CN102109238B - Cooling device - Google Patents

Abstract

The invention provides a cooling device (R) which can improve the starting problem of a compressing mechanism and realize a stable and high-efficient operation, wherein a refrigerant circuit (1) is composed of a compressor (11), a gas cooler (46), a main throttle mechanism (62A, 62B), and an evaporator (63A, 63B), and has a supercritical pressure at a high-pressure side. The cooling device (R) comprises a bypass circuit (84) which communicates an intermediate-pressure region and a low-pressure side region of the refrigerant circuit (1); a solenoid valve (85) which is disposed in the bypass circuit; a control mechanism (C) which controls the solenoid valve (85) and opens the flow path of the bypass circuit (84) using the solenoid valve (85) from the starting of the compressor (11) till the operation frequency is increased to a defined value.

Description

Refrigerating plant

Technical field

The present invention relates to form by compressing mechanism, gas cooler, throttle mechanism and evaporimeter the refrigerating plant that refrigerant loop and high-pressure side become supercritical pressure.

Background technology

At present, in this refrigerating plant, form kind of refrigeration cycle by compressing mechanism, gas cooler, throttle mechanism etc., cold-producing medium after the compression of compressed mechanism dispels the heat by gas cooler and reduces pressure by throttle mechanism, pass through afterwards evaporator evaporation, thereby utilize the evaporation of cold-producing medium at that time to carry out cooling ambient air.In recent years, in this refrigerating plant, because natural environmental stress etc. can't be used the freon series coolant.Therefore, developed the carbon dioxide that the is used as natural refrigerant refrigerating plant as the substitute of freon refrigerant.Known this carbon dioxide coolant is height pressure reduction large cold-producing medium, and low and high-pressure side refrigerant circulation under the effect of compression of critical pressure becomes supercriticality.

Patent documentation 1: Japanese Patent Publication 7-18602 communique

In above-mentioned refrigerating plant, while usually turning round, the low normal condition that belongs to of pressure in the zone, pressure ratio high-pressure side (zone, high-pressure side from the second compressing member ejection of above-mentioned compressor structure) in the middle nip territory of refrigerant loop (the middle nip territory from the first compressing member ejection of the compressing mechanism for example, formed by the second-compressed element).With respect to this, when the starting compressor structure, if external temperature is low, can be from the high status triggering of pressure of the area of low pressure of refrigerant loop, thus cause the pressure in middle nip territory just to rise in early days.Now, because the cold-producing medium in the zone, high-pressure side of refrigerant loop is cooling by gas cooler, therefore can not form at once high temperature.Therefore, the pressure in the middle nip territory of refrigerant loop and the pressure of high-pressure area approach, thereby can not guarantee fully the pressure reduction of middle nip territory and high-pressure area, until the compressive state of cold-producing medium becomes the mal-compression state.

Thus, may produce following problem: cause the poor starting of compressing mechanism, the cooling capacity of refrigerating plant significantly reduces, and the increase of the power of compressing mechanism, the Efficiency Decreasing of kind of refrigeration cycle.

Summary of the invention

The present invention proposes for the problem that solves prior art, and its purpose is to provide a kind of refrigerating plant that improves the poor starting of compressing mechanism and can realize stable and high efficiency running.

In order to address the above problem, a first aspect of the present invention provides a kind of refrigerating plant, it by compressing mechanism, gas cooler, throttle mechanism, evaporimeter, forms refrigerant loop and high-pressure side becomes supercritical pressure, described refrigerating plant is characterised in that, it possesses: bypass circulation, and it is communicated with middle nip territory and the low-pressure side zone of refrigerant loop; Valve gear, it is arranged in this bypass circulation; Controlling organization, it controls this valve gear, and wherein, this controlling organization utilized valve gear to open the stream of bypass circulation before the operating frequency of compressing mechanism regulation from start to rising to.

On the basis of above-mentioned first aspect, a second aspect of the present invention is characterised in that, uses carbon dioxide as cold-producing medium.

The invention effect

In refrigerating plant of the present invention, form refrigerant loop and high-pressure side becomes supercritical pressure by compressing mechanism, gas cooler, throttle mechanism, evaporimeter, described refrigerating plant possesses: bypass circulation, and it is communicated with middle nip territory and the low-pressure side zone of refrigerant loop; Valve gear, it is arranged in this bypass circulation; Controlling organization, it controls this valve gear, wherein, this controlling organization utilized valve gear to open the stream of bypass circulation before the operating frequency of compressing mechanism regulation from start to rising to, make thus the cold-producing medium in the middle nip territory of refrigerant loop flow into the low-pressure side zone via bypass circulation, can make the pressure initiation in middle nip territory and low-pressure side zone all press.

The start-up period of the compressing mechanism before the operating frequency of compressing mechanism regulation from start to rising to, can't guarantee the torque of regulation, but by being formed all, middle nip territory and low-pressure side zone press during this period, even under the situation easily uprised because of the high and middle pressure-volume of extraneous gas temperature, the unfavorable condition of the nearly high pressure of crimping in the middle of also can eliminating.

Therefore, during compressing mechanism start-up period generation torque deficiency, can avoid in advance, because of the pressure in middle nip territory and the approaching poor starting caused of pressure of high-pressure area, can realizing stable and high efficiency running.

In addition, in the situation that used carbon dioxide as cold-producing medium, by foregoing invention, refrigerating capacity can be effectively improved as a second aspect of the present invention, the raising of performance can be realized.

The accompanying drawing explanation

Fig. 1 is the refrigerant loop figure of the present embodiment refrigerating plant.

Fig. 2 is the block diagram of control device.

Fig. 3 means the figure by the trend of extraneous gas temperature and the definite target high pressure HPT of evaporating temperature.

Fig. 4 is the local vertical profile side view of cold-producing medium adjuster.

Fig. 5 is the side elevation in partial section of cold-producing medium adjuster.

Symbol description:

The R refrigerating plant

C control device (controlling organization)

1 refrigerant loop

3 refrigerator units

5A, 5B showcase unit

7,9 refrigerant pipings

11 compressors

12 closed containers

14 electric elements

18 first rotary compression elements

20 second rotary compression elements

22 rudimentary side draught entrances

24 rudimentary side spray outlets

26 senior side draught entrances

28 senior side spray outlets

32 low-pressure sensors (suction pressure testing agency)

34 unit inlet temperature sensors (inlet temperature testing agency)

Press the ejection pipe arrangement in the middle of 36

38 intercoolers

42 high pressure ejection pipe arrangements

44 separators

45 wind paths

46 gas coolers

47 gas cooler air blasts

48 high-pressure sensors (high-pressure testing agency)

Pressure pressure sensors in the middle of 49 (middle pressure pressure testing agency)

50 ejection temperature sensors (ejection temperature testing organization)

52 gas cooler exit temperature sensors (gas cooler exit temperature testing agency)

54 unit outlet temperature sensors (unit outlet temperature testing agency)

56 extraneous gas temperature sensors (extraneous gas temperature testing organization)

58 unit outlet side pressure sensors (unit outlet side pressure detection mechanism)

60A, 60B cabinet side refrigerant piping

62A, 62B master's throttle mechanism

63A, 63B evaporimeter

64A, 64B communicating pipe

65A, 65B magnetic valve (valve gear, stream controlling organization)

66A, 66B magnetic valve (valve gear, stream controlling organization)

70 waste heat recovery heat exchangers

The 70A refrigerant flow path

70B current road

71 gas cooler bypass circulations

72 magnetic valves (valve gear)

73 oil return circuits

74 oil coolers

76 flow rate regulating valves (motor-driven valve)

78 oil bypass loops

79 magnetic valves (valve gear)

80 Intermediate Heat Exchangers

80A the first stream

80B the second stream

83 auxiliary expansion valves (auxiliary throttle mechanism)

84 bypass circulations

85 magnetic valves (valve gear)

86 oil return pipes

90 check-valves

91 cold-producing medium adjusters

92 closed containers

93 partition walls

100 refrigerant amount adjusting tanks

101 first connected loops

102 electric expansion valves (the first switching mechanism with throttling function)

103 second connected loops

104 magnetic valves (the second switching mechanism)

105 third connecting loops

106 magnetic valves (the 3rd switching mechanism)

The specific embodiment

Below, illustrate referring to the drawings embodiments of the present invention.Fig. 1 is the refrigerant loop figure of the refrigerating plant R of embodiments of the present invention.The refrigerating plant R of the present embodiment possesses refrigerator unit 3 and Duo Tai showcase unit 5A, 5B, and above-mentioned refrigerator unit 3 and each showcase unit 5A, 5B link by refrigerant piping 7 and 9 kind of refrigeration cycle that forms regulation.

In this kind of refrigeration cycle, use on high-tension side refrigerant pressure (high-pressure) to become the carbon dioxide of its critical pressure above (overcritical) as cold-producing medium.This carbon dioxide coolant is the natural refrigerant that is conducive to earth environment and has considered combustibility and toxicity etc.In addition, the oil as lubricating oil is used the existing oil such as mineral oil (Dormant oils), alkylbenzene oil, ether oil, ester oil, PAG (PAG).

Refrigerator unit 3 has two compressors 11,11 of configuration arranged side by side.In the present embodiment, compressor 11 is bosom die mould multi-stage compression formula rotary compressors, comprise the closed container cylindraceous 12 that formed by steel plate, configuration be accommodated in this closed container 12 inner space upside the electric element as driving element 14 and be configured in the downside of this electric element 14 and the section of rotary compression mechanism formed by first (rudimentary side) rotary compression element (the first compressing member) 18 and second (senior side) rotary compression element (the second compressing member) 20 that the rotating shaft 16 by electric element 14 drives.

