EP4191061A1 - Cooling circuit - Google Patents

Abstract

A cooling circuit (100) is proposed. The cooling circuit comprises a refrigerant compressor (102) with a compressor drive (104) for driving the refrigerant compressor (102), a heat exchanger (106), in particular a condenser or gas cooler, with a fluid collection space (108), the fluid collection space (108) for forming a coolant supply formed of refrigerant, and a supply unit (114). The supply unit (114) has a pump (116). The supply unit (114) is connected to the fluid collection space (108) and the refrigerant compressor (102). The supply unit (114) is for selectively supplying refrigerant from the refrigerant store to at least one predetermined cooling point (118) of the refrigerant compressor (102) and/or the compressor drive (104) by means of the pump (116) at a predetermined pressure above a discharge pressure of the refrigerant compressor (102) trained. Furthermore, a method for operating a cooling circuit (100) is proposed.

Description

technical field

The present invention relates to a refrigeration circuit and a method for operating a refrigeration circuit.

Technical background

It is known from the prior art to use a refrigeration machine based on the compression refrigeration principle for cooling. The basic components of such a refrigeration machine are a compressor (also called a compressor), a heat exchanger such as a condenser (air or water-cooled), a throttle element (usually an expansion valve) and an evaporator. The compressor (or compressor) draws in the gaseous working substance, i.e. the refrigerant, from the evaporator. The refrigerant is brought to a higher pressure in the compressor. This gas heats up. Now this compressed gas enters the heat exchanger or condenser, where it is cooled under almost constant pressure. The refrigerant liquefies or cools down as a result of the heat extraction. The refrigerant then reaches the throttling element, where it is expanded to a lower pressure. When heat is supplied in the downstream evaporator, the refrigerant begins to boil, i.e. to evaporate. The environment cools down. This process runs continuously as long as the compressor is in operation. The refrigerant is not consumed because it is in a closed circuit.

From the WO 2015/071128 A1 is a cooling circuit comprising a refrigerant compressor with a suction connection and with a pressure chamber having a pressure connection, a condenser which is arranged in the cooling circuit following the pressure connection and has a fluid collection space in which a refrigerant supply is formed from refrigerant, an evaporator which is located in the cooling circuit between the condenser and the suction connection, and a supply unit which is connected on the one hand to the refrigerant supply and on the other hand to the pressure chamber for supplying Refrigerant from the refrigerant supply to the pressure chamber, which includes a pump unit for the refrigerant known. The pump unit has a housing that is closed in a pressure-tight manner and is only provided with an inlet and an outlet as accesses, in whose pump chamber a pump element that can be moved for pumping the refrigerant is arranged.

Despite the numerous advantages of the cooling circuits known from the prior art, these still contain potential for improvement.

According to the state of the art, semi-hermetic refrigerant compressors are mainly cooled with the cold suction gas from the refrigeration system. The suction gas first flows around the motor and then goes to the suction chamber. This causes pressure losses and a corresponding heating of the suction gas before it enters the working space. Both have a negative effect on the degree of delivery. Cooling by means of suction gas accordingly provokes a significant heating of the gas as well as an additional loss of pressure on the way into the working area. Both are disadvantageous both for the degree of delivery and for the energetic efficiency. The extent of the disadvantage depends on the structural design and the thermodynamic properties of the refrigerant. The amount and the temperature of the available suction gas depends heavily on the operating point of the refrigeration system. In some cases, extremely high temperature differences of up to 100 K occur between the suction gas and the electric motor around which the flow occurs.

Compressed gas cooling is sometimes also used in hermetic compressors. The gas, which is already very hot, flows around the electric motor after compression. From a thermodynamic point of view, this type of cooling can be rated as comparatively favorable, but the outlet temperatures from the working area - depending on the thermodynamic properties of the refrigerant - are up to temperatures of 100 °C to 180 °C. Cooling is therefore only possible to a limited extent. Active cooling of the compression process is not carried out with the refrigerant from the system. Another disadvantage is that When flowing through the crankcase, significant amounts of refrigeration machine oil can be discharged and carried into the system.

Water cooling is also sometimes used in process gas compressors or very large industrial refrigerant compressors. These are expensive and require additional components for the water circuit, including the same cooling. In addition, there must be a hermetic separation between the coolant and the refrigerant.

object of the invention

It would therefore be desirable to provide a cooling circuit and a method for operating a cooling circuit which at least largely avoid the disadvantages of known cooling circuits. In particular, the invention should enable needs-based and thermally homogeneous cooling of the working space and the compressor drive with one and the same working substance, i.e. refrigerant.

General Description of the Invention

This object is addressed by a refrigeration cycle and a method for operating a refrigeration cycle having the features of the independent claims. Advantageous developments, which can be implemented individually or in any combination, are presented in the dependent claims.

In the following, the terms "have", "have", "comprise" or "include" or any grammatical deviations thereof are used in a non-exclusive manner. Accordingly, these terms can refer both to situations in which, apart from the features introduced by these terms, no further features are present, or to situations in which one or more further features are present. For example, the expression "A has B", "A has B", "A comprises B" or "A includes B" can both refer to the situation in which, apart from B, there is no other element in A ( ie to a situation in which A consists exclusively of B), as well as to the situation in which, in addition to B, there are one or more other elements in A, e.g. element C, elements C and D or even further elements.

Furthermore, it is pointed out that the terms "at least one" and "one or more" as well as grammatical modifications of these terms are used when they are used in connection with one or more elements or features and are intended to express that the element or feature is provided once or several times can generally only be used once, for example when the feature or element is introduced for the first time. If the feature or element is subsequently mentioned again, the corresponding term "at least one" or "one or more" is generally no longer used, without restricting the possibility that the feature or element can be provided once or more than once.

Furthermore, the terms “preferably”, “in particular”, “for example” or similar terms are used below in connection with optional features, without alternative embodiments being restricted thereby. Thus, features introduced by these terms are optional features and are not intended to limit the scope of the claims, and in particular the independent claims, by these features. Thus, as will be appreciated by those skilled in the art, the invention may be practiced using other configurations. Similarly, features introduced by "in one embodiment of the invention" or by "in one embodiment of the invention" are understood to be optional features without intending to limit alternative configurations or the scope of the independent claims. Furthermore, through these introductory expressions, all possibilities to combine the features introduced here with other features, be they optional or non-optional features, remain untouched.

A cooling circuit is therefore proposed in a first aspect of the present invention. As used herein, the term "refrigeration cycle" is a broad term that should be given its ordinary and ordinary meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may, without Restriction, refer in particular to a system and preferably closed system, which uses a compressor to transport thermal energy from a colder location to be cooled to a warmer environment.The cooling circuit can be based on a thermodynamic cycle process.

The cooling circuit includes a refrigerant compressor with a compressor drive.

The term "refrigerant compressor" as used herein is a broad term which should be given its ordinary and ordinary meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may refer particularly, without limitation, to a machine (fluid energy machine) that performs mechanical work on a confined gas. Compressors are used to compress gases. They increase the pressure and density of the gas.

The term "compressor drive" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may refer specifically, without limitation, to a machine or device configured to drive the refrigerant compressor to perform the compression process. Such a driving machine is or includes a prime mover, which is also often referred to as a motor. Another technical means is often a gear inserted between the driven working machine in the form of the refrigerant compressor and the driving machine, which changes the movement and/or the force or the torque. Electric motors are preceded by at least one dynamo machine as an additional prime mover. This and the transmission lines are to be added to the extended drive. The energy required to provide the driving force may be basic electrical energy or combustion energy, the former being common in the technical field of the invention.

The cooling circuit also includes a heat exchanger with a fluid collection space. The fluid collection space is designed to form a refrigerant supply from refrigerant. The term "heat exchanger" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. In particular, the term may refer, without limitation, to an apparatus that transfers thermal energy from one stream of material to another.

The heat exchanger can be a condenser or gas cooler. The term "liquefier" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, refer in particular to an apparatus in which a substance is converted from the gaseous state of aggregation to the liquid state of aggregation by condensation. The term "liquefier" is used synonymously with the term "condenser". In refrigeration systems, condensers are used to condense the vaporous refrigerant. This enables a closed cycle process in refrigeration systems. The term "gas cooler" as used herein is a broad term which should be given its ordinary and ordinary meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. In particular, the term may refer, without limitation, to an apparatus that extracts heat from a gas and thus cools it. For example, in the case of supercritical operation, the refrigerant does not liquefy.

In the context of the present invention, the refrigerant is thus liquefied in the heat exchanger in subcritical operation, as is the case with the usual commercially used refrigerants (except carbon dioxide - CO ₂ ), but in supercritical operation the refrigerant is only cooled without this is liquefied.

The term "fluid plenum" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may refer particularly, without limitation, to a space where refrigerant is temporarily collected and stored. Thus, in the case of subcritical operation, liquid refrigerant collects in the fluid collection space, but in the case of supercritical operation, cooled, gaseous refrigerant collects. The fluid collection space can be a liquid separator. The purpose of a liquid separator is to continuously supply liquid refrigerant to the expansion device and to store excess refrigerant in the circuit.

