DE10218115B4 - Cooling device, in particular for the air conditioning of small appliances and / or operating units - Google Patents

Abstract

Cooling device with Peltier elements, which have a hot and a cold side, on each of which a heat exchanger is provided, as well as with an at least two-part housing, in particular for the air conditioning of small appliances and / or operating units,
characterized in that
a support plate (9) symmetrically grouped recesses, in which Peltier elements (10) are arranged, wherein each of the heat exchangers (11) of the hot side on a first support plate side and the heat exchanger (12) of the cold side on the opposite, second support plate side are located,
on the first support plate side between two of the heat exchanger (11) a fan (13) is arranged to dissipate warm air to the environment, on the second support plate side at the intersection of two, each diagonally juxtaposed heat exchangers, a fan (14) is arranged, a first Housing part (4) the second support plate side including heat exchanger and fan (14) covers, wherein the first housing part (4) in the suction region of the fan (14) suction openings (16) and laterally opposite outlet openings (6), all to be ...

Description

The The invention relates to a cooling device with Peltier elements according to the generic term of claim 1

Small refrigerators of the series VIP of the company Rittal, HB31, p.595, belong to the state of the art. such equipment are specially designed for cooling of operating housings provided and there due to system-related lower heat loads designed. Such cooling devices have an assembly, the left or right side arranged condenser to take account of various installation situations. The disadvantage of such known devices is in addition to the unfavorable Luftwegführung in danger of falling below the dew point with the consequence of unwanted Condensation, under certain circumstances also on the sensitive electronic components of the to be cooled Unit.

Out In an internal state of the art, a cooling device for air-conditioning of control cabinets is known, which uses Peltier elements. The Peltier elements point Heat sink on, which are forced ventilated on both the warm and the cold side. The cooling unit is intended for increase the effectiveness operated in at least three different cooling modes, wherein for each single mode the interconnection of the Peltier elements with each other changed becomes. At lower ambient temperatures, a decoupled thermal connection provided between the Peltier elements be an air / air heat exchanger without Use of the thermoelectric effect to form.

Farther is proposed in addition a compressor cooling provide for a further cooling capacity adjustment based on the respective to be cooled Device to reach.

Either the extra Compressor cooling as also the decoupled thermal connection on the basis of a Liquid circulation However, with the pump and the valve, they provide clear advantages Thermoelek cal cooler means Peltier elements again canceled out and increase the costs not insignificant.

From the DE 200 13 775 U1 a Peltier element is known, which is thermally conductively connected both on the cold side and on the hot side, each with a heat exchanger and wherein one fan is associated with a heat exchanger.

Out The above, it is therefore an object of the invention, a further developed Cooling device, in particular for the air conditioning of small appliances and / or operating units which operates on a thermoelectric basis and for this purpose on Peltier elements recourse. The cooling device should be inexpensive be produced and rely on standard assemblies, starting out from a basic construction by simply increasing the number of prefabricated ones Peltier elements and adding more fans on the particular application, i. the necessary useful cooling capacity to be reacted can.

The solution The object of the invention is achieved with a cooling device according to the features of Patent claim 1, with a method for operating a cooling device according to claim 8 and a control device for operating a cooling device according to claim 10, wherein the dependent claims expedient embodiments and represent further education.

Accordingly, there is the basic idea of the invention therein, symmetrically grouped on a support plate Arrange Peltier elements so that in each case the heat sink or heat exchangers the warm one to the first, i. Plate top and those of the cold ones Side to the second, i. Directed plate underside. For this purpose points the support plate recesses according to the shape and number of the Peltier elements.

On the top of the plate are each at least between two of the heat exchanger Fan arranged to dissipate warm air to the environment, i. an external circuit to build.

On the underside of each plate at the intersection of two diagonally opposite arranged heat exchanger pairs is a fan, in particular radial fans located. about a lower housing part, covering the underside of the plate including heat exchanger and radial fan, is by means of appropriate openings Air from the to be cooled Device or to be cooled Device sucked and by means of laterally opposite outlet openings chilled the corresponding device fed again.

