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  Thermal superconductor refrigeration systemUSPTO Application #: 20070209380Title: Thermal superconductor refrigeration system Abstract: A superconductor refrigeration system incorporates thermal superconducting heat transfer. The system includes an intensifying heat exchanger, a refrigerating heat exchange coil formed from thermal superconductor material, and a dissipating heat exchange coil formed from thermal superconductor material. The system can also include a switch connected to condenser and evaporator heat exchange segments, a refrigeration switch segment and a dissipating switch segment such that in a first switch position a refrigerating mode is provided and in a second switch position a defrost mode is provided. Additional embodiments include thermostat controllers and blowers for enhanced control. Heat exchange and reuse is described for multiple heat exchangers coupled by thermal superconductors. A defrosting element is described for refrigeration heat exchangers. (end of abstract)
Agent: Mcandrews Held & Malloy, Ltd - Chicago, IL, US Inventors: Lynn Mueller, John Graham USPTO Applicaton #: 20070209380 - Class: 062260000 (USPTO) Related Patent Categories: Refrigeration, Structural Installation, Geographic, E.g., Subterranean Feature The Patent Description & Claims data below is from USPTO Patent Application 20070209380. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention relates generally to refrigeration systems, and more particularly to a refrigeration heat exchanger having a superconducting heat transfer element. BACKGROUND OF THE INVENTION [0002] Commercial refrigeration systems typically use a phase-change refrigerant to absorb heat from an interior space and move it to an exterior space where it can be rejected. The refrigerant in these typical systems is circulated in a refrigerant loop connecting a refrigerating heat exchanger (or "evaporator") which absorbs heat from a space to be cooled, a compressor which intensifies this heat, and a heat dissipating heat exchanger (or "condenser") which dissipates the heat either into the outside environment or into a building mechanical system that requires heat, such as a domestic hot water system. [0003] In a typical application such as a walk-in freezer with a roof-top heat dissipating heat exchanger, the refrigeration process works in the following manner. Liquid refrigerant flows through the refrigerant loop and into the evaporator where it rapidly drops in temperature as it expands to fill the larger volume of the evaporator, becoming a supercooled partial liquid. As the droplets in the partial liquid contact the inner surfaces of the evaporator coil they absorb heat and rapidly evaporate, cooling the surfaces of the evaporator to a temperature lower than the air in the freezer. The cooled surfaces then absorb heat from the air as it is drawn across the surfaces by a fan. The cooled air then returns to the space, cooling the space. The evaporated refrigerant then flows out of the evaporator, through the refrigerant loop, and into the compressor where it is compressed, causing the heat contained in the vapor to be intensified. The hot vapor then flows through the loop to the roof-top condenser which becomes hot. Air drawn across the outer surfaces of the condenser absorbs this heat and carries it off into the atmosphere. This loss of heat causes the refrigerant vapor to condense into a liquid. The liquid refrigerant then flows back to the evaporator to begin the heat removal process again. [0004] Many variants of this process have been developed to serve different refrigeration requirements, but the process remains similar. In some systems, the roof-top heat dissipating heat exchanger is replaced with a heat exchanger inside the building, with air ducts coming into and going out of the building for the purpose of rejecting heat into the outside atmosphere. In other systems, the roof-top heat exchanger is replaced with a refrigerant-to-water heat exchanger inside the building, which transfers heat from the refrigerant loop to a water loop, such that heat can be rejected into an outdoor evaporation pond or employed by a building mechanical system to provide hot water for space heating or domestic hot water purposes. Similarly, the refrigerating heat exchanger can absorb heat from a liquid such as water in an ice making machine instead of from the air in a space. In these variations, the method of heat exchange at the refrigerating and dissipating heat exchangers varies, but the refrigeration circuit remains the same. Typically, the characteristic rating of the refrigerant is matched to the application. [0005] In large refrigeration systems, this process has a number of inherent problems and inefficiencies. [0006] Commercial refrigerators are often large and far away from the refrigeration plants that serve them, so the loops are often very long and have large volumes of refrigerant and large numbers of connections and valves, which makes them vulnerable to leaks and causes them to require frequent maintenance of components. [0007] The complexity of large circulating refrigerant systems makes it difficult for the heat absorbed in one refrigerator to be employed to defrost the heat exchanger in another or to supplement other building mechanical systems requiring heat. This results in low energy efficiency. [0008] The movement of refrigerant over long distances requires significant pumping energy, which decreases system energy efficiency. [0009] In the refrigeration cycle, cold refrigerant passes through loops in the evaporator, absorbing heat from the evaporator as it passes through. As a result, each loop naturally has a temperature gradient--colder at the refrigerant inlet and warmer at the refrigerant outlet. This means that parts of the evaporator are warmer than others, making them less able to absorb heat from the air, resulting in lower evaporator efficiency, and requiring an increase in heat exchanger size to compensate. [0010] In air-to-refrigerant heat exchangers operated in the refrigeration mode, the cooling process causes moisture from the air to condense and freeze on the surfaces of the closely packed fins and tubes that make up the evaporator. Eventually this ice build-up blocks air-flow through the evaporator, reducing efficiency. When efficiency drops below an acceptable level, the ice is removed through a defrost cycle, most commonly achieved by reversing the refrigeration system to provide heating instead of cooling to the refrigerating heat exchanger. [0011] Defrosting results in three problems. First, the reversing valves employed to reverse the flow of refrigerant in the system are inefficient and prone to failure. Second, the reversal of the system from