The cooling circuit further includes a supply unit. The delivery unit has a pump. The supply unit is connected to the fluid collection space and the refrigerant compressor. The supply unit is for selectively supplying refrigerant from the refrigerant supply to at least one predetermined cooling point of the refrigerant compressor and/or the compressor drive by means of the pump at a predetermined pressure above a discharge pressure of the refrigerant compressor.

The term "cold spot" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, refer in particular to a place where cooling takes place or is intended to take place. Correspondingly, heat is dissipated at the cooling point by means of the refrigerant, which absorbs heat in the process.

The term "supply unit" as used herein is a broad term which should be given its ordinary and ordinary meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, relate in particular to a device that is set up to remove refrigerant from the fluid collection space and to convey it to the refrigerant compressor and/or the compressor drive, where the refrigerant is used to cool the refrigerant compressor and/or the compressor drive is used.

The term "optional supply" and its grammatical equivalents, as used herein, is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can be understood, without limitation, in particular as referring to a targeted or controlled supply to the refrigerant compressor and/or the compressor drive in such a way that the supply takes place in parallel or jointly or serially or individually. In other words, there is a fluid connection from the fluid collection space in principle both to the refrigerant compressor and to the compressor drive, the supply can be set so that it takes place both to the refrigerant compressor and to the compressor drive or exclusively to the refrigerant compressor or exclusively to the compressor drive .

The term "pump" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may refer particularly, without limitation, to a pump that has a generates high pressure, the pressure generated is in any case above the discharge pressure of the refrigerant compressor. The operating principle of the pump includes both mechanically and thermally driven pressure increases.

Correspondingly, in the cooling circuit according to the invention, selected areas are cooled in or on a refrigerant compressor and alternatively or additionally selected areas of the compressor drive with a targeted supply of cooling refrigerant. The refrigerant is supplied at a pressure above the high pressure in the refrigeration circuit. The necessary pressure is provided by a pump for liquid or supercritical refrigerant. First, refrigerant is taken from a reservoir on the high-pressure side in the liquid or supercritical state after the heat exchanger in the form of a condenser/gas cooler and compressed by a pump to a pressure level well above the high pressure. On the one hand, this pressure level must be selected in such a way that no evaporation occurs due to pressure losses within the downstream lines and components. On the other hand, a sufficient pressure level must be reached to enable the refrigerant to be returned to the heat exchanger or condenser after it has flowed through the selected areas of the refrigerant compressor and/or compressor drive. The cooling circuit is designed in such a way that it is possible to switch at any time between cooling the selected areas of the refrigerant compressor alone, the compressor drive alone or the refrigerant compressor and the compressor drive together. This configuration of the cooling circuit results in an increase in efficiency.

Furthermore, the cooling circuit according to the invention separates the main refrigerant flow for compression and the secondary refrigerant mass flow for cooling the compressor drive, such as a motor, and the compressor. For example, the cooling circuit allows the compression to be cooled by flowing around or through the liner and the valve plate and by spraying the refrigerant onto the underside of the piston crown. In addition, the cooling circuit allows the compressor drive, such as an electric motor and any electronics that may be present, to be cooled by spraying the refrigerant in a targeted manner at the cooling points.

The invention is thus based on the provision of a separate refrigerant mass flow for cooling the compressor at a pressure level above the high pressure inside of the refrigeration system, if necessary even in the supercritical state. The size of the separate refrigerant mass flow can be selected such that it is able to cool the compressor, in particular its drive, and also cool the compression process itself, such as the wall of the working space. Here, refrigerant for cooling is brought to the places where cooling is necessary. The high heat transfer coefficients of nucleate or flow boiling can be used, which favors heat transfer over a small area. The pressure change work for the cooling mass flow is realized exclusively by compressing liquid/supercritical fluid and is therefore particularly energy-efficient. A particularly efficient way of cooling the working space and the electric motor is achieved without interacting with the suction gas. This improves the volumetric efficiency and the energy efficiency of the refrigerant compressor. The components to be cooled are cooled more homogeneously and according to requirements. Minor leaks between the cooling mass flow and the main mass flow are irrelevant in terms of system operational safety.

The supply unit can be connected to the refrigerant compressor by means of at least one supply line and to the heat exchanger by means of at least one return line. The predetermined pressure can be selected in such a way that it at least compensates for pressure losses in the supply line and the return line. The pressure level should therefore be selected in such a way that the pressure loss within the downstream lines, throttles, ducts and the like is just overcome so that it can be returned to the condenser/gas cooler at the inlet.

The refrigerant compressor can be a reciprocating compressor with at least one working chamber and with at least one piston. The piston can be movably arranged in the working space. The working space can be delimited by at least one valve plate and one refrigerant compressor wall. The predetermined cooling point can include at least the refrigerant compressor wall, the valve plate of the refrigerant compressor and/or an underside of the piston. This allows parts of the refrigerant compressor to be cooled particularly efficiently as required.

The term "reciprocating compressor" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. In particular, the term may refer, without limitation, to a compressor in which the gas in a cylinder is drawn into the working space by a reciprocating piston, where it is compressed and then expelled again. These compressors work cyclically, have comparatively low volume flows and high pressure ratios. The suction and discharge valves are automatically working plate or lamella valves.

The term "workspace" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, refer in particular to a space of a compressor in which the compression of the gas takes place. The working space is located between the compressor housing and one or more displacers, such as pistons. From the point of view of the flow of the working material in a compressor, the working space is located between a suction chamber, into which the gas is first drawn in, and a pressure chamber, into which the compressed gas is fed before it is discharged from the compressor. For example, in a reciprocating compressor, gas in a cylinder is drawn into the suction chamber by a reciprocating piston, compressed in the working space, and the compressed gas is ejected from the pressure chamber.

The term "valve plate" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, refer in particular to a plate-shaped component that closes the working space of a compressor and in which valves are arranged for admitting a fluid medium originating from a suction chamber into and discharging the fluid medium from the working space into a pressure chamber. In the case of a reciprocating piston compressor, the valve plate is usually arranged on the side of the compressor housing which faces the top dead center of the piston.

The refrigerant compressor wall and/or the valve plate can have at least one refrigerant channel. In this case, the supply unit can be fluidly connected to the refrigerant channel. The refrigerant is thus preferably conducted in liquid form through one or more channels in the structure around the working space. The channels are to be inserted in such a way that the geometric arrangement is to be expected at a temperature within the working space above that of the refrigerant used for cooling. As it flows through, the refrigerant that is passed through absorbs heat and thus cools the walls of the working space. In particular, the high heat transfer coefficients in nucleate or flow boiling can be used. The flow through the valve plate is particularly advantageous. The flow channels should be selected in such a way that the heat transfer to the actual suction gas is kept as low as possible. The refrigerant mass flow through the individual channels should be selected in such a way that complete evaporation is achieved. The fully evaporated or heated refrigerant is fed back into the main mass flow before the condenser/gas cooler.

The supply unit may be configured to spray the refrigerant onto the underside of the bulb. This allows the piston to be cooled particularly efficiently during the compression process.

The supply unit may have at least a first injection nozzle for spraying the refrigerant onto the underside of the piston. As a result, the refrigerant is injected, which can preferably be done in such a way that the finely nebulized jet of refrigerant is applied to the underside of the piston in a well-distributed manner. This increases the surface area of the refrigerant available for heat transfer.

The compressor drive can have an electric motor with a stator and a rotor. The predetermined cooling point can include the stator, the rotor and/or a gap between the stator and the rotor. The coolant is brought to the electric motor and in particular the stator, rotor and air gap through suitable openings. The refrigerant absorbs heat. The heated refrigerant returns to the inlet side of the condenser/gas cooler via a recirculation system, possibly with oil separation.

The supply unit can be configured to spray the refrigerant onto the stator, the rotor and/or into the gap between the stator and the rotor. This allows the stator the rotor and/or the gap between the stator and the rotor are cooled particularly efficiently.

The supply unit can have at least one second injection nozzle for spraying the refrigerant onto the stator, the rotor, and/or into the gap between the stator and the rotor. As a result, the refrigerant is injected, which can preferably be done in such a way that the finely nebulized jet of refrigerant is distributed well onto the stator, the rotor and/or into the gap between the stator and the rotor. This increases the surface area of the refrigerant available for heat transfer.

The electric motor can be arranged in a sealed motor housing. As a result, no refrigerant gets into the environment, so that operational reliability is increased.

The electric motor can be connected to power electronics. The predetermined cooling point includes at least one component of the power electronics. In newer compressors, for example, power electronics are also attached to the motor. This can also be used in particular in the automotive air-conditioning sector, since compact construction is required there and cooling is difficult.

