Abstract: The invention provides a method for purification of exhaust gas from a diesel engine in a system, which comprises a device for selective catalytic reduction and a diesel particulate filter preferably at least partially covered by a catalytic layer installed downstream of the device for selective catalytic reduction. A device for catalytic oxidation is installed upstream of the device for selective catalytic reduction and/or between the device for selective catalytic reduction and the diesel particulate filter. A device for injection of a controlled amount of reductant is installed inlet of the device for selective catalytic reduction, and a device for injection of a controlled amount of hydrocarbon is installed inlet of the catalytic oxidation.

Abstract: A method of operating components for exhaust gas after-treatment disposed in the exhaust gas tract of a turbocharged internal combustion engine. A partial exhaust gas stream is removed from the main exhaust gas stream upstream of at least one exhaust gas turbine. The partial exhaust gas stream is fed back into the main exhaust gas stream downstream of the at least one exhaust gas turbine. The feed is located, in terms of exhaust flow, between an NO oxidation catalytic converter and a particle filter (i.e., the exhaust gas after-treatment component). That is, the at least one exhaust gas after-treatment component is arranged downstream of the feed. The quantity of exhaust gas branched off as a partial exhaust gas stream is controlled or closed-loop controlled as a function of at least one target temperature in at least one defined point in the exhaust gas tract, in particular in the partial exhaust gas stream and/or of the at least one exhaust gas after-treatment component.

Abstract: Various methods and systems are provided for a vehicle with an engine. In one example, a method includes identifying an approaching tunnel. The method further includes, responsive to a particulate load of a particulate filter, the particulate filter disposed in an exhaust treatment system of an engine of the vehicle, initiating regeneration of the particulate filter at a selected distance before the tunnel such that regeneration is performed before the vehicle enters the tunnel.

Abstract: A method of operating an internal combustion engine having a reductant delivery and storage system in an emission control system is disclosed. The method includes an approach for reducing thermal damage to aftertreatment devices in an exhaust system by reducing excessive exhaust gas temperatures created during particulate filter regeneration.

Abstract: A control system of an internal combustion engine in which a first fuel of ammonia and a second fuel which is easier to burn than ammonia are used as fuels. An ammonia ratio is usually set to a reference ammonia ratio which is determined in advance in accordance with an operating state of an engine. At the time when feed of the fuel is restarted after suspension of feed of the fuel at the time of deceleration, the ammonia ratio is temporarily made lower than the reference ammonia ratio in accordance with the operating state of the engine.

Abstract: A system for treating an exhaust stream from an engine includes a main exhaust passageway adapted to receive the exhaust stream from the engine. A side branch is in communication with the main exhaust passageway. A regeneration unit is positioned within the side branch for combusting a fuel and heating the exhaust flowing through the main exhaust passageway. A lean NOx catalyst is positioned within the main exhaust passageway downstream of the regeneration unit. A reductant injector is positioned downstream of the regeneration unit and upstream of the lean NOx catalyst to inject reductant particles into the exhaust stream. A controller operates the regeneration unit to increase the exhaust temperature as well as operates the reductant injector to reduce NOx within the lean NOx catalyst.

Abstract: A static mixer for the through-mixing of a flow in a line conducting the flow, more preferably of an exhaust system of a combustion engine with several guide vanes. To create adequate through-mixing at low flow velocity and a through-flow resistance that is not too high at high flow velocity, the guide vanes are produced of a shape memory alloy wherein below a predetermined limit temperature the guide vanes have at least one low-temperature shape and above the limit temperature the guide vanes have at least one high-temperature shape, which differs from the low-temperature shape through a reduced through-flow resistance of the mixer.

Abstract: An exhaust system for a vehicle having a cab (53) and an internal combustion engine (1) located in an engine compartment (51). The system includes an exhaust gas treatment unit (9) located outside the engine compartment and having an inlet (9a) which receives exhaust gases from the engine and an outlet (9e) which passes treated gases into a final portion (E) of the exhaust system. The treatment unit (9) is arranged to extend generally vertically with the outlet (9e) generally vertically above the inlet (9a) and adjacent a corner post (52) of the cab of the vehicle to reduce impact on the visibility from the cab. A cage (C) surrounds the exhaust gas treatment unit (9) and has a support means (12) for attachment to a chassis of the vehicle and an outlet (15e) which the outlet (9e) of the treatment unit is connected.

