RU2562834C1 - Refrigerator and refrigerating system operation method - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: refrigerating system comprises an evaporator designed so that it can be placed in thermal contact with a cooled compartment, a compressor, a condenser, an expanding element and channels. The channels unite the evaporator, compressor, capacitor and expanding element. The method includes instantaneous determination of the required cold quantity for the compartment based on a drop between the preset temperature and actual temperature averaged in time. Then the variable quantity of need is generated in regard to the instantaneous required quantity of cold. The variable quantity of need is represented as the ratio of duration of the compressor on state to the duration of the compressor off state. The first interval of time is fixed when the compressor is on and the second interval of time is fixed when the compressor is off based on the variable quantity of need. The compressor is switched on and off in compliance with the first and second intervals of time. The refrigerating system also comprises the first cut-out valve placed in the channel passing between the condenser and evaporator, at that the method includes the closure of the first cut-out valve in result of the compressor switching off and opening of the first cut-out valve in result of the compressor switching on.

EFFECT: additional decrease in power consumption by refrigerating systems.

37 cl, 5 dwg

Description

Technical field

The present invention relates to a method for operating a refrigeration system. The present invention further relates to a refrigerator comprising a chamber cooled by a refrigeration system.

BACKGROUND OF THE INVENTION

The refrigeration system used with refrigerated household and industrial chambers for storing food products contains: an evaporator, compressor, condenser and expansion element, such as a capillary tube, mutually connected through channels. Such refrigerated household and industrial food storage chambers may represent part of refrigerators maintaining the temperature above the freezing point, or refrigerators maintaining the temperature below the freezing point, the latter sometimes referred to as freezers. Hereinafter, both types will be referred to as refrigerators.

The refrigerant circulates in the refrigeration system during operation of the compressor, which compresses the gaseous refrigerant coming from the evaporator. During the circulation of the refrigerant, the gaseous refrigerant cools and condenses to a liquid state in the condenser, which is located outside the chamber. Next, the liquid refrigerant is exposed to a differential pressure in the expansion element and evaporates from the liquid state in the evaporator. The evaporator is in thermal contact with the chamber. In this way, the chamber is cooled by a refrigerant.

The refrigeration system is designed to provide specific cooling capacity. The refrigeration system provides specific cooling capacity when a steady “on” state is reached after a certain period of compressor operation. The specific cooling capacity is higher than the required long-term cooling of the chamber. Thus, the compressor operates during the first period of time, the working period, and does not work during the second period of time, the non-working period. One compressor cycle during operation of the refrigeration system provides one working period and one non-working period. Accordingly, during operation in the refrigeration system, several compressor cycles occur. The operation of the compressor and the duration of its cycle depends on the temperature inside the chamber. Frequently used compressor control parameters are the maximum allowable temperature in the chamber at which the compressor starts to work, and the minimum temperature at which the compressor stops working.

EP 727628 discloses a control device for controlling temperature in a refrigerator and a method for controlling temperature in refrigerators. The aim is to provide a control device and a method for controlling temperature in refrigerators, through which it is possible to control a cooling source to reduce the energy consumption of the refrigerator. This is achieved through a control algorithm in which a demand variable is created. The created demand variable indicates the ratio of the duration of the on state (the above working period) of the cooling source to the duration of the off state (the above idle period) of the cooling source. In addition, the actual temperature, averaged over time, is used as the actual temperature to obtain the difference between the set temperature and the actual temperature.

During each compressor cycle, the refrigeration system undergoes cyclical losses. Losses result from the following: 1. The liquid refrigerant, instead of the gaseous refrigerant, leaves the evaporator at the beginning of the operating period. 2. Gaseous refrigerant is pumped through an expansion element in the form of a capillary tube until a hydraulic shutter is formed at the beginning of the working period. 3. Incorrect filling of the condenser and evaporator before establishing equilibrium during the working period. 4. Gaseous and liquid refrigerant enters the evaporator through the expansion element during the non-working period. In addition, a high starting current may be necessary depending on the type of compressor operating mode, which may also contribute to losses in systems containing a refrigeration system.

In refrigeration systems operating with long compressor cycles, cyclic losses can be neglected compared to the total energy consumption of the refrigeration system. However, in refrigeration systems operating with short-term cycles, cyclical losses can cause a significant amount of energy to be consumed by the refrigeration system. Reducing energy consumption by refrigerators has been a goal for many years. For example, the EC Directive 92/75 / EC gives the labeling of energy efficiency classes used inter alia for refrigerators. Thus, refrigerator manufacturers are striving to get a good rate of energy consumption.

The control device and method according to EP 727628 do not take into account cyclic losses in the respective refrigeration system.

