Showing papers on "Heat exchanger published in 1980"

Multi-phase modular comfort controlled heating system

Abstract: A circulating fluid that is heated by a number of gas-fired burner assemblies is used to heat a space either through a hot water system or a forced air heating system. Each burner assembly includes a housing with a heat exchanger mounted therein and a gas burner for heating the fluid which flows through the heat exchanger. The heat exchangers are connected in parallel in a closed loop forced circulation system. A microprocessor based thermostat control compares the temperature in the space heated by the air with a reference temperature. Dependent upon the magnitude of the difference between the temperatures, one or more of the burner assemblies are energized. The burner assemblies are sized such that during most of the heating season only a fraction of the burner assemblies are used. Burner assemblies are cycled on and off as needed to return the temperature to the steady state during the warmer and colder parts of the heating season at least one burner assembly is usually in operation during a majority of the heating season.

Geothermal heating and cooling system

Abstract: The geothermal system for conditioning air includes a heat pump (10) of the liquid-to-air type and an improved heat sink (40) in heat exchange relationship with the subterranean water system of the earth and connected to the heat pump through a liquid circulating system. The heat sink includes an elongate metallic liquid container (41) providing a large amount of surface contact with the earth and of a sufficient length and buried at a sufficient depth to provide a good heat transfer relationship with the subterranean water system of the earth. A liquid inlet conduit (44) communicates with the interior of the upper end of the liquid container (41) and an outlet conduit (insulator tube 45 and return pipe 54) extends longitudinally within the container and thermally insulates the outlet liquid from the liquid in the container. A liquid dispensing tube (75) is provided to periodically dispense liquid into the soil surrounding the container (41) to maintain the soil in a moist state and to thereby increase the thermal conductivity between the container (41) and the surrounding earth and subterranean water system.

An Experimental Study of Falling Liquid Film Breakdown on a Horizontal Cylinder During Heat Transfer

Abstract: In this study, an experimental investigation was conducted with subcooled water film flowing over an electrically heated horizontal cylinder. The combinations of film flow rate and heat flux at which film breakdown occurs (i.e., dry patches appear on the surface) were determined. At the conditions prior to dry patch formation, the heat transfer coefficient was determined as well. The results showed that the heat flux needed to cause a dry patch increases with film flow rate. Also, prior to dry patch formation, the heat transfer coefficient increases with film flow rate. The effects of the tube spacing and the liquid film inlet temperature on the breakdown heat flux and heat transfer coefficient were also studied.

Control and method for defrosting a heat pump outdoor heat exchanger

Abstract: A control and method for defrosting the outdoor heat exchanger of an air source heat pump. A defrost cycle is initiated when ice and frost have accumulated on the outdoor heat exchanger sufficiently such that, as a function of the indoor temperature of a comfort zone, the maximum permissible heat transfer degradation at which the efficiency and reliability of the temperature conditioning system are optimized, has occurred. Heat transfer degradation is determined from the outdoor ambient air temperature and the temperature of either the outdoor heat exchanger, or the compressor suction line. If the temperature of the outdoor heat exchanger or the suction line is less than a predetermined value, a deferred defrost cycle is initiated wherein the defrost cycle starts after a fixed time interval has elapsed. The defrost cycle is terminated when the relative tempratures of the outdoor heat exchanger and the outdoor ambient air indicate that sufficient frost is melted from the heat exchanger to insure adequate time between successive defrost cycles for optimizing the efficiency and reliability of the system, or after a predetermined time interval has elapsed, whichever condition occurs first.

