AU2022393093A1

AU2022393093A1 - Air-conditioning system

Info

Publication number: AU2022393093A1
Application number: AU2022393093A
Authority: AU
Inventors: Mathias Venschott
Original assignee: Truma Geraetetechnik GmbH and Co KG
Current assignee: Truma Geraetetechnik GmbH and Co KG
Priority date: 2021-11-18
Filing date: 2022-10-17
Publication date: 2024-05-02
Also published as: CN118265882A; DE102021005724A1; EP4433765A1; WO2023088577A1

Abstract

The invention relates to an air-conditioning system. A condenser fan (30) has regulable fan power. The compressor (3) has regulable compressor power. Two temperature sensors (61, 62) are associated with the evaporator (1) and the condenser (3). A third temperature sensor (63) measures an actual temperature outside the air-conditioning system. A control unit (5) has a regulatory effect on the condenser fan (30) and/or on the compressor (3), with the result that the air-conditioning system operates in one mode of at least two different modes.

Description

Air-Conditioning System

The present invention relates to an air-conditioning system.

The principle of cold production by means of a cooling circuit on which air cooling is based is described, for example, in document WO 2007/042065 Al. At least two fans and two heat exchangers are in most cases provided in such air conditioning systems. One fan and an associated heat exchanger belong to the evaporator in which the air of the room to be cooled is cooled by the interaction with the refrigerant. A further fan and an associated heat exchanger belong to the condenser in which thermal energy of the refrigerant is transferred to the ambient air and is thus dissipated.

The process of transfer of the thermal energy of the room air to the exterior air requires electrical energy which is usually provided via the local electrical grid or, where appropriate, the battery of a vehicle (a mobile home or a caravan, for example). Nowadays, the general aim is to keep the energy demand as low as possible. However, a pure reduction of the energy requirement may be contrary to the demands of user on the performance of the air-conditioning system. It is thus necessary to weigh up the energy demand against the performance of the air-conditioning system. Details as to the control of air-conditioning systems can be taken, for example, from documents DE 10 2007 055 006 Al, JP 6 739 671 Bl, DE 11 2017 002 005 T5, EP 1 923 240 A1, DE 10 2019 109 379 Al, CN 1 10 906 505 A or US 2014/0345307 Al.

Therefore, the object on which the invention is based is to propose an air conditioning system which allows a situation-appropriate and energy-efficient operation.

The invention achieves the object by an air-conditioning system comprising an evaporator, an evaporator fan, a condenser, a condenser fan, a compressor, an expansion element, a control unit, and at least three temperature sensors, the condenser fan assigned to the condenser being variable with regard to its fan performance, the compressor being variable with regard to its compression performance, wherein a first temperature sensor of the three temperature sensors is assigned to the evaporator, wherein a second temperature sensor of the three temperature sensors is assigned to the condenser, wherein a third temperature sensor of the three temperature sensors senses an actual temperature outside the air-conditioning system, wherein the control unit processes measured temperature values of the third temperature sensor with regard to a predeterminable temperature setpoint value, and wherein the control unit acts in a regulating manner on the condenser fan and/or the compressor, so that the air-conditioning system runs in one mode of at least two different modes.

A control unit is provided in the air-conditioning system according to the invention, which acts on a variable condenser fan and/or a variable compressor. It is thus possible to adjust the performance of the two components and thus the energy requirement thereof. This serves to allow the operation of the air conditioning system in one respective mode of at least two different modes. One mode is a mode of operation which takes the needs of the user of the air conditioning system and/or the energy requirement into account. Some modes and the respective characteristics are discussed below in different embodiments of the air-conditioning system.

For regulation, the control unit uses measured data of three temperature sensors. Two of the temperature sensors are assigned to the evaporator and the condenser to measure the temperature there. Part of the following embodiments refers to the two temperature sensors for determining internal temperatures. The third temperature sensor measures the temperature outside the air-conditioning system and preferably the temperature of the air which is to be tempered by the air-conditioning system. Therefore, this is the actual temperature which is to be brought to a setpoint temperature which can be determined by a user. The control unit therefore has a total of three measured temperature values and one setpoint temperature value to regulate the air-conditioning system in accordance with the at least two operating modes.

