Abstract: A photovoltaic device includes a substrate structure and at least one Se-containing layer, such as a CdSeTe layer. A process for manufacturing the photovoltaic device includes forming the CdSeTe layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process can also include controlling a thickness range of the Se-containing layer.

Abstract: A photovoltaic device includes a substrate structure and at least one Se-containing layer, such as a CdSeTe layer. A process for manufacturing the photovoltaic device includes forming the CdSeTe layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process can also include controlling a thickness range of the Se-containing layer.

Abstract: A doped photovoltaic device is presented. The photovoltaic device includes a semiconductor absorber layer or stack disposed between a front contact and a back contact. The absorber layer comprises cadmium, selenium, and tellurium doped with Ag, and optionally with Cu. The Ag dopant may be added to the absorber in amounts ranging from 5×1015/cm3 to 2.5×1017/cm3 via any of several methods of application before, during, or after deposition of the absorber layer. The photovoltaic device has improved Fill Factor and PMAX at higher Pr(=Isc*Voc product) values, e.g. about 160 W, which results in improved conversion efficiency compared to a device not doped with Ag. Improved PT may result from increased Isc, increased Voc, or both.

Abstract: A suction duct is disposed within a shell and tube heat exchanger. The suction duct is located relatively high and above the tube bundle so as to not entrain liquid or droplets that may be splashing and spraying upward. The suction duct is configured with an area schedule in fluid communication with a flow path inside the suction duct. The flow path is in fluid communication with an outlet of the shell. This is advantageous relative to traditional top of the shell outlets which generally have higher vertical footprints. The area schedule of the suction duct can facilitate and/or maintain relatively smooth vapor flow within the shell. The area schedule can achieve vapor flows that have some uniformity along the length of the shell, which can manage and/or avoid localized vapor flow and/or local currents, such as where high velocity may be present and where entrainment can result.

Abstract: Generally, management of refrigerant in an evaporator of an HVAC chiller is described. Methods, systems, and apparatuses to manage refrigerant in an evaporator can include one or combination of the following approaches: (1) by use of a refrigerant displacement array to physically prevent refrigerant from residing where the array is positioned (2) by control of the interstitial velocity of refrigerant flow within the volume of the shell of an evaporator; (3) by a phase biased distribution of the refrigerant mixture, so that a gaseous portion is uniformly distributed into the evaporator shell, while liquid refrigerant and oil is distributed into the evaporator shell at a designated area; and (4) by preventing or reducing the occurrence of foaming inside the evaporator through anti-foaming surfaces, such as by the use of refrigerant phobic and lubricant phobic material(s). Refrigerant management can in turn improve the thermal performance and overall efficiency of the evaporator.

Abstract: A heat exchanger, for example a shell and tube flooded evaporator, has a refrigerant distributor that is positioned at an angle between the bottom of the shell and the sides of the shell, and includes an inlet that is welded to an inlet piping, where the inlet and inlet piping are in fluid communication with the refrigerant distributor, and are in a generally corresponding position orientation. Tubes of a tube bundles may extend proximate the bottom of the shell.

Abstract: Generally, management of refrigerant in an evaporator of an HVAC chiller is described. Methods, systems, and apparatuses to manage refrigerant in an evaporator can include one or combination of the following approaches: (1) by use a refrigerant displacement array to physically prevent refrigerant from residing where the array is positioned; (2) by control of the interstitial velocity of refrigerant flow within the volume of the shell of an evaporator; (3) by a phase biased distribution of the refrigerant mixture, so that a gaseous portion is uniformly distributed into the evaporator shell, while liquid refrigerant and oil is distributed into the evaporator shell at a designated area; and (4) by preventing or reducing the occurrence of foaming inside the evaporator through anti-foaming surfaces, such as by the use of refrigerant phobic and lubricant phobic material(s). Refrigerant management can in turn improve the thermal performance and overall efficiency of the evaporator.

Abstract: A suction duct is disposed within a shell and tube heat exchanger. The suction duct is located relatively high and above the tube bundle so as to not entrain liquid or droplets that may be splashing and spraying upward. The suction duct is configured with an area schedule in fluid communication with a flow path inside the suction duct. The flow path is in fluid communication with an outlet of the shell. This is advantageous relative to traditional top of the shell outlets which generally have higher vertical footprints. The area schedule of the suction duct can facilitate and/or maintain relatively smooth vapor flow within the shell. The area schedule can achieve vapor flows that have some uniformity along the length of the shell, which can manage and/or avoid localized vapor flow and/or local currents, such as where high velocity may be present and where entrainment can result.

Abstract: Embodiments of a water head for an evaporator in a HVAC system are provided. The water head may have a fluid entrance and a fluid exit in a side-by-side arrangement on one end of the water head, and a distribution chamber and a collection chamber in a top-down arrangement on opposite side of the water head. The distribution chamber and the collection chamber are configured to be in fluid communication with inlets and outlets of a heat exchanging tube bundle respectively. The distribution chamber and the collection chamber can be configured to have continuously smooth surface contours to help reduce pressure drop and fluid separation, and promote advantageous distribution of the process fluid among heat exchanging tubes when a process fluid flows between the fluid entrance or the fluid exit, and the distribution chamber or the collection chamber respectively.

