Abstract: A photocatalytic air purifier is disclosed. The photocatalytic purifier includes filter structures coated with a catalytic material such as titanium dioxide. One or more UV lamps are interposed between the filter structures. The catalytic layer reacts with airborne VOCs and bioaerosols when activated by the UV lamps to thereby oxidize the VOCs and destroy the bioaerosols. The photocatalytic air purifier does not need to be replaced or regenerated after a period of continuous usage. The photocatalytic purifier of the present invention substantially eliminates odors, VOCs, and bioaerosols from air directed through the fan coil. The photocatalytic air purifier includes a control system that optimizes operating costs. Because of these features, service, maintenance, and filter replacement are reduced to a minimum. At the same time, the well being of persons living in the space conditioned by the photocatalytic air purifier is improved.

Abstract: A photocatalytic air purifier is disclosed. The photocatalytic purifier includes filter structures coated with a catalytic material such as titanium dioxide. One or more UV lamps are interposed between the filter structures. The catalytic layer reacts with airborne VOCs and bioaerosols when activated by the UV lamps to thereby oxidize the VOCs and destroy the bioaerosols. The photocatalytic air purifier does not need to be replaced or regenerated after a period of continuous usage. The photocatalytic purifier of the present invention substantially eliminates odors, VOCs, and bioaerosols from air directed through the fan coil. The photocatalytic air purifier includes a control system that optimizes operating costs. Because of these features, service, maintenance, and filter replacement are reduced to a minimum. At the same time, the well being of persons living in the space conditioned by the photocatalytic air purifier is improved.

Abstract: A condenser coil for a refrigerated beverage and food service merchandiser includes a plurality of parallel fins or V-shaped fins between adjacent tubes. In order to reduce the likelihood of fouling by the bridging of fibers therebetween, the spacing of the fins is maintained at a distance of 0.4 to 0.8 inches apart. In one embodiment, the coil includes a plurality of flat multichannel tubes, with no fins therebetween, and the spacing between the multichannel tubes is maintained in the range of 0.4 to 0.8 inches. In one embodiment, the coil includes at least one serpentine shaped, multichannel tubes, with no fins therebetween, and the spacing between flat, parallel segments of the multichannel tubes is maintained in the range of 0.4 to 0.8 inches.

Abstract: A condenser coil for a refrigerated beverage and food service merchandiser includes a plurality of parallel fins between adjacent tubes. In order to reduce the likelihood of fouling by the bridging of fibers therebetween, the spacing of the fins is maintained at a distance of 0.4 to 0.8 inches apart. In one embodiment, the tubes comprise microchannel tubes, with no fins therebetween, and the spacing between the microchannel tubes is maintained in the range of 0.75 inches to optimize the heat transfer performance while minimizing the occurrence of fouling. A supporting structure is provided between microchannel tubes when no fins are included. Also, plural rows of microchannel tubes are provided with separate inlet headings and with the rows being staggered in transverse relationship to enhance the heat transfer characteristic while minimizing the likelihood of fouling.

Abstract: A photocatalytic air purifier is disclosed. The photocatalytic purifier includes filter structures coated with a catalytic material such as titanium dioxide. One or more UV lamps are interposed between the filter structures. The catalytic layer reacts with airborne VOCs and bioaerosols when activated by the UV lamps to thereby oxidize the VOCs and destroy the bioaerosols. The photocatalytic air purifier does not need to be replaced or regenerated after a period of continuous usage. The photocatalytic purifier of the present invention substantially eliminates odors, VOCs, and bioaerosols from air directed through the fan coil. The photocatalytic air purifier includes a control system that optimizes operating costs. Because of these features, service, maintenance, and filter replacement are reduced to a minimum. At the same time, the well being of persons living in the space conditioned by the photocatalytic air purifier is improved.

Abstract: A photocatalytic air purifier is disclosed. The photocatalytic purifier includes filter structures coated with a catalytic material such as titanium dioxide. One or more UV lamps are interposed between the filter structures. The catalytic layer reacts with airborne VOCs and bioaerosols when activated by the UV lamps to thereby oxidize the VOCs and destroy the bioaerosols. The photocatalytic air purifier does not need to be replaced or regenerated after a period of continuous usage. The photocatalytic purifier of the present invention substantially eliminates odors, VOCs, and bioaerosols from air directed through the fan coil. The photocatalytic air purifier includes a control system that optimizes operating costs. Because of these features, service, maintenance, and filter replacement are reduced to a minimum. At the same time, the well being of persons living in the space conditioned by the photocatalytic air purifier is improved.

Abstract: In an air conditioning system which includes a catalytic air purifier, a control system is provided for sensing the level of predetermined conditions in a space and for responsively modulating the air purification process in a manner which optimizes the process in terms of its effectiveness and its economical use. The conditions that are sensed include the levels of VOC's, CO2, and biological contaminants, as well as degree of occupancy, relative humidity and air flow. The air purification process is modulated by varying the power to a UV lamp, turning one or more UV lamps on or off, varying the effectiveness of the catalyst, varying the volume or speed of the air flowstream and/or varying the relative humidity in the space.