Of the Symmetrical structure gives in the outer circuit a central Intake of the ambient air as well as in the inner circuit. An air short is with it minimized. The opposite, on the long side extending exhaust openings, the preferred over the entire device width rich, take care of a plane outflow and thus very even distribution the cooling air in the operating housing, what the formation of hot springs effectively prevented.

Have the heat exchanger as a heat sink preferably fins or cooling plates, which have such a rib distance that conventional dirt particles are blown clean due to the high air velocities and the distances through the cooling device, without causing a deposit.

by virtue of the maintainable low temperature difference between cooling air and Heat sink surface of maximum 5 ° C works the cooling device according to the invention in an area where no condensate forms in the device can, so that drip pans or the like become superfluous.

Of the liquid-free Structure of the thermoelectric cooling leads to a location-independent Operation. The structure with few moving parts without piping allows a vibration-proof, very quiet operation, in particular compared to cooling equipment, which work on an evaporator basis.

According to the invention the Peltier elements are clocked or operated purely current-controlled, a corresponding adaptation to the respective cooling task to achieve in a simple manner. Another power regulation does not go through in contrast to the prior art thermal decoupling made, but also on the flow velocities in each circuit, i.e. achieved by adjusting the speed of the fan.

On This way can be conscious the temperature gradient between warm and cold side are affected, to work in the optimal range of action of the Peltier elements, so that the Total energy balance of the cooling device improved.

Of the or the fans located on the top of the disk, i. the fans of warm side can be axial fans. There is the possibility the air alone over the side surfaces of the housing to let in and out again.

Of course, there is but also the possibility for the warm side radial fan be used to suck the air centrally axially and radially over the cooling fins the heat sink too to guide the respective outlet or exhaust openings.

Prefers is always between two opposite Heat sinks of warm side of such a radial fan arranged, as mentioned, the heat sink in flow direction lying cooling fins or sheets.

The upper housing part has suction openings in the respective suction area of the radial fan (s) on and the air outlets are symmetrically placed on both sides in the upper housing part. Prefers Both the support plate and the housing parts have a square or rectangular shape, with the Peltier elements symmetrically distributed uniformly attached to the support plate in the recesses provided there are.

The exhaust openings at least the cold side extend at a rectangular Embodiment over the Long sides, in which case the cooling fins or sheets extend substantially parallel to the narrow side.

The Support plate decouples the warm from the cold side of the device and may have insulating properties.

The casing is especially as a flat housing formed, wherein the useful cooling air flow in essentially vertical as well as the waste heat-cooling air flow in the essentially parallel to the housing upper or -unterseite runs.

to Power control of the Peltier elements can be applied to a MOSFET circuit be resorted to. in principle are in such a scheme all Peltier elements in Series switched. At the moment when increased cooling becomes necessary used fast switching MOSFETs with variable pulse width, preferred operated in the range of 10% to 100%.

The such clocks is done so that all Peltier elements are controlled in parallel, so that for the duration the pulse width the full cooling capacity is delivered.

In the pauses in the pulse are prevented by the series connection of the Peltier elements an unwanted inversion the heat flow, i.e. it occurs the effect of a kind of check valve. Between series-connected Peltier elements Schottky diodes with low power dissipation are switched to to prevent that for the duration the control enters a short circuit. Depending on the characteristics of the Peltier elements will be an optimal pulse rate set, for example, in the range of substantially 10 kHz can be.

at an embodiment The invention is the housing top with vents provided, preferably located in the corner areas openings to operate a concealed attachment device for the entire device and / or lead to preferred screw, with the help of a Disassembly of the cooling device possible becomes.

The spaces between the heat sinks of the Peltier elements, these preferred on the cold Sei te may serve to accommodate the control electronics for the power control of the Peltier elements and have corresponding contact or connector to effect an electrical connection via the device to be cooled or the corresponding control unit to be cooled. Any external connection points with separate power supply can therefore be omitted.

