CN218096664U - Cascade compression refrigeration system and refrigeration device - Google Patents

Abstract

The utility model provides a cascade compression refrigerating system and refrigerating plant, refrigerating system includes high temperature level and low temperature level refrigeration cycle return circuit, high temperature level refrigeration cycle return circuit includes high temperature level compressor, the diverter valve, parallelly connected branch road, the high temperature level evaporimeter and the high temperature level muffler of connecting high temperature level evaporimeter and high temperature level compressor, parallelly connected branch road is including parallelly connected first and second cooling branch road that sets up, first cooling branch road includes first throttling arrangement, second cooling branch road is including the second throttling arrangement and the evaporation portion of series connection setting, parallelly connected branch road still includes the third throttling arrangement parallelly connected with second throttling arrangement, first refrigerant flowing through in first, second throttling arrangement respectively with flow through the first refrigerant heat transfer in the high temperature level muffler; the low-temperature-stage refrigeration cycle loop comprises a condensation part, and a second refrigerant flowing through the condensation part exchanges heat with a first refrigerant flowing through the evaporation part so as to solve the problems of large starting pressure and low refrigeration efficiency when the low-temperature-stage compressor is started.

Description

Cascade compression refrigeration system and refrigeration device

Technical Field

The utility model relates to a refrigeration plant technical field especially relates to a cascade compression refrigerating system, refrigerating plant who has it.

Background

Along with the development of economy, the living standard of residents is greatly improved, the living idea is changed continuously, the living idea of health, nutrition and balanced matching is pursued, meanwhile, the diversified diet is pursued, the types of food materials and food are enriched, but the requirements of different food materials on the storage temperature are different, so that the requirements on a refrigerating device are higher, and different temperature areas need to be configured.

The refrigerating device in the current market usually refrigerates through a cascade compression refrigerating system so as to enable different storage compartments to have different temperature areas, however, the starting pressure of the low-temperature-stage compressor is large and the refrigerating efficiency is low when the low-temperature-stage compressor is started in the using process of the refrigerating device.

Disclosure of Invention

In order to solve the technical problem, an object of the present invention is to provide a cascade compression refrigeration system, a refrigeration device having the same, so as to solve the problem that the starting pressure is large and the refrigeration efficiency is low when the low-temperature stage compressor is started in the use process of the existing refrigeration device.

In order to achieve one of the above objects, one embodiment of the present invention provides a cascade compression refrigeration system, which comprises,

the high-temperature stage refrigeration cycle loop comprises a high-temperature stage compressor, a parallel branch, a switching valve arranged at an inlet of the parallel branch, a high-temperature stage evaporator and a high-temperature stage air return pipe connected with the high-temperature stage evaporator and the high-temperature stage compressor, wherein a first refrigerant flows in the high-temperature stage refrigeration cycle loop, the parallel branch comprises a first cooling branch and a second cooling branch which are arranged in parallel, the first cooling branch comprises a first throttling device, the second cooling branch comprises a second throttling device and an evaporation part which are arranged in series, the parallel branch further comprises a third throttling device arranged in parallel with the second throttling device, the first refrigerant flowing through the first throttling device and the first refrigerant flowing through the second throttling device exchange heat with the first refrigerant flowing through the high-temperature stage air return pipe respectively, and the switching valve is selectively communicated with at least one of the first cooling branch, the second throttling device and the third throttling device;

and the low-temperature stage refrigeration circulation loop comprises a low-temperature stage compressor and a condensation part, wherein a second refrigerant flows in the low-temperature stage refrigeration circulation loop, and the second refrigerant flowing through the condensation part exchanges heat with the first refrigerant flowing through the evaporation part.

As an embodiment of the present invention, the low-temperature stage refrigeration cycle circuit further includes a low-temperature stage throttling device, a low-temperature stage evaporator and a first air return pipe section, which are serially connected, and the condensation portion is disposed between the low-temperature stage compressor and the low-temperature stage throttling device.

As a further improvement of an embodiment of the present invention, the second refrigerant flowing through the first return-air pipe section exchanges heat with the second refrigerant flowing through the low-temperature stage throttling device.

As a further improvement of an embodiment of the present invention, the low-temperature stage refrigeration cycle loop further includes a second air return pipe section and a heat release pipe section, the second air return pipe section is located the low-temperature stage evaporator with between the low-temperature stage compressor, the heat release pipe section is located the low-temperature stage compressor with between the condensation portion, flow through the second refrigerant in the second air return pipe section and flow through the second refrigerant heat exchange in the heat release pipe section.

As a further improvement of an embodiment of the present invention, the second return air pipe section is located between the first return air pipe section and the low temperature stage compressor.

As a further improvement of an embodiment of the present invention, the second return air pipe section and the heat release pipe section are sleeved or attached to each other.

As a further improvement of an embodiment of the present invention, the low-temperature throttling device is a capillary tube, and the first return air pipe section is sleeved with or attached to the low-temperature throttling device.

As a further improvement of an embodiment of the present invention, the first throttling device and the second throttling device are respectively sleeved or attached to the high-temperature-level air return pipe.

In order to realize one of the above objects of the present invention, an embodiment of the present invention further provides a refrigeration device, which comprises a box body and further comprises the above-mentioned overlapping type compression refrigeration system, the box body is provided with a first storage chamber and a second storage chamber, the high temperature refrigeration cycle loop is the cooling of the first storage chamber, and the low temperature refrigeration cycle loop is the cooling of the second storage chamber.

As a further improvement of an embodiment of the present invention, the refrigeration apparatus further includes a controller, the controller is connected to the switching valve, and is configured to: and controlling the communication state of the switching valve, the first cold supply branch, the second throttling device and the third throttling device according to the temperature of the first storage chamber and the second storage chamber.

