Scope of the Invention

The present invention relates to a data center and more particularly to a data center facility where the equipment/server cabinets and cooling system are housed within a building structure.

Background of the Invention

A typical data center includes a number of server cabinets or racks which house a number of server's and other computer network equipment (hereafter IT equipment) required to operate a data center. In use, the IT equipment consume electricity and generate heat as a byproduct. The IT equipment must be cooled to ensure an operable working environment.

Data center cooling systems which utilize a circulating coolant, as for example water, are known where the heated air generated by the IT equipment is cooled by passing the heated air through a heat exchanger, where the heat from the air is transferred to the circulating coolant and the subsequently cooled air is returned to the data center cabinets. In these coolant based systems which utilize coolant based heat transfer cooling, the resultant heated coolant is typically circulated through a heat rejection system having compressors which rejects the heat from the coolant to the environment outside of the data center, and the subsequently cooled coolant is then re-circulated back to the heat exchanger of the cooling unit. These heat rejection apparatuses are typically oversized for the cooling required, and electrical consumption at the compressors is costly. Free cooling type heat rejection systems, as for example cooling towers, are also know in the art and reject heat from the circulating coolant to the environment outside of the data center. These free cooling type heat rejection system are located outside of the secure building structure of the data center, and therefore pose significant security problems to the proper function of the cooling system of the data center.

Accordingly, there remains a need for an improved, physically secure and fully protected data center and related data center cooling system which reduces energy consumption requirements and enhances the cooling/temperature regulation of the IT computer equipment through an improved low cost and energy efficient heat rejection system for rejecting the waste heat generated by the IT equipment housed in the data center.

Summary of Invention

The present invention has been developed in view of the difficulties in the art noted and described above.

In one aspect, the present invention provides a heat rejection apparatus for rejecting thermal heat energy from a coolant circulating through an air/fluid heat exchanger housed in a data center, the apparatus comprising: a coolant inlet for receiving the coolant from the heat exchanger; a coolant outlet for supplying the coolant to the heat exchanger; an enclosure defining an enclosure space and having an air inlet and an air outlet arranged to define an air flow path through the enclosure space between the air inlet and the air outlet; an evaporative fluid cooling unit disposed in the enclosure space, the evaporative fluid cooling unit comprising an air/coolant interface disposed in the air flow path, at least one sprinkler arranged above the air/coolant interface and connected to the coolant inlet, and a coolant holding tank arranged below the air/coolant interface and connected to the coolant outlet; a convective fluid cooler unit disposed in the enclosure space, the convective fluid cooler unit comprising fluid coils disposed in the air flow path and being connected to the coolant inlet and the coolant outlet; and a valve connected between the coolant inlet, the at least one sprinkler and the fluid coils; wherein the valve is operable to selectively direct the coolant from the coolant inlet to one of the fluid coils of the convective fluid cooler unit and the at least one sprinkler of the evaporative fluid cooling unit based on environmental conditions.

In a further aspect, the heat rejection apparatus may include at least one sensor for measuring the environmental conditions, and a controller for controlling the valve based on the measured environmental conditions.

In a further aspect, the environmental conditions are selected from at least one of ambient air dry bulb temperature and ambient air humidity.

In a further aspect, the heat rejection apparatus may include at least one sensor for measuring air flow rate and coolant flow rate through the heat rejection apparatus, and a controller for controlling the air flow rate and the coolant flow rate through the heat rejection apparatus based on a measurement of electrical consumption by IT equipment housed in the data center.

In a further aspect, the enclosure is a standard data center server cabinet enclosure.

In a further aspect, the at least one sprinkler is operable to sprinkle the coolant through the air/coolant interface, wherein the coolant passing through the air/coolant interface is cooled by evaporative cooling by air flow along the air flow path through the air/coolant interface, and the coolant holding tank is configured to collect and store the coolant passed through the air/coolant interface.

In a further aspect, coolant flow through the fluid coils is cooled by convective cooling by air flow moving across the fluid coils through the air flow path.