One embodiment involves that the evaporator fan assigned to the evaporator is variable with regard to its fan performance, and that the control unit acts in a regulating manner on the evaporator fan, so that the air-conditioning system runs in one mode. In this embodiment, a total of three variable components are present, which are regulated individually or together by the control unit such that the respective mode is achieved: the evaporator fan, the condenser fan and the compressor. Based on this embodiment, it is thus provided that the control unit acts in a regulating manner on the evaporator fan and/or the condenser fan and/or the compressor depending on the mode.

In the following two embodiments, it is explained how the first and/or the second temperature sensor are designed or positioned.

One embodiment provides that the first temperature sensor is configured and arranged such that the first temperature sensor senses temperature values in an area of the evaporator in which a phase change of the refrigerant occurs.

An alternative or additional embodiment involves that the second temperature sensor is configured and arranged such that the second temperature sensor senses temperature values in an area of the condenser in which a phase change of the refrigerant occurs.

The two aforementioned embodiments each relate to the phase change of the refrigerant in the evaporator or the condenser. For an optimum regulation, it is provided that the temperature is respectively measured at which the phase change in the respective component of the air-conditioning system occurs. If the temperature is respectively measured in the range of the phase change, the pressure to which the refrigerant is subjected results from the temperature depending on the properties of the refrigerant.

One embodiment provides that the control unit processes the measured temperature values of the first temperature sensor and the second temperature sensor so as to obtain information about a pressure of a refrigerant in the evaporator and the condenser. In this embodiment, the control unit uses the measured values of the first and the second temperature sensor to obtain information about the pressure at which the respective phase change of the refrigerant occurs.

The following embodiments refer to modes in which the air-conditioning system can be operated. The modes are each designated with a purely exemplary name to make a distinction between them easier. Therefore, the designations are only intended to provide an overview and are purely arbitrary, so that they can be omitted or replaced with numbers, for example.

One embodiment involves that in a "cool max" mode, the control unit acts in a regulating manner on the evaporator fan and/or the condenser fan and/or the compressor depending on the predeterminable setpoint temperature and the measured temperature values of the third temperature sensor, such that the air conditioning system runs at a maximum power. In the "cool max" mode, the air conditioning system is operated such that the setpoint temperature is obtained as quickly as possible, i.e. the difference between the actual temperature in the room to be cooled and the predetermined setpoint temperature is reduced as quickly as possible. In one embodiment, the evaporator fan and the condenser fan are operated at maximum fan performance, and the compressor is operated at maximum compression performance. This result in a high cooling performance of the air-conditioning system which is operated with a high air exchange rate (i.e. with the supply of fresh air) or a high air circulation (i.e. in a recirculation mode). This mode is thus used to reach the room-air temperature desired by the user as quickly as possible.

One embodiment provides that in a "minimum current consumption" mode, the control unit acts in a regulating manner on the evaporator fan and/or the condenser fan such that the pressure of the refrigerant in the evaporator is equal to the pressure of the refrigerant in the condenser within a predeterminable tolerance range. In this mode, the aim is that the air-conditioning system requires as little electrical current as possible. To this end, the evaporator fan and/or the condenser fan are/is regulated such that the pressure of the refrigerant in the evaporator is as equal as possible to the pressure of the refrigerant in the condenser. Both pressures should at least not differ from each other outside a tolerance range. This reduces the energy requirement of the compressor which is located between the evaporator and the condenser in the cooling circuit.

An alternative or additional embodiment involves that in a "minimum current consumption" mode, the control unit acts in a regulating manner on the condenser fan, such that the pressure of the refrigerant in the condenser is in a minimum range. In this embodiment, the control unit operates the condenser fan such that the pressure of the refrigerant in the condenser is as low as possible.

A further alternative or additional embodiment provides that in the "minimum current consumption" mode, the control unit increases the fan performance of the evaporator fan to reduce the pressure of the refrigerant in the condenser.

In the aforementioned embodiments with regard to the mode referred to as "minimum current consumption" mode, the control unit intervenes such that a pressure difference between the pressures of the refrigerant in the evaporator and in the condenser is as low as possible. If in one embodiment, the exterior air is guided with a high pressure loss through the condenser, the control unit increases the fan performance of the condenser fan by increasing the speed of this fan. As a result, more air volume flow is conveyed, and the pressure of the refrigerant in the condenser decreases. This results in an increase of the current consumption of the condenser fan, but the compressor requires significantly less electrical energy. This is relevant as the compressor usually requires more energy than the fan devices.

