Patent Description:
Cooling systems may cycle a refrigerant to cool a space. Existing cooling systems may use one or more compressors to compress the refrigerant, which is then evaporated to cool a space. Cooling systems using compressors to compress vapor refrigerant suffer from low efficiency and high maintenance. Other refrigeration cycles, such as Stirling cycle refrigeration, exist but have not been successfully applied at non-cryogenic, high capacity commercial refrigeration applications typically supported by conventional vapor-refrigerant- compressing cooling systems.

<CIT> discloses a cooling system including a first refrigeration circuit in thermal communication with a heat load and in fluid communication with a main condenser, a free cooling circuit in fluid communication with the main condenser and a free-cooled water source, a chilled water circuit in fluid communication with the main condenser and an evaporator, and a second refrigerant circuit in fluid communication with the evaporator and a secondary condenser. The free cooling circuit is in thermal communication with the first refrigerant circuit via the main condenser, the chilled water circuit is in thermal communication with the first refrigerant circuit via the main condenser, and the second refrigeration circuit is in thermal communication with the chilled water circuit and the free cooling circuit. The second refrigeration circuit cools a fluid flowing in the chilled water circuit.

<CIT>discloses a thermoelectric heat transferring system comprising a thermoelectric element arranged for a heat flux through the element from the cold side for heat uptake to the hot side for heat dissipation, wherein the heat uptake of the thermoelectric element is arranged by convention, the system further comprising a primary loop for accommodating a cooling liquid for transferring the heat away of the thermoelectric element, wherein the thermoelectric element is arranged for having a maximum heat transfer capacity being higher than the maximum heat dissipation capacity of the primary loop and/or wherein the system is arranged for, manipulation of the flow which affects the stagnant film layer at the heat transmitting surface of the thermoelectric element of the forced convection, to enhance the heat transfer coefficient, and/or wherein a part of the primary loop forms a liquid channel for the heat transmitting surface of the thermoelectric element wherein the direction of the flow is traversing the direction of the liquid flow of the opposite side of the thermoelectric element.

In accordance with the invention there is provided an apparatus, and a method of operating the apparatus, as defined by the appended claims.

Disclosed herein is an apparatus including a separator tank, a heat exchanger, a compressor-less heat separator, and a fluid cooler. The separator tank separates a first refrigerant into a vapor component and a liquid component. The heat exchanger is exposed to a load. The heat exchanger uses the liquid component of the first refrigerant to remove heat from a space proximate the load. The space includes at least one of a refrigeration unit containing the heat exchanger and walk-in cooler or freezer. The compressor-less heat separator extracts heat from the vapor component of the first refrigerant and uses electrical power to move the heat to a second refrigerant. The fluid cooler removes heat from the second refrigerant.

Also disclosed herein is a method, which includes separating a first refrigerant into a vapor component and a liquid component at a separator tank. The method further includes removing heat from a space proximate to the load using the liquid component of the first refrigerant from the separator tank. The space includes a heat exchanger inside a walk-in cooler or freezer. The method further includes extracting heat from the vapor component of the first refrigerant and using electrical power to move the heat to a second refrigerant at a compressor-less heat separator. The method further includes removing heat from the second refrigerant at a fluid cooler.

According to the invention, an apparatus includes a load loop, a vapor loop, and a fluid loop. The load loop includes a separator tank, a heat exchanger and a first pump. The separator tank separates a first refrigerant into a vapor component and a liquid component. The heat exchanger is exposed to a load. The heat exchanger uses the liquid component of the first refrigerant to remove heat from a space proximate to the load. The space includes at least one of a refrigeration unit containing the heat exchanger and walk-in cooler or freezer. The first pump controls a rate of flow of the liquid component of the first refrigerant from the separator tank to the heat exchanger. The vapor loop includes the separator tank and a compressor-less heat separator. The compressor-less heat separator extracts heat from the vapor component of the first refrigerant received from the separator tank and uses electrical power to move the heat to a second refrigerant. The fluid loop includes the compressor-less heat separator, a fluid cooler, and a second pump. The fluid cooler removes heat from the second refrigerant received from the compressor-less heat separator. The second pump controls a rate of flow of the second refrigerant between the fluid cooler and the compressor-less heat separator.