Compared with the prior art, the utility model discloses following beneficial effect has: the utility model discloses a cascade compression refrigerating system, refrigerating plant who has it, when first refrigerant circulates in first confession cold branch road, if first refrigerant flows out the evaporation department in the high-temperature stage refrigeration cycle return circuit from second throttling arrangement, through the second refrigerant that flows through the condensation portion and the first refrigerant heat transfer that flows through the evaporation portion, the heat of the second refrigerant that flows through the condensation portion can be absorbed to first refrigerant in the evaporation portion, thereby can further reduce the temperature of the second refrigerant in the condensation portion, for low-temperature stage refrigeration cycle return circuit precooling, thereby make low-temperature stage refrigeration cycle return circuit can realize lower temperature; meanwhile, the first refrigerant flowing through the first throttling device and the first refrigerant flowing through the second throttling device exchange heat with the first refrigerant flowing through the high-temperature-stage gas return pipe respectively, so that the first refrigerant in the high-temperature-stage gas return pipe can be utilized to cool the first refrigerant in the first throttling device and the first refrigerant in the second throttling device, the refrigerating capacity is increased, the suction temperature of the high-temperature-stage compressor is increased to about the ambient temperature, the refrigerating efficiency of the high-temperature-stage compressor is improved, and the working efficiency of the high-temperature-stage refrigerating circulation loop is improved; when the low-temperature stage compressor is started, the first refrigerant can circulate in the third throttling device, so that the problem of high starting pressure at the moment of starting the low-temperature stage compressor can be solved.

Drawings

Fig. 1 is a schematic structural diagram of a cascade compression refrigeration system according to an embodiment of the present invention.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments shown in the accompanying drawings.

In the various drawings of the present invention, certain dimensions of structures or portions may be exaggerated relative to other structures or portions for ease of illustration, and thus, are used only to illustrate the basic structure of the subject matter of the present invention.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements or structures, these described elements should not be limited by these terms. These terms are only used to distinguish these descriptive objects from one another.

An embodiment of the utility model provides a refrigerating plant, including the box and the door body, have the storing room in the box, the door body is used for opening or closes the storing room, and refrigerating plant still includes refrigerating system, and refrigerating system locates in the box and to the storing room cooling. Specifically, the refrigerating device can be set as a refrigerator, a freezer, or the like, so as to meet the requirements of different users and different application scenarios.

In this embodiment, the box body has a first storage chamber and a second storage chamber, the first storage chamber may be a refrigerating chamber or a freezing chamber, and the second storage chamber may be a temperature-changing chamber or a deep-cooling chamber. The refrigerating system adopts a cascade compression refrigerating system 100, and specifically comprises a high-temperature-stage refrigerating circulation loop 1 and a low-temperature-stage refrigerating circulation loop 2.

For convenience of description, in the present embodiment, the high-temperature-stage refrigeration cycle 1 supplies cold to the first storage compartment, and the low-temperature-stage refrigeration cycle 2 supplies cold to the second storage compartment. Of course, the two may be interchanged.

Of course, in other embodiments, other storage compartments besides the first storage compartment and the second storage compartment may be provided according to actual needs.

Referring to fig. 1, a high-temperature stage refrigeration cycle circuit 1 includes a high-temperature stage compressor 11, a parallel branch, a high-temperature stage evaporator 15, and a high-temperature stage return pipe 13 connecting the high-temperature stage evaporator 15 and the high-temperature stage compressor 11, which are arranged in series, a first refrigerant flows through the high-temperature stage refrigeration cycle circuit 1, the parallel branch includes a first cooling branch and a second cooling branch, which are arranged in parallel, the first cooling branch includes a first throttling device 161, the second cooling branch includes a second throttling device 162 and an evaporation portion 12, which are arranged in series, the parallel branch further includes a third throttling device 163, which is arranged in parallel with the second throttling device 162, and the first refrigerant flowing through the first throttling device 161 and the first refrigerant flowing through the second throttling device 162 exchange heat with the first refrigerant flowing through the high-temperature stage return pipe 13, respectively. The high temperature stage refrigeration cycle circuit 1 further includes a switching valve 17 disposed at an inlet of the parallel branch, and the switching valve 17 is selectively communicated with at least one of the first cooling branch, the second throttling device 162 and the third throttling device 163, so as to selectively control a flow direction of the first refrigerant as required, thereby implementing different functions and cooling effects. Thus, the first storage chamber can realize the temperature range of-30 to 10 ℃.

The low-temperature-stage refrigeration cycle circuit 2 includes a condensation unit 21, and a second refrigerant flows through the low-temperature-stage refrigeration cycle circuit 2, and the second refrigerant flowing through the condensation unit 21 exchanges heat with the first refrigerant flowing through the evaporation unit 12.

