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Cascade Refrigeration
A cascade refrigeration cycle is a multi-stage thermodynamic cycle. An example two-stage process is shown at right. (Bottom on mobile) The cascade cycle is often employed for devices such as ULT freezer An ultra low temperature (ULT) freezer is a refrigerator that stores contents at between . An ultra low temperature freezer is commonly referred to as a "minus 80 freezer" or a "negative 80 freezer", referring to the most common temperature stand ...s. In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used. The evaporation-condensation temperatures of each cycle are sequentially lower with some overlap to cover the total temperature drop desired, with refrigerants selected to work efficiently in the temperature range they cover. The low temperature system removes heat from the space to be cooled using an evaporator, and transfers it to a heat exchanger that is cooled by the evaporation of the refrigerant of the high temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cascade Refrigeration (two-cycle) Process Schematic Diagram
A cascade refrigeration cycle is a multi-stage thermodynamic cycle. An example two-stage process is shown at right. (Bottom on mobile) The cascade cycle is often employed for devices such as ULT freezer An ultra low temperature (ULT) freezer is a refrigerator that stores contents at between . An ultra low temperature freezer is commonly referred to as a "minus 80 freezer" or a "negative 80 freezer", referring to the most common temperature stand ...s. In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used. The evaporation-condensation temperatures of each cycle are sequentially lower with some overlap to cover the total temperature drop desired, with refrigerants selected to work efficiently in the temperature range they cover. The low temperature system removes heat from the space to be cooled using an evaporator, and transfers it to a heat exchanger that is cooled by the evaporation of the refrigerant of the high temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Cycle
A thermodynamic cycle consists of a linked sequence of thermodynamic processes that involve transfer of heat and work into and out of the system, while varying pressure, temperature, and other state variables within the system, and that eventually returns the system to its initial state. In the process of passing through a cycle, the working fluid (system) may convert heat from a warm source into useful work, and dispose of the remaining heat to a cold sink, thereby acting as a heat engine. Conversely, the cycle may be reversed and use work to move heat from a cold source and transfer it to a warm sink thereby acting as a heat pump. If at every point in the cycle the system is in thermodynamic equilibrium, the cycle is reversible. Whether carried out reversible or irreversibly, the net entropy change of the system is zero, as entropy is a state function. During a closed cycle, the system returns to its original thermodynamic state of temperature and pressure. Process quantities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ULT Freezer
An ultra low temperature (ULT) freezer is a refrigerator that stores contents at between . An ultra low temperature freezer is commonly referred to as a "minus 80 freezer" or a "negative 80 freezer", referring to the most common temperature standard. ULT freezers come in upright and chest freezer formats. Application In contrast to short term sample storage at by using standard refrigerators or freezers, many molecular biology or life science laboratories need long-term cryopreservation (including "cold chain" and/or " colder chain" infrastructures) for biological samples like DNA, RNA, proteins, cell extracts, or reagents. To reduce the risk of sample damage, these types of samples need extremely low temperatures of . Mammalian cells are often stored in dewars containing liquid nitrogen at . Cryogenic chest freezers can achieve temperatures down to , and may include a liquid nitrogen backup. Biological samples in ULT freezers are often stored in polymer tubes and microtube ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peltier Cooler
Thermoelectric cooling uses the Peltier effect to create a heat flux at the junction of two different types of materials. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other, with consumption of electrical energy, depending on the direction of the current. Such an instrument is also called a Peltier device, Peltier heat pump, solid state refrigerator, or thermoelectric cooler (TEC) and occasionally a thermoelectric battery. It can be used either for heating or for cooling, although in practice the main application is cooling. It can also be used as a temperature controller that either heats or cools. This technology is far less commonly applied to refrigeration than vapor-compression refrigeration is. The primary advantages of a Peltier cooler compared to a vapor-compression refrigerator are its lack of moving parts or circulating liquid, very long life, invulnerability to leaks, smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermographic Camera
Infrared thermography (IRT), thermal video and/or thermal imaging, is a process where a thermal camera captures and creates an image of an object by using infrared radiation emitted from the object in a process, which are examples of infrared imaging science. Thermographic cameras usually detect radiation in the long-infrared range of the electromagnetic spectrum (roughly 9,000–14,000 nanometers or 9–14 μm) and produce images of that radiation, called thermograms. Since infrared radiation is emitted by all objects with a temperature above absolute zero according to the black body radiation law, thermography makes it possible to see one's environment with or without visible illumination. The amount of radiation emitted by an object increases with temperature; therefore, thermography allows one to see variations in temperature. When viewed through a thermal imaging camera, warm objects stand out well against cooler backgrounds; humans and other warm-blooded animals become ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooling Technology
