Abstract: The invention relates to a turbine (1), in particular of an exhaust gas turbocharger, having a turbine rotor (4), which is rotatably mounted in a housing (2), with which at least one radial inlet channel (9) for a guide apparatus (7) forming a medium which drives the turbine rotor (4) is associated, wherein said guide apparatus (7) has multiple guide vane bearing rings (10), which radially enclose said turbine rotor (4) and have guide vanes (8) which lie in said inlet channel (9), and a guide vane cover ring (12), and wherein said inlet channel (9) is axially delimited by said guide vane bearing ring (10) and said guide vane cover ring (12) and said guide apparatus (7) is mounted in the housing (2) so it is axially and/or radially movable for material relaxation. Furthermore, the invention relates to an exhaust gas turbocharger, in particular for a motor vehicle.

Abstract: The invention relates to a method of positioning a pump in a well in order to create artificial lift. The method involves frictionally engaging a portion of the pump with a portion of the well, such that the pump is retained in a starting position. In order to progress the pump into the well, the pressure differential across the pump is increased, and then, when the pump is in a finishing position, the pressure differential across the pump is reduced such that the pump is once again retained in the finishing position by the frictional engagement between the pump and the well. A pump for use in the above method of deployment is also provided.

Abstract: A system includes a detector configured to detect a fog condition within an air flow directed toward a compressor. The system also includes a controller coupled to the detector, wherein the controller is configured to activate a first control measure in response to the fog condition.

Abstract: A turbocharger includes a semi-floating metal. The semi-floating metal is provided with a supply opening configured to supply oil to an inner bearing section. The turbocharger is provided with: an oil supply path which extends from inside of a bearing housing to the supply opening, and feeds the oil to be supplied to the inner bearing section; a removal section which changes a flowing direction of the oil supplied from an upstream side to separate minute foreign matter in the oil; and a conveyance path and a retaining region which collect the minute foreign matter separated by the removal section so as to prevent the minute foreign matter from mixing again with the oil flowing toward the supply opening.

Abstract: A bearing device includes: an outer ring housing in a cylindrical shape which is provided in a casing and has a discharge hole in an axially central portion of the outer ring housing and a notch groove passing through an axial end surface of the outer ring housing in the radial direction; and a rolling bearing mounted on each of both axial sides of the outer ring housing and rotatably supporting a rotational shaft positioned radially inside of the outer ring housing.

Abstract: An exhaust-gas turbocharger (1) having a turbine (2); having a compressor (3); and a bearing housing (4) which is arranged between the turbine (2) and the compressor (3) and a compressor-side flange (5) of which adjoins the compressor (3). A heat throttle (6, 6?) is arranged in the compressor-side flange (5) of the bearing housing (4).

Abstract: A turbocharger includes a turbine disc, a compressor wheel mechanically coupled to the turbine disc, and a single-walled air inlet. Made of ductile iron, the air inlet is configured to admit air to the compressor wheel and to provide clearance for rotation of the compressor wheel.

Abstract: An exemplary compressor is provided. The compressor includes a plurality of blades, a hub defining a front surface and a back surface, and a first flow restriction structure provided at the back surface of the hub. The plurality of blades are arranged in a predefined manner on the front surface for receiving input air flow at a first pressure and compressing the input air flow to provide an output air flow at a second pressure higher than the first pressure. The first flow restriction member is configured for preventing at least a portion of the output air flow at the second pressure from entering into the back surface of the hub to reduce an air pressure at the back surface of the hub.

Abstract: A support housing for a turbocharger is provided. The support housing may include an end wall with a first side and a second side, and a protrusion extending from the first side of the end wall in a first direction and configured to receive the turbocharger. The support housing may also include a plurality of side walls extending from the second side of the end wall in a second direction opposite the first direction. The plurality of side walls together with the end wall may form a generally hollow enclosure. The support housing may also include a first mounting flange disposed at distal edges of the plurality of side walls and configured to engage an engine, and a first center opening disposed in the end wall and passing from the first side to the second side.