Document WO 2006/044787 relates to a pressure equalization system that provides a solution to a problem specific to HVAC systems (heating, ventilation and air heating). In view of the prior art, it is stated that the pressure tends to equalize between the low pressure side and the high pressure side when the compressor stops operating, and that during the cooling cycle, the energy must create high pressure in the compressor at startup. In HVAC systems, however, the pressure does not equalize between the condenser and the evaporator (high pressure side and low pressure side of the refrigeration system) during non-working periods of the compressor. In view of this, there is a need for additional components that provide a high pressure drop when starting the compressor. The pressure equalization system according to WO 2006/044787 comprises a drain port connecting the compressor high pressure side to the compressor low pressure side (compressor outlet with compressor inlet). Through the drain, the pressure level in the compressor can be balanced to a low pressure level. Thus, the compressor can be started at low differential pressures. Accordingly, for an electrical system that provides compressor operation, neither an expensive starting capacitor nor a starting relay is needed.

There is a need to reduce energy consumption for some types of refrigeration systems.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to further reduce energy consumption in refrigeration systems.

According to one aspect, this goal is achieved by a method of operating a refrigeration system, the refrigeration system comprising:

- an evaporator configured to be placed in thermal contact with a cooled chamber,

- compressor

- capacitor

an expansion element, and

- channels connecting the evaporator, compressor, condenser and expansion element to each other. The method includes:

- the establishment of an instant need for cold for the camera based on the difference between the set temperature and the actual temperature, averaged over time,

- the formation of a variable demand value relative to the instantaneous required amount of cold, while the variable demand is the ratio of the duration of the on state of the compressor to the duration of the off state of the compressor,

- fixing the first period of time during which the compressor is turned on, and the second period of time during which the compressor is turned off, based on a variable demand, and

- turning on and off the compressor in accordance with the first and second time intervals. The refrigeration system further comprises a first shutoff valve located in a channel extending between the condenser and the evaporator. The method further includes:

- closing the first shutoff valve in connection with turning off the compressor, and

- opening the first shutoff valve in connection with the inclusion of the compressor.

Since according to the method, which provides the optimal duration of the cooling cycle from the point of view of energy consumption, in addition, the first shut-off valve closes when the compressor is turned off and does not reopen until the compressor is turned on again, to maintain the pressure differential between the condenser and the evaporator of the refrigeration system when the compressor, the cyclical losses in the refrigeration system described above in paragraphs 1-4 are eliminated, at least to a large extent. As a result, the above goal is achieved.

The refrigeration system and chamber may form part of a refrigerator, such as a domestic or industrial refrigerator for food. The average temperature can, for example, be calculated over a fixed period of time or for a series of compressor cycles. The sign “ratio of compressor on-time to compressor off-time” covers both alternative ratio calculations, i.e. the duration of the on state relative to the duration of the off state, as well as the duration of the off state relative to the duration of the on state of the compressor. A variable demand in the form of a ratio of the duration of the on state to the duration of the off state of the compressor can be applied for one duration of the compressor cycle in order to establish a first time period and a second time period. The duration of the compressor cycle can be fixed or can be set several times, for example, to save the number of compressor cycles per unit of time in a given interval, for example 1-8 cycles / hour. More specifically, the channel in which the first shutoff valve is located is the channel in which the expansion element is also located.

In accordance with embodiments, the refrigeration system may comprise a chamber, wherein the chamber may be designed to store food at home. Thus, the refrigeration system and the chamber can form part of a domestic refrigerator.

In accordance with embodiments, the compressor may be a single speed compressor controlled by a control system to operate at a constant speed for a first period of time. Thanks to this method, a relatively simple compressor can be operated in an economical manner. The compressor, and more particularly the electric motor driving the compressor, may be equipped with a starting capacitor and / or starting relay and / or other means for starting under conditions of high differential pressure prevailing between the inlet side and the outlet side of the compressor by closing the first shut-off valve in during the second period of time.

In accordance with embodiments, the refrigeration system may further comprise a valve mechanism located in the channel between the compressor and the condenser and a bypass channel extending between the compressor discharge side and the compressor inlet side. The method may further include:

- balancing the differential pressure between the exhaust side and the compressor inlet side for a second period of time. Thus, for example, a single-speed compressor can be started in conditions of low differential pressure, and a starting capacitor or other means can be eliminated, since the differential pressure between the inlet side and the outlet side of the compressor is equalized by the bypass channel.

In accordance with embodiments, the valve mechanism may include a check valve, and the refrigeration system may further comprise a second shutoff valve located in the bypass channel. The method may further include:

- keeping the second shutoff valve closed for a first period of time, and

- opening the second shutoff valve for a second period of time to achieve the specified equalization of the differential pressure.

In accordance with embodiments, the valve mechanism may include a 3-way valve, wherein the 3-way valve is connected to the bypass channel. The specified differential pressure equalization may include:

- opening the connection of the exhaust side of the compressor to the bypass channel and closing the connection of the compressor to the condenser by means of a 3-way valve. The method may further include:

- closing the connection of the exhaust side of the compressor with the bypass channel and opening the connection of the compressor to the condenser by means of a 3-way valve for the first time period.