In a further aspect, a direction of the coolant passing through the air/coolant interface and a direction of the air flow along the air flow path through the air/coolant interface are substantially parallel.

In a further aspect, a direction of the coolant passing through the air/coolant interface and a direction of the air flow along the air flow path through the air/coolant interface are substantially orthogonal to one another. In a further aspect, the air inlet is positioned in a bottom portion of the enclosure between the coolant holding tank and the air/coolant interface.

In a further aspect, the air outlet is positioned in an upper portion of the enclosure above the at least one sprinkler.

In a further aspect, the fluid coils are disposed in the air/coolant interface to increase splashing of the coolant in the air/coolant interface.

In a further aspect, the air/coolant interface comprises packing to increase splashing of the coolant in the air/coolant interface.

In a further aspect, the fluid coils are arranged below the packing and support the packing thereon.

In a further aspect, the heat rejection apparatus may include an air inlet blower and an exhaust blower, wherein the air inlet blower and the exhaust blower are arranged to direct air flow from the air inlet to the air exhaust through the enclosure space along the air flow path.

In a further aspect, the enclosure is substantially cylindrical.

In a further aspect, the heat rejection apparatus may include an inlet duct having one end connected to the air inlet and an opposing end connectable to a first aperture defined by a data center structural wall; and an outlet duct having one end connected to the air outlet and an opposing end connectable to a second aperture defined by the data center structural wall.

In a further aspect, the heat rejection apparatus is disposed inside of an interior space of the data center, the data center comprising the first aperture and the second aperture, wherein the inlet duct is connected to the first aperture and the outlet duct is connected to the second aperture.

In a further aspect, the present invention provides a data center defining an interior space, the interior space comprising: at least one data center rack for housing IT equipment; at least one heat exchanger unit housing an air/fluid heat exchanger, the heat exchanger unit operable to circulate an air flow between the heat exchanger unit and the at least one data center rack, wherein the heat exchanger transfers thermal heat energy from the air flow to a coolant; and a heat rejection apparatus in communication with the heat exchanger unit and operable to reject thermal heat energy from the coolant, the heat rejection apparatus comprising: a coolant inlet for receiving the coolant from the heat exchanger; a coolant outlet for supplying the coolant to the heat exchanger; an enclosure defining an enclosure space and having an air inlet and an air outlet arranged to define an air flow path through the enclosure space between the air inlet and the air outlet; an evaporative fluid cooling unit disposed in the enclosure space, the evaporative fluid cooling unit comprising an air/coolant interface disposed in the air flow path, at least one sprinkler arranged above the air/coolant interface and connected to the coolant inlet, and a coolant holding tank arranged below the air/coolant interface and connected to the coolant outlet; a convective fluid cooler unit disposed in the enclosure space, the convective fluid cooler unit comprising fluid coils disposed in the air flow path and being connected to the coolant inlet and the coolant outlet; and a valve connected between the coolant inlet, the at least one sprinkler and the fluid coils; wherein the valve is operable to selectively direct the coolant from the coolant inlet to one of the fluid coils of the convective fluid cooler unit and the at least one sprinkler of the evaporative fluid cooling unit based on environmental conditions.

In a further aspect, the data center may include a first aperture defined by a data center structural wall; a second aperture defined by the data center structural wall; an inlet duct having one end connected to the air inlet and an opposing end connected to the first aperture; and an outlet duct having one end connected to the air outlet and an opposing end connected to the second aperture.

Further aspects of the invention will become apparent upon reading the following detailed description and drawings, which illustrate exemplary embodiments of this invention. Brief Description of the Drawings

Reference may now be had to the following detailed description taken together with the accompanying drawings in which:

Figure 1 shows a planar side view of a data center facility in accordance with a preferred embodiment of the present invention.

Figure 2 shows a cross-sectional side view of the fluid heat rejection unit shown in Figure 1.