Abstract: In an air conditioning system which includes a catalytic air purifier, a control system is provided for sensing the level of predetermined conditions in a space and for responsively modulating the air purification process in a manner which optimizes the process in terms of its effectiveness and its economical use. The conditions that are sensed include the levels of VOC's, CO2, and biological contaminants, as well as degree of occupancy, relative humidity and air flow. The air purification process is modulated by varying the power to a UV lamp, turning one or more UV lamps on or off, varying the effectiveness of the catalyst, varying the volume or speed of the air flowstream and/or varying the relative humidity in the space.

Abstract: A photocatalytic air purifier is disclosed. The photocatalytic purifier includes filter structures coated with a catalytic material such as titanium dioxide. One or more UV lamps are interposed between the filter structures. The catalytic layer reacts with airborne VOCs and bioaerosols when activated by the UV lamps to thereby oxidize the VOCs and destroy the bioaerosols. The photocatalytic air purifier does not need to be replaced or regenerated after a period of continuous usage. The photocatalytic purifier of the present invention substantially eliminates odors, VOCs, and bioaerosols from air directed through the fan coil. The photocatalytic air purifier includes a control system that optimizes operating costs. Because of these features, service, maintenance, and filter replacement are reduced to a minimum. At the same time, the well being of persons living in the space conditioned by the photocatalytic air purifier is improved.

Abstract: A heat transfer tube (10) for use in an application, such as a shell and tube type air conditioning system condenser, in which a fluid flowing through the heat exchanger external to the tubes condenses by transfer of heat to a cooling fluid flowing through the tubes. The tube has at least one fin convolution (20) extending helically around its external surface (13). A pattern of notches (30) extends at an oblique angle (&agr;) across the fin convolutions at intervals about the circumference of the tube. There is a spike (22) between each pair of adjacent notches. The fin convolution, notches and spikes are formed in the tube by rolling the wall of the tube between a mandrel and, first, a gang of finning disks (63) and, second, a notching wheel (66). Because, during the manufacture of the tube, of the interaction of the rotating and advancing tube and the notching wheel, the angle (&bgr;) of inclination of the axis of the tip of the spike is oblique with respect to the notch angle.

Abstract: A vapor compression refrigeration system for cooling a liquid in which there is a spray dispenser for distributing liquid refrigerant over the tubes in a shell-and-tube type evaporator. The differential pressure in the refrigerant flow loop across the evaporator is the sole means of producing a flow through the spray dispenser. The evaporator is operated as a hybrid falling film heat exchanger, that is, in a semi-flooded condition. The lower portion of the evaporator shell is flooded with liquid refrigerant to wet the lower tubes in the tube bundle while the tubes in the upper portion are wetted only by refrigerant spray from the spray dispenser. The system is operated in a steady state condition whereby at least twenty-five percent (25%) of the tubes in the evaporator operate in a flooded heat transfer mode. The system allows a reduction in the amount of refrigerant charge in the system while at the same time avoiding the use of a recirculating system and pump.

Abstract: An improved heat transfer tube for use in air conditioning chillers of the shell and tube type. The tube (10) achieves objectives of improved manufacturability, heat transfer performance and fluid flow characteristics by having external helical fins (12) with specified ranges of fin heights and fin density for a specified range of tube outer diameters.

Abstract: A heat transfer tube having an internal surface that enhances the heat transfer performance of the tube. Helical ribs project from the internal surface of the tube. The ribs have a pattern of parallel notches intersecting and impressed into them at a small angle of inclination with respect to the longitudinal axis. The pattern of ribs and notches increase the total internal surface area of the tube and also promote conditions for the flow of refrigerant within the tube that increase heat transfer performance. The tube is suitable for use in both refrigerant evaporators and condensers.

Abstract: A tube for use in a heat exchanger where heat is transferred between a fluid flowing through the tube and a fluid flowing around the exterior of the tube and where the fluid external to the tube boils during the heat exchange process. The tube has one or more external fin convolutions extending from its external surface. At intervals along each side surface of the fin convolutions there are shoulder notches extending from the fin side surfaces. The groove space between adjacent fin convolutions has raised teeth located circumferentially at intervals. The fin convolutions do not extend perpendicularly from the tube surface but are inclined, with one convolution overlying an adjacent groove but not touching its adjacent neighbor fin convolution to form a re-entrant boiling cavity with an opening gap. In one embodiment, the opening gap extends completely around the circumference of the tube.

Abstract: A heat exchanger tube having an internal surface that enhances the heat transfer performance of the tube. The internal surface has ribs that run substantially parallel to the longitudinal axis of the tube. The ribs have a pattern of parallel notches intersecting and impressed into them at an angle oblique to the longitudinal axis. The pattern of ribs and notches increase the total internal surface area of the tube and also promote conditions for the flow of refrigerant within the tube that increase heat transfer performance.

Abstract: A heat exchanger tube (10) for use in an application, such as a shell and tube type air conditioning system condenser, in which a fluid flowing through the heat exchanger external to the tubes condenses by transfer of heat to a cooling fluid flowing through the tubes. The tube has at least one fin convolution (22) extending helically around its external surface (13). Multiple axial notches (23) are impressed into the fin at intervals along its extent. Because the notches are impressed and not cut into the fin, material displaced from a fin to form a notch forms lateral projections (24) from the the walls of the fin. The notched fins provide increased external heat transfer surface area on the tube, destabilize the film of condensate on the tube external surface, thus causing the film to be generally thinner, and promote condensate drainage from the fins and off the tube and thus increase the heat transfer performance of the tube.