Certain embodiments may provide one or more technical advantages. For example, certain embodiments of compressor-less cooling systems and methods may be more efficient than conventional vapor-compression refrigeration systems and methods used for high capacity cooling or refrigeration. For example, compressor-less cooling systems avoid inherent inefficiencies of the vapor-compression cycle and may utilize more efficient refrigeration cycles to provide cooling. As another example, certain embodiments may use natural refrigerants, e.g., a carbon dioxide refrigerant, eliminating the need for hydrofluorocarbon (HFC) refrigerants that may be optimized for vapor-compression cycles. Using natural refrigerants reduces the environmental impact of cooling systems compared to conventional cooling systems. As yet another example, certain embodiments of compressor-less cooling systems and methods may require less maintenance compared to conventional systems. In particular, the removal of compressors reduces a major maintenance/failure point in conventional vapor-compression cooling systems. Furthermore, certain embodiments of compressor-less cooling systems and methods may reduce noise generated while during operation. Certain embodiments may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.

For a more complete understanding of the present disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:.

Embodiments of the present disclosure and its advantages are best understood by referring to <FIG> of the drawings, like numerals being used for like and corresponding parts of the various drawings.

Cooling systems, such as for example refrigeration systems, use a refrigerant to remove heat from a space. These systems may cycle refrigerant through a plurality of loads located through a building. For example, in a grocery store, loads may be freezers used to store frozen foods or refrigerated shelves used to store fresh produce. Refrigerant may cycle through these freezers and shelves where it is used to remove heat from those spaces.

Existing conventional large capacity refrigeration systems, such as those systems used in commercial spaces, use vapor compression refrigeration. Generally, systems utilizing vapor compression refrigeration cycle a refrigerant through a compressor, which compresses the refrigerant, then through a first heat exchanger, which removes heat from the refrigerant, and then to a second heat exchanger, which uses the refrigerant to remove heat from a space proximate to a load. Typically, the refrigerant is expanded at the second heat exchanger exposed to the load such that it changes from a liquid to a gaseous state. This phase change allows refrigerant within the second heat exchanger to receive heat from the air circulating in the space proximate to the load. For example, in commercial refrigeration systems the load reside within a walk-in freezer or a cooler or an enclosed space in which items are kept at a lower temperature than the ambient temperature.

<FIG> illustrates a typical vapor compression refrigeration cycle in a generalized manner. Cooling system <NUM> comprises a compressor <NUM>, a first heat exchanger <NUM> and a second heat exchanger <NUM> exposed to load <NUM>. Refrigerant flows between compressor <NUM>, first heat exchanger <NUM>, and second heat exchanger <NUM>. The refrigerant is first compressed at compressor <NUM>. Refrigerant flows from compressor <NUM> to first heat exchanger <NUM>. First Heat exchanger <NUM> transfers heat from the refrigerant to the ambient air or another heat transfer medium, e.g., a fluid or a second refrigerant. In first heat exchanger <NUM>, the refrigerant may change phases or otherwise change its temperature or heat in order to be suitable for removing heat from load <NUM>. For example, first heat exchanger <NUM> may be a condenser in which the first refrigerant changes from a gaseous state to a liquid state. After first heat exchanger <NUM>, the refrigerant may flow to a second heat exchanger <NUM> exposed to heat load <NUM>. At load <NUM>, the refrigerant within second heat exchanger <NUM> may be used to remove heat from a space proximate to load <NUM>. Load <NUM> may be a load from a commercial refrigerator, cooler, walk-in freezer, refrigerated display cases, ice machines, chillers, air conditioning apparatuses or similar apparatus. The refrigerant at load <NUM> may be subject to heat transfer such that first refrigerant increases in temperature and/or changes phases from a liquid to a gaseous state. After load <NUM>, first refrigerant may be cycled back to compressor <NUM> wherein the cycle may be repeated. In this manner, cooling system <NUM> represents a generalized refrigeration cycle that is embodies the conventional vapor -compression refrigeration cycle.

Conventional refrigeration cycles such as those represented by cooling system <NUM> in <FIG> have several disadvantages. For example, the vapor-compression refrigeration cycle is less efficient than other refrigeration cycles, such as the Stirling cycle. As another example, conventional vapor-compression refrigeration systems use hydrofluorocarbons (HFCs) and do not easily accommodate the use of natural refrigerants, such as carbon dioxide (CO<NUM>), which may be more environmentally friendly. For example, natural refrigerants may require additional considerations in their application, and thus complicate the simple vapor-compression systems that use HFCs. Using CO<NUM> requires high pressures (requiring more expensive components and piping) and loses efficiency at high ambient temperatures (necessitating compensating by adding components to increase efficiency). Ammonia is toxic, flammable, and cannot be used with copper tube and piping. Hydrocarbons are highly flammable and currently not allowed by building codes.