The term "power electronics" as used herein is a broad term that should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, relate in particular to components that are designed to convert electrical energy using switching electronic components. The conversion of electrical energy with converters, which are rotating machine sets consisting of an electric motor and generator, or power transformers are not counted as power electronics. Typical power electronics components are diac (to control thyristors), bipolar power transistor (switched-mode power supplies and DC/DC converters), power MOSFET (switched-mode power supplies and DC/DC converters), GTO thyristors (integrated gate-commutated thyristors, IGCT) (high power converters), IGBT (switching power supplies, motor controls, converters), thyristors (power converters, semiconductor relays, pulse current sources), triac (dimmers, semiconductor relays), diodes for rectification and as freewheeling diodes (Schottky diodes for low voltages up to about 200 V, silicon diodes for voltages up to a few kilovolts), and power capacitors.

Rectifiers are used to generate direct current from alternating current. They consist of several non-controlled diodes or actively controlled components such as thyristors or IGBTs, which when connected together become rectifiers. In power electronics, in particular, three-phase rectifiers such as the six-pulse circuit or the twelve-pulse circuit are used. Controlled power converters are rectifier circuits that work with thyristors, GTO thyristors or IGBT and allow the output voltage to be continuously adjusted. Here, a phase control shifts the switching on of the electronic switches by an adjustable angle within the period. They are often able to feed the current from the DC side back into the grid (four-quadrant operation). Inverters (also known as inverters) can convert direct current into alternating current. DC converters are used with DC power supply with step-up converters (step-up converters, boost converters) and step-down converters (buck controllers, step-down converters). The so-called "active PFC" (power factor correction) also works with a step-up converter connected downstream of the mains rectifier. These DC converters work with bipolar transistors, MOSFET or IGBT. Instead of diodes, synchronous rectifiers are often implemented in DC choppers, so that it is in principle also possible here to feed back current. AC power controllers are circuits with thyristors or triacs that are used to control the brightness of lamps (dimmers), the temperature of heating resistors or the control of magnetic coils or motors. Two thyristors connected in parallel in opposite directions or a triac also switch through both half-oscillations of the alternating current at a specific phase angle with phase control. Semiconductor relays are electronic AC voltage switches and also work with thyristors or triacs, they have built-in electrical isolation between the mains and signal circuits and switch either immediately or always at the zero crossing of the AC voltage in order to prevent interference emissions. Switching power supplies convert mains voltage into isolated, regulated direct voltages and work with a controlled inverter, which first generates a high-frequency alternating voltage from the rectified mains alternating voltage, which is then transformed and rectified. Switching power supplies work with bipolar transistors, MOSFET or IGBT.

The refrigeration cycle can further include an aftercooler for cooling the refrigerant from the refrigerant supply. The aftercooler increases the cooling capacity when cooling the compressor or its drive, since additional heat is extracted from the pressurized refrigerant. The aftercooler can be designed, for example, to cool the refrigerant from the refrigerant supply to a temperature that is essentially identical to an ambient temperature of the cooling circuit. The aftercooler can be arranged between the pump and the refrigerant compressor or the compressor drive.

The supply unit can be designed to supply essentially single-phase refrigerant from the refrigerant supply to the compressor and/or the compressor drive. Alternatively or additionally, the supply unit can be designed to supply refrigerant from the refrigerant supply to the predetermined cooling point of the refrigerant compressor and/or the compressor drive in a liquid or supercritical state. This enables very efficient cooling of the compression process. The cooling circuit is suitable for operation in the subcritical as well as in the supercritical range of the refrigerant.

The cooling circuit can also include a control unit. The control unit can be designed to control the timing of the supply of the refrigerant to the predetermined cooling point of the refrigerant compressor and/or the compressor drive. Correspondingly, the refrigerant can cool the refrigerant compressor and/or the compressor drive in a time-triggered manner by the control unit.

The term "controller" as used herein is a broad term which should be given its ordinary and current meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can refer in particular, without limitation, to a central part of a computer in which arithmetic operations take place and which controls other functions.

The control unit can be designed to control the supply of the refrigerant to the predetermined cooling point of the refrigerant compressor and/or the compressor drive based at least on a temperature of the refrigerant compressor and/or the compressor drive be. Accordingly, the cooling of the refrigerant compressor and/or the compressor drive can take place as required, such as when a temperature threshold value for the refrigerant compressor and/or the compressor drive is exceeded.

The timing can include a point in time and/or a length of the supply of the refrigerant to the predetermined cooling point of the refrigerant compressor and/or the compressor drive. Accordingly, the point in time at which the refrigerant is supplied to the predetermined cooling point of the refrigerant compressor and/or the compressor drive and/or the length of the supply and thus the amount of refrigerant supplied can be controlled in a targeted manner.

• Ansaugen eines Kältemittels mittels des Kältemittelverdichters,
• Verdichten des Kältemittels mittels des Kältemittelverdichters,
• Kühlen, insbesondere Rückkühlen und/oder Verflüssigen, des Kältemittels mittels des Wärmeübertragers,
• Zuführen des gekühlten Kältemittels zu dem Fluidsammelraum, und
• wahlweises Zuführen von Kältemittel aus dem Kältemittelvorrat zu mindestens einer vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs.

In a further aspect of the present invention, a method for operating a cooling circuit is proposed. The cooling circuit has a refrigerant compressor with a compressor drive for driving the refrigerant compressor, a heat exchanger, in particular a condenser or gas cooler, with a fluid collection space, the fluid collection space being designed to form a coolant supply from coolant, and a supply unit. The supply unit is connected to the fluid collection space and the refrigerant compressor. The method comprises the following steps, preferably in the order given:

• suction of a refrigerant by means of the refrigerant compressor,
• compressing the refrigerant using the refrigerant compressor,
• Cooling, in particular recooling and/or liquefaction, of the refrigerant by means of the heat exchanger,
• supplying the chilled refrigerant to the fluid plenum, and
• optional supply of refrigerant from the refrigerant supply to at least one predetermined cooling point of the refrigerant compressor and/or the compressor drive.

Correspondingly, in the method according to the invention, selected areas in or on a refrigerant compressor and alternatively or additionally selected areas of the compressor drive are cooled with a targeted supply of cooling refrigerant. The refrigerant is supplied at a pressure above the high pressure in the refrigeration cycle. The necessary pressure is provided by a pump for liquid or supercritical refrigerant. First, refrigerant on the high-pressure side is in the liquid or supercritical state after the heat exchanger in the form of a condenser/gas cooler from a reservoir and compressed by a pump to a pressure level well above the high pressure. On the one hand, this pressure level must be selected in such a way that no evaporation occurs due to pressure losses within the downstream lines and components. On the other hand, a sufficient pressure level must be reached to enable the refrigerant to be returned to the heat exchanger or condenser after it has flowed through the selected areas of the refrigerant compressor and/or compressor drive. The cooling circuit is designed in such a way that it is possible to switch at any time between cooling the selected areas of the refrigerant compressor alone, the compressor drive alone or the refrigerant compressor and the compressor drive together. This configuration of the cooling circuit results in an increase in efficiency.

Furthermore, the method according to the invention separates the main refrigerant flow for compression and the secondary refrigerant mass flow for cooling the compressor drive, such as a motor, and the compressor. For example, the cooling circuit allows the compression to be cooled by flowing around or through the liner and the valve plate and by spraying the refrigerant onto the underside of the piston head. In addition, the cooling circuit allows the compressor drive, such as an electric motor and any electronics that may be present, to be cooled by spraying the refrigerant in a targeted manner at the cooling points.

The invention is thus based on the provision of a separate refrigerant mass flow for cooling the compressor at a pressure level above the high pressure within the refrigeration system, if necessary even in the supercritical state. The size of the separate refrigerant mass flow can be selected such that it is able to cool the compressor, in particular its drive, and also cool the compression process itself, such as the wall of the working space. Here, refrigerant for cooling is brought to the places where cooling is necessary. The high heat transfer coefficients of nucleate or flow boiling can be used, which favors heat transfer over a small area. The pressure change work for the cooling mass flow is realized exclusively by compressing liquid/supercritical fluid and is therefore particularly energy-efficient. A particularly efficient way of cooling the working space and the electric motor is achieved without interacting with the suction gas. The degree of delivery and the energy efficiency of the Refrigerant compressor are thereby improved. The components to be cooled are cooled more homogeneously and according to requirements. Minor leaks between the cooling mass flow and the main mass flow are irrelevant in terms of system operational safety.

The refrigerant from the refrigerant supply can be supplied to the predetermined cooling points of the refrigerant compressor and/or the compressor drive at a predetermined pressure above a discharge pressure of the refrigerant compressor.

The supply unit can be connected to the refrigerant compressor by means of at least one supply line and to the heat exchanger by means of at least one return line. The predetermined pressure can be selected in such a way that it at least compensates for pressure losses in the supply line and the return line. The pressure level should therefore be selected in such a way that the pressure loss within the downstream lines, throttles, ducts and the like is just overcome so that it can be returned to the condenser/gas cooler at the inlet.

The refrigerant compressor can be a reciprocating compressor with at least one working chamber and with at least one piston. The piston can be movably arranged in the working space. The working space can be delimited by at least one valve plate and one refrigerant compressor wall. The predetermined cooling point can include at least the refrigerant compressor wall, the valve plate of the refrigerant compressor and/or an underside of the piston. This allows parts of the refrigerant compressor to be cooled particularly efficiently as required.