Biomass gasifier combustor

Abstract: The present invention is directed to a biomass gasifier combustor which operates by gasification and combustion of the biomass to produce a clean effluent gas which can be used directly for grain drying or other applications where thermal energy is required. This biomass gasifier combustor burns crop residue clean enough so that the combustion gases can be used directly for grain drying without the need for a heat exchanger to isolate the combustion gases from the drying air. The biomass gasifier combustor includes a screw feeder tube having a screw feeder disposed therein. The screw feeder forces the biomass into a first combustion chamber. Primary combustion of the biomass produces a first combustion gas. A venturi gas pump creates a negative pressure region in the gasifier, drawing the first combustion gas into a second combustion chamber. A secondary combustion takes place, completely oxidizing the organics in the primary combustion gas and producing a clean exhaust gas which can be used directly for grain drying purposes. An improved first chamber includes a manifold section for preventing the biomass from escaping into the secondary combustion chamber, and a variable height grate for allowing the ash product to fall through the holes in the variable height grate. A damper may be provided at the air inlets to control the flow rates or primary and secondary air. A damper may be placed on the exhaust eductor or venturi pump for regulating the thermal output of the system. The level of biomass in the first combustion chamber may also be monitored and automatically controlled.

Passive cooling system

Abstract: A cold bank tank in an enclosure for storing thermal energy in a very small area contains a liquid heat transfer fluid and has a top which is the top of the enclosure and a spaced opposite bottom. An inside heat exchanger extends from the bottom of the tank in the enclosure for cooling warm air in the enclosure rising by natural convection, returning the cooled air to the enclosure and transferring the warm air to the tank wherein it warms the fluid in the tank. An outside heat exchanger outside the enclosure is spaced from the top of the enclosure and coupled to the tank. A plurality of energy storage rods in the fluid in the tank store thermal energy in a very small area. The heat warming the fluid is transferred to the energy storage rods and when the outside temperature decreases below a predetermined magnitude, heat is released from the rods to the liquid fluid and vaporizes the fluid. The vaporized fluid flows upward through piping to the outside horizontal heat exchanger, through the outside heat exchanger, whence its heat is dissipated in the cooler outside air, and the vapor is recondensed and returns by gravity force to the tank via piping thereby storing cold energy in the rods for release when the air in the enclosure is next warmed.

Integrated flue gas processing system

Abstract: A system for processing hot flue gas to remove both gaseous contaminants such as sulfur dioxide and particulate matter such as flyash integrates spray scrubbing apparatus and wet electrostatic precipitation apparatus and provides for the advantageous extraction and utilization of heat present in the flue gas. The integrated system utilizes a spray scrubbing tower and a wet electrostatic precipitator which includes a portion constructed as a cross flow heat exchanger with flue gas saturated with water vapor moving vertically upwards inside tubes arranged in a staggered pattern and ambient air being pulled horizontally across the outside of those tubes to cool the tube walls and thereby remove heat from the flue gas and cause condensation of water vapor on the inside wall surfaces. The condensate washes the electrostatically collected flyash particles down from the inside tube walls. The heat that is extracted from the saturated flue gas may be utilized for flue gas reheat after the wet electrostatic precipitator or for preheating of combustion air to the steam generator boiler.

Combined engine cooling system and waste-heat driven heat pump

Abstract: 0 An improved engine cooling system is combined with a jet-driven heat pump system for utilizing otherwise wasted heat from an engine to produce refrigeration and heating of cabin, charge air and other media without requiring additional shaft power from the engine. In a closed cycle, vaporized refrigerant fluid is conveyed via jet ejectors from the engine cooling jacket at a high pressure and temperature and from refrigerant evaporators at low pressures and temperatures to a radiator/condenser at an intermediate pressure and temperature. The greater portion of condensed refrigerant fluid is pumped back to the engine (boiler) and the balance is throttled into the evaporators (heat exchangers) to produce an evaporative cooling effect. The vapor resulting therefrom is evacuated by the ejectors and returned to the condenser/radiator. In the cooling mode, the engine jacket constitutes the boiler in a Rankine cycle power circuit providing motive fluid power for the jet vapor compressor in a reverse Rankine cycle refrigeration circuit incorporating the heat exchangers as cooling coils. In a heating mode the high pressure vapor is conveyed directly from the engine to the heat exchangers which then serve as condensers to provide condensation heating effects, the partially condensed refrigerant being further condensed in the radiator.