Several measures have been introduced to deal with the various drawbacks of the vapor-compression cycle, including adding components to increase efficiency or allow for the use of natural refrigerants. In addition, typical vapor-compression cycle compressors and other components have less favorable life cycle climate performance (LCCP) ratings, which represent the higher environmental impact these systems have over their lifetime. Moreover, the typical components of vapor-compression cycle refrigeration systems, including the compressors, produce a large amount of noise, which may render certain spaces unusable during operation or inconvenience customers or employees or prevent regulatory compliance in some markets in which noise is regulated. Instead of attempting to provide marginal improvements to systems using the vapor-compression cycle, what is needed are alternative refrigeration systems which obviate the need for a compressor and are also able to operate with high capacity, matching systems using the vapor compression cycle.

This disclosure contemplates various embodiments of cooling systems and methods of cooling a space which utilize a compressor-less heat separator. The compressor-less heat separator may be any suitable heat transfer device that is able to receive two fluids and exchange heat between them without the use of a compressor. In certain embodiments, the compressorless heat separator may use a third fluid to accomplish its function. For example, the heat separator may be a high capacity Stirling cooler, a thermoelectric cooler, a magnetic cooler, or a thermoacoustic cooler. The use of such heat separators allows the removal of any compressor devices that are the main source of many of the drawbacks discussed above in the vapor-compression cycle. Although non-vapor compression cycles have been contemplated before, this disclosure includes various systems and methods that are able to utilize compressor-less heat separators for high capacity refrigeration. For example, certain embodiments may include commercial refrigeration devices such as a walk-in cooler, freezer, or large-scale coolers. A heat separator on its own is unable to provide such cooling and requires additional components to provide the high capacity refrigeration in a controlled manner. The control of the heat transfer using the heat separator requires different considerations than those concerned with the vapor-compression refrigeration systems, and are contemplated herein.

<FIG> illustrates an example cooling system <NUM>. Cooling system <NUM> includes a heat separator <NUM>, a separator tank <NUM>, a heat exchanger <NUM> exposed to a load <NUM> and a fluid cooler <NUM>. As illustrated in <FIG>, the various components of cooling system <NUM> may be connected by any number of various types of pipes, tubing, or similar means which are suitable to flow fluid under a pressure and temperatures typical of typical refrigerants and commercial cooling systems.

Cooling system <NUM> may be considered as having three circuits or loops. For example, cooling system <NUM> may have a "load loop" which includes separator tank <NUM> and heat exchanger <NUM> exposed to load <NUM>. A first refrigerant may flow from separator tank <NUM> to heat exchanger <NUM>. In a similar manner as described with respect to <FIG>, heat exchanger <NUM> may use the first refrigerant in removing heat from a space proximate to load <NUM>. Load <NUM> may comprise a load from one or more of a commercial refrigerator, cooler, walk-in freezer, refrigerated display cases, ice machines, chillers, air conditioning apparatuses and/or similar apparatus. In certain embodiments, the space proximate to load <NUM> may include at least one of a refrigeration unit and a walk-in freezer. After removing heat from a space proximate to load <NUM>, the first refrigerant flows back to separator tank <NUM> through a first inlet <NUM>. The loop may repeat continuously or may be cycled on and off according to various control mechanisms and/or automatic criteria.

Cooling system <NUM> may also have a "vapor loop" in which a vapor component of the first refrigerant flows from separator tank <NUM> to heat separator <NUM> and back into separator tank <NUM> through a second inlet <NUM>. For example, a vapor component of first refrigerant flows from vapor outlet <NUM> to heat separator <NUM>. At heat separator <NUM>, electricity may be used to extract heat from the first refrigerant move heat to a second refrigerant. After heat is extracted from the vapor component of the first refrigerant, the first refrigerant flows back to separator tank <NUM> through second inlet <NUM>. After heat is extracted from the vapor component of first refrigerant in heat separator <NUM>, the first refrigerant flowing from heat separator <NUM> may comprise a liquid component of the first refrigerant as a result of the lower heat and/or pressure within first refrigerant after the transfer of heat in heat separator <NUM>. In some embodiments, the first refrigerant flowing from heat separator <NUM> may include only a liquid component of the first refrigerant.

