Showing papers on "Heat exchanger published in 1982"

Second-Law Analysis in Heat Transfer and Thermal Design

Abstract: This review is devoted to the introduction of second-law analysis in heat transfer and entropy generation minimization in thermal design. The presentation proceeds from the derivation of the Gouy-Stodola theorem, the basis for entropy generation minimization in the conceptual design of heat transfer equipment. Appropriate analytical tools, such as the entropy generation number, are devised for the task of estimating the destruction of available work in the processes involving heat transfer. However, the entropy generation number concept is considerably more general, since it can be used to quantitatively describe the degree of irreversibility of engineering components and processes which do not draw their irreversibility solely from heat transfer. The examples considered in this article range from the irreversibility associated with some of the most fundamental convective heat transfer processes to the minimum irreversibility design of one-dimensional insulations such as the main counterflow heat exchanger of a helium liquefaction plant.

A simulation model of the transient performance of a heat pump

Abstract: This paper describes a heat pump transient analysis computer program (TRPUMP). It is based upon component mathematical models in lumped parametric form. It uses first-order differential equations to describe single- and two-phase heat, mass and momentum transfer, and builds upon seven component sub-routines for the dynamic responses of electric motors, compressors, shafts, electric fans, air/refrigerant heat exchangers, accumulators, and thermostatic expansion valves. The model is capable of simulating dynamic responses of the air-to-air heat pump of the type commonly used in residential applications today. Confidence in the model's accuracy has been established by comparison of simulation results with test data taken at the NBS laboratories.

Personal temperature control system.

Abstract: A personal temperature control system for sustaining normal body temperatures in environments with extreme temperatures including a first heat exchanger (10) adapted to be worn as a garment and a second heat exchanger (18) adapted to interact with a temperature source, the first and second heat exchangers being interconnected through a pump (26) and reservoir (28) unit. The first heat exchanger together with the pump and reservoir are portable and in one embodiment the second heat exchanger is constructed to be fully portable. Specific devices including automatic quick release couplings (24) interconnect the first heat exchanger to the second heat exchanger through the pump and reservoir. The fabrication of the first heat exchanger in helmet and vest portions is disclosed together with a control display unit housing (30) the pump and reservoir and including an adjustable flow valve (150) connected in parallel with the second heat exchanger. A preferred embodiment of the adjustable flow valve provides nonlinear change in rate of flow upon adjustment.

A Theoretical Model for Fluid-Elastic Instability in Heat Exchanger Tube Bundles

Abstract: A simple theoretical model has been developed from first principles for the fluidelastic instability in heat exchanger tube bundles. A series of experiments were conducted to verify the basic assumption that only a single tube need be modeled in a flow channel which preserves the basic geometry of the array. The mechanism of instability is found to be one of flow redistribution due to tube motion and a phase lag resulting from fluid inertia. Quite good agreement is found with available experimental data for a parallel triangular array without the need for empirical fluid force coefficients. The model includes the effects of tube array pattern and pitch.

Heat exchanger antifoulant

Abstract: Disclosed is a process for reducing the fouling in a heat exchanger in which a hydrocarbon stream is heated or cooled as it passes through the heat exchanger. From 1 to 500 parts per million of an alkylamino alkylphenol is added to the stream to reduce fouling.

Convection food heating

Abstract: Disclosed are an improved method and apparatus for convection heating which enables rapid heating of foods to obtain a fried taste, texture and appearance without using large amounts of oil or encountering the other disadvantages of frying. According to a preferred embodiment of the apparatus which performs the disclosed method, a cooking chamber is provided having a reservoir at the bottom capable of holding cooking oil or other liquid heat exchange medium. The oil is continuously dispersed into the heating chamber which is preferably closed and sealed as a convective air flow is established within the heating chamber by either rotating a foraminous support which holds the food or by causing a positive flow of air within the chamber by means of air circulating means. Because the heat transfer capability of the convective heating is improved by maintaining a dispersion of liquid heat exchange medium within the air, the heating capability of the apparatus is improved as compared with conventional convective heating. Because of the intimate contact of the hot oil and the rapid cooking, a characteristic fried texture and flavor is achieved. And, because the oil or other liquid cooking medium is employed as a dispersion which can be recirculated according to the preferred embodiments, the amount of cooking oil required according to the invention is much less than in conventional frying operations.

