediate space 2c, 3c serves to dissipate heat from the interior 4.

The outer wall 2a, 3a is connected to the inner wall 2b, 3b via spacers 9. These spacers 9 are expediently designed as a bolt. In order to prevent heat transfer between the walls, the bolts are advantageously made of a low thermal conductivity material. In addition, a thermal insulation layer 10 is attached to the inside of this outer wall 2a, 3a in order not to emit the solar radiation heat to the gaps 2c, 3c.

Through the interspaces 2c, 3c of the walls 2, 3, an air flow is now sent for cooling, preferably from bottom to top, as indicated in FIG. 1 by the flow lines provided with arrows. The air is sucked in from the environment of the housing 1 on the underside of the walls 2, 3 and exits from the walls 2, 3 at the top again. The bottom of the walls 2, 3 is suitably provided with insect screens. When flowing through the intermediate spaces 2, 3, the air streams absorb heat from the inner walls 2b, 3b and transport this heat into the environment. To generate the cooling air flow fans 6 are provided, which are arranged lying flat in a first roof 7a. The first roof 7, which consists for example of a metal sheet, engages over the upwardly open intermediate spaces 2c, 3c of the double-walled walls 2, 3 and terminates with the associated outer wall 2a or 3a of the walls 2, 3. As a result, a flat gap 7c is formed between the cover 7b and the first roof 7a, in which the air streams from the spaces 2c, 3c of the walls 2, 3 can flow and are sucked from there through the fans 6a, 6b upwards. The fans 6 (and the entire housing 1) are protected at the top by a second roof 8, which is arranged at a predeterminable angle above the first roof 7. On the second roof 8 expediently solar modules are arranged (not shown). By the fans 6a, 6b, the air from the gap 2c, 3c, 7c in the direction (flow arrows in Fig. 1) of the underside 8a of the second roof 8 is pressed. This causes a cooling of the underside 8a of the second roof 8, whereby the operating temperature of the arranged on the second roof 8 solar modules is reduced and thereby, as already explained above, the efficiency of the solar modules is slightly increased. The solar modules can also form the roof 8 itself in a particular embodiment of the invention. The projection of the second roof 8 on the first roof is suitably larger. As a result, an additional shading of the side walls is achieved.

Due to the described guidance of the cooling air streams in the interspaces 2c, 3c of the double-walled walls 2, 3 and the intermediate space above the cover 7b, an external cooling circuit between the environment and inner walls 2b, 3b is established, which is completely separated from the interior 4. The heat dissipation takes place by convection and / or forced cooling, without the cooling air must be passed through the interior 4. The encapsulation of the interior 4, which is particularly advantageous for reasons of shielding and tightness against dust and moisture, therefore need not be abandoned in this type of cooling. The cooling tion of the system depends on various parameters such as the flow rate of the fans 5a, 5b, the cross-section and flow resistance of the ventilation ducts, the flow velocity, the heat transfer between inner walls 2b, 3b and air flow. In practice, a design of the system has been proven in which the air inlet speed at the bottom of the walls 2, 3 is such that the air in the intermediate space 2c, 3c moves substantially laminarly (small Reynolds number, but at the limit Turbulent movement). In our application about 0.5 m / s. This achieves optimum heat exchange between inner wall 2b, 3b and air. If the flow velocities are too high, as indicated for example in EP 1 002 352 B1 as 2 m / s, turbulence develops in the intermediate space. These turbulences have a negative effect on the heat exchange between inner wall 2b, 3b and air.

The heat transfer to the inner walls 2b, 3b is optimized by cooling fins 11 on the inner walls 2b, 3b. Expediently, further means in the form of heat pipes (not shown) for heat transfer between cover 7b and the air in the intermediate space can be mounted on top of cover 7b.

With regard to the fans 5 a, 5 b, it is advantageous in view of the desired low energy consumption to use types of fans with which a maximum air volume per hour, for example about 1000 m ³ / h per fan can be moved at given cross sections of the spaces 2c, 3c, 7c , With as small as possible power consumption of the fans 5a, 5b, eg 5OW.

The construction of the double-walled walls 2, 3 takes place in that an outer wall 2a, 3a arranged parallel to the inner wall 2b, 3b and secured by means of spacers 9 to this, for example, welded or screwed. The spacers 9 are made of a non-thermally conductive material. Thus, the spacers serve as insulation between inner wall 2b, 3b and outer wall 2a, 3a, so that no heat transfer between the inner wall 2b, 3b and the outer wall 2a, 3a takes place. In other words, the heat conduction coefficient of the spacers should be less than the heat conduction coefficient of the air in the gap 2c, 3c.