Abstract: A support housing is disclosed for use with a turbocharger. The support housing may have an end wall, a semi-cylindrical protrusion extending from the end wall in a first direction, and a plurality of side walls extending from the end wall in a second direction. The plurality of side walls together with the end wall may form a generally hollow enclosure. The support housing may also include a mounting flange disposed at distal edges of the plurality of side walls, and a center opening disposed in the end wall. The support housing may further include a collection cavity formed at a gravitationally lowest corner of the end wall below the center opening and substantially isolated from the enclosure formed by the plurality of side walls and the end wall, and a gutter passage formed in the end wall and extending from the center opening to the collection cavity.

Abstract: A turbocharger includes a first bypass opening which introduces an exhaust gas from a first exhaust scroll to a downstream area downstream of the turbine impeller, and a second bypass opening which introduces the exhaust gas from a second exhaust scroll to the downstream area. The turbocharger further includes a waste gate valve opens and closes both the first bypass opening and the second bypass opening at the same time. Thus, the waste gate valve can function even though the switch valve is completely closed. Since the exhaust gas is introduced toward the downstream area via both the first bypass opening and the second bypass opening, a pressure loss is restricted and an exhaust pressure of the exhaust gas can be restricted. Further, a turbine efficiency can be improved.

Abstract: A turbocharger including a turbine wheel having a hub-to-tip ratio of no more than 60% and blades with a high turning angle, a turbine housing forming an inwardly spiraling primary-scroll passageway that significantly converges to produce highly accelerated airflow into the turbine at high circumferential angles, and a two-sided parallel compressor. The compressor and turbine each produce substantially no axial force, allowing the use of minimal axial thrust bearings.

Abstract: An exhaust-gas turbocharger (1) having a compressor (2) which has a compressor wheel (3) in a compressor housing (4); a turbine (5) which has a turbine wheel (6) in a turbine housing (7); a bearing housing (8) which receives a static bearing bush (9) for a rotor shaft (10) and which has, at the compressor side, a bearing housing cover (11), and a bearing bush rotation prevention means (12) which has at least one lug (13, 14, 15) supported in the bearing housing (8) and which engages into at least one of two grooves (16, 17) of the bearing bush (9). The grooves (16, 17) are arranged diametrically oppositely on an outer circumferential region (18) of the bearing bush (9).

Abstract: An actuator includes at least one stage of turbo compressor, with an outlet for conveying gas compressed in the at least one stage of turbo compressor to at least one cooler, and a shaft for rotating the at least one stage of turbo compressor, for increasing the pressure of the gas to be supplied to the actuator. The actuator also includes a turbine and a control valve by means of which the flow of compressed gas produced by the turbo compressor to the turbine is arranged to be adjusted. A method for controlling the actuator, as well as a control system for the actuator are also described.

Abstract: An exemplary center housing rotating assembly includes a turbine wheel (260); a compressor wheel (240); a center housing (210) that includes a through bore (215), extending from a compressor end to a turbine end along a bore axis, and a recess (217), adjacent the bore, in a plane orthogonal to the bore axis; a bearing assembly (230) positioned in the bore that includes a keyway (233); and an anti-rotation component (280) seated in the recess and at least partially in the keyway to restrict rotation of the bearing assembly in the bore. Various other exemplary devices, systems, methods, etc., are also disclosed.

Abstract: A generator arrangement comprises a turbocharger having a compressor configured to be placed in fluid flow communication with an engine inlet, and a first turbine having a first turbine wheel, a first inducer portion upstream, in use, of the first turbine wheel and configured to be placed in fluid flow communication with an engine outlet, and a first exducer portion downstream, in use, of the first turbine wheel; and an electrical generator having a second turbine having a second turbine wheel, a second inducer portion upstream, in use, of the second turbine wheel and configured to be placed in fluid flow communication with the engine outlet, and a second exducer portion downstream, in use, of the second turbine wheel. The first and second turbines are arranged in parallel to one another; and the first inducer portion and second inducer portion, and/or the first exducer portion and second exducer portion are contiguous.

Abstract: An exhaust-gas turbocharger (1), having a shaft (2) on which a compressor wheel (3) and a turbine wheel (4) are arranged, and a bearing housing (5) which has a turbine-side radial bearing bush (6) and which has an oil collecting chamber (7) arranged between the turbine-side radial bearing bush (6) and a turbine-side bearing housing end region (8). The shaft (2) has a shoulder (9) which extends outward in the radial direction (R) into the oil collecting chamber (7) and, together with a radial-bearing-side first delimiting wall (10) of the oil collecting chamber (7), delimits a gap (11).