The refrigerant compressor wall and/or the valve plate can have at least one refrigerant channel. In this case, the supply unit can be fluidly connected to the refrigerant channel. The refrigerant can be supplied to the refrigerant channel. The refrigerant is thus preferably conducted in liquid form through one or more channels in the structure around the working space. The ducts are to be introduced in such a way that the geometrical arrangement is to be expected at a temperature within the working space above that of the refrigerant used for cooling. As it flows through, the refrigerant that is passed through absorbs heat and thus cools the walls of the working space. In particular, the high heat transfer coefficients in nucleate or flow boiling can be used. The flow through the valve plate is particularly advantageous. The flow channels should be selected in such a way that the heat transfer to the actual suction gas is kept as low as possible. The refrigerant mass flow through the individual channels should be selected in such a way that complete evaporation is achieved. The fully evaporated or heated refrigerant is fed back into the main mass flow before the condenser/gas cooler.

The refrigerant can be sprayed on the bottom of the bulb. This allows the piston to be cooled particularly efficiently during the compression process.

The refrigerant may be sprayed onto the underside of the piston using a first injection nozzle. As a result, the refrigerant is injected, which can preferably be done in such a way that the finely nebulized jet of refrigerant is applied to the underside of the piston in a well-distributed manner. This increases the surface area of the refrigerant available for heat transfer.

The compressor drive can have an electric motor with a stator and a rotor. The predetermined cooling point can include the stator, the rotor and/or a gap between the stator and the rotor. The coolant is brought to the electric motor and in particular the stator, rotor and air gap through suitable openings. The refrigerant absorbs heat. The heated refrigerant returns to the inlet side of the condenser/gas cooler via a recirculation system, possibly with oil separation.

The refrigerant can be sprayed onto the stator, the rotor, and/or into the gap between the stator and the rotor. The stator, the rotor and/or the gap between the stator and the rotor can thus be cooled particularly efficiently.

The refrigerant can be sprayed onto the stator, the rotor, and/or into the gap between the stator and the rotor by means of a second injection nozzle. As a result, the refrigerant is injected, which can preferably be done in such a way that the finely nebulized jet of refrigerant is distributed well onto the stator, the rotor and/or into the gap between the stator and the rotor. This increases the surface area of the refrigerant available for heat transfer.

The electric motor can be placed in a sealed motor housing. As a result, no refrigerant gets into the environment, so that operational reliability is increased.

The electric motor can be connected to power electronics. The predetermined cooling point includes at least one component of the power electronics.

The method may further include cooling the refrigerant from the refrigerant supply using an aftercooler. The aftercooler increases the cooling capacity when cooling the compressor or its drive, since additional heat is extracted from the pressurized refrigerant. The post-cooling can be carried out, for example, to cool the refrigerant from the refrigerant supply to a temperature that is essentially identical to an ambient temperature of the cooling circuit. After-cooling can take place between the pump and the refrigerant compressor or the compressor drive.

The refrigerant may be delivered from the refrigerant supply to the compressor and/or compressor drive in a substantially single phase state and/or in a liquid or supercritical state. This enables very efficient cooling of the compression process. The cooling circuit is suitable for operation in the subcritical as well as in the supercritical range of the refrigerant.

The method may further include timing the delivery of the refrigerant to the predetermined refrigeration location of the refrigerant compressor and/or the compressor drive. Correspondingly, the refrigerant can cool the refrigerant compressor and/or the compressor drive in a time-triggered manner.

The delivery of the refrigerant to the predetermined cooling point of the refrigerant compressor and/or the compressor drive can be timed based at least on a temperature of the refrigerant compressor and/or the compressor drive. Accordingly, the cooling of the refrigerant compressor and/or the compressor drive can take place as required, such as when a temperature threshold value for the refrigerant compressor and/or the compressor drive is exceeded.

The timing can include a point in time and/or a length of the supply of the refrigerant to the predetermined cooling point of the refrigerant compressor and/or the compressor drive. Include refrigerant compressor and / or compressor drive. Accordingly, the point in time at which the refrigerant is supplied to the predetermined cooling point of the refrigerant compressor and/or the compressor drive and/or the length of the supply and thus the amount of refrigerant supplied can be controlled in a targeted manner.

Furthermore, within the scope of the present invention, a computer program is proposed which, when run on a computer or computer network, executes the method according to the invention in one of its configurations.

Furthermore, within the scope of the present invention, a computer program with program code means is proposed in order to carry out the method according to the invention in one of its configurations when the program is run on a computer or computer network. In particular, the program code means can be stored on a computer-readable data carrier and/or a computer-readable storage medium.

In particular, the terms "computer-readable data carrier" and "computer-readable storage medium" as used herein may refer to non-transitory data storage, for example a hardware data storage medium on which computer-executable instructions are stored. The computer-readable data carrier or the computer-readable storage medium can in particular be or include a storage medium such as a random access memory (RAM) and/or a read-only memory (ROM).

In addition, the present invention proposes a data carrier on which a data structure is stored which, after loading into a working memory and/or main memory of a computer or computer network, can execute the method according to the invention in one of its configurations.

A computer program product with program code means stored on a machine-readable carrier is also proposed within the scope of the present invention in order to carry out the method according to the invention in one of its configurations when the program is executed on a computer or computer network.

A computer program product is understood as the program as a tradable product. In principle, it can be in any form, for example on paper or on a computer-readable data medium, and can be distributed in particular via a data transmission network.

Finally, within the scope of the present invention, a modulated data signal is proposed, which contains instructions that can be executed by a computer system or computer network for executing a method according to one of the described embodiments.

With regard to the computer-implemented aspects of the invention, one, several or even all method steps of the method according to one or more of the configurations proposed here can be carried out by means of a computer or computer network. Thus, in general, any of the method steps including the provision and/or manipulation of data can be performed using a computer or computer network. In general, these steps may include any of the method steps excluding steps that require manual labor, such as providing samples and/or certain aspects of making actual measurements.