In accordance with embodiments, the expansion member may comprise a capillary tube.

In accordance with embodiments, the first shutoff valve may form part of the expansion member.

In accordance with embodiments, the combined duration of the first time period and the second time period may be 1-100 minutes. That is, the compressor cycle may have a specified duration. In accordance with other embodiments, the combined duration of the first time period and the second time period may be 3-30 minutes. In general, the short total duration of the first and second time intervals, i.e. short compressor cycle times are advantageous in terms of energy consumption. In addition, the shorter compressor cycle time provides a more uniform air temperature inside the chamber cooled by the evaporator. In addition, a higher humidity inside the chamber can be achieved.

In accordance with embodiments, the compressor may be configured to provide cooling capacity in the range of 10 to 500 W according to ASHRAE LBP or HMBP. In accordance with further embodiments, the compressor may be configured to provide cooling capacity in the range of 20-300 watts according to ASHRAE LBP or HMBP. Such a compressor can provide sufficient cooling capacity for most home refrigeration applications.

In accordance with a further aspect, the aforementioned goal is achieved by a refrigerator comprising a chamber cooled by a refrigeration system controlled by a control system, the refrigeration system comprising: an evaporator in thermal contact with the chamber, a compressor, a condenser, an expansion element, and channels connecting each other is an evaporator, compressor, condenser and expansion element. The control system is intended:

- to establish the instant need for cold for the camera based on the difference between the set temperature and the actual temperature, averaged over time,

- to form a variable demand value relative to the instantaneous required amount of cold, while the variable demand value is the ratio of the duration of the compressor on state to the duration of the compressor off state,

- for fixing the first period of time during which the compressor is turned on, and the second period of time during which the compressor is turned off, based on a variable demand, and

- to turn the compressor on and off in accordance with the first and second time intervals. The refrigeration system contains a first shutoff valve located in the channel passing between the condenser and the evaporator, while the control system is additionally designed:

- to close the first shutoff valve in connection with turning off the compressor, and

- to open the first shut-off valve in connection with the inclusion of the compressor.

The embodiments described above for the method and the refrigeration system according to the method can be implemented in the refrigerator.

In accordance with embodiments, the compressor may be a single speed compressor controlled by a control system to operate at a constant speed for a first period of time.

In accordance with embodiments, the refrigeration system may further comprise a valve mechanism located in the channel between the compressor and the condenser and a bypass channel extending between the compressor discharge side and the compressor inlet side.

In accordance with embodiments, the valve mechanism may include a check valve, and the refrigeration system may further comprise a second shutoff valve located in the bypass channel, the control system may be configured to:

- holding the second shutoff valve in a closed state for a first period of time, and

- opening the second shutoff valve for a second period of time to equalize the differential pressure between the exhaust side and the compressor inlet side for a second period of time.

In accordance with embodiments, the valve mechanism may include a 3-way valve, wherein the 3-way valve is connected to the bypass channel. The control system may be configured to:

- opening the connection of the exhaust side of the compressor to the bypass channel and closing the connection of the compressor to the condenser via a 3-way valve for a second period of time, and

- closing the connection of the exhaust side of the compressor to the bypass channel and opening the connection of the compressor to the condenser by means of a 3-way valve for the first time period.

In accordance with embodiments, the compressor may alternatively be a variable speed compressor controlled by a control system for operating at variable speed for a first time period. Thus, it is possible to provide a compressor that starts up under conditions of high differential pressure.

In accordance with embodiments, the refrigeration system may include a filter located in the channel between the condenser and the expansion element.

In accordance with embodiments, a first shutoff valve may be located in the channel between the filter and the expansion member. Thus, it can be ensured that when the first shut-off valve is opened in connection with the compressor being turned on, liquid refrigerant will flow into the expansion element.

Additional features and advantages of the present invention will become apparent upon examination of the appended claims and the following detailed description. It will be apparent to those skilled in the art that the various features of the present invention can be combined to create embodiments other than those described below without departing from the scope of the present invention as defined in the appended claims.

A brief description of the graphic materials

Various aspects of the present invention, including its specific features and advantages, can be easily understood from the following detailed description and accompanying drawings, in which:

in FIG. 1 schematically shows a refrigerator in accordance with embodiments and a refrigeration system in accordance with embodiments,

in FIG. 2 shows a method of operating a refrigeration system in accordance with embodiments,

in FIG. 3 and 4 show portions of refrigeration systems in accordance with embodiments, and

in FIG. 5 shows a refrigeration system in accordance with embodiments.

Detailed description

The present invention will now be described in more detail with reference to graphic materials, which depict examples of embodiments. However, the present invention should not be construed as limited by the embodiments set forth herein. The disclosed features of examples of embodiments can be combined, as is obvious to a person skilled in the art to which the present invention relates. In this description, like reference numbers refer to like elements.

Well-known functions or constructions will not necessarily be described in detail for brevity and / or clarity.

