Temperature management system, heat pump and method for controlling temperature of lubricant

Abstract

The invention relates to a temperature management system for a lubricant (3) contained in a lubricant reservoir (1) of a compressor system (2) for a heat pump for pumping a working medium. The invention also relates to a method for controlling the lubricant temperature of a lubricant (3) present in a lubricant reservoir (1) of a compressor system (2) for a heat pump for pumping a working medium. The invention also relates to a heat pump having a temperature management system designed according to the invention. The invention allows the temperature of the lubricant (3) to be set flexibly, dynamically and as required, thereby increasing the service life of the lubricant and improving the operating performance of the heat pump.

Description

Technical Field

[0001] This invention relates to a temperature management system for a lubricant present in a lubricant reservoir of a compressor system of a heat pump through which the working medium flows. The temperature management system includes a temperature measuring unit configured to measure the actual lubricant temperature; a control unit connected at the signal technology layer to the temperature measuring unit and configured to check whether the measured actual lubricant temperature is within a target lubricant temperature range; and a temperature control element connected at the signal technology layer to the control unit, configured to heat or cool the lubricant. Furthermore, the invention relates to a heat pump with such a temperature management system, particularly a high-temperature heat pump. Additionally, the invention relates to a method for controlling the lubricant temperature in a lubricant reservoir of a pump compressor system through which the working medium flows.

[0002] This invention is primarily (but not limited to) used in thermodynamic heating systems, such as heat pumps, particularly high-temperature heat pumps. However, its application in thermodynamic cooling systems, such as those in refrigerators or air conditioning systems, is not excluded. Background Technology

[0003] Heat pump technology is generally well-known. For example, a heat pump is used to absorb heat energy from a first external medium (such as ambient air or a liquid) using technical or mechanical work, thereby transferring it as useful energy or useful heat, in addition to driving energy, to a second external medium. The second external medium is the medium to be heated. When such a system is implemented in a geothermal plant, the first external medium can be provided by liquids contained in the soil rock; however, in industrial processes, waste heat can also be used as the first external medium.

[0004] Currently, heat pumps are primarily used for building heating. However, applications where heat pumps are used to generate heat required for industrial processes are also known. For industrial processes, high-temperature heat pumps with medium temperatures >100°C are typically used.

[0005] In DE 10 2011 086 476 A1, an example using a high-temperature heat pump clearly describes the basic principle of a heat pump. This heat pump has a fluid circuit for absorbing and delivering thermal energy, absorbing thermal energy from at least one first reservoir via a fluid (working medium), and delivering the thermal energy through the fluid to at least one second reservoir to heat the at least one second reservoir.

[0006] In addition to the evaporation, condensation, and expansion units, a heat pump (or high-temperature heat pump) typically includes a compressor for compressing the working medium circulating in the fluid loop. In the evaporation unit, the working medium, transported from a liquid to a gaseous state, is drawn into the compressor and compressed to the pressure level required for liquefaction. As the (e.g., electrically driven) compressor compresses the vapor working medium from a low outlet pressure level to a higher final pressure level, the temperature of the working medium increases. Various compressor variants are known in the art, such as reciprocating compressors, scroll compressors, screw compressors, rotary compressors, and rotary piston compressors (not exhaustive). For example, a reciprocating compressor is based on the principle that as the piston moves downward into a cylinder surrounding it, the moving piston draws in the gaseous working medium through a suction valve. As the piston undergoes upward motion, the working medium is compressed. In a reciprocating compressor, the intake valve is closed during the compression of the working medium. If the pressure in the cylinder exceeds the pressure level present on the high-pressure side of the compressor, the working medium exits the compressor via a pressure valve. Embodiments of other compressor types are omitted here as they are not relevant to the present invention. "Compressor" can be used synonymously with "compressor unit". The term "compressor system" will be used throughout this document because actual compressors typically interact directly with other components, such as the drive unit (e.g., an electric motor) that drives the compressor and the lubricant reservoir.