• Ausführungsform 1: Kühlkreislauf umfassend
  • einen Kältemittelverdichter mit einem Verdichterantrieb zum Antreiben des Kältemittelverdichters,
  • einen Wärmeübertrager insbesondere ein Verflüssiger oder Gaskühler, mit einem Fluidsammelraum, wobei der Fluidsammelraum zum Bilden eines Kältemittelvorrats aus Kältemittel ausgebildet ist, und
  • eine Zufuhreinheit, wobei die Zufuhreinheit eine Pumpe aufweist, wobei die Zufuhreinheit mit dem Fluidsammelraum und dem Kältemittelverdichter verbunden ist, wobei die Zufuhreinheit zum wahlweisen Zuführen von Kältemittel aus dem Kältemittelvorrat zu mindestens einer vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs mittels der Pumpe bei einem vorbestimmten Druck oberhalb eines Abgabedrucks des Kältemittelverdichters ausgebildet ist.
• Ausführungsform 2: Kühlkreislauf nach der vorhergehenden Ausführungsform, wobei die Zufuhreinheit mittels mindestens einer Zufuhrleitung mit dem Kältemittelverdichter und mittels mindestens einer Rückführungsleitung mit dem Wärmeübertrager verbunden ist, wobei der vorbestimmte Druck so gewählt ist, dass er mindestens Druckverluste in der Zufuhrleitung und der Rückführungsleitung kompensiert.
• Ausführungsform 3: Kühlkreislauf nach einer der vorhergehenden Ausführungsformen, wobei der Kältemittelverdichter ein Hubkolbenverdichter mit mindestens einem Arbeitsraum und mit mindestens einem Kolben ist, wobei der Kolben beweglich in dem Arbeitsraum angeordnet ist, wobei der Arbeitsraum von mindestens einer Ventilplatte und einer Kältemittelverdichterwand begrenzt ist, wobei die vorbestimmte Kühlstelle mindestens die Kältemittelverdichterwand, die Ventilplatte des Kältemittelverdichters und/oder eine Unterseite des Kolbens umfasst.
• Ausführungsform 4: Kühlkreislauf nach der vorhergehenden Ausführungsform, wobei die Kältemittelverdichterwand und/oder die Ventilplatte mindestens einen Kältemittelkanal aufweist, wobei die Zufuhreinheit mit dem Kältemittelkanal fluidverbunden ist.
• Ausführungsform 5: Kühlkreislauf nach einer der beiden vorhergehenden Ausführungsformen, wobei die Zufuhreinheit zum Sprühen des Kältemittels auf die Unterseite des Kolbens ausgebildet ist.
• Ausführungsform 6: Kühlkreislauf nach der vorhergehenden Ausführungsform, wobei die Zufuhreinheit mindestens eine erste Einspritzdüse zum Sprühen des Kältemittels auf die Unterseite des Kolbens aufweist.
• Ausführungsform 7: Kühlkreislauf nach einer der vorhergehenden Ausführungsformen, wobei der Verdichterantrieb einen Elektromotor mit einem Stator und einem Rotor aufweist, wobei die vorbestimmte Kühlstelle den Stator, den Rotor, und/oder einen Spalt zwischen dem Stator und dem Rotor umfasst.
• Ausführungsform 8: Kühlkreislauf nach der vorhergehenden Ausführungsform, wobei die Zufuhreinheit zum Sprühen des Kältemittels auf den Stator, den Rotor, und/oder in den Spalt zwischen dem Stator und dem Rotor ausgebildet ist.
• Ausführungsform 9: Kühlkreislauf nach der vorhergehenden Ausführungsform, wobei die Zufuhreinheit mindestens eine zweite Einspritzdüse zum Sprühen des Kältemittels auf den Stator, den Rotor, und/oder in den Spalt zwischen dem Stator und dem Rotor aufweist.
• Ausführungsform 10: Kühlkreislauf nach einer der drei vorhergehenden Ausführungsformen, wobei der Elektromotor in einem abgedichteten Motorgehäuse angeordnet ist.
• Ausführungsform 11: Kühlkreislauf nach einer der vier vorhergehenden Ausführungsformen, wobei der Elektromotor mit einer Leistungselektronik verbunden ist, wobei die vorbestimmte Kühlstelle mindestens ein Bauteil der Leistungselektronik umfasst.
• Ausführungsform 12: Kühlkreislauf nach einer der vorhergehenden Ausführungsformen, weiterhin umfassend einen Nachkühler zum Kühlen des Kältemittels aus dem Kältemittelvorrat, insbesondere zum Kühlen auf eine Temperatur, die im Wesentlichen identisch zu einer Umgebungstemperatur des Kühlkreislaufs ist.
• Ausführungsform 13: Kühlkreislauf nach einer der vorhergehenden Ausführungsformen, wobei die Zufuhreinheit zum Zuführen von im Wesentlichen einphasigen Kältemittel aus dem Kältemittelvorrat zu dem Verdichter und/oder Verdichterantrieb ausgebildet ist und/oder wobei die Zufuhreinheit zum Zuführen von Kältemittel aus dem Kältemittelvorrat zu der vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs in einem flüssigen oder überkritischen Zustand ausgebildet ist.
• Ausführungsform 14: Kühlkreislauf nach einer der vorhergehenden Ausführungsformen, weiterhin umfassend eine Steuereinheit, wobei die Steuereinheit zum zeitlichen Steuern der Zufuhr des Kältemittels zu der vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs ausgebildet ist.
• Ausführungsform 15: Kühlkreislauf nach der vorhergehenden Ausführungsform, wobei die Steuereinheit ausgebildet ist zum Steuern der Zufuhr des Kältemittels zu der vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs zumindest basierend auf einer Temperatur des Kältemittelverdichters und/oder des Verdichterantriebs.
• Ausführungsform 16: Kühlkreislauf nach einer der beiden vorhergehenden Ausführungsformen, wobei das zeitliche Steuern einen Zeitpunkt und/oder eine Länge der Zufuhr des Kältemittels zu der vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs umfasst.
• Ausführungsform 17: Verfahren zum Betreiben eines Kühlkreislaufs, wobei der Kühlkreislauf einen Kältemittelverdichter mit einem Verdichterantrieb zum Antreiben des Kältemittelverdichters, einen Wärmeübertrager insbesondere ein Verflüssiger oder Gaskühler, mit einem Fluidsammelraum, wobei der Fluidsammelraum zum Bilden eines Kältemittelvorrats aus Kältemittel ausgebildet ist, und eine Zufuhreinheit, wobei die Zufuhreinheit mit dem Fluidsammelraum und dem Kältemittelverdichter verbunden ist, wobei das Verfahren umfasst:
  • Ansaugen eines Kältemittels mittels des Kältemittelverdichters,
  • Verdichten des Kältemittels mittels des Kältemittelverdichters,
  • Kühlen, insbesondere Rückkühlen und/oder Verflüssigen, des Kältemittels mittels des Wärmeübertragers,
  • Zuführen des gekühlten Kältemittels zu dem Fluidsammelraum, und
  • wahlweises Zuführen von Kältemittel aus dem Kältemittelvorrat zu mindestens einer vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs bei einem vorbestimmten Druck oberhalb eines Abgabedrucks des Kältemittelverdichters.
• Ausführungsform 18: Verfahren nach der vorhergehenden Ausführungsform, wobei die Zufuhreinheit mittels mindestens einer Zufuhrleitung mit dem Kältemittelverdichter und mittels mindestens einer Rückführungsleitung mit dem Wärmeübertrager verbunden ist, wobei der vorbestimmte Druck so gewählt wird, dass er mindestens Druckverluste in der Zufuhrleitung und der Rückführungsleitung kompensiert.
• Ausführungsform 19: Verfahren nach einem der Ausführungsformen 17 bis 19, wobei der Kältemittelverdichter ein Hubkolbenverdichter mit mindestens einem Arbeitsraum und mit mindestens einem Kolben ist, wobei der Kolben beweglich in dem Arbeitsraum angeordnet ist, wobei der Arbeitsraum von mindestens einer Ventilplatte und einer Kältemittelverdichterwand begrenzt ist, wobei die vorbestimmte Kühlstelle mindestens die Kältemittelverdichterwand, die Ventilplatte des Kältemittelverdichters und/oder eine Unterseite des Kolbens umfasst.
• Ausführungsform 20: Verfahren nach der vorhergehenden Ausführungsform, wobei die Kältemittelverdichterwand und/oder die Ventilplatte mindestens einen Kältemittelkanal aufweist, wobei die Zufuhreinheit mit dem Kältemittelkanal fluidverbunden wird, wobei das Kältemittel dem Kältemittelkanal zugeführt wird.
• Ausführungsform 21: Verfahren nach einer der beiden vorhergehenden Ausführungsformen, wobei das Kältemittel auf die Unterseite des Kolbens gesprüht wird.
• Ausführungsform 22: Verfahren nach der vorhergehenden Ausführungsform, wobei das Kältemittel auf die Unterseite des Kolbens mittels einer ersten Einspritzdüse gesprüht wird.
• Ausführungsform 23: Verfahren nach einem der Ausführungsformen 17 bis 23, wobei der Verdichterantrieb einen Elektromotor mit einem Stator und einem Rotor aufweist, wobei die vorbestimmte Kühlstelle den Stator, den Rotor, und/oder einen Spalt zwischen dem Stator und dem Rotor umfasst.
• Ausführungsform 24: Verfahren nach der vorhergehenden Ausführungsform, wobei das Kältemittel auf den Stator, den Rotor, und/oder in den Spalt zwischen dem Stator und dem Rotor gesprüht wird.
• Ausführungsform 25: Verfahren nach der vorhergehenden Ausführungsform, wobei das Kältemittel auf den Stator, den Rotor, und/oder in den Spalt zwischen dem Stator und dem Rotor mittels einer zweiten Einspritzdüse gesprüht wird.
• Ausführungsform 26: Verfahren nach einer der drei vorhergehenden Ausführungsformen, wobei der Elektromotor in einem abgedichteten Motorgehäuse angeordnet wird.
• Ausführungsform 27: Verfahren nach einer der vier vorhergehenden Ausführungsformen, wobei der Elektromotor mit einer Leistungselektronik verbunden wird, wobei die vorbestimmte Kühlstelle mindestens ein Bauteil der Leistungselektronik umfasst.
• Ausführungsform 28: Verfahren nach einem der Ausführungsformen 17 bis 27, weiterhin umfassend Kühlen des Kältemittels aus dem Kältemittelvorrat, insbesondere Kühlen auf eine Temperatur, die im Wesentlichen identisch zu einer Umgebungstemperatur des Kühlkreislaufs ist, mittels eines Nachkühlers.
• Ausführungsform 29: Verfahren nach einem der Ausführungsformen 17 bis 28, wobei das Kältemittel im Wesentlichen in einem einphasigen Zustand aus dem Kältemittelvorrat zu dem Verdichter und/oder Verdichterantrieb und/oder in einem flüssigen oder überkritischen Zustand zugeführt wird.
• Ausführungsform 30: Verfahren nach einem der Ausführungsformen 17 bis 29, weiterhin umfassend zeitliches Steuern der Zufuhr des Kältemittels zu der vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs.
• Ausführungsform 31: Verfahren nach der vorhergehenden Ausführungsform, wobei die Zufuhr des Kältemittels zu der vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs zumindest basierend auf einer Temperatur des Kältemittelverdichters und/oder des Verdichterantriebs zeitlich gesteuert wird.
• Ausführungsform 32: Verfahren nach einer der beiden vorhergehenden Ausführungsformen, wobei das zeitliche Steuern einen Zeitpunkt und/oder eine Länge der Zufuhr des Kältemittels zu der vorbestimmten Kühlstelle des Kältemittelverdichters und/oder des Verdichterantriebs umfasst.

