CN102109239B - Refrigerating apparatus - Google Patents

Abstract

An object of the present invention is to keep an appropriate amount of a refrigerant to be circulated through a refrigerant circuit and prevent an overload operation of compression means due to high pressure abnormality in a refrigerating apparatus which obtains a supercritical pressure on a high pressure side. The refrigerating apparatus (R) obtains the supercritical pressure on the high pressure side. In the refrigerating apparatus (R), a refrigerant circuit (1) is formed on the high pressure side by a compressor (11), a gas cooler (46), main reducing means (62A, 62B), evaporators (63A, 63B). The refrigerating apparatus (R) comprises an oil separator (44) for separating the oil from the refrigerant sprayed from the compressor (11), an oil return circuit (73), an oil cooler (74), an oil bypass circuit (78),an electromagnetic valve (79) and a control means (C) for controlling these valves to collect a refrigerant circulated through the refrigerant circuit in the tank and discharging the refrigerant to the refrigerant circuit.

Description

Refrigerating plant

Technical field

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

Background technology

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

Patent documentation 1: the special fair 7-18602 communique of Japan

If circulate in refrigerant loop with cold-producing medium with the oil that cold-producing medium sprays from compressing mechanism, then oil lodges in interior grade of heat exchanger in the refrigerant loop and is difficult to return to compressor.Therefore, return to compressing mechanism in order to make this oil, in the cold-producing medium bleed pipe of compressing mechanism, separator is set.The oil return loop that is provided with oil cooler is connected with separator, and the oil that separates with cold-producing medium is cooled off by turning back to compressing mechanism by the oil return loop by separator.

Here, if oil cooler is arranged in the wind path that is provided with gas cooler and by same air blast they are carried out air cooling, then when low extraneous gas temperature, produce the interior cold excessively problem of oil of oil cooler, thus, cold-producing medium becomes and dissolves in the oil easily.Become heavy owing to dissolving in the oil viscosity rising that cold-producing medium is arranged, therefore have the problem of returning to compressing mechanism of returning deterioration of efficiency.

Summary of the invention

The present invention proposes in order to solve prior art problems, its purpose is to provide a kind of refrigerating plant, even the unfavorable condition that this refrigerating plant also can prevent from dissolving in cold-producing medium under the situation in oil when low extraneous gas temperature etc., thereby realize that oil successfully turns back to compressing mechanism.

In order to address the above problem, a first aspect of the present invention provides a kind of refrigerating plant, it constitutes refrigerant loop by compressing mechanism, gas cooler, throttle mechanism, evaporimeter and the high-pressure side becomes supercritical pressure, described refrigerating plant is characterised in that, possess: separator, it separates the oil from the cold-producing medium of compressing mechanism ejection; The oil return loop, it makes the oil in this separator turn back to compressing mechanism; Oil cooler, it is arranged in this oil return loop; The oil bypass loop, it makes this oil cooler bypass; Valve gear, it is arranged in this oil bypass loop; Controlling organization, it controls this valve gear, makes the oil in the separator turn back to compressing mechanism without oil cooler.

On the basis aspect above-mentioned, a second aspect of the present invention is characterised in that gas cooler and oil cooler are arranged in the same wind path, by the air blast air cooling.

On the basis of above-mentioned each side, a third aspect of the present invention is characterised in that, controlling organization is opened the stream in oil bypass loop when externally gas temperature is lower than setting by valve gear.

On the basis of above-mentioned first aspect or second aspect, a fourth aspect of the present invention is characterised in that, controlling organization is opened the stream in oil bypass loop by valve gear when the temperature of separator is lower than setting.