System for efficiently exchanging heat with ground water in an aquifer

Abstract: A method and means for using ground water in an aquifer as a heat source and heat sink are disclosed wherein heat is exchanged between the uniform temperature ground water and heat-exchanging apparatus at the earth's surface through a single well bore. The ground water is exchanged between an upper and lower portion of the aquifer, alternatively depending on the operating mode, in such a manner that a stratified lateral flow of the water after heat exchange is produced following natural convective paths in the top or bottom of the aquifer and resulting in wide laminar dissipation of the altered temperature water while avoiding thermal mixing between that water and the remaining uniform temperature water in the aquifer. This manner of exchange provides a continuous flow of heating or cooling water at or near the ambient aquifer temperature without any depletion of the aquifer. Embodiments are described wherein the aquifer water is brought to the earth's surface and wherein a separate heat-exchanging fluid is circulated between the aquifer and the earth's surface, and modifications are also disclosed involving a valved plenum device for use with the former embodiments and whereby the aquifer may be used to store solar heat.

Exhaust gas treatment method and apparatus

Abstract: Exhaust gas treatment method and apparatus extract heat from an exhaust gas by operating in a water-condensing mode which allows more heat to be recovered, removes particulate matter and condensed acid from the exhaust gas, and washes heat exchange surfaces to keep them clean and wet to improve heat transfer. Systems for heating water, air, and both water and air are disclosed. Methods of constructing and assembling improved heat exchangers are disclosed.

Method and apparatus for monitoring and diagnosing peripheral blood flow

Abstract: A heat exchanger changes the temperature of a predetermined area of the skin at a programmed rate preferably by cooling. The rate at which the area of skin changes in response to temperature change of the heat exchanger and the rate the skin temperature returns to normal are then measured and compared to standard rates over a number of cycles. Impaired peripheral blood flow is evident especially on subsequent cycles as vascular disease slows the rate of return to normal temperature of the skin. The heat exchanger has a cooling chamber with one side of the chamber being a cooling surface adjacent to the skin. An injector is connected to a source of fluid having a boiling point at ambient pressure less than the temperature to which the skin is to be cooled and greater than ambient temperature of the apparatus. The injector injects fluid into the chamber and onto the side of the cooling surface opposite the skin to boil the fluid on the surface to cool the surface and the skin.

Cooling apparatus for a closed housing

Abstract: A cooling apparatus for a housing which is provided with an opening at the upper part thereof, comprises a casing located on the upper part of the housing and including a bottom plate to close the opening and a chamber, a partition wall provided in the casing to divide the chamber into a first chamber section and a second chamber section, heat exchanger including at least one heat pipe provided in the casing through the partition wall with coolant therein for exchanging heat in the first chamber section with heat in the second chamber section. The heat pipe has one end portion in the first chamber section and the other end portion in the second chamber section, and inclines with the one end portion located lower than the other end portion.

Multidimensional numerical modeling of heat exchangers

Abstract: A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchanges for liquid metal services. For the shellside fluid, the conservation equations of mass, momentum and energy for continuum fluids are modified using the concept of porosity, surface premeability and distributed resistance to account for the blockage effects due to the presence of heat transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, heat transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phased on the shell side and may undergo phase-change in the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reaction (LMFBR) intermediate heat exchanges (IHX) and steam generators (SG). The analytical model predictions are compared with three sets of test data (one for IHX and two for SG) and favorable results are obtained, thus providing a limited validation of the model.

Gas turbine power plant

Abstract: The present invention relates to a gas turbine power plant wherein the gas turbine is driven by gases and steam heated indirectly through a heat exchanger by the burning of corrosive fuels. One of the main improvements in the present invention is to utilize a state-of-the-art gas turbine in the power plant.

Vapor compression distillation system

Abstract: A vapor compression distillation system for distillation of any two-component liquid mixture where separation of the more volatile from the less volatile component is required. This system achieves a very high efficiency through the use of vapor compression in conjunction with three heat exchangers: a reboiler which condenses the hot vapors compressed by a vapor pump and uses the heat given up by the condensing vapor to boil bottoms liquid to produce vapor within the stripper, a distillate heat exchanger which recovers heat from the distillate stream, and a bottoms heat exchanger which recovers heat from the outgoing bottoms effluent. This particular component configuration and process results in an exceptionally stable and reliable operation requiring the continuous control of only one parameter, reboiler temperature, while fixing all other process variables. Reboiler temperature is controlled by the use of a heating element which is controlled to give a continuously variable output to assist in preserving stable equilibrium. This close control of the reboiler temperature results in precise control of the operating pressure within the system. This distillation system has several additional features which help its overall energy efficiency and operational stability, including a disengagement section between the reboiler and the stripper, a float chamber to maintain backpressure on the high pressure side of the system, a standpipe assembly for maintaining a liquid filled condition in the bottoms heat exchanger while providing continuous flow for best heat recovery, an optional system for recovery of vapor pump lubricating oil to allow reuse and to prevent fouling of the reboiler heat exchange tubes, and an optional system for cooling the vapor pump by injecting liquid distillate into the pump outlet.