[0007] This invention relates to different designs of compressor systems, including open compressor systems, semi-hermetic compressor systems, or hermetic compressor systems. In an open compressor system, the drive unit (motor) is structurally separate from the compressor. The compressor's drive shaft extends from the housing and connects to the drive unit. In a semi-hermetic compressor system, the drive unit and compressor are arranged in a common housing. In a fully hermetic compressor system, the drive unit and compressor are also arranged in a common housing, but compared to a semi-hermetic compressor system, this is entirely welded externally.

[0008] Typically, the compressor or compressor system mentioned includes a lubricant reservoir for holding lubricant. Lubricant can also be understood as a lubricant mixture. Lubricant is used to lubricate components of the compressor or compressor system, particularly the moving parts of the compressor (e.g., pistons, cylinders, bearings, valves, etc.). Known lubricant reservoirs are commonly referred to as "oil sumps." However, because lubricants other than "oil" may also be involved, the term "lubricant reservoir" is used throughout this case. Oil or lubricant is drawn from the oil sump or lubricant reservoir and transported to the various points requiring lubrication.

[0009] It is known that during heat pump standstill, liquid working media (such as refrigerant) accumulate in the compressor's oil sump (lubricant reservoir) and mix with oil or lubricant, or gaseous working media dissolve into it. Consequently, the viscosity of the oil or lubricant decreases, and the lubrication effect diminishes. Other lubricating properties of the lubricant are also negatively affected by the working media dissolved in or mixed with it. If a mixture of lubricant and working media, rather than the lubricant itself, is delivered to the area to be lubricated, this can lead to reduced lubrication. Ultimately, this can result in increased friction between moving parts or in bearings, potentially leading to increased mechanical wear. To address this issue, oil or lubricant heaters are now used to heat the lubricant when the heat pump is stationary. One known form of such a heating system is the arrangement of electric heating rods in the oil sump or lubricant reservoir. Another known form is an electric heating strip around the oil sump or lubricant reservoir.

[0010] Before commissioning or starting the heat pump, it is essential to ensure that most of the working medium mixed or dissolved in the lubricant is drained from the lubricant. This is done by heating the lubricant.

[0011] During heat pump operation, it is essential to ensure the lubricant maintains optimal viscosity to provide the best possible lubrication. The viscosity of the lubricant—as described above—depends on the proportion of the working medium (such as refrigerant) dissolved or distributed within it, but also on the lubricant's temperature. The solubility of the working medium in the lubricant is determined by the lubricant's temperature and the pressure of the gaseous working medium present in the compressor system (particularly the lubricant reservoir). Previously used working media (e.g., hydrofluorocarbons such as R1 34a) have relatively low solubility in lubricants, while modern working media (hydrofluoroolefins) typically have significantly higher solubility. Therefore, for the operation of a heat pump compressor system, the lubricant must be maintained at a temperature level above the condensation temperature of the working medium (at a given pressure). Simultaneously, to maximize the lubricant's shelf life or service life, it is necessary to maintain the lubricant temperature as low as possible. Therefore, there is an increasing need for flexible, dynamic, and condition-appropriate temperature settings for the lubricants used in heat pump compressor systems. Summary of the Invention

[0012] Therefore, the object of this invention is to provide a temperature management system for a lubricant stored in a lubricant reservoir of a heat pump compressor system through which the working medium flows. This temperature management system is capable of flexibly, dynamically, and demand-appropriately setting the temperature of the lubricant to improve both the service life of the lubricant and the operating performance of the heat pump. The same division of labor is based on the heat pump and the method for controlling the lubricant temperature proposed in this invention.

[0013] To address this objective, a temperature management system having the features of claim 1, a heat pump having the features of claim 8, and a method having the features of claim 9 are proposed.

[0014] It should be noted that the features listed individually in each claim can be combined in any technically reasonable manner, and further embodiments of the invention are shown. In particular, the specification characterizes and designates the invention in conjunction with the accompanying drawings.

[0015] It should also be noted that the conjunction “and / or” used herein, which is placed between two features and connects them to each other, is always interpreted such that in the first embodiment according to the purpose of the invention, only the first feature may exist, in the second embodiment, only the second feature may exist, and in the third embodiment, both the first and second features may exist.

