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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 freezers. 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 temperature system. Alternatively, a liquid-to-liquid or similar heat exchanger may be used instead. The high-temperature system transfers heat to a conventional condenser that carries the entire heat output of the system and may be passive, fan, or water-cooled. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cascade Refrigeration (two-cycle) Process Schematic Diagram
Cascade, or Cascading may refer to: Science and technology Science * Air shower (physics), a cascade (particle shower) of subatomic particles and ionized nuclei **Particle shower, a cascade of secondary particles produced as the result of a high-energy particle interacting with dense matter * Cascade, the CRISPR-associated complex for antiviral defense (a protein complex) * Cascade (grape), a type of fruit * Cascade waterfalls, or series of waterfalls * Biochemical cascade, a series of biochemical reactions, in which a product of the previous step is the substrate of the next * Collision cascade, a set of nearby adjacent energetic collisions of atoms induced by an energetic particle in a solid or liquid * Ecological cascade, a series of secondary extinctions triggered by the primary extinction of a key species in an ecosystem * Energy cascade, a process important in turbulent flow and drag by which kinetic energy is converted into heat * Trophic cascade, an interaction that can o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Cycle
A thermodynamic cycle consists of linked sequences of thermodynamic processes that involve heat transfer, transfer of heat and work (physics), work into and out of the system, while varying pressure, temperature, and other state variables within the system, and that eventually returns the thermodynamic system, 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 stat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ULT Freezer
An ultra low temperature (ULT) freezer is a refrigerator that stores contents at . 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 "Cold chain#Uses, 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 Cryogenic storage dewar, dewars containing liquid nitrogen at . Cryogenic chest freezers can achieve temperatures down to to and may include a liquid nitrogen backup. Biological samples in ULT freezers are often stored ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peltier Cooler
Thermoelectric heat pumps use the thermoelectric effect, specifically the Peltier effect, to heat or cool materials by applying an electrical current across them. 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 since heating can be achieved with simpler devices (with Joule heating). Thermoelectric temperature control heats or cools materials by applying an electrical current across them. A typical Peltier cell absorbs heat on one side and produces heat on the other.L. E. (2008). Cooling, heating, generating power, and recovering wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermographic Camera
Infrared thermography (IRT), thermal video or thermal imaging, is a process where a Thermographic camera, 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 electromagnetic radiation, 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 Planck's law of black-body radiation, radiation law, thermography makes it possible to see one's environment with or without optical spectrum, 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, war ... [...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. 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, as used in industrial spot cooling See also * Computer cooling * Refridgeration Refrigeration is any of various types of cooling of a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is ejected to a place of higher temperature) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryopreservation
Cryopreservation or cryoconservation is a process where biological material - cells, tissues, or organs - are frozen to preserve the material for an extended period of time. At low temperatures (typically or using liquid nitrogen) any cell metabolism which might cause damage to the biological material in question is effectively stopped. Cryopreservation is an effective way to transport biological samples over long distances, store samples for prolonged periods of time, and create a bank of samples for users. Molecules, referred to as cryoprotective agents (CPAs), are added to reduce the osmotic shock and physical stresses cells undergo in the freezing process. Some cryoprotective agents used in research are inspired by plants and animals in nature that have unique cold tolerance to survive harsh winters, including: trees, wood frogs, and tardigrades. The first human corpse to be frozen with the hope of future resurrection was James Bedford's, a few hours after his c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preservation Methods
Preservation may refer to: Heritage and conservation * Preservation (library and archival science) In Conservation and restoration of cultural property, conservation, Library science, library and archival science, preservation is a set of preventive conservation activities aimed at prolonging the life of a record, book, or object while making ..., 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 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Cycles
A thermodynamic cycle consists of linked sequences 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 processes: (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 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Systems
A thermodynamic system is a body of matter and/or radiation separate from its surroundings that can be studied using the laws of thermodynamics. Thermodynamic systems can be passive and active according to internal processes. According to internal processes, passive systems and active systems are distinguished: passive, in which there is a redistribution of available energy, active, in which one type of energy is converted into another. Depending on its interaction with the environment, a thermodynamic system may be an isolated system, a Closed system#In thermodynamics, closed system, or an Open system (systems theory), open system. An isolated system does not exchange matter or energy with its surroundings. A closed system may exchange heat, experience forces, and exert forces, but does not exchange matter. An open system can interact with its surroundings by exchanging both matter and energy. The physical condition of a thermodynamic system at a given time is described by its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