Detailed Description of the Invention

Reference may now be made to Figure 1 which illustrates an overview of a data center facility 100 in accordance with the present invention. The data center facility 100 includes a building structure defining an interior space 102 enclosed by structural outer walls 104, an upper ceiling 106 and a bottom flooring 108. It is to be noted that the building structure in not limited to a detached building unit, but includes any room or floor within a larger building, as for example a high rise building. Within the interior space 102 there is provided a server cabinet 12, a heat exchanger unit 14, and a fluid heat rejection unit 16.

The cabinet 12 has a box-like frame defining a cabinet interior space. Within the cabinet interior space there is provided a number of horizontal shelves for supporting IT equipment, such as servers. Sensors are provided which measure the amount of electricity consumed by the IT equipment, which is monitored and recorded by a metering system of the data center. The interior space of the cabinet 12 is in air flow communication with the heat exchanger unit 14 through corresponding rear air inlets and front air outlets (not illustrated) provided in the cabinet 12 and the heat exchanger 14. Arranged within the heat exchanger unit 14 there is provided a air/fluid heat exchanger and first and second sets of directional fans/blowers arranged height-wise in the heat exchanger unit 14 (not shown). The first set of directional fans/blowers are arranged at a front portion of the heat exchanger unit 14. The second set of directional fans/blowers are arranged at a back portion of the heat exchanger unit 14.

In operation, hot air is sucked out of the cabinet 12 and into the adjacent heat exchanger unit 14 through the rear air inlets/outlets by means of the second set of directional fans/blowers. The hot air is then blown across the heat exchanger arranged within the heat exchanger unit 14 where water cooled fins remove the heat from the air stream and transfer the heat into the water circulating through the heat exchanger. The cooled air stream is then blown out of the heat exchanger unit 14 with the first set of directional fans/blowers through the air outlets/inlets back into the interior space of the cabinet 12.

The heat exchanger unit 14 is provided with a coolant supply line to supply cooled water to the heat exchanger and is also provided with a coolant exhaust line to remove the heated water from the heat exchanger. Each of the coolant supply line and the coolant exhaust line may be provided with feed pumps, filters, flow rate meters and/or shut off valves. The coolant exhaust line circulates/supplies the heated water to the fluid heat rejection unit 16.

Reference may now be made to Figure 2 which illustrates a fluid heat rejection unit 16 in accordance with the present invention. The fluid heat rejection unit 16 includes a coolant inlet 20 which is connected to the coolant exhaust line of the heat exchanger unit 14 and a coolant outlet 22 which is connected to the coolant supply line of the heat exchanger unit 14.

The fluid heat rejection unit 16 includes an enclosure defining an enclosure space, an air inlet 24 connected to the environment outside of the interior space 102 of the building structure through an intake air duct 26, and an air exhaust 28 connected through an exhaust duct 30 to the environment outside of the interior space 102 of the building structure. A sprinkler 32 is mounted in an upper portion of the enclosure space of the fluid heat rejection unit 16 and is connected to the coolant inlet 20. An air/coolant interface in the form of a packed bed 34 is arranged below the sprinkler 32 and a water holding tank 36 connected to the coolant outlet 22 is positioned below the packed bed 34. Fluid cooler tubes/fins 38 are arranged within the enclosure space of the fluid heat rejection unit 16 and are connected to the coolant inlet and outlet 20, 22 through corresponding tube inlet 40 and tube outlet 42. Preferably, the fluid cooler tubes/fins are made from a copper material. A valve switch 50 is arranged between the coolant inlet 20, the upper sprinkler 32 and the tube inlet 40 so that the valve 50 is operable to selectively direct the circulating coolant (i.e. water) between the sprinkler 32 for evaporative heat rejection or the fluid cooler tubes 38 for convective heat rejection.

The fluid heat rejection unit 16 includes at least one sensor for measuring the environmental conditions, and a controller for controlling the operation of the valve switch 50 based on the measured environmental conditions. Preferably the at least one sensor is located in the intake air duct 26 and the environmental conditions are selected from at least one of ambient air dry bulb temperature and ambient air humidity.

