Abstract: An after-treatment component detection system may include an exhaust system configured to include an after-treatment component configured to remove one or more constituents of the exhaust gases. The detection system may include an upstream temperature sensor configured to measure temperature upstream from the after-treatment component, a downstream temperature sensor configured to measure temperature downstream from the after-treatment component, and a controller. The controller may be configured to receive signals indicative of upstream temperature measurements from the upstream sensor and signals indicative of downstream temperature measurements from the downstream sensor and determine an upstream rate of temperature change and a downstream rate of temperature change.

Abstract: An oxidation catalyst temperature control system and method for an engine having an exhaust means including an oxidation catalyst is provided. A post fuel calculation means calculates a value representing a post quantity of fuel to be introduced to generate an exothermic reaction in the oxidation catalyst based on a pre-determined desired outlet temperature of the oxidation catalyst, the calculation using a steady state model of the oxidation catalyst, the steady state model utilising the exhaust mass flow rate and the inlet temperature of the oxidation catalyst and instruction means to instruct the post quantity of fuel to be introduced to the engine.

Abstract: A catalyst suitable for reducing NOx in exhaust gas by ammonia in the presence of excess oxygen is arranged in an engine exhaust passage. The catalyst is fed an aqueous urea solution from an addition control valve, part of the urea fed to the catalyst is stored in the catalyst, and the ammonia produced from the urea stored in the catalyst is used to reduce the NOx in the exhaust gas. It is judged whether the storage capacity of the catalyst is larger than a preset allowable upper limit capacity. When it is judged that the storage capacity of the catalyst is larger than the allowable upper limit capacity, the feed of the aqueous urea solution is prohibited.

Abstract: A combustion engine has in the exhaust gas area a SCR-catalyzer with a NH3-filling level, a metering device for supplying the SCR-catalyzer with reactant for reducing nitrous gases and at a downstream NH3-sensitive NOx-sensor. One theoretical value for the NOx downstream of the SCR-catalyzer is compared to an actual NOx-value downstream of the SCR-catalyzer. A reasonability check includes determining a first value for one comparison parameter, which represents the state before a system interference for adapting the NH3-filling level. A system interference for adapting the NH3-filling level is carried out and again a second value of the comparison parameter detected. From the comparison of the first value and the second value the reasonability, the non-reasonability or non-preciseness of the system interference is assumed.

Abstract: The invention concerns a procedure for controlling a metering device for metering fuel into the exhaust gas duct of a combustion engine for the regeneration of a particle filter, whereby the metering device supplies the fuel to the exhaust gas duct over a security valve, a first fuel pipe, a metering valve, a second fuel pipe and an injection check valve and whereby the pressure of the fuel is determined between the metering valve and the injection check valve in the second fuel pipe. It is thereby provided that an opening pressure of the injection check valve is determined from the pressure course between the metering valve and the injection check valve.

Abstract: A method of reducing NOx in a vehicle exhaust operating by alternating exhaust flow between two lean NOx traps and directing the emerging exhaust to a downstream SCR catalyst system. While exhaust predominantly flows through one of the lean NOx traps, a reductant is provided to the other NOx trap so as to produce ammonia that is also directed to the SCR catalyst system. An exhaust system implementing the method of the invention is also provided.

Abstract: A selective catalytic reduction (SCR) catalyst control system and method for an engine is disclosed. Urea injection to an SCR catalyst is determined based on an SCR catalyst model, which determines a value of stored NH3 in the SCR catalyst based on the NOx engine emission value, the SCR catalyst temperature, the quantity of urea supplied to the SCR catalyst and a pre-determined efficiency of conversion of NOx gases. A target value of stored NH3 and the value of stored NH3 in the SCR catalyst is then used to determine a stored NH3 differential, which is then used to calculate urea injection.

Abstract: Solid metal ammine complexes are applied for safe and high-density storage of ammonia to be released for use as reducing agent in selective catalytic reduction of NOx in exhaust gases or as an energy carrier for fuel cell applications. The compositional formula of the metal ammine complexes is M(NH3)nXz, where Mz+ represents one or more metal ions capable of binding ammonia, X represents one or more anions, n is the coordination number (from 2 to 12), and z the valency of the metal ion (and thus the total number of compensating anion charges). Ammonia is released by controlled dosing of water into the storage container whereby ammonia is released because water replaces ammonia on the active sites capable of binding ammonia. Consequently, ammonia can be released without applying a normal thermal desorption of ammonia and the operating temperature of the system is reduced as well as the energy needed for releasing ammonia.