Cooling system <NUM> may also have a "fluid loop" which comprises heat separator <NUM> and fluid cooler <NUM>. The second refrigerant may flow between heat separator <NUM> and fluid cooler <NUM>. For example, the second refrigerant may flow from fluid cooler <NUM> to heat separator <NUM>. Inside heat separator <NUM>, heat is extracted from the first refrigerant using electricity and the extracted heat is moved to the second refrigerant. After heat is transferred from the first refrigerant to the second refrigerant, the second refrigerant may further transfer heat into fluid cooler <NUM> in which heat is transferred to another medium such as the ambient environment around fluid cooler <NUM>. As described above, these three loops make up a compressor-less cooling system <NUM> that uses a first refrigerant and a second refrigerant in order to service load <NUM>. While this particular configuration may be used to utilize heat separator <NUM> for high-capacity cooling, other such combinations of loops using heat separator <NUM> may be contemplated.

Cooling system <NUM>, in certain embodiments, may further include a first pump <NUM>. First pump <NUM> may control a rate of flow of the liquid component of the first refrigerant from separator tank <NUM> to heat exchanger <NUM> exposed to load <NUM>. For example, first pump <NUM> may comprise various settings that control the rate of flow of the first refrigerant between separator tank <NUM> and heat exchanger <NUM>. As an example, when additional heat transfer is required at to remove heat at load <NUM>, first pump <NUM> may operate at a higher setting such that the first refrigerant is flowed at a higher rate from separator tank <NUM> to heat exchanger <NUM>.

In certain embodiments, the flow rate of the vapor portion of the first refrigerant to heat separator <NUM> may be a result of the heat exchange by heat exchanger <NUM> exposed to load <NUM>. For example, when load <NUM> at heat exchanger <NUM> causes more liquid in heat exchanger <NUM> to evaporate, e.g., at a unit cooler of heat exchanger <NUM>, more of the vapor component of the first refrigerant is available to heat separator <NUM>. In this case, if heat separator <NUM> has enough capacity at its operator power at this time, heat separator <NUM> may condense more of the supplied vapor component of the first refrigerant to send back to separator tank <NUM>.

In certain embodiments, cooling system <NUM> may not include pump <NUM> or any pump between separator tank <NUM> and heat exchanger <NUM> exposed to load <NUM>. For example, cooling system <NUM> may be configured such that the liquid component of the first refrigerant is flowed to heat exchanger <NUM> without pump <NUM>. Similarly, the vapor component of the first refrigerant may be provided to heat separator <NUM>. In this manner, certain embodiments may have a simplified configuration without the need of pump <NUM>. Separator tank <NUM> may include any suitable components with which the liquid component and the vapor component of a refrigerant or other heat transfer media may be separated. According to the invention, separator tank <NUM> includes first inlet <NUM> and second inlet <NUM> that is configured to receive the first refrigerant. For example, first inlet <NUM> may receive the first refrigerant in a vapor-only or a <NUM>-phase mixture of vapor and liquid from heat exchanger <NUM>. As another example, second inlet <NUM> may receive first refrigerant in substantially a liquid phase, and in some cases, only in a liquid phase without a vapor component. In some embodiments, first inlet <NUM> and second inlet <NUM> are distinct inlets, both residing above the liquid level in separator tank <NUM>. In certain embodiments, separator tank <NUM> may include more than one inlet in which vapor and liquid may flow into separator tank <NUM> separately. Various separation tanks may be contemplated. For example, any suitable vapor-liquid separation tanks, such as flash gas tanks and other refrigerant vapor liquid separators may be contemplated in this disclosure.

In certain embodiments, separator tank <NUM> within cooling system <NUM> may be configured to prevent any liquid component of the first refrigerant from flowing to heat separator <NUM>. Heat separator <NUM> may only use a vapor component of the first refrigerant in which to transfer heat to the second refrigerant. Liquid flowing to heat separator <NUM> may decrease the efficiency of heat separator <NUM> by reducing the latent heat extraction at heat separator <NUM>. In this manner, providing only a vapor component of the first refrigerant to heat separator <NUM> may increase its efficiency and the amount of heat available for extraction. Separator tank <NUM> provides simple and effective control of the flow of the first refrigerant while still enabling the efficient heat transfer at heat exchanger <NUM> and heat separator <NUM>.

Fluid cooler <NUM> may comprise any suitable fluid cooling device. In certain embodiments, fluid cooler <NUM> may include a coil and fan combination which enables heat transfer from the second refrigerant to the air passing over the coils using the fan. Other fluid cooling devices may be used in combination or in the alternative. For example, direct or indirect evaporative cooling may be used in conjunction with the coil and fan combination in fluid cooler <NUM>. In another example, an additional liquid may be used by fluid cooler <NUM> to transfer heat from second refrigerant.