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

The invention effect

According to the present invention, in refrigerating plant, constitute refrigerant loop and the high-pressure side becomes supercritical pressure by compressing mechanism, gas cooler, throttle mechanism, evaporimeter, described refrigerating plant possesses: separator, and it separates the oil from the cold-producing medium of compressing mechanism ejection; The oil return loop, it makes the oil in this separator turn back to compressing mechanism; Oil cooler, it is arranged in this oil return loop; The oil bypass loop, it makes this oil cooler bypass; Valve gear, it is arranged in this oil bypass loop; Controlling organization, it controls this valve gear so that the oil in the separator turns back to compressing mechanism without oil cooler, even when forming the situation of oil intrusion oil cooler thus, also can make the oil in the separator turn back to compressing mechanism without oil cooler via the oil bypass loop by opening valve gear.Thus, can make oil successfully turn back to compressing mechanism.

As a second aspect of the present invention, gas cooler and oil cooler be arranged in the same wind path and during by the air blast air cooling, the temperature of oil cooler reduces owing to the running of this air blast, cold-producing medium dissolves in the oil easily, but pass through controlling organization, open the valve gear in oil bypass loop, thereby the oil in the separator is successfully returned to compressing mechanism via the oil bypass loop without oil cooler.Thus, especially effective under the situation of the adjustment that can not carry out the air cooling amount.

According to a third aspect of the invention we, on the basis in every respect, controlling organization is when externally gas temperature is lower than setting, open the stream in oil bypass loop by valve gear, prevent thus that cold-producing medium from dissolving in the oil and viscosity rises, thereby can make the oil in the separator turn back to compressing mechanism via the oil bypass loop of oil cooler being walked around (making a circulation) reliably.

According to a forth aspect of the invention, on the basis of above-mentioned first aspect or second aspect, controlling organization is when the temperature of separator is lower than setting, utilize valve gear to open the stream in oil bypass loop, prevent thus that cold-producing medium from dissolving in the oil and viscosity rises, thereby can make the oil in the separator turn back to compressing mechanism via the oil bypass loop that oil cooler is walked around reliably.

As a fifth aspect of the present invention, using under the situation of carbon dioxide as cold-producing medium, can make oil successfully turn back to compressing mechanism and can improve refrigerating capacity effectively by above-mentioned aspect, thereby can realize the raising of performance.

Description of drawings

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

Fig. 2 is the block diagram of control device.

The figure of the trend of Fig. 3 target high pressure HPT that to be expression determined by extraneous gas temperature and 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 rotation compressing members

20 second rotation compressing members

22 rudimentary side draught entrances

24 rudimentary side ejiction openings

26 senior side draught entrances

28 senior side ejiction openings

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 arrangement

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 detecting 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 loops

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 first stream

80B 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 (first switching mechanism with throttling function)

103 second connected loops

104 magnetic valves (second switching mechanism)

105 third connecting loops

106 magnetic valves (the 3rd switching mechanism)

The specific embodiment

Below, with reference to the description of 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 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 the kind of refrigeration cycle that constitutes regulation by refrigerant piping 7 and 9.

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

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 constituted by steel plate, configuration be accommodated in this closed container 12 the inner space upside as the electric element 14 of driving element and be configured in the downside of this electric element 14 and rotary compressor structure portion that the rotating shaft 16 by electric element 14 drives is made of first (rudimentary side) rotation compressing member (first compressing member) 18 and second (senior side) rotation compressing member (second compressing member) 20.

The low pressure refrigerant that first 18 pairs of the compressing members of rotation suck compressor 11 via refrigerant piping 9 from the low-pressure side of refrigerant loop 1 compresses and it is pressed in the middle of boosting to and with its ejection, the second rotation compressing member 20 further suck and compression ejection by 18 compressions of the first rotation compressing member in the middle of the cold-producing medium of pressing, and make it boost to high pressure and to the high-pressure side ejection of refrigerant loop 1.Compressor 11 is compressors of changeable frequency type, can control the rotating speed of the first rotation compressing member 18 and the second rotation compressing member 20 by the operating frequency of change electric element 14.

