WO2013066175A1

WO2013066175A1 - System for cooling electronic devices

Info

Publication number: WO2013066175A1
Application number: PCT/NL2012/050761
Authority: WO
Inventors: Kees KOOT
Original assignee: Hiensch Engineering B.V.
Priority date: 2011-10-31
Filing date: 2012-10-31
Publication date: 2013-05-10
Also published as: EP2774463A1; NL2007676C2

Abstract

A system for cooling electronic equipment that is mounted in at least two electronics racks, which electronics racks are disposed some distance apart on a surface in an electronics room, leaving clear a passage therebetween, a special feature being the fact that the system comprises an air conditioning device that is designed to supply cold air from outside the electronics room to the electronics room, and that with a maximum temperature difference.

Description

SYSTEM FOR COOLING ELECTRONIC DEVICES The present invention relates to a system for cooling electronic eguipment that is mounted in at least two

electronics racks, which electronics racks are disposed some distance apart on a surface in an electronics room, leaving clear a passage therebetween. Such an electronics room is in practice often referred to as "datacentre" or computer room.

Such a system is known, for example from US patent No.

2010/0067193 (IBM) . In the past few decades, we have

witnessed the increasing part computers play both in the private sector and in the public sector. So-called

"datacentres " are now found in all sectors, such as the medical sector, the education sector, the communications sector, the business sector, the financial sector and the transport sector. Such datacentres can occupy one room, a floor or even an entire building. Electronic eguipment, such as so-called "servers", for example, is usually mounted in so-called "racks" in datacentres. The racks often have standard dimensions, each rack generally being made up of four vertical rails, with two pairs of opposite rails defining a rectangular space. The vertical rails are

provided with several holes, seen in longitudinal direction, in which supports can be placed for mounting the electronic equipment in the rack. When electronic equipment is thus mounted in racks, large amounts of heat are generated, with the attendant risk of overheating of the electronic

equipment, with all its adverse effects. It is necessary, therefore, to cool the air in a datacentre. A drawback of the prior art is that said cooling in

datacentres is often done in a way that is disadvantageous, seen from an energy point of view, with the cooling of the computers taking place in and inefficient manner.

The object of the invention is to improve the prior art, and in order to accomplish that object a system of the kind described in the introduction is characterised in that the system comprises an air conditioning device that is designed to supply cold air having a temperature varying between 14 °C and 15°C, preferably about 14°C, from outside the

electronics room into the passage in the electronics room, and wherein the air conditioning device is further designed to draw in hot air having a temperature varying between 30°C and 40°C, preferably about 35°C, from the electronic equipment. Preferably, the air conditioning device is designed to supply outside air for generating the cold air. The adiabatic humidification of the cold air functions to achieve the aforesaid temperature of about 14°C and a desired humidity level. Adiabatic humidification of the outside air has a cooling function. Preferably, use is made of at least two humidification installations for said adiabatic humidification. In particular, continuous air circulation takes place, with cold air being supplied by the air conditioning device (making use of an air supplying device to be discussed hereinafter) and hot air being discharged by the air conditioning device.

In this preferred variant, the present system aims at maximising the temperature difference between the cold air and the hot air within the limits of the standards (ASHREA) so as to minimise the transport of air and consequently the consumption of the transport energy and to keep the dimensions of the system as small as possible, wherein the temperatures of the hot air and the cool air are kept at least substantially constant (35°C and 14°C, respectively).

In a further preferred embodiment of a system according to the invention, the air conditioning device functions in the following six working ranges:

- working range A: a condition of the outside air with an enthalpy higher than or equal to 42 kJ/kg;

- working range B: a condition of the outside air with a temperature higher than or equal to 14 °C and an enthalpy ranging between 34 kJ/kg and 42 kJ/kg;

- working range C: a condition of the outside air with a temperature higher than or equal to 14 °C and a humidity higher than or equal to 5.3 g/kg;

- working range D: a condition of the outside air with a temperature higher than or equal to 14 °C and an enthalpy ranging between 28 kJ/kg and 34 kJ/kg;

- working range E: a condition of the outside air with a temperature higher than or equal to 8°C, an enthalpy lower than or equal to 28 kJ/kg and a humidity lower than or equal to 5.3 g/kg;

- working range F: a condition of the outside air with a temperature lower than or equal to 8°C and a humidity lower than or equal to 5.3 g/kg.

In another preferred embodiment of a system according to the invention, the air conditioning device is made up of at least two sub-devices that operate independently of each other. In that case a "double system" is thus used for reasons of safety. In another preferred embodiment of a system according to the invention, the system comprises control means for

controlling the flow of the outside air and the flow of the cold air independently of each other.