Abstract: An apparatus for treating an exhaust gas feedstream from an internal combustion engine operating lean of stoichiometry comprises a particulate filter device comprising a porous substrate element having a hydrocarbon-selective catalytically reactive washcoat. The hydrocarbon-selective catalytically reactive washcoat comprises a silver-oxide catalytic material on an alumina-based washcoat. An injection device is operative to inject a hydrocarbon reductant upstream of the particulate filter device.

Abstract: Provided is a stainless steel for exhaust gas path members, which has a composition including, in terms of % by mass, at most 0.03% of C, at most 1% of Si, at most 1.5% of Mn, at most 0.6% of Ni, from 10 to 20% of Cr, from more than 0.5 to 0.7% of Nb, from 0.05 to 0.3% of Ti, from more than 1 to 2% of Cu, at most 0.2% of V, at most 0.03% of N, from 0.0005 to 0.02% of B, and optionally at most 0.1% of Al, and further optionally at least one of Mo, W, Zr and Co in an amount of at most 4% in total, with a balance of Fe and inevitable impurities, and which has a texture where the Cu phase and the Nb compound phase having a major diameter of at least 0.5 ?m are controlled to be in an amount of at most 10 grains/25 ?m2 each. The stainless steel exhibits excellent thermal fatigue resistance when applied to exhaust gas path members of both cases where the maximum ultimate temperature is high and low, and has excellent low-temperature toughness.

Abstract: The invention relates to an exhaust gas after treatment apparatus having a hollow cylindrical casing shell (2). In the inside an exhaust catalytic converter, preferably adapted as SCR-catalytic converter, as well as an inflow chamber (9) for exhaust gas to be purified are provided. Therein, the inflow chamber (9) is defined by two bottom portions (10, 11) arranged opposite to each other. Further, a shell portion (12) gas tightly encompassing the bottom portions (10, 11) is provided for the inflow chamber (9). The inflow chamber (9) is encompassed by the casing shell (2) and may be manufactured from a material different from a material of the casing shell. The exhaust gas after treatment apparatus (1) is suitable in particular for commercial motor vehicles having a diesel engine.

Abstract: Carbon nanotube material dispersed in a dense material such as ceramic can produce heating when exposed to microwave radiation (e.g., electromagnetic radiation in the frequency range of approximately 0.3 GHz to 300 GHz). By changing the loading of carbon nanotube material within a ceramic medium, one can affect the heating capability of the medium in dramatic and unpredicted fashion. This finding can be used to implement heating devices that heat via conduction or through radiation (e.g., infrared heating).

Abstract: A method of braking a hydrostatic drive machine includes steps of reducing a displacement of a pump of a hydrostatic drive system to a non-zero displacement, and increasing a displacement of a motor of the hydrostatic drive system to a displacement that is less than a maximum displacement. The method also includes a step of accelerating an engine of the hydrostatic drive system toward a desired engine speed range.

Abstract: A control system for a machine is disclosed. The control system may have a pump, a low pressure reservoir, and at least one actuator connected to receive fluid pressurized by the pump and discharge fluid to the low pressure reservoir. The control system may also have a bypass passage situated to allow fluid to bypass the at least one actuator, and a warmup valve disposed within the bypass passage and being movable between a flow-passing position and a flow-blocking position. The control system may further have a hydraulic temperature sensor configured to generate a signal indicative of a temperature of the fluid, and a controller in communication with the pump, the warmup valve, and the hydraulic temperature sensor. The controller may be configured to move the warmup valve to the flow-passing position, fix a displacement position of the pump, and adjust an input speed of the pump in response to the signal.

Abstract: A hydropneumatic accumulator with a flexible porous filler intended for fluid power recuperation in hydraulic systems with a high level of pulsations includes a shell where a gas port and a fluid port are connected, respectively, with a gas reservoir and a fluid reservoir of variable volume separated by a movable separator. The flexible porous filler fills the gas reservoir so that the separator movement reducing the gas reservoir volume compresses said filler. The filler is connected with internal walls of the gas reservoir with the possibility of stretching the filler at the separator movement increasing the volume of the gas reservoir. The accumulator contains means of protection of the filler boundary layer against rupture made with the possibility of reducing local deformations of the boundary filler layer in case of jerks of the separator.