Thus, when the first refrigerant circulates in the first cooling branch, the high-temperature-stage evaporator 15 supplies cooling to the first storage compartment; when the first refrigerant flows through the second cooling branch, the first refrigerant flows out of the second throttling device 162 to the evaporation part 12 in the high-temperature-stage refrigeration cycle circuit 1, and the first refrigerant in the evaporation part 12 can absorb heat of the second refrigerant flowing through the condensation part 21 by heat exchange between the second refrigerant flowing through the condensation part 21 and the first refrigerant flowing through the evaporation part 12, so that the temperature of the second refrigerant in the condensation part 21 can be further reduced, and the second refrigerant is precooled for the low-temperature-stage refrigeration cycle circuit 2, so that the low-temperature-stage refrigeration cycle circuit 2 can achieve a lower temperature; meanwhile, as the first refrigerant flowing through the first throttling device 161 and the first refrigerant flowing through the second throttling device 162 exchange heat with the first refrigerant flowing through the high-temperature-stage air return pipe 13, the first refrigerant in the high-temperature-stage air return pipe 13 can be utilized to cool the first refrigerant in the first throttling device 161 and the second throttling device 162, so as to increase the cooling capacity, and simultaneously improve the suction temperature of the high-temperature-stage compressor 11, so that the suction temperature is raised to about the ambient temperature, so that the cooling efficiency of the high-temperature-stage compressor 11 is improved, and the working efficiency of the high-temperature-stage refrigeration cycle loop 1 is improved; when the low-temperature stage compressor 22 is started, the first refrigerant can be circulated in the third throttling device 163, so that the problem of large starting pressure at the starting moment of the low-temperature stage compressor 22 can be solved, and as a result, the temperature of the first refrigerant in the evaporation part 12 is too high or even reaches dozens of degrees due to the large heat dissipation capacity of the condensation part 21 at the starting moment of the low-temperature stage compressor 22, when the first refrigerant flows into the high-temperature stage return pipe 13 to exchange heat with the second throttling device 162, the temperature of the first refrigerant in the second throttling device 162 is increased to reduce the flow rate of the first refrigerant, so that the evaporation part 12 cannot provide enough cold for the condensation part 21, and further the starting pressure of the low-temperature stage compressor 22 is large.

Preferably, the first throttling means 161, the second throttling means 162 and the third throttling means 163 are all capillary tubes.

The first throttling device 161 and the second throttling device 162 are respectively in thermal connection with the high-temperature-stage return air pipe 13 in a sleeved or attached mode, so that the heat exchange efficiency of the first refrigerant circulating in the first throttling device and the second throttling device can be improved, and the energy utilization rate is improved.

Further, the high-temperature-stage refrigeration cycle circuit 1 further includes a high-temperature-stage dry filter 18 disposed between the high-temperature-stage condenser 14 and the parallel branch, and a liquid storage pack 19 disposed between the evaporation-section high-temperature-stage evaporator 15 and the high-temperature-stage return air pipe 13.

The low-temperature stage refrigeration cycle loop 2 further comprises a low-temperature stage compressor 22, a low-temperature stage throttling device 23, a low-temperature stage evaporator 24 and a first gas return pipe section 25 which are arranged in series, and the condensing part 21 is arranged between the low-temperature stage compressor 22 and the low-temperature stage throttling device 23.

Further, the second refrigerant flowing through the first gas return section 25 exchanges heat with the second refrigerant flowing through the low temperature-stage throttling device 23. Therefore, the second refrigerant flowing through the first gas return pipe section 25 can absorb the heat of the second refrigerant flowing through the low-temperature stage throttling device 23, and the temperature of the second refrigerant flowing to the suction port of the low-temperature stage compressor 22 is increased, so that the suction temperature of the low-temperature stage compressor 22 is increased, the energy utilization rate of the low-temperature stage refrigeration cycle loop 2 is increased, and the energy efficiency of the whole refrigeration device is improved.

Preferably, the low-temperature-stage throttling device 23 is a capillary tube, and the first return air pipe section 25 and the low-temperature-stage throttling device 23 are sleeved or attached to each other, so that the heat exchange efficiency of the second refrigerant circulating between the first return air pipe section and the low-temperature-stage throttling device is improved, and the energy utilization rate is improved.

Further, the low-temperature stage refrigeration cycle circuit 2 further includes a second air return pipe section 26 and a heat release pipe section 27, the second air return pipe section 26 is disposed between the low-temperature stage evaporator 24 and the low-temperature stage compressor 22, the heat release pipe section 27 is disposed between the low-temperature stage compressor 22 and the condensing portion 21, and the second refrigerant flowing through the second air return pipe section 26 exchanges heat with the second refrigerant flowing through the heat release pipe section 27. Therefore, the second refrigerant flowing through the second air return pipe section 26 can absorb the heat of the second refrigerant flowing through the heat release pipe section 27, the air suction temperature of the low-temperature stage compressor 22 is increased, the cold quantity of the second refrigerant flowing from the heat release pipe section 27 to the condensation part 21 is reduced, the low-temperature stage refrigeration cycle loop 2 can achieve lower temperature, the temperature of the second storage compartment is adjustable within the temperature range of-60 to-20 ℃, the energy utilization rate of the low-temperature stage refrigeration cycle loop 2 is increased, and the energy efficiency of the whole refrigeration device is improved.

Preferably, the second gas return pipe section 26 is located between the first gas return pipe section 25 and the low-temperature stage compressor 22, so that the energy utilization rate of the low-temperature stage refrigeration cycle circuit 2 can be maximally improved.

The second return air pipe section 26 and the heat release pipe section 27 are sleeved or attached to each other, which is beneficial to improving the heat exchange efficiency of the second refrigerant circulating in the two, and improving the energy utilization rate.

Further, the low-temperature-stage refrigeration cycle circuit 2 further includes a low-temperature-stage radiating pipe 28 disposed between the low-temperature-stage compressor 22 and the radiating pipe section 27, and a low-temperature-stage dry filter 29 disposed between the condensing portion 21 and the low-temperature-stage throttling device 23. The second refrigerant flowing out of the low-temperature stage compressor 22 can be radiated by the low-temperature stage radiator pipe 28, so that the low-temperature stage refrigeration cycle circuit 2 can achieve a lower temperature; the second refrigerant flowing out of the condensing portion 21 may be dried and filtered by the low-temperature stage filter-drier 29.