In another preferred embodiment of a system according to the invention, the system comprises an air supply device, which air supply device comprises a separate mixing chamber disposed above the passage, wherein the air supply device is designed to blow cold air having a temperature varying between 14°C and 15°C, preferably about 14°C, from outside the electronics room into the mixing chamber, wherein the air supply device is further designed for drawing in hot air having a temperature varying between 30°C and 40°C,

preferably about 35°C, from the electronic equipment in the mixing chamber, subsequently mixing said air with said cold air and subsequently supplying the cool air thus obtained by mixing to the passage in the electronics room, and wherein the air supply device is further designed for controlling the amount of cold air that is blown into the mixing chamber in dependence on a measured temperature of the hot air from the electronics equipment. The box-like mixing chamber is preferably mounted on a ceiling of the electronics room, above the passageway. The cold air is cooler than the hot air, therefore, whilst the hot air is hotter than the cold air .

In a preferred embodiment of a system according to the invention, the air supply device comprises control means for controlling the flow of the cold air and the flow of the cool air independently of each other. In particular, control means are provided for controlling the flow of the cold air (the amount of air being displaced per unit time, expressed in m³/h, for example) in dependence on the measured

temperature of the hot air in the passage from the

electronic eguipment and controlling the flow of the cool air in dependence on the desired blow-in temperature of the cool air. In particular the speed of fans is controlled. In other words, the fans will operate at a higher or a lower speed if the measured temperature exceeds or falls below a predetermined value. In another preferred variant,

additional fans are activated or fans are deactivated in order to increase or decrease the flow of air.

In another preferred embodiment of a system according to the invention, the air supply device is designed for blowing cool air having a temperature varying between 1 °C and 27 °C, preferably about 18°C, into the passage.

The invention will now be explained in more detail with reference to a schematic technical drawing of a preferred variant of the system according to the invention.

The technical drawing shows a system for cooling computers arranged in two racks, 1, 2. As shown, the racks, 1, 2 are disposed in spaced-apart relationship on a floor of a datacentre, leaving clear a cool passage 3. The system comprises an air supply device 4 disposed as a separate unit in the passage 3. The air supply device 4 is designed to mix cold air having a temperature of about 14°C from outside the datacentre and hot air from the computers in a mixing chamber 5. The hot air, which has a temperature of about 35°C, is drawn into the mixing chamber 5. The air mixture having a temperature of about 18°C that has been formed in the mixing chamber 5 is subseguently blown into the passage by the air supply device 4. Fans 6 are used for drawing in the hot air and control valves are used for supplying the cold air. Control means 7 are provided for controlling the speed of the fans 6. This may be necessary if the measured temperature of the cool mixing air from the cold air outside the electronics room and the measured temperature of the hot air from the electronic equipment becomes too high or too low. For example, if the temperature in the passage 3 threatens to fall below 18°C, the speed is increased, and if the temperature in the passage 3 threatens to rise above

18°C, the speed is decreased. Arrows indicate the air flow.

The system further comprises an air conditioning device 8 that is designed to supply the cold air having a temperature of about 14°C to the air supply device 4. In this preferred variant, the air conditioning device consists of two identical sub-devices 9 and 10, which operate independently of each other. Both devices supply outside air so as to generate the cold air having a temperature of about 14°C. Said outside air is cooled and humidified adiabatically, and recuperative energy exchange and/or mixing with the hot air from the electronic eguipment takes place. This will be explained in more detail below with reference to one of the devices 9, 10.

In working range A, outside air is cooled adiabatically, after which a recuperative heat exchanger 11 is used for transferring generated cold to hot return air (i.e. hot air having a temperature of about 35°C that has been drawn in from the computers) . The pre-cooled return air is

subsequently post-cooled to a temperature of about 14°C in a cooling battery 12. Important is that the outside air does not give off moisture to the return air. The working range A applies to an outside air condition exhibiting an enthalpy higher than or equal to 42 kJ/kg.

In working range B the following outside air conditions apply: a temperature higher than or equal to 14 °C and an enthalpy ranging between 34 kJ/kg and 42 kJ/kg. The outside air is cooled adiabatically to a temperature of 14°C and directly supplied to the air supply device 4. The outside air is used directly, therefore, and not mixed with the hot return air.

