Abstract: A bypass system is incorporated into a roof curb to permit selective partial or complete deactivation of at least one section of a heat pipe of an air conditioning system thereby 1) to permit optimization of the sensible heat ratio of the air conditioning system for prevailing environmental conditions and, 2) to prevent moisture from condensing onto the evaporator or cooling section of the heat pipe and subsequently dripping into the return ducts of the air conditioning system. The bypass system is characterized by a bypass duct located adjacent one of the sections of the heat pipe and a bypass device which selectively channels at least some of the air which would otherwise flow through the controlled section of the heat pipe through the bypass duct instead. In its simplest form, the bypass device may comprise a single damper or the like positioned within the bypass duct.

Abstract: The heat exchange efficiency of a finned tube heat exchanger is increased by providing secondary heat exchange surfaces which are dimensioned and configured to maximize heat exchange with the surrounding fluid. These secondary heat exchange surfaces, formed from materials which would normally be wasted when blanks are removed from the fins to form apertures for receiving the tubes, are formed by bending the preserved materials into star-shaped structures which increase the surface area in contact with the surrounding fluid. The secondary heat exchange surfaces increase the surface area of the fin which is available for heat exchange, and provide this increased surface area at a location maximizing heat transfer capability to the surrounding fluid and to the tubes. The heat exchanger can be constructed in a simple and inexpensive process while preventing fin presses or related machinery from being jammed by removed materials.

Abstract: A metalworking tool is capable of making internally grooved and externally finned heat exchanger coils from ordinary tubes in a single operation in which the tubes are expanded into bonding mechanical contact with external fins at the same time that grooves are formed in the inner surfaces of the tubes. The process is performed by a tool head having both expanding and groove forming tools mounted thereon. The expanding tool preferably comprises a hardened expansion ball which mechanically expands the tube with or without hydraulic or pneumatic assist. The groove forming tool may comprise a cutting point which scribes the tube, a roller which forges a groove, or any other suitable scribing or forging device. The groove forming tool may rotate or oscillate to produce nonlinear grooves and may form grooves during the in-going and/or out-going strokes of the tool.

Abstract: A lightweight speaker is constructed without permanent magnets by providing two coils, one of which is mounted on a movable membrane and the other of which is mounted on a fixed frame. The coils are mounted in close proximity to one another and excited by a common source signal from a common amplifier or the like in such a fashion that the electromagnetic fields created by the coils upon excitation interact to cause the coils to alternately attract and repel one another. One of the coils is fed with an excitation signal directly from the source. The other coil receives the source signal only indirectly, preferably via a bridge rectifier. The coils may take the form of conventional wound wires or, in a particularly sophisticated yet inexpensive embodiment, may be formed on a printed circuit board in the form of flat spirals. The resulting speaker is very lightweight and thus is well suited for use in automobiles, airplanes, and other applications in which weight minimization is important.

Abstract: An air conditioning system uses heat-pipes in combination with a cooling coil to increase either the dehumidification capacity or the efficiency and capacity of an air-conditioning system. In the dehumidification mode, the secondary cooling coil is inactive, and the heat pipes operate as a heat-exchanger between the warm return air and the cold supply air of the air conditioning system to precool the return air and reheat the supply air, increasing the latent capacity of the main cooling coil. In the efficiency and capacity boosting mode, the secondary cooling coil is activated by introducing a portion of the cooling fluid from the air-conditioning system. This results in a neutralization of the effect of the heat pipes as well as an increase in effective heat-exchange area between the cooling fluid and the air, therefore produces an increase in the capacity of the system.

Abstract: A single assembly heat transfer device installed in an environmental control apparatus having a primary evaporator, a two-section heat pipe having an evaporator section and a condenser section, and an end plate. The primary evaporator, the evaporator section and the condenser section are mounted on the end plate, thereby forming a single assembly.

Abstract: An impeller displaces fluids without turbulence, thereby reducing noise and increasing efficiency. The impeller employs annular disks stacked on a shaft which may be rotatably mounted in a specially shaped housing. The disks cooperate with a complementary surface formed, e.g., by the interior of the impeller housing or by another impeller, so as to use a combination of surface friction, centrifugal forces, and a venturi effect to propel fluids tangentially without turbulence. The impeller is well suited for use with a heat exchange device because the flat disks present a large surface area providing good heat exchange with fluids flowing past the disks. A heat pipe or other suitable heat transfer mechanism may be provided in the shaft of the impeller to form a heat transfer system integral with the impeller for heating or cooling purposes.

Abstract: A damper includes an elastic bladder which is attached to and surrounds a support element mountable in a ventilation duct. The bladder inflates when supplied with fluid to restrict the available air space within the duct, thus restricting airflow through the duct. The amount of restriction can be regulated by monitoring the degree of inflation of the bladder and by controlling the degree of inflation to provide the desired airflow restriction rate. The bladder may be inflated by supplying pressurized air to the interior of the bladder through the support element or by vaporizing a refrigerant in communication with the bladder. The damper may comprise a single bladder extending longitudinally through the duct or a plurality of bladders extending transversely across the duct.