The first refrigerant and the second refrigerant may be the same refrigerant or different refrigerants.

In addition, "high temperature" and "low temperature" in the "high temperature stage refrigeration cycle circuit 1" and the "low temperature stage refrigeration cycle circuit 2" are relative terms, and the evaporation temperature of the first refrigerant flowing through the high temperature stage refrigeration cycle circuit 1 is relatively higher than the evaporation temperature of the second refrigerant flowing through the low temperature stage refrigeration cycle circuit 2.

Further, the refrigeration device further comprises a controller, wherein the controller is connected with the switching valve 17 and is used for controlling the communication state of the switching valve 17, the first cooling branch, the second throttling device 162 and the third throttling device 163 according to the temperature of the first storage chamber and the temperature of the second storage chamber.

In particular, the controller is configured to,

if the switching valve 17 is in communication with only the first cooling branch and the high-temperature stage compressor 11 is in an operating state, the duration of the switching valve 17 in communication with only the first cooling branch is timed, within a preset time T1, if the temperature T in the first storage compartment is high ₁ Is reduced to the preset shutdown temperature T _{1 off} Then, the temperature T in the second storage room is judged ₂ Whether a first preset condition is met or not, wherein the first preset condition is as follows: at the moment T ₂ More than or equal to the preset starting temperature T of the second storage chamber _2-opening Or at this moment, the preset shutdown temperature T of the second storage compartment _{2 off} <T ₂ <T _2-opening And T before the moment ₂ Is always greater than T _{2 guan (a)} ；

If yes, judging T ₂ Whether it is higher than the preset temperature T ₀ ；

If so, the switching valve 17 is controlled to switch to only communicate with the third throttling means 163;

after the preset time t2, controlling the low-temperature stage compressor 22 to start;

after the preset time t3, the switching valve 17 is controlled to be switched to be communicated with only the second throttling device 162.

Like this, in refrigerating plant operation in-process, certainly high temperature level refrigeration cycle return circuit begins for first storing room refrigeration begins, in the time of predetermineeing t1, if indoor temperature in first storing room falls to its and predetermines shutdown temperature and when not needing the refrigeration, then right the temperature of second storing room is judged, in order to avoid the second storing room can not get the refrigeration for a long time and lead to its interior high temperature, is unfavorable for the fresh-keeping of the article of storing wherein. If the preset time T1 is up, the temperature T of the second storage chamber ₂ The first preset condition is met, namely the second storage chamber needs to be refrigerated, and the temperature T of the second storage chamber is ₂ Greater than a predetermined temperature T ₀ During the operation, the switching valve 17 is controlled to be communicated with the third throttling device 163 only, and the high-temperature stage compressor 11 is controlled to start, so that the problem of large starting pressure of the low-temperature stage compressor 22 at the moment of starting can be solved, because the first refrigerant in the third throttling device 163 does not exchange heat with the first refrigerant in the high-temperature stage return pipe 13, the reduction of the flow rate of the first refrigerant in the third throttling device 163 is avoided, the evaporation part 12 is ensured to provide sufficient cold for the condensation part 21, and the overlarge pressure of the low-temperature stage compressor 22 at the moment of starting is avoided. Further, after the preset time t2, the evaporation part 12 provides enough cooling capacity for the condensation part 21, at this time, the low-temperature stage compressor 22 is started, and the low-temperature stage refrigeration cycle loop 2 supplies cooling capacity for the second storage compartment. After a preset time t3, the low-temperature stage compressor 22 operates stably, the switching valve 17 is controlled to be switched to be communicated with the second throttling device 162 only, the first refrigerant flowing through the second throttling device 162 exchanges heat with the first refrigerant flowing through the high-temperature stage air return pipe 13, and therefore the first refrigerant in the high-temperature stage air return pipe 13 can be used for cooling the first refrigerant in the second throttling device 162, the refrigerating capacity is increased, and meanwhile the high-temperature stage compression is improvedThe air suction temperature of the compressor 11 is raised to about the ambient temperature, the refrigeration efficiency of the high-temperature stage compressor 11 is improved, the cooling capacity supplied by the evaporation part 12 to the condensation part 21 is further improved, the refrigeration efficiency of the low-temperature stage refrigeration cycle loop 2 is improved, and the energy utilization rate of the refrigeration device is improved.

Preferably, T ₀ = 30-5 ℃, thereby avoiding the actual temperature T of the second storage chamber ₂ When the temperature is too high, the start pressure of the low-temperature stage compressor 22 becomes high.

Preferably, t1= 5-20 min, not only the high-temperature-stage refrigeration cycle loop 1 can provide enough cold for the first storage compartment, but also the second storage compartment is prevented from being unable to supply cold for a long time.

Preferably, t2 is less than or equal to 5min to ensure that the evaporator 12 provides enough cold for the condenser 21 to avoid excessive starting pressure at the low temperature stage compressor 22.

Preferably, t3= 0.5-10 min, and by this time, the pressure of the low-temperature-stage compressor 22 tends to be stable, and the improvement of the refrigeration efficiency of the low-temperature-stage refrigeration cycle loop 2 is facilitated, so that the temperature in the first storage compartment reaches the preset temperature as soon as possible, and the starting efficiency is improved.

Further, the controller is also configured to,

if T ₂ ≤T ₀ Then the control switch valve 17 is switched to communicate with only the second throttling device 162;

and after the preset time t2, controlling the low-temperature stage compressor 22 to start.

