U.S. patent application number 11/795195 was filed with the patent office on 2009-05-21 for switch cabinet.
This patent application is currently assigned to Knuerr AG. Invention is credited to Wolfgang Trepte.
Application Number | 20090126385 11/795195 |
Document ID | / |
Family ID | 36570733 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090126385 |
Kind Code |
A1 |
Trepte; Wolfgang |
May 21, 2009 |
Switch cabinet
Abstract
The invention relates to a switch cabinet with a closed cooling
air circuit and a heat exchanger for dissipating the heat loss from
electronic modular units located in an inner area. For efficient
cooling and to avoid the removal to the switch cabinet environment
of condensate produced in the heat exchanger, at least one
atomizing device is provided and transforms the condensate into
aerosols. The condensate aerosols are immediately resupplied to the
cooling air circuit, preferably the hot, dry exhaust air flow, so
that simultaneously an advantageous atmospheric humidity
stabilization in the switch cabinet is ensured.
Inventors: |
Trepte; Wolfgang;
(US) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
Knuerr AG
Arnstorf
DE
|
Family ID: |
36570733 |
Appl. No.: |
11/795195 |
Filed: |
January 5, 2006 |
PCT Filed: |
January 5, 2006 |
PCT NO: |
PCT/EP06/00063 |
371 Date: |
December 28, 2007 |
Current U.S.
Class: |
62/259.2 ;
62/304 |
Current CPC
Class: |
Y02B 30/80 20130101;
H05K 7/20818 20130101; F24F 2006/125 20130101; Y02B 30/70 20130101;
H05K 7/20754 20130101; F24F 6/14 20130101 |
Class at
Publication: |
62/259.2 ;
62/304 |
International
Class: |
F25D 23/12 20060101
F25D023/12; F28D 5/00 20060101 F28D005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 7, 2005 |
EP |
10 2005 005 588.5 |
Claims
1. Switch cabinet having an inner area for receiving electronic
modular units, a closed cooling air circuit, which has a heat
exchanger for dissipating the heat loss of the electronic modular
units, and with a collecting device for the condensate produced in
the heat exchanger, wherein an atomizing device for the condensate
is provided which transforms the condensate into aerosols, the
condensate aerosols can be supplied to the cooling air circuit for
stabilizing the atmospheric humidity in the switch cabinet and the
atomizing device, relative to the flow direction of the cooling air
circuit, is positioned upstream of the heat exchanger and the
condensate aerosols can be received by hot, dry exhaust air flow
subject to the heat loss of the electronic modular units and can be
transformed into water vapour accompanied by an adiabatic cooling
of the exhaust air flow.
2. Switch cabinet according to claim 1, wherein at least one
ultrasonic vibrator is provided as the atomizing device.
3. Switch cabinet according to claim 1, wherein at least one high
pressure nozzle is provided as the atomizing device.
4. Switch cabinet according to claim 1, wherein the collecting
device for the condensate is a condensate collecting tank placed
below the heat exchanger and a pump and a condensate line are
provided, which supply a predeterminable condensate quantity to the
atomizing device.
5. Switch cabinet according to claim 1, wherein a vibrating tank is
provided for an ultrasonic vibrator as the atomizing device and
into which the condensate can be introduced from the collecting
device.
6. Switch cabinet according to claim 5, wherein the condensate can
be supplied to the vibrating tank with the aid of a bevel, e.g. a
bevelled bottom of the collecting device.
7. Switch cabinet according to claim 1, wherein a piezoceramic
ultrasonic vibrator with a frequency >20,000 Hz or a
magnetostrictive ultrasonic vibrator with a frequency up to 200 Hz
is used as the atomizing device.
8. Switch cabinet according to claim 1, wherein a high pressure
pump is provided, which supplies condensate at a pressure >50
bar to a high pressure nozzle as the atomizing device.
9. Switch cabinet according to claim 1, wherein the atomizing
device can be regulated as a function of the atmospheric humidity
in the supply air flow.