[0016] This invention relates to a temperature management system for a lubricant present in a lubricant reservoir of a heat pump compressor system through which the working medium flows. The temperature management system includes a temperature measuring unit configured to measure the actual lubricant temperature; a control unit connected to the temperature measuring unit at a signal technology layer and configured to check whether the measured actual lubricant temperature is within a target lubricant temperature range; and a temperature control element connected to the control unit at a signal technology layer, configured to heat or cool the lubricant. The temperature management system is characterized in that the control unit is configured to:

[0017] a. Whenever the actual lubricant temperature is higher than the target lubricant temperature range, the temperature control element cools the lubricant.

[0018] b. The temperature control element heats the lubricant whenever the actual lubricant temperature is below the target lubricant temperature range.

[0019] In the heat pump described herein, wherein a temperature management system according to the invention is used, the heat pump is preferably a high-temperature heat pump. The proposed temperature management system according to the invention exhibits particular advantages in high-temperature heat pumps where the external medium temperature for heat absorption is greater than 100°C. The compressor system may include one or more compressors of the type described above, but in particular, the invention is suitable for compressor systems based on one or more reciprocating compressors. If multiple reciprocating compressors are implemented in the compressor system, i.e., an arrangement of several reciprocating compressors, the reciprocating compressors can be supplied with lubricant from a common lubricant reservoir or from a separate lubricant reservoir. "Lubricant reservoir" can therefore also be understood as a single lubricant reservoir as well as multiple lubricant reservoirs. As mentioned at the beginning, an oil pan or oil sump may also be included in the lubricant reservoir, wherein the lubricant used need not be oil. The compressor system or compressor may include a crankcase (piston, connecting rod, and crankshaft) (i.e., having such a crankcase), as well as other components such as the cylinder head (gas flow and valve system) and the aforementioned lubricant reservoir.

[0020] The temperature management system includes a temperature measuring unit configured to measure the actual lubricant temperature present in the lubricant reservoir. If multiple independent lubricant reservoirs are provided, a separate temperature measuring unit can be assigned to each reservoir to measure the corresponding actual lubricant temperature present in each reservoir.

[0021] A "temperature measuring unit" is a unit suitable for measuring the material temperature of a lubricant at a given time. Where applicable, the temperature measuring unit used according to the invention can also measure the ambient temperature near the lubricant and derive or calculate the actual lubricant temperature from it.

[0022] The temperature measurement unit may include a measuring probe that is in direct contact with the lubricant and measures the actual lubricant temperature by means of contact measurement. Such a measuring probe may be called a contact thermometer, which requires thermal contact with the target (the lubricant to be measured or the ambient medium). Exemplary contact thermometers that can be used according to the invention include expansion thermometers, vapor pressure thermometers, thermocouples, resistance thermometers, temperature sensors (integrated circuits with temperature output), aluminum foil thermometers, temperature measuring hardeners, liquid crystal thermometers, and gas thermometers.

[0023] However, at the same time, the temperature measurement unit may include a measuring probe that measures the actual temperature of the lubricant without contact (i.e., without direct contact with the object being measured). Such a measuring probe may be called a non-contact thermometer. These may include the temperature radiation of the lubricant using an infrared sensor.

[0024] The temperature measurement unit, as previously described, is connected to the control unit at the signal technology level. "Connection at the signal technology level" means that one-way or two-way data transmission is possible. The actual lubricant temperature, or corresponding data, measured by the temperature measurement unit can therefore be forwarded to the control unit. The temperature measurement unit can perform data processing, such as preprocessing, and convert the raw data into the desired data format. However, this can also be done or supplemented within the control unit, and will not be elaborated further. The "connection at the signal technology level" can be wired or wireless (radio). Wireless connectivity can be specifically understood as electromagnetic transmission, such as radio connectivity, Bluetooth connectivity, or WLAN connectivity. Optical data transmission options are also considered wireless connectivity at the signal technology level. The control unit can be part of the compressor system housing, located close to the compressor system (e.g., within the housing of the control unit of a heat pump) or externally located. Furthermore, the control unit can be an external computing unit, server, cloud server, or the like.