Abstract: A suction duct is disposed within a shell and tube heat exchanger. The suction duct is located relatively high and above the tube bundle so as to not entrain liquid or droplets that may be splashing and spraying upward. The suction duct is configured with an area schedule in fluid communication with a flow path inside the suction duct. The flow path is in fluid communication with an outlet of the shell. This is advantageous relative to traditional top of the shell outlets which generally have higher vertical footprints. The area schedule of the suction duct can facilitate and/or maintain relatively smooth vapor flow within the shell. The area schedule can achieve vapor flows that have some uniformity along the length of the shell, which can manage and/or avoid localized vapor flow and/or local currents, such as where high velocity may be present and where entrainment can result.

Abstract: A photovoltaic device includes a substrate structure and at least one Se-containing layer, such as a CdSeTe layer. A process for manufacturing the photovoltaic device includes forming the CdSeTe layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process can also include controlling a thickness range of the Se-containing layer.

Abstract: A photovoltaic device includes a substrate structure and at least one Se-containing layer, such as a CdSeTe layer. A process for manufacturing the photovoltaic device includes forming the CdSeTe layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process can also include controlling a thickness range of the Se-containing layer.

Abstract: A doped photovoltaic device is presented. The photovoltaic device includes a semiconductor absorber layer or stack disposed between a front contact and a back contact. The absorber layer comprises cadmium, selenium, and tellurium doped with Ag, and optionally with Cu. The Ag dopant may be added to the absorber in amounts ranging from 5×1015/cm3 to 2.5×1017/cm3 via any of several methods of application before, during, or after deposition of the absorber layer. The photovoltaic device has improved Fill Factor and PMAX at higher Pr (=Isc*Voc product) values, e.g. about 160 W, which results in improved conversion efficiency compared to a device not doped with Ag. Improved PT may result from increased Isc, increased Voc, or both.

Abstract: A heat exchange tube combines an external surface feature, for example having crushed fins and cavities, which can have very high boiling enhancement characteristics, with an internal surface feature, for example having high performing intersecting helices, e.g. “cross hatched” with an intersecting helix angle. The new tube can provide a high performing tube in a shell and tube evaporator that can be relatively smaller, more efficient, and that can use relatively lower refrigerant charge.

Abstract: A photovoltaic device includes a substrate structure and at least one Se-containing layer, such as a CdSeTe layer. A process for manufacturing the photovoltaic device includes forming the CdSeTe layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process can also include controlling a thickness range of the Se-containing layer.

Abstract: Methods and systems to manage refrigerant levels in a chiller system are provided. An evaporator of the chiller system may be configured to have a spill over port allowing oil containing refrigerant to spill over through the spill over port. The spill over port may be positioned at a place that corresponds to a desired refrigerant level in the evaporator. The spill over refrigerant may be directed into a heat exchanger that is configured to substantially vaporize refrigerant of the spill over refrigerant to a slightly superheat temperature. A method of maintaining a proper refrigerant level in the evaporator may include regulating a refrigerant flow to the evaporator so that the vaporized refrigerant of the spill over refrigerant is maintained at the slightly superheat temperature.

Abstract: A heat exchanger, for example a shell and tube flooded evaporator, has a refrigerant distributor that is positioned at an angle between the bottom of the shell and the sides of the shell, and includes an inlet that is welded to an inlet piping, where the inlet and inlet piping are in fluid communication with the refrigerant distributor, and are in a generally corresponding position orientation. Tubes of a tube bundles may extend proximate the bottom of the shell.

Abstract: A heat exchanger, for example a shell and tube flooded evaporator, has a refrigerant distributor that is positioned at an angle between the bottom of the shell and the sides of the shell, and includes an inlet that is welded to an inlet piping, where the inlet and inlet piping are in fluid communication with the refrigerant distributor, and are in a generally corresponding position orientation. Tubes of a tube bundles may extend proximate the bottom of the shell.

Abstract: A suction duct is disposed within a shell and tube heat exchanger. The suction duct is located relatively high and above the tube bundle so as to not entrain liquid or droplets that may be splashing and spraying upward. The suction duct is configured with an area schedule in fluid communication with a flow path inside the suction duct. The flow path is in fluid communication with an outlet of the shell. This is advantageous relative to traditional top of the shell outlets which generally have higher vertical footprints. The area schedule of the suction duct can facilitate and/or maintain relatively smooth vapor flow within the shell. The area schedule can achieve vapor flows that have some uniformity along the length of the shell, which can manage and/or avoid localized vapor flow and/or local currents, such as where high velocity may be present and where entrainment can result.

Abstract: A spill over tank for an evaporator of a HVAC system may be configured to receive a refrigerant spilled over from the evaporator. The spill over tank may be configured to have an outlet that directs the refrigerant in the spill over tank out of the spill over tank. The refrigerant may flow through the outlet back to a compressor of the HVAC system. The spill over tank may be equipped with a refrigerant level sensor configured to measure a refrigerant level in the spill over tank. The measured refrigerant level in the spill over tank may be used to control and/or maintain a refrigerant level in the evaporator, and/or may be used to control a return refrigerant flow into the compressor of the HVAC system so as to manage an oil return to the compressor.