Compact thermoelectric refrigerator

Abstract: A compact thermoelectric refrigerator includes a storage compartment, the lower portion of which is lined with a thin, high-conductivity aluminum liner which functions as an internal heat exchanger. The storage compartment is separated by means of a dividing wall from a compartment containing a thermoelectric module, a low profile, high density external heat exchanger including an extruded high thermal conductivity aluminum base and a plurality of closely spaced high thermal conductivity fins attached to the base by means of thermal epoxy, and a centrifugal fan disposed above the external heat exchanger and driven by a fan motor disposed in a recess in a wall of the thermoelectric refrigerator. Outside air is drawn by the centrifugal fan through an air intake grill located in the upper portion of an end panel and is forced through the fins of the external heat exchanger and out of an air outlet grill located along the lower edge of the end panel. The thermoelectric module is in thermal contact with the lower portion of the side of the aluminum liner, and conducts heat away from the aluminum liner to the external heat exchanger. The thickness and conductivity of the aluminum liner are such that a predetermined temperature gradient exists from one end of the storage compartment to the other end thereof.

Corrugated fin type heat exchanger

Abstract: A heat exchanger has a heat exchanger core comprising a single row of parallel tubes defining therein first series of passages for a first fluid and corrugated fins disposed between and thermally connected to each adjacent pair of tubes to cooperate therewith to define a second series of passages for a second fluid. Each tube is of a generally rectangular cross-section and arranged such that the longitudinal axis of the rectangular cross-section is parallel to the direction on the flow of the second fluid through the heat exchanger. The dimension of each fin as measured in the direction of the flow of the second fluid is within the range of from 12 to 23 mm, the pitch of the corrugated fins is within the range of from 1.5 to 3.3 mm and the dimension of the longitudinal axis of the rectangular cross-section of each tube is not greater than the dimension of each fin as measured in the direction of the flow of the second fluid.

Microprocessor discharge temperature air controller for multi-stage heating and/or cooling apparatus and outdoor air usage controller

Abstract: An air conditioning system furnishing temperature conditioned air to a plurality of zones each of which has its own zone damper controlled by its own space thermostat. The system has an air discharge temperature sensor downstream of the temperature conditioning heat exchanger which is connected to a microprocessor controller for controlling a plurality of stages of temperature conditioning apparatus such as heating or cooling apparatus and a damper motor control for controlling the entry of outdoor air into the system. A reset thermal comfort sensor located in a representative zone or area is connected to the microprocessor controller for varying the controlled temperature of the supplied discharge air by operating the outdoor air damper motor and the multi-stage temperature conditioning apparatus to maintain the best use of outdoor air for cooling and the most efficient operation of refrigeration cooling apparatus by ensuring maximum air delivery to the heat exchangers during the operation of the mechanical cooling apparatus.

Totally enclosed air cooled electrical machines

Abstract: A totally enclosed electrical machine, particularly a high power electric motor, is provided with a plate-type, crossflow, air-to-air heat exchanger which is seated on the frame of the electrical machine. Adjacent plates of the heat exchanger are modular units which define an array of ducts through which the internal air heated by the machine flows in a direction away from the machine. The ducts at opposite ends of the array provide passages for the bi-directional flow of air, such that air which is cooled in the heat exchanger is returned to the opposite ends of the machine. The heat exchanger is provided with a plenum in which air is returned to the end ducts. A baffle in the plenum distributes the air in different amounts, which vary progressively but in opposite senses, to the return ducts which communicate with the opposite ends of the machine thereby equalizing the temperature of the return air supplied to the opposite ends of the machine and providing uniform cooling of the machine. External air is directed through channels between adjacent plates of the heat exchanger, the opposite sides of which define the ducts for the internal machine air. The entire unit can readily be assembled at low cost.