Cooling is removal of heat, usually resulting in a lower temperature and/or phase change. Temperature lowering achieved by any other means may also be called cooling.ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology The transfer of thermal energy may occur via thermal radiation, heat conduction or convection. Examples can be as simple as reducing temperature of a coffee. Devices *Coolant *Cooling towers, as used in large industrial plants and power stations * Daytime passive radiative cooler *Evaporative cooler *Heat exchanger *Heat pipe *Heat sink *HVAC (Heating, Ventilation and Air Conditioning) * Intercooler *Radiative cooling in Heat shields * Radiators in automobiles *Pumpable ice technology *Thermoelectric cooling *Vortex tube The vortex tube, also known as the Ranque-Hilsch vortex tube, is a mechanical device that separates a compressed gas into hot and cold streams. The gas emerging from the hot end can reach temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryopreservation
Cryo-preservation or cryo-conservation is a process where Organism, organisms, organelles, cell (biology), cells, Biological tissue, tissues, extracellular matrix, Organ (anatomy), organs, or any other biological constructs susceptible to damage caused by unregulated chemical kinetics are preserved by cooling to very low temperatures (typically using solid carbon dioxide or using liquid nitrogen). At low enough temperatures, any Enzyme, enzymatic or chemical activity which might cause damage to the biological material in question is effectively stopped. Cryopreservation methods seek to reach low temperatures without causing additional damage caused by the formation of ice crystals during freezing. Traditional cryopreservation has relied on coating the material to be frozen with a class of molecules termed cryoprotectants. New methods are being investigated due to the inherent toxicity of many cryoprotectants. Cryoconservation of animal genetic resources is done with the intentio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preservation Methods
Preservation may refer to: Heritage and conservation * Preservation (library and archival science), activities aimed at prolonging the life of a record while making as few changes as possible * ''Preservation'' (magazine), published by the National Trust for Historic Preservation * Historic preservation, endeavor to preserve, conserve and protect buildings, objects, landscapes or other artifacts * Conservation and restoration of cultural heritage, protection and care of tangible cultural heritage Mathematics and computer science * Type preservation, property of a type system if evaluation of expressions does not cause their type to change * Case preservation, when computer storage preserves the distinction between upper and lower case * Digital preservation, endeavor to ensure that digital information of continuing value remains accessible and usable Arts and entertainment * ''Preservation'' (2018 novel), historical fiction by Jock Serong about the wreck of the ''Sydney C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Cycles
A thermodynamic cycle consists of a linked sequence of thermodynamic processes that involve transfer of heat and work into and out of the system, while varying pressure, temperature, and other state variables within the system, and that eventually returns the system to its initial state. In the process of passing through a cycle, the working fluid (system) may convert heat from a warm source into useful work, and dispose of the remaining heat to a cold sink, thereby acting as a heat engine. Conversely, the cycle may be reversed and use work to move heat from a cold source and transfer it to a warm sink thereby acting as a heat pump. If at every point in the cycle the system is in thermodynamic equilibrium, the cycle is reversible. Whether carried out reversible or irreversibly, the net entropy change of the system is zero, as entropy is a state function. During a closed cycle, the system returns to its original thermodynamic state of temperature and pressure. Process quantities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Processes
Classical thermodynamics considers three main kinds of thermodynamic process: (1) changes in a system, (2) cycles in a system, and (3) flow processes. (1)A Thermodynamic process is a process in which the thermodynamic state of a system is changed. A change in a system is defined by a passage from an initial to a final state of thermodynamic equilibrium. In classical thermodynamics, the actual course of the process is not the primary concern, and often is ignored. A state of thermodynamic equilibrium endures unchangingly unless it is interrupted by a thermodynamic operation that initiates a thermodynamic process. The equilibrium states are each respectively fully specified by a suitable set of thermodynamic state variables, that depend only on the current state of the system, not on the path taken by the processes that produce the state. In general, during the actual course of a thermodynamic process, the system may pass through physical states which are not describable as thermody ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Systems
A thermodynamic system is a body of matter and/or radiation, confined in space by walls, with defined permeabilities, which separate it from its surroundings. The surroundings may include other thermodynamic systems, or physical systems that are not thermodynamic systems. A wall of a thermodynamic system may be purely notional, when it is described as being 'permeable' to all matter, all radiation, and all forces. A state of a thermodynamic system can be fully described in several different ways, by several different sets of thermodynamic state variables. A widely used distinction is between ''isolated'', ''closed'', and ''open'' thermodynamic systems. An isolated thermodynamic system has walls that are non-conductive of heat and perfectly reflective of all radiation, that are rigid and immovable, and that are impermeable to all forms of matter and all forces. (Some writers use the word 'closed' when here the word 'isolated' is being used.) A closed thermodynamic system is c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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