Abstract: When the cut-off cylinder operation execution condition of a multi-cylinder internal combustion engine is fulfilled, the temperature of the catalytic converter provided in the exhaust passage linked to the cylinders that are made inoperative during the cut-off cylinder operation is estimated, and when this temperature is less than the predetermined preliminary heating requiring temperature, a catalyst preliminary heating operation is executed by which the ignition timing of the cylinders is delayed and the temperature of the catalytic converter is raised. Then, the cut-off cylinder operation is started after the temperature of the catalytic converter becomes equal to or higher than the preliminary heating requiring temperature.

Abstract: Diesel exhaust fluid systems are provided. The diesel exhaust fluid systems include a fluid reservoir having an inner surface and an opening therethrough, a fluid reservoir heating device positioned within the fluid reservoir, and a fluid reservoir spacer positioned within the fluid reservoir and between the inner surface of the fluid reservoir and the fluid reservoir heating device.

Abstract: In various embodiments, compressed-gas energy storage and recovery systems include a cylinder assembly for compression and/or expansion of gas, a reservoir for storage and/or supply of compressed gas, and a system for thermally conditioning gas within the reservoir.

Abstract: A method of combining outputs of a plurality of fluid pumps includes receiving an input signal from an input device. The input signal is adapted to control a function of a work vehicle. An actuation signal is sent to a first direction control device of a first actuator assembly. The first actuator assembly is in selective fluid communication with a first pump assembly. A position of a second direction control valve of a second actuator assembly is received. The second actuator assembly is in selective fluid communication with a second pump assembly. A selector valve that is in fluid communication with a cavity of a poppet valve assembly is actuated so that the second pump assembly is in fluid communication with the first actuator assembly when the second direction control valve is in a neutral position.

Abstract: A hydraulic motor 100 includes a switching valve 3 which is connected to a pilot passage 54 by which a pressure fluid is introduced into a back pressure chamber 21 of a relief valve 2 and takes a first changeover position 3a where the back pressure chamber 21 is connected to a tank 102 or a second changeover position 3b where the pilot passage 54 is connected to the back pressure chamber 21. By this switching valve 3, the pressure fluid supplied to a hydraulic motor mechanism 1 is introduced into the back pressure chamber 21 via the pilot passage 54 when the hydraulic motor mechanism 1 is in operation, whereas the back pressure chamber 21 is connected to the tank 102 as the pressure in the pilot passage 54 becomes not higher than a predetermined pressure when the hydraulic motor mechanism 1 is being braked.

Abstract: An articulated dump truck is provided with an electro-hydraulic bin control system including a proportional control valve for the bin lift cylinders and including a solenoid-operated regenerative valve assembly mounted adjacent the lift cylinders and being actuated, during lifting the bin for dumping a load of material from the bin, to cause a regenerative flow to occur when the force required by the bin lift cylinders to continue lifting the bin falls to a predetermined force. The force required for tilting the bin is continuously calculated by an electronic control unit taking into account a sensed bin load, a sensed bin tip amount and a sensed side-to-side inclination of the bin.

Abstract: A steering system includes a fluid motor and a steering unit. The steering unit is in fluid communication with the fluid motor. The steering unit includes a fluid meter adapted to meter fluid to the fluid motor in response to actuation of the steering unit. A valve housing is in fluid communication with the fluid meter. The valve housing defines a valve bore. A valve assembly is disposed in the valve bore. The valve assembly defines a primary fluid path to the fluid meter and to the fluid motor from the fluid meter. The valve assembly further defines a secondary fluid path to the fluid motor that bypasses the fluid meter. An amount of fluid through the secondary fluid path is based on volumetric efficiency of the fluid motor.

Abstract: A method of operating a variable geometry turbine (VTG) during transient operations for maximum response by determining the VTG area at the balance condition of the pressure ratio and efficiency curves for the variable geometry turbine to achieve maximum power. The method includes measurements of turbine inlet pressure, turbine outlet pressure, turbine rpm, and other parameters used to measure turbine mass flow.