In FIG. 1 schematically shows a refrigerator 2 in accordance with embodiments and a refrigeration system 4 in accordance with embodiments. The refrigerator 2 comprises a refrigeration system 4 and a chamber 6, for example, for storing food. The refrigeration system 4 includes an evaporator 8, a compressor 10, a condenser 12, a filter 14 and an expansion element 15 containing a capillary tube 16. The channels are designed to interconnect these components of the refrigeration system 4. Accordingly, the filter 14 is located in the channel passing between the condenser 12 and the expansion element 15.

The refrigerant circulates in the refrigeration system 4. The circulation of the refrigerant is provided by the differential pressure between the condenser 12 and the evaporator 8. The differential pressure is created by the compressor 10, compressing the gaseous refrigerant vaporized from the liquid refrigerant in the evaporator 8. The gaseous refrigerant is cooled and condenses to a liquid state in the condenser 12. The liquid the refrigerant passes through a filter 14, which is capable of trapping particles and water in the refrigerant. In the expansion element 15, the liquid refrigerant is subjected to a differential pressure to evaporate subsequently from the liquid state in the evaporator 8. The evaporator 8 is in thermal contact with the chamber 6 and thus cools the chamber 6 during evaporation of the refrigerant in the evaporator 8.

The refrigeration system 4 further comprises a first shut-off valve 20 located in a first channel 22 passing between the condenser 12 and the evaporator 8, i.e. channel 22 also contains an expansion element 15. The first shutoff valve 20 is located in the first channel 22 between the filter 14 and the expansion element 15. The first channel 22 can be closed by the first shutoff valve 20. The first shutoff valve 20 has two separate positions, one fully closed position and one fully open position.

The electric motor 24 drives the compressor 10. The control system 26 is designed to control the operation of the refrigeration system 4. The control system 26 may comprise a microprocessor programmed to regulate the operation of the refrigeration system 4. Alternatively, the control system 26 may comprise separate electrical components connected to control the refrigeration system 4 The control system 26 further comprises a temperature sensor 28 located in the chamber 6 and connected to the motor 24 for regulating compressor 10 and with the first shut-off valve 20. The control parameters of the refrigeration system 4 can be set in the control system 26. Alternatively, at least some control parameters may be set by the control panel 30.

In FIG. 2 shows a method of operating a refrigeration system in accordance with embodiments. The refrigeration system may be the refrigeration system 4 described for FIG. 1. The method includes:

- establishing 100 instantaneous cold demand for chamber 6 based on the difference between the set temperature and the actual temperature averaged over time. The set temperature can be set in the control system 26, for example, by means of a control panel 30. The time-averaged temperature can be calculated by the control system 26 using temperature measurements from the temperature sensor 28 in the chamber 6. The specified setting 100 of the instantaneous required amount of cold can include determining whether the refrigeration system 4 needs to be turned on or off, i.e. whether it is necessary to turn on compressor 10 or not.

- Formation 102 of a variable demand quantity relative to the instantaneous required amount of cold. The demand variable may be the ratio of the on-time of the compressor 10 to the off-time of the compressor 10.

- Fixing 104 of the first time period during which the compressor 10 is turned on and the second time period during which the compressor 10 is turned off, based on a variable demand quantity. For example, if the compressor cycle time is 20 minutes and the demand variable is 40% of the on state and 60% of the off state, the first time period is 8 minutes and the second time period is 12 minutes.

- Turning on 106 and turning off 108 of the compressor 10 in accordance with the first and second time intervals. The control system 26 is configured to turn the compressor 10 on and off by turning the motor 24 on and off.

- Closing 110 of the first shutoff valve 20 due to shutdown of the compressor 10.

- Opening 112 of the first shutoff valve 20 in connection with the inclusion of the compressor 10.

It can be clarified that in a refrigeration system not containing a first shut-off valve operated in accordance with this method, the pressure between the condenser 12 and the evaporator 8 is gradually equalized by the expansion element 15 during the compressor off times, causing the cyclic losses described in paragraph 1 above -four.

An advantage of the refrigeration system 4 operated in accordance with this method is that, firstly, due to the use of a variable demand value and a time-averaged temperature, the compressor 10 operates at an optimal duration in terms of the required amount of refrigeration and energy consumption. Secondly, by closing and opening the first shut-off valve 20, cyclic losses in the refrigeration system 4 can be avoided, at least to a large extent. Thus, the method allows you to operate the refrigeration system 4 with low energy consumption by optimizing performance and eliminating cyclic losses.

The process steps 100-104 are performed appropriately at regular intervals by the control system 16 of the refrigeration system 4. The process steps 106-112 can be performed at the same equal time intervals or different time intervals.

