Apparatus and Methods for Increasing Energy Efficiency of Pumped Refrigerant Cooling Systems

This application claims the benefit of U.S. patent application Ser. No. 17/722,940, filed Apr. 18, 2022, which claims benefit to U.S. Provisional Patent Application No. 63/175,959, filed Apr. 16, 2021, the contents of which are incorporated by reference herein in their entirety.

The present invention generally relates to apparatus and methods for cooling electronic devices. More particularly, the present invention relates to apparatus and methods for cooling heated air emanating from, or entering, electronic equipment to prevent overheating thereof.

Various approaches have been suggested for cooling electronic equipment and rooms. All of these approaches require energy in order to remove heat. One such approach involves utilizing a Refrigerant Pump in order to distribute refrigerant to heat extractors which transfer heat from the air into the refrigerant. This heat is then carried outside by a Secondary Circuit working fluid where it is finally removed either by a water chiller or by a refrigerant-based direct expansion condensing unit.

Energy economization systems in various forms have emerged in order to reduce the amount of energy, and the accompanying energy costs and environmental impact that traditional Secondary Circuit cooling equipment requires.

The present invention introduces an independent Economizer Circuit connected to the Refrigerant Pump which can be used in combination with traditional cooling equipment, including those with other economization systems, for better energy efficiency.

The present invention uses ambient air to reject heat from a working fluid being used to collect heat from the Primary Circuit refrigerant before said heat travels to the Secondary Circuit. This Pumped Refrigerant Economizer System approach reduces the heat load that would otherwise be mitigated by the Secondary Circuit equipment, thereby reducing the amount of energy required to reject said heat load through traditional means (See).

In a preferred embodiment, said System utilizes a dry cooler, which consists of a standard condenser coil coupled with fans to draw ambient air across the coil, and glycol and water mixture as the working fluid which is pumped using a standard variable or fixed speed water pump.

In a preferred embodiment, the present invention utilizes the dry cooler with water pump to deliver cooled glycol and water mixture to a Secondary Heat Exchanger, as shown in, located inside the Refrigerant Pump where heat collected in the Primary Circuit can be transferred to said glycol and water mixture, and then rejected back to outside air at the dry cooler. The Secondary Heat Exchanger may alternatively be located outside of the Refrigerant Pump, either inside or outside of the physical building space data center (e.g., a computer server warehouse) with insulated refrigerant lines as applicable.

The dry cooler discussed above may be used in cooler climates with low average temperatures, however new adiabatic cooling technologies have allowed coolers to work effectively in warmer ambient temperatures as well. Since this equipment does not require compressors, it uses significantly less energy to run than compressor-based technologies. This Economizer Circuit uses glycol and water mixture in the preferred embodiment, however any working fluid may be used.

The present invention may utilize any substitute device that is able to reject collected heat from Secondary Heat Exchanger from the working fluid and then return said cooled fluid to Secondary Heat Exchanger as shown in.

In the embodiment shown in, the present invention combines the dry cooler with a variable speed water pump, a check valve, and a condenser heat exchanger (Secondary Heat Exchanger) which is piped to the return connection of the Primary Heat Exchanger of the Refrigerant Pump.

Additional preferred sensors include a refrigerant temperature sensor to measure return refrigerant temperature, and water temperature sensors to measure the supply and return glycol and water mixture temperatures from the dry cooler. Temperature measurements from the glycol and water mixture temperature sensors may be used to evaluate performance and operation of the Economizer Circuit.

In the case of a variable speed water pump, the water pump speed is commanded by the control software in the control panel of the Economizer Module, as shown in, or of the Refrigerant Pump, in order to increase or decrease water flow as required to reduce the measured error between the target refrigerant temperature setpoint and the measured refrigerant temperature. In the case of a fixed speed water pump, at least one water control valve may be used in order to adjust the glycol and water mixture flow in the Economizer Circuit.

In a more complex embodiment, the dry cooler and water pump described above may provide sufficient water flow and capacity to service multiple Refrigerant Pumps rather than just one. In this case, electronically adjustable water valves may be introduced at each individual Refrigerant Pump in order to control the water flow to each individual Refrigerant Pump. Like the water pump, these water valves may be commanded by the control software of the Economizer Module, as shown in, or of the Refrigerant Pump, in order to increase or decrease water flow as required to reduce the measured error between the target refrigerant temperature setpoint and the measured refrigerant temperature. Additional devices, such as differential pressure regulators, may also be required for proper pressure and fluid flow control.

All software controls previously discussed for control of the water pumps and/or water valves may be substituted by mechanical or electromechanical devices as applicable.