Abstract: A valve and cylinder head assembly, configured to fit a bank of cylinders of an internal combustion engine, can include a first exhaust valve for each corresponding cylinder of the bank of cylinders; a second exhaust valve for each corresponding cylinder of the bank of cylinders; a first exhaust port for each corresponding cylinder of the bank of cylinders, the first exhaust port configured to direct flow of exhaust to a first manifold in fluid communication with a first turbocharger; and a second exhaust port for each corresponding cylinder of the bank of cylinders, the second exhaust port configured to direct flow of exhaust to a second manifold in fluid communication with a second turbocharger; where the shape of the first exhaust ports differs from the shape of the second exhaust ports; where each of the first exhaust valves controls flow of exhaust to a respective one of the first exhaust ports; and where each of the second exhaust valves controls flow of exhaust to a respective one of the second exhaust

Abstract: In an exhaust gas turbocharger for an internal combustion engine having a turbine housing for receiving a turbine wheel, having a guide device having guide elements for influencing flow parameters in a turbine wheel inlet area, a displaceable adjusting device associated with the guide device, and also a contour sleeve element for influencing flow parameters in a turbine wheel outlet area, the guide device, the contour sleeve element, and the adjusting device are inserted as a subassembly into the exhaust gas turbocharger housing via the turbine outlet area and firmly mounted in the turbine housing.

Abstract: A variable-nozzle turbocharger includes a turbine housing and a center housing, and a generally annular nozzle ring and an array of vanes rotatably mounted to the nozzle ring such that the vanes are rotatably adjustable for regulating exhaust gas flow to the turbine wheel. An elastically deformable member is disposed between a radially inwardly facing surface of the nozzle ring and a radially outwardly facing surface of the center housing, the elastically deformable member having a radially inner surface contacting the radially outwardly facing surface of the center housing and having a radially outer surface contacting the radially inwardly facing surface of the nozzle ring so as to radially center the nozzle ring relative to the center housing.

Abstract: Various systems and methods are described for an exhaust gas recirculation (EGR) system coupled to an engine in a vehicle. One example method comprises, calculating an EGR mass flow from a difference between measurements of clean air mass flow and total mass flow, and correcting for a transient mass flow error.

Abstract: A combined cycle power system is provided including at least one solar power plant including a concentrating dish configured to concentrate solar radiation; a solar receiver disposed and configured to utilize concentrated solar radiation for heating a first working fluid, and a first turbine configured for generating electricity by expansion therein of the heated first working fluid, and at least one recovery power plant including a heat recovery unit configured for utilizing exhaust heat of the first turbine to heat a second working fluid, and a second turbine configured for generating electricity by expansion therein of the heated second working fluid.

Abstract: An apparatus that harnesses the thermal energy of spent fuel rods in nuclear power plants to power the cooling system of the nuclear power plant particularly the cooling for the spent fuel rod storage ponds and the main reactors. The apparatus is comprised of a heat exchanger unit that accumulates the thermal energy of the spent fuel rods, a heat conveyance system that conveys the thermal energy of the spent fuel rods, and a heat engine that receives its thermal energy input from the spent fuel rods and produces mechanical power that runs an electrical generator which powers the cooling system of the nuclear power plant, particularly the controls and pumps that cool the spent fuel rod storage ponds and the main reactors. The apparatus provides a redundant power source and makes the cooling system of nuclear power plants independent of externally supplied electrical power and thereby resolves a key redundancy and safety concern with nuclear power generation.

Abstract: A turbine wheel is rotatable in response to expansion of a working fluid flowing from near an inlet side towards an outlet side of the turbine wheel. The turbine wheel may receive the working fluid radially into the inlet side of the turbine wheel and output the working fluid axially from its outlet side. A generator has a stator and a rotor. The rotor may be coupled to the turbine wheel and may rotate at the same speed as the turbine wheel when the turbine wheel rotates. In certain instances, the generator is adjacent the inlet side of the turbine wheel.

Abstract: A HRSG for fluidized bed gasification comprises a high temperature evaporator (200), a superheater (300), a low temperature evaporator (400), and an economizer (500) in series. The superheater (300), the low temperature evaporator (400) and the economizer (500) have water-tube structure, and the high temperature evaporator (200) has fire-tube structure.