Direct expansion solar collector-heat pump system

Abstract: A solar collector-heat pump heating system which comprises metallic plates which are directly exposed to the ambient atmosphere and which are in direct heat exchange relation with tubes. A compressor receives a heated low-boiling working fluid, e.g., R-22, from the tubes as a vapor, compresses it and delivers it to a condenser. The fluid then passes through a throttling valve where it partially vaporizes, then to the tubes, where vaporization continues, utilizing heat absorbed by the plates from solar radiation, the ambient air, rain, and long-wave infrared radiation. Heat is extracted from the condenser and used for space heating. Preferably, heat storage means, e.g., a tank of water or a body of low-melting salt, are provided. Preferably, the heat-absorbing plates are long and narrow. In one embodiment they are spaced from a diffuse reflective backing and are laterally spaced from each other. In another embodiment they form a siding for a building. When heat storage is provided, the system can also serve for cooling by reversing the flow of the working fluid and rejecting heat through the plates at night.

Environmental control system for aircraft with improved efficiency

Abstract: This invention relates to an airconditioning system to provide environmental control for an aircraft's cabin or cockpit. The system cooling cycle includes in combination: a rotary power supply and a turbomachine which includes a power compressor secured to a power shaft for providing compressed air. The rotary power supply is drivingly coupled to the power shaft to operate at a given speed. An expansion cooling turbine is mounted on a shaft concentric to the power shaft. A power driven fan is provided for directing a source of ambient air to and through a heat exchanger. The power compressor is coupled respectively to the cabin and through the heat exchanger to an input of the expansion cooling turbine to thereby draw air from the cabin and deliver the compressed air to the expansion cooling turbine. The expansion cooling turbine is designed to operate at a different speed than the given speed of the power shaft. In the final portion of the system, the expansion cooling turbine has an output coupled to the cabin to deliver conditioned air, which has been cooled, to the cabin. The system heating cycle relies on heated bleed air mixed with cooled air from the expansion turbine to heat the cabin.

Refrigeration circuit for heat pump water heater and control therefor

Abstract: A refrigeration circuit is disclosed which is operable in each of four distinct modes for the heating or cooling of a space, the production of a heated liquid, or the simultaneous cooling of a space and production of heated liquid. The circuit includes compressor means; indoor, outdoor, and liquid heat exchange means; along with vapor conduit means including first valve means and liquid conduit means including second valve means so as to afford selective operation of the circuit in any one of the aforementioned modes. A significant feature of the invention lies in the fact that, during operation in any particular mode, the inactive heat exchange means of the circuit is vented to the suction side of the compressor means so as to afford proper refrigerant charge control within the circuit. Control means are further disclosed which sense the load imposed upon the compressor means and prevent overloading thereof during operation in a water heating mode.

Apparatus for extracting potable water

Abstract: Apparatus and method for extracting potable water are disclosed in preferred form as extracting drinking water from moisture-laden air at atmospheric temperature through the use of a heat exchanger at or near subsurface temperature which is in air communication with the atmosphere for allowing atmospheric moisture-laden air to enter, pass through, cool, arrive at its dew point, allow the moisture in the air to precipitate out, and allow the air to pass outward to the atmosphere again. Suitable apparatus may be provided to restrict air flow and allow sufficient residence time of the air in the heat exchanger to allow sufficient precipitation. Further, filtration may be provided on the air input and a means for creating a movement pressure, in the preferred form of a turbine, may be provided on the output. The water from the system of the present invention may then be collected and provided for human consumption in conventional manner.

A Parametric Analysis of the Performance of Internally Finned Tubes for Heat Exchanger Application

Abstract: This paper presents a parametric analysis of the performance of internally finned tubes in turbulent forced convection for application to heat exchangers. The analysis compares the performance of an internally finned tube exchanger with that of an exchanger having internally smooth tubes. The calculations are performed for three important design cases.