The low pressure refrigerant that the first 18 pairs of rotary compression elements suck compressor 11 via refrigerant piping 9 from the low-pressure side of refrigerant loop 1 is compressed and it is pressed in the middle of boosting to and by its ejection, the second rotary compression element 20 further sucks and compress by the first rotary compression element 18 compressions ejection in the middle of the cold-producing medium of pressure, and make it boost to high pressure and spray to the high-pressure side of refrigerant loop 1.Compressor 11 is compressors of Variable frequency type frequency, can control the rotating speed of the first rotary compression element 18 and the second rotary compression element 20 by the operating frequency of change electric element 14.

Be formed with the rudimentary side draught entrance 22 and rudimentary side spray outlet 24, the senior side draught entrance 26 be communicated with the second rotary compression element 20 and the senior side spray that are communicated with the first rotary compression element 18 in the side of the closed container 12 of compressor 11 and export 28.Rudimentary side draught entrance 22,22 at each compressor 11,11 is connected with respectively cold-producing medium ingress pipe 30, and each cold-producing medium ingress pipe 30 collaborates and is connected with refrigerant piping 9 at their upstream side.

In the middle of being boosted to by this first rotary compression element 18, the refrigerant gas that sucks the low pressure (LP: 4MPa left and right under operating condition) usually of the low voltage section of the first rotary compression elements 18 by rudimentary side draught entrance 22 presses (MP: 8MPa left and right under operating condition) usually and to the interior ejection of closed container 12.Thus, become middle press (MP) in closed container 12.

Then, press ejection pipe arrangement 36,36 in the middle of the rudimentary side spray outlet 24,24 of each compressor 11,11 of the refrigerant gas of pressing in the middle of in ejection closed container 12 is connected with respectively, in the middle of each, press ejection pipe arrangement 36 to be connected with an end of intercooler 38 at their interflow, downstream.38 pairs of middle cold-producing mediums of pressing from the first rotary compression element 18 ejections of this intercooler carry out air cooling, press suction line 40 in the middle of the other end of this intercooler 38 is connected with, this centre pressure suction line 40 is divided into after two and is connected with the senior side draught entrance 26,26 of each compressor 11,11.

The refrigerant gas of middle pressure (MP) that sucks the middle splenium of the second rotary compression elements 20 by senior side draught entrance 26 is carried out by this second rotary compression element 20 refrigerant gas that second level compression becomes HTHP (HP: the supercritical pressure of 12MPa left and right under operating condition) usually.

And, senior side spray outlet 28,28 in the hyperbaric chamber side of the second rotary compression element 20 of being located at each compressor 11,11 is connected with respectively high pressure ejection pipe arrangement 42,42, each high pressure ejection pipe arrangement 42,42 interflow, the downstream at them, be connected with refrigerant loop 7 via the Intermediate Heat Exchanger 80 of separator 44, gas cooler 46, the waste heat recovery heat exchanger 70 be described in detail below and formation separating cycle.

46 pairs of ejection cold-producing mediums from the high pressure of compressor 11 ejections of gas cooler carry out cooling, are provided with the air blast 47 for gas cooler that this gas cooler 46 is carried out to air cooling near gas cooler 46.In the present embodiment, gas cooler 46 is set up in parallel with above-mentioned intercooler 38 and the oil cooler 74 be described in detail below, and all is provided in same wind path 45.Be provided with the extraneous gas temperature sensor (extraneous gas temperature testing organization) 56 that detects the extraneous gas temperature that sets this refrigerator unit 3 in this wind path 45.

In addition, be provided with in senior side spray outlet 28,28 the high-pressure sensor (high-pressure testing agency) 48 that detects from the ejection pressure of the cold-producing medium of the second rotary compression element 20,20 ejections, detect the ejection temperature sensor (ejection temperature testing organization) 50 of ejection refrigerant temperature and possess the cold-producing medium adjuster 91 that to take from senior side spray outlet 28 directions towards gas cooler 46 (oil eliminator 44) of compressor 11 be check-valves 90 forward.In addition, this cold-producing medium adjuster 91 is described in detail below.

On the other hand, showcase unit 5A, 5B are separately positioned in shop etc., with refrigerant piping 7 and 9, are connected side by side respectively.Each showcase unit 5A, 5B have cabinet side refrigerant piping 60A, the 60B that links refrigerant piping 7 and refrigerant piping 9, on each cabinet side refrigerant piping 60A, 60B, are connected with respectively filter 61A, 61B, main throttle mechanism 62A, 62B, evaporimeter 63A, 63B in turn.On each evaporimeter 63A, 63B, adjacency has the not shown circulating cold air air blast to this evaporimeter air blast respectively.And this refrigerant piping 9 is connected with the rudimentary side draught entrance 22 be communicated with the first rotary compression element 18 of each compressor 11,11 via cold-producing medium ingress pipe 30 as mentioned above.Thus, form the refrigerant loop 1 of the refrigerating plant R of the present embodiment.

Refrigerating plant R possesses control device (controlling organization) C consisted of general microcomputer.This control device C as shown in Figure 2, is connected with various sensors at input side, and is connected with various valve gears, compressor 11,11, gas cooler with the fan motor 47M of air blast 47 etc. at outlet side.In addition, for the details of this control device C, correspondence is respectively controlled follow-up narration.

(A) the refrigerant amount adjustment is controlled

Next, the refrigerant amount adjustment of the refrigerant loop 1 of the refrigerating plant R of the present embodiment is controlled and described.In the high-pressure side that becomes supercritical pressure of refrigerant loop 1, in the downstream of the Intermediate Heat Exchanger 80 of refrigerator unit 3, via the first connected loop 101, be connected with refrigerant amount adjusting tank 100 in the present embodiment.This refrigerant amount adjusting tank 100 has the volume of regulation, on these case 100 tops, is connected with the first connected loop 101.Be provided with the electric expansion valve 102 of conduct the first switching mechanism with throttling function in this first connected loop 101.It should be noted that, the switching mechanism with throttling function is not limited to this, the mechanism that consists of for example capillary and magnetic valve (open and close valve) for example also can be set in the first connected loop 101 as throttle mechanism.

And, be connected with second connected loop 103 in the middle nip territory that is communicated with these case 100 internal upper parts and refrigerant loop 1 on this refrigerant amount adjusting tank 100.In the present embodiment, the other end of the second connected loop 103 presses suction line 40 to be communicated with as the example in middle nip territory with in the middle of the outlet side of the intercooler 38 of refrigerant loop 1.Be provided with the magnetic valve 104 as the second switching mechanism in this second connected loop 103.

In addition, be connected with the third connecting loop 105 in the middle nip territory that is communicated with this interior bottom of case 100 and refrigerant loop 1 on this refrigerant amount adjusting tank 100.In the present embodiment, third connecting loop 105 and the second connected loop 103 are same, and the other end presses suction line 40 to be communicated with as the example in middle nip territory with in the middle of the outlet side of the intercooler 38 of refrigerant loop 1.Be provided with the magnetic valve 106 as the 3rd switching mechanism in this third connecting loop 105.

Above-mentioned control device C as shown in Figure 2, is connected with outlet side pressure sensor (unit outlet side pressure detection mechanism) 58, extraneous gas temperature sensor 56 at input side.This unit outlet side pressure sensor 56 is positioned at the downstream of refrigerant amount adjusting tank 100, for detection of the pressure of the cold-producing medium towards showcase unit 5A, 5B.Be connected with the fan motor 47M of the air blast 47 of electric expansion valve (the first switching mechanism) 102, magnetic valve (the second switching mechanism) 104, magnetic valve (the 3rd switching mechanism) 106, above-mentioned gas cooler 46 use at the outlet side of above-mentioned control device C.As described later, this control device C carries out the rotating speed control of gas cooler with the fan motor 47M of air blast 47 according to the detected temperatures of extraneous gas temperature sensor 56 and the evaporating temperature of the cold-producing medium in evaporimeter 63A, 63B to details.

(A-1) refrigerant-recovery action

Below, the refrigerant-recovery of refrigerant loop 1 is moved and described.Whether the detected pressures of control device C judging unit outlet side pressure sensor 58 surpasses the recovery threshold value of regulation; whether recovery protection value and above-mentioned gas cooler that whether the detected pressures that perhaps, judges this unit outlet side pressure sensor 58 surpasses the low regulation than above-mentioned recovery threshold value reach maximum with the rotating speed of air blast 47.

In the present embodiment, as an example, in the middle of refrigerant loop 1, press (MP) to take about 8MPa and be appropriate value, therefore this value be set as reclaiming the protection value.Reclaiming Threshold is for example 9MPa higher than this recovery protection value.In addition, as an example, the gas cooler of the present embodiment is made as to 800rpm by the maximum of the rotating speed of air blast 47.In addition, also can be using gas cooler reaches maximum with the rotating speed of air blast 47 after through the stipulated time as condition.

Thus; control device C is in the situation that the detected pressures of unit outlet side pressure sensor 58 is 9MPa over reclaiming threshold value; perhaps; reclaiming below threshold value but surpassing that to reclaim the protection value be 8Mpa in detected pressures; and the above-mentioned gas cooler reaches in the situation of peaked 800rpm with the rotating speed of air blast 47; the gas refrigerant be judged as because of the surplus in refrigerant loop 1 causes this situation of high side pressure abnormal ascending, carries out the refrigerant-recovery action.

In this refrigerant-recovery action, control device C opens electric expansion valve (the first switching mechanism) 102 and magnetic valve (the second switching mechanism) 104 under the state of shut electromagnetic valve (the 3rd switching mechanism) 106.Thus, cooling by gas cooler 46, waste heat recovery heat exchanger 70, Intermediate Heat Exchanger 80 via separator 44 from the high-temperature high-pressure refrigerants of senior side spray outlet 28 ejections of compressor 11,11, via the first connected loop 101 that is provided with the electric expansion valve 102 partially opened, flow in refrigerant amount adjusting tank 100 afterwards.