On the inner wall 2b, 3b side facing the outer wall 2a, 3b, an insulating layer 10 is applied according to the invention. This insulating layer 10 is characterized by a very low coefficient of thermal conduction of λ <0.04 W / mK, preferably λ = 0.025 W / mK. The insulation layer 10 is further characterized by a closed cell structure, which ensures that due to the humidity in the space 2c, 3c, the insulation material is not damaged. Appropriately, extruded polystyrene is used as insulation material. The thickness of the insulating material 10 is given as 2 cm - 4 cm. The insulating layer minimizes the transmission component of the external radiation, ie the radiation which strikes the housing 1. The transmission heat is thus converted into absorption heat in the outer wall 2a, 3a. According to the Stephan-Boltzmann law, this heat is radiated corresponding to T ⁴ to the environment, where T corresponds to the surface temperature of the outer wall 2a, 3a.

At the heat-generating assemblies 5a, 5b mechanical bi- metal switches 14a, 14b are mounted, which are each connected to a fan 6a, 6b. By means of the mechanical bi-metal switches 14a, 14b, the fans 6a, 6b can be individually controlled in dependence on the surface temperature of the heat-generating units 5a, 5b. If, for example, the surface temperature of a structural unit 5a, 5b falls below a predetermined temperature, operation of the fan 6a, 6b is not necessary, so that the respective fan 6a, 6b is switched off via the respective bi-metal switch 14a, 14b. This additionally saves electricity. In this case, in one embodiment of the invention, it is possible for the mechanical bi-metal switches 14a, 14b to operate at different temperatures, ie It is achieved that the fans 6a, 6b start at different temperatures. This makes it possible to adjust the air flow within the intermediate spaces 2c, 3c, 7c in accordance with the evolution of heat in the interior 4.

Claims

claims

1. cabinet-like housing for receiving heat-generating, in particular electrical and / or electronic, structural units (5a, 5b), in which housing (1) an interior (4) of walls (2, 3) and a cover (7b) is enclosed wherein the walls (2, 3) at least partially double-walled with an outer wall (2a, 3a) and an inner wall (2b, 3b) and between the outer wall (2a, 3a) and inner wall (2b, 3b) arranged intermediate space (2c, 3c ) are formed and the lid (7b) closes the interior (4) towards the top and laterally to the inner wall (2b, 3b) of the double-walled wall, wherein the inner wall (2b, 3b, 7b) from the interior (4) at least receiving a portion of the heat generated by the assemblies (5a, 5b), the housing (1) having a first roof (7a) which engages over the upwardly open space (2c, 3c) of the double-walled wall and the associated outer wall (2a, 3a) closes, wherein for cooling the interior (4) by produc- g of an air flow through the intermediate space (2c, 3c) one or more fans (6a, 6b) are provided, which in the first roof (7a) are arranged, wherein the intermediate space (2c, 3c) is open at the top and there with the one or more fans (6a, 6b) is in communication and is open at the bottom and there communicates with the environment of the housing, wherein on the inner wall (2b, 3b) facing surface of the outer wall (2a, 3a) a thermal Insulation material (10) is applied, characterized in that the thermal insulation material (10) has a closed cell structure.

2. Housing according to claim 1, characterized in that the thickness of the thermal insulation material (10) upwards, in the direction of first roof (7a) increases, so that the cross section of the space

(2c, 3c) decreases in this direction.

3. Housing according to one of the preceding claims, characterized in that on the inner wall (2b, 3b) facing surface of the outer wall

(2a, 3a) attached insulating material (10) is an extruded polystyrene, for example.

4. Housing according to one of the preceding claims, characterized in that between the outer wall (2a, 3a) and the inner wall (2b, 3b) designed as a thermal insulator spacer (9) is present.

5. Housing according to one of the preceding claims, characterized in that a second roof (8) is provided which is arranged on the first roof (7a) at a predeterminable angle to the first roof and which comprises solar modules, the active cooling of the interior (4) by converting solar energy into electrical energy, the passive cooling by shading the housing and the power supply in the interior (4) arranged electrical and / or electronic, building units (5a, 5b) are used.

6. Housing according to claim 5, characterized in that the angle at which the second roof (8) on the first roof (7 a) is arranged between 10 ° and 80 ° or about 90% of the geographical latitude of the location of the housing (1 ) is.

7. Housing according to one of claims 5 or 6, characterized in that the second roof (8) beyond the dimensions of the first roof (7 a) protrudes.

8. Housing according to one of the preceding claims, characterized in that each fan (6a, 6b) with a mechanical bi-metal switch (14a, 14b) is connected, which in the interior (4) on the surface of a heat-generating assembly (5a, 5b ), wherein the bi-metal switch (14a, 14b) allows a temperature-dependent control of the respective fan (6a, 6b).

9. Housing according to claim 8, characterized in that at two and more fans (6a, 6b) each fan (6a, 6b) is driven at a temperature individually for the respective fan (6a, 6b) predetermined temperature.

10. Housing according to one of the preceding claims, characterized in that the housing (1) comprises two side walls (2, 3), a front wall and a rear wall and that all walls are double-walled and flows through the cooling air flow.

11. Housing according to one of the preceding claims, characterized in that the inner walls (2b, 3b) of the double-walled walls and / or the cover (7b) comprise cooling ribs (11) for enlarging the heat transfer surface.