As shown in a preferred embodiment in, the Economization Module which includes the condenser heat exchanger that will be providing system economization, may be modular in nature and able to be installed as an add-on device to existing, non-specific pumped refrigerant systems.

In a preferred embodiment, this Economizer Module may be installed at or vertically above the return connection of the Primary Heat Exchanger in the Refrigerant Pump shown in, in order for gravity to aid in the return and circulation of refrigerant. However, the module may also be installed below said return connection with the help of additional devices and/or methods able to aid in the return and circulation of refrigerant.

Other objects and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention.

Referring to, the present invention introduces an independent Economizer Module/Circuit connected to the Refrigerant Pump which can be used in combination with traditional cooling equipment, including those with other economization systems, for better energy efficiency.

As shown in, a pumped refrigerant cooling systemincludes a refrigerant pumping unit(also referred to as refrigerant pump) having a primary heat exchanger. The refrigerant pumping unitalso includes a tankconnected with primary heat exchanger, and a primary pumpconnected with tank, as shown in. The pumped refrigerant cooling systemalso includes one or more heat extractor(s)(also referred to as evaporator network). The primary pumpof refrigerant pumping unitis connected to heat extractor(s)via a primary circuit. The pumped refrigerant cooling systemalso includes a condensing unit(also referred to as water chiller). The primary heat exchangerof refrigerant pumping unitis connected to condensing unitvia a secondary circuit.

According to an aspect of the present invention, pumped refrigerant cooling systemfurther includes an economizer module(also referred to as pumped refrigerant economizer system) having a secondary heat exchanger(also referred to as condenser heat exchanger) incorporated therein. The economizer modulealso includes a cooler(also referred to as dry cooler, adiabatic chiller, or geothermal cooling). The cooleris connected to secondary heat exchangervia an economizer circuit.

As shown in, economizer module(also referred to as pumped refrigerant or glycol and water mixture economizer system) includes secondary heat exchanger, cooler, and secondary pumpconnected between coolerand secondary heat exchanger, which are connected via economizer circuit. The economizer moduleutilizes coolerwith secondary pumpto deliver cooled working fluid to secondary heat exchanger. Although economizer moduleuses glycol and water mixture as the working fluid according to example embodiments described herein, it should be appreciated that any other suitable working fluid may be used in economizer circuit.

In some example embodiments, the secondary (condenser) heat exchangerof economizer modulemay be located inside refrigerant pumping unit, as shown in, where heat collected in primary circuitcan be transferred to said glycol and water mixture, and then rejected back to outside air at cooler. However, in some other example embodiments, the secondary (condenser) heat exchangermay be located outside of (external to) refrigerant pumping unit, such as either inside or outside of the data center, with insulated refrigerant lines connecting secondary heat exchangerto refrigerant pumping unit. These alternative example embodiments are indicated using dashed lines in.

In some example embodiments, the coolermay be a dry cooler, which includes a standard condenser coil coupled with fans to draw ambient air across the coil, and glycol and water mixture as the working fluid which is pumped using the secondary pump, which may be a standard variable or fixed speed water pump, for example. Utilizing a dry cooler as coolermay be used in cooler climates with low average temperatures.

However, in some other example embodiments, the coolermay be an adiabatic chiller (instead of a dry cooler). Utilizing adiabatic cooling technologies to implement coolermay allow the coolerto work effectively in warmer ambient temperatures as well as colder temperatures, and may also use significantly less energy to run than compressor-based technologies, since adiabatic chiller equipment does not require compressors.

In yet some other example embodiments, the coolermay be implemented using geothermal cooling techniques. This process works like the dry cooler, except instead of cooling fans, piping is sent below the surface of the ground and the earth itself is used as a heat sink. It should also be appreciated that the economizer modulemay utilize any substitute device for cooler(other than the three examples mentioned above) that is able to reject collected heat from secondary heat exchangerfrom the working fluid, and then return said cooled working fluid to secondary heat exchanger, as shown in.

As shown in, economizer modulemay include a control panel, a condenser heat exchanger(the secondary heat exchanger), a refrigerant return, a glycol and water mixture outlet, a glycol and water mixture inlet, and a connection to refrigerant pump return. The secondary heat exchangermay be connected to heat extractor(s)of primary circuitvia refrigerant return, connected to cooler(and optionally control valve) of economizer circuitvia glycol and water mixture outlet, connected to coolerand secondary pumpof economizer circuitvia glycol and water mixture inlet, and connected to the return of primary heat exchangerof refrigerant pumping unitvia connection to refrigerant pump return. Other suitable arrangements or modified configurations for these inlets/outlets/connections are also possible in some other example embodiments. Although not shown in, it should be appreciated that control panelmay include a memory device for storing the control software and a processor configured to execute the control software to implement methods, processes, and/or steps according to example embodiments described herein.