Now, by opening magnetic valve 104, pressure that can be via the top that is communicated with refrigerant amount adjusting tank 100 and second connected loop 103 in the middle nip territory of refrigerant loop 1, that refrigerant amount adjusting tank 100 is interior discharge outside case.Therefore, even the cold-producing medium in refrigerant loop 1 does not occur in the situation of gas circulation running of liquefaction when externally gas temperature uprises etc., also can reduce the pressure in case 100 and the cold-producing medium that makes to flow in this case liquefies and accumulates in this case 100.That is, by the pressure decreased in refrigerant amount adjusting tank 100, to supercritical pressure, cold-producing medium becomes zone of saturation from gas zones thus, thereby can guarantee liquid level.

Thus, can rapidly and effectively the refrigerant-recovery in refrigerant loop 1 be arrived to refrigerant amount adjusting tank 100.Thereby, can eliminate high-pressure side in refrigerant loop 1 because remaining cold-producing medium becomes the unfavorable condition of abnormal pressure, can prevent the overload running of the compressor 11,11 that causes because of High Abnormal Pressure.

Especially, be communicated with the top of refrigerant amount adjusting tank 100 and the middle nip territory of refrigerant loop 1 via the second connected loop 103, be different from thus the situation with the low-pressure side regional connectivity of refrigerant loop 1, can avoid because of the rise reduction of the cooling effectiveness that causes of low-pressure lateral pressure.

In addition; in the present embodiment; by the detected on high-tension side pressure of unit outlet side pressure sensor 58 in the situation that reclaim below threshold value but surpass the recovery protection value of regulation and be peak to the rotating speed that gas cooler 46 carries out the air blast 47 of air cooling; carry out this refrigerant-recovery action; therefore the operating condition of this air blast 47 can also be considered, thereby the Efficiency Decreasing that state continuance that the high-pressure side because of refrigerant loop 1 uprises extremely causes can be prevented.

(A-2) cold-producing medium keeps action

On the other hand; whether control device C judgement is below 8MPa by the detected on high-tension side pressure of unit outlet side pressure sensor 58 in reclaiming protection value, the present embodiment; in the situation that, lower than reclaiming the protection value, finish refrigerant-recovery and move and shift to the cold-producing medium maintenance and move.At this cold-producing medium, keep in action, control device C maintains the state of shut electromagnetic valve (the 3rd switching mechanism) 106, shut electromagnetic valve (the second switching mechanism) 104, and the aperture of electric expansion valve (the first switching mechanism) 102 is maintained to the aperture in previous refrigerant-recovery action.

It should be noted that, also can make the aperture of above-mentioned electric expansion valve 102 be less than the aperture in the refrigerant-recovery action.Thus, by shut electromagnetic valve 104, can maintain the liquid level in refrigerant amount adjusting tank 100 under the effect of the pressure in the zone, high-pressure side of refrigerant loop 1 via the electric expansion valve 102 of opening.Therefore, the fluid-tight in refrigerant amount adjusting tank 100 can be avoided, security can be guaranteed.Thus, can suitably maintain the circularly cooling dosage in refrigerant loop 1.

In addition, control device C is by making this cold-producing medium keep the aperture of the electric expansion valve 102 in action to be less than the aperture in the refrigerant-recovery action, thereby can effectively eliminate following unfavorable condition: keep in action at cold-producing medium, because the cold-producing medium in refrigerant loop 1 excessively is recovered in refrigerant amount adjusting tank 100, produce the lack of refrigerant in refrigerant loop 1.

(A-3) cold-producing medium is emitted action

And; whether the detected pressures of control device C judging unit outlet side pressure sensor 58 emits threshold value (being the 7MPa left and right in the present embodiment) lower than the regulation lower than above-mentioned recovery protection value (being the 8MPa left and right in this case); whether the detected pressures that perhaps, judges this unit outlet side pressure sensor 58 becomes the following and above-mentioned gas cooler of above-mentioned recovery protection value becomes below the setting of the regulation lower than maximum with the rotating speed of air blast 47.It should be noted that, in the present embodiment, as an example, the setting of this regulation is peaked 3/8 left and right, that is, when peak is 800rpm, the setting of this regulation is the 300rpm left and right.In addition, after also gas cooler can being become below the setting of regulation with the rotating speed of air blast 47 through the stipulated time as condition.

Thus; control device C is in the situation that the detected pressures of unit outlet side pressure sensor 58 is 7MPa lower than emitting threshold value; perhaps; in the situation that detected pressures becomes, to reclaim the protection value be below 8Mpa and the above-mentioned gas cooler becomes below the setting (being 300rpm in this case) of regulation with the rotating speed of air blast 47; be judged as the lack of refrigerant in refrigerant loop 1, carry out cold-producing medium and emit action.

In this cold-producing medium is emitted action, control device C closes electric expansion valve (the first switching mechanism) 102 and magnetic valve (the second switching mechanism) 104, and opens magnetic valve (the 3rd switching mechanism) 106.Thus, accumulate in refrigerant amount adjusting tank 100 the liquid refrigerant magnetic valve 106 that is connected via the bottom with this case 100 third connecting loop 105 of having opened to refrigerant loop 1, emit.Therefore, from by cold-producing medium to sneak under the state of gas refrigerant the situation of emitting to refrigerant loop 1 from the top of refrigerant amount adjusting tank 100 different, can promptly the cold-producing medium in refrigerant amount adjusting tank 100 be emitted to refrigerant loop 1, can make thus refrigerating plant turn round with high efficiency.

(A-4) cold-producing medium keeps action

Afterwards; more than whether control device C judgement is become and reclaimed protection value (being 8MPa in the present embodiment) by the detected on high-tension side pressure of unit outlet side pressure sensor 58, in the situation that surpass, reclaim the protection value and finish cold-producing medium and emit action and shift to as mentioned above cold-producing medium and keep action.Afterwards; high side pressure according to refrigerant loop 1; repeatedly carrying out this refrigerant-recovery action-cold-producing medium keeps action-cold-producing medium to emit action-cold-producing medium maintenance action; can control refrigerant-recovery, emit according to high side pressure thus, can carry out reliably high voltage protective and prevent the overload running.Thus, the refrigerating capacity of refrigerating plant can be guaranteed, suitableization of COP can be realized.

Especially in the present embodiment, not only can consider high side pressure, can also consider to gas cooler 46 carry out air cooling air blast 47 rotating speed and control refrigerant-recovery, emit action, thereby can prevent the Efficiency Decreasing that state continuance that the high-pressure side because of refrigerant loop 1 uprises extremely causes.

In addition, in the present embodiment, the second connected loop 103 and third connecting loop 105 all are communicated with the outlet side of the intercooler 38 of refrigerant loop 1.Thus, can prevent the pressure loss of intercooler 38, thereby cold-producing medium 1 successfully can be emitted from refrigerant amount adjusting tank 100 to refrigerant loop.

In addition, in the situation that the running of compressor 11,11 stops, control device C carries out cold-producing medium and emits action.Thus, this unfavorable condition of lack of refrigerant in the time of can eliminating compressor 11,11 starting in refrigerant loop 1, can realize suitable high side pressure according to the on high-tension side pressure of the compressor 11 based on running.

In addition, in this case, compressor 11 (compressing mechanism) has adopted the two-stage compression formula rotary compressor of pack in closed container 12 first, second compressing member 18,20 and electric element 14, but in addition, also can adopt the form that can from middle splenium, cold-producing medium be taken out, import by two single-stage rotary compressors or other forms of compressor.

(B) separating cycle

Next, the separating cycle of the refrigerating plant R in the present embodiment described.In refrigerating plant R in the present embodiment, by the second rotary compression element (senior side) 20, separator 44, gas cooler 46, current divider 82, auxiliary throttle mechanism (auxiliary expansion valve) 83, Intermediate Heat Exchanger 80, main throttle mechanism (main expansion valve) 62A, 62B, evaporimeter 63A, the 63B of the first rotary compression element (rudimentary side) 18 of each compressor 11,11, intercooler 38, the device of the interflow as converging device 81 that makes the mobile interflow of two kinds of fluids, each compressor 11,11, form kind of refrigeration cycle.

Current divider 82 is by from gas cooler 46, cold-producing medium out is divided into the mobile part flow arrangement of two.That is, the current divider 82 of the present embodiment will be from gas cooler 46 cold-producing medium out be divided into the first cold-producing medium stream and second refrigerant flows, make the first cold-producing medium stream flow to subsidiary loop, make second refrigerant stream flow to major loop.

In Fig. 1, major loop is the refrigerant loop of the ring-type that consists of the first rotary compression element 18, intercooler 38, interflow device 81, the second rotary compression element 20, gas cooler 46, current divider 82, the second stream 80B of Intermediate Heat Exchanger 80, main throttle mechanism 62A, 62B, evaporimeter 63A, 63A, and subsidiary loop means from current divider 82 successively through the first stream 80A of auxiliary diversion mechanism 83, Intermediate Heat Exchanger 80 to the loop of collaborating device 81.