refrigeration to defrost causes refrigerant to behave differently from it's prior phase at a location in the loop, condensing where it previously evaporated, evaporating where it previously condensed; compensating for these changes in behavior requires additional system complexity, cost and maintenance. Second, frequent cycling from cold to hot causes stress on connections which causes leaks. Third, the defrost cycle requires the whole refrigeration system to be stopped, gradually reversed to decrease heat stress, operated in reverse long enough to defrost the refrigerating heat exchanger, stopped, and then gradually reversed to decrease heat stress before returning to the refrigerating mode; this creates a transition time, and during this time the space is not being refrigerated, leading to a rise in space temperature that can be compensated for with high levels of refrigeration energy when the refrigeration mode becomes operational again, causing the whole refrigeration system to require higher refrigerating capacity. Other systems have been developed to achieve shorter defrost times but each has inherent problems. Electrical resistance strip heaters for example, have been mounted to the face of evaporator coils, allowing the primary refrigeration system to simply stop while the secondary electrical system provides defrost energy. These strip heaters are prone to burning out, requiring frequent replacement which can be done if the strips are mounted to the accessible face of the evaporator unit. This causes them to be inefficient because they are far away from the ice mass, which at the core of the evaporator. [0012] There is a need for a refrigeration system that operates without a refrigerant transfer loop, utilizes much less power than conventional refrigerators, has smaller heat exchangers, has an extended lifetime due to fewer parts, uses less refrigerant, has a shorter and more efficient defrost cycle and provides enhanced refrigeration efficiency per unit power. There is further a need for a non-refrigerant based defrosting element for use in combination with a conventional refrigeration system. SUMMARY OF THE INVENTION [0013] A refrigeration system incorporates thermal superconducting heat transfer. The system includes an intensifying heat exchanger, a refrigerating heat exchange coil formed from thermal superconductor material, and a dissipating heat exchange coil formed from thermal superconductor material. The system can include a switch connected to condenser and evaporator heat exchange segments, a refrigeration switch segment and a dissipating switch segment such that in a first switch position a refrigerating mode is provided and in a second switch position a defrost mode is provided. Additional embodiments include thermostat controllers and blowers for enhanced control. Heat exchange and reuse is described for multiple heat exchangers coupled by thermal superconductors. A defrosting element is described for refrigeration heat exchangers. [0014] In one embodiment, a refrigeration system having thermal superconducting heat transfer includes a reversible intensifying heat exchanger, having a compressor, a refrigerating heat exchange coil formed from thermal superconductor material, and a dissipating heat exchange coil formed from thermal superconductor. The refrigeration system also has a reversing valve that can be configured to provide corresponding refrigerating or defrosting modes of the superconductor refrigeration system. The refrigerating or defrosting modes can be selected by a thermostat controller for the purpose of operating in a refrigerating or defrosting mode to refrigerate a space. [0015] In a further embodiment, a defrosting system having thermal superconducting heat transfer includes an intensifying heat exchanger, a defrosting heat exchange coil formed from thermal superconductor material, an absorbing heat exchange coil formed from thermal superconductor material, and a controller programmable to a desired set point and further having a thermostat controller connected to the thermal switch and compressor. [0016] In a further embodiment, a superconductor refrigeration exchange element includes a plurality of evaporator refrigerant conduits suitable for receiving refrigerant; an evaporator coupled to ends of each of the plurality of refrigerant coils, a condenser conduit coupled to opposing ends of each of the plurality of refrigerant coils; a plurality of cooling plates formed of a thermally conductive material arranged in a approximately co-planar stack, and having at least one conduit opening through each of the plates corresponding to each refrigerant conduit such that the conduits are seated in thermal contact within the cooling plate stack for the purpose of exchanging heat with air; a thermal superconductor heat transfer pipe arranged such that a coupling portion is coupled on at least one side of the cooling plate stacks such that thermal contact is created between the cooling plates and the heat transfer pipe. The location of the coupling portion relative to the seated conduits is arranged to increase available air flow through the plates, and a transfer portion extends away from the stack of plates. In addition, insulation surrounds at least part of the extended transfer portion to reduce heat transfer loss. Heat is transferred from the cooling plates by the refrigerant conduits for the purposes of cooling the air flow and heat is transferred to cooling plates by the thermal superconductor heat transfer pipe for defrosting ice build up on the cooling plates such that the air flow is approximately maintained. BRIEF DESCRIPTION OF THE DRAWINGS [0017] FIG. 1a is a schematic diagram of a refrigeration system with thermal superconductor heat exchangers and a reversible superconductor transfer switch enabling the system to switch from refrigeration to defrost. FIG. 1b is an enlarged view of the intensifier heat circuit. [0018] FIG. 2 is a schematic diagram of a refrigeration and defrost system with thermal superconductor transfer segments coupled to a heat intensification circuit by independent thermal transfer switches. [0019] FIG. 3 is a schematic diagram of a refrigeration and defrost system with multiple thermal superconductor heat exchangers coupled with independent thermal transfer switches to a single heat intensification circuit. [0020] FIG. 4 is a schematic diagram of a refrigeration and defrost system using a liquid heat exchanger as a heat source or heat sink. Continue reading... Full patent description for Thermal superconductor refrigeration system Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Thermal superconductor refrigeration system patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. 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