IE20090394A1 - A system for cooling computer racks in a data centre - Google Patents

Abstract

A system (10) for cooling computer racks in a data centre, which system comprises means for measuring the electrical load of the or each computer rack (18), means for regulating the amount of cooling air supplied to the or each computer rack (18) and a control unit (11) in communication with the measuring and regulating means such that the amount of cooling air supplied to the or each computer rack (18) is regulated as a function of an electrical load consumed by the or each computer rack. The system (10) directs cool air where it is needed, which improves the performance of the computer rack and extends the lifespan of computer rack components. The cooling system reduces power consumption of the cooling plant, which in turn reduces the running costs of cooling the computer rack, and also benefits the environment.

Description

Computer and networking equipment are designed to operate within a relatively narrow temperature range. To ensure reliable operation and the longest possible lifespan for components, the temperature of the working environment for such equipment should be maintained within this range.

Computers are increasing in speed, capacity, size and power consumption, causing more heat to be generated when perfonning computing tasks.

There are currently two main methods of cooling a computer rack, namely horizontal and vertical cooling.

Horizontal cooling involves an intake of cold air at the front of the computer rack, a heat exchange occurs with the computer components and hot air is expelled at the back of the computer rack.

Vertical cooling occurs when cold air enters the computer rack at the bottom of the rack, a heat exchange occurs with the computer components and hot air exits the rack at the top. As the air flows to the top of the rack, the temperature of the airflow increases while passing IE 09 03 94 through the computer rack. The computer components located at the top of the rack are exposed to warm air resulting in an inefficient cooling system. Thus, the ideal position for the computer components is at the bottom of the computer rack.

Many computer rack systems use the so-called hot corridor/cold corridor system whereby cool air is supplied via perforated floor tiles positioned near the computer rack. This cool air is guided into the computer rack through perforated panels. However, as the cold corridor is not sealed, air recirculation occurs which leads to a decline of the efficiency of the system.

Data centres that adopt an open plan design without sealed cold corridors regulate the cooling air by identifying ‘hot spots’ and repositioning of perforated tiles or panels that allow cool air to travel to the location of the ‘hot spot’. Hot spots are located by measuring the air temperatures in the data centre. However, as new equipment is added, the location of the hot spots may move, necessitating the moving of the perforated tiles or panels.

Open plan data centres regulate the air volume manually and require the location of hot spots to be identified and monitored. Thus, the regulation of the air temperature is a function of the room temperature profile and is adjusted by trial and error.

An alternative system is to cool a room in which the computer racks are located. However, this system allows mixing of cold and hot IE 0 9 03 94 air which is inefficient. Typically, a computer rack uses horizontal cooling, requiring only cold air intake at the front. However, this system also cools the back of the computer racks, which is unnecessary and power consuming. A further disadvantage of this traditional cooling system is that hot air is able to flow from the back of the computer rack to the front.

Another system of cooling computer racks is based on the principle of complete separation of hot and cold air flows which leads to cooling efficiency improvements. Cold corridors are fully isolated from the rest of the computer rack room. The ends of a cold corridor are sealed off using walls or doors to contain the air. The sealed environment allows the temperature within the cold corridor to be maintained. However, there are a number of drawbacks to this system.

Typically, data centres with sealed cold corridors regulate the air volume as a function of the temperature of the air leaving the computer racks and returning to the hot corridor.

As the cool air passes through the computer rack, and cools the computer rack, the air increases in temperature and passes into the hot corridor as warm air. It is the temperature of the warm air that is measured and determines how much cool air is directed into the cold corridor. The higher the temperature of the air exiting the cold corridor, the more cooling air is directed into the cold corridor. However, the warm air entering a hot corridor may have originated from two or more separate cold corridors which causes difficulties in identifying which cold corridor requires the cold air.

It is an object of the present invention to overcome the disadvantages of the systems for cooling computer racks hereinbefore described.

Accordingly, the invention provides a system for cooling computer racks in a data centre, which system comprises means for measuring the electrical load of the or each computer rack, means for regulating the amount of cooling air supplied to the or each computer rack and a control unit in communication with said measuring and regulating means such that the amount of cooling air supplied to the or each computer rack is regulated as a function of an electrical load consumed by the or each computer rack.

An advantage of the system according to the invention is that it improves the performance of the computers by maintaining a cool working temperature and extends the lifespan of the computer components. The cooling system allows cool air to be directed where it is needed thereby reducing power consumption of a cooling plant, which in turn reduces the running costs of cooling the computer rack, and also benefits the environment.

Another advantage of the system according to the invention is that the cooling air requirements of the computer rack are regulated as a function of an electrical load consumed by the computer rack. A ΙΕ ο 9 03 94 computer rack consuming a higher electrical load will be performing more computing tasks and generating more heat than a computer rack consuming a lower electrical load, and thus will require more cooling. This system allows for an efficient cooling system providing cool air where it is needed most.

According to one embodiment of the invention, the measuring means is an electrical power transducer.

Electrical loads are measured using an electrical power transducer. The transducers are metering instruments designed for continuous monitoring of power usage from current and voltage signals.