Be formed with the rudimentary side draught entrance 22 and the rudimentary side ejiction opening 24 that are communicated with the first rotation compressing member 18 in the side of the closed container 12 of compressor 11, rotate senior side draught entrance 26 and the senior side ejiction opening 28 that compressing member 20 is communicated with second.Be connected with cold-producing medium ingress pipe 30 respectively at each compressor 11,11 rudimentary side draught entrance 22,22, each cold-producing medium ingress pipe 30 is connected at their upstream side interflow and with refrigerant piping 9.

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

Then, press ejection pipe arrangement 36,36 in the middle of each compressor 11 of the refrigerant gas of pressing in the middle of in ejection closed container 12,11 rudimentary side ejiction opening 24,24 are connected with respectively, press ejection pipe arrangement 36 to be connected with an end of intercooler 38 at their interflow, downstream in the middle of each.38 pairs of middle cold-producing mediums of pressing from 18 ejections of the first rotation compressing member 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 with each compressor 11,11 senior side draught entrance 26,26 and is connected.

The refrigerant gas of middle pressure (MP) that sucks the middle splenium of the second rotation compressing member 20 by senior side draught entrance 26 is carried out the refrigerant gas that second level compression becomes HTHP (HP: the supercritical pressure about 12MPa under the operating condition) usually by this second rotation compressing member 20.

And, be connected with high pressure ejection pipe arrangement 42,42 respectively at the senior side ejiction opening 28,28 of hyperbaric chamber side of being located at each compressor 11,11 the second rotation compressing member 20, each high pressure ejection pipe arrangement 42,42 is connected with refrigerant loop 7 via the Intermediate Heat Exchanger 80 of separator 44, gas cooler 46, the waste heat recovery heat exchanger 70 that describes in detail in the back and formation separating cycle at their interflow, downstream.

46 pairs of ejection cold-producing mediums from the high pressure of compressor 11 ejections of gas cooler cool off, and are provided with the gas cooler air blast 47 that this gas cooler 46 is carried out 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 that describes in detail in the back, and all is provided in the same wind path 45.In this 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 addition, senior side ejiction opening 28,28 be provided with detection from the high-pressure sensor (high-pressure testing agency) 48 of the ejection pressure of the cold-producing mediums of the second rotation compressing member 20,20 ejections, detect the ejection temperature sensor (ejection temperature testing organization) 50 of ejection refrigerant temperature and possess with from the senior side ejiction opening 28 of compressor 11 towards the direction of gas cooler 46 (oil eliminator 44) the cold-producing medium adjuster 91 for forward check-valves 90.In addition, this cold-producing medium adjuster 91 is described in detail in the back.

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

Refrigerating plant R possesses control device (controlling organization) C that is made of general microcomputer.This control device C is connected with various sensors at input side as shown in Figure 2, 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) refrigerant amount adjustment control

Next, the refrigerant amount adjustment control to the refrigerant loop 1 of the refrigerating plant R of present embodiment describes.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, be connected with refrigerant amount adjusting tank 100 via first connected loop 101 in the present embodiment.This refrigerant amount adjusting tank 100 has the volume of regulation, is connected with first connected loop 101 on these case 100 tops.In this first connected loop 101, be provided with the electric expansion valve 102 of conduct first switching mechanism with throttling function.Need to prove that the switching mechanism with throttling function is not limited to this, the mechanism that is made of for example capillary and magnetic valve (open and close valve) for example also can be set as throttle mechanism in first connected loop 101.

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 at this refrigerant amount adjusting tank 100.In the present embodiment, the other end of second connected loop 103 as the example in middle nip territory and with the outlet side of the intercooler 38 of refrigerant loop 1 in the middle of press suction line 40 to be communicated with.In this second connected loop 103, be provided with the magnetic valve 104 as second switching mechanism.

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

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

(A-1) refrigerant-recovery action

Below, action describes to the refrigerant-recovery of refrigerant loop 1.Whether the detected pressures of control device C judging unit outlet side pressure sensor 58 surpasses the recovery threshold value of regulation; perhaps, whether the detected pressures of judging this unit outlet side pressure sensor 58 surpasses the recovery protection value of the regulation lower than above-mentioned recovery threshold value and above-mentioned gas cooler and whether reaches maximum with the rotating speed of air blast 47.