Abstract: A hoseless hydraulic system is provided which addresses certain safety and efficiency issues known in the art. The hydraulic system includes a shell, an accumulator disposed within the shell, a hydraulic pump at least partly disposed within the shell, and at least one hydraulic motor at least partly disposed within the shell. High pressure fluid communication conduits are substantially located within the shell. The only communication across the shell boundary is mechanical power in, mechanical power out, control signals in, and sensor signals out.

Abstract: The invention relates to a hydrostatic drive having one hydraulic pump unit (3) and at least one first hydraulic motor unit (14) and a second hydraulic motor unit (15). The first hydraulic motor unit (14) and the second hydraulic motor unit (15) are connected in parallel with the hydraulic pump unit (3) in a hydraulic circuit. A flow divider (80) is provided between the two hydraulic motor units (14, 15) and the hydraulic pump unit (3). The first working line (7) connecting the flow divider (80) with the hydraulic pump unit (3) is connected to a pressure control valve (23).

Abstract: An axle driving apparatus includes a first housing having a plurality of cooling fins, an axle rotatably mounted in the first housing, a hydraulic stepless speed change assembly disposed within the first housing. The axle driving apparatus also includes a second housing having a plurality of cooling fins, an axle rotatably mounted in the second housing, a hydraulic stepless speed change assembly disposed within the second housing. A connecting means, such as a bar and/or plate connects the first and second housings. The plurality of cooling fins on the first housing has a different configuration that the plurality of cooling fins on the second housing.

Abstract: A transmission system of a vehicle comprises a pump, an auxiliary pump, and a transmission. The pump pressurizes transmission oil when an engine is operating. The auxiliary pump operably coupled to the pump and located parallel to the pump that pressurizes the transmission oil when the engine is not operating. The transmission selects a gear ratio based on the pressurized transmission oil.

Abstract: A hydraulic circuit associated with a hydraulic actuator is provided having a reservoir situated to hold a supply of fluid and a pump situated to supply pressurized fluid to the hydraulic actuator. The hydraulic circuit also has a pressure intensifying valve fluidly connected to the reservoir and the hydraulic actuator. The pressure intensifying valve is situated to direct fluid to the reservoir while in a first position and direct fluid to the hydraulic actuator while in a second position. The hydraulic circuit further has a flow divider including a housing with an inlet fluidly connected to the pump, a first outlet fluidly connected to the hydraulic actuator, and a second outlet fluidly connected to the pressure intensifying valve. The flow divider also includes a first fluid transporting portion fluidly connected to the inlet and the first outlet and a second fluid transporting portion fluidly connected to the inlet and the second outlet.

Abstract: Devices and methods for moving a working fluid through a controlled thermodynamic cycle in a positive displacement fluid-handling device (20, 20?, 20?) with minimal energy input include continuously varying the relative compression and expansion ratios of the working fluid in respective compressor and expander sections without diminishing volumetric efficiency. In one embodiment, a rotating valve plate arrangement (40, 42, 44, 46) is provided with moveable apertures or windows (48, 50, 56, 58) for conducting the passage of the working fluid in a manner which enables on-the-fly management of the thermodynamic efficiency of the device (20) under varying conditions in order to maximize the amount of mechanical work needed to move the target quantity of heat absorbed and released by the working fluid. When operated in refrigeration modes, the work required to move the heat is minimized. In power modes, the work extracted for the given input heat is maximized.

Abstract: The invention relates to a method for the environmentally sound disposal of air/solvent mixtures made of combustible gaseous, vaporous or liquid waste products, using a combustion unit for burning the air/solvent mixtures while removing the environmentally compatible exhaust air developing in the combustion unit and the waste heat that is produced.

Abstract: A system to cool exhaust gas entering a catalytic converter in a turbocharged engine is disclosed. An air bypass valve is controlled to vent pressurized air to the atmosphere to overrev a turbocharger when exhaust gas exceeds a predetermined temperature. The rotation of the turbocharger increases to maintain a desired boost pressure. When this occurs, the turbocharger absorbs more energy from the exhaust gas to maintain the desired boost pressure. Thus, the exhaust gas entering the catalytic converter is cooled.