The electrical load of the computer rack can be measured at the bus bar or power distribution unit (PDU) of the computer rack. The bus bar or PDU can be wall mounted or located on a computer rack power distribution board.

An advantage of the system according to the invention is that by measuring the electrical load of an individual computer rack the cooling requirements of that computer rack can be calculated and die necessary volume of cool air provided.

According to a further embodiment of the invention, the electrical load can be measured for a row of computer racks.

IE 0 9 0 3 94 An advantage of the system according to the invention is that the sum of the electrical loads being consumed by a row of computer racks can be calculated and the necessary volume of cool air provided to cool the row of computer racks.

The electrical load of a row of computer racks is measured at the bus bar or power distribution unit (PDU) of the row of computer racks. The bus bar or PDU can be wall mounted or located in the row of computer racks.

According to a further embodiment of the invention, the amount of cooling air supplied to the or each computer rack is regulated by modulation of one or more motorised volume control dampers (VCD).

The VCD units are a specific type of damper used to control the flow of air in the cooling system. They consist of valves or plates that regulate the flow of air inside a duct, chimney, variable air volume (VAV) box, air handler, or other air handling equipment. In order to improve efficiency multiple VCDs may be used. In this way, cool air can be directed to specific locations.

An advantage of this feature of the system according to the invention is that one or more motorised VCD units can be modulated independently of one another, thereby allowing cool air to be directed to the computer rack as function of the heat being generated. The VCD units may be positioned in close proximity to the computer rack, below a perforated floor, or behind a perforated wall or ceiling.

The control function can be achieved by inputting electrical power values of current and voltage consumed by a computer rack into the control unit which computes the power value which in turn regulates the VCD units.

This control function may be in the form of an open loop without any feedback. In this case, the modulation of VCD is a preprogrammed setting based on the power value.

Alternatively, the control function may be a closed feedback loop. Feedback signals can include the cool air velocity entering the cold corridor and the cold corridor cooling capacity. The feedback signals enable the control unit to monitor the cold corridor conditions and adjust the modulation of VCD accordingly.

The relationship between electrical power value and the feedback signal can be a pre-programmed relationship.

The VCD units used in accordance with the invention can be composed of a metal, a non-metal, or a composite thereof.

According to a further embodiment of the invention, the VCDs regulate air directed to a row of computer racks.

IE 0 9 03 94 An advantage of this feature of the system according to the invention is that one or more motorised VCD units can be modulated independently of one another, thereby allowing cool air to be directed to a row of computer racks that are consuming a high electrical load and generating heat. The VCD units may be positioned in close proximity to the row of computer racks, below a perforated floor, or behind a perforated wall or ceiling.

An advantage of the system according to the invention is that cold air can be directed to an individual computer rack or a row of computer racks depending on their cooling requirements.

An advantage of this feature of the system according to the invention is that one or more motorised VCD units can be modulated independently of one another, thereby allowing cool air to be directed to the computer rack or computer racks that are generating the most heat. Regulation of the cool air supply is automatic and directed to the location of the greatest heat source.

According to a further embodiment of the invention, the cooling air is generated by a cooling plant.

According to a further embodiment of the invention, the volume of cooling air being generated by the cooling plant can be regulated as a function of the sum of the electrical loads consumed by one or more computer racks.

IE 0 9 0 3 94 An advantage of this feature of the system according to the invention is that the control unit can communicate with the cooling plant and adjust the volume of cool air generated as a function of an electrical load consumed by the or each computer rack.

When planning the cold corridor, the cooling plant size can be determined as a function of the expected computer rack electrical diversity. Alternatively, the varying electrical loads can take cognizance of the cooling capacity of the cooling plant.

The control unit used to regulate the volume of cooling air being generated by the cooling plant may be a separate control unit to the one used to regulate the VCD units.

According to a further embodiment of the invention, the volume of air being generated by the cooling plant can be regulated as a function of static pressure in a supply air plenum.

An advantage of this feature of the system according to the invention is that by preventing variations in the static pressure in the supply plenum results in predictable and controllable cooling system performance.

A further advantage of this feature of the system according to the invention is that an air pressure sensor located in the supply air plenum monitors the air pressure and activates or deactivates the cooling plant accordingly.

IE 0 9 03 94 Cooling capacities available to the cold corridor depend on the amount of pressure that is developed in the supply air plenum. If the static pressure is low, the cooling plant is required to generate more cold air to increase the pressure. If the static pressure is high, the cooling plant will reduce Its cold air output until the pressure has reduced.

A further advantage of this feature of the system according to the invention is that by regulating the air generated and stored in the supply air plenum, increases the operating efficiency and reaction time of the cooling system.

The invention will be further illustrated by the following description of embodiments thereof, given by way of example only with reference to the accompanying drawings in which: Fig. 1 is an end elevation of an embodiment of a cooling system for computer racks according to the invention; and Fig. 2 is a side elevation of a row of computer racks of Fig. 1.