[0025] The control unit—as previously described—is configured to check whether the measured actual lubricant temperature is within the target lubricant temperature range. To this end, the control unit may be configured to perform a calculated or algorithmic data comparison between the actual lubricant temperature and the target lubricant temperature range. The control unit may include a database storing target lubricant temperature range data, which has been determined, for example, based on empirical values, machine values, or others. Such a database may also be arranged externally to the control unit so that the control unit can access the data stored there via suitable signal and data connections. Similarly, the control unit may include a device via which the target lubricant temperature range can be dynamically adjusted according to a parameter (e.g., the pressure present in the lubricant reservoir) and can be based on a comparison with the actual lubricant temperature. To perform the aforementioned operations, the control unit may include a computing unit or a data processing unit. The control unit may have multiple signal connection interfaces via which it can be connected at the signal technology level to, for example, a temperature measurement unit, a temperature control unit, and, where applicable, to other components.

[0026] As described, the temperature management system includes temperature control elements connected to the control unit at the signal technology level. These temperature control elements are configured to heat or cool the lubricant. The temperature control elements can be formed, for example, as hollow chambers or channels through which a heating or cooling medium (e.g., water) can flow, integrated into or disposed therethrough a housing wall or base plate of a lubricant reservoir. Furthermore, the temperature control elements can be understood as multiple channels (i.e., a channel system) or multiple hollow chambers (i.e., a hollow chamber system) that are flowably connected to each other. Individual flow through multiple channels or hollow chambers is also possible. Therefore, the control unit can be connected to multiple temperature control elements at the signal technology level. The temperature control elements typically include a control and / or regulation unit, through which the supply line of the heating or cooling medium is controlled or regulated at a suitable temperature. For this purpose, the control and / or regulation unit can interact with suitable supply and discharge units (e.g., a pump), which can result in the supply (inflow) or discharge (outflow) of the heating or cooling medium and provide the desired heating or cooling temperature. In this scenario, the heating or cooling medium can originate from an external source of the heat pump, but it can also be heat energy supplied to the heat pump or heat absorbed by the heat pump, which is supplied to a temperature control unit or multiple temperature control units. It is also conceivable to provide a mixing unit that blends heating or cooling media at different temperatures to provide the desired heating or cooling temperature. The control unit can, in particular, be connected at the signal technology level to the control and / or regulation unit of the temperature control element.

[0027] If, by comparing the actual lubricant temperature with the target lubricant temperature range, it is determined in the control unit that the actual lubricant temperature is higher than the target lubricant temperature range (meaning a higher, i.e., warmer temperature), the control unit causes the temperature control element to cool the lubricant. To do this, the control unit may first generate a detection signal (based on the actual lubricant temperature being above the target lubricant temperature range), which is converted into a command signal. After the command signal is transmitted to the temperature control element or the control and / or regulating unit associated with the temperature control element, the lubricant is cooled by a cooling medium of appropriate temperature flowing through the temperature control element. The temperature to be set in the temperature control element (e.g., the cooling medium), which needs to cool the lubricant to such a degree that the actual lubricant temperature is again within the target lubricant temperature range, can be determined by the control and / or regulating unit assigned to the temperature control element, the control unit, or through the interaction of both units.

[0028] If, by comparing the actual lubricant temperature with the target lubricant temperature range, it is determined in the control unit that the actual lubricant temperature is lower than the target lubricant temperature range (meaning a lower, i.e., a colder temperature), the control unit causes the temperature control element to heat the lubricant. To do this, the control unit may first generate a detection signal (based on the actual lubricant temperature being lower than the target lubricant temperature range), which is converted into a command signal. After the command signal is transmitted to the temperature control element or the control and / or regulating unit assigned to the temperature control element, the lubricant is heated by a heating medium of appropriate temperature flowing through the temperature control element. The temperature to be set in the temperature control element (e.g., the heating medium), which needs to heat the lubricant to such a degree that the actual lubricant temperature is again within the target lubricant temperature range, can be determined by the control and / or regulating unit assigned to the temperature control element, the control unit, or through the interaction of both units.