In particular embodiments, the additional liquid may be part of a heat reclamation system. For example, the additional liquid may be water that may be heated with the waste heat from heat separator <NUM>. In this example, the heated water may reduce the need to provide energy to heat water for use as sanitary hot water in a supermarket or restaurant. In this manner, additional efficiencies may be provided by cooling system <NUM>.

In certain embodiments, the first refrigerant comprises carbon dioxide. Carbon dioxide is an environmentally friendly alternative to conventional refrigerants, but in conventional cooling systems, such as the cooling system <NUM>, using carbon dioxide results in lower efficiency at high ambient temperatures and requires the use of additional components to negate some of the disadvantages compared to HFCs or other artificial refrigerants. Using carbon dioxide as the refrigerant may also require more expensive components that are rated at higher pressures. Cooling system <NUM> may use, however, natural refrigerants, such as carbon dioxide, while maintaining high efficiency and simplified construction. In this manner, cooling system <NUM> allows heat separator <NUM> to use refrigerants, such as natural refrigerants, with high efficiency without overly complex or expensive configurations or components.

The second refrigerant used in heat separator <NUM> and fluid cooler <NUM> may include any suitable refrigerant. In certain embodiments, the second refrigerant may include water. In some embodiments, the second refrigerant may include a water-glycol mixture. For example, heat separator <NUM> may be configured to receive a water-glycol mixture at a low temperature portion and eject the water-glycol mixture to the fluid cooler <NUM> after transferring heat from the first refrigerant. In this manner, a water-glycol mixture may provide an easy and cost-effective second refrigerant that requires little maintenance and is easily replaced. In certain embodiments, more efficient or advanced refrigerants may be used for second refrigerant. In some embodiments, additional equipment may be used in conjunction with the different refrigerants.

In certain embodiments, heat separator <NUM> may be a compressor-less heat transfer device which uses a power source to extract and move heat. For example, heat separator <NUM> may be a thermal electric heat transfer device. In another example, heat separator <NUM> may be a magnetic heat transfer device. In a further example, heat separator may be a thermo-acoustic heat transfer device. In yet another example, heat separator <NUM> may be a Stirling cycle heat transfer device. These example compressorless heat transfer devices do not require additional compression in order to move heat from the first refrigerant to the second refrigerant. In the case of Stirling cycle and thermoacoustic heat transfer devices, a third refrigerant may be used to effectuate the heat transfer. For example, the third refrigerant may be used with the application of electrical power to move the heat from the first refrigerant to the second refrigerant. The removal of the compressor from cooling or refrigeration systems provides several advantages as discussed above. In particular, compressor-less cooling systems may be more efficient, require less maintenance, lessen environmental impact, and generate less noise. One further advantage of certain embodiments disclosed herein is the ability to easily scale load <NUM> serviced by heat separator <NUM> as more efficient and higher capacity compressor-less heat transfer devices are developed.

In addition, compressor-less heat transfer devices may include additional efficiency factors over traditional compressor systems. For example, compressor-less devices may retain higher efficiency at part-load conditions due to the ability to retain high efficiency at less than full power. In contrast, vapor-compression systems typically only are efficient in certain power ranges and typically cycled to run only at those full load conditions. The vapor-compression systems pay a efficiency penalty associated with each on-off cycle.

In certain embodiments, cooling system <NUM> may include one or more sensors. For example, as shown in the embodiment disclosed in <FIG>, cooling system <NUM> may include a first temperature sensor <NUM>. Temperature sensor <NUM> may be coupled to the cycle including heat separator <NUM> and fluid cooler <NUM> as depicted in <FIG>. Temperature sensor <NUM> may be configured to measure a temperature of the second refrigerant as it flows between heat separator <NUM> and fluid cooler <NUM>. This temperature may represent the amount of heat transfer heat separator <NUM> and/or the amount of heat transfer at fluid cooler <NUM>. In certain embodiments, a temperature value from temperature sensor <NUM> may compared to a temperature set point. Based on that comparison between the measured temperature from temperature sensor <NUM> and the temperature set point, the rate of flow of the second refrigerant may be increased between heat separator <NUM> and fluid cooler <NUM>. For example, if the temperature of the second refrigerant reaches above a certain temperature threshold, a pump, such as second pump <NUM>, may be operated to increase the flow of the refrigerant at a higher rate between heat separator <NUM> and fluid cooler <NUM>. As a result, heat separator <NUM> may be provided with more capacity for heat transfer using the second refrigerant, e.g., more heat may be transferred from the first refrigerant the second refrigerant at a higher rate due to the increased flow of the second refrigerant.