Around especially with control housings with liquid crystal displays to ensure the function of such display devices it is possible, briefly by reversing the current direction on the otherwise cold side to supply heat to the operating housing, without that one separate heating is required.

The Invention will be described below with reference to an embodiment and below With the help of figures closer explained become.

For this demonstrate:

1a C) a first embodiment of the cooling device with housing top and bottom side and provided there Lufteinritts- and -austrittsöffnungen and a perspective view;

2a -D) an embodiment of another housing upper part for a cooling device with greater useful cooling capacity in plan view. Settlement, perspective view and view of the bottom as well

3 a schematic representation of a cross section through a cooling device with flat housing and recognizable external and internal circulation.

In the 1a such as 2a is a plan view of an upper housing part 1 a cooling device according to embodiment shown, wherein the upper housing part 1 on two sides opposite flow openings 2 available. Furthermore, the upper housing part 1 in the respective suction region of the (not shown) fan suction openings 3 on. When using centrifugal fans is on the suction openings 3 Sucked in ambient air, which then passed over the respective heat sink at the lateral flow openings 2 exit.

1b is the representation of an exemplary underside of the cooling device or a lower housing part 4 , At the intersection of two diagonally opposite heatsink pairs 5 is a (not shown) radial fan located, wherein the lower housing part 4 In the suction area of this radial fan suction openings 16 for the inner circuit of the device to be cooled. On the side opposite are exhaust openings 6 present, which are guided over substantially the entire width of the device and allow a flat outflow and thus very even distribution of cooling air in the (not shown) control housing.

The perspective view of the 1c and 2c discloses an embodiment of the upper housing part with two laterally chamfered corners 7 , In these corners 7 are holes 8th formed, the access to a mounting option both the housing top 1 as well as to secure the entire cooling device to a control housing, not shown, or similar device.

In the embodiment according to 1a -C) is assumed by two fans for the warm outside and a fan for the cooling side of the inner circuit. The cooling device after 2a -D) uses four fans for the external circuit and, for example, two fans for the internal circuit. The 2 B ) represents a settlement of the upper housing part, as shown in the 2a ) in plan view, in the 2d ) in view of the bottom and in the 2c ) is shown in perspective.

In the schematic representation after 3 is the support plate 9 recognizable, which the Peltier elements 10 receives. The Peltier elements 10 have heatsinks directed to the warm side 11 and just, a little smaller sized heat sink 12 , which are directed to the cold side.

Ambient air is through the suction openings 3 in the upper housing part 1 by means of a first fan 13 sucked in and over the heat sink 11 led to the warm side, then to the lateral flow openings 2 withdraw.

The cold side below the support plate 2 has at least one second fan 14 on, from a control unit to be cooled 15 Air sucks to these over the heatsink 12 to lead the cold side and then by means of the exhaust openings 6 attributed to the operating unit cooled.

The arrangement of the Peltier elements 10 or the heat sink 11 and 12 is over the support plate 9 or distributed strictly symmetrically within the housing, wherein the respective second cold side fan preferably at the intersection of diagonally opposite heat sink pairs 5 like this 1b ) shows.

The cooling fins of the heat sink 11 respectively. 12 each extend so that the air flow to the respective side openings passes unhindered to achieve high air velocities, so that in particular in the outer circuit contamination or deposition of dirt particles is prevented.

at realized according to the invention Refrigerators are with a mass between 11kg and approx. 14kg and housing dimensions in the range of 320mm × 240mm × 75mm or 320mm × 430mm × 85mm useful cooling capacity between 75W and 220W has been realized.

Next the current regulation, i. Power control of the Peltier elements, there is the possibility of having one Influencing the speed of the fan used the temperature difference between the inner circuit and the outer circuit to be adjusted so that each an optimal efficiency is achievable.

A Control means for operating the cooling means has as a switch fast-switching MOSFET transistors. The drive via the MOSFET transistors takes place such that at to be aimed at cooling capacity a parallel operation of the Peltier elements takes place. Prevent diodes that for the duration the Pulse shorts result, i. There is a free-wheeling diode circuit here.