As shown in, economizer moduleincludes secondary pumpconnected between coolerand secondary heat exchanger(the condenser heat exchanger) in economizer circuit. In some example embodiments, economizer modulemay further include a check valve(also referred to as a water control valveor PIVC) connected between secondary heat exchangerand coolerin economizer circuit, as shown in. Inclusion of a check valve or control valvein economizer modulemay be considered optional (as indicated with dashed lines in), and may depend on whether secondary pumpis a fixed speed pump or a variable speed pump, for example.

Thus, according to the example embodiment shown in, the present invention incorporates an independent economizer module/circuit (/) that combines a cooler(e.g., a dry cooler) with a secondary pump(e.g., a variable speed water pump), an optional check valve(e.g., water control valve), and a secondary heat exchanger(e.g., condenser heat exchanger), which is piped to the return connection of primary heat exchangerof refrigerant pumping unit.

Although not shown in the figures, additional preferred sensors may include a refrigerant temperature sensor configured to measure return refrigerant temperature, and water temperature sensors configured to measure the supply and return glycol and water mixture temperatures to and from cooler. Temperature measurements from the glycol and water mixture temperature sensors may be used to evaluate performance and operation of economizer module(and/or economizer circuit), and dynamically make any adjustments if needed.

In the case of a variable speed water pump being used as secondary pumpof economizer module, the water pump speed is commanded by the control software in the control panelof the economizer module, as shown in, or of the refrigerant pumping unit, in order to increase or decrease glycol and water mixture flow as needed to reduce a measured error between a target refrigerant temperature setpoint and a measured refrigerant temperature. In the case of a fixed speed water pump being used as secondary pumpof economizer module, at least one water control valvemay optionally be used in order to adjust the glycol and water mixture flow in economizer circuit(see).

According to a more complex embodiment, coolerand secondary pumpdescribed above may provide sufficient water flow and capacity to service multiple refrigerant pumps, rather than just a single refrigerant pumping unit. In this case, multiple electronically adjustable water valves (not shown in figures) may be introduced at each individual refrigerant pumping unitin order to control the glycol and water mixture flow to each individual refrigerant pump, respectively. Like with secondary pumpand/or control valve, each of these water valves may be commanded by the control software of economizer module(via control panel), as shown in, or of each individual refrigerant pump, in order to increase or decrease glycol and water mixture flow as needed to reduce the measured error between the target refrigerant temperature setpoint and the measured refrigerant temperature. In some example embodiments, one or more additional devices, such as differential pressure regulators (not shown in figures), may also be utilized to ensure proper pressure and working fluid flow control in the case of a single economizer moduleservicing multiple refrigerant pumps.

Although example embodiments described above incorporate software controls for control of the water pumps and/or water valves (e.g., control software stored in a memory and executed by a processor of control panelof), it should be appreciated that one or more suitable mechanical or electromechanical devices may be substituted for the software controls, as applicable. Therefore, example embodiments of the present invention are not limited to the computerized software-based implementation described herein.

As shown in, the economizer module, which includes the secondary (condenser) heat exchangerthat will be providing system economization, may be modular in nature and able to be installed as an add-on device to existing, non-specific pumped refrigerant systems.

In a preferred embodiment, economizer modulemay be installed at or vertically above the return connection of primary heat exchangerin refrigerant pumping unitshown in, in order to allow gravity to aid in the return and circulation of refrigerant. However, economizer modulemay alternatively be installed below said return connection, with the help of one or more additional devices (not shown in figures) and/or methods that are able to aid in the return and circulation of refrigerant.

According to various example embodiments described above, the present invention incorporates an independent Economizer Module/Circuit (,, etc.) that uses ambient air to reject heat from a working fluid (e.g., a glycol and water mixture) being used to collect heat from the Primary Circuit refrigerant (e.g., primary circuitand heat extractor(s)/evaporator network), before said heat travels to the Secondary Circuit (e.g., secondary circuitand condensing unit/water chiller). This Pumped Refrigerant Economizer System approach reduces the heat load that would otherwise be mitigated by the Secondary Circuit equipment, thereby reducing the amount of energy required to reject said heat load through traditional means (See).

Although the invention has been described with reference to example embodiments thereof, it is understood that various modifications may be made thereto without departing from the full spirit and scope of the invention as defined by the claims which follow.