10. Switch cabinet according to claim 1, wherein an overflow device
is provided in the collecting device.
11. Switch cabinet according to claim 1, wherein the heat exchanger
is provided as an air-water heat exchanger in the bottom area of
the switch cabinet.
12. Cooling device for a switch cabinet with a closed cooling air
circuit having a collecting device for the condensate produced,
wherein an atomizing device is provided for the condensate which
transforms the latter into aerosols, the condensate aerosols formed
can be resupplied to the cooling air circuit for stabilizing the
atmospheric humidity in the switch cabinet, and the atomizing
device is positioned upstream of the cooling device, relative to
the flow direction of the cooling air circuit, and the condensate
aerosols can be received by a hot, dry exhaust air flow subject to
the heat loss of electronic modular units and can be transformed
into water vapour accompanied by an adiabatic cooling of the
exhaust air flow.
Description
[0001] The invention relates to a switch cabinet according to the
preamble of claim 1.
[0002] The invention is also suitable for equipment and network
cabinets, in which a cooling air flow is led in rotation and cooled
with the aid of a cooling device. A preferred field of application
is constituted by server cabinets.
[0003] DE 20 2004 006 552.5 discloses a cooling system for
equipment and network cabinets. Electronic modular units, e.g.
servers are located in a sealed inner area, and a closed cooling
air circuit has an air-water heat exchanger for cooling the exhaust
air subject to the heat loss of the electronic modular units. The
air-water heat exchanger is positioned in a lower area of the
cabinet and there is an air guidance with air paths of equal length
and therefore identical air resistances for the individual modular
units, so that to the individual modular units is supplied cold
fresh air with an almost uniform fresh air temperature.
[0004] For dissipating the significant heat losses of high power
processors and servers of the cabinet and whilst taking account of
the fact that generally there are relatively large numbers of such
cabinets in a room or area, the air-water heat exchanger is
connected to the building cold water supply. As a result the entire
heat loss of the cabinets can be dissipated through the building
cold water system and a heat transfer between the installation area
and the cabinets is avoided in a highly cost-saving manner.
[0005] As switch cabinets generally have an airtight construction,
an air exchange between the cabinet interior and the installation
area is avoided. Within the heat exchanger there can be local drops
below the dew point and on using cooling water with a temperature
below 12.degree. C. and/or a high atmospheric humidity in the
installation area condensate is formed within the heat exchanger.
This leads to a drop in the absolute atmospheric humidity within
the switch cabinet, which can lead to damage to the installed
modular units and systems.
[0006] It has been proposed (DE 10 2004 049 487.8) to keep stable
the atmospheric humidity within the cabinet or the cooling air flow
by a clearly defined external air supply. As a function of the
ambient conditions and the target values in the cabinet leaks or
interruptions are formed in the cabinet housing, which ensure a
clearly defined external air supply to the cabinet interior,
particularly in the vicinity of a fan intake side. Through such an
atmospheric humidity stabilization it is possible to avoid the
disadvantages of condensate formation and dehumidification below a
preset value and in particular damage to the equipment and systems
within the cabinet. However, devices are required for removing the
condensate formed.
[0007] DE 298 23 784 U1 discloses a cooling device for a switch
cabinet having a condensate removal unit. The condensate is
collected in a condensate collector and on reaching a presettable
fill level activation takes place of a detector with a float
switch. By means of a drain in the condensate tank and an outlet
line condensate is removed from the cooling device and switch
cabinet.
[0008] WO 01/63713 A1describes a switch cabinet with an air
conditioning device having a refrigeration circuit system with an
evaporator and a condenser. The evaporator together with a fan is
integrated into an evaporator unit and is placed on the switch
cabinet, whereas the condenser with a fan is integrated into the
condenser unit and is arranged in spatially separated manner from
the evaporator unit and switch cabinet, particularly outside the
switch cabinet installation area. This is intended to reduce the
introduction of heat and the noise level in the switch cabinet
installation area, whilst leading to an improved cooling of the
cabinet interior and components located therein. The evaporator
unit has a condensate collector and a condensate evaporating device
and the condensate produced on the evaporator is evaporated and
removed to the outside with a fan.