The Series connection of the Peltier elements is virtually via the supply of the respective potentials over the MOSFET transistors, which act as switches, superimposed by a parallel circuit. The duration of the transition from series to parallel is by the pulse width and the Pulse rate determined.

1

upper housing part

2

lateral flow openings

3

suction ports in the upper housing part

4

lower housing part

5

Heatsink couples

6

exhaust openings

7

bevelled corner areas

8th

drilling

9

support plate

10

Peltier elements

11

Heat sink warm page

12

Heat sink cold page

13

first Fan

14

second Fan

15

to cooling operating unit

16

suction ports in the lower housing part

Claims (11)

Cooling device with Peltier elements, which have a hot and a cold side, on each of which a heat exchanger is provided, and with an at least two-part housing, in particular for the air conditioning of small appliances and / or operating units, characterized in that a support plate ( 9 ) symmetrically grouped recesses in which Peltier elements ( 10 ) are arranged, wherein in each case the heat exchangers ( 11 ) of the warm side on a first support plate side and the heat exchangers ( 12 ) of the cold side are located on the opposite, second support plate side, on the first support plate side between two of the heat exchangers ( 11 ) a fan ( 13 ) is arranged to dissipate hot air to the environment, on the second support plate side at the intersection of two, each diagonally juxtaposed heat exchangers a fan ( 14 ) is arranged, a first housing part ( 4 ) the second support plate side including heat exchanger and fan ( 14 ), wherein the first housing part ( 4 ) in the suction area of the fan ( 14 ) Suction openings ( 16 ) and laterally opposite outlet openings ( 6 ), all of which are oriented towards the device to be cooled to form a cooling air circuit, and further comprising a second housing part (10). 1 ) the first support plate side including heat exchanger ( 11 ) and fans ( 13 ), wherein the second housing part ( 1 ) at least on two sides opposite formed flow openings ( 2 ) having. Cooling device according to Claim 1, characterized in that the fan or fans arranged on the first support plate side ( 13 ) Are axial fans. Cooling device according to Claim 1, characterized in that the fan or fans arranged on the second support plate side ( 14 ) Are radial fans. Cooling device according to claim 1, characterized in that in each case between two opposite heat exchangers ( 11 ) the warm side a radial fan is arranged, wherein the heat exchanger ( 11 ) Heat sink, which have lying in the flow direction cooling fins or sheets, the second housing part ( 1 ) in the respective suction region of the radial fan suction openings ( 3 ) and the air outlet openings ( 2 ) symmetrically on both sides in the second housing part ( 1 ) are introduced. Cooling device according to claim 4, characterized in that the support plate ( 9 ) and the housing parts ( 1 ; 4 ) have a rectangular shape, wherein the Peltier elements ( 10 ) symmetrically distributed uniformly in the provided recesses of the support plate ( 9 ) are attached and the exhaust openings ( 6 ) extend at least the cold side over the longitudinal sides of the housing part and in this case extend the cooling fins or sheets substantially parallel to the narrow side. Cooling device according to one of the preceding claims, characterized in that the support plate ( 9 ) Has insulating properties and decouples the hot and cold sides of the cooler. cooling device according to one of the preceding claims, characterized that the housing as flat Pack is formed, the useful cooling air flow in substantially perpendicular and the waste heat-cooling air flow substantially parallel runs to the support plate. Method for operating a cooling device according to one of the preceding claims, characterized in that a plurality of Peltier elements ( 10 ) are connected in series and with increased cooling power requirement the Peltier elements ( 10 ) are operated in parallel with switching devices. Method according to claim 8, characterized in that that the Switching devices are clocked. Control device for operating a cooling device according to one of Claims 1 to 7, characterized in that a plurality of Peltier elements ( 10 ) are connected in series and connected in parallel with increased cooling power requirement. Control device according to Claim 10, characterized that the Switching MOSFET's having.