According to the method disclosed in connection with FIG. 2, it can accordingly be concluded that the control system 26 shown in FIG. 1 is configured to:

- establishing the instantaneous required amount of cold for the chamber 6 on the basis of the difference between the set temperature and the actual temperature averaged over time,

- the formation of a variable demand value relative to the instantaneous required amount of cold, while the variable demand is the ratio of the duration of the on state of the compressor 10 to the duration of the off state of the compressor 10,

- fixing the first period of time during which the compressor 10 is turned on, and the second period of time during which the compressor 10 is turned off, based on a variable demand,

- turning on and off the compressor 10 in accordance with the first and second time intervals,

- closing the first shutoff valve 20 in connection with the shutdown of the compressor 10, and

- opening the first shutoff valve 20 in connection with the inclusion of the compressor 10.

The compressor 10 may be a single speed compressor or controlled by a control system 26 to operate at a constant speed for a first period of time. That is, the electric motor 24 has only one operating speed, and the control system 26 is configured to turn the electric motor 24 on and off. The control system 26 may include a starting capacitor and / or a starting relay for starting the compressor 10 at a high pressure maintained in the capacitor 12, and on the exhaust side of the compressor by closing the first shut-off valve 20 for a second period of time with the compressor 10 turned off.

Alternatively, the compressor 10 may be a variable speed compressor controlled by a control system 26 for operating at a variable speed for a first period of time. That is, the control system can control the electric motor 24 both at at least two different speeds during one first period of time, and alternatively at a constant speed for one first period of time and at an excellent constant speed for the next first period of time. According to the latter alternative, the demand variable according to the method can be stored in a predetermined interval. If the demand variable is outside the predetermined interval, the constant speed increases or decreases depending on whether the variable demand is above or below the predetermined interval in the next first time interval. The variable speed compressor and its electric motor are capable of starting at a high pressure drop between the capacitor 12, i.e. the discharge side of the compressor 10, and the evaporator 8, i.e. compressor inlet side 10.

The compressor 10, single-speed or variable speed, can be configured to provide cooling capacity in the range of 10-500 W in accordance with the ASHRAE LBP standard or the HMBP standard (at a condensation temperature of 55 degrees Celsius and an evaporation temperature of 23.3 degrees Celsius). More specifically, in some applications, the compressor 10 may be configured to provide cooling capacities in the range of 20-300 watts in accordance with the ASHRAE LBP standard or the HMBP standard. The combined duration of the first time period and the second time period may be 1-100 minutes, i.e. the compressor cycle time can be 1-100 minutes. More specifically, the combined duration of the first time period and the second time period may be 3-30 minutes.

In FIG. 3 shows part of a refrigeration system 4 in accordance with embodiments. According to these embodiments, a solution is provided that enables the start-up of the compressor 10, such as a single-speed compressor, under conditions of low differential pressure, despite the high pressure prevailing in the condenser 12 located downstream of the compressor 10. The refrigeration system 4 comprises a valve mechanism 32 in the channel 34 between the compressor 10 and the condenser 12. The bypass channel 36 passes between the exhaust side of the compressor 10 and the inlet side of the compressor 10. The valve mechanism 32 includes a check valve 38. The second the check valve 40 is located in the bypass channel 36. When the second check valve 40 is open, any pressure difference between the inlet side and the discharge side of the compressor 10 is almost equal to the pressure prevailing on the inlet side of the compressor 10. The check valve 38 ensures that the high pressure in the condenser 10 will not be aligned upstream of the capacitor 10.

The second shutoff valve 40 is connected to the control system 26 of the refrigeration system 4. The control system 26 is configured to:

- holding the second shutoff valve 40 in a closed state for a first period of time during operation of the compressor 10, and

- opening the second shutoff valve 40 for a second period of time to equalize the differential pressure between the exhaust side and the inlet side of the compressor 10 during the second period of time when the compressor 10 is not running. Accordingly, the method shown in FIG. 2 may further include:

- balancing 114 differential pressure between the exhaust side and the inlet side of the compressor 10 for a second period of time.

- Opening 116 of the second shutoff valve 40 for a second period of time to achieve the indicated equalization 114 of the differential pressure between the exhaust side and the inlet side of the compressor 10 for a second period of time.

- Keeping 118 of the second shutoff valve 40 closed for a first period of time.

In FIG. 4 shows part of a refrigeration system 4 in accordance with embodiments. Also, these embodiments provide a solution that enables the compressor 10 to start up under conditions of low pressure drop, despite the high pressure prevailing in the condenser 12. The refrigeration system 4 comprises a valve mechanism 32 in the channel 34 between the compressor 10 and the condenser 12. The bypass channel 36 passes between the outlet side of the compressor 10 and the inlet side of the compressor 10. By the bypass channel 36, any pressure difference between the inlet side and the outlet side of the compressor 10 can be almost equalized to the pressure prevailing on the inlet side of the compressor 10. The valve mechanism 32 includes a 3-way valve 42. A 3-way valve is connected to the bypass channel 36.