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

Thus; control device C is under the situation of 9MPa in the detected pressures of unit outlet side pressure sensor 58 above reclaiming threshold value; perhaps; reclaiming below the threshold value in detected pressures but surpassing that to reclaim the protection value be 8Mpa; and the above-mentioned gas cooler reaches under the situation of peaked 800rpm with the rotating speed of air blast 47; the gas refrigerant that is judged as because of the surplus in the 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 (first switching mechanism) 102 and magnetic valve (second switching mechanism) 104 under the state of closing magnetic valve (the 3rd switching mechanism) 106.Thus, from the high-temperature high-pressure refrigerant of compressor 11,28 ejections of 11 senior side ejiction opening via separator 44 by gas cooler 46, waste heat recovery heat exchanger 70, Intermediate Heat Exchanger 80 coolings, flow in the refrigerant amount adjusting tank 100 via first connected loop 101 that is provided with the electric expansion valve 102 that partially opens afterwards.

At this moment, by opening magnetic valve 104, can refrigerant amount adjusting tank 100 interior pressure be discharged outside case via second connected loop 103 in the top that is communicated with refrigerant amount adjusting tank 100 and the middle nip territory of refrigerant loop 1.Therefore, even under the situation of the gas circulation running that the cold-producing medium in the refrigerant loop 1 does not liquefy when externally gas temperature uprises etc., also can reduce the pressure in the case 100 and make the cold-producing medium liquefaction that flows in this case and accumulate in this case 100.That is, be reduced to below the supercritical pressure by the pressure in the refrigerant amount adjusting tank 100, cold-producing medium becomes the zone of saturation from gas zones thus, thereby can guarantee liquid level.

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

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

In addition; in the present embodiment; reclaimed by unit outlet side pressure sensor 58 detected on high-tension side pressure below the threshold value but surpass the recovery protection value of regulation and be under the situation of 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 can also consider the operating condition of this air blast 47, thereby can prevent that the efficient that state continuance that the high-pressure side because of refrigerant loop 1 uprises unusually causes from reducing.

(A-2) cold-producing medium keeps action

On the other hand; control device C judges whether by unit outlet side pressure sensor 58 detected on high-tension side pressure be below the 8MPa in reclaiming protection value, present embodiment; be lower than under the situation that reclaims the protection value, the end refrigerant-recovery is moved and is shifted to cold-producing medium and keeps action.Keep in the action at this cold-producing medium, control device C keeps the state of closing magnetic valve (the 3rd switching mechanism) 106, close magnetic valve (second switching mechanism) 104, and the aperture of electric expansion valve (first switching mechanism) 102 is maintained aperture in the previous refrigerant-recovery action.

Need to prove, also can make the aperture of above-mentioned electric expansion valve 102 less than the aperture in the refrigerant-recovery action.Thus, by closing magnetic valve 104, can under the effect of the pressure in the zone, high-pressure side of refrigerant loop 1, keep liquid level in the refrigerant amount adjusting tank 100 via the electric expansion valve of opening 102.Therefore, the fluid-tight in the refrigerant amount adjusting tank 100 can be avoided, security can be guaranteed.Thus, can suitably keep circularly cooling dosage in the refrigerant loop 1.

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

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

And; what whether the detected pressures of control device C judging unit outlet side pressure sensor 58 was lower than the regulation lower than above-mentioned recovery protection value (in this case for about 8MPa) emits threshold value (in the present embodiment for about 7MPa); perhaps, whether the detected pressures of judging 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.Need to prove that in the present embodiment, as an example, the setting of this regulation is peaked about 3/8, that is, when peak was 800rpm, the setting of this regulation was about 300rpm.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 lower than in the detected pressures of unit outlet side pressure sensor 58 and emits under the situation that threshold value is 7MPa; perhaps; become that to reclaim the protection value be below the 8Mpa and the above-mentioned gas cooler becomes with the rotating speed of air blast 47 under the situation below the setting (being 300rpm in this case) of regulation in detected pressures; be judged as the lack of refrigerant in the refrigerant loop 1, carry out cold-producing medium and emit action.