Abstract: A pump assembly to move water past a reverse osmosis membrane, the pump assembly having a first pump and a second pump each including a bore having a longitudinal axis and surrounding a chamber. First and second partition members extend longitudinally of the chamber. The second partition is moveable relative to the first partition member, and divides the chamber into a first sub chamber and a second sub chamber. A shaft is attached to the second member to cause angular movement thereof about the axis to change the volumes of the sub chambers. End caps are fitted to ends of each chamber to contain pressure, and ducting is provided to provide for the flow of water. The shaft of the first pump is coupled to the shaft of the second pump so that the first pump second partition angularly oscillates in phase with the second pump second partition.

Abstract: At least one energy storage system is provided for receiving and releasing at least a part of the converted kinetic energy from a landing aircraft. The system has a high degree of multiple utilisation and enables, for example, manoeuvring of a landed aircraft on the taxiway independently of the engines, where the aircraft is substantially moved with the braking energy recovered during the landing process. As a result of the main engines no longer being required for manoeuvring, there is a considerable potential for saving energy and the use of motor-operated tow vehicles is eliminated. The apparatus also contributes in the sense of a “green” and economical technology to saving aircraft fuel and better fulfils future requirements of airports, particularly with a view to noise and pollutant reduction. In addition, the invention has as its subject matter a method for recovering braking energy of an aircraft.

Abstract: An exemplary shaft assembly of an air cycle machine includes a cylindrical body rotatably coupling a compressor rotor, a turbine rotor and a fan rotor. The cylindrical body has an axial length and a diameter. A ratio of the axial length to the diameter is from 34.82 to 35.18.

Abstract: A turbocharger includes a compressor, a turbine, a shaft coupling the compressor to the turbine, and a turbo casing configured to improve pressure recovery and reduce energy loss from exhaust flow. In one embodiment, the turbo casing may include a geometry configured to improve exhaust flow towards an exhaust outlet. The turbo casing may include a torus shaped chamber having a cross-sectional area that progressively increases in an annular direction of the flow towards the exhaust outlet.

Abstract: A turbocharger for an internal combustion engine, comprising a bearing housing, a rotating shaft coupled to the bearing housing, a compressor wheel mounted at one end of the rotating shaft, a compressor housing accommodating the compressor wheel and provided with an inlet and an outlet for an air stream, a turbine wheel mounted at the opposite end of the rotating shaft, and a turbine housing accommodating the turbine wheel and provided with an inlet and an outlet for an exhaust gas stream, wherein the bearing housing comprises a fastening flange suitable to be fixed to a component of the internal combustion engine, wherein the turbine housing is provided with a connecting pipe for fluidly connecting the turbine housing inlet with an exhaust manifold of the internal combustion engine, and wherein the connecting pipe includes means for compensating axial thermal deformations thereof.

Abstract: A scroll type device for operating on a fluid provided thereto that includes, as a unit, a housing with two interleaved scroll plates that are installed within such housing and that are operably movable relative to one another in an eccentric orbit, with such scroll plates including interleaved spiral projections, spiral projections include first and second portions, which portions will operate for expansion and the other of which portion will operate for compression as the unit operates in a given normal direction of movement.

Abstract: An oil well pumping apparatus for pumping oil from a well to a wellhead provides a tool body sized and shaped to be lowered into the production tubing string. A working fluid is provided that can be pumped into the production tubing, by a prime mover. A flow channel into the well bore enables the working fluid to be circulated from the prime mover via the production tubing to the tool body at a location in the well and then back to the wellhead area. A pumping mechanism is provided on the tool body, including upper and lower spur gear or gears connected with a common shaft. The upper spur gear is driven by the working fluid. The lower spur gear is rotated by the first spur gear. The tool body has flow conveying portions that mix the working fluid and the produced oil as the oil is pumped.

Abstract: A compressor apparatus for the turbocharger of a piston engine is provided. The compressor apparatus includes a compressor for compressing a flowing medium to produce a compressed medium and a return device by which at least a partial stream of the compressed medium is fed anew to the compressor.

Abstract: The turbocharger comprises a shaft 14, a housing 12, a turbine wheel 20 and a compressor wheel 22 mounted onto the shaft, and at least a rolling bearing 18 disposed between the shaft and the housing and comprising an inner ring 26, an outer ring 28 and at least one row of rolling elements 30 disposed into a rolling space 40 defined between the rings. A damping space 38 is defined between an outer surface 28a of the outer ring and a bore 16 of the housing inside which a lubricant is located.