Referring to the Fig. 1 there is indicated, generally at 10, a cooling system for computer racks in a data centre in accordance with the invention. The system 10 comprises a control unit 11 connected to an electrical power transducer 12 and to VCD units 13 (one visible) positioned under a perforated floor 14 of a cold corridor 15. The cold corridor 15 comprises an air-sealed wall 16 mounted around the perimeter of the cold corridor 15 between the perforated floor 14 and a ceiling 17 composed of solid tiles. A row of computer racks 18 is IE 0 9 03 94 arranged along one side 19 of the cold corridor 15 such that fronts 20 of the racks 18 are positioned within the cold corridor 15, and backs 21 of racks 18 are positioned in hot corridor 22.

An opposing row of computer racks 23 makes up other side 24 of the cold corridor 15. Power distribution bus bars 25 provide power to the row of computer racks 18.

Referring to Fig.2, the cooling system as applied to the row of computer racks 18 from Fig. 1, is shown in more detail. Electrical power is delivered to the row of computer racks 18 via the power distribution bus bars 25. The power distribution bus bars 25 is also connected to the electrical power transducer 12. The VCD units 13 are connected to actuator units 26 which are connected to and controlled by the control unit 11.

Referring to Figs 1 and 2, in use an air conditioning cooling plant 27 generates cool air which flows into a floor plenum 28. A pressure sensor 29 monitors the static pressure of the air supply in the floor plenum 28. If the static pressure of the air supply in the floor plenum 28 is low, the cooling plant 27 generates more cold air to increase the pressure. If the static pressure is high, the cooling plant 27 will stop or reduce its cold air output until the pressure has reduced.

When the computer racks 18 are not active, the electrical power transducer 12 measures no power consumption value. The control unit 11 maintains the plates VCD units 13 in a closed position, IE 0 9 0 3 9 4 preventing air from passing from the floor plenum 28, through the VCD units 13 and perforated floor 14 into the cold corridor 15.

If an individual computer rack 18 is active, the electrical 5 power transducer 12 measures the current and voltage values of the computer rack 18 to generate a power consumption value in kWs. The control unit 11 extracts currents of 4-20 mA and voltages of 0-10V as a function of the kW input value. The control unit 11 processes the power consumption value into a predetermined control signal for the VCD units 13.

The control unit 11 activates the VCD units 13 nearest the active computer rack 18 causing the opening of VCD plates (not shown) allowing cool air to pass from the floor plenum 28, through the perforated floor 14 and into the cold corridor 11, directly to the active computer rack 18.

The cool air passes through the active computer rack 18, cooling the computer rack components. The warm air generated in the heat exchange passes into the hot corridor 22.

The VCD units 13 remain open allowing cool air to enter the cold corridor 15 until the electrical power transducer 12 measures a reduction in the power consumption value.

If a row of computer racks 18 is active, the electrical power transducer 12 measures the sum of the current and voltage values of the IE 0 9 03 94 computer racks 18 to generate a power consumption value in kWs. The control unit 11 extracts currents of 4-20 mA and voltages of 0-10V as a function of the kW input value. The control unit 11 processes the power consumption value into a predetermined control signal for the VCD units 13.

The control unit 11 activates the VCD units 13 nearest the active computer racks 18 causing the opening of VCD plates (not shown) allowing cool air to pass from the floor plenum 28, through the perforated floor 14 and into the cold corridor 11, directly to the row of active computer racks 18.

The cool air passes through the active computer racks 18, cooling the computer rack components. The warm air generated in the heat exchange passes into the hot corridor 22.

The VCD units 13 remain open allowing cool air to enter the cold corridor 15 until the electrical power transducer 12 measures a reduction in the power consumption value.

The warm air entering the hot corridor 22 is drawn up through perforated ceiling tiles 30 into a ceiling plenum 31 where it travels to the cooling plant 27 to be cooled before being re-introduced back into the cold air floor plenum 28.

Claims (9)

1. A system for cooling computer racks in a data centre, which system comprises means for measuring the electrical load of the or each computer rack, means for regulating the amount of cooling air supplied 5 to the or each computer rack and a control unit in communication with said measuring and regulating means such that the amount of cooling air supplied to the or each computer rack is regulated as a function of an electrical load consumed by the or each computer rack. 10

2. A system according to Claim 1, wherein the measuring means is an electrical power transducer.

3. A system according to Claim 1 or 2, wherein the electrical load can be measured for a row of computer racks.

4. A system according to any preceding claim, wherein the amount of cooling air supplied to the or each computer rack is regulated by modulation of one or more motorised volume control dampers (VCD).

5. A system according to Claim 4, wherein the VCDs regulate air directed to a row of computer racks.

6. A system according to any preceding claim, wherein the 25 cooling air is generated by a cooling plant. IE Ο 9 Ο 3 9 4

7. A system according to Claim 6, wherein the volume of cooling air being generated by the cooling plant can be regulated as a function of the sum of the electrical loads consumed by one or more computer racks.

8. A system according to Claim 6 or 7, wherein the volume of air being generated by the cooling plant can be regulated as a function of static pressure in a supply air plenum.

9. 10 9. A system according to Claim 1 for cooling computer racks in a data centre, substantially as hereinbefore described with particular reference to and as illustrated in the accompanying drawings.