Auxiliary throttle mechanism 83 is mechanisms that the first cold-producing medium stream to being flowed in subsidiary loop by above-mentioned current divider 82 shuntings is reduced pressure.Intermediate Heat Exchanger 80 is the heat exchangers that carry out the first cold-producing medium stream in the auxiliary post-decompression subsidiary loop of throttle mechanism 83 and the heat exchange of second refrigerant stream by after current divider 82 shuntings.In this Intermediate Heat Exchanger 80, the first stream 80A that the second stream 80B that second refrigerant stream is flowed and above-mentioned the first cold-producing medium stream are flowed is can carry out the setting that concerns of heat exchange, owing to passing through the second stream 80B of this Intermediate Heat Exchanger 80, thereby the first cold-producing medium stream that second refrigerant stream can be flowed in the first stream 80A is cooling, therefore can reduce the specific enthalpy of evaporimeter 63A, 63B.

Above-mentioned control device C as shown in Figure 2, is connected with ejection temperature sensor (ejection temperature testing organization) 50, unit outlet side pressure sensor (unit outlet side pressure detection mechanism) 58, middle pressure pressure sensor (middle pressure pressure testing agency) 49, low-pressure sensor (suction pressure testing agency) 32, gas cooler exit temperature sensor (gas cooler exit temperature testing agency) 52, unit outlet temperature sensor (unit outlet temperature testing agency) 54, unit inlet temperature sensor (inlet temperature testing agency) 34 at input side.

Ejection temperature sensor 50 is arranged at the senior side spray outlet 28 of compressor 11,11, for detection of the ejection temperature of the cold-producing medium from the second rotary compression element 20 ejections.Unit outlet side pressure sensor 58 is positioned at the downstream of refrigerant amount adjusting tank 100, for detection of the pressure of the cold-producing medium towards showcase unit 5A, 5B.Low-pressure sensor 32 is positioned at the low-pressure side of refrigerant loop 1, be positioned in the present embodiment the downstream of each evaporimeter 63A, 63B, and be located at the refrigerant piping 9 be connected with the rudimentary side draught entrance 22,22 of compressor 11,11, for detection of the suction pressure of the cold-producing medium towards this cold-producing medium ingress pipe 30.Middle pressure pressure sensor 49 is positioned at the middle nip territory of refrigerant loop 1, is positioned in the present embodiment the subsidiary loop of separating cycle, detects the pressure of the first cold-producing medium stream after the first stream 80A of Intermediate Heat Exchanger 80.

Gas cooler exit temperature sensor 52 is located at the outlet side of gas cooler 46, for detection of the temperature (GCT) from this gas cooler 46 cold-producing medium out.Unit outlet temperature sensor 54 is located at the outlet side of the Intermediate Heat Exchanger 80 be connected with refrigerant piping 7, for detection of unit outlet temperature (LT).Unit inlet temperature sensor 34 is located at the refrigerant piping 9 be connected with the rudimentary side draught entrance 22 of compressor 11, for detection of the inlet temperature of the cold-producing medium towards this cold-producing medium ingress pipe 30.And, be connected with the auxiliary throttle mechanism 83 that forms this separating cycle at outlet side.Be somebody's turn to do the aperture of auxiliary throttle mechanism 83 by Step-motor Control.

Below, the aperture of auxiliary throttle mechanism 83 is controlled and described in detail.Auxiliary throttle mechanism 83 is set to the initial valve aperture of regulation the zero hour in the running of compressor 11.Afterwards, determine the operational ton of the valve opening increase that makes auxiliary throttle mechanism 83 according to the first following controlled quentity controlled variable, the second controlled quentity controlled variable, the 3rd controlled quentity controlled variable.

(B-1) valve opening of auxiliary throttle mechanism increases control

The first controlled quentity controlled variable (DTcont) obtains according to the ejection refrigerant temperature DT of compressor 11.Whether control device C judges by the detected temperature DT of above-mentioned ejection temperature sensor 50 higher than setting DT0, in the situation that this ejection refrigerant temperature DT sets the controlled quentity controlled variable of the directive effect increased towards the aperture that makes auxiliary throttle mechanism 83 for higher than setting DT0.This setting DT0 is set as the temperature (as an example be+95 ℃) slightly lower than the critical temperature of the suitable running that can realize compressor 11 (as an example, being+100 ℃), in the situation that temperature has risen, by increasing the aperture of auxiliary throttle mechanism 83, thereby the temperature that suppresses this compressor 11 rises, and is controlled so that compressor 11 does not reach critical temperature.

The second controlled quentity controlled variable (MPcont) is the mobile refrigerant amount of subsidiary loop for being adjusted at separating cycle and realize the controlled quentity controlled variable of suitableization of intermediate pressure (MP).In the present embodiment, judgement by the pressure MP in the middle nip territory of the detected refrigerant loop 1 of middle pressure pressure sensor 49 whether higher than suitable intermediate pressure value, in the situation that the pressure MP in this middle nip territory is lower than suitable intermediate pressure value, the directive effect increased towards the aperture that makes auxiliary throttle mechanism 83, wherein, described suitable intermediate pressure value is calculated (obtaining) according to the high side pressure HP by unit outlet side pressure sensor 58 detected refrigerant loops 1 with by the low-pressure lateral pressure LP of the detected refrigerant loop 1 of low-pressure sensor 32.

It should be noted that, suitably intermediate pressure value also can be calculated by the geometrical mean of detected high side pressure HP and low-pressure lateral pressure LP, in addition, can also obtain suitable intermediate pressure value by high side pressure HP and low-pressure lateral pressure LP experimentally in advance, according to the tables of data of constructing thus, determine suitable intermediate pressure value.

In addition, in the present embodiment, the suitable intermediate pressure value of relatively being obtained by high side pressure HP, low-pressure lateral pressure LP and the pressure MP in middle nip territory, thereby determine the second controlled quentity controlled variable (MPcont), but be not limited thereto, for example, can be in the following way.; obtain overcompression decision content MPO according to the pressure MP in the middle nip territory by the detected refrigerant loop 1 of middle pressure pressure sensor 49 with by the low-pressure lateral pressure LP of the detected refrigerant loop 1 of low-pressure lateral pressure sensor 32; judge that whether this overcompression decision content MPO is lower than the high side pressure HP by unit outlet side pressure sensor 58 detected refrigerant loops 1; in the situation that overcompression decision content MPO is lower than high side pressure HP, towards the directive effect of the aperture increase that makes auxiliary throttle mechanism 83.Control by the aperture that makes this second controlled quentity controlled variable be reflected to auxiliary throttle mechanism 83, can suitably keep thus the pressure MP in high side pressure HP, middle nip territory, the pressure differential of low-pressure lateral pressure LP, can realize the stabilisation of the running of kind of refrigeration cycle.

The 3rd controlled quentity controlled variable (SPcont) is the controlled quentity controlled variable from suitableization of the second stream refrigerator temperature LT out of middle heat exchanger 80 for realization.In the present embodiment, control device C judgement is by the temperature GCT of the detected cold-producing medium after gas cooler 46 of gas cooler exit temperature sensor 52 and whether be less than setting SP by detected poor (GCT-LT) that passes through the temperature LT of Intermediate Heat Exchanger second refrigerant stream after 80s of unit outlet temperature sensor 54, in the situation that little and setting SP, the mode effect increased towards the aperture that makes auxiliary throttle mechanism 83.

Here, setting SP is set as in following two kinds of situations different, these two kinds of situations situation in zone of saturation that is high side pressure HP at the situation of the supercritical range of this cold-producing medium and high side pressure HP.In the present embodiment, according to by the detected extraneous gas temperature of extraneous gas temperature sensor 56, judging that high side pressure HP is at supercritical range or in zone of saturation, in the situation that this extraneous gas temperature is high, for example, more than+31 ℃, judgement is at supercritical range, in the situation that externally gas temperature is low, for example be less than+31 ℃, judgement is in zone of saturation.And, in the situation that be judged as at supercritical range, by setting SP, set highly, in the situation that be judged as in zone of saturation, by setting SP, set lowly.In the present embodiment, during for supercritical range, setting SP is set as 35 ℃, and during for zone of saturation, setting SP is set as 20 ℃.

Control device C adds up to three controlled quentity controlled variables that as above obtain, add up to the first controlled quentity controlled variable (DTcont), the second controlled quentity controlled variable (MPcont) and the 3rd controlled quentity controlled variable (SPcont), thereby determine the operational ton of the valve opening of auxiliary throttle mechanism 83, based on this, increase valve opening.

(B-2) valve opening of auxiliary throttle mechanism is dwindled control

In addition, control device C is according to the temperature LT of the second refrigerant after 80s through Intermediate Heat Exchanger stream or poor by the temperature GCT of the ejection refrigerant temperature DT of compressor 11 ejections and cold-producing medium after gas cooler 46, determines the operational ton that the valve opening that makes auxiliary throttle mechanism 83 is dwindled.

That is whether the temperature LT that, control device C judgement is flowed by the detected second refrigerant after 80s through Intermediate Heat Exchanger of unit outlet temperature sensor 54 is lower than setting.In the present embodiment, as an example, this setting is set as 0 ℃.Thus, in the situation that the unit outlet temperature is below 0 ℃, the direction operation dwindled towards the aperture that makes throttling auxiliary body 83, can eliminate the second refrigerant stream that is cooled at Intermediate Heat Exchanger 80 by supercooled unfavorable condition.

In addition, control device C judgement by poor (DT-GCT) of the detected temperature DT of ejection temperature sensor 50 and temperature GCT by the detected cold-producing medium after gas cooler 46 of gas cooler exit temperature sensor 52 whether lower than setting TDT, in the situation that low, the directive effect of dwindling towards the aperture that makes auxiliary throttle mechanism 83.