In particular embodiments, cooling system <NUM> may include one or more fans configured to blow air across heat exchangers in cooling system <NUM>, including one or more of fluid cooler <NUM> and heat exchanger <NUM>. In some embodiments, the one or more fans are variable speed fans. The speed of fans may be varied based on the load exposed to the heat exchangers. For example, the speed of a fan proximate to heat exchanger <NUM> may be increased in response to an increase of load <NUM> in order to remove more heat from the space proximate load <NUM>. In certain embodiments, based on that comparison between the measured temperature from temperature sensor <NUM> and the temperature set point, the speed of one or more fans may be increased to increase heat transfer.

In certain embodiments, other components of cooling system <NUM> may be controlled using temperature values from temperature sensor <NUM>. In some embodiments, fluid cooler <NUM> may change its operation state if the measured temperature of the second refrigerant exceeds a threshold or predetermined value. For example, fluid cooler <NUM> may be controlled to turn on a fan or increase the speed of a fan or any other heattransfer media moving device to increase the heat transfer from second refrigerant at fluid cooler <NUM>.

In certain embodiments, cooling system <NUM> may also comprise pressure sensor <NUM> and temperature sensor <NUM>. In such embodiments, one or more of pressure sensor <NUM> and temperature sensor <NUM> may be used to control the flow of the first refrigerant. For example, in certain embodiments, pressure sensor <NUM> may be configured to measure a pressure of the first refrigerant and temperature sensor <NUM> may be configured to measure a temperature of the first refrigerant. The measurement of the temperature and pressure of the first refrigerant may be used to determine a load value that is based on the measured temperature and pressure. This load value may be compared to a set point. For example, the load value may be compared to a set point based on a refrigerant curve, such as a P-T curve, that represents the desired cooling at load <NUM> or of the space proximate to load <NUM>. Based on the comparison of the load value and the set point, the rate of flow of the first refrigerant to heat exchanger <NUM> may be increased. For example, first pump <NUM> may be operated at a higher rate to flow the first refrigerant at a higher rate from separator tank <NUM> to heat exchanger <NUM> and from separator tank <NUM> to heat separator <NUM>. As another example, a speed of a fan proximate to heat exchanger <NUM> may be increased based on a comparison of the load value and the setpoint.

Cooling system <NUM> may also include a controller, such as controller <NUM> described in <FIG>. The controller, e.g., controller <NUM>, may be coupled to one or more components of cooling system <NUM>. In accordance with the invention, the controller <NUM> is communicatively coupled to temperature sensor <NUM>. Controller <NUM> may be configured to compare the measured temperature to a set point and based on that comparison, increase a rate of flow of the liquid component of the first refrigerant to heat exchanger <NUM>. In certain embodiments, controller <NUM> may be coupled to fluid cooler <NUM>. In such embodiments, controller <NUM> may be configured to increase a speed of fan in fluid cooler <NUM> to increase the heat transfer from second refrigerant to the ambient temperature or to another heat transfer medium. In certain embodiments, controller <NUM> may be coupled to second pump <NUM>. For example, controller <NUM> may be configured to change the rate at which second pump <NUM> operates, thereby controlling the rate of flow of the second refrigerant between heat separator <NUM> and fluid cooler <NUM>. In this manner, controller <NUM> may be configured to control the heat transfer rate and capacity of the second refrigerant in heat separator <NUM>.

In certain embodiments, controller <NUM> may be coupled to the pressure sensor <NUM> and temperature sensor <NUM>. Controller <NUM> may be configured to determine a load value based on a measured temperature from temperature sensor <NUM> and the pressure measured with pressure sensor <NUM>. Controller <NUM> may be further configured to compare the load value to a set point and based on the comparison, increase the rate of flow of the liquid component of the first refrigerant to heat exchanger <NUM>. For example, in certain embodiments, controller <NUM> may be coupled to first pump <NUM> and operable to change the rate of flow of first refrigerant by changing the state of first pump <NUM>. By increasing the flow rate through first pump <NUM>, the liquid component of first refrigerant may flow at a higher rate from separator tank <NUM> to heat exchanger <NUM>, thereby increasing the heat transfer capacity of the first refrigerant at load <NUM>.

Various set points and predetermined values may be used in order to control various components of system <NUM>. For example, a temperature set point may be set individually for each of the first refrigerant and the second refrigerant. Different set points may be used for different modes of operation based on other readings or predetermined information. For example, the time of day, the ambient temperature, the humidity, and considerations may be used by controller <NUM> or by an operator of cooling system <NUM> in order to control the flow and/or operation of any of the components of cooling system <NUM>.