When the second storage chamber needs to be refrigerated and the temperature T of the second storage chamber is in the running state of the refrigerating device ₂ Not higher than a preset temperature T ₀ When the refrigerator is used, the second throttling device 162 can be directly used for cooling the evaporation part 12 to the condensation part 21, so that the first refrigerant flowing through the second throttling device 162 exchanges heat with the first refrigerant flowing through the high-temperature-level air return pipe 13, the cooling capacity of the evaporation part 12 to the condensation part 21 can be improved, the precooling efficiency is accelerated, and the refrigerating efficiency of the second storage compartment is improved.

Further, the controller is also configured to,

if T ₂ And if the first preset condition is not met, the high-temperature stage compressor 11 is controlled to stop.

That is, within the preset time T1, if the temperature of the first storage chamber is reduced to the preset shutdown temperature T _{1 off} And the temperature of the second storage chamber also reaches the preset shutdown temperature T _{2 off} Or the shutdown condition of the second storage compartment is met, the high-temperature stage compressor 11 can be stopped, so that energy consumption is saved.

Further, the controller is also configured to,

if the switching valve 17 is only communicated with the first cooling branch and the high-temperature stage compressor 11 is in the running state, timing the duration of the switching valve 17 in the state of being only communicated with the first cooling branch, and after a preset time T1, if the temperature T in the first storage compartment is up to T ₁ Has not yet fallen to the preset shutdown temperature T _{1 off} Or below, judging the temperature T in the second storage room ₂ Whether a second preset condition is met or not, wherein the second preset condition is as follows: at the moment T ₂ ≥T _2-opening Or, alternatively, T _{2 off} <T ₂ <T _2-opening And T1 is within T ₂ Is always greater than T _{2 guan (a)} ；

If yes, judging T ₂ Whether it is higher than the preset temperature T ₀ ；

If so, the switching valve 17 is controlled to switch to only communicate with the third throttling means 163;

after the preset time t2, controlling the low-temperature stage compressor 22 to start;

after the preset time t3, the control switch valve 17 is switched to be communicated with only the second throttling device 162.

Therefore, in the operation process of the refrigerating device, the high-temperature refrigeration circulation loop starts to refrigerate the first storage chamber, after the preset time t1, if the temperature in the first storage chamber is not reduced to the preset shutdown temperature, whether the second storage chamber needs to refrigerate or not is judged firstly, so that the situation that the temperature in the second storage chamber is too high due to the fact that the second storage chamber cannot refrigerate for a long time and the temperature in the second storage chamber is not favorable for protecting articles stored in the second storage chamber is avoidedFresh. If the preset time T1 is passed, the second storage chamber needs to be refrigerated, and the temperature T of the second storage chamber is ₂ Greater than a predetermined temperature T ₀ The switching valve 17 is controlled to be communicated with the third throttling device 163 only, and the high-temperature stage compressor 11 is controlled to be started, so that the problem of large starting pressure at the moment of starting the low-temperature stage compressor 22 can be solved, and because the first refrigerant in the third throttling device 163 does not exchange heat with the first refrigerant in the high-temperature stage air return pipe 13, the reduction of the flow rate of the first refrigerant in the third throttling device 163 is avoided, the evaporation part 12 is ensured to provide enough cold for the condensation part 21, and the overlarge pressure at the moment of starting the low-temperature stage compressor 22 is avoided. Further, after the preset time t2, the evaporation part 12 provides enough cooling capacity for the condensation part 21, at this time, the low-temperature stage compressor 22 is started, and the low-temperature stage refrigeration cycle loop 2 supplies cooling capacity for the second storage compartment. After a preset time t3, the low-temperature stage compressor 22 operates stably, the switching valve 17 is controlled to be switched to be only communicated with the second throttling device 162, the first refrigerant flowing through the second throttling device 162 exchanges heat with the first refrigerant flowing through the high-temperature stage return pipe 13, so that the first refrigerant in the high-temperature stage return pipe 13 can be used for cooling the first refrigerant in the second throttling device 162, the cooling capacity is increased, the suction temperature of the high-temperature stage compressor 11 is increased to about the ambient temperature, the cooling efficiency of the high-temperature stage compressor 11 is improved, the cooling capacity of the evaporation part 12 to the condensation part 21 is further improved, the cooling efficiency of the low-temperature stage refrigeration cycle loop 2 is improved, and the energy utilization rate of the cooling device is improved.

Further, the controller is further configured to:

if T ₂ ≤T ₀ Then the control switch valve 17 is switched to communicate with only the second throttling device 162;

and after the preset time t2, controlling the low-temperature stage compressor 22 to start.

When the second storage chamber needs to refrigerate and the temperature T of the second storage chamber is in the running state of the refrigerating device ₂ Not higher than a preset temperature T ₀ In this case, the refrigerant may be directly supplied from the evaporation unit 12 to the condensation unit 21 through the second throttling device 162, and then may be passed through the second throttling deviceThe first refrigerant in the throttling device 162 exchanges heat with the first refrigerant flowing through the high-temperature-stage air return pipe 13, so that the cooling capacity of the evaporation part 12 to the condensation part 21 can be improved, the precooling efficiency is increased, and the refrigerating efficiency of the second storage chamber is improved.

Further, the controller is further configured to:

if T is ₂ If the second preset condition is not met, the duration of the switching valve 17 in the state of communication only with the first cooling branch is counted again.

That is, after the preset time T1, if the temperature of the first storage chamber has not decreased to the preset shutdown temperature T thereof yet _{1 off} And the temperature of the second storage chamber is reduced to the preset shutdown temperature T _{2 off} Or the shutdown condition of the second storage compartment is met, the high-temperature-stage compressor 11 needs to continue to operate at the moment, and for cooling the first storage compartment, a new round of temperature monitoring and compressor operation state control are performed by timing the duration of the switching valve 17 in the state of being only communicated with the first cooling branch again.