Here, setting TDT is set as in following two kinds of situations different, that is, and and these two kinds of situations situation in zone of saturation that is high side pressure HP at the situation of the supercritical range of this cold-producing medium and high side pressure HP.In the present embodiment, same with the situation of obtaining above-mentioned the 3rd controlled quentity controlled variable, judge that according to the extraneous gas temperature high side pressure HP is at supercritical range or in zone of saturation.And, in the situation that be judged as at supercritical range, by setting TDT, set lowly, in the situation that be judged as in zone of saturation, by setting TDT, set highly.In the present embodiment, when supercritical range, setting TDT is set as 10 ℃, is set as 35 ℃ when zone of saturation.

The temperature LT that control device C flows at the second refrigerant after 80s through Intermediate Heat Exchanger is in the situation that below setting (0 ℃), perhaps in the situation that from the difference of the ejection refrigerant temperature DT of compressor 11 ejection and the temperature GCT of cold-producing medium after gas cooler 46 lower than setting TDT, determine the operational ton of the valve opening of auxiliary throttle mechanism 38, dwindle thus valve opening, and do not carry out above-mentioned valve opening, do not increase control.

In the refrigerating plant R of the present embodiment that possesses separating cycle as described above, can be by the cold-producing medium shunting after gas cooler 46 heat radiations, and carry out cooling second refrigerant stream by the first cold-producing medium stream by after auxiliary throttle mechanism 83 puffings, thereby the specific enthalpy that can dwindle each evaporimeter 63A, 63B entrance.Thus, can increase refrigeration, compare with existing apparatus, can effectively improve performance.In addition, because the first cold-producing medium stream after shunting returns to the second rotary compression element 20 (middle splenium) from the senior side draught entrance 26 of compressor 11, therefore suck the amount minimizing of the second refrigerant stream the first rotary compression element 18 (low voltage section) from the rudimentary side draught entrance 22 of compressor 11, reduce for the compression work amount that is compressed to middle the first rotary compression element 18 (rudimentary section) of pressing from low pressure.Consequently, the compression power of compressor 11 reduces and the coefficient of refrigerating performance raising.

Here, the effect of above-mentioned so-called separating cycle depends on the amount that the first cold-producing medium flows and second refrigerant flows flowed in Intermediate Heat Exchanger 80.That is, if the amount of the first cold-producing medium stream is too much, the quantity not sufficient that in evaporimeter 63A, 63B, the second refrigerant of final evaporation flows, hence one can see that, on the contrary if the amount of the first cold-producing medium stream is very few, the effect of separating cycle weakens.On the other hand, the intermediate pressure that the pressure flowed by post-decompression the first cold-producing medium of auxiliary throttle mechanism 83 is refrigerant loop 1, the amount of controlling the first cold-producing medium stream is to control this intermediate pressure.

Here, in the present embodiment, calculate the first controlled quentity controlled variable, the second controlled quentity controlled variable, the 3rd controlled quentity controlled variable, add up to the above-mentioned first to the 3rd controlled quentity controlled variable, determine thus the operational ton of the valve opening increase that makes auxiliary throttle mechanism 83, wherein, as mentioned above, described the first controlled quentity controlled variable is in the situation that the controlled quentity controlled variable of the directive effect that the temperature DT of the ejection cold-producing medium sprayed from compressor 11 (ejection temperature sensor 50) increases towards the aperture that makes auxiliary throttle mechanism 83 higher than setting DT0, described the second controlled quentity controlled variable is in the situation that the controlled quentity controlled variable of the directive effect that the suitable intermediate pressure value that the pressure MP in the middle nip territory of refrigerant loop 1 obtains lower than the high side pressure HP by refrigerant loop 1 and low-pressure lateral pressure LP increases towards the aperture that makes auxiliary throttle mechanism 83, described the 3rd controlled quentity controlled variable is in the situation that the temperature LT that the temperature GCT of the cold-producing medium after gas cooler 46 and process Intermediate Heat Exchanger second refrigerant after 80s flows poor (GCT-LT) is less than the controlled quentity controlled variable of setting SP towards the directive effect of the aperture increase that makes auxiliary throttle mechanism 83.In addition, in the situation that temperature LT is lower than setting, or in the situation that temperature DT-GCT, lower than setting TDT, determines operational ton on the direction of the valve opening of dwindling auxiliary throttle mechanism 83.

Thus, the temperature DT that can will spray cold-producing medium by the first controlled quentity controlled variable remains on below setting DT0, can the intermediate pressure MP of refrigerant loop 1 suitably be changed by the second controlled quentity controlled variable, can suitably keep thus the pressure differential of low-pressure lateral pressure LP, intermediate pressure MP, high side pressure HP.In addition, can reduce the temperature LT of the second refrigerant stream after 80s through Intermediate Heat Exchanger by the 3rd controlled quentity controlled variable, keep refrigeration.In sum, generally speaking can realize high efficiency and the stabilisation of refrigerating plant.

In addition, control device C in the situation that high side pressure HP in supercritical range, improve setting SP and reduce setting TDT, and in the situation that high side pressure HP is in zone of saturation, reduce setting SP and improve setting TDT, can be distinguished into thus setting SP that the situation of high side pressure HP in supercritical range and the situation in zone of saturation change the 3rd controlled quentity controlled variable and the first controlled quentity controlled variable and TDT and controlled.

Thus, even in the situation that high side pressure HP can guarantee the degree of superheat of Intermediate Heat Exchanger 80 reliably in zone of saturation, can avoid producing back this unfavorable condition of liquid in compressor 11.In addition, in the situation that high side pressure HP, in supercritical range, owing to can not producing such liquid that returns, therefore can be made the setting of efficiency comes first.

It should be noted that, following mode also can suitably be changed with the above-mentioned intermediate pressure MP of refrigerant loop that similarly makes, thereby can suitably keep low-pressure lateral pressure LP, intermediate pressure MP, the pressure differential of high side pressure HP, described mode refers to: the second controlled quentity controlled variable that makes above-described embodiment in the situation that by the pressure MP in the middle nip territory of refrigerant loop 1 and overcompression decision content MPO that low-pressure lateral pressure LP obtains lower than the high side pressure HP of refrigerant loop the second controlled quentity controlled variable towards the directive effect that increases the aperture of assisting throttle mechanism, add up to the first to the 3rd controlled quentity controlled variable, determine thus the operational ton of the valve opening of auxiliary throttle mechanism.

In addition, from the Intermediate Heat Exchanger 80 of this embodiment, the interflow device 81 of the first cold-producing medium stream out outlet side by being located at intercooler 38 can return to the outlet side of this intercooler 38, prevent the pressure loss in intercooler 38, thus can be successfully by from middle heat exchanger 80 cold-producing medium stream out press the side interflow in the middle of refrigerant loop 1.

(C) waste heat recovery heat exchanger

Next, the waste heat recovery heat exchanger 70 refrigerating plant R of the present embodiment adopted describes.The waste heat recovery heat exchanger 70 of the present embodiment is the heat exchanger carried out through gas cooler 46 heat exchange of the carbon dioxide coolant (Waste Heat Recovery medium) of the heat pump unit of not shown hot-water supply by the second refrigerant stream after current divider 82 shuntings and formation.The hot-water supply of the present embodiment consists of heat pump unit, and described heat pump unit possesses: by refrigerant piping, not shown coolant compressor, water heat exchanger, decompressor, evaporimeter are connected into to the refrigerant loop that tubulose forms; Make its water loop of returning to the thermal storage water tank after water in the thermal storage water tank is heated by water heat exchanger, the evaporimeter of this heat pump unit consists of the Waste Heat Recovery medium stream 70B of above-mentioned waste heat recovery heat exchanger 70.Thus, as mentioned above, in this waste heat recovery heat exchanger 70, the refrigerant flow path 70A that second refrigerant stream in separating cycle is mobile and Waste Heat Recovery medium stream 70B are can carry out the setting that concerns of heat exchange, the cold-producing medium of utilization mobile heat pump unit in the Waste Heat Recovery medium stream 70B of this waste heat recovery heat exchanger 70 passes through, and at the second refrigerant stream after gas cooler 46 in refrigerant flow path 70A, is cooled thus.

Here, in the present embodiment, the second refrigerant stream flowed in the refrigerant flow path 70A of waste heat recovery heat exchanger 70 from gas cooler 46 out enters the Intermediate Heat Exchanger 80 that forms above-mentioned separating cycle.Thus, the impact of extraneous gas temperature is little, can effectively be recovered in the used heat of cold-producing medium mobile in refrigerant flow path 70A and be used in the heating of cold-producing medium mobile in forming the Waste Heat Recovery medium stream 70B of hot-water supply by waste heat recovery heat exchanger 70, effectively generating hot water.

In addition, because the second refrigerant be configured to from gas cooler 46 out enters Intermediate Heat Exchanger 80 flows structure mobile in waste heat recovery heat exchanger 70, therefore in the situation that the utilization of hot water generation side (hot-water supply side) is many, can reduce the refrigerant temperature of the second refrigerant stream that flows to Intermediate Heat Exchanger 80, therefore can reduce the refrigerant amount of the first cold-producing medium stream that flows to Intermediate Heat Exchanger 80.Thus, can increase mobile refrigerant amount in second refrigerant stream, can increase the evaporation capacity of the cold-producing medium in evaporimeter 63A, 63B, thereby improve the effect of kind of refrigeration cycle.

Especially in the situation that used as in this embodiment carbon dioxide as cold-producing medium, refrigerating capacity can be effectively improved, the raising of performance can be realized.

In addition, in the refrigerating plant R of the present embodiment, the gas cooler bypass circulation 71 of walking around gas cooler 46 also can be set.In this case, be provided with magnetic valve 72 in gas cooler bypass circulation 71, this magnetic valve (valve gear) 72 is controlled and is opened and closed by control device C as above.