Abstract: A dryer is designed as a closed system in which heated air used to dry the materials is continuously recycled within the drying compartment of the dryer without being discharged to the atmosphere, thus increasing the efficiency of the system while preventing the discharge of contaminated vapors to the atmosphere and also conserving energy which would otherwise be required to heat or air-condition the air drawn into the dryer from the building in which the dryer is located. A regenerative heat exchanger and an atmospheric cooler/condenser are provided in the dryer and condense and remove moisture from the saturated air and transfer the heat of condensation back into the air before the air is reheated and recycled back to the materials to be dried. The drying compartment may comprise an enclosed tunnel through which a rack of superposed trays are conveyed or may comprise some other conveying mechanism.

Abstract: An air conditioning system uses heat-pipes in combination with a cooling coil to increase either the dehumidification capacity or the efficiency and capacity of an air-conditioning system. In the dehumidification mode, the secondary cooling coil is inactive, and the heat pipes operate as a heat exchanger between the warm return air and the cold supply air of the air conditioning system to precool the return air and reheat the supply air, increasing the latent capacity of the main cooling coil. In the efficiency and capacity boosting mode, the secondary cooling coil is activated by introducing a portion of the cooling fluid from the air-conditioning system. This results in a neutralization of the effect of the heat pipes as well as an increase in effective heat-exchange area between the cooling fluid and the air, therefore produces an increase in the capacity of the system.

Abstract: A passive defrost system uses a heat-exchanger/storage defrost module containing a thermal storage material such as a phase change material to capture and store low grade, waste heat contained in the liquid refrigerant line of a refrigeration system. The waste heat is stored during normal operation. Upon shut down of the refrigeration system, the stored heat in the defrost module is released by an automatic device for defrosting the evaporator. The preferred embodiment of this passive defrost system includes the defrost module and some device to transfer heat from the defrost module to the evaporator, preferably in the configuration of a gravity heat pipe. Since waste heat is taken out of the liquid refrigerant line, the efficiency of the refrigeration system is improved, and no additional energy is needed for the defrost operation.

Abstract: A regenerative fresh-air air conditioning system moves ingoing and outgoing air through a building structure and includes an ingoing air portion wherein the ingoing air is filtered and then pre-cooled by a pre-cooling heat pipe. The ingoing air is then moved by a blower to an evaporator where the air is further cooled and a resulting condensate forms. The cooled air is then supplied to the building by a supply register. Outgoing air passes across a wet heat pipe which is wetted by the condensate from the evaporator and may also be wetted by condensate from the pre-cooling heat pipe. The outgoing air is then sub-cooled and mixed with fresh air by a fan which moves the mixed fresh and outgoing air across a condenser and exhausts the mixed air from the building structure.

Abstract: An evaporative cooling system is disclosed which uses a heat pipe device comprising first and second heat exchangers to transfer heat from the space being cooled to an evaporative cooler. Evaporative cooling is produced by passing atmospheric air over wet pads and the first heat exchanger. Evaporation of water removes heat from the atmospheric air and from the first heat exchanger containing refrigerant vapor, causing condensation of a portion of the vapor. The condensate moves to the second heat exchanger which contains liquid refrigerant. Room air is passed through the second heat exchanger and gives up heat to vaporize the liquid refrigerant. Vaporized refrigerant moves to the first heat exchanger where it is condensed as previously described. The cooled atmospheric air is then used to cool the condenser of a vapor compression machine, the evaporator of which is located in the flow path of the room air downstream of the heat pipe, further cooling the room air to desired conditions.

Abstract: The system in the present invention includes HVAC unit, such as an air-conditioner, having an evaporator coil, and a heat exchanger for drawing heat from air entering the inlet side of the air-conditioner evaporator and supplying heat to air at the outlet side of the air-conditioner evaporator. The heat exchanger is a phase change heat pipe-type heat exchanger, having a evaporator before the air-conditioning evaporator and a condenser after the air-conditioner evaporator.

Abstract: A flash compression process for the manufacture of photovoltaic cells wherein a powder of photovoltaic material is compressed under high pressure between upper and lower compression members and is simultaneously melted in place by means of an electric discharge supplied through the compression members. The photovoltaic material is subjected to a controlled solidification process by which impurities are confined to one side of the photovoltaic cell. The photovoltaic cell may be formed directly on a substrate and may be surface doped during the formation process.

Abstract: The present invention is a device for a solar heating system having a solar collector, a storage tank connected to the solar collector, a pump for circulating liquid from the tank to the solar collector, a supply of liquid at a temperature above freezing and a connection from the supply of liquid to the solar collector for replacing any liquid lost from said solar collector. The device comprises a sensor for sensing the temperature of liquid in the solar collector, and a valve for bleeding liquid from the solar collector when the sensed temperature falls below a predetermined minimum whereby cool liquid in the solar collector is automatically replaced by liquid at a temperature above freezing.

Abstract: The invention comprises a photovoltaic panel for converting solar energy into electric energy, a load and a capacitor connected to the photovoltaic panel for receiving current produced by the panel and storing the current to produce an output voltage which increases with the amount of stored current. A relay connects the photovoltaic panel and capacitor to the inductive load when the output voltage of the capacitor has reached a predetermined level which corresponds to an optimum operating voltage range of the photovoltaic panel.