The utility model also provides a control method of the refrigerating device, which comprises the following steps,

if the switching valve 17 is in communication with only the first cooling branch and the high-temperature stage compressor 11 is in an operating state, the duration of the switching valve 17 in communication with only the first cooling branch is timed, within a preset time T1, if the temperature T in the first storage compartment is high ₁ Is reduced to the preset shutdown temperature T _{1 off} Then, the temperature T in the second storage room is judged ₂ Whether a first preset condition is met or not, wherein the first preset condition is as follows: at this time T ₂ More than or equal to the preset starting temperature T of the second storage chamber _2-opening Or at this moment, the preset shutdown temperature T of the second storage compartment _{2 off} <T ₂ <T _{2 open} And before the time T ₂ Is always greater than T _{2 off} ；

If yes, judging T ₂ Whether it is higher than the preset temperature T ₀ ；

If so, the switching valve 17 is controlled to switch to only communicate with the third throttling means 163;

after the preset time t2, controlling the low-temperature stage compressor 22 to start;

after the preset time t3, the switching valve 17 is controlled to be switched to be communicated with only the second throttling device 162.

Like this, in refrigerating plant operation in-process, certainly high temperature level refrigeration cycle return circuit begins to give room refrigeration begins between first storing, in the time of predetermineeing t1, if indoor temperature falls to its shutdown temperature of predetermineeing and when not needing to refrigerate between first storing, then right the temperature of room is judged between the second storing, in order to avoid room is not refrigerated for a long time between the second storing and leads to its interior high temperature, is unfavorable for storing the fresh-keeping of article wherein. If the preset time T1 is within, the temperature T of the second storage chamber ₂ The first preset condition is met, namely the second storage chamber needs to be refrigerated, and the temperature T of the second storage chamber is ₂ Greater than a predetermined temperature T ₀ During the process, the switching valve 17 is controlled to be communicated with the third throttling device 163 only, and the high-temperature stage compressor 11 is controlled to be started, so that the problem of large starting pressure at the moment of starting the low-temperature stage compressor 22 can be solved, and because the first refrigerant in the third throttling device 163 does not exchange heat with the first refrigerant in the high-temperature stage return air pipe 13, the reduction of the flow rate of the first refrigerant in the third throttling device 163 is avoided, the evaporation part 12 is ensured to provide sufficient cold for the condensation part 21, and the overlarge pressure at the moment of starting the low-temperature stage compressor 22 is avoided. Further, after the preset time t2, the evaporation part 12 provides enough cold energy for the condensation part 21, at this time, the low-temperature stage compressor 22 is started, and the low-temperature stage refrigeration cycle loop 2 supplies cold for the second storage compartment. After a preset time t3, the low-temperature stage compressor 22 operates stably, the switching valve 17 is controlled to be switched to be only communicated with the second throttling device 162, the first refrigerant flowing through the second throttling device 162 exchanges heat with the first refrigerant flowing through the high-temperature stage return air pipe 13, so that the first refrigerant in the high-temperature stage return air pipe 13 can be used for cooling the first refrigerant in the second throttling device 162, the refrigerating capacity is increased, and meanwhile, the air suction of the high-temperature stage compressor 11 is improvedThe temperature is raised to about the ambient temperature, so that the refrigeration efficiency of the high-temperature stage compressor 11 is improved, the cooling capacity of the evaporation part 12 to the condensation part 21 is further improved, the refrigeration efficiency of the low-temperature stage refrigeration circulation loop 2 is improved, and the energy utilization rate of the refrigeration device is improved.

Preferably, T ₀ = 30-5 ℃, thereby avoiding the actual temperature T of the second storage chamber ₂ When the temperature is too high, the start pressure of the low-temperature stage compressor 22 becomes high.

Preferably, t1= 5-20 min, not only the high-temperature-stage refrigeration cycle loop 1 can provide enough cold for the first storage compartment, but also the second storage compartment is prevented from being unable to supply cold for a long time.

Preferably, t2 is less than or equal to 5min to ensure that the evaporator 12 provides enough cold for the condenser 21 to avoid excessive starting pressure at the low temperature stage compressor 22.

Preferably, t3= 0.5-10 min, and by this period of time, the pressure of the low-temperature-stage compressor 22 tends to be stable, and the improvement of the refrigeration efficiency of the low-temperature-stage refrigeration cycle loop 2 is facilitated, so that the temperature in the first storage compartment reaches the preset temperature as soon as possible, and the starting efficiency is improved.

Further, the control method may further include,

if T is ₂ ≤T ₀ Then the control switch valve 17 is switched to communicate with only the second throttling device 162;

and after the preset time t2, controlling the low-temperature stage compressor 22 to start.

When the second storage chamber needs to be refrigerated and the temperature T of the second storage chamber is in the running state of the refrigerating device ₂ Not higher than a predetermined temperature T ₀ When the refrigerator is used, the second throttling device 162 can be directly used for cooling the evaporation part 12 to the condensation part 21, so that the first refrigerant flowing through the second throttling device 162 exchanges heat with the first refrigerant flowing through the high-temperature-level air return pipe 13, the cooling capacity of the evaporation part 12 to the condensation part 21 can be improved, the precooling efficiency is accelerated, and the refrigerating efficiency of the second storage compartment is improved.

Further, the control method may further include,

if T is ₂ And if the first preset condition is not met, the high-temperature stage compressor 11 is controlled to stop.

That is to say, within the preset time T1, if the temperature of the first storage chamber is reduced to the preset shutdown temperature T _{1 off} And the temperature of the second storage chamber also reaches the preset shutdown temperature T _{2 off} Or the shutdown condition of the second storage compartment is met, the high-temperature stage compressor 11 can be stopped, so that energy consumption is saved.