Abstract: A method of operating an internal combustion engine having an intake, an exhaust, and a turbocharger including a turbine and a compressor, the compressor coupled to the intake and the turbine coupled to the exhaust, the engine further having an exhaust gas recirculation system coupled to the exhaust upstream of the turbine and coupled to the intake downstream of the compressor, the method including transferring heat via a heat exchanger from the exhaust gas recirculation system to downstream of the turbine.

Abstract: A work machine having an internal combustion engine such as a diesel is connected to a transmission by a flexible coupling. The engine may have a turbocharger to increase its output. A power turbine is connected to receive exhaust products from the turbocharger turbine via an exhaust aftertreatment device. The power turbine is connected to either the transmission downstream of the flexible coupling or to an external load. In either case, the power turbine in the form of a centripetal turbine is isolated from the torsional vibrations of the IC engine.

Abstract: In an exhaust-gas turbocharger with a shaft axially arranged between a compressor wheel and a turbine wheel and connected in a rotationally fixed manner to the compressor wheel as well as to the turbine wheel, said shaft being rotationally mounted with a turbine-side shaft part in a turbine-side bearing, a connecting region with minimal heat conductivity is axially arranged or configured between the turbine-side shaft part and the turbine wheel in such a manner that the heat flow emanating from the turbine wheel is choked.

Abstract: A method of heating an engine exhaust gas of an engine, including flowing a first exhaust gas at a first temperature within and along internal flow channels of a catalyst brick, and flowing a second exhaust gas at a second, different, temperature around an exterior of the catalyst brick. Heat may be transferred between the gases and the catalyst brick to achieve various operations.

Abstract: The invention relates to a vehicle drive train, especially for a truck or a rail vehicle, with a hydrodynamic retarder, which has a rotor and a stator or a rotor and a counter-rotating rotor, which together form a working chamber in which a circulating flow of a working medium can be established to hydrodynamically transfer torque from the rotor to the stator or to the counter-rotating rotor, or with a dynamic retarder, which has a rotor and a stator or a rotor and a counter-rotating rotor, in order to transfer torque from the rotor electrodynamically by means of magnetic force, or via liquid or mechanical friction, wherein the transfer of torque or a removal of heat from the retarder is accomplished using a working medium; with an expander that is operated with fluid or steam as the working medium and is used to supply mechanical drive power to the drive train.

Abstract: A system for energy conversion includes a first sub-system to be disposed at about a surface of the ocean and a second sub-system to be disposed at an ocean depth. The first sub-system includes an evaporation unit. The system also includes a turbine that is coupled between the first and second sub-systems. The first heat exchange unit is configured to vaporize a working fluid, the vaporized working fluid turns the turbine. The second sub-system is configured to condense the working fluid.

Abstract: A carbon-dioxide-capture-type steam power generation system 1 according to the present invention comprises a boiler 6 producing an exhaust gas 5 by combusting a fuel 2 and having a flue 8; an absorbing unit 40 being configured to absorb the carbon-dioxide contained in the exhaust gas 5 into an absorbing solution; and a regenerating unit 44 being configured to release the carbon dioxide gas from the absorbing solution absorbing the carbon dioxide and discharge the released carbon dioxide gas. Further, in this system, a reboiler 49 is provided for receiving a heating-medium as heat source, producing a steam 43 and supplying the produced steam 43 to the regenerating unit 44. Additionally, in the flue 8 of the boiler 6, a boiler-side heat exchanger 61 is provided for heating the heating-medium by the exhaust gas 5 passing therethrough.

Abstract: A low-pressure-vapor-recovery turbine generator that effectively recovers low-pressure steam emitted from a high-pressure-side steam turbine to generate electric power is provided. A low-pressure-vapor-recovery turbine that recovers low-pressure steam emitted from a high-pressure-side steam turbine and is rotationally driven, a generator that generates electric power with a rotational output of the low-pressure-vapor-recovery turbine, and a condenser that condenses into liquid exhaust steam from the low-pressure-vapor-recovery turbine are provided. The low-pressure-vapor-recovery turbine, generator, and condenser are installed in a portable outer casing that can be transported.

Abstract: An indirect-fired gas turbine power plant comprises a compressor; a turbine mechanically coupled to the compressor; a furnace; a heat exchanger inside the furnace and fluidly coupled at an inlet end to the compressor and at an outlet end to the turbine; and means for forming a gas barrier around a portion of the heat exchanger to impede combustion products from contacting the heat exchanger. Such means can be a plurality of gas discharge manifolds located around a portion of the heat exchanger. The manifolds can be coupled to heated working gas exhausted by the turbine.

