Showing papers on "Heat exchanger published in 1989"

Plate type heat exchanger

Abstract: A stacked plate heat exchanger (10) is disclosed which includes heat exchange plates (12,12') arranged in stacked relation, each of the plates including a peripheral flange. Each plate (12,12') includes two types of flow openings (20,22), one type (20) being formed as part of a depression therein, the other (22) being substantially coplanar with the plate surface. The flow openings (20) within the depressions adjoin the coplanar flow openings (22) of the plate positioned immediately therebelow. Additional projections (24) and depressions (28) are formed between the flow openings of each plate to support it against similar projections (24') and depressions (28') formed in adjacent plates. A turbulator (34) is positioned between and helps support each adjoining pair of heat exchange plates (12,12'). Fluid is introduced to the heat exchanger by means of a nozzle (52) having a base portion locked between a top plate (36) and one of the heat exchange plates (12,12').

Design of Cooling Towers by the Effectiveness-NTU Method

Abstract: Developpement de la methode NUT-efficacite pour la conception de tours de refroidissement: introduction de l'enthalpie de l'air sature en parametre et definition du nombre d'increments correspondant a la precision desiree Presentation de la methode LMED (difference d'enthalpie logarithmique moyenne) et comparaison des deux methodes sur des exemples

Unsteady compressible two-phase flow model for predicting cyclic heat pump performance and a comparison with experimental data

Abstract: A dynamic model of vapour compression heat pumps is presented. Due to the importance of thermal expansion and compressibility effects, a detailed mathematical treatment of the condenser, evaporator and accumulator is given. Brief descriptions of the modelling techniques used for the remaining heat pump components and the solution methodology employed in the complete heat pump model are presented. Lumped-parameter models were developed for the expansion device, natural-gas-fueled internal combustion engine and compressor (open and hermetic). Inclusion of an appropriate void fraction model was found to be essential in determining the spatial refrigerant mass distribution, therefore a discussion pertaining to this model is also given. Simulations results and experimental data are favourably compared for transient operation of a hermetic water-to-water heat pump and an air-to-air system with an open compressor. The spatial variations of temperature, enthalpy, mass flow rate and density are predicted at each point in time for the two heat exchangers. The refrigerant pressures in the condenser and evaporator are determined such that the boundary conditions for the governing set of parabolic partial differential equations are satisfied. The summary provides a list of on-going work in the area of heat pump simulation and applications.

Method and apparatus for simultaneous heat and mass transfer

Abstract: A method and apparatus for heat and mass transfer is described that is applicable to: concentration, crystallization, purification, fractionation, stripping, absorption, and/or heat exchange for liquid media; drying for solid or gel media; and temperature and humidity modification for gas media. Generally, using a moving gas, such as air at a constant and atmospheric pressure, a continual change in a vapor-liquid equilibrium is created between proximate but continually changing gas and liquid temperatures within energy transferring chambers. Chamber wetting, implemented segmentedly, allows mass transfer into and from the moving gas. A forced temperature differential in each chamber causes heat transfer between chambers by means of thermally conductive partitions. This transfer can allow condensation causing further evaporation in the opposite chamber resulting in a recycling of energy. Concurrent with temperature variances, the segmented wetting can further allow wetting substance concentrations caused by evaporation, selective condensation, or absorption to vary between wetted sectors. A migratory movement connecting these wetted sectors generally provides for development of applicable concentration gradients between the wetted sectors along the chamber length.

Laboratory apparatus for optional temperature-controlled heating and cooling

Abstract: Laboratory apparatus for optionally heating or cooling samples, comprising a block of one or more Peltier elements which, with one of their thermal poles, are in thermal contact with an essentially rectangular block of heat conducting metal, and with the other pole are in thermal contact with a heat exchanger, this latter being thermally insulated from the metal block. One of the outer surfaces of the rectangular metal block serves as a working outer surface for heating or cooling the samples. All outer surfaces of the metal block, with the excption of the working surface and the surface in contact with the Peltier elements, are thermally insulated. The working surface may be used for heating or cooling at will through the inversion of the direction of the alimentation current for the Peltier elements.