Abstract: A boiling water nuclear power plant supplies steam from a reactor to high-pressure and low-pressure turbines. Water (feed water) generated by condensing steam in a condenser is heated by low-pressure and high-pressure feed water heaters and supplied to the reactor. The steam discharged from the low-pressure turbine is compressed by a steam compression apparatus (a heat pump) and supplied to one of the low-pressure feed water heaters to heat feed water. The steam extracted from the low-pressure turbine is also supplied to the low-pressure feed water heater. When power required for the steam compression apparatus is Q1, heat energy supplied from the steam compression apparatus is Q3, a coefficient of performance of the steam compression apparatus is COP )(=Q3/Q1), and a thermal efficiency of the boiling water nuclear power plant is ?, the steam compression apparatus is connected to a position in a main steam system and to the feed water heater so as to satisfy COP?1/?>0.

Abstract: Methods, systems, and apparatus for generating energy from a process contained series of explosion cycles is provided. The Explo-Dynamics™ energy generating system includes several embodiments for stimulating the heat and pressure release episodes of the process configurations and translating the released forces into torque, thrust, motive force, and/or super-heat impulses. The methods and systems of the present invention include a comprehensive arrangement of process configurations and components as well as a means of operation.

Abstract: A method for assembling a fuel supply system for use with a power generation system. The method includes coupling a fuel heater to a fuel source for heating a fuel. A first heating assembly is coupled to the fuel heater for heating a first flow of water channeled to the fuel heater. A heat recovery steam generator assembly is coupled to the fuel heater for channeling a second flow of heated water to the fuel heater. A valve assembly is coupled between the first heating assembly, the heat recovery steam generator assembly, and the fuel heater to enable a flow of heated water from the first heating assembly and the heat recovery steam generator assembly to be selectively channeled to the fuel heater.

Abstract: An air cooling hood offset from an exterior of the transition piece to define an air cooling passage between the air cooling hood and the exterior of the transition piece, wherein the air cooling hood comprises a plurality of air outlets disposed along the exterior of the transition piece, and the plurality of air outlets is configured to expel an airflow from the air cooling passage away from the exterior of the transition piece.

Abstract: A method for utilizing landfill gas is disclosed herein. The method includes the step of collecting landfill gas. The method also includes the step of fueling a turbine engine that is at least part of a power generation system with the landfill gas to generate power. The method also includes the step of cooling one or more components of the power generation system with the landfill gas prior to the fueling step. A power generation system capable of practicing the method is also disclosed. A landfill gas utilization system capable of practicing the method is also disclosed.

Abstract: A method and a power plant for combustion of carbonaceous fuel for production of electrical power are described. The plant is a pressurized fluidized bed combustion plant wherein the compressor(s) (5, 5 . . . ) for compression of the air for the combustion is (are) arranged on shafts being separate from the shafts for the expander(s) (29) for expanding the combustion gas.

Abstract: A synthesis gas-based fuel system with a main synthesis gas pipe which branches off a gasification device and ends at a transfer point is described. The main gas pipe is connected to a burner. A device for admixing a second fuel and, downstream there from in a direction of flow of a synthesis gas, a mixing device are arranged within the main synthesis gas pipe. Further, a method for operating the synthesis gas-based fuel system for rapid load changes in a synthesis gas-operated gas turbine is provided.

Abstract: A gas turbine component includes an element having a relatively weak region with regard to stress loads in operation, the component including at least one elongated stiffening structure which extends on at least one side of the weak region, and the elongated stiffening structure is connected to the element in a load-transmitting manner and adapted to form a load path in its extension direction.

Abstract: A device for producing electrical power in a gas turbine or the like of an aircraft, the device including a plurality of thermoelectric cells having a face surrounding a hot source. A cold source is constituted by a cold fluid flowing over the other face of the thermoelectric cells.

Abstract: A system (10) for cooling a heat exchanger (12) on board an aircraft comprises a process air line (28), a first end of which is connected to an engine (16) of the aircraft in order to supply engine bleed air to the process air line (28). A second end of the process air line 28 is connected to a turbine (30) in order to supply the engine bleed air flowing through the process air line (28) to the turbine (30). A first end of a cooling air line (34) is connected to the turbine (30) in order to supply the cooling air line (34) with cooling air that is produced by expansion of the engine bleed air in the turbine (30). The cooling air line (34) is adapted to supply the cooling air flowing through the cooling air line (34) to the heat exchanger (12) that is to be cooled.