[0009] In the case of the cooling device described in DE 198 17 247
A1 the devices for leading off the condensate into the switch
cabinet environment are avoided in that the condensate collected in
a collecting device below the cooling device is evaporated with the
aid of a collecting container and a heating element located
therein.
[0010] This counteracts a dehumidification of the cooling air flow.
However, this is linked with a thermal energy supply, so that an
increased cooling capacity of the air-heat exchanger is
necessary.
[0011] The object of the invention is to provide a switch cabinet
with a heat exchanger which, whilst avoiding condensate removal
into the environment, ensures an extremely efficient cooling and
atmospheric humidity stabilization in the switch cabinet.
[0012] According to the invention this object is achieved by the
features of claim 1. Advantageous and appropriate developments
appear in the subclaims and the description relative to the
drawings.
[0013] It is a fundamental idea of the invention to collect the
condensate produced in a heat exchanger in a collecting device and
to transform it into aerosols with the aid of an atomizing device
located in the switch cabinet or heat exchanger and said aerosols
are immediately resupplied to the recycled cooling air.
[0014] As the condensate produced, at least in a predeterminable
quantity, is atomized to an ultrafine mist, particularly with an
aerosol size <0.001 mm, there is no need to remove to the
exterior of the switch cabinet. At the same time a largely stable
atmospheric humidity in the switch cabinet is ensured if the
condensate formed is supplied to the atomizing device, atomized
into condensate aerosols and immediately resupplied to the cooling
air flow.
[0015] It is particularly advantageous if the atomizing device,
relative to the cooling air flow direction, is positioned upstream
of the heat exchanger. The condensate aerosols then pass into the
hot, dry exhaust air flow subject to the heat loss of the
electronic modular units. As a result of the high specific surface
the condensate aerosols are immediately absorbed by said hot, dry
exhaust air flow and evaporate. As a result of the evaporation
there is an adiabatic cooling of the air flow. Thus, less energy is
required during the subsequent cooling of the exhaust air flow in
the heat exchanger.
[0016] It is advantageous to provide as atomizing device one or
more ultrasonic vibrators or ultrasonic atomizers, which have no
heat evolution and which are characterized by a limited size,
pressureless atomization and a low energy demand.
[0017] It is particularly advantageous to use ultrasonic vibrators
with a variable atomizing capacity, so as to be able to ensure a
predeterminable atmospheric humidity in the switch cabinet.
[0018] Appropriately the ultrasonic vibrators are located in a
vibrating tank and are particularly fixed to the bottom of said
tank. In order to maintain a predeterminable liquid level over said
bottom, a sensor, e.g. a float switch can be provided.
[0019] The supply of condensate from the collecting device to the
vibrating tank can take place with the aid of a condensate line
using a pump. It is also possible to provide the collecting device
with a bevel in the direction of the vibrating tank and to equip
the latter with a corresponding supply opening.
[0020] The ultrasonic vibrators can e.g. be piezoceramic vibrators,
which have a frequency >20,000 Hz, or magnetostrictive vibrators
with a frequency up to 200 Hz. Use can also be made of commercial
ultrasonic atomizers with a piezoceramic element, an amplifier for
the mechanical vibrations produced and an atomizer plate on which a
condensate film of limited thickness is excited to capillary waves
and very fine droplets are centrifuged away in a corresponding
trajectory. The liquid film is advantageously formed by a
condensate quantity supplied in pressureless manner.
[0021] It is alternatively possible to provide a high pressure
pump, particularly with a pressure of >50 bar for supplying the
condensate produced to at least one high pressure nozzle, in which
the condensate is atomized to a very fine mist. At least the high
pressure nozzle is again located in the area upstream of the heat
exchanger, so that the fine condensate mist is immediately absorbed
by the dry, hot exhaust air and can rapidly evaporate. It is
possible to use as high pressure nozzles e.g. those types known in
connection with air humidification. Particularly small, rapidly
evaporating condensate aerosols can be formed by an advantageous
pulsating of the condensate flow.