Further, the control method may further include,

if the switching valve 17 is only communicated with the first cooling branch and the high-temperature stage compressor 11 is in the running state, timing the duration of the switching valve 17 in the state of being only communicated with the first cooling branch, and after a preset time T1, if the temperature T in the first storage compartment is up to T ₁ Has not yet decreased to the preset shutdown temperature T _{1 off} Or below, judging the temperature T in the second storage room ₂ Whether a second preset condition is met or not, wherein the second preset condition is as follows: at this time T ₂ ≥T _2-opening Or, alternatively, T _{2 off} <T ₂ <T _2-opening And T1 is within T ₂ Is always greater than T _{2 guan (a)} ；

If yes, judging T ₂ Whether it is higher than the preset temperature T ₀ ；

If so, the switching valve 17 is controlled to switch to only communicate with the third throttling means 163;

after the preset time t2, controlling the low-temperature stage compressor 22 to start;

after the preset time t3, the switching valve 17 is controlled to be switched to be communicated with only the second throttling device 162.

Therefore, in the operation process of the refrigerating device, the high-temperature refrigeration circulation loop starts to refrigerate the first storage room, after the preset time t1, if the temperature in the first storage room is not reduced to the preset shutdown temperature, whether the second storage room needs to refrigerate or not is judged firstly, so that the situation that the temperature in the second storage room is too high due to the fact that the second storage room cannot refrigerate for a long time and the temperature in the second storage room is not favorable for protecting articles stored in the second storage room is avoidedFresh. If the preset time T1 is passed, the second storage chamber needs to be refrigerated, and the temperature T of the second storage chamber is ₂ Greater than a predetermined temperature T ₀ During the process, the switching valve 17 is controlled to be communicated with the third throttling device 163 only, and the high-temperature stage compressor 11 is controlled to be started, so that the problem of large starting pressure at the moment of starting the low-temperature stage compressor 22 can be solved, and because the first refrigerant in the third throttling device 163 does not exchange heat with the first refrigerant in the high-temperature stage return air pipe 13, the reduction of the flow rate of the first refrigerant in the third throttling device 163 is avoided, the evaporation part 12 is ensured to provide sufficient cold for the condensation part 21, and the overlarge pressure at the moment of starting the low-temperature stage compressor 22 is avoided. Further, after the preset time t2, the evaporation part 12 provides enough cooling capacity for the condensation part 21, at this time, the low-temperature stage compressor 22 is started, and the low-temperature stage refrigeration cycle loop 2 supplies cooling capacity for the second storage compartment. After a preset time t3, the low-temperature stage compressor 22 operates stably, the switching valve 17 is controlled to be switched to be only communicated with the second throttling device 162, the first refrigerant flowing through the second throttling device 162 exchanges heat with the first refrigerant flowing through the high-temperature stage return pipe 13, so that the first refrigerant in the high-temperature stage return pipe 13 can be used for cooling the first refrigerant in the second throttling device 162, the cooling capacity is increased, the suction temperature of the high-temperature stage compressor 11 is increased to about the ambient temperature, the cooling efficiency of the high-temperature stage compressor 11 is improved, the cooling capacity of the evaporation part 12 to the condensation part 21 is further improved, the cooling efficiency of the low-temperature stage refrigeration cycle loop 2 is improved, and the energy utilization rate of the cooling device is improved.

Further, the control method further includes:

if T ₂ ≤T ₀ Then the control switch valve 17 is switched to communicate with only the second throttling device 162;

and after the preset time t2, controlling the low-temperature stage compressor 22 to start.

When the second storage chamber needs to be refrigerated and the temperature T of the second storage chamber is in the running state of the refrigerating device ₂ Not higher than a predetermined temperature T ₀ In this case, the refrigerant may be directly supplied from the evaporation unit 12 to the condensation unit 21 through the second throttle device 162 and then may flow through the second throttle deviceThe first refrigerant in the second throttling device 162 exchanges heat with the first refrigerant flowing through the high-temperature-stage air return pipe 13, so that the cooling capacity of the evaporation part 12 to the condensation part 21 can be improved, the precooling efficiency is increased, and the refrigerating efficiency of the second storage chamber is improved.

Further, the control method further includes:

if T is ₂ If the second preset condition is not met, the duration of the switching valve 17 in the state of communication only with the first cooling branch is counted again.

Then the above steps are circulated, that is, within the preset time T1, if T ₁ Down to T _{1 off} Then, determine T ₂ And whether the first preset condition is met or not, and executing the subsequent steps.

That is to say, after the preset time T1, if the temperature of the first storage chamber is not reduced to the preset shutdown temperature T yet _{1 off} And the temperature of the second storage chamber is reduced to the preset shutdown temperature T _{2 off} Or the shutdown condition of the second storage compartment is met, the high-temperature-stage compressor 11 needs to continue to operate at the moment, the first storage compartment is cooled, the duration of the state that the switching valve 17 is only communicated with the first cooling branch is counted again, and a new round of temperature monitoring and compressor operation state control are carried out.