The cascade analysis for energy and process integration of batch processes. I: Calculation of energy targets

Abstract: A time-dependent analysis, the Cascade analysis, is presented. Time-temperature cascade tables are developed which show how much heat can be recovered by direct heat exchange between streams, and how much heat can be transferred between different time intervals by heat storage systems. A three-dimensional cascade plot is introduced to aid visualisation of heat flows. The effects of using different types of heat storage are discussed briefly. Algorithms for generation of the cascades are also presented

Design and Operating Guide for Aquaculture Seawater Systems

Abstract: 1 Introduction 2 Problem Definition and Establishing Requirements Design process Defining objectives Quantifying requirements Production cycle Types of systems System carrying capacity Carrying capacity guidelines Design requirements Constraints 3 Site Considerations Marine conditions Terrestrial conditions Environmental regulations and permitting 4 Seawater Sources Options and considerations Artificial seawater Seawater wells Marine intakes 5 System Layout and Elevation Generic system Elevations and head tanks Intake and pump house considerations Discharge considerations 6 Piping Design and Calculations Major tradeoffs Biofouling control Water hammer Frictional losses in pipes Frictional losses in fittings Open channel flow 7 Pump Selection Pump options Generic centrifugal pump NPSH and dynamic head Matching system and pump 8 Materials Selection Biological constraints Seawater constraints Piping materials Pump materials Marine concrete Problem areas 9 Seawater Flow Control Gravity flow Water level control Control of flow rate Flow measurement 10 Solids Removal Considerations, tradeoffs and options Cartridge filters Diatomaceous earth filters Filter bags Centrifuges and cyclones Sand filters Microscreens Sedimentation 11 Heating and Cooling Setting requirements Heat exchangers Problem areas 12 Aeration and Degassing Aeration system requirements Gravity aerators Submerged aerators Gas supersaturation and degassing 13 Disinfection Considerations and options Chemical compounds Ozone Ultraviolet (UV) radiation 14 Alarm Systems Characteristics and options Alarm points 15 Water Recycling Setting requirements and options Nitrification and biofilters Foam fractionation Activated carbon and ion exchange Algae 16 Wet Laboratory Areas General considerations and tradeoffs Indoor areas Outdoor areas 17 Construction Consideration Construction arrangements Construction cost estimating Design changes Installation of seawater lines Start-up 18 Operational Considerations Operating procedures Assignment of responsibilities Spares and redundancy Preventive maintenance Monitoring and control Operational problem areas 19 Summary Commandments 20 References Appendixes Subject Index

Thermodilution by heat exchange

Abstract: Heat is removed from the blood flow by heat exchange rather than cold-liquid injection; resulting temperature changes are monitored. Flow rate is found from monitored temperature and known parameters related to the amount of heat removed. Preferably heat is removed by pumping cold liquid into a sealed balloon or sheath along a catheter, which is in the blood stream. The balloon acts as a heat exchanger; its design optimizes that function. Temperature can be monitored by a thermistor or other sensor closer to the tip of the same catheter. Alternatively it appears possible to use blood-temperature measurements taken just outside the balloon, or even within the balloon, if the system is calibrated to account for the relation between the blood flow rate and the heat lost from balloon to blood. Heat removal can be either quasi steady-state or cyclical: that is, either heat is removed semicontinuously by a low-temperature-differential exposure and resulting steady-state temperatures observed semicontinuously; or heat is removed periodically in brief high-differential exposures, and temperature changes tracked in defined time periods during or after each exposure. In the latter case, a patient's heat balance can be maintained by alternately adding heat in protracted low-differential exposures.

Thermal performance of a heat storage module using PCM's with different melting temperatures

Abstract: The performance of a heat storage unit consisting of number of vertical cylindrical capsules filled with phase change materials, with air flowing across them for heat exchange has been analyzed. Earlier theoretical models did not consider temperature distribution in the radial direction within the capsules, an assumption that limits their applications for small diameter capsules. The mathematical model developed in this work is based on solving the heat conduction equation in both melt and solid phases in cylindrical coordinates, taking into account the radial temperature distribution in both phases. Heat flux was then evaluated at the surface of the first row of the capsules to determine the temperature of the air leaving that row by a simple heat balance. It was found that such computation may be carried out for every few rows rather than for a single row to minimize computer time. The simulation study showed a significant improvement in the rate of heat transfer during heat charge and discharge when phase change materials with different melting temperatures were used.