Abstract: A variable geometry turbocharger is simplified yet able to reliably operate in a robust, cost effective manner. The adjusting ring assembly has a reduced number of parts in the vane adjusting assembly but still operates as it did with the parts in the conventional assembly, but at lower part and capital cost. The adjusting ring is constrained axially and radially by interaction with an inner diameter and an abutment provided in the upper vane ring of the vane pack.

Abstract: An arrangement is provided for controlling a variable position of vanes at a turbine in a flow channel of a turbine. The arrangement includes a nozzle ring carrying a set of vanes, each of the vanes being connected to a vane pin housed in the nozzle ring. A rotational position of the vanes is accomplished via a vane displacement drive train including a pivotally supported pivot axle, a first actuator arm arranged on the pivot axle, which first arm is connectable to a drive actuator, a second actuator arm arranged on the pivot axle, which second arm is connected to a pin engaged with an unison ring for pivoting the unison ring, and a vane arm being connected to each vane pin and the unison ring for displacement of the vanes via pivotal displacement of the unison ring, and wherein a stop screw is arranged for limiting the pivotal displacement of the vanes.

Abstract: A compressor comprises an impeller wheel mounted within a housing defining an inlet and an outlet. The wheel has a plurality of vanes and is rotatable about an axis. The housing has an inner wall defining a surface located in close proximity to radially outer edges of the impeller vanes which sweep across said surface as the impeller wheel rotates about its axis. The inlet comprises a tubular wall extending away from the impeller wheel in an upstream direction. An enclosed chamber is defined between said inner wall and an outer wall and in communication with at least one opening in said in said inner wall. The outer wall is penetrated by at least one ventilation aperture that is designed to be connected via a conduit to a location upstream of the inlet and downstream of an air filter.

Abstract: The invention relates to an exhaust-gas turbocharger (1) having a turbine (2), and having a compressor (3) which has a compressor housing (10), said compressor housing (10) being fastened to a bearing housing (4) and having a compressor spiral (13) and a bearing-housing-side diffuser wall (14), wherein the compressor housing (10) is formed as a pressure-die-cast housing, and the diffuser wall (14) is formed as a separate component which can be connected to the compressor housing (10) and which has an internal rounding (16) in the transition region to the inner wall of the compressor housing spiral (13).

Abstract: According to an aspect of the present invention, there is provided a turbocharger assembly, comprising: a turbocharger; one or more actuators for controlling a flow of fluid in, around, or associated with the operation of the turbocharger; control electronics for use in controlling actuation of the one or more actuators; and boost electronics configured to receive an input voltage, and to provide a boosted output voltage to the control electronics.

Abstract: Exemplary embodiments of the present invention are directed towards an apparatus and method for fluidly coupling a turbocharger to an internal combustion engine. In one embodiment, a turbocharger mount for fluidly coupling a turbocharger to an exhaust system of an engine is provided. The turbocharger mount includes a housing portion and a mounting flange extending from the housing portion. The housing portion defines a cavity therein and a first inlet opening in fluid communication with the cavity, a first outlet opening in fluid communication with the cavity, and a second outlet opening in fluid communication with the cavity.

Abstract: Exemplary embodiments of the present invention are directed towards a turbocharger for an internal combustion engine and more particularly an apparatus and method for fluidly coupling a turbocharger with an internal combustion engine. In one embodiment a turbocharger housing is provided. Turbocharger housing includes a turbine housing defining a volute chamber. The turbocharger housing also includes a first housing support extending from the turbine housing. The first housing support is integrally formed with the turbine housing and the first housing support defines an inlet opening and an outlet opening each of which are in fluid communication with the volute chamber.

Abstract: A moving-air energy recovery system including an air horn having serially disposed segments of differing flare rates, which intercepts a large area of moving air to channel and transform the flow of moving air into a more concentrated, higher velocity of air flow. This higher velocity air flow is applied to turbine vanes which are connected to an armature that provides a mechanical energy output from the incident air flow on a rotating shaft. In one embodiment, the shaft is connected to a electric generator to generate electric power, which may be applied to stationary applications such as emergency home power, and to mobile applications such as augmenting automobile propulsion.