Thus, use amount in hot-water supply is many, can't make in the situation that in the Waste Heat Recovery medium stream 70B (evaporimeter) of heat pump unit mobile cold-producing medium fully evaporate, control device C can open magnetic valve 72, the part of the high temperature refrigerant that flows into to gas cooler 46 is flowed into to gas cooler bypass circulation 71, and make high temperature refrigerant directly by the refrigerant flow path 70A of waste heat recovery heat exchanger 70.Thus, can effectively utilize used heat and carry out the temperature-compensating of hot-water supply side.

(D) control of air blast for gas cooler

Next, the control of gas cooler 46 being carried out to the gas cooler use air blast 47 of air cooling as above is described.The control device C of the present embodiment as shown in Figure 2, is connected with high-pressure sensor (high-pressure testing agency) 48,48, low-pressure sensor 32, extraneous gas temperature sensor 56 at input side.Here, because the evaporating temperature TE in the detected pressure of low-pressure sensor 32 and evaporimeter 63A, 63B has certain relation, so control device C is according to obtained the evaporating temperature TE of cold-producing medium in evaporimeter 63A, 63B by the detected conversion pressure of this low-pressure sensor 32.In addition, the outlet side at control device C is connected with the air blast 47 for gas cooler that gas cooler 46 is carried out to air cooling.

Control device C controls the rotating speed of gas cooler with air blast 47, so that become desired value (the target high pressure: THP) of regulation by the detected high side pressure HP of high-pressure sensor 48.Here, the evaporating temperature TE of target high pressure THP cold-producing medium in extraneous gas temperature T A and evaporimeter 63A, 63B determines.

In the high-pressure side of refrigerant loop 1 becomes the refrigerating plant R more than supercritical pressure as in this embodiment, externally gas temperature TA in the situation that a certain temperature, for example, below+30 ℃, carry out saturated circulation, in the situation that, higher than+30 ℃, carry out gas circulation.Therefore while carrying out gas circulation, cold-producing medium does not liquefy, and the refrigerant amount in the refrigerant loop 1 thus the time is determined temperature and pressure uniquely.Therefore, according to the difference of extraneous gas temperature T A, target high pressure THP difference.

In the present embodiment, as an example, in the situation that by the detected extraneous gas temperature T of extraneous gas temperature sensor 56 A for example, below lower limit temperature (0 ℃), target high pressure THP the regulation lower limit THPL fix.In addition, externally gas temperature TA in the situation that, higher than more than the set point of temperature (ceiling temperature) of 30 ℃, target high pressure THP fixes at set upper limit value THPH.And externally gas temperature TA, higher than in lower limit temperature and the situation lower than ceiling temperature, solves target high pressure THP as described below.

Extraneous gas temperature T A is more lower than for example+30 ℃ of the fiducial temperatures of stipulating, get over towards this desired value of orientation determination THP of the desired value THP that reduces high side pressure, extraneous gas temperature T A more, higher than the fiducial temperature of regulation, gets over towards this desired value of the orientation determination THP that improves desired value THP.In addition, as mentioned above, in evaporimeter 63A, 63B that according to this low-pressure sensor 32, detected conversion pressure is obtained, the evaporating temperature TE of cold-producing medium is more higher than the fiducial temperature of stipulating, get over towards this desired value of orientation determination THP of the desired value THP that improves high side pressure, evaporating temperature TE more, lower than the fiducial temperature of regulation, gets over towards this desired value of the orientation determination THP that reduces desired value THP.Fig. 3 means the figure by the trend of extraneous gas temperature T A and the definite target high pressure THP of evaporating temperature TE.

It should be noted that, in the present embodiment, control device C is used calculating formula to calculate target high pressure THP by extraneous gas temperature T A and evaporating temperature TE, but is not limited to this, also can obtain target high pressure THP according to the tables of data obtained by extraneous gas temperature T A and evaporating temperature TE in advance.

And control device C basis is by the deviation e of high-pressure sensor (high-pressure testing agency) 48 detected high side pressure HP, target high pressure THP, above-mentioned HP and THP, the P (ratio based on this deviation e.With being in proportion of deviation e, dwindle the control of the direction of this deviation e), D (differential.Dwindle the control of direction of the variation of deviation e), carry out proportional integral and calculate, determine the gas cooler of deriving as the operational ton rotating speed with air blast 47.For this rotating speed, THP is higher for the target high pressure, and the rotating speed of air blast 47 is higher, and THP is lower for the target high pressure, and the rotating speed of air blast 47 is lower.

Thus, control device C controls the rotating speed of gas cooler with air blast 47 according to evaporating temperature (detected low pressure converts and obtains according to the low-pressure sensor 32) TE of cold-producing medium in extraneous gas temperature T A and evaporimeter, thus, become in the refrigerating plant R of supercritical pressure in high-pressure side, also can control gas cooler and form suitable high-pressure with the rotating speed of air blast 47.Thus, can reduce the noise that gas cooler produces with the running of air blast 47, and realize high efficiency running simultaneously.

In the present embodiment, control device C determines the desired value THP of the high side pressure of refrigerant loop 1 according to extraneous gas temperature T A and evaporating temperature TE, and control gas cooler with air blast 47 so that high side pressure becomes desired value THP, can consider thus to be varied to according to extraneous gas temperature T A the state of the cold-producing medium of saturated circulation and gas circulation, and realize preferred high side pressure according to evaporating temperature TE, can realize high efficiency running thus, wherein, the mode of desired value THP of high side pressure of determining refrigerant loop 1 is as described below: for example extraneous gas temperature T A is lower, more reduce desired value THP, evaporating temperature TE is higher, more on the direction that improves desired value THP, determine this desired value THP.So, the present invention is effective especially in having used the supercritical refrigerant loop (supercritical refrigeration cycle) of carbon dioxide as cold-producing medium.

(E) separator

On the other hand, be provided with separator 44 in the high pressure ejection pipe arrangement 42 of the senior side spray outlet 28 of connection compressor 11 as above and gas cooler 46.This separator 44 is for separating with cold-producing medium and catch from the contained oil of ejection cold-producing medium of the high pressure of compressor 11 ejection, at this separator 44, is connected with the oil return circuit 73 that the oil that makes to capture returns to compressor 11.Be provided with the oil cooler 74 of the cooling oil captured in this oil return circuit 73, downstream at this oil cooler 74, oil return circuit 73 is branched off into two systems, via filter 75 and flow rate regulating valve (motor-driven valve) 76, with the closed container 12 of compressor 11, is connected respectively.As mentioned above, in the middle of being retained as in the closed container 12 due to compressor 11, press, turn back in this closed container 12 under the effect of the pressure reduction of the middle pressure in the high pressure of the oil therefore captured oil eliminator 44 in and closed container 12.In addition, the closed container 12 at compressor 11 is provided with the oil surface sensor 77 for detection of the pasta that is kept at the oil in this closed container 12.

In addition, be provided with the oil bypass loop 78 that makes oil cooler 74 bypass at this oil return circuit 73, be provided with magnetic valve (valve gear) 79 in this oil bypass loop 78.This magnetic valve 79 is controlled and is opened and closed by control device C as above.In addition, as mentioned above, this oil cooler 74 is arranged in identical wind path 45 with above-mentioned gas cooler 46, by gas cooler, with air blast 47, carries out air cooling.

According to above structure, whether the control device C judgement detected temperature of extraneous gas temperature sensor 56 in being located at wind path 45 is below the oily low temperature (setting) of regulation, in the situation that surpass oily low temperature, the magnetic valve 79 of closing oil bypass loop 78.

Thus, from the senior side spray of each compressor 11,11, export the downstream interflow of the high-temperature high-pressure refrigerant of 28 ejections at the second rotary compression element 20,20, be pulled to refrigerator unit 3,3 via separator 44, gas cooler 46 etc.Flow into contained oil in the high-temperature high-pressure refrigerant in separator 44 separates with cold-producing medium and is captured in separator 44.And, due to the closed container 12 of compressor 11, press in the middle of being retained as, return to compressor 11 via oil return circuit 28 under the effect of the pressure reduction of the middle pressure in the high pressure of the oil therefore captured oil eliminator 44 in and closed container 12.

Flow into oil in oil return circuit 28 in gas cooler 46, being provided in the oil cooler 74 of same wind path 45 by the running of air blast 47 by air cooling.After this oil cooler 74, be separated to two systems and return to compressor 11 through filter 75, flow rate regulating valve 76.Thus, the oil that becomes high temperature together with high temperature refrigerant is cooling and return to compressor 11 by oil cooler 74, and the temperature that therefore can suppress compressor 11 rises.

On the other hand, by the detected temperature of extraneous gas temperature sensor 56 in the situation that the regulation oily lower limit temperature (setting) below, control device C opens the magnetic valve 79 in oil bypass loop 78.Thus, return to compressor 11,11 without oil cooler 74 via the oil bypass loop 78 of oil return circuit 28 with the oil after cold-producing medium separates in separator 44.In addition, in the situation that reached the oily ceiling temperature that exceeds set point of temperature than oily lower limit temperature, control device C shut electromagnetic valve 79 by the detected temperature of extraneous gas temperature sensor 56.

Thus, cause that oil temperature also reduces while causing oil viscosity to rise this situation, can make the oil in separator 44 return to compressor 11 without oil cooler 74 via oil bypass loop 78 by opening magnetic valve 79 reducing because of the extraneous gas temperature.Thus, can make oil successfully return to compressor 11.

Especially in the present embodiment, due to oil cooler 74 and gas cooler 46 are arranged in same wind path 45, and independently carry out the control of air blast 47 with the temperature of oil cooler 74 as described above, thereby easily dissolve in oil because the running of air blast 47 causes the excessive temperature (more than necessity) of oil cooler 74 to reduce cold-producing medium, but, by utilizing control device C to open the magnetic valve 79 in oil bypass loop 78, can make the oil in separator 44 successfully return to compressor 11 without oil cooler 74 via oil bypass loop 78.Therefore, especially in the situation that can't adjust the air cooling amount, can simplify and control and obtain effect.