Refrigerant recovery, purification and recharging system

Abstract: A system for recovering, purifying and recharging refrigerant in a refrigeration system comprises a refrigerant compressor having an input connected through an evaporator and a recovery control valve to a refrigeration system from which refrigerant is to be recovered, purified and recharged. A condenser is connected to the output of the compressor in heat exchange relation with the evaporator for liquifying refrigerant from the compressor output. Refrigerant liquified in the condenser is fed to a first port of a refrigerant storage container. During a purification cycle, refrigerant is circulated from a second port of the refrigerant storage container in a closed path through a circulation valve and a filter for removing water and other contaminants, and then returned to the first container port. The refrigeration system from which refrigerant has been recovered is evacuated to atmosphere through a vacuum valve. Following such evacuation, the second port of the refrigerant storage container is connected through a recharging valve to the refrigeration of system for feeding refrigerant from the storage container to the refrigeration system, and thereby recharging the refrigeration system for normal use.

Low pressure high heat transfer fluid heat exchanger

Abstract: A fluid heat exchanger for cooling an electronic component having a housing for receiving heat from the electronic component in which the housing has a fluid inlet and an outlet at opposite ends of the housing. The cross-sectional area of the housing for conveying fluid from the inlet to the outlet decreases from the inlet to the outlet thereby reducing pressure drop without sacrificing thermal performance. The cross-sectional area may be decreased by tilting a top of the housing relative to a bottom, or providing a plurality of fins separated by channels in which the cross-sectional area of the channels decreases from the inlet to the outlet.

Hydrogen and carbon dioxide coproduction

Abstract: Pure gaseous hydrogen and liquid carbon dioxide are produced by reacting hydrocarbon in a stream reformer 14 and a shift convertor 28 and passing the effluent from the latter through a four bed hydrogen PSA separator unit 38 and then a carbon dioxide PSA separator unit 48. The carbon dioxide PSA unit 48 produces a hydrogen-rich stream which is recycled to the feed to the steam reformer 14, a carbon dioxide-rich recycle stream which is recycled to the feed to the carbon dioxide PSA unit 48 and a carbon dioxide-rich product stream which is compressed in compressors 62 and 64, partially condensed in heat exchanger 68 and separated in a distillation column 70 to produce a pure liquid CO₂ product. A waste stream from the column 70 is recycled to the feed to the carbon dioxide PSA unit 48. A portion of the carbon dioxide-rich product stream is withdrawn intermediate the compressors 62 and 64 such that its pressure is higher than the operating pressure of the carbon dioxide PSA unit 48 and returned thereto as a cocurrent purge preceding bed regeneration to obtain the carbon dioxide-rich product stream.

Indirect air conditioning system

Abstract: This invention relates to an air conditioning system which utilizes the exhaust air from a conditioned space for the conditioning of the supply air to the conditioned space. The invention comprises a supply air heat exchanger and an exhaust air heat exchanger, where the supply air heat exchanger comprises an air-to-air type exchanger. The exhaust air is conditioned by the exhaust air heat exchanger, which may comprise heating or cooling of the exhaust air using dehumidification or evaporative cooling, for example. The conditioned exhaust air is then passed through the supply air heat exchanger so as to condition the supply air. One advantage of the invention is the indirect heat transfer from the exhaust air to the supply air, where any processes that may effect the quality of the exhaust air is not transferred to the supply air, since all or a majority of the exhaust air is discharged to atmosphere.

High heat flux compact heat exchanger having a permeable heat transfer element

Abstract: The present invention is directed to a compact heat exchanger having a permeable heat transfer element and an impervious heat transfer element. Fluid passes through the permeable element through passages which are substantially normal to the interface between the permeable and impervious elements. The fluid passes into channels which are provided at or near the interface between the permeable heat transfer element and the impervious element. Heat is transferred between the fluid and the permeable heat transfer element by convection as the fluid flows through the permeable element. Heat is transferred between the impervious element and the permeable element by conduction. The permeable element can be formed from one or more plates which bound one or more passages through which the fluid flows or can be formed from various porous material such as sintered powders, rods and metal foams.