Abstract: A supercharger includes a housing, and a turbine shaft supported in a center hole in the housing through rolling bearings. Lubricating oil for the rolling bearings exists only within the housing. A cooling water jacket is provided within a body portion of the housing over a region from one axial end portion of the body portion to the other axial end portion thereof.

Abstract: A non-positive-displacement machine (10), particularly a turbomachine for producing a mass flow, having a central housing part (11) inside which a turbine shaft is mounted. A turbine housing is mounted on the central housing part (11) on a turbine side and a compressor housing is mounted on the central housing part (11) on a compressor side. The spiral channels (17, 18) required for the compressor side and for the turbine side can be arranged in a partial area inside the covers (15, 16) and at least in one partial area inside the central housing part (11). This permits the contours, which are required for the spiral channels (17, 18) and which are geometrically complex, to be constructed in the central housing part (11).

Abstract: Disclosed is a pump for controllably dispensing an additive into a stream of liquid and mixing therewith, the pump comprising: a pump body having a passage into which a liquid stream is introduced, and from which a combination mixture of the additive and the liquid stream is discharged; a turbine supported for rotation within the passage, the incoming liquid stream striking the turbine in a manner as to impart rotation thereon; an auger housing connected to the pump body, and having an entrance end into which an additive is introduced and an exit end from which the additive is discharged into the passage, such that the additive mixes with the incoming liquid stream; and a helical lifting auger mounted on a supporting drive shaft fixedly attached to the turbine, the auger rotatably disposed within the auger housing so as to produce a fluid flow through the auger housing, the lifting auger configured to accept the additive from the auger housing entrance end; and move the additive through the auger housing to t

Abstract: An exhaust gas turbocharger, comprising: a turbine rotor rotatably mounted in a housing, which is associated with at least one guide apparatus forming a radial inlet channel, wherein the guide apparatus includes at least one of a guide vane bearing ring, a plurality of guide vanes radially surrounding the turbine rotor and located in the inlet channel and a guide vane cover ring. The inlet channel is axially delimited by the guide vane bearing ring and the guide vane cover ring wherein the guide vane bearing ring and the guide vane cover ring are moveably mounted at least one of axially and radially relative to each other and to the housing. The guide apparatus is subjected to at least one of an axial and radial preload, wherein a line of axial preload flux runs through the guide apparatus substantially parallel to the rotational axis of the turbine rotor.

Abstract: A turbocharger unit for an internal combustion engine having at least one exhaust line for the evacuation of exhaust gases from the combustion chamber of the engine and at least one inlet line for the supply of air to the combustion chamber is provided. The turbocharger unit includes a turbine which interacts with a compressor in order to extract energy from the exhaust-gas flow of the engine and pressurize the inlet air of the engine. The compressor is of the radial type and is provided with an impeller having backswept blades in which the blade angle between an imaginary extension of the center line of the blade between root section and tip section in the direction of the outlet tangent and a line connecting the center axis of the impeller to the outer tip of the blade is at least about 40 degrees. The ratio between the inlet diameter of the impeller and its outlet diameter lies within the range 0.50-0.62.

Abstract: An environmental control system includes a RAM air fan system downstream of a respective heat exchanger in the relatively high temperature RAM exhaust. The RAM air fan includes a RAM air fan electric motor such that the RAM air fan is driven at a speed independent of an air cycle machine. A fan rotor is completely supported by hydrodynamic foil journal and thrust bearings. As the RAM air fan is driven by the RAM air fan electric motor the RAM air fan is installed in the environmental control system as a self-contained system.

Abstract: A moving-air energy recovery system including an air horn having serially disposed segments of differing flare rates, which intercepts a large area of moving air to channel and transform the flow of moving air into a more concentrated, higher velocity of air flow. This higher velocity air flow is applied to turbine vanes which are connected to an armature that provides a mechanical energy output from the incident air flow on a rotating shaft. In one embodiment, the shaft is connected to a electric generator to generate electric power, which may be applied to stationary applications such as emergency home power, and to mobile applications such as augmenting automobile propulsion.