Compared with the prior art, the utility model provides a cascade compression refrigerating system 100, refrigerating plant and refrigerating plant's that has it control method, its beneficial effect lies in: the switching valve 17 selectively controls the flow direction of the first refrigerant as required to realize different functions and refrigeration effects; when the first refrigerant circulates in the first cooling branch, the high-temperature-stage evaporator 15 supplies cooling to the first storage compartment; when the first refrigerant flows through the second cooling branch, if the first refrigerant flows out of the second throttling device 162 to the evaporation portion 12 in the high-temperature-stage refrigeration cycle circuit 1, the second refrigerant flowing through the condensation portion 21 exchanges heat with the first refrigerant flowing through the evaporation portion 12, and the first refrigerant in the evaporation portion 12 can absorb heat of the second refrigerant flowing through the condensation portion 21, so that the temperature of the second refrigerant in the condensation portion 21 can be further reduced, and the second refrigerant is precooled for the low-temperature-stage refrigeration cycle circuit 2, so that the low-temperature-stage refrigeration cycle circuit 2 can achieve a lower temperature; meanwhile, as the first refrigerant flowing through the first throttling device 161 and the first refrigerant flowing through the second throttling device 162 exchange heat with the first refrigerant flowing through the high-temperature-stage air return pipe 13, the first refrigerant in the high-temperature-stage air return pipe 13 can be utilized to cool the first refrigerant in the first throttling device 161 and the second throttling device 162, so as to increase the cooling capacity, and simultaneously improve the suction temperature of the high-temperature-stage compressor 11, so that the suction temperature is raised to about the ambient temperature, so that the cooling efficiency of the high-temperature-stage compressor 11 is improved, and the working efficiency of the high-temperature-stage refrigeration cycle loop 1 is improved; when the low-temperature stage compressor 22 is started, the first refrigerant can be circulated in the third throttling device 163, so that the problem of large starting pressure at the starting moment of the low-temperature stage compressor 22 can be solved, and as a result, the temperature of the first refrigerant in the evaporation part 12 is too high or even reaches dozens of degrees due to the large heat dissipation capacity of the condensation part 21 at the starting moment of the low-temperature stage compressor 22, when the first refrigerant flows into the high-temperature stage return pipe 13 to exchange heat with the second throttling device 162, the temperature of the first refrigerant in the second throttling device 162 is increased to reduce the flow rate of the first refrigerant, so that the evaporation part 12 cannot provide enough cold for the condensation part 21, and further the starting pressure of the low-temperature stage compressor 22 is large.

It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.

The above list of details is only for the practical implementation of the present invention, and they are not intended to limit the scope of the present invention, and all equivalent implementations or modifications that do not depart from the technical spirit of the present invention should be included in the scope of the present invention.

Claims (10)

1. A cascade compression refrigeration system, comprising,

the high-temperature stage refrigeration cycle loop comprises a high-temperature stage compressor, a parallel branch, a switching valve arranged at an inlet of the parallel branch, a high-temperature stage evaporator and a high-temperature stage air return pipe connected with the high-temperature stage evaporator and the high-temperature stage compressor, wherein a first refrigerant flows in the high-temperature stage refrigeration cycle loop, the parallel branch comprises a first cooling branch and a second cooling branch which are arranged in parallel, the first cooling branch comprises a first throttling device, the second cooling branch comprises a second throttling device and an evaporation part which are arranged in series, the parallel branch further comprises a third throttling device arranged in parallel with the second throttling device, the first refrigerant flowing through the first throttling device and the first refrigerant flowing through the second throttling device exchange heat with the first refrigerant flowing through the high-temperature stage air return pipe respectively, and the switching valve is selectively communicated with at least one of the first cooling branch, the second throttling device and the third throttling device;

and the low-temperature stage refrigeration circulation loop comprises a low-temperature stage compressor and a condensation part, wherein a second refrigerant flows in the low-temperature stage refrigeration circulation loop, and the second refrigerant flowing through the condensation part exchanges heat with the first refrigerant flowing through the evaporation part.

2. The cascade compression refrigeration system according to claim 1, wherein the low temperature stage refrigeration cycle further comprises a low temperature stage throttling device, a low temperature stage evaporator and a first return air pipe section arranged in series, and the condensing portion is arranged between the low temperature stage compressor and the low temperature stage throttling device.

3. The cascade compression refrigeration system of claim 2, wherein the second refrigerant flowing through the first return gas tube segment exchanges heat with the second refrigerant flowing through the low temperature stage throttling device.

4. The cascade compression refrigeration system according to claim 2, wherein the low temperature stage refrigeration cycle further comprises a second return air pipe section and a heat release pipe section, the second return air pipe section is disposed between the low temperature stage evaporator and the low temperature stage compressor, the heat release pipe section is disposed between the low temperature stage compressor and the condensation portion, and the second refrigerant flowing through the second return air pipe section exchanges heat with the second refrigerant flowing through the heat release pipe section.

5. The cascade compression refrigeration system of claim 4, wherein the second return gas leg is located between the first return gas leg and the low temperature stage compressor.

6. The cascade compression refrigeration system according to claim 4, wherein the second return air duct segment is nested or abutted against the heat release duct segment.

7. The cascade compression refrigeration system according to claim 4, wherein the low temperature stage throttling device is a capillary tube, and the first return air tube section and the low temperature stage throttling device are sleeved or attached to each other.

8. The cascade compression refrigeration system according to claim 1, wherein said first throttling device and said second throttling device are respectively sleeved with or attached to said high temperature stage muffler.

9. A refrigerating device comprising a box body, wherein the box body further comprises the cascade compression refrigerating system as recited in any one of claims 1 to 8, the box body is provided with a first storage chamber and a second storage chamber, the high-temperature stage refrigerating circulation loop supplies cold to the first storage chamber, and the low-temperature stage refrigerating circulation loop supplies cold to the second storage chamber.

10. The refrigeration unit of claim 9, further comprising a controller coupled to the switching valve and configured to: and controlling the communication state of the switching valve, the first cold supply branch, the second throttling device and the third throttling device according to the temperature of the first storage chamber and the second storage chamber.

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