One embodiment involves that in a "silent" mode, the control unit acts in a regulating manner on the evaporator fan and the condenser fan, such that the fan performances are each in a predeterminable minimum range, and that in the "silent" mode, the control unit acts on the compressor depending on the setpoint temperature and the measured temperature values of the third temperature sensor. In this embodiment, the noise generation is thus reduced by operating the two variable fans at the lowest possible performance, for example at a minimum speed. The temperature is regulated by acting on the compressor.

One embodiment provides that in the "silent" mode and in the event that the pressure of the refrigerant in the compressor is above a limit value, the control unit reduces the compression performance of the compressor and/or the fan performance of the condenser fan. If the pressure of the refrigerant in the compressor increases too much, either the compression performance of the compressor is reduced or the fan performance of the condenser is increased in the so-called "silent" mode in this embodiment. Alternatively, both interventions can take place.

One embodiment involves that the air-conditioning system is adapted to be connected to a rechargeable energy storage unit, that the control unit determines an amount of energy stored in the energy storage unit - preferably via an inlet voltage of the energy storage unit, and that in an "optimum accumulator operation" mode, the control unit acts in a regulating manner on the evaporator fan and/or the condenser fan and/or the compressor based on the setpoint temperature which can be entered, the determined amount of energy, and a predeterminable running time, such that the air-conditioning system maintains the actual temperature within a predeterminable limit range until the end of the running time. In this embodiment, the air-conditioning system obtains the electrical energy from a rechargeable energy storage unit. This is provided by an accumulator, for example. The control unit determines the amount of energy present in the energy storage unit by evaluating the input voltage of the energy storage unit, for example. In this embodiment, the air-conditioning system is operated in an "optimum accumulator operation" mode. To this end, a setpoint temperature and a desired running time of the air-conditioning system are to be specified by a user. The control unit regulates the air-conditioning system depending on the amount of energy available. The predeterminable limit range for the actual temperature is the range within which the actual temperature may differ from the setpoint temperature without the cooling performance of the air conditioning system having to be modified.

One embodiment provides that in a "test" mode, the control unit acts in a regulating manner on the evaporator fan and/or the condenser fan and/or the compressor such that the refrigerant in the evaporator has a predeterminable evaporator test pressure and/or the refrigerant in the condenser has a predeterminable condenser test pressure, that the control unit determines a value of a current consumption of the compressor, and that the control unit derives information as to whether there is a loss of refrigerant on the basis of the determined value of the current consumption and stored data. Due to the variable fans, predetermined pressures of the refrigerant are generated in the evaporator and/or the condenser. Based on the measurement of the current consumption of the compressor and the comparison with a stored characteristic map, the control unit can for example check whether refrigerant has escaped.

In the two following embodiments, one of two temperature sensors respectively determines whether there is an icing of the associated component. Therefore, additional sensors for this monitoring can be omitted. The two embodiments differ from each other as to whether the air-conditioning system is operated in a cooling mode or in a heating mode. Therefore, the circuit of the refrigerant is operated in different directions so that the room air is either cooled or heated.

One embodiment involves that in a cooling mode of the air-conditioning system, the control unit evaluates the measured temperature values of the first temperature sensor which is assigned to the evaporator as to whether the evaporator is iced up.

One embodiment provides that in a heating mode of the air-conditioning system, the control unit evaluates the measured temperature values of the second temperature sensor which is assigned to the condenser as to whether the condenser is iced up.

One embodiment involves that the control unit evaluates the measured temperature values of the second temperature sensor which is assigned to the condenser as to whether a pressure of the refrigerant in the condenser is within a permissible pressure range. By knowing the pressure through the temperature measurement, impermissibly high pressures can be avoided. This may influence the selection of materials and wall thicknesses.

One embodiment provides that the air-conditioning system is portable. In this embodiment, the air-conditioning system is configured with regard to the dimensions and the weight thereof, such that it can be carried by a user, for example.

More specifically, there are numerous possibilities to configure and further develop the air-conditioning system according to the invention. For this purpose, reference is made, on the one hand, to the claims subordinate to claim 1 and, on the other hand, to the description below of example embodiments in conjunction with the drawing, in which:

Fig. 1 shows a schematic representation of an air-conditioning system.

Figure 1 shows a schematic view of the structure of an air-conditioning system.