In addition, control device C is externally in the situation of oily lower limit temperature (setting) of gas temperature lower than regulation, utilize magnetic valve 79 to open the stream in oil bypass loop 78, the situation that prevents thus cold-producing medium from dissolving in oil and cause oil viscosity to rise, thus can make reliably the oil in separator 44 return to compressor 11 via the oil bypass loop 78 that oil cooler 74 is roundabout.

In addition, in the present embodiment, carry out the open and close controlling of magnetic valve 79 according to the detected temperature of extraneous gas temperature sensor 56 in being located at wind path 45, but be not limited to this, the mechanism of the temperature that detects separator 44 for example also can be set, in the situation that by the detected temperature of this temperature testing organization lower than setting, utilize magnetic valve 79 to open the stream in oil bypass loop 78.In this case, also can prevent reliably that cold-producing medium from dissolving in oil and the situation that causes oil viscosity to rise, thereby can make reliably the oil in separator 44 return to compressor 11 via the oil bypass loop 78 that oil cooler 74 is roundabout.

In addition, in the situation that used as in this embodiment carbon dioxide as cold-producing medium, by being controlled as described above, can make oil successfully return to compressor 11, and effectively improve refrigerating capacity, can realize the raising of performance.

(F) startability of compressor improves (bypass circulation)

Next, the startability improvement of compressor 11 is controlled and described.As shown in Figure 2, be provided with the bypass circulation 84 of the low-pressure side of the middle nip territory of refrigerant loop 1 of outlet side of intercooler 38 of connection refrigerating plant R as described above and refrigerant loop 1, wherein, in the present embodiment, the middle nip territory of the refrigerant loop 1 of the outlet side of intercooler 38 refers to above-mentioned second or the third connecting loop 104,105 be connected with the outlet side of this intercooler 38, and the low-pressure side of refrigerant loop 1 refers to the refrigerant outlet side of evaporimeter 63A, 63B.Be provided with magnetic valve (valve gear) 85 in this bypass circulation 84.And as shown in Figure 2, control device C connects compressor 11,11 and magnetic valve 85.Control device C can detect the operating frequency of (obtaining) compressor 11.

According to above structure, the startability of compressor 11 is improved to control action and describe.As mentioned above, under the state of compressor 11 running, in the middle of being boosted to by this first rotary compression element 18, the refrigerant gas of low pressure that is drawn into the low voltage section of the first rotary compression element 18 by rudimentary side draught entrance 22 presses and to the interior ejection of closed container 12.The refrigerant gas of pressing in the middle of in closed container 12 exports 24 to 36 ejections of centre pressure ejection pipe arrangement from the rudimentary side spray of compressor 11, via the middle pressure suction line 40 that connects intercooler 38, is inhaled into senior side draught entrance 26.From by the first rotary compression element 18 ejection and the zone be inhaled into the second rotary compression element 20 via senior side draught entrance 26 till be set to the middle nip territory.

Being drawn into compression that the refrigerant gas of middle pressure of the middle splenium of the second rotary compression element 20 carried out the second level by this second rotary compression element 20 by senior side draught entrance 26 becomes the refrigerant gas of HTHP, and the zone be ejected to high pressure ejection pipe arrangement 42 by senior side spray outlet 28 till main throttle mechanism 62A, the 62B of separator 44, gas cooler 46, waste heat recovery heat exchanger 70, Intermediate Heat Exchanger 80, refrigerant piping 7, showcase unit 5A, 5B is high-pressure side.

And, by main throttle mechanism 62A, 62B puffing, the zone till from evaporimeter 63A, the 63B in their downstreams to the rudimentary side draught entrance 22 be communicated with the first rotary compression element 18 is as the low-pressure side of refrigerant loop 1.

After the running of above-mentioned compressor 11 stops again during starting compressor 11, before from compressor 11 startings to the operating frequency that rises to regulation during, control device C opens magnetic valve 85 and opens the stream of bypass circulation 84.The operating frequency of this regulation refers to that compressor 11 can be had the operating frequency of the torque control of actual effect, as an example, is made as 35Hz in the present embodiment.

Thus, at compressor 11, from halted state, start and rise to before the operating frequency of this regulation during, by opening magnetic valve 85, utilize the first rotary compression element 18 to press in the middle of boosting to, the low-pressure side zone to refrigerant loop 1 flows into via bypass circulation 84 to press the cold-producing mediums in 36 ejections of ejection pipe arrangement the middle nip territory after intercooler 38 to centre from rudimentary side spray outlet 24.Thus, the middle nip territory of refrigerant loop 1 and the pressure in low-pressure side zone are all pressed.

Thus, although compressor 11 from start and rise to the operating frequency of regulation before start-up period can't guarantee the torque of regulation, but by being formed all, middle nip territory and low-pressure side zone pressing during this period, even under the situation easily uprised because of the high and middle pressure-volume of extraneous gas temperature, the unfavorable condition of the nearly high pressure of crimping in the middle of also can eliminating.

Therefore, during the torque deficiency produced at the start-up period of compressor 11, can avoid in advance approaching with the pressure of high-pressure area the poor starting caused because of the pressure in middle nip territory, can realize stablizing and high efficiency running.In addition, control device C is after the operating frequency of detected compressor 11 rises to the operating frequency of regulation, and the stream of shut electromagnetic valve 85 inaccessible bypass circulation 84, carry out common kind of refrigeration cycle as above thus.

(G) startability of compressor improves (check-valves)

High pressure ejection pipe arrangement 42 at each compressor 11 of the present embodiment is provided with cold-producing medium adjuster 91.Here, with reference to the local vertical profile side view of the cold-producing medium adjuster 91 of Fig. 4 and the broken section top view of Fig. 5, cold-producing medium adjuster 91 is described.This cold-producing medium adjuster 91 consists of the closed container 92 with specified volume, side at this container 92, connection is formed with the cold-producing medium inflow section 96 flowed into from the cold-producing mediums of senior side spray outlet 28 ejections of compressor 11, and is connected with high pressure ejection pipe arrangement 42 (senior side spray exports 28 sides).In addition, in the upper surface of container 92, be communicated with the cold-producing medium outflow section 97 that is formed with the cold-producing medium outflow made in container 92, and be connected with high pressure ejection pipe arrangement 42 (gas cooler 46 sides).

And, being separated wall 93 in this container 92 and dividing up and down, its downside is that cold-producing medium flows into chamber 94, upside is cold-producing medium delivery chamber 95.Cold-producing medium flows into chamber 94 and is connected to form with above-mentioned cold-producing medium inflow section 96, and cold-producing medium delivery chamber 95 and cold-producing medium outflow section 97 are connected to form.And 94 sides are provided with suction inlet 98 in the cold-producing medium inflow chamber of partition wall 93, this suction inlet 98 is connected to form with the suction path 99 be formed on partition wall 93.

Cold-producing medium delivery chamber 95 sides at this suction path 99 are provided with the top that is positioned at container 92 and the check-valves consisted of leaf valve 90.This check-valves 90 take from cold-producing medium flow into chamber 94 sides towards the direction of cold-producing medium delivery chamber 95 for forward (with the senior side spray from compressor 11, exporting 28 directions towards gas cooler 46 (separator 44) for forward).And, supporting mass 90A and this check-valves 90 vacate predetermined distance and be fixed on this check-valves 90 near.

And, be provided with the oil return pipe 86 be connected with above-mentioned compressor 11 in the container bottom of this container 92.This oil return pipe 86 is connected with above-mentioned oil return circuit 73, with container 92 is interior, is communicated with thus.

According to above structure, from the cold-producing mediums of senior side spray outlet 28 ejections of compressor 11, via high temperature ejection pipe arrangement 42 and from the cold-producing medium inflow section 96 of cold-producing medium adjuster 91, to cold-producing medium, flow into the interior inflow in chamber 94.Here, because cold-producing medium flows into the volume that chamber 94 has regulation, therefore can realize equalization by the soundproof effect Absorbing Fluctuation.

The cold-producing mediums that cold-producing medium flows in chamber 94 pass through in sucking path 99 via suction inlet 98, and via take from cold-producing medium flow into chamber 94 towards cold-producing medium delivery chamber 95 sides as check-valves 90 forward to the interior ejection of cold-producing medium delivery chamber 95.Check-valves 90 consists of leaf valve as mentioned above, therefore can eliminate noise and produce.

And the cold-producing medium in cold-producing medium delivery chamber 95 sprays to the ejection of the high temperature towards gas cooler 46 pipe arrangement 42 via cold-producing medium outflow section 97.

Here, be provided with in the container 92 of cold-producing medium adjuster 91 that to take from senior side spray outlet 28 directions towards gas cooler 46 (separator 44) of compressor 11 be check-valves 90 forward, therefore, in the situation that compressor 11 stops, spray the check-valves 90 of the cold-producing medium adjuster 91 of pipe arrangement 42 by being arranged at high pressure, also make the high-pressure refrigerant of gas cooler 46 sides not be communicated with compressor 11 sides.Therefore, even stop and causing in the situation that closed container 12 inner high voltage sides become with middle swaging all presses in the running of compressor 11, near the on high-tension side pressure of the refrigerant loop 1 till also can maintaining from check-valves 90 to the main throttle mechanism 62A, the 62B that are located at evaporimeter 63A, 63B.