[0029] The temperature management system according to the invention allows for flexible and dynamic adjustment of the lubricant temperature. The system allows for current-time temperature control of the lubricant and allows for adjustment of the lubricant temperature if necessary. This temperature management system is suitable for use in continuous operation, i.e., ongoing operation, which means continuous monitoring and adjustment of the lubricant temperature. This can also be done at fixed time intervals, alternatively or additionally at user-specified (i.e., desired) times.

[0030] Further advantageous embodiments of the temperature management system according to the invention arise from the features specified in the dependent claims and the features described below. Reference is also made to the features listed in the dependent claims.

[0031] A first embodiment of the temperature management system proposed according to the present invention may include a pressure measuring unit connected to the control unit at the signal technology level, the pressure measuring unit being configured to measure the pressure present in a lubricant reservoir. "Pressure" can also be understood as the vapor pressure of the working medium, which may be at least partially dissolved in the lubricant. In practice, the pressure may be measured at a housing portion of the compressor system connected to the lubricant reservoir, for example, in the crankcase. This pressure corresponds to the gas pressure (of the working medium) above the liquid lubricant in the lubricant reservoir. The crankcase and lubricant reservoir may be connected to the low-pressure side of the heat pump (evaporator, compressor gas inlet). The pressure need not be measured directly on the lubricant surface area in the lubricant reservoir; rather, proportional pressure may be taken or measured at another point in the compressor system without any problem.

[0032] Pressure can be measured continuously, at fixed time intervals, or at desired time points. The measured pressure values ​​are forwarded to the control unit. Preprocessing of the measured pressure values ​​can be performed in the pressure measurement unit, for example, providing the pressure values ​​in a data format suitable for further processing. Recorded or preprocessed pressure values ​​can also be processed in the control unit. The signal technology layer connection between the pressure measurement unit and the control unit can be wired or wireless. The pressure measurement unit may include a single pressure sensor, or it may be an arrangement including multiple pressure sensors. If multiple pressure sensors are provided, all pressure sensors can be connected to the control unit at the signal technology layer. Alternatively, it can be specified that the pressure sensors are connected to a common microcontroller at the signal technology layer, and the pressure value data collected there is jointly transmitted from the microcontroller to the signal-associated control unit. In the microcontroller or control unit, an average pressure value can be calculated from the pressure values ​​of the individual pressure sensors as the pressure of the lubricant reservoir (proportional to or corresponding to the gas pressure of the working medium).

[0033] In another embodiment of the temperature management system proposed according to the invention, a target lubricant temperature range can be defined with a lower lower limit, which corresponds to the condensation temperature of the working medium based on the pressure present in the lubricant reservoir. The condensation temperature is the temperature at which a substance (here, the working medium) condenses at a given pressure, i.e., changes from a gaseous state to a liquid state. The pressure present in the lubricant reservoir is measured using the pressure measuring unit and used to calculate the lower lower limit. Furthermore, other characteristic values ​​can also be used for calculation, such as lubricant-specific data or working medium-specific data, which are stored in the control unit or database. The target lubricant temperature range thus originates at least in part from the specific conditions predominant in the lubricant reservoir or compressor system (e.g., crankcase), which is why temperature control, and adjustments made by means of the temperature management system where applicable, are always suitable for this situation.

[0034] In another embodiment of the temperature management system proposed according to the present invention, a target lubricant temperature range may be defined with an upper temperature limit, which is 2K-15K higher than the condensation temperature of the working medium, preferably 5K-10K higher. The target lubricant temperature range determined by the aforementioned lower and upper temperature limits is primarily based on empirical values ​​to ensure reliable operation of the heat pump compressor system under actual lubricant temperatures within the target lubricant temperature range. This applies to startup, i.e., starting the system, and both operation, wherein adequate lubrication of the compressor components must be ensured.