Method and apparatus for producing sterile slush ice

Abstract: A method and refrigeration apparatus for producing a sterile slush ice from a sterile liquid for use in surgical procedures. The refrigeration apparatus includes a cabinet having a heat transfer basin at the top and refrigeration mechanism in the cabinet for cooling the heat transfer basin. A separate sterile product basin is positioned in the heat transfer basin and cooled through a heat transfer medium in the product basin. A sterile liquid is deposited in the product basin and ice is scraped off the walls of the product basin with a sterile scraper. A sterile cover including a liquid impervious cover sheet is provided for covering the heat transfer basin and the heat exchange medium therein and the upper portion of the refrigeration apparatus.

Multidimensional numerical modeling of heat exchangers

Abstract: A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchanges for liquid metal services. For the shellside fluid, the conservation equations of mass, momentum and energy for continuum fluids are modified using the concept of porosity, surface premeability and distributed resistance to account for the blockage effects due to the presence of heat transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, heat transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phased on the shell side and may undergo phase-change in the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reaction (LMFBR) intermediate heat exchanges (IHX) and steam generators (SG). The analytical model predictions are compared with three sets of test data (one for IHX and two for SG) and favorable results are obtained, thus providing a limited validation of the model.

Waste water heat recovery apparatus

Abstract: Waste water heat transfer apparatus (10) is disclosed in which the waste hot water from residential or commercial uses such as washing, etc., is passed into a separate drain (24) and then into a heat exchanger (17) which includes a waste water conduit (40) therein, and then to the sewer drain (29). A supply water conduit (70) extends through the heat exchanger (11) generally paralleling the waste water conduit (40) and has fresh water run therethrough in a direction opposite to that of the flow of waste water to an outlet end, after which the supply water is provided to a water heater (20). The heat exchanger interior is filled with a heat transfer liquid (39), and is so divided by baffles (75, 76) that a temperature gradient is formed in the heat transfer liquid adjacent to the waste water conduit (40), with the liquid being warmest adjacent the inlet (68) of the waste water conduit and decreasing in temperature toward the outlet (69) of the conduit. The supply water, flowing in the opposite direction to that of the waste water, has its lowest temperature at its inlet end (71), which is adjacent the lowest temperature heat transfer liquid, and encounters progressively warmer adjacent heat transfer liquid as it rises upwardly in the heat exchanger toward its outlet end (72). A substantially constant temperature differential is therby maintained throughout the heat exchanger between the waste water within the waste water conduit and the adjacent heat transfer liquid, and between the supply water in the supply water conduit and the adjacent heat transfer liquid. The transfer of a portion of the heat contained in the waste water to the supply water reduces the amount of energy that must be consumed by the water heater, and the system may also be tied to a hot water space heater (45) for a home or other building to preheat the water supplied to the boiler and thereby reduce the energy demand for space heating purposes.

Air conditioning apparatus

Abstract: Air conditioning apparatus comprises a chiller 10, a heat exchanger 11 connected across the outputs of the chiller 10 and disposed in an air duct 12, an air cooling tower circuit, generally indicated at 13, for cooling the chiller 10 and connectable by pipes 14 and 15 and valves 16 and 17 to supply cooling liquid to the heat exchanger 11. A filter 21 is located in the system to clean water flowing from the air cooling tower 20. Provision is made for back washing the filter 21. Various constructions of the filter 21 and its filter elements are described.

Heat exchanger for air conditioning system

Abstract: In a heat exchanger for an air conditioning system including a plurality of heat exchanger tubes and a plurality of fins secured to outer surfaces of the heat transfer tubes, the fins are of a special constructional form, such as slitted fins having slits formed in flat or convoluted fins or spine fins, and the heat transfer tubes are each formed on its inner wall surface with spiral grooves or two systems of spiral grooves of large number. The heat transfer tubes define therein a refrigerant passage while the adjacent two fins define therebetween an air passage extending past the outer surfaces of the heat transfer tubes.