High efficiency heat exchanger

Abstract: A high efficiency deployable heat radiator system for radiating heat generated at a source of heat aboard an orbiting spacecraft or like vehicle is described which comprises a first subsystem for circulating liquid heat exchange medium into heat exchange relationship with the heat source and for conducting vaporous medium generated at the heat source to a manifold; one or more interconnected movable radiator panels each including a pair of spaced wall members defining heat radiating surfaces; a plurality of heat pipes each having an elongated condenser end disposed between wall members of the radiator panels and in heat exchange relationship with the heat radiating surfaces; a manifold for conducting vaporous medium from the source into heat exchange contact with the evaporator ends of the heat pipes; an interface structure interconnecting the evaporator end of each heat pipe with the manifold and including a tubular member enclosing each evaporator end for conducting vaporous heat exchange medium into contact with the evaporator end and conducting condensed heat exchange medium back toward the source of heat; and wherein each heat pipe includes a flexible portion between the interface structure and the first panel and between panels so that the panels may be selectively moved between folded and deployed positions. The evaporator ends of the heat pipes and the inner surface of the tubular members of the interface structure are preferably grooved to promote heat exchange at the evaporator ends of the heat pipes.

Heat exchanger having piezoelectric fan means

Abstract: A fluid heat exchanger (10) for cooling an electronic component (16) including a housing (12) having a fluid inlet (18) and fluid outlet (20) Piezoelectric means (32, 34) are connected to a plurality of flexible blades (30) for pumping fluid from the inlet (18) to the outlet (20) A heat conductive structure is connected to the housing base (12) for conducting heat to the fluid The heat conductive structure may include the flexible blades (30) and/or fixed metal fins (40)

Pinch technology for the synthesis of optimal heat and power systems

Abstract: This paper explains the basics of pinch technology and demonstrates its relationship with Second Law Analysis. It shows that the exergy losses in an optimal design developed by pinch technology are rigorously inevitable. The methods are introduced with reference to heat exchanger networks. The principles are then applied to heat and power systems to enable a parallel treatment

Portable unitary aircraft air conditioner and heater

Abstract: A portable self contained air conditioner which has a platform base (20) with an enclosure (22) attached on top. A recropricating engine (38) is resiliently mounted on the platform with a propeller fan (44) on the front drive and a blower (46) directly attached to the flywheel on the back. A refrigerant compressor (54) is also directly coupled to the engine flywheel with a universal joint drive shaft (56). A drive shaft adapter (60) registers to the flywheel on one end and to the drive shaft on the other with the blower impeller (50) sandwiched in between. A vapor cycle refrigerant system provides the cooling effect and an electrical control system furnishes the operational direction. The engine cooling is integral with the refrigeration system utilizing an additional section of the condenser coil (66) and the same air movement supplied by the propeller fan on the engine. The preferred embodiment includes a pair of closely spaced tandem wheels on each side and the internal component location allows a balanced center of gravity for portability. The blower employs a circular outlet at right angles to the plane of the impeller directing the pressurized air to exit at 90 degrees to the plane of the blower. Optional heating is supplied by a hydraulic system in conjunction with jacket water from the engine heating the conditioned air stream.

Effect of frost growth on the performance of louvered finned tube heat exchangers.

Abstract: An experimental investigation of the effects of frost growth on the performance of heat exchangers with louvered fins has been conducted. Frost accumulation, pressure drop across the heat exchanger and an energy transfer coefficient based on a logarithmic mean enthalpy difference (LMED) were quantified under frosting conditions as functions of the air humidity, air face velocity and fin spacing. Higher air humidity, air face velocities and smaller fin spacing all led to increased frost growth, higher pressure drops and higher energy transfer coefficients. As frost accumulated on the heat exchanger, the overall energy transfer coefficient eventually dropped. These trends are consistent with those reported in the literature.

Apparatus and method for optimizing the air inlet temperature of gas turbines

Abstract: A heat exchanger is disclosed for heating air entering a combustion gas turbine to increase the power output of the turbine when the turbine operates in a cold environment. The heat exchanger may be used also as a cooler to cool air entering the turbine to increase the power output of the turbine when the turbine operates in a hot environment.

Ericsson cycle machine

Abstract: An Ericsson cycle machine is disclosed which can be used for refrigeration, liquefaction of nitrogen or as an engine. The invention includes a liquid ring compressor linked to a liquid ring expander by a gas loop that includes a recuperator. As a refrigeration unit, the liquid ring in the compressor is channeled through a heat exchanger to reject waste heat and liquid is tapped from the expander liquid ring and used as a refrigerant.