In summary, the following embodiments are proposed without restricting further possible configurations:

• Embodiment 1: refrigeration cycle comprising
  • a refrigerant compressor with a compressor drive for driving the refrigerant compressor,
  • a heat exchanger, in particular a condenser or gas cooler, with a fluid collection space, the fluid collection space being designed to form a coolant supply from coolant, and
  • a supply unit, the supply unit having a pump, the supply unit being connected to the fluid collection space and the refrigerant compressor, the supply unit for selectively supplying refrigerant from the refrigerant supply to at least one predetermined cooling point of the refrigerant compressor and/or the compressor drive by means of the pump at one predetermined pressure is formed above a discharge pressure of the refrigerant compressor.
• Embodiment 2: Cooling circuit according to the previous embodiment, wherein the supply unit is connected to the refrigerant compressor by means of at least one supply line and to the heat exchanger by means of at least one return line, the predetermined pressure being selected such that it at least compensates for pressure losses in the supply line and the return line.
• Embodiment 3: Cooling circuit according to one of the preceding embodiments, wherein the refrigerant compressor is a reciprocating piston compressor with at least one working chamber and with at least one piston, the piston being movably arranged in the working chamber, the working chamber being delimited by at least one valve plate and a refrigerant compressor wall, wherein the predetermined cooling point comprises at least the refrigerant compressor wall, the valve plate of the refrigerant compressor and/or an underside of the piston.
• Embodiment 4: Cooling circuit according to the previous embodiment, wherein the refrigerant compressor wall and/or the valve plate has at least one refrigerant channel, wherein the supply unit is fluidly connected to the refrigerant channel.
• Embodiment 5: Refrigeration cycle according to one of the two previous embodiments, wherein the supply unit is designed for spraying the refrigerant onto the underside of the piston.
• Embodiment 6: The refrigeration cycle according to the preceding embodiment, wherein the supply unit has at least a first injection nozzle for spraying the refrigerant onto the bottom of the piston.
• Embodiment 7: Cooling circuit according to one of the preceding embodiments, wherein the compressor drive has an electric motor with a stator and a rotor, the predetermined cooling point comprising the stator, the rotor and/or a gap between the stator and the rotor.
• Embodiment 8: The refrigeration cycle according to the foregoing embodiment, wherein the supply unit is configured to spray the refrigerant onto the stator, the rotor, and/or into the gap between the stator and the rotor.
• Embodiment 9: The refrigeration cycle according to the previous embodiment, wherein the supply unit has at least one second injection nozzle for spraying the refrigerant onto the stator, the rotor, and/or into the gap between the stator and the rotor.
• Embodiment 10: Cooling circuit according to one of the three previous embodiments, wherein the electric motor is arranged in a sealed motor housing.
• Embodiment 11: Cooling circuit according to one of the four preceding embodiments, wherein the electric motor is connected to power electronics, wherein the predetermined cooling point comprises at least one component of the power electronics.
• Embodiment 12: Cooling circuit according to one of the preceding embodiments, further comprising an aftercooler for cooling the refrigerant from the coolant supply, in particular for cooling to a temperature which is essentially identical to an ambient temperature of the cooling circuit.
• Embodiment 13: Cooling circuit according to one of the preceding embodiments, wherein the supply unit is designed to supply essentially single-phase refrigerant from the refrigerant supply to the compressor and/or compressor drive and/or wherein the supply unit is designed to supply refrigerant from the refrigerant supply to the predetermined cooling point of the Refrigerant compressor and / or the compressor drive is formed in a liquid or supercritical state.
• Embodiment 14: Cooling circuit according to one of the preceding embodiments, further comprising a control unit, wherein the control unit is designed for timing the supply of the refrigerant to the predetermined cooling point of the refrigerant compressor and/or the compressor drive.
• Embodiment 15: cooling circuit according to the previous embodiment, wherein the control unit is designed to control the supply of refrigerant to the predetermined cooling point of the refrigerant compressor and/or the compressor drive at least based on a temperature of the refrigerant compressor and/or the compressor drive.
• Embodiment 16: Cooling circuit according to one of the two preceding embodiments, wherein the time control comprises a point in time and/or a length of the supply of the refrigerant to the predetermined cooling point of the refrigerant compressor and/or the compressor drive.
• Embodiment 17: Method for operating a refrigeration circuit, the refrigeration circuit having a refrigerant compressor with a compressor drive for driving the refrigerant compressor, a heat exchanger, in particular a condenser or gas cooler, with a fluid collection space, the fluid collection space being designed to form a refrigerant supply from refrigerant, and a supply unit, wherein the supply unit is connected to the fluid collection space and the refrigerant compressor, the method comprising:
  • suction of a refrigerant by means of the refrigerant compressor,
  • compressing the refrigerant using the refrigerant compressor,
  • Cooling, in particular recooling and/or liquefaction, of the refrigerant by means of the heat exchanger,
  • supplying the chilled refrigerant to the fluid plenum, and
  • selectively supplying refrigerant from the refrigerant supply to at least one predetermined cooling point of the refrigerant compressor and/or the compressor drive at a predetermined pressure above a discharge pressure of the refrigerant compressor.
• Embodiment 18: Method according to the previous embodiment, wherein the supply unit is connected to the refrigerant compressor by means of at least one supply line and to the heat exchanger by means of at least one return line, the predetermined pressure being selected such that it at least compensates for pressure losses in the supply line and the return line.
• Embodiment 19 Method according to one of embodiments 17 to 19, wherein the refrigerant compressor is a reciprocating piston compressor with at least one working chamber and with at least one piston, the piston being movably arranged in the working chamber, the working chamber being delimited by at least one valve plate and one refrigerant compressor wall , wherein the predetermined cooling point comprises at least one of the refrigerant compressor wall, the valve plate of the refrigerant compressor and an underside of the piston.
• Embodiment 20: Method according to the previous embodiment, wherein the refrigerant compressor wall and/or the valve plate has at least one refrigerant channel, wherein the supply unit is fluidly connected to the refrigerant channel, wherein the refrigerant is supplied to the refrigerant channel.
• Embodiment 21 Method according to either of the two preceding embodiments, wherein the refrigerant is sprayed onto the underside of the bulb.
• Embodiment 22: Method according to the previous embodiment, wherein the refrigerant is sprayed onto the underside of the piston by means of a first injection nozzle.
• Embodiment 23: The method according to any one of embodiments 17 to 23, wherein the compressor drive comprises an electric motor with a stator and a rotor, wherein the predetermined cooling point comprises the stator, the rotor, and/or a gap between the stator and the rotor.
• Embodiment 24: Method according to the previous embodiment, wherein the refrigerant is sprayed onto the stator, the rotor, and/or into the gap between the stator and the rotor.
• Embodiment 25: Method according to the previous embodiment, wherein the refrigerant is sprayed onto the stator, the rotor, and/or into the gap between the stator and the rotor by means of a second injection nozzle.
• Embodiment 26 Method according to one of the three previous embodiments, wherein the electric motor is arranged in a sealed motor housing.
• Embodiment 27 Method according to one of the four preceding embodiments, wherein the electric motor is connected to power electronics, wherein the predetermined cooling point comprises at least one component of the power electronics.
• Embodiment 28 Method according to one of embodiments 17 to 27, further comprising cooling the refrigerant from the refrigerant store, in particular cooling to a temperature which is essentially identical to an ambient temperature of the cooling circuit, by means of an aftercooler.
• Embodiment 29: The method of any one of embodiments 17-28, wherein the refrigerant is delivered from the refrigerant supply to the compressor and/or compressor drive in a substantially single phase state and/or in a liquid or supercritical state.
• Embodiment 30: The method according to any one of embodiments 17 to 29, further comprising timing the delivery of the refrigerant to the predetermined cooling location of the refrigerant compressor and/or the compressor drive.
• Embodiment 31: The method of the preceding embodiment, wherein delivery of the refrigerant to the predetermined cold location of the refrigerant compressor and/or the compressor drive is timed based at least on a temperature of the refrigerant compressor and/or the compressor drive.
• Embodiment 32 Method according to one of the two preceding embodiments, wherein the timing control comprises a point in time and/or a length of the supply of the refrigerant to the predetermined cooling point of the refrigerant compressor and/or the compressor drive.

Brief description of the figures

Further details and features emerge from the following description of exemplary embodiments, in particular in connection with the dependent claims. The respective features can be implemented individually or in combination with one another. The invention is not limited to the exemplary embodiments. The exemplary embodiments are shown schematically in the figures. The same reference numerals in the individual figures designate elements that are the same or have the same function or that correspond to one another in terms of their functions.

Figur 1

ein schematisches Schaltbild eines erfindungsgemäßen Kühlkreislaufs;

Figur 2

eine schematische Darstellung einer möglichen Kühlstelle;

Figur 3

eine schematische Darstellung einer weiteren möglichen Kühlstelle;

Figur 4

eine schematische Darstellung einer weiteren möglichen Kühlstelle;

Figur 5

eine schematische Darstellung einer weiteren möglichen Kühlstelle; und

Figur 6

eine schematische Darstellung einer weiteren möglichen Kühlstelle.