The fluid heat rejection unit 16 also includes at least one second sensor for measuring at least one of air flow rate through the fluid heat rejection unit 16, coolant flow rate through the fluid heat rejection unit 16, and electrical consumption of the fluid heat rejection unit 16 for monitoring by the metering system of the data center. A second controller is provided for controlling the air flow rate and the coolant flow rate through the fluid heat rejection unit 16, and therefore an amount of cooling provided by the heat rejection system, based on the measurement of electricity consumed by the IT equipment, which is monitored by the metering system. Since the heat generated by the IT equipment is directly proportional to the electricity consumed by the IT equipment, the heat rejection unit 16 proactively increases the cooling capacity rather than reactively adjusting the cooling capacity after the heat has been generated by the IT equipment. For example, typical cooling systems control cooling capacity based on temperature measurement validation by monitoring the temperature of the cabinet interior space, and adjusting the air flow rates and coolant flow rates through the cooling systems based on temperature targets. The heat rejection unit 16 on the other hand proactively increases cooling capacity based on the electricity consumed by the IT equipment, actively cooling the IT equipment as it generates the heat. As IT electrical consumption increases, cooling capacity equally increases to maintain the operable working environment of the IT equipment.

Preferably, one end of the intake air duct 26 is directly connected to a first aperture 52 through the building structure wall 104 to intake air from the ambient environment and the other end of the intake duct 26 is connected to the air inlet 24.

Preferably the air inlet 24 is arranged at a bottom portion of the fluid heat rejection unit 16 between the packed bed 34 and the water holding tank 36. Additionally, one end of the exhaust duct 30 is connected to a second aperture 54 through the building structure wall 104 to exhaust air from the fluid heat rejection unit 16 to the ambient environment and the other end of the exhaust duct 30 is connected to the air exhaust 28. Preferably the air exhaust 28 is arranged at a top portion of the fluid heat rejection unit above the packed bed 34.

The fluid heat rejection unit further includes an air inlet blower 60 and an air exhaust blower 70 arranged to direct air flow from the air inlet 24 towards the air exhaust 28 through the fluid heat rejection unit 16.

Preferably the fluid heat rejection unit 16 is substantially the same size as the at least one server cabinet and operable to provide 5 to 75 tons of cooling. By sizing the fluid heat rejection unit 16 to be the same size as the at least one server cabinet, retrofitting an existing data center with the fluid heat rejection unit 16 can easily be done by substituting the fluid heat rejection unit 16 with an existing cabinet housed in the data center. Most preferably the enclosure is a standard server cabinet, as for example a 42 U server cabinet or 52 U server cabinet, as is known in the art.

In operation, by controlling the direction of flow of coolant through the fluid heat rejection unit 16, the fluid heat rejection unit 16 is selectively operable between an evaporative cooling mode and a convective cooling mode for rejecting heat from the circulating coolant to the environment outside the interior space 102 of the data center building structure.

In evaporative operation mode, ambient air from outside of the data center structure is drawn in through the aperture 52 and intake air duct 26 by the air inlet blower

60, preferably through a dehumidifier (not shown) having a humidity control loop, into a bottom portion of the fluid heat rejection unit 16. The air is blown from the bottom portion of the fluid rejection unit 16 through the packed bed 34 towards the air exhaust 28. The heated water supplied by the heat exchanger unit is directed by the valve 50 to the sprinkler 32 which sprinkles the water over the packed bed 34. The sprinkled water passes through a dehumidified air/water interface in the packed bed 34 region where evaporation of a portion of the water removes the heat from the remaining portion of the water. The subsequently cooled remaining portion of the water trickles down through the packed bed 34 and is stored in the water holding tank 36 provided at the bottom of the fluid heat rejection unit 16. The now humidified air is subsequently exhausted from the top portion of the fluid heat rejection unit 16 through the exhaust duct 30 and aperture 54 to the external atmosphere. The cooled water from the holding tank 36 is re-supplied to the heat exchanger of the heat exchanger unit 14 via the coolant outlet 22.