Method and apparatus for treatment of biological substances, particularly for cultivation of biological cells and tissues, or of microorganisms

Abstract: To establish predetermined humidity levels within a sterile treatment chamber, and maintain sterility, water, preferably deionized, is conducted to an evaporator outside of a container defining the treatment chamber, to be there heated to superheated steam, for example in the order of 300° C., and conducted to a bypass duct (1) in atmospheric communication with the treatment chamber (10), for mixing with the atmosphere within the treatment chamber. Preferably, the treatment chamber is surrounded by heat exchanger elements, such as electrical heating wires and/or cooling coils, the heaters being controlled to rapidly heat the treatment chamber to a temperature in the order of 180° C. during pauses of treatment for sterilizing the interior of the container, and/or maintaining temperature levels at a desired treatment level in operation. Additional gases to establish controlled atmospheres can be admitted to the interior of the treatment chamber, preferably after having passed through a heat exchanger for establishment of a desired temperature level.

Multistage clean-up of product gas from underground coal gasification

Abstract: The present invention provides a multistage process for the removal of tar, water and particulate contaminants from a hot product gas resulting from the in-situ gasification of an underground coal deposit, which comprises passing the hot product gas through a first heat exchange zone in indirect heat exchange relationship with a gasification gas to thereby sufficiently reduce the temperature of the product gas so as to separate the tar present in the product gas and provide a substantially tar-free product gas. Thereafter, the tar-free product gas is withdrawn from the first heat exchange zone and passed through at least one subsequent heat exchange zone in indirect or direct heat exchange relationship with a heat exchange material which has a lower temperature than the product gas. A major portion of the water originally present in the hot product gas is removed in the subsequent heat exchange zone. The gasification gas, used to cool the hot product stream by means of indirect heat exchange, is passed to an underground coal deposit and utilized therein to gasify the same. A fluidized bed heat exchanger may be used in the first heat exchange zone in order to substantially completely remove tar and particulate contaminants.

Underground air tempering system

Abstract: An underground air tempering system for warming the supply air to a building in the winter and cooling the supply air in the summer in which a heat exchanger containing heat transfer material is disposed beneath the surface of the ground and the air supply to the building is drawn through the heat exchanger to be tempered by the substantially constant ground temperature. Two or more heat exchangers may be interconnected on the air supply and air distribution ends for supplying a sufficient volume of tempered air to large buildings. The underground air tempering system cleanses the air by removing dust and other particles therefrom, and moderates the humidity of the air by warming and humidifying cold dry winter air and by cooling and dehumidifying hot moist summer air. To maintain free flowing air passages, and to eliminate fungal and bacterial growth in the heat exchanger, a disinfectant and wash solution system is disposed above the heat transfer material for periodic cleansing of the material.

Solar energy heating system

Abstract: The invention basically includes a movable base which contains a plurality of hyperbolic mirror reflectors having their axis directed upwardly towards an absorber plate and which is directed upon an energy converting unit The solar energy is absorbed by the unit and is used to heat a gas such as air which is circulated through the unit, with the heat being subsequently stored in a heat absorbing particulate material such as lava rock or the like Additionally, the movable platform is controlled by a gravity drive (for very low power consumption during operation) and which is in turn controlled by a photoelectric solar detector mechanism The detector mechanism is so designed that it receives the early rays of light of the sun and signals the control system to commence tracking the sun This operation continues until the sun sets, at which time a signal is sent to the control system to return the platform to its original position in the east whereby it is available for commencing the tracking of the sun the following day The heat stored within the rock is transferred to a water system which includes pipes so that the heated water may be used to furnish the necessary heat to the particular structure being serviced

Precooler for gas turbines

Abstract: A system for cooling, cleaning and humidifying air entering an air breathing gas turbine. The air is first cooled on the dry side of an indirect evaporative heat exchanger and then moistened and cleaned by a fine water spray of distilled water obtained from a boiler heated with excess heat from the gas turbine and condensed by the moist cool air leaving the wet side of the heat exchanger.