In certain embodiments, one or more heat separators <NUM> may be disposed in series or parallel. For example, heat separator <NUM> may comprise one or more heat transfer devices. In certain embodiments, the plurality of heat transfer devices are configured in parallel. In certain embodiments, the plurality of heat devices of heat separator <NUM> are configured in series. In certain embodiments, the plurality of devices of heat separator <NUM> are configured in both series and parallel. For example, heat separator <NUM> may comprise four heat transfer devices and configured in two pairs. Each pair being configured in parallel and the two pairs being configured in series. In addition, various configurations may be applied to fluid cooler <NUM> and/or heat exchanger <NUM>. For example, a plurality of fluid coolers <NUM> and/or heat exchangers <NUM> may be configured in cooling system <NUM>. Furthermore, heat separator tank <NUM> may comprise multiple separation tanks and/or stages within each separation tank <NUM>. In this manner, cooling system <NUM> may be easily scaled to service larger or more loads <NUM> efficiently and/or with more control.

Certain embodiments of cooling system <NUM> may provide one or more technical advantages. For example, cooling system <NUM> may be more efficient than conventional vapor-compression refrigeration systems used for high capacity cooling or refrigeration. For example, cooling system <NUM> avoids the inherent inefficiencies of the vapor-compression cycle and may utilize more efficient refrigeration cycles to provide cooling for home and commercial applications, such as for a walk-in freezer or refrigeration unit. As another example, cooling system <NUM> may use natural refrigerants, e.g., a carbon dioxide refrigerant, without the need for specialized equipment or components, thereby providing high capacity cooling while remaining environmentally conscious. As yet another example, cooling system <NUM> may require less maintenance compared to existing vapor-compression systems. In particular, the lack of a compressor reduces a major maintenance and failure point in existing conventional vapor-compression cooling systems.

<FIG> is a flowchart illustrating a method <NUM> of operating the example cooling system <NUM> of <FIG>. In particular embodiments, various components of cooling system <NUM> perform the steps of method <NUM>. Method <NUM> may begin with step <NUM>. In step <NUM>, separator tank <NUM> separates a first refrigerant into a vapor component and a liquid component. The vapor component and the liquid component may be separated within different portions of separator tank <NUM> by any suitable means. The liquid component of the first refrigerant may then flow from separator tank <NUM> heat exchanger <NUM>.

At step <NUM>, heat exchanger <NUM> uses the liquid component of the first refrigerant to remove heat from a space proximate to load <NUM>. For example, a portion of the liquid component of the first refrigerant may be evaporated at heat exchanger <NUM> in order to facilitate heat transfer from the ambient air in the space proximate to load <NUM> to the first refrigerant. After the transfer of heat, the first refrigerant may flow from heat exchanger <NUM> back to separator tank <NUM>.

At step <NUM>, heat separator <NUM> may extract heat from a vapor component of the first refrigerant and, using electrical power, move the heat to a second refrigerant. For example, heat separator <NUM> may receive the vapor component of the first refrigerant from separator tank <NUM> and using electrical power, extract heat from the vapor component, thereby condensing the first refrigerant, and move the heat to the second refrigerant. In certain embodiments, a portion of the vapor component of the first refrigerant may condense, forming both a vapor component and a liquid component of the first refrigerant. In some embodiments, the entire portion of the vapor component of the first refrigerant condenses, forming solely a liquid component of the first refrigerant. The first refrigerant may flow back to separator tank <NUM> from heat separator <NUM>.

At step <NUM>, fluid cooler <NUM> may remove heat from the second refrigerant. For example, after receiving heat at heat separator <NUM> from the first refrigerant, the second refrigerant may be received at fluid cooler <NUM>. Fluid cooler <NUM> may pass the second refrigerant through a series of coils to transfer heat from the second refrigerant to the ambient air proximate to fluid cooler <NUM>. In certain embodiments, fluid cooler <NUM> may use fans to pass air over the coils in order to enhance the transfer of heat from the second refrigerant to the ambient space proximate to fluid cooler <NUM>. In certain embodiments, step <NUM> may include substeps wherein the second refrigerant is used as part of a heat reclamation system. For example, the second refrigerant may be water that is heated for use of a sanitary water system for a supermarket or restaurant.

While certain methods have been described to remove heat from the second refrigerant, any suitable means may be used to remove heat from the second refrigerant.