Show in detail:

figure 1

a schematic circuit diagram of a cooling circuit according to the invention;

figure 2

a schematic representation of a possible cooling point;

figure 3

a schematic representation of another possible cooling point;

figure 4

a schematic representation of another possible cooling point;

figure 5

a schematic representation of another possible cooling point; and

figure 6

a schematic representation of another possible cooling point.

Description of the exemplary embodiments

figure 1 shows a schematic circuit diagram of a cooling circuit 100 according to the invention. The cooling circuit 100 comprises a refrigerant compressor 102 with a compressor drive 104. The cooling circuit 100 further comprises a heat exchanger 106. The heat exchanger 106 is connected to a pressure chamber of the refrigerant compressor 102, which is not shown in detail and has a pressure connection. Depending on the refrigerant used, the heat exchanger 106 is a condenser or gas cooler. For example, the heat exchanger 106 is designed as a condenser in the case of NH ₃ as the refrigerant and as a gas cooler in the case of CO ₂ as the refrigerant. The heat exchanger 106 has a fluid collection space 108 . The fluid collection space 108 is designed to form a refrigerant reservoir of refrigerant. The fluid collection space 108 is a collector or liquid separator depending on the refrigerant used.

In order to implement a closed cooling circuit 100, the cooling circuit 100 also has an expansion element 110 connected to the heat exchanger 106 or the fluid collection space 108 and an evaporator 112, which is connected to the expansion element 110 and to a suction chamber of the refrigerant compressor 102, which is not shown in detail and has a suction connection connected is.

The cooling circuit 100 also includes a supply unit 114. The supply unit 114 is connected to the fluid collection space 108 and the refrigerant compressor 102 and the compressor drive 104. The supply unit 114 has a pump 116 . Supply unit 114 is designed to selectively supply refrigerant from the refrigerant supply of fluid collection chamber 108 to at least one predetermined cooling point 118 of refrigerant compressor 102 and/or compressor drive 104 at a pressure above a discharge pressure of refrigerant compressor 102 by means of pump 116. The predetermined cooling point 118 is shown here as an example of an expansion point. Thus, the supply unit 114 is connected both to the fluid collection space 108 and to the refrigerant compressor 102 by means of at least one supply line 120 and to the heat exchanger 106 by means of at least one return line 122 . For example, the return line 122 extends from the refrigerant compressor 102 and opens into a refrigerant line 124 which connects the pressure chamber of the refrigerant compressor 102 and the heat exchanger 106 to one another. The predetermined pressure is selected in such a way that it at least compensates for pressure losses in the supply line 120 and the return line 122 .

The pump 116 can be driven by its own drive. Alternatively, the pump can be driven directly by the refrigerant compressor 102 . For example, the pump 116 can either be connected to the refrigerant compressor 102 by means of a small gearbox or can be arranged or seated directly on the shaft of the refrigerant compressor 102 . This optional embodiment has the advantage that a liquid line is laid back to the refrigerant compressor 102 which is at the pressure of the fluid collection space 108 (condensing pressure). In this context, the geodetic arrangement of the pump 116 at a level below the fluid collection chamber is particularly advantageous. As a result, the pressure in front of or upstream of the pump 116 is immediately increased by the hydrostatic pressure and cavitation is further avoided or prevented.

In particular, the supply unit 114 for supplying essentially single-phase refrigerant from the refrigerant supply to the predetermined cooling point 118 by means of Pump 116 formed. Thus, the supply unit 114 is also designed to supply refrigerant from the refrigerant supply to the predetermined cooling point 118 by means of the pump 116 in a liquid or supercritical state of the refrigerant.

The cooling circuit 100 also includes a control unit 126. The control unit 126 is designed for timing the supply of the refrigerant to the predetermined cooling point 118 by means of the pump 116. The temporal control includes a point in time and/or a length of the supply of the refrigerant to the predetermined cooling point 118 by means of the pump 116. The control unit 126 is designed to control the supply of refrigerant to the predetermined cooling point 118 by means of the pump 116 at least based on one Temperature of the refrigerant compressor 102 and/or the compressor drive 104. The temporal control comprises a point in time and/or a length of time for the supply of the refrigerant to the refrigerant compressor 102 and/or the compressor drive 104.

The cooling circuit 100 further includes an optional aftercooler 128 for cooling the refrigerant from the refrigerant supply. The aftercooler 128 is designed to cool the refrigerant from the refrigerant supply to a temperature that is essentially identical to an ambient temperature of the cooling circuit 100 . As in figure 1 As shown, the aftercooler 128 is positioned between the pump 116 and the refrigerant compressor 102 . Deviating from the in figure 1 The embodiment shown can have the refrigerant compressor 102 a refrigerant compressor housing not shown in detail, in which the pump 116 is integrated.

The following is based on the figure 1 a method for operating the cooling circuit 100 is described. The refrigerant coming from the evaporator 112 is sucked in by means of the refrigerant compressor 102 . The sucked refrigerant is compressed by the refrigerant compressor 102 . This increases the pressure of the refrigerant. The compressed refrigerant is then discharged from the refrigerant compressor 102 and fed to the heat exchanger 106 where it is cooled by the heat exchanger 106 . The refrigerant can be recooled in supercritical operation and liquefied in subcritical operation. In any case, heat is extracted from the refrigerant. The cooled refrigerant is then supplied to the fluid collection space 108 . There it forms a refrigerant reserve. A portion of the refrigerant from the refrigerant supply is then fed to the expansion element 110, where the refrigerant expands. This part of the refrigerant is then fed to the evaporator 112, where it evaporates and is then sucked in again by the refrigerant compressor 102.

Another portion of the refrigerant from the refrigerant supply of the fluid collection space 108 is selectively supplied by the pump 116 to the predetermined cold spot 118 of the refrigerant compressor 102 and/or the compressor drive 104 by means of the pump 116 at a pressure above a discharge pressure of the refrigerant compressor 102. In particular, by means of the pump 116, the refrigerant from the refrigerant store is selectively supplied to the predetermined cooling point 118 of the refrigerant compressor 102 and/or the compressor drive 104 in an essentially single-phase state. Thus, the refrigerant from the refrigerant supply is supplied by the pump 116 to the predetermined cooling point 118 of the refrigerant compressor 102 and/or the predetermined cooling point 118 of the compressor drive 104 in a liquid or supercritical state. If, for example, a temperature of the refrigerant compressor 102 exceeds a predetermined threshold value, but not a temperature of the compressor drive 104, the refrigerant is supplied exclusively to the predetermined cooling point 118 of the refrigerant compressor 102. For example, if a temperature of the compressor drive 104 exceeds a predetermined threshold value, but not a temperature of the refrigerant compressor 102 , the refrigerant is supplied exclusively to the predetermined cooling point 118 of the compressor drive 104 . On the other hand, if, for example, a temperature of both refrigerant compressor 102 and compressor drive 104 exceeds a predetermined threshold value, the refrigerant is supplied to predetermined cooling point 118 both of refrigerant compressor 102 and to predetermined cooling point 118 of compressor drive 104 . The exact point at which the coolant is supplied can be controlled by the control unit 126 . The control unit 126 temporally controls the supply of refrigerant, in particular the point in time and/or the length of the supply of refrigerant.

Optionally, the refrigerant from the refrigerant store can be cooled by means of the aftercooler 128 . In this case, the refrigerant from the refrigerant supply can be cooled by means of the aftercooler 128 to a temperature that is essentially identical to an ambient temperature of the cooling circuit 100 . For this purpose, the aftercooler 128 can be arranged between the pump 116 and the refrigerant compressor 102 .

Further details of the predetermined cold spot 118 are described below.

figure 2 a schematic representation of a possible cooling point 118. figure 2 shows a sectional view of the refrigerant compressor 102. The refrigerant compressor 102 can be a reciprocating compressor 130 with at least one working chamber 132 and with at least one piston 134. In this case, the piston 134 is movably arranged in the working chamber 132 . The working space 132 is defined by at least one valve plate 136 and a refrigerant compressor wall 138 limited. The valve plate 136 has at least one inlet valve 140 for admitting refrigerant from a suction chamber into the work space 136 and at least one outlet valve 142 for discharging compressed refrigerant from the work space 136 into a pressure chamber. As in figure 2 As shown, the predetermined cold spot 118 may include an underside 144 of the piston 134 . For example, the supply unit 114 is designed to spray the refrigerant onto the underside 144 of the piston 134 . To this end, the supply unit 114 may include at least one first injection nozzle 146 for spraying the refrigerant onto the underside 144 of the piston 134 . Accordingly, in operation, the refrigerant is sprayed onto the underside 144 of the piston 134 by the first injector 146 .

figure 3 shows a schematic representation of another possible cooling point 118. Only the differences to the cooling point of the figure 2 described and the same or comparable components are provided with the same reference numerals. As in figure 3 As shown, the predetermined cold spot 118 may include the refrigerant compressor wall 138 . For this purpose, the refrigerant compressor wall 138 can have at least one refrigerant channel 148 . The refrigerant passage 148 may extend circumferentially around the piston 134 within the refrigerant compressor wall 138 . The supply unit 114 is fluidly connected to the refrigerant channel 148 of the refrigerant compressor wall 138 . Correspondingly, in operation, the refrigerant is supplied from the supply unit to the refrigerant channel 148 of the refrigerant compressor wall 138 .