The 3-way valve is connected to the control system 26 of the refrigeration system 4. The control system 26 is intended for:

- opening the connection between the exhaust side of the compressor 10 and the bypass channel 36 and closing the connection between the compressor 10 and the condenser 12 by means of a 3-way valve 42 during the second period of time when the compressor 10 is not working, to equalize the pressure by the bypass channel 36, and

- closing the connection between the exhaust side of the compressor 10 and the bypass channel 26 and opening the connection between the compressor 10 and the condenser 12 by means of a 3-way valve during the first period of time when the compressor 10 is running.

Accordingly, the method shown in FIG. 2 may include:

- equalization 114 differential pressure between the exhaust side and the inlet side of the compressor 10 for a second period of time, while the specified alignment 114 differential pressure includes:

- opening 120 of the connection between the exhaust side of the compressor 10 and the bypass channel 36 and closing 122 of the connection between the compressor 10 and the condenser 12 by means of a 3-way valve 42.

The method may further include:

- closing the connection 124 between the exhaust side of the compressor 10 and the bypass channel 36 and opening 126 the connection between the compressor 10 and the condenser 12 by means of a 3-way valve 42 for the first time period.

Thanks to the embodiments shown in FIG. 3 and 4, for a compressor with a constant speed, neither a starting capacitor nor any other means for starting is needed, despite the high pressure prevailing in the capacitor 12. The embodiments shown in FIG. 3 and 4 can be used in refrigeration systems 4 in accordance with FIG. 1 and 5.

In FIG. 5 shows a refrigeration system 4 in accordance with embodiments. The refrigeration system 4 comprises an evaporator 8, a compressor 10, a condenser 12 and an expansion element 15. The expansion element 15 comprises a first shut-off valve 20, or, in other words, a first shut-off valve 20 forms part of the expansion element 15. Accordingly, when the compressor 10 is operating and the liquid the refrigerant is vaporized in the evaporator 8, the first shut-off valve 20 acts as an expansion valve for liquid refrigerant. When the compressor 10 is not running, the first shut-off valve 20 closes, preventing cyclic losses in the refrigeration system 4. The control system 26 of the refrigeration system 4 controls inter alia the first shut-off valve 20.

The refrigeration system 4 in accordance with the embodiments may be operated according to the method in accordance with the embodiments for a period of time. With this in mind, for other periods of time, the refrigeration system 4 can be operated according to another method, for example, if the difference between the set temperature and the actual temperature exceeds a threshold value.

The illustrative embodiments and components described above can be combined, which is obvious to a person skilled in the art. Accordingly, when some components related to a compressor are mentioned herein, for example, a starting capacitor, the expression “compressor” encompasses the compressor motor.

Although the invention has been described with reference to examples of embodiments, many different changes, modifications, and the like will become apparent to those skilled in the art. For example, a check valve 38 according to the embodiments shown in FIG. 3 may be located in a channel extending between the evaporator 8 and compressor 10 upstream of the bypass channel 36. Similarly, the 3-way valve 42 according to the embodiments shown in FIG. 4 may be located in a channel extending between the evaporator 8 and the compressor 10, and may be connected to the compressor inlet side in the bypass channel 36.

Therefore, it should be understood that the foregoing is an illustrative example of various embodiments, and the invention should not be limited to certain disclosed embodiments, and it is intended that modifications of the disclosed embodiments, combinations of features of the disclosed embodiments, as well as other embodiments are included within the scope of the attached claims inventions.

As used here, the term “comprising” or “comprises” is non-limiting and includes one or more of the claimed features, elements, steps, components or functions, but does not exclude the presence or addition of one or more additional features, elements, steps, components, functions or their groups.

As used in the present description, the term "and / or" includes any combination and all combinations of one or more of the corresponding listed objects.

As used herein, the expression “for example”, derived from the Latin phrase “exempli gratia”, can be used to introduce or clarify a general example or examples of the previously mentioned object, and is not intended to limit such an object. As used here, the abbreviation "ie" can be used to clarify a specific object from a more general enumeration.

The terminology used here is intended only to describe certain embodiments and is not intended to limit the invention. As used in the present description, it is assumed that the singular also includes the plural, unless the context clearly indicates otherwise.

Unless otherwise indicated, all terms (including technical and scientific terms) used herein have the generally accepted meaning used by those skilled in the art to which this invention pertains. It should also be understood that terms, such as those defined in common dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technical field, and will not be interpreted in an idealized or overly formal sense unless explicitly stated otherwise here.

It should be understood that, despite the fact that the terms "first", "second", "third", etc. can be used in this application to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer or region from another element, component, region, layer or region. Thus, the first element, component, region, layer or region described here can be called the second element, component, region, layer or region without going beyond the scope of the idea of the present invention.