Abstract: A combustion cap plate is disclosed. The combustion cap plate includes: a plate having a planar surface and configured to be affixed to an assembly connected to a turbine combustion chamber, the plate defining a central axis perpendicular to the planar surface; a plurality of openings through the plate; and a plurality of raised portions formed by the plate. The raised portions each extend away from the planar surface in a direction of the central axis and having a shape conforming to a thermal gradient incident on the plate during a combustion process.

Abstract: A gas turbine engine that includes a compressor, a combustion stage, a turbine assembly, a fuel gas feed system for supplying fuel gas to a combustion stage of the gas turbine, an integrated fuel gas characterization system, and a buffer tank is disclosed. The integrated fuel gas characterization system may determine the heating value of the fuel and adjust either the airflow to the compressor or the fuel gas flow to the combustor to maintain a design fuel-to-air ratio.

Abstract: A fuel injector tube includes a one piece, unitary, polygonal tube having an inlet end and an outlet end. The fuel injector tube further includes a fuel passage extending from the inlet end to the outlet end along a longitudinal axis of the polygonal tube, a plurality of air passages extending from the inlet end to the outlet end and surrounding the fuel passage, and a plurality of fuel holes. Each fuel hole connects an air passage with the fuel passage. The inlet end of the polygonal tube is formed into a fuel tube. A fuel injector includes a plurality of fuel injector tubes and a plate. The plurality of fuel tubes are connected to the plate adjacent the inlet ends of the plurality of fuel injector tubes.

Abstract: Gas turbine engine systems and methods involving enhanced fuel dispersion are provided. In this regard, a representative method for operating a gas turbine engine includes: providing a gas path through the engine; introducing a spray of fuel along the gas path downstream of a turbine of the engine; and impinging the spray of fuel with a relatively higher velocity flow of air such that atomization of the fuel is increased.

Abstract: A fuel injector head for a gas turbine engine the head comprising a pilot injector and a main injector located radially outwardly of the pilot injector. A concentric separates the pilot injector from the main injector and bounding a duct through which in use a fuel injected by the pilot injector flows. The splitter is hollow to improve cooling and has a radially inner surface which defines a first portion which tapers radially inwardly to a throat and a second portion which tapers radially outwardly from the throat with the angle of the radially outwards taper being such that a flow of air in use over the radially inner surface remains attached over the length of the surface.

Abstract: A fuel distribution manifold system for a gas turbine engine is disclosed that includes a plurality of interconnected manifold segments, each manifold segment extending between a pair of fittings, each manifold segment including at least one fuel transfer tube and a sealing tube that surrounds the at least one fuel transfer tube, wherein opposed end portions of the at least one fuel transfer tube are dynamically connected to the fittings and opposed end portions of the sealing tube are statically connected to the fittings.

Abstract: Systems and methods involving improved fuel atomization in air-blast fuel nozzles of gas turbine engines are provided. In this regard, a representative method includes: providing fuel to a chamber defined by an inner surface; and continuously atomizing a portion of the fuel via interaction of the fuel with the inner surface.

Abstract: A swirler is provided for a fuel injector of a combustor of a gas turbine engine. The swirler is for directing an airflow into the combustor so as to atomise fuel exiting the fuel injector. The swirler has one or more passages for channelling the airflow. Each of the passages is configured to rotate the airflow channelled by that passage about a swirl axis of the swirler, such that on exiting the passage the airflow has an exit swirl angle and a direction of rotation relative to the swirl axis. The swirler is configured such that the exit swirl angle and/or the direction of rotation may be selectively varied.

Abstract: An object of this invention is to accelerate further mixing of a fuel and air independently of a flow rate of the fuel. A gas turbine combustor comprises: a fuel nozzle for blowing out a gas fuel; an air nozzle plate with an air nozzle for jetting out the fuel and air into a combustion chamber after the blowout of the fuel from the fuel nozzle; and an obstacle formed inside the air nozzle; wherein the obstacle causes a collision of the fuel jet blown out from the fuel nozzle, and hence causes turbulence in an airflow streaming into the air nozzle. According to the invention, mixing between the fuel and the air can be further accelerated independently of the flow rate of the fuel.