Abstract: A refrigerated point-of-use food holding cabinet keeps food products cold in compartments having cross sections that are substantially U-shaped. Food products are kept refrigerated using heat-absorbing, heat-exchangers thermally coupled to the U-shaped compartment. Refrigeration is provided by either a conventional reversed-Brayton cycle, one or more Peltier devices or a chilled, re-circulating liquid that does not change phase as it circulates but which is chilled by another refrigeration system, such as a conventional refrigeration system. An optional cover helps prevent food flavor transfers between compartments. Semiconductor temperature sensors and a computer effectuate temperature control.

Abstract: A temperature adjustment apparatus suppresses decline in temperature adjustment performance by avoiding even partial impairment of the function of a thermoelectric module in respective zones, which is accomplished due to the presence of terminals. A terminal is provided via an electrode extension section on a heat exchange plate side electrode of the thermoelectric module of inner zones apart from an outermost zone, of four zones. The electrode extension section is disposed at a position which is sandwiched between adjacent thermoelectric elements and over which a temperature adjustment side electrode spans. The terminals are disposed outside the thermoelectric module in the outermost zone.

Abstract: A refrigeration system includes a cryogenic freezer and a mechanical refrigerator, wherein the mechanical refrigerator includes an enclosure containing an atmosphere, the cryogenic freezer includes a cryogen exhaust conduit, and a heat pipe heat exchanger including a warm end and a cold end, wherein the heat pipe heat exchanger is in heat transfer relationship with the mechanical refrigerator and the cryogenic freezer such that the warm end of the heat pipe heat exchanger contacts the atmosphere within the mechanical refrigerator enclosure, and the cold end of the heat pipe heat exchanger is disposed within the cryogen exhaust conduit of the cryogenic freezer. A refrigeration process includes cooling an atmosphere within a mechanical refrigerator by exposing the atmosphere to a warm end of a heat pipe heat exchanger, wherein a cold end of the heat pipe heat exchanger is disposed within an exhaust duct of a cryogenic freezer.

Abstract: A cryogenic refrigeration system for lyophilization is disclosed. The cryogenic refrigeration system includes a cryogenic heat exchanger system adapted for vaporizing a liquid cryogen and using the gaseous cryogen to cool heat transfer fluid and a heat transfer cooling circuit that cools the lyophilization chamber as well as the condenser. The disclosed heat transfer cooling circuit includes a primary recirculation loop adapted for cooling the lyophilization chamber with the heat transfer fluid, a secondary recirculation loop adapted for cooling a condenser with the heat transfer fluid, and one or more valves operatively coupling the cryogenic heat exchanger system, the primary recirculation loop, and the secondary recirculation loop.

Abstract: A heat-source system includes centrifugal-chillers, cooling-water pumps, cooling towers, cooling-tower fans, chilled-water pumps, and a control unit for controlling them. A plurality of the cooling towers are provided so as to have a cooling-tower capacity corresponding to the total capacity of the rated capacities of the respective centrifugal-chillers, the cooling towers being commonly connected to the plurality of centrifugal-chillers. The control unit preliminarily prepares an optimum cooling-tower capacity relationship representing the cooling-tower capacity with which the heat-source system efficiency, taking into consideration the centrifugal-chillers, the cooling-water pump, the cooling towers, the cooling-tower fan, and the chilled-water pump, is higher, in relation to the outside-air wet-bulb temperature and the centrifugal-chiller partial load factor.

Abstract: The fan of a refrigeration machine operatively connected to a container box is operated in one direction during normal operation and is periodically operated in the opposite direction in order to reverse the direction of airflow to and from the container box so as to thereby promote a more uniform temperature distribution within the container box. A door is automatically closed when operating in the reverse direction so as to accelerate the airflow speed into the container box.

Abstract: A system and method for transferring heat from a process source and dissipating it to the ambient atmosphere. The system uses a low-volatility, hygroscopic working fluid to reject thermal energy directly to ambient air. Direct-contact heat exchange allows for the creation of large interfacial surface areas for effective heat transfer. Heat transfer is further enhanced by water vapor pressure gradients present between the equilibrium moisture content of the working fluid and the ambient air. Cyclic absorption and evaporation of atmospheric moisture dampens variations in cooling capacity because of ambient temperature changes. The low-volatility and hygroscopic nature of the working fluid prevents complete evaporation of the fluid and a net consumption of water.