Heat Exchangers-Thermal-Hydraulic Fundamentals and Design

Abstract: (1982). Heat Exchangers-Thermal-Hydraulic Fundamentals and Design. Nuclear Technology: Vol. 58, No. 3, pp. 556-556.

Solid oxide electrochemical energy converter

Abstract: Solid oxide electrochemical energy converters are capable of generating electricity from gaseous chemical fuels as well as producing fuels while consuming electricity. The converters consist of electrochemical cell stacks and heat exchanger stacks. An electrochemical cell stack comprises alternating solid oxide electrolyte plates and electrical conductor plates to form a electrically connected package. Means are provided to direct gases to the surfaces of the electrolyte plates where the electrodes perform the energy conversion. The heat exchanger stack consisting of multiple layers of ceramic or metal plates provides temperature conditioning on incoming reacting gases.

Heat exchanger having uniform surface temperature and improved structural strength

Abstract: A plate-type heat exchanger having uniform surface temperature and improved structural strength is disclosed, which may be used as a structural support member for an object to be temperature controlled, and which provides a surface having an exceptionally uniform temperature for either heating or cooling the object. The heat exchanger includes a fin pad and a machined plate having a fluid passage therein, as well as other structural frame and support members. The major circuit flow direction of the fluid in the passage is perpendicular to the major longitudinal fin direction of the fin pad in the preferred embodiment. All components of the heat exchanger are of material having good thermal conductivity and structural strength, and the components are brazed or otherwise secured together to provide good thermal conductivity and structural reinforcement throughout.

Thermal Energy Storage in Phase Change Material.

Abstract: : The present study deals with an experimental investigation of low temperature thermal storage based on macroencapsulation of Phase Change Material (PCM). The storage performance capabilities of capsule bed, tube bank and tubular single-pass heat exchanger are compared. The tests are conducted on the VKI Solar Utility Network (SUN) which is a closed loop facility designed to study air heating systems. An original data acquisition chain based on two conversing microprocessors is developed to carry out mass flow, pressure drop and temperature measurements. The experimental results are interpreted on the basis of comparison with numerical predictions and they allow to draw the following conclusions. Each type of matrix has its own range of operation for practical application but from a heat transfer standpoint, the PCM capsule packing unit is strongly recommended. It is suggested to extend this investigation to the effect of Reynolds number to find optimum range for thermo-mechanical efficiency.

Fluid catalyst regeneration apparatus

Abstract: A catalyst regeneration process and apparatus for the oxidative removal of coke from a coke contaminated fluid catalyst. The process comprises a high temperature coke combustion zone, a catalyst disengagement zone and an external heat removal zone comprising a shell and tube heat exchanger. Catalyst is cooled by passing it through the shell side of the heat exchanger with a cooling medium through the tube side. A mixture of coke contaminated catalyst, oxygen containing gas, and cool regenerated catalyst from the heat removal zone are contacted in the high temperature combustion zone, the temperature of which is controlled by adjusting the rate at which fluidizing gas is passed to the bottom portion of the shell of the heat exchanger which varies the degree of turbulence of the fluidized bed in the shell side and thus the heat transfer coefficient at the outside surface of the tubes which in turn varies the quantity of heat transferred to the cooling medium in the tubes.

Combination microwave/convection and broiling oven

Abstract: An oven is disclosed combining microwave, infrared and convection cooking. The oven includes in addition to a magnetron, a pair of quartz infrared lamps and a rotatable heat exchanger/fan. The quartz infrared lamps have blinds which either direct the infrared rays toward the food for broiling, or towards the rotating heat exchanger/fan, which in turn transfers heat to the air and blows it out and down towards the food. The entire oven is maintained at negative pressure to prevent the escape of hot, smoke-filled air into other parts of the oven or the kitchen.

Hydronic antitrust operating system

Abstract: A hydronic type of heating system is operated by a burner control system that relies on measuring the boiler water temperature and comparing the temperature change with a rate of rise set into a burner control means to determine whether the boiler is being properly operated This system allows for heating the boiler water to a sufficient temperature before circulating the water through the heat exchange means to thereby prevent condensation on the outside of the boiler heat exchanger to eliminate rusting