Abstract: A combustor device and transition duct assembly is provided for use in a gas turbine engine. The combustor device comprises combustor structure having an exit portion; spring clips mounted to the exit portion of the combustor structure; and a burner assembly. The transition duct comprises a conduit having inlet and outlet sections and an abradable material layer provided along a circumferential portion of the inlet section of the transition duct conduit. The transition duct conduit inlet section may be coupled to the combustor structure exit portion such that the spring clips engage the abradable material layer.

Abstract: A gas turbine engine reverse-flow sheet metal combustor for an aero gas turbine engine has a louverless single-piece liner design which includes a plurality of effusion patches, containing multiple rows of effusion cooling holes, bounded by cooled effusionless bands to aid in repairability of the combustor. The cooling of the bands improves the durability of the combustor and provides a method of repair for the combustor.

Abstract: A turbine exhaust nozzle includes an inner shell disposed coaxially inside an outer shell to define a flow duct terminating in an outlet at a trailing edge of the outer shell. The inner shell is non-axisymmetric and varies in axial slope angle circumferentially around the duct.

Abstract: A method of controlling a fuel split of a pilot fuel flow and a main fuel flow in a gas turbine combustor during a load reduction is provided. The rate of change of fuel flow demand is monitored and an additional pilot fuel flow is added. The amount of additional pilot fuel flow depends on the rate of the change in fuel flow demand.

Abstract: A combustor system including a combustion chamber and at least one burner connected to the combustion chamber is provided. The combustion chamber includes a flow entrance which connects the burner to the combustion chamber, a flow exit through which combustion gases exit the combustion chamber, a chamber volume which extends between the flow entrance and the flow exit, and an inner chamber wall separating a cooling fluid channel from the chamber volume. A fuel supply line is present in the cooling fluid channel for supplying fuel to the cooling fluid. A method for reducing combustion instability and/or emissions of a combustor system is also provided.

Abstract: In a retrofit system for hot solids combustion and gasification, a chemical looping system includes an endothermic reducer reactor 12 having at least one materials inlet 22 for introducing carbonaceous fuel and CaCO3 therein and a CaS/gas outlet 26. A first CaS inlet 40 and a first CaSO4 inlet 64 are also defined by the reducer reactor 12. An oxidizer reactor 14 is provided and includes an air inlet 68, a CaSO4/gas outlet 46, a second CaS inlet 44, and a second CaSO4 inlet 66. A first separator 30 is in fluid communication with the CaS/gas outlet 26 and includes a product gas and a CaS/gas outlet 32 and 34 from which CaS is introduced into said first and second CaS inlets. A second separator 50 is in fluid communication with the CaSO4/gas outlet 46 and has an outlet 52 for discharging gas therefrom, and a CaSO4 outlet from which CaSO4 is introduced into the first and second CaSO4 inlets 62, 66.

Abstract: A device for the production and distribution of cold products, in particular for machines for the production of soft ice-cream, comprises a cylindrical chamber (12) equipped at one end with an inlet mouth (13) for a liquid food mixture and at an opposite end with an extraction tap (14) for the distribution of the cold food product, wherein said cylindrical chamber (12) is externally enveloped by an evaporation chamber (15) for the cooling of the liquid food mixture and contains in its interior a mixer (17).

Abstract: A multi-stage continuous liquid chilling system for chilling particulate food product with a chilling liquid. Particulate product is conveyed through a rotating drum as vanes inside the drum control and move the product from the inlet towards the outlet. As the product is conveyed it is tumbled and mixed with the chilling liquid in a succession of processing sections, each including a flood portion and a drain portion. In both sections the food product is exposed to a spray of chilled liquid, which Is drained off and used in an earlier stage in the processing cycle. While product is moved from the inlet to the outlet of the drum the chilling liquid is pumped in the opposite direction with a series of transfer pumps each connected to the drain sections in each chilling zone.

Abstract: The present invention relates to a refrigerator and/or freezer with a magnetic cooler, comprising a cold heat exchanger for cooling the cooling and/or freezing space of the appliance and means for detecting a value representative of the temperature of the cold heat exchanger, wherein the appliance includes a control or adjusting unit by means of which the temperature and/or the amount of the heat transfer medium supplied to the cold heat exchanger is adjustable such that in cooling operation the temperature of the cold heat exchanger does not go below 0° C.