[0035] In another embodiment of the temperature management system proposed according to the present invention, the control unit may be configured to identify a lower temperature limit at a predetermined time, i.e., taking into account the pressure measured in the lubricant reservoir at a specified time point. The calculation can be performed using software, calculation routines, or algorithms executed on the control unit. Furthermore, the control unit may be configured to dynamically adjust the target lubricant temperature range, i.e., taking into account the determined lower and upper temperature limits, the upper temperature limit being 2K-15K higher than the condensation temperature of the working medium, preferably 5K-10K higher. Dynamic adjustment can be understood as meaning that the target lubricant temperature range is suitable for the specific conditions that are dominant in the lubricant reservoir or compressor system at a given time. Therefore, the proportion of the working medium (e.g., a cooling medium) dissolved in or mixed with the lubricant is also considered, as this has a direct impact on the condensation temperature of the working medium and, if applicable, on the dominant pressure in the lubricant reservoir. The control unit is preferably configured to regulate the actual lubricant temperature so that it is always within the target lubricant temperature range to ensure adequate lubrication of the compressor components during compressor system or heat pump operation.

[0036] As mentioned at the beginning, the object of the present invention is also achieved by a heat pump, particularly a high-temperature heat pump, incorporating a temperature management system developed according to the present invention. When used in a high-temperature heat pump, what is particularly relevant to reliable performance is minimizing the amount of gaseous working medium dissolved in the lubricant of the compressor system during startup. Furthermore, the operation of a high-temperature heat pump also demonstrates the significant practical importance of reliable lubrication of compressor components. These requirements are ensured by implementing the temperature management system according to the present invention in the high-temperature heat pump.

[0037] As further mentioned at the beginning, the objective of this invention is also achieved through a method for controlling the temperature of a lubricant present in a lubricant reservoir of a heat pump compressor system through which the working medium flows. The method includes the following steps:

[0038] a. Measure the pressure present in the lubricant reservoir;

[0039] b. Based on the pressure measured in step a, identify the condensation temperature of the working medium;

[0040] c. Specify a target lubricant temperature range, wherein the lower limit of the target lubricant temperature range is the condensation temperature determined in step b, and wherein the upper limit of the target lubricant temperature range is 2K-15K higher than the condensation temperature of the working medium, preferably 5K-10K higher.

[0041] d. Measure the actual temperature of the lubricant;

[0042] e. Compare the actual lubricant temperature with the target lubricant temperature range, and then...

[0043] - Cool the lubricant whenever the actual lubricant temperature is higher than the target lubricant temperature range, or

[0044] - Heat the lubricant whenever the actual lubricant temperature is below the target lubricant temperature range.

[0045] It should be emphasized that the measured pressure corresponds to the condensation pressure of the working medium (e.g., refrigerant) in the lubricant reservoir or compressor system (e.g., the crankcase connected to the lubricant reservoir or other components). The condensation pressure can refer to the low-pressure side of the compressor system (evaporator, compressor gas inlet), as the lubricant reservoir and crankcase are directly connected to it. The (measurable) detectable pressure in the lubricant reservoir or associated crankcase (or other components of the compressor system) corresponds to or corresponds to the condensation pressure of the working medium. Based on the condensation pressure, the condensation temperature of the working medium can be calculated. However, for this purpose, other parameters, measured values, empirical data, etc., may also be included. However, the condensation temperature can also be calculated directly from the condensation pressure (where applicable, taking into account specific identification data of the working medium or the geometry or volume of the lubricant reservoir / crankcase or the space present – ​​filled with gas).

[0046] The method according to the invention can be performed continuously or at predetermined time intervals. Semi-continuous or non-continuous management of the method is therefore also possible. The method can be performed as needed, and in particular, it can be specified to be executed automatically, semi-automatically, or manually.