In the air-conditioning system according to the cold vapor compression refrigerating circuit, a refrigerant circulates which changes phase from liquid/vaporous to gaseous in an evaporator 1 and changes phase from gaseous to liquid within the condenser 3. During the phase change in the evaporator 1 and the condenser, the temperature and the pressure are constant. The respective values of the pressure and the temperature are fixedly assigned to each other due to the thermodynamic properties of the refrigerant used, such that a pressure value results from a temperature measurement.

In the evaporator 1, the refrigerant passes through the following states: after expansion in the expansion element 4, the refrigerant enters the evaporator 1 substantially in a vaporous state. The gas content is low, and the liquid content is high. Within the evaporator 1, the gas content increases until there is no more liquid content. This is the phase change. The last section of the evaporator 1 is used to overheat the refrigerant. It is thus ensured that the subsequent compressor 2 is only supplied with gaseous refrigerant. The subsequent compressor 2 compresses the gaseous refrigerant. In the condenser 3, the refrigerant passes through the following states: the refrigerant is first cooled (so called de-heating section). This is followed by a phase change from gaseous to liquid. In the last section of the condenser 3, the refrigerant is undercooled so that it is in any case in a liquid form at the inlet of the subsequent expansion device 4. In some refrigeration circuits, the overheating and/or undercooling sections are outside the evaporator 1 or the condenser 3. A so-called internal heat exchanger is then often used.

In the illustrated embodiment, a variable-speed compressor 2, a variable speed condenser fan 30 and even a variable-speed evaporator fan 10 are provided for the operation of the different modes. The term "variable" is to be understood such that the speeds can respectively be changed continuously or in steps.

Furthermore, the evaporator 1 and the condenser 3 are each provided with a temperature sensor 61, 62. The first temperature sensor 61 and the second temperature sensor 62 are located on the refrigerant tubes (not illustrated here) at that point at which the refrigerant undergoes a phase change. These phase change areas are determined in advance under different conditions (such as limit values for the temperatures and the relative humidity with which the air conditioning system is used, and minimum and maximum speeds of the variable fan and the variable compressor). In one embodiment, the temperature measuring point is located in the middle in the refrigerant tube loop of the respective heat exchanger of the evaporator or the condenser. In the case of multi-flow heat exchangers, for example, several temperature sensors are provided in one embodiment, the measured values of which are averaged. Alternatively, the temperature is only measured in one line. By measuring the evaporation or condensation temperature, the thermodynamic properties of the refrigerant can be used to draw conclusions about the evaporation or condensation pressure.

Generally, it can be stated that the lower the delivery stroke to be achieved by the compressor 2, the lower the current consumption and thus the power consumption thereof. Furthermore, The compressor 2 usually has the highest current or power consumption compared to the demand of the two fans 10, 30.

The "cool max" mode is for example described:

The user of the air-conditioning system is in a room with a temperature of 35°C and 50% relative humidity. The air conditioner exchanges the air guided through the condenser 3 with the environment outside the room via two hoses (one for suction and one for blowing out) which are not illustrated here. It is therefore a so-called two-channel room conditioner. The air passing through the evaporator 1 is directed in the room as recirculated air. The user sets its room air conditioner to a setpoint temperature of 23°C. The air-conditioning system will now cool the room as quickly as possible to the setpoint temperature with the maximum available cooling performance. The control unit 5 then reduces the performance of the compressor 2 and/or the performance of the evaporator fan 10 and/or the condenser fan 30 and then regulates such that the room temperature remains substantially constant.

In the proposed method, the air-conditioning system can determine the high and the low pressure (i.e. the condensation or evaporation pressure) and try to keep the pressure difference as low as possible. This allows additional operating modes of the air-conditioning system as described above.

List of Reference Numerals

1 evaporator 2 compressor 3 condenser 4 expansion element control unit evaporatorfan condenserfan 61 first temperature sensor 62 second temperature sensor 63 third temperature sensor 100 energy storage unit

Claims

1. An air-conditioning system

comprising an evaporator (1), an evaporator fan (10), a condenser (3), a condenser fan (30), a compressor (2), an expansion element (4), a control unit (5), and at least three temperature sensors (61, 62, 63),

the condenser fan (30) assigned to the condenser (3) being variable with regard to its fan performance,

the compressor (2) being variable with regard to its compression performance,

wherein a first temperature sensor (61) of the three temperature sensors (61, 62, 63) is assigned to the evaporator (1),

wherein a second temperature sensor (62) of the three temperature sensors (61, 62, 63) is assigned to the condenser (3),

wherein a third temperature sensor (63) of the three temperature sensors (61, 62, 63) senses an actual temperature outside the air-conditioning system,

wherein the control unit (5) processes measured temperature values of the third temperature sensor (63) with regard to a predeterminable temperature setpoint value, and

wherein the control unit (5) acts in a regulating manner on the condenser fan (20) and/or the compressor (2), so that the air-conditioning system runs in one mode of at least two different modes.