Claims (37)

1. The method of operation of the refrigeration system (4), where the refrigeration system (4) contains:
an evaporator (8) configured to be in thermal contact with the cooled chamber (6), a compressor (10), a condenser (12), an expansion element (15) and channels interconnecting the evaporator (8), a compressor (10), a condenser (12) and an expansion element (15), the method comprising:
- determination (100) of the instantaneous required amount of cold for the chamber (6) based on the difference between the set temperature and the actual temperature averaged over time
- the formation (102) of a variable demand value relative to the instantaneous required amount of cold, while the variable demand value is the ratio of the duration of the on state of the compressor (10) to the duration of the off state of the compressor (10),
- fixing (104) the first period of time during which the compressor (10) is turned on and the second period of time during which the compressor (10) is turned off, based on the variable demand, and turning on (106) and turning off (108) the compressor ( 10) in accordance with the first and second period of time,
characterized in that
the refrigeration system (4) comprises a first shutoff valve (20) located in the channel passing between the condenser (12) and the evaporator (8), the method comprising:
- closing (110) the first shutoff valve (20) in connection with the shutdown (108) of the compressor (10), and
- opening (112) of the first shut-off valve (20) in connection with the inclusion (106) of the compressor (10). 2. The method according to p. 1, characterized in that the refrigeration system (4) contains a chamber (6), while the chamber (6) is designed to store food at home. 3. The method according to p. 1, characterized in that the compressor (10) is a single-speed compressor controlled by a control system to operate at a constant speed for the first period of time. 4. The method according to p. 2, characterized in that the compressor (10) is a single-speed compressor, controlled by a control system to operate at constant speed for the first period of time. 5. The method according to p. 3, characterized in that the refrigeration system (4) further comprises a valve mechanism (32) in the channel between the compressor (10) and the condenser (12), and
the bypass channel (36) passing between the outlet side of the compressor (10) and the inlet side of the compressor (10), and the method further includes:
- equalization (114) of the differential pressure between the exhaust side and the inlet side of the compressor (10) for a second period of time. 6. The method according to p. 4, characterized in that the refrigeration system (4) further comprises a valve mechanism (32) in the channel between the compressor (10) and the condenser (12), and
the bypass channel (36) passing between the outlet side of the compressor (10) and the inlet side of the compressor (10), and the method further includes:
- equalization (114) of the differential pressure between the exhaust side and the inlet side of the compressor (10) for a second period of time. 7. The method according to p. 5, characterized in that the valve mechanism (32) contains a check valve (38), and the refrigeration system (4) further comprises a second shut-off valve (40) located in the bypass channel (36), and wherein the method further includes:
- holding (118) the second shutoff valve (40) in a closed state for a first period of time, and
- opening (116) the second shutoff valve (40) for a second period of time to achieve the specified equalization (114) differential pressure. 8. The method according to p. 6, characterized in that the valve mechanism (32) contains a check valve (38), and the refrigeration system (4) further comprises a second shut-off valve (40) located in the bypass channel (36), and wherein the method further includes:
- holding (118) the second shutoff valve (40) in a closed state for a first period of time, and
- opening (116) the second shutoff valve (40) for a second period of time to achieve the specified equalization (114) differential pressure. 9. The method according to p. 5, characterized in that the valve mechanism (32) comprises a 3-way valve (42), while the 3-way valve (42) is connected to the bypass channel (36), and wherein said alignment (114) ) differential pressure includes:
- opening (120) the connection between the exhaust side of the compressor (10) and the bypass channel (36) and closing (122) the connection between the compressor (10) and the condenser (12) by means of a 3-way valve (42), and the method further includes :
- closing (124) the connection between the outlet side of the compressor (10) and the bypass channel (36) and opening (126) the connection between the compressor (10) and the condenser (12) by means of a 3-way valve (42) for the first period of time. 10. The method according to p. 6, characterized in that the valve mechanism (32) contains a 3-way valve (42), while the 3-way valve (42) is connected to the bypass channel (36), and the specified alignment (114 ) differential pressure includes:
- opening (120) the connection between the exhaust side of the compressor (10) and the bypass channel (36) and closing (122) the connection between the compressor (10) and the condenser (12) by means of a 3-way valve (42), and the method further includes :
- closing (124) the connection between the outlet side of the compressor (10) and the bypass channel (36) and opening (126) the connection between the compressor (10) and the condenser (12) by means of a 3-way valve (42) for the first period of time. 11. The method according to any one of paragraphs. 1-10, characterized in that the expansion element (15) contains a capillary tube (16). 12. The method according to any one of paragraphs. 1-10, characterized in that the first shut-off valve (20) forms part of the expansion element (15). 13. The method according to any one of paragraphs. 1-10, characterized in that the combined duration of the first period of time and the second period of time is 1-100 minutes. 14. The method according to p. 11, characterized in that the combined duration of the first period of time and the second period of time is 1-100 minutes. 15. The method according to p. 12, characterized in that the combined duration of the first time period and the second time period is 1-100 minutes. 16. The method according to any one of paragraphs. 1-10, 14, 15, characterized in that the compressor (10) is configured to provide cooling capacity in the range of 10-500 W according to ASHRAE LBP or HMBP. 17. The method according to p. 11, characterized in that the compressor (10) is configured to provide cooling capacity in the range of 10-500 watts according to ASHRAE LBP or HMBP. 18. The method according to p. 12, characterized in that the compressor (10) is configured to provide cooling capacity in the range of 10-500 W according to the ASHRAE LBP standard or the HMBP standard. 19. The method according to p. 13, characterized in that the compressor (10) is configured to provide cooling capacity in the range of 10-500 watts according to ASHRAE LBP or HMBP. 20. A refrigerator containing a chamber (6) cooled by a refrigeration system (4) controlled by a control system (26), the refrigeration system (4) comprising:
an evaporator (8) in thermal contact with the chamber (6), a compressor (10), a condenser (12), an expansion element (15) and channels interconnecting the evaporator (8), a compressor (10), a condenser (12) and an expansion element (15), and wherein the control system (26) is configured to:
- establishing the instantaneous required amount of cold for the chamber (6) based on the difference between the set temperature and the actual temperature, averaged over time,
- the formation of a variable demand value relative to the instantaneous required amount of cold, while the variable demand value is the ratio of the duration of the on state of the compressor (10) to the duration of the off state of the compressor (10),
- fixing the first period of time during which the compressor (10) is turned on, and the second period of time during which the compressor (10) is turned off, based on a variable demand, and
- turning on and off the compressor (10) in accordance with the first and second time intervals,
characterized in that
the refrigeration system (4) comprises a first shut-off valve (20) located in a channel passing between the condenser (12) and the evaporator (8), and the control system (26) is further configured to:
- closing the first shut-off valve (20) in connection with turning off the compressor (10), and
- opening the first shut-off valve (20) in connection with the inclusion of the compressor (10). 21. The refrigerator according to claim 20, characterized in that the chamber (6) is designed to store food at home. 22. Refrigerator according to any one of paragraphs. 20 or 21, characterized in that the compressor (10) is a single-speed compressor, controlled by a control system (26) to operate at a constant speed for a first period of time. 23. The refrigerator according to claim 22, characterized in that the refrigeration system (4) further comprises a valve mechanism (32) in the channel between the compressor (10) and the condenser (12), and wherein the bypass channel (36) passes between the exhaust side of the compressor (10) and compressor inlet side (10). 24. The refrigerator according to claim 23, wherein the valve mechanism (32) comprises a check valve (38), and the refrigeration system (4) further comprises a second shut-off valve (40) located in the bypass channel (36), and wherein control system (26) is configured to:
- keeping the second shutoff valve (40) closed for a first period of time, and
- opening the second shutoff valve (40) for a second period of time to equalize the differential pressure between the exhaust side and the inlet side of the compressor (10) for a second period of time. 25. The refrigerator according to claim 23, wherein the valve mechanism (32) comprises a 3-way valve (42), wherein the 3-way valve (42) is connected to the bypass channel (36), and the system (26) control is configured to:
- opening the connection between the exhaust side of the compressor (10) and the bypass channel (36) and closing the connection between the compressor (10) and the condenser (12) by means of a 3-way valve (42) for a second period of time, and
- closing the connection between the exhaust side of the compressor (10) and the bypass channel (36) and opening the connection between the compressor (10) and the condenser (12) by means of a 3-way valve (42) during the first period of time. 26. A refrigerator according to claim 20, characterized in that the compressor (10) is a variable speed compressor controlled by a variable speed control system (26) for operating for a first period of time. 27. Refrigerator according to claim 21, characterized in that the compressor (10) is a variable speed compressor controlled by a variable speed control system (26) for operating at a first time period. 28. The refrigerator according to any one of paragraphs. 20, 21, 23-27, characterized in that the expansion element (15) contains a capillary tube (16). 29. A refrigerator according to claim 22, characterized in that the expansion element (15) comprises a capillary tube (16). 30. Refrigerator according to any one of paragraphs. 20, 21, 23-27, characterized in that the first shut-off valve (20) forms part of the expansion element (15). 31. A refrigerator according to claim 22, characterized in that the first shut-off valve (20) forms part of the expansion element (15). 32. Refrigerator according to any one of paragraphs. 20, 21, 23-27, 29, 31, characterized in that the refrigeration system (4) comprises a filter (14) located in the channel between the condenser (12) and the expansion element (15). 33. A refrigerator according to claim 22, characterized in that the refrigeration system (4) comprises a filter (14) located in the channel between the condenser (12) and the expansion element (15). 34. A refrigerator according to claim 28, characterized in that the refrigeration system (4) comprises a filter (14) located in the channel between the condenser (12) and the expansion element (15). 35. The refrigerator according to claim 30, characterized in that the refrigeration system (4) comprises a filter (14) located in the channel between the condenser (12) and the expansion element (15). 36. A refrigerator according to claim 32, characterized in that the first shut-off valve (20) is located in the channel between the filter (14) and the expansion element (15). 37. The refrigerator according to any one of paragraphs. 33-35, characterized in that the first shut-off valve (20) is located in the channel between the filter (14) and the expansion element (15).

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