Emit in the action at this cold-producing medium, control device C closes electric expansion valve (first switching mechanism) 102 and magnetic valve (second switching mechanism) 104, and opens magnetic valve (the 3rd switching mechanism) 106.Thus, accumulate in the 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 emit to refrigerant loop 1.Therefore, with with cold-producing medium in that 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 the refrigerant amount adjusting tank 100 be emitted to refrigerant loop 1, refrigerating plant is turned round with high efficiency.

(A-4) cold-producing medium keeps action

Afterwards; whether control device C judgement is become by unit outlet side pressure sensor 58 detected on high-tension side pressure is reclaimed more than the protection value (being 8MPa in the present embodiment), and the end cold-producing medium is emitted action and shifted to cold-producing medium as mentioned above and keeps action under the situation that surpasses recovery protection value.Afterwards; high side pressure according to refrigerant loop 1; carrying out this refrigerant-recovery action-cold-producing medium repeatedly 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 high voltage protective reliably 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 that the efficient that state continuance that the high-pressure side because of refrigerant loop 1 uprises unusually causes from reducing.

In addition, in the present embodiment, 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, under the situation that compressor 11,11 running stop, 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 startings in the refrigerant loop 1 can realize suitable high side pressure according to the on high-tension side pressure based on the compressor 11 that turns round.

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

(B) separating cycle

Next, the separating cycle to the refrigerating plant R in the present embodiment describes.Among the refrigerating plant R in the present embodiment, constitute kind of refrigeration cycle by each compressor 11,11 the first rotation compressing member (rudimentary side) 18, intercooler 38, the interflow device 81 as converging device that makes the mobile interflow of two kinds of fluids, each compressor 11,11 the second rotation compressing member (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, 63B.

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

Among Fig. 1, major loop is the refrigerant loop of the ring-type that is made of first rotation compressing member 18, the intercooler 38, interflow device 81, the second rotation compressing member 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 is represented 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 that is flowed in subsidiary loop by above-mentioned current divider 82 shuntings is reduced pressure.Intermediate Heat Exchanger 80 is to carry out by the heat exchanger of first cold-producing medium stream in the auxiliary throttle mechanism 83 post-decompression subsidiary loops with the heat exchange of being flowed by second cold-producing medium after current divider 82 shuntings.In this Intermediate Heat Exchanger 80, the first stream 80A that the second stream 80B that second cold-producing medium stream is flowed and above-mentioned first cold-producing medium stream are flowed is can carry out the setting that concerns of heat exchange, because the second stream 80B by this Intermediate Heat Exchanger 80, thereby first cold-producing medium stream that the second cold-producing medium stream can be flowed in the first stream 80A cools off, and therefore can reduce the specific enthalpy of evaporimeter 63A, 63B.

Above-mentioned control device C is connected with ejection temperature sensor (ejection temperature testing organization) 50, unit outlet side pressure sensor (unit outlet side pressure detecting 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 as shown in Figure 2.