Energy conservation in shower bathing

Abstract: Disclosed is a method and apparatus for decreasing the energy consumed by shower baths. The apparatus comprises a heat exchanger used to preheat incoming cold water with hot drain water and a local hot water heater used to elevate the temperature of the hot water feed to levels above about 170° F. The local heater and heat exchanger cooperate to result in energy savings of approximately 50% or more.

Water-lithium bromide double-effect absorption cooling analysis

Abstract: A numerical model was developed for the transient simulation of the double-effect, water-lithium bromide absorption cooling machine, and the use of the model to determine the effect of the various design and input variables on the absorption unit performance The performance parameters considered were coefficient of performance and cooling capacity The sensitivity analysis was performed by selecting a nominal condition and determining performance sensitivity for each variable with others held constant The variables considered in the study include source hot water, cooling water, and chilled water temperatures; source hot water, cooling water, and chilled water flow rates; solution circulation rate; heat exchanger areas; pressure drop between evaporator and absorber; solution pump characteristics; and refrigerant flow control methods The performance sensitivity study indicated in particular that the distribution of heat exchanger area among the various (seven) heat exchange components is a very-important design consideration Moreover, it indicated that the method of flow control of the first effect refrigerant vapor through the second effect is a critical design feature when absorption units operate over a significant range of cooling capacity The model was used to predict the performance of the Trane absorption unit with fairly good accuracy

A heat exchanger in plants for ventilating rooms or buildings.

Abstract: A heat exchanger in plants for ventilating dwelling rooms, for example. The heat exchanger (10) is of the recuperative type with two duct systems (11, 12) separated by a plurality of heat-transferring partition walls (16). Supply air and exhaust air are controlled by a valve means (33) to alternate, so that the two air streams are periodically shunted between the two duct systems depending, inter alia, on the outside air temperature and the inside air temperature and humidity. By means of shunting there is avoided, inter alia, condensation and possible frost formation in the heat exchanger simultaneously as the efficiency of the heat exchanger is improved.

Finned tube heat exchangers: State of the art for the air side

Abstract: The findings of various investigators during the past ten years has greatly enhanced our ability to analyze, model, design, and optimize the finned tube heat exchangers so widely used in the HVAC business. The effect of rows, fin pitch, and other geometric parameters are now well understood and generalized heat transfer correlations are available. The relation between heat and mass transfer has been much better defined and good correlations have been developed. Some advances have also been made in modeling techniques especially where partially dry cooling and dehumidifying coils are involved. All of these factors are reviewed to concisely summarize what is now available to the heat exchanger analyst.

Sun tracking solar energy collector system

Abstract: A sun tracking solar energy collector system comprising a plurality of light focusing elements disposed side by side in the form of a surface array, providing a linear array of foci; and a metallic heat exchanger tube having externally a high absorbtivity, low reflectivity coating containing a working fluid such as water, air, hydrogen or helium, to which a substantial portion of the energy in the focused light is imparted. The system includes an insulator tube external to the heat exchanger and providing small apertures covered by glass to allow the light focused by each focusing element to enter the interior of the insulator tube, where the light may impinge directly on the heat exchanger tube or on solar cells attached to the heat exchanger and facing the apertures, for conversion of a portion of the focused light energy directly into electricity, while the greater portion of the energy focused through the apertures ends up as heat through the heat exchanger tube into the working fluid, capable of raising its temperature to a desirable temperature. A highly reflective internal surface of the insulator tube serves to reflect toward the heat exchanger radiation reaching it from the solar cells and the heat exchanger, so that with the reflective internal surface being much larger than the surface covered by the apertures a very small percentage of the radiated energy is allowed to escape to space through the apertures. A vacuum maintained between the heat exchanger and the external insulator tube serves to minimize conductive losses.