The packed bed 34 is provided with plastic or ceramic packing to increases the "wet surface area" between the circulating water and the dehumidified air blown through the fluid heat rejection unit 16, resulting in improved evaporation cooling of the water, which is re-supplied to the heat exchanger unit 14. In evaporative mode, the heated water can be cooled to a temperature lower than the ambient air dry-bulb temperature, if the external (dehumidified) air is relatively dry (below dew point). As the dehumidified air is drawn past the flow of water at the interface in the packed bed 34, a small portion of the water evaporates, the energy required by this portion of the water to evaporate is taken from the remaining mass of water reducing its temperature (approximately by 970 BTU for each pound of evaporated water). Evaporation therefore results in saturated air conditions, lowering the temperature of the water passing through the unit 16 to a value close to wet bulb air temperature, which is lower than the ambient dry bulb air temperature, the difference being determined by the humidity of the external air. In convective cooling mode, the ambient air is similarly drawn into a bottom portion of the fluid heat rejection unit 16 through the air inlet 24 from outside of the data center structure through the aperture 52 and intake air duct 26 by the air inlet blower. The air is blown from the bottom portion of the fluid rejection unit 16 across the fluid cooler tubes 38 towards the air exhaust 28. The heated water supplied by the heat exchanger unit 14 is directed through the fluid cooler tubes/fins 38 where heat from the water is transferred by convection to the air flow blown across the fluid cooler tubes/fins 38. The subsequently cooled water is re-supplied to the heat exchanger of the heat exchanger unit 14 via the coolant outlet 22.

Preferably, when the ambient air temperature outside of the data center 100 structure is above 10 degree Celsius, the fluid heat rejection unit 16 will operate on evaporative operation mode and when the ambient air temperature outside of the data center 100 structure is below 10 degree Celsius for a period of time greater then 36 hours, the fluid heat rejection unit 16 will operate on convective operation mode.

The present invention provides a cooling system utilizing combined evaporative and convective cooling technology in an enclosed, protected unit that can be located inside of the data center structural facility. The combined packed bed and fluid cooler tubing/fins are housed in a single unit, preferably being a rectangular or cylindrical enclosure. Preferably, the fluid heat rejection unit 16 has a width of about 18 inches to 12 ft and a height of about 5 ft to 180 ft. The unit 16 may also contain a chemical treatment system, where the water hardness is monitored and chemical treated to maintain an acceptable concentration of ions and total dissolved solids. The chemical treat system can also maintain biological sterility, by dispense biocide (sodium Hypochlorite) to maintain water sterility and contain algae and other biological organize growth in the system. It is to be noted that in said evaporative mode, the system operates in an open loop and water must be re-supplied to the system to compensate evaporative losses, whereas in convective more the system is closed loop.

The present invention is cognitive and adaptive based on the environmental ambient conditions and the IT electrical load consumed by the IT equipment to provide free cooling 365 days of the year. Appropriate controls and monitors may be added to self adjust air flow and water rates based on the amount of cooling required (for example controlled by metering system of the data center control system based on IT

consumption). Coolant or water flow path through the fluid heat rejection unit 16 may be based on the measured ambient air temperature. The fluid heat rejection unit 16 may be built to fit within a standard data center cabinet, as for example 2 ft by 4 ft by 6.6 ft tall or larger (standard 42 U or 52 U server cabinets).

To the extent that a patentee may act as its own lexicographer under applicable law, it is hereby further directed that all words appearing in the claims section, except for the above defined words, shall take on their ordinary, plain and accustomed meanings (as generally evidenced, inter alia, by dictionaries and/or technical lexicons), and shall not be considered to be specially defined in this specification. Notwithstanding this limitation on the inference of "special definitions," the specification may be used to evidence the appropriate, ordinary, plain and accustomed meanings (as generally evidenced, inter alia, by dictionaries and/or technical lexicons), in the situation where a word or term used in the claims has more than one pre-established meaning and the specification is helpful in choosing between the alternatives. Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to these particular embodiments. Rather, the invention includes all embodiments, which are functional, electrical or mechanical equivalents of the specific embodiments and features that have been described and illustrated herein. It is to be further understood that the various features and embodiments of the invention disclosed may be combined or used in conjunction with other features and embodiments of the invention as described and illustrated herein.