Ejection temperature sensor 50 is arranged at compressor 11,11 senior side ejiction opening 28, for detection of the ejection temperature from the cold-producing medium of the second rotation compressing member, 20 ejections.Unit outlet side pressure sensor 58 is positioned at the downstream of refrigerant amount adjusting tank 100, for detection of the pressure towards the cold-producing medium of showcase unit 5A, 5B.Low-pressure sensor 32 is positioned at the low-pressure side of refrigerant loop 1, be positioned at the downstream of each evaporimeter 63A, 63B in the present embodiment, and be located at and compressor 11,11 rudimentary side draught entrance 22,22 refrigerant pipings that are connected 9, for detection of the suction pressure towards the cold-producing medium of 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 at the subsidiary loop of separating cycle in the present embodiment, detects the pressure through the stream of first cold-producing medium behind 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) of the cold-producing medium that comes out from this gas cooler 46.Unit outlet temperature sensor 54 is located at the outlet side of the Intermediate Heat Exchanger 80 that is connected with refrigerant piping 7, for detection of unit outlet temperature (LT).Unit inlet temperature sensor 34 is located at the refrigerant piping 9 that is connected with the rudimentary side draught entrance 22 of compressor 11, for detection of the inlet temperature towards the cold-producing medium of this cold-producing medium ingress pipe 30.And, be connected with the auxiliary throttle mechanism 83 that constitutes this separating cycle at outlet side.Should assist the aperture of throttle mechanism 83 by Step-motor Control.

Below, the aperture control of assisting throttle mechanism 83 is 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 to make the operational ton of the valve opening increase of assisting throttle mechanism 83 according to the first following controlled quentity controlled variable, second controlled quentity controlled variable, the 3rd controlled quentity controlled variable.

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

First controlled quentity controlled variable (DTcont) obtains according to the ejection refrigerant temperature DT of compressor 11.Control device C judges whether be higher than setting DT0 by above-mentioned ejection temperature sensor 50 detected temperature DT, DT is higher than under the situation of setting DT0 in this ejection refrigerant temperature, sets for towards the controlled quentity controlled variable of the directive effect of the aperture increase that makes auxiliary throttle mechanism 83.This setting DT0 is set at the low slightly temperature (being+95 ℃ as an example) of critical temperature (being+100 ℃ as an example) than the suitable running that can realize compressor 11, under 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 controls so that compressor 11 does not reach critical temperature.

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

Need to prove, 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 in advance experimentally, determine suitable intermediate pressure value according to the tables of data of constructing thus.

In addition, in the present embodiment, the suitable intermediate pressure value of being obtained by high side pressure HP, low-pressure lateral pressure LP and the pressure MP in middle nip territory relatively, thereby definite second controlled quentity controlled variable (MPcont), but be not limited thereto, for example, can be in the following way.Namely, according to obtaining overcompression decision content MPO by the pressure MP in the middle nip territory of middle pressure pressure sensor 49 detected refrigerant loops 1 with by the low-pressure lateral pressure LP of low-pressure lateral pressure sensor 32 detected refrigerant loops 1, judge 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, be lower than under the situation of high side pressure HP at overcompression decision content MPO, towards the directive effect of the aperture increase that makes auxiliary throttle mechanism 83.By making this second controlled quentity controlled variable be reflected to the aperture control of auxiliary throttle mechanism 83, can suitably keep the pressure MP in high side pressure HP, middle nip territory, the pressure differential of low-pressure lateral pressure LP thus, 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 for suitableization of the refrigerator temperature LT that realizes coming out from second stream of middle heat exchanger 80.In the present embodiment, control device C judge by the detected temperature GCT through the cold-producing medium behind the gas coolers 46 of gas cooler exit temperature sensor 52 with by poor (GCT-LT) of the detected temperature LT through Intermediate Heat Exchangers second cold-producing medium stream after 80s of unit outlet temperature sensor 54 whether less than setting SP, under the situation of little and setting SP, towards the mode effect of the aperture increase that makes auxiliary throttle mechanism 83.

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

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

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

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

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

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

Here, setting TDT is set under following two kinds of situations different, that is, these two kinds of situations are high side pressure HP in the situation of the supercritical range of this cold-producing medium and the high side pressure HP situation in the zone of saturation.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 the zone of saturation.And, under situation about being judged as at supercritical range, set setting TDT low, under situation about being judged as in the zone of saturation, set setting TDT high.In the present embodiment, setting TDT is set at 10 ℃ when supercritical range, is set at 35 ℃ when the zone of saturation.

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

In the refrigerating plant R of the present embodiment that possesses separating cycle as described above, can be with the cold-producing medium shunting after gas cooler 46 heat radiations, and by being cooled off second cold-producing medium stream by the first cold-producing medium stream behind 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 improve performance effectively.In addition, because the stream of first cold-producing medium after the shunting returns the second rotation compressing member 20 (middle splenium) from the senior side draught entrance 26 of compressor 11, therefore the amount minimizing of second cold-producing medium stream from the rudimentary side draught entrance 22 suctions first rotation compressing member 18 (low voltage section) of compressor 11 is used for being compressed to from low pressure the compression work amount minimizing of the middle first rotation compressing member 18 (rudimentary portion) of pressing.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 first cold-producing medium flows and second cold-producing medium flows that flows in Intermediate Heat Exchanger 80.That is, if the amount of first cold-producing medium stream is too much, the quantity not sufficient of second cold-producing medium stream that then finally evaporates among evaporimeter 63A, the 63B, hence one can see that, on the contrary if the amount of first cold-producing medium stream is very few, then the effect of separating cycle weakens.On the other hand, the pressure that is flowed by auxiliary throttle mechanism 83 post-decompression first cold-producing mediums is the intermediate pressure of refrigerant loop 1, and the amount of controlling first cold-producing medium stream is this intermediate pressure of control.

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

Thus, can remain on below the setting DT0 by the temperature DT that first controlled quentity controlled variable will spray cold-producing medium, can the intermediate pressure MP of refrigerant loop 1 suitably be changed by second controlled quentity controlled variable, can suitably keep the pressure differential of low-pressure lateral pressure LP, intermediate pressure MP, high side pressure HP thus.In addition, can reduce the temperature LT that flows through Intermediate Heat Exchanger second cold-producing medium after 80s 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 is under the situation of supercritical range at high side pressure HP, improve setting SP and reduce setting TDT, and be at high side pressure HP under the situation of zone of saturation, reduce setting SP and improve setting TDT, can be distinguished into situation that high side pressure HP is in the situation of supercritical range and is in the zone of saturation thus and change the setting SP of the 3rd controlled quentity controlled variable and first controlled quentity controlled variable and TDT and control.

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

Need to prove, 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: second controlled quentity controlled variable that makes above-described embodiment under the situation of the high side pressure HP that is lower than refrigerant loop 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 towards second controlled quentity controlled variable of the directive effect that increases the aperture of assisting throttle mechanism, add up to first to the 3rd controlled quentity controlled variable, determine the operational ton of the valve opening of auxiliary throttle mechanism thus.

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

(C) waste heat recovery heat exchanger

Next, the waste heat recovery heat exchanger 70 that the refrigerating plant R of present embodiment is adopted describes.The waste heat recovery heat exchanger 70 of present embodiment is to carry out through gas cooler 46 and by the heat exchanger of second cold-producing medium stream after current divider 82 shuntings with the heat exchange of the carbon dioxide coolant (Waste Heat Recovery medium) of the heat pump unit that constitutes not shown hot-water supply.The hot-water supply of present embodiment is made 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 the refrigerant loop that tubulose forms; Water among the thermal storage water tank is made its water loop of returning the thermal storage water tank by after the water heat exchanger heating, and the evaporimeter of this heat pump unit is made 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 cold-producing medium stream in the separating cycle is flowed and Waste Heat Recovery medium stream 70B are can carry out the setting that concerns of heat exchange, the cold-producing medium of the heat pump unit that utilization is flowed in the Waste Heat Recovery medium stream 70B of this waste heat recovery heat exchanger 70 passes through, and is cooled through the second cold-producing medium stream behind the gas cooler 46 in refrigerant flow path 70A thus.

Here, in the present embodiment, in the refrigerant flow path 70A of waste heat recovery heat exchanger 70, flow and come out and enter second cold-producing mediums stream before the Intermediate Heat Exchanger 80 that constitutes above-mentioned separating cycle from gas cooler 46.Thus, the extraneous gas Temperature Influence is little, can be recovered among the refrigerant flow path 70A used heat of the cold-producing medium that flows effectively and be used in the heating of the cold-producing medium that in constituting the Waste Heat Recovery medium stream 70B of hot-water supply, flows by waste heat recovery heat exchanger 70, can generate hot water effectively.

In addition, owing to second cold-producing medium that constitutes before gas cooler 46 comes out to enter Intermediate Heat Exchanger 80 flows the structure that flows waste heat recovery heat exchanger 70, therefore generate under the utilization situation how of side (hot-water supply side) at hot water, can reduce the refrigerant temperature of second cold-producing medium stream that flows to Intermediate Heat Exchanger 80, therefore can reduce the refrigerant amount of first cold-producing medium stream that flows to Intermediate Heat Exchanger 80.Thus, can increase the refrigerant amount that flows in second cold-producing medium stream, can increase the evaporation capacity of the cold-producing medium among evaporimeter 63A, the 63B, thereby improve the effect of kind of refrigeration cycle.

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

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

Thus, use amount in hot-water supply is many, can't make under the situation that the cold-producing medium that flows in the Waste Heat Recovery medium stream 70B (evaporimeter) of heat pump unit fully evaporates, 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 the directly refrigerant flow path 70A by waste heat recovery heat exchanger 70 of high temperature refrigerant.Thus, can effectively utilize used heat and carry out the temperature-compensating of hot-water supply side.

(D) the gas cooler control of air blast

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

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

In the high-pressure side of refrigerant loop as present embodiment 1 becomes refrigerating plant R more than the supercritical pressure, externally under the situation of gas temperature TA in a certain temperature, below for example+30 ℃, carry out saturated circulation, be higher than+30 ℃ situation under, carry out gas circulation.Therefore when 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, by extraneous gas temperature sensor 56 detected extraneous gas temperature T A under the situation below the lower limit temperature (for example 0 ℃), target high pressure THP the regulation lower limit THPL fix.In addition, externally gas temperature TA is under situation about being higher than more than 30 ℃ the set point of temperature (ceiling temperature), and target high pressure THP fixes at set upper limit value THPH.And externally gas temperature TA is higher than lower limit temperature and is lower than under the situation of ceiling temperature, finds the solution target high pressure THP as described below.

The fiducial temperature that extraneous gas temperature T A more is lower than regulation for example+30 ℃, more determine this desired value THP towards the direction of the desired value THP that reduces high side pressure, extraneous gas temperature T A more is higher than the fiducial temperature of regulation, more determines this desired value THP towards the direction that improves desired value THP.In addition, as mentioned above, the evaporating temperature TE of cold-producing medium more is higher than the fiducial temperature of regulation among evaporimeter 63A, the 63B that obtains according to these low-pressure sensor 32 detected conversion pressures, more determine this desired value THP towards the direction of the desired value THP that improves high side pressure, evaporating temperature TE more is lower than the fiducial temperature of regulation, more determines this desired value THP towards the direction that reduces desired value THP.The figure of the trend of Fig. 3 target high pressure THP that to be expression determined by extraneous gas temperature T A and evaporating temperature TE.

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

And control device C is according to 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, based on the P (ratio of 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 that the gas cooler of deriving as operational ton is with the rotating speed of air blast 47.For this rotating speed, target high pressure THP is more high, and the rotating speed of air blast 47 is more high, and target high pressure THP is more low, and the rotating speed of air blast 47 is more low.

Thus, control device C is according to evaporating temperature (32 detected low pressures conversions obtain according to low-pressure sensor) the TE control gas cooler rotating speed of air blast 47 of cold-producing medium in extraneous gas temperature T A and the evaporimeter, thus, become among the refrigerating plant R of supercritical pressure in the 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 to be varied to according to extraneous gas temperature T A the