figure 4 shows a schematic representation of another possible cooling point 118. Only the differences to the cooling point of the figure 2 described and the same or comparable components are provided with the same reference numerals. figure 4 shows a plan view of the refrigerant compressor 102. As in FIG figure 4 As shown, the predetermined cold spot 118 may include the valve plate 136 . For this purpose, the valve plate 136 can have at least one refrigerant channel 150 . The coolant channel 150 can extend within the valve plate 136 in such a way that coolant can flow through the valve plate 136 in the areas of the pressure chamber of the coolant compressor 102 and thus in the high-temperature area. The supply unit 114 is fluidly connected to the refrigerant channel 150 of the valve plate 136 . Accordingly, in operation, the refrigerant is supplied from the supply unit to the refrigerant channel 150 of the valve plate 136 .

figure 5 shows a schematic representation of another possible cooling point 118. Only the differences to the cooling point of the figure 2 described and the same or comparable components are provided with the same reference symbols. figure 5 shows a sectional view of the refrigerant compressor 102 and the compressor drive 104. The compressor drive 104 has, for example, an electric motor 152 with a stator 154 and a rotor 156. The electric motor 152 may be housed in a sealed motor housing 158 . In the exemplary embodiment shown, the predetermined cooling point 118 comprises the stator 154, the rotor 156 and/or a gap 160 between the stator 154 and the rotor 156. The supply unit 114 can be used to spray the refrigerant onto the stator 154, the rotor 156 and/or be formed in the gap 160 between the stator 154 and the rotor 156. For this purpose, the supply unit can have at least one second injection nozzle 162 for spraying the refrigerant onto the stator 154, the rotor 156 and/or into the gap 160 between the stator 154 and the rotor 156. Accordingly, in operation, the refrigerant is sprayed onto the stator 154, the rotor 156, and/or into the gap 160 between the stator 154 and the rotor 156 by the second injection nozzle 162. Optionally, the electric motor 152 can be connected to power electronics that are not shown in detail. In this case, the predetermined cooling point 118 comprises at least one component of the power electronics.

figure 6 shows a schematic representation of another possible cooling point 118. Only the differences to the cooling point of the figure 2 described and the same or comparable components are provided with the same reference numerals. As in figure 6 is shown, the invention is not limited to reciprocating compressors. Instead, the refrigerant compressor may be a scroll compressor 164 . The scroll compressor 164 may include a refrigerant passage 166 . The refrigerant channel 166 can be arranged in a so-called backplate 168 of the scroll compressor 164 and can be fluidly connected to the supply unit 114 . In this way, the refrigerant passage 166 of the scroll compressor 164 allows refrigerant to flow through the backplate 168 during operation.

Reference List

100

cooling circuit

102

refrigerant compressor

104

compressor drive

106

heat exchanger

108

fluid collection space

110

expansion organ

112

Evaporator

114

feeding unit

116

pump

118

refrigeration point

120

supply line

122

return line

124

refrigerant line

126

control unit

128

aftercooler

130

reciprocating compressor

132

working space

134

Pistons

136

valve plate

138

refrigerant compressor wall

140

intake valve

142

outlet valve

144

bottom of the flask

146

first injector

148

Refrigerant passage of the refrigerant compressor wall

150

Valve plate refrigerant channel

152

electric motor

154

stator

156

rotor

158

motor housing

160

Gap between the stator and the rotor

162

second injector

164

scroll compressor

166

Scroll compressor refrigerant passage

168

backplate

Claims (15)

Cooling circuit (100) comprising a refrigerant compressor (102) with a compressor drive (104) for driving the refrigerant compressor (102), a heat exchanger (106), in particular a condenser or gas cooler, with a fluid collection space (108), the fluid collection space (108) being designed to form a coolant supply from coolant, and a supply unit (114), the supply unit (114) having a pump (116), the supply unit (114) being connected to the fluid collection space (108) and the refrigerant compressor (102), the supply unit (114) for selectively supplying Refrigerant from the refrigerant reservoir to at least one predetermined cooling point (118) of the refrigerant compressor (102) and/or the compressor drive (104) by means of the pump (116) at a predetermined pressure above a discharge pressure of the refrigerant compressor (102). Cooling circuit (100) according to the preceding claim, wherein the supply unit (114) is connected to the refrigerant compressor (102) by means of at least one supply line (120) and to the heat exchanger (106) by means of at least one return line (122), the predetermined pressure being so is chosen so that it at least compensates for pressure losses in the supply line (120) and the return line (122). Cooling circuit (100) according to one of the preceding claims, wherein the refrigerant compressor (102) is a reciprocating piston compressor (130) with at least one working space (132) and with at least one piston (134), the piston (134) being movable in the working space (132 ) is arranged, wherein the working space (132) is delimited by at least one valve plate (136) and a refrigerant compressor wall (138), wherein the predetermined cooling point (118) comprises at least the refrigerant compressor wall (138), the valve plate (136) of the refrigerant compressor (102) and/or an underside (144) of the piston (134). Cooling circuit (100) according to the preceding claim, wherein the refrigerant compressor wall (138) and/or the valve plate (136) has at least one refrigerant channel (148, 150), the supply unit (114) being fluidly connected to the refrigerant channel (148, 150). Cooling circuit (100) according to one of the two preceding claims, wherein the supply unit (114) is designed for spraying the refrigerant onto the underside (144) of the piston (134). Refrigeration circuit (100) according to the preceding claim, wherein the supply unit (114) has at least a first injection nozzle (146) for spraying the refrigerant onto the underside (144) of the piston (134). Cooling circuit (100) according to one of the preceding claims, wherein the compressor drive (104) has an electric motor (152) with a stator (154) and a rotor (156), the predetermined cooling point (118) having the stator (154), the rotor (156), and/or a gap (160) between the stator (154) and the rotor (156). Refrigeration circuit (100) according to the preceding claim, wherein the supply unit (114) for spraying the refrigerant on the stator (154), the rotor (156), and / or in the gap (160) between the stator (154) and the rotor (156) is formed. Refrigeration circuit (100) according to the preceding claim, wherein the supply unit (114) has at least one second injection nozzle (162) for spraying the refrigerant onto the stator (154), the rotor (156), and/or into the gap (160) between the Stator (154) and the rotor (156). Cooling circuit (100) according to one of the three preceding claims, wherein the electric motor (152) is arranged in a sealed motor housing (158). Cooling circuit (100) according to one of the four preceding claims, wherein the electric motor (152) is connected to power electronics, wherein the predetermined cooling point (118) comprises at least one component of the power electronics. Cooling circuit (100) according to any one of the preceding claims, further comprising an aftercooler (128) for cooling the refrigerant from the refrigerant supply, in particular for cooling to a temperature which is essentially identical to an ambient temperature of the cooling circuit (100). Cooling circuit (100) according to one of the preceding claims, wherein the supply unit (114) is designed for supplying essentially single-phase refrigerant from the refrigerant supply to the compressor and/or compressor drive (104) and/or wherein the supply unit (114) is designed for supplying Refrigerant from the refrigerant supply to the predetermined cooling point (118) of the refrigerant compressor (102) and/or the compressor drive (104) is in a liquid or supercritical state. Cooling circuit (100) according to one of the preceding claims, further comprising a control unit (126), wherein the control unit (126) for timing the supply of the refrigerant to the predetermined cooling point (118) of the refrigerant compressor (102) and/or the compressor drive (104 ) is designed, wherein the control unit (126) is designed in particular to control the supply of the refrigerant to the predetermined cooling point (118) of the refrigerant compressor (102) and/or the compressor drive (104) at least based on a temperature of the refrigerant compressor (102) and / or the compressor drive (104), wherein the time control comprises in particular a point in time and/or a length of the supply of the refrigerant to the predetermined cooling point (118) of the refrigerant compressor (102) and/or the compressor drive (104). Method for operating a cooling circuit (100), the cooling circuit (100) having a refrigerant compressor (102) with a compressor drive (104) for driving the refrigerant compressor (102), a heat exchanger (106), in particular a condenser or gas cooler, with a fluid collection space (108 ), wherein the fluid collection space (108) is designed to form a refrigerant supply from refrigerant, and a supply unit (114), wherein the supply unit (114) is connected to the fluid collection space (108) and the refrigerant compressor (102), the method comprising: - suction of a refrigerant by means of the refrigerant compressor (102), - Compressing the refrigerant using the refrigerant compressor (102), - Cooling, in particular recooling and/or liquefaction, of the refrigerant by means of the heat exchanger (106), - supplying the chilled refrigerant to the fluid plenum (108), and - selectively supplying refrigerant from the refrigerant supply to at least one predetermined cooling point (118) of the refrigerant compressor (102) and/or the compressor drive (104) at a predetermined pressure above a discharge pressure of the refrigerant compressor (102).

Images