2. The air-conditioning system according to claim 1,

wherein the evaporator fan (10) assigned to the evaporator (1) is variable with regard to its fan performance, and

wherein the control unit (5) acts in a regulating manner on the evaporator fan (10), so that the air-conditioning system runs in one mode.

3. The air-conditioning system according to claim 1 or 2, wherein the first temperature sensor (61) is configured and arranged such that the first temperature sensor (61) senses temperature values in an area of the evaporator (1) in which a phase change of the refrigerant occurs, and/or wherein the second temperature sensor (62) is configured and arranged such that the second temperature sensor (62) senses temperature values in an area of the condenser (3), in which a phase change of the refrigerant occurs.

4. The air-conditioning system according to any of claims 1 to 3,

wherein the control unit (5) processes the measured temperature values of the first temperature sensor (61) and the second temperature sensor (62) so as to obtain information about a pressure of a refrigerant in the evaporator (1) and in the condenser (3).

5. The air-conditioning system according to any of claims 1 to 4,

wherein in a "minimum current consumption" mode, the control unit (5) acts in a regulating manner on the evaporator fan (10) and/or the condenser fan (30) such that the pressure of the refrigerant in the evaporator (1) is equal to the pressure of the refrigerant in the condenser (3) within a predeterminable tolerance range.

6. The air-conditioning system according to claim 4 or 5,

wherein in a "minimum current consumption" mode, the control unit (5) acts in a regulating manner on the condenser fan (30) such that the pressure of the refrigerant in the condenser (3) is in a minimum range.

7. The air-conditioning system according to claim 5 or 6,

wherein in the "minimum current consumption" mode, the control unit (5) increases the fan performance of the evaporator fan (10) to reduce the pressure of the refrigerant in the condenser (3).

8. The air-conditioning system according to any of claims 1 to 7,

wherein in a "silent" mode, the control unit (5) acts in a regulating manner on the evaporator fan (10) and the condenser fan (30) such that the fan performances are each in a predeterminable minimum range, wherein in the "silent" mode, the control unit (5) acts on the compressor (2) depending on the setpoint temperature and the measured temperature values of the third temperature sensor (63), and wherein in the "silent" mode, in the event that the pressure of the refrigerant in the compressor (2) is above a limit value, the control unit (5) reduces the compression performance of the compressor (2) and/or increases the fan performance of the condenser fan (30).

9. The air-conditioning system according to any of claims 1 to 8,

wherein the air-conditioning system is adapted to be connected to a rechargeable energy storage unit (100),

wherein the control unit (5) determines an amount of energy stored in the energy storage unit (100) - preferably via an inlet voltage of the energy storage unit (100), and

wherein in an "optimum accumulator operation" mode, the control unit (5) acts in a regulating manner on the evaporator fan (10) and/or the condenser fan (30) and/or the compressor (2) based on the setpoint temperature which can be entered, the determined amount of energy, and a predeterminable running time, such that the air-conditioning system maintains the actual temperature within a predeterminable limit range until the end of the running time.

10. The air-conditioning system according to any of claims 1 to 9,

wherein in a "test" mode, the control unit (5) acts in a regulating manner on the evaporator fan (10) and/or the condenser fan (30) and/or the compressor (2) such that the refrigerant in the evaporator (1) has a predeterminable evaporator test pressure and/or the refrigerant in the condenser (3) has a predeterminable condenser test pressure,

wherein the control unit (5) determines a value of a current consumption of the compressor (2), and

wherein the control unit (5) derives information as to whether there is a loss of refrigerant on the basis of the determined value of the current consumption and stored data.

11. The air-conditioning system according to any of claims 1 to 10, wherein the control unit (5) evaluates the measured temperature values of the second temperature sensor (62) which is assigned to the condenser (3) as to whether a pressure of the refrigerant in the condenser (3) is within an permissible pressure range.