[0047] Furthermore, in the method according to the invention, the actual lubricant temperature can be specified to always be within the target lubricant temperature range. This ensures the stability of the lubricant temperature during the operation of the heat pump or associated compressor system. Therefore, adequate lubrication of the compressor components is always ensured during the operation of the compressor system or heat pump. Attached Figure Description

[0048] Further features and advantages of the present invention arise from the following description of non-limiting exemplary embodiments of the invention, which will be explained in more detail below with reference to the accompanying drawings. The drawings schematically illustrate:

[0049] Figure 1 This is the basic structure of the temperature management system according to the present invention;

[0050] Figure 2 It is a sequence of methods using the method proposed in this invention. Detailed Implementation

[0051] Figure 1The basic structure of a temperature management system for a lubricant 3, present in accordance with the invention, is schematically illustrated. The lubricant 3 is stored in a lubricant reservoir 1 of a heat pump compressor system 2. The temperature management system includes a temperature measuring unit 4 configured to measure the actual lubricant temperature of the lubricant 3. Figure 1 The temperature measuring unit 4 shown is in contact with the lubricant 3 via a contact thermometer 5. However, the temperature measuring unit 4 can also be configured in a non-contact manner. The temperature measuring unit 4 is integrated into the compressor system 2 or an associated housing (not shown).

[0052] Furthermore, the temperature management system includes a control unit 6, which is connected to the temperature measuring unit 4 at the signal technology level, for example, via a wired or wireless signal connection 7. Data exchange occurs between the temperature measuring unit 4 and the control unit 6 via the signal connection 7. Additionally, signal exchange for implementing control and regulation commands is performed via the signal connection 7. The control unit 6 is configured to check whether the measured actual lubricant temperature is within the target lubricant temperature range.

[0053] Furthermore, the temperature management system includes a temperature control element 9 connected to the control unit 6 at the signal technology level (i.e., via a wired or wireless signal connection 8), which is configured to heat or cool the lubricant 3. The temperature control element 9 is shown in a prominently patterned manner on the bottom side of the lubricant reservoir 1 in this embodiment. For example, the temperature control element 9 may be a cavity or channel through which a heating or cooling medium can flow, which is integrated into the cover surrounding the lubricant reservoir 1 or the housing of the lubricant reservoir 1.

[0054] Control unit 6 is configured to cause temperature control element 9 to cool lubricant 3 whenever the actual lubricant temperature is above the target lubricant temperature range. If the actual lubricant temperature is below the target lubricant temperature range, control unit 6 causes temperature control element 9 to heat lubricant 3. Related control and regulation commands are exchanged via signal connection 8 between control unit 6 and temperature control element 9. In the illustrated example, control and / or regulation unit 10 is inserted with respect to control unit 6 and temperature control element 9. Temperature control of temperature control element is regulated and controlled (in conjunction with control unit 6) via control and / or regulation unit 10. For example, the supply line of heating or cooling medium entering the channel or cavity of temperature control element 9 can be controlled or regulated at a suitable temperature via control and / or regulation unit 10. For this purpose, control and / or regulation unit 10 works in conjunction with suitable supply and discharge units (e.g., pumps) to cause the supply or discharge of heating or cooling medium.

[0055] like Figure 1As further shown, the control unit 6 (via a wireless or wired signal connection 12) is connected to the pressure measuring unit 11 at the signal technology level. The pressure measuring unit is configured to measure the pressure present in the lubricant reservoir 1. The pressure determined in this way can be used to calculate the lower limit of the target lubricant temperature range. The measured pressure represents the condensation pressure of the gaseous working medium of the heat pump in the lubricant reservoir.

[0056] Figure 2 The process sequence of the method according to the invention is illustrated in a highly stylized manner. The proposed method is aimed at controlling the temperature of a lubricant 3, i.e., the lubricant 3 is present in the lubricant reservoir 1 of the compressor system 2 of the heat pump through which the working medium flows.

[0057] In the first process step a., the pressure present in the lubricant reservoir 1 is measured (using pressure measuring unit 11). In the second process step b., the condensation temperature of the working medium is determined at the pressure measured in step a. The identification (calculation) of the condensation temperature is performed in control unit 6. In the subsequent process step c., a target lubricant temperature range is determined, wherein its lower limit is the condensation temperature of the working medium determined in step b., and wherein its upper limit is 2K-15K higher than the condensation temperature of the working medium, preferably 5K-10K higher. Process step c is also performed in control unit 6. In the subsequent step d., the actual temperature of the lubricant 3 is measured, i.e., measured using temperature measuring unit 4. Subsequently, in process step e., the actual lubricant temperature is compared with the target lubricant temperature range. If the actual lubricant temperature is higher than the target lubricant temperature range, the lubricant 3 is cooled. If the actual lubricant temperature is lower than the target lubricant temperature range, the lubricant 3 is heated. Figure 2 As indicated by the arrows, this method can be performed continuously, that is, by continuously checking the actual lubricant temperature, just as the temperature of lubricant 3 is continuously adjusted (e.g., if necessary).