In working range C the following outside air conditions apply: a temperature lower than or equal to 14 °C and a humidity higher than or equal to 5.3 g/kg. The outside air has a sufficiently low temperature and a sufficient humidity for being mixed with the hot return air to a temperature of about 14 °C. The air mixture is subsequently supplied to the air supply device 4. In working range D the following outside air conditions apply: a temperature higher than or equal to 14 °C and an enthalpy ranging between 28 kJ/kg and 34 kJ/kg. The humidity of the outside air is now too low, whilst the temperature thereof is too high for direct use. The outside air and the return air are mixed until the obtained air mixture has an enthalpy of about 34 kJ/kg. Subsequently, the air mixture is humidified adiabatically to about 14°C. Finally, the air mixture is led to the air supply device 4. In working range E the following outside air conditions apply: a temperature higher than or equal to 8°C, an enthalpy lower than or equal to 28 kJ/kg and a humidity lower than or equal to 5.3 g/kg. The humidity of the outside air is now too low, whilst the temperature thereof is too high for direct use. The outside air is first cooled and humidified adiabatically to a humidity of about 5.5 g/kg. Subsequently, the obtained air is mixed with the hot return air to a temperature of about 14°C. Finally, the air mixture is supplied to the air supply device 4.

In working range F the following outside air conditions apply: a temperature lower than or equal to 8°C and a humidity lower than or equal to 5.3 g/kg. The outside air has a sufficiently low temperature and an insufficient humidity, i.e. the outside air is sufficiently cold but too dry. To keep the humidity inside the datacentre, full recirculation takes place, so that the outside air is not mixed with the hot return air. The heat exchanger 11 is used for supplying the cold that has been obtained to the hot return air, without humidification taking place. Finally, the air mixture is supplied to the air supply device 4. It is noted that the invention is not limited to the preferred variant described herein but that it also extends to other variants that fall within the scope of the appended claims .

Claims

1. A system for cooling electronic equipment that is

mounted in at least two electronics racks, which electronics racks are disposed some distance apart on a surface in an electronics room, leaving clear a passage therebetween, characterised in that the system

comprises an air conditioning device that is designed to supply cold air having a temperature varying between 14°C and 15°C, preferably about 14°C, from outside the electronics room into the passage in the electronics room, and wherein the air conditioning device is further designed to draw in hot air having a

temperature varying between 30°C and 40°C, preferably about 35°C, from the electronic equipment.

2. A system according to claim 1, wherein the air

conditioning device is designed to supply outside air for generating the cold air.

3. A system according to claim 2, wherein the air

conditioning device is designed for humidifying and thus cooling the cold air and the outside air

independently of each other.

4. A system according to claim 1, 2 or 3, wherein the air conditioning device functions in the following six working ranges:

- working range A: a condition of the outside air with an enthalpy higher than or equal to 42 kJ/kg; working range B: a condition of the outside air with a temperature higher than or egual to 14 °C and an enthalpy ranging between 34 kJ/kg and 42 kJ/kg;

working range C: a condition of the outside air with a temperature higher than or equal to 14 °C and a humidity higher than or equal to 5.3 g/kg;

working range D: a condition of the outside air with a temperature higher than or equal to 14 °C and an enthalpy ranging between 28 kJ/kg and 34 kJ/kg;

working range E: a condition of the outside air with a temperature higher than or equal to 8°C, an enthalpy lower than or equal to 28 kJ/kg and a humidity lower than or equal to 5.3 g/kg;

working range F: a condition of the outside air with a temperature lower than or equal to 8°C and a humidity lower than or equal to 5.3 g/kg.

A system according to any one of the preceding claims, 1-4, wherein the air conditioning device is made up of at least two sub-devices that operate independently of each other.

A system according to any one of the preceding claims, 1-5, wherein the system comprises control means for controlling the flow of the outside air and the flow of the cold air independently of each other.

A system according to any one of the preceding claims, 1-6, wherein the system comprises an air supply device, which air supply device comprises a separate mixing chamber disposed above the passage, wherein the air supply device is designed for blowing cold air having a temperature varying between 14 °C and 15°C, preferably about 14 °C, from outside the electronics room into the mixing chamber, wherein the air supply device is further designed for drawing in hot air having a temperature varying between 30°C and 40°C, preferably about 35°C, from the electronic equipment in the mixing chamber, subsequently mixing said air with said cold air and subsequently supplying the cool air thus obtained by mixing to the passage in the electronics room, and wherein the air supply device is further designed for controlling the amount of cold air that is blown into the mixing chamber in dependence on a measured temperature of the hot air from the

electronics equipment.

8. A system according to claim 7, wherein the air supply device comprises control means for controlling the flow of the cold air and the flow of the cool air

independently of each other.

9. A system according to claim 8, wherein the air supply device comprises control means for controlling the flow of the cold air in dependence on the measured

temperature of the hot air from the electronic

equipment and controlling the flow of the cool air in dependence on a desired blow-in temperature of the cool air obtained by mixing.

A system according to claim 7, 8 or 9, wherein the air supply device is designed to blow cool air having a temperature varying between 14 °C and 27 °C, preferably about 18°C, into the passage.