That is,, in the situation that this check-valves 90 is not set, in the compressor 11 stopped, high-pressure side and medium voltage side form all and press.On the other hand, in closed container 12, with regard to low-pressure side and medium voltage side, only low-pressure side is immersed in oil, therefore can all not press easily.But, when starting compressor 11, because the pressure differential in refrigerant loop 1 is large, therefore, need the stipulated time till refrigerant loop 1 integral body is all pressed, thereby cause the startability variation.

Yet, in the present embodiment, after stopping compressor 11, maintain the on high-tension side pressure of refrigerant loop 1 by check-valves 90, can improve thus the startability of described compressor 11.In addition, due to interior whole uneven pressure of refrigerant loop 1, therefore can realize the high efficiency of refrigerating circulatory device.

In addition, as in this embodiment, be provided with many, be two compressors 11,11 in this case at refrigerating plant R, in the situation that two compressors 11,11 connect mutually side by side, possess the positions before high pressure ejection pipe arrangement 42,42 interflow that the cold-producing medium adjuster 91 of above-mentioned check-valves 90 and compressor 11,11 separately be arranged on each compressor 11,11 accordingly.Thus, can append the compressor of many structures and make their runnings, thereby can improve volume controlled.

As mentioned above, be provided with the capacity that the container 92 of the cold-producing medium adjuster 91 of check-valves 90 has regulation, therefore can also play from the function of the separator of cold-producing medium separating oil.The oil that accumulates in the bottom of this container 92 can successfully return to corresponding respectively compressor 11,11 via the oil return pipe 86 of being located at this bottom.

(H) defrosting of evaporimeter is controlled

As mentioned above, each showcase unit 5A, 5B are connected side by side with refrigerant piping 7 and 9 respectively.Be connected with respectively filter 61A, 61B, main throttle mechanism 62A, 62B, evaporimeter 63A, 63B in turn at the cabinet side refrigerant piping 60A, the 60B that link each showcase unit 5A, 5B and refrigerant piping 7 and refrigerant piping 9.

And, be connected with the first communicating pipe 64A of the outlet side of the evaporimeter 63A that is communicated with this side and the entrance side of the main throttle mechanism 62B of evaporimeter 63B corresponding to the opposing party at the outlet side of a side evaporimeter 63A, at this first communicating pipe 64A, be provided with magnetic valve (valve gear) 65A.In addition, be connected with the second communicating pipe 64B of the outlet side of the evaporimeter 63B that is communicated with this opposing party and the entrance side of the main throttle mechanism 62A of evaporimeter 63A corresponding to a described side at the outlet side of the opposing party's evaporimeter 63B, be provided with magnetic valve (valve gear) 65B in this second communicating pipe 64B.In addition, in the present embodiment, main throttle mechanism 62A, 62B consist of electric expansion valve, but in addition, also can be by capillary, make the bypass pipe of this capillary bypass, magnetic valve form throttle mechanism.

In addition, in the downstream of the current divider with each communicating pipe 64A, 64B shunting, be provided with magnetic valve (valve gear) 66A and 66B, described each communicating pipe 64A, 64B are connected with each cabinet side refrigerant piping 60A, the evaporimeter 63A of 60B or the outlet side of 63B.Form the stream controlling organization by above-mentioned magnetic valve 65A, 65B, 66A, 66B.

On the other hand, as mentioned above, be provided with the gas cooler bypass circulation 71 of gas cooler 46 bypass that make to form refrigerant loop 1.Be provided with magnetic valve 72 in this gas cooler bypass circulation 71.And, each magnetic valve 65A, 65B, 66A, 66B, 72 and main throttle mechanism 62A, 62B control and open and close by above-mentioned control device C.

According to above structure, at first, the defrosting of a side evaporimeter 63A is controlled and described.While carrying out a side the defrosting of evaporimeter 63A, control device C controls above-mentioned stream controlling organization, makes from evaporimeter 63A cold-producing medium out flow to the first communicating pipe 64A, and from evaporimeter 63B, cold-producing medium out returns to compressor 11.That is, make the main throttle mechanism 62A standard-sized sheet corresponding with this evaporimeter 63A, open magnetic valve 65A, the magnetic valve 66B of the first communicating pipe 64A.Close magnetic valve 65B and the magnetic valve 66A of the second communicating pipe 64B.In addition, in the situation that form main throttle mechanism 62A by capillary, the bypass pipe that makes this capillary bypass, magnetic valve, open the magnetic valve of bypass pipe.

Thus, arrive cabinet side refrigerant piping 60A from the high-temperature high-pressure refrigerant of compressor 11 ejection through gas cooler 46, waste heat recovery heat exchanger 70, Intermediate Heat Exchanger 80, refrigerant piping 7, directly flow in a side evaporimeter 63A with the form of gas refrigerant through the main throttle mechanism 62A that forms standard-sized sheet.Due to shut electromagnetic valve 66A in advance and open magnetic valve 65A, therefore the cold-producing medium (being gas refrigerant while carrying out gas circulation) that the defrosting by this evaporimeter 63A is liquefied is through the first communicating pipe 64A, and the entrance side of corresponding main throttle mechanism 62B flows into to the evaporimeter 63B with the opposing party.

Therefore, the cold-producing medium main throttle mechanism 62B puffing corresponding by the evaporimeter 63B with the opposing party be liquefied because of the defrosting of a side evaporimeter 63A, and evaporate in the opposing party's evaporimeter 63B.Thus, can eliminate the unfavorable condition that cold-producing medium that the defrosting because of a side evaporimeter 63A is liquefied directly returns to compressor 11.

When the defrosting of the evaporimeter 63B that carries out the opposing party, control device C is following controls above-mentioned stream controlling organization, makes from evaporimeter 63B the second communicating pipe of refrigerant flow direction 64B out, and from evaporimeter 63A, cold-producing medium out returns to compressor 11.That is, main throttle mechanism 62B standard-sized sheet that will be corresponding with this evaporimeter 63B, open magnetic valve 65B, the magnetic valve 66A of the second communicating pipe 64B.Close magnetic valve 65A and the magnetic valve 66B of the second communicating pipe 64A.

Thus, arrive cabinet side refrigerant piping 60B from the high-temperature high-pressure refrigerant of compressor 11 ejection through gas cooler 46, waste heat recovery heat exchanger 70, Intermediate Heat Exchanger 80, refrigerant piping 7, directly flow in the opposing party's evaporimeter 63B with the form of gas refrigerant through the main throttle mechanism 62B that forms standard-sized sheet.Due to shut electromagnetic valve 66B and open magnetic valve 65B, the entrance side of cold-producing medium (being gas refrigerant while carrying out gas circulation) the corresponding main throttle mechanism 62A through the evaporimeter 63A of the second communicating pipe 64B Xiang Yuyi side therefore be liquefied because of the defrosting of this evaporimeter 63B flows into.Therefore, the cold-producing medium main throttle mechanism 62A puffing corresponding by the evaporimeter 63A with a side be liquefied because of the defrosting of the opposing party's evaporimeter 63B, and evaporate in a side evaporimeter 63A.

Like this, in the refrigerating plant R that possesses a plurality of evaporimeter 63A, 63B, evaporimeter by utilizing the opposing party carries out evaporation process to the cold-producing medium because defrosting is liquefied mutually, can eliminate the unfavorable condition that because of the defrosting cold-producing medium after liquefying directly returns to compressor 11.In addition, can realize with simple structure the defrosting of above-mentioned evaporimeter 63A, 63B.

In addition, in the present embodiment, for example understand the evaporimeter 63A of two refrigerator unit 5A, 5B, the defrosting of 63B, but in the situation that further increase the quantity of evaporimeter, also can utilize different evaporimeters to carry out evaporation process to the cold-producing medium mutually liquefied because of defrosting, can obtain effect of the present invention thus.

In addition, in the present embodiment, control device C is in the situation that the low temperature that is regulation by the detected temperature of extraneous gas temperature sensor 56 is opened the magnetic valve 72 of being located at gas cooler bypass circulation 71 when this defrosting.The high cold-producing medium of the temperature of having avoided gas cooler 46 (having passed through gas cooler bypass circulation 71) that thus, can make to become supercritical steam cycle flows into to the evaporimeter defrosted.

Thus, when externally temperature is low etc., in the situation that the temperature of the cold-producing medium flowed into to the evaporimeter defrosted is low, can supply with the cold-producing medium of higher temperature, realize defrosting efficiently.

In addition, due to the defrosting that can realize having utilized used heat, therefore do not need the special heating arrangements such as heater, can realize energy-conservation.In addition, owing to can avoid the heater energising when defrosting, therefore can cut down peak value electric power.

As shown in this embodiment, in the situation that used carbon dioxide as cold-producing medium, due to the ejection temperature that can improve from compressor 11, therefore can improve the defrost performance of evaporimeter.

Claims (2)

1. a refrigerating plant, it by compressing mechanism, gas cooler, throttle mechanism, evaporimeter, forms refrigerant loop and high-pressure side becomes supercritical pressure, and this refrigerating plant is characterised in that to possess:

Bypass circulation, it is communicated with middle nip territory and the low-pressure side zone of described refrigerant loop;

Valve gear, it is arranged in this bypass circulation;

Controlling organization, it controls this valve gear,

This controlling organization utilized described valve gear to open the stream of described bypass circulation before the operating frequency of described compressing mechanism regulation from start to rising to,

High pressure ejection pipe arrangement at the compressor as described compressing mechanism is provided with the cold-producing medium adjuster,

Be provided with in the container of described cold-producing medium adjuster that to take from the senior side spray outlet of described compressor be check-valves forward towards the direction of described gas cooler.

2. refrigerating plant according to claim 1, is characterized in that,

Use carbon dioxide as described cold-producing medium.

Images