Abstract: A transport refrigeration system with a direct drive compressor arrangement is provided with a variable speed electrically driven booster compressor that operates in series with the direct drive compressor. The speed of the booster compressor is controlled to either boost or decrease the system capacity. The booster compressor also acts to regulate the flow of refrigerant from the evaporator during periods of operation in which the direct drive compressor might otherwise become overloaded.

Abstract: The present invention discloses an evaporative cooling clothing system for reducing body temperature of a wearer of the clothing system. The clothing system includes a clothing article configured using a wicking fabric and a hollow transport defining a cavity for transporting a liquid from a liquid reservoir to an upper region of the clothing article. The hollow transport has an intake section and a dispensing section. The intake section is attached to the liquid reservoir for receiving the liquid, and the dispensing section is attached to the upper region of the clothing article. The upper region of the clothing article receives the liquid from the dispensing section and transfers the liquid to a lower region of the clothing article. The lower region of the clothing article exposes the liquid to an environment surrounding the clothing article for evaporation.

Abstract: A refrigeration cycle apparatus (100A) is provided with: a first compressor (1) including a first compression mechanism (11), an expansion mechanism (13), and a first motor (12); a second compressor (2) including a second compression mechanism (21), and a second motor (22); and a control device (6). The control device (6) reduces a rotation frequency of the second motor (22) at a reduction speed greater than a rotation frequency of the first motor (12) in a stop operation for stopping the first motor (12) and the second motor (22) while reducing the rotation frequencies of the first motor (12) and the second motor (12).

Abstract: A refrigerator includes a freezing compartment and a door for selectively opening or closing at least a part of the freezing compartment The door includes a foam insulating layer and a sidewall contacting the foam insulating layer. A heater is installed correlative with the sidewall to supply heat to the sidewall.

Abstract: A hot water supply apparatus associated with a heat pump is provided. The hot water supply apparatus performs a hot water supply operation using a high temperature refrigerant that has been discharged from a compressor, and simultaneously performs an indoor heating operation using a two-stage refrigerant cycle. This allows the apparatus to supply hot water while simultaneously providing heating/cooling to an indoor space.

Abstract: A hot water supply apparatus associated with a heat pump is disclosed herein. The hot water supply apparatus may include a main refrigerant circuit that includes a compressor, an indoor heat exchanger, an expander, and an outdoor heat exchanger; a hot water supply circuit connected to the main refrigerant circuit; a first flowrate regulator that adjusts a first flowrate of refrigerant that flows from the compressor through the main refrigerant circuit; a second flowrate regulator that adjusts a second flowrate of refrigerant that flows from the compressor to the hot water supply circuit; and a controller configured to control the first and second flowrate regulators based on a load on at least one of the main refrigerant circuit or the hot water supply circuit.

Abstract: A household refrigerator having three compartments: a freezer compartment, a refrigerator compartment, and a condiment compartment. Each compartment is accessed via its own door. In an illustrative embodiment, the refrigerator compartment is above the freezer compartment and the condiment compartment is adjacent the refrigerator compartment on the side of the refrigerator. The condiment compartment preferably includes movable shelves inside the condiment compartment as well as on the door to the condiment compartment. One or more electric fans are provided to circulate cold air from the refrigerator compartment into the condiment compartment. The fans are preferably controlled by a thermostat. The refrigerator is preferably designed so that the condiment compartment may be mounted on either the left or right side of the refrigerator compartment.

Abstract: Provided is a water heater, which allows efficient deposition of a scale component dissolved in water so as to reduce adhesion of the scale to a heat-transfer channel. The water heater includes: scale deposition means including a tank, an anode and a cathode provided in the tank so as to be opposed to each other, and a first power supply for applying a voltage between the anode and the cathode, the scale deposition means depositing a scale component dissolved in water retained in the tank; a heat-transfer channel provided at downstream of the scale deposition means, for guiding the water; and a heat source for heating the water by heat exchange in the heat-transfer channel, in which the scale deposition means includes oxygen-gas supplying/dissolving means for supplying an oxygen gas to a water feed pipe for feeding the water to the tank and dissolving the oxygen gas in the water.

Abstract: The purpose of Energy Mist Shield is to protect refrigeration condenser coils from getting moisture during evaporative misting process and to protect condenser coils from damaging with harmful mineral deposits contained in water and to ensure the cleaning requirements of condensers such as dirt, leaves and debris.