Multipass plate heat exchangers -- Effectiveness-NTU results and guidelines for selecting pass arrangements

Abstract: Plate heat exchangers are classified on the basis of number of passes on each side and the flow arrangement in each channel, taking into account the end plate effects. This results in four configurations each for the 1-1 (1 Pass-1 Pass), 2-1, 2-2, 3-3, 4-1, 4-2, and 4-4 arrangements, and six configurations for the 3-1 arrangement. These arrangements are analyzed using the Gauss-Seidel iterative finite difference method; the plate arrangement that yields the highest effectiveness in each pass configuration is identified. Comprehensive results are presented in tabular form for the temperature effectiveness P{sub 1} and log-mean temperature difference correction factor F as functions of the number of transfer units NTU{sub 1}, the heat capacity rate ratio R{sub 1}, and the total number of thermal plates. On the basis of these results, specific guidelines are outlined for the selection of appropriate plate heat exchanger configurations.

Attic solar energy vehicle

Abstract: The "unmodified" roof (32) and "unmodified" attic (34), of a residential or similar building, are used in conjunction with an "attic based" air to liquid forced air heat exchanger (46) to form an active "attic solar energy vehicle". This solar (30) based system is used to heat swimming pools, spas, hot tubs, domestic hot water and in providing space heating/cooling and in cooling overheated swimming pools or other bodies of water--in a cost efficient way. Low operating cost forced air convection principles that make use of the temperature differentials present are applied. The "unmodified" roof (32) functions as a massive solar (30) collector. The "unmodified" attic (34) functions as a heat transfer and storage medium. The forced air to liquid heat exchanger (46) takes hot attic (34) air directly off of the interior of the roof structure (32) and transfers it to water or other liquid. When used for swimming pool (76) heating, the "attic solar energy vehicle" can save 90% of the fossil fuel normally required to heat swimming pools (76). In addition, an active solar energy system is presented without the corresponding problems associated with roof (32) mounted solar panel systems.

Asymptotic Effectiveness-NTU Formulas for Multipass Plate Heat Exchangers

Abstract: Journal of heat transfer proceedings published by ASME. Please see www.ASME.org for the complete proceedings.

Multi-stage boiler/regenerator for liquid desiccant dehumidifiers

Abstract: An improved method and apparatus for regenerating aqueous desiccants for use in an air conditioning system are disclosed. The disclosed method and apparatus utilizes a gas-fired desiccant boiler and a combined desiccant regenerator/interchange heat exchaner. The combined regenerator/heat exchanger utilizes steam produced from the boiler to provide heat for partial regeneration. The desiccant boiler has a liquid/vapor separator chamber and thermosyphon recirculation to reduce scale and corrosion of the boiler.

Mobile system for deicing aircraft

Abstract: A deicing system for applying a deicing mixture to an aircraft is provided. Water is enclosed in a first tank, and deicing fluid in a second tank. A first pump transfers water through a heater, to a heat exchanger located in the second tank. The deicing fluid is thereby heated to a desired operating temperature by the hot water flowing through the heat exchanger, with the flow of hot water controlled by a heater control device. The first pump and second pump transfer heated water and heated deicing fluid, respectively, to a mixing chamber. A mixing control means controls the respective flows to provide the desired mixture. The mixture of water and deicing fluid is then applied to the aircraft via a nozzle.

Inductor transformer cooling apparatus

Abstract: Plate fin heat exchangers (11, 12 or 34, 35, 36) for transformers (10) and inductors (30) made of laminated iron cores (16 or 44) and insulated wire coils (13, 14, 15 or 45, 46, 47, 48) placed around the legs of the cores (16 or 44) are provided in the form of a plate fin between the coils of wire. The wire coils (13, 14, 15 or 45, 46, 47, 48) and respective heat exchangers (11, 12 or 34, 35, 36) are sandwiched together with the leg of the iron core (16 or 44) passing through the sandwich. The heat generated in the coils is in direct contact with the surface of the heat exchangers (11, 12 or 34, 35, 36). A narrow air gap (28 or 49) is incorporated in each of the plate fin heat exchangers (11, 12 or 34, 35, 36) at the core leg of each coil (13, 14, 15 or 45, 46, 47, 48) to reduce the path eddy currents can travel and thereby reduce eddy current losses which reduce the power of the transformer (10) or inductor (30).