In particular embodiments, method <NUM> may comprise additional steps. As an example, there may be additional steps to control the rate of flow of the liquid component of the first refrigerant and a rate of flow of the vapor component of the first refrigerant from the separator tank <NUM>. For example, first pump <NUM> may control the rate of flow of the liquid component of the first refrigerant from separator tank <NUM> to heat exchanger <NUM> and the rate of flow of the vapor component of the first refrigerant from separator tank <NUM> to heat separator <NUM>. Furthermore, a rate of flow of the second refrigerant may be controlled between a fluid cooler <NUM> and heat separator <NUM> using second pump <NUM>. As an additional example, method <NUM> may include further steps of measuring temperatures and pressures of the first refrigerant and second refrigerant as discussed in reference to <FIG> and cooling system <NUM> above. Method <NUM> may comprise steps of comparing various temperatures and pressures of the first refrigerant and the second refrigerant and changing the flow of one or more of the first refrigerant and second refrigerant to various components of cooling system <NUM> based on the comparisons. As yet another example, method <NUM> may further comprise steps of separating the first refrigerant into a vapor component and a liquid component and discharging the vapor component and the liquid component to heat separator <NUM> and heat exchanger <NUM> respectively. Any additional steps, as with any of the steps in method <NUM>, may be carried out by controller <NUM> coupled to components of cooling system <NUM> automatically or manually. For example, one or more of steps may be carried out manually by an operator or may be carried out automatically based on predetermined set points or desired operational ranges.

Modifications, additions or omissions may be made to method <NUM> depicted in <FIG>. Method <NUM> may include more or fewer or other steps. For example, steps may be formed in parallel or in any suitable order. While discussed as various components of cooling system <NUM> performed the steps, any suitable component or combination of components of cooling system <NUM> may perform one or more of the steps above.

<FIG> illustrates an example controller <NUM> of cooling system <NUM>, according to certain embodiments of the present disclosure. Controller <NUM> may comprise one or more interfaces <NUM>, memory <NUM>, and one or more processors <NUM>. Interface <NUM> receives input (e.g., sensor data or system data), sends output (e.g., instructions), processes the input and/or output, and/or performs other suitable operation. Interface <NUM> may comprise hardware and/or software. As an example, interface <NUM> receives information (e.g., temperature and/or pressure information) about one or more components of refrigeration system <NUM> (e.g., via sensors).

Memory (or memory unit) <NUM> stores information. As an example, memory <NUM> may store method <NUM>. Memory <NUM> may comprise one or more non-transitory, tangible, computer-readable, and/or computer-executable storage media. Examples of memory <NUM> include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), database and/or network storage (for example, a server), and/or other computer-readable medium.

Processor <NUM> may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or all of the described functions of controller <NUM>. In some embodiments, processor <NUM> may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), and/or other logic.

Claim 1:
An apparatus (<NUM>), comprising:
a separator tank (<NUM>) configured to separate a first refrigerant into a vapor component and a liquid component;
a heat exchanger (<NUM>) exposed to a load (<NUM>) configured to use the liquid component of the first refrigerant to remove heat from a space proximate the load (<NUM>), wherein the space comprises at least one of a refrigeration unit and walk-in cooler or freezer;
a compressor-less heat separator (<NUM>) configured to extract heat from the vapor component of the first refrigerant and use electrical power to move the heat to a second refrigerant;
a fluid cooler (<NUM>) configured to remove heat from the second refrigerant;
a temperature sensor (<NUM>) configured to measure a temperature of the second refrigerant; and
a controller (<NUM>) communicatively coupled to the temperature sensor (<NUM>), the controller (<NUM>) configured to:
compare the measured temperature to a temperature set point; and
based on the comparison between the measured temperature and the temperature set point, increase a rate of flow of the second refrigerant to the fluid cooler (<NUM>),
wherein the separator tank (<NUM>) comprises:
a vapor outlet (<NUM>) configured to discharge the vapor component of the first refrigerant to the heat separator (<NUM>);
a liquid outlet (<NUM>) configured to discharge the liquid component of the first refrigerant to the heat exchanger (<NUM>);
a first inlet (<NUM>) configured to receive the first refrigerant from the heat separator (<NUM>); and
a second inlet (<NUM>) configured to receive the first refrigerant from the heat exchanger (<NUM>) exposed to the load (<NUM>);
wherein the separator tank (<NUM>) is configured to use gravity to separate the vapor component and liquid component of the first refrigerant received from the heat exchanger (<NUM>) and the heat separator (<NUM>).