[0058] List of reference numerals

[0059] 1. Lubricant reservoir

[0060] 2. Compressor System

[0061] 3. Lubricant

[0062] 4 Temperature Measurement Unit

[0063] 5. Contact thermometer

[0064] 6 Control Unit

[0065] 7. Signal Connection Section

[0066] 8. Signal connection section

[0067] 9 Temperature control components

[0068] 10 Control and / or regulation units

[0069] 11 Pressure Measurement Unit

[0070] 12 Signal Connection Section

Claims

1. A temperature management system for a lubricant, the lubricant being present in a lubricant reservoir (1) of a compressor system (2) of a heat pump through which a working medium (3) flows, the temperature management system comprising a temperature measuring unit (4) configured to measure the actual lubricant temperature of the lubricant (3); a control unit (6) connected at a signal technology level to the temperature measuring unit (4) and configured to check whether the measured actual lubricant temperature is within a target lubricant temperature range; and a temperature control element (9) connected at a signal technology level to the control unit (6) configured to heat or cool the lubricant (3), characterized in that, The control unit (6) is configured such that, a. Whenever the actual lubricant temperature is higher than the target lubricant temperature range, the temperature control element (9) cools the lubricant (3), and b. The temperature control element (9) heats the lubricant (3) whenever the actual lubricant temperature is lower than the target lubricant temperature range. The pressure measuring unit (11) is connected to the control unit (6) at the signal technology level. The pressure measuring unit is configured to measure the pressure present in the lubricant reservoir (1). The target lubricant temperature range has a lower limit, which corresponds to the condensation temperature of the working medium based on the pressure present in the lubricant reservoir. The target lubricant has an upper temperature limit, which is 2K-15K higher than the condensation temperature of the working medium. The control unit (6) is configured to identify the lower limit of the temperature at a predetermined time, i.e., taking into account the pressure measured in the lubricant reservoir (1) at a specified time point.

2. The temperature management system according to claim 1, characterized in that, The control unit (6) is configured to dynamically adjust the target lubricant temperature range, i.e., taking into account the determined lower and upper temperature limits, the upper temperature limit being 2K-15K higher than the condensation temperature of the working medium.

3. The temperature management system according to claim 1 or 2, characterized in that, The control unit (6) is configured to adjust the actual lubricant temperature so that it is always within the target lubricant temperature range.

4. A heat pump comprising a temperature management system according to any one of claims 1 to 3.

5. A method for regulating the temperature of a lubricant, said lubricant being present in a lubricant reservoir (1) of a heat pump compressor system (2) through which a working medium (3) flows, said method comprising the steps of: a. Measure the pressure present in the lubricant reservoir (1) at a specified time point; b. Based on the pressure measured in step a, identify the condensation temperature of the working medium; c. Specify a target lubricant temperature range, wherein the lower limit of the target lubricant temperature range is the condensation temperature determined in step b, and wherein the upper limit of the target lubricant temperature range is 2K-15K higher than the condensation temperature of the working medium; d. Measure the actual lubricant temperature of the lubricant (3); e. Compare the actual lubricant temperature with the target lubricant temperature range, and then... - Cool the lubricant (3) whenever the actual lubricant temperature is higher than the target lubricant temperature range, or - Heat the lubricant (3) whenever the actual lubricant temperature is lower than the target lubricant temperature range.

6. The method according to claim 5, characterized in that, The method is performed continuously or at specified time intervals.

7. The method according to claim 5 or 6, characterized in that, The actual lubricant temperature is controlled so that it is always within the target lubricant temperature range.

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