[0022] The invention is described in greater detail hereinafter
relative to the attached drawings, wherein show:
[0023] FIG. 1 A highly diagrammatic representation of a switch
cabinet with an ultrasonic vibrator as atomizing device.
[0024] FIG. 2 A highly diagrammatic representation of a switch
cabinet with a high pressure nozzle as atomizing device.
[0025] The equipment cabinet 2 according to FIG. 2 has an inner
area 3 with vertically superimposed, electronic modular units 4. In
the present example the electronic modular units 4 are servers,
which are in each case received in a housing with not shown air
inlets and outlets and a fan 13.
[0026] The equipment cabinet 2 has a largely airtight construction
and the heat loss of the electronic modular units 4 is dissipated
with the aid of a heat exchanger 5, which is advantageously
constructed as an air-water heat exchanger with connection of the
cooling water to the building cold water supply.
[0027] The bottom of the heat exchanger 5 is located in switch
cabinet 2 and supply air 12 cooled therein is supplied to the
individual modular units 4 by means of a supply air duct 26 in the
vicinity of a front door 23. The exhaust air flows of the
individual electronic modular units pass into an upwardly directed
exhaust air flow 15 within a first exhaust air duct 14 and with the
aid of at least one fan 21 positioned in the vicinity of a back
door 22 are deflected into a second exhaust air duct 16. The
downwardly directed exhaust air flow 17 is supplied to heat
exchanger 5.
[0028] Below heat exchanger 5 is positioned a condensate collecting
tank 8, which in the embodiment according to FIG. 1 is connected by
a condensate line 19 to a vibrating tank 7.
[0029] With respect to the closed cooling air circuit, the
vibrating tank 7 is positioned upstream of the heat exchanger 5,
e.g. with approximately the same level as the condensate collecting
tank 8, and is provided with at least one ultrasonic vibrator 10 as
the atomizing device. The ultrasonic vibrator 10 has a high
frequency generator 9, which extends into the area of a cabinet
base 18.
[0030] When using a piezoceramic ultrasonic vibrator 10 located on
the bottom of vibrating tank 7, the condensate above the same is
vibrated by high frequency a.c. voltage and the propagating
ultrasonic waves bring about the atomization of the condensate,
i.e. the release of very small liquid droplets or condensate
aerosols.
[0031] Through the provision of the atomizing device 10 with the
ultrasonic vibrating tank 7 in the vicinity of the supply of the
hot, dry exhaust air flow 17 to heat exchanger 5, the condensate
aerosols are absorbed and evaporate adiabatically. Associated with
this a cooling takes place and has an advantageous action on the
necessary cooling capacity of heat exchanger 5. Simultaneously as a
result of the condensate atomization the necessary atmospheric
humidity of the air flow in switch cabinet 2 is ensured and damage
associated with dehumidification to the installed modular units is
avoided.
[0032] FIG. 2 shows an alternative atomizing device 20, which is
once again positioned in the vicinity of the hot, dry exhaust air
flow 17 supplied to heat exchanger 5. The further features of
switch cabinet 2 are identical and consequently carry the same
reference numerals.
[0033] A high pressure nozzle 20 is provided as the atomizing
device 20 for the condensate collected in the condensate collecting
tank 8. The condensate from the collecting tank 8 is supplied to
high pressure nozzle 20 with the aid of a high pressure pump
25.
[0034] It falls within the scope of the invention to provide
several high pressure nozzles 20.
[0035] In addition, the invention is not restricted to a switch,
equipment or network cabinet with a heat exchanger at the bottom
and instead covers further cooling devices with condensate
production independently of the positioning thereof. It is e.g.
possible to provide cooling devices having a refrigeration circuit
equipped with an evaporator, a condenser and a compressor, with an
atomizing device according to the invention.
* * * * *