Abstract: A fluid machine includes a casing, a compression mechanism for compressing refrigerant, an expansion mechanism for expanding refrigerant, and a rotary shaft connecting the compression mechanism and the expansion mechanism The compression mechanism, the expansion mechanism and the rotary shaft are disposed in the casing. A heat insulator partitions an internal space of the casing into a first space with the expansion mechanism disposed therein and a second space with the compression mechanism disposed therein. The rotary shaft passes through the heat insulator. An elastically deformable seal element seals a clearance between an outer periphery of the heat insulator and an inner periphery of the casing.

Abstract: Bearing systems for high speed rotating shafts, such as turbocharger shafts, include a first ball bearing in one end of an elongated cylinder capable of carrying axial thrust in both directions and a second ball bearing in the opposite end of the elongated cylinder with its outer race slideably mounted in the cylinder against the biasing force of a preload spring. The second ball bearing is free to move axially with the shaft upon axial expansion of the shaft when exposed to high temperature. The inner races of the ball bearings are clamped to and rotate with the shaft as part of the rotating assembly.

Abstract: A pump system for testing an isolated zone in a borehole includes a testing pump and a testing device. The testing pump may be configured to at least assist in creating a formation fluid flow from the isolated zone in the borehole. The testing pump may be powered by a power fluid, where the power fluid may be delivered from a power fluid source. The power fluid source may be located at a location remote from the testing pump. The testing device may be configured to monitor the formation fluid flow. The testing device may further be configured to determine characteristics of the isolated zone in the borehole based at least in part on the monitored formation fluid flow.

Abstract: A turbocharger is disclosed that includes a compressor, a turbine connected to the compressor by a mechanical shaft, and a fluidic drain valve in flow communication with an air bleed port of the compressor and an exhaust plenum to drain water accumulated inside the turbocharger such that water accumulated in the exhaust plenum is drained during shutdown when no air from the bleed port flows through the fluidic drain valve.

Abstract: An exemplary anisotropic member (625, 1200, 1600, 1700, 1800, 1950) supports a bearing in a bore and can reduce non-synchronous vibration (NSV) of the bearing in the bore. An exemplary anisotropic member includes an annular body configured to receive a bearing and to space the bearing a distance from a bore surface and is configured to impart anisotropic stiffness and damping terms to the bearing when positioned in the bore. Such a member is suitable for use in a rotating assembly for a turbocharger where the bearing may be a floating bearing, a semi-floating bearing or a ball bearing. Various exemplary members, bearings, housings, assemblies, etc., are disclosed.

Abstract: An exemplary method for limiting movement of an outer race of a bearing cartridge includes positioning the bearing cartridge in a substantially cylindrical bore having a longitudinal axis, an inner diameter exceeding an outer diameter of the outer race, a proximate end and a distal end; limiting axial movement of the outer race at the distal end of the cylindrical bore with a counterbore substantially coaxial to the cylindrical bore and having an inner diameter less than the outer diameter of the outer race; limiting axial movement of the outer race at the proximate end of the cylindrical bore with a plate positioned substantially orthogonal to the longitudinal axis; and limiting rotation of the outer race with a pin positioned in a pin opening accessible via a lubricant drain. Various exemplary bearing cartridges, housings, assemblies, etc., are also disclosed.

Abstract: A coolant pump for processing machinery includes a housing, a water guide member, and a drive device. The housing includes a chamber, a wind inlet, and a wind outlet. The water guide member includes a hollowed portion, a water inlet, and a water outlet. The drive device includes a transmission shaft, a pumping member, and a blade assembly. The pumping member is mounted in the hollowed portion of the water guide member and to the other end of the transmission shaft. The blade assembly is mounted to the other end of the transmission shaft and located in the chamber of the housing. The coolant pump is highly safe and of long working life because it is powered by the air pressure and it is structurally simple and durable.

Abstract: An electric motor cartridge comprises a first cartridge housing portion (2) and a second cartridge housing portion (3). The cartridge housing portions (2, 3) are coupled together so as to assembly the electric motor cartridge (1) by radially and axially positioning a stator (4) there between.

Abstract: A turbocharger includes a turbine wheel, a compressor wheel connected thereto, an electric motor situated on the side of the compressor wheel which is distant to the turbine wheel, and a rotor connected to the compressor wheel in a rotationally fixed manner and designed in a freely projecting manner. A drive system for motor vehicles includes a turbocharger. The turbocharger is characterised by a very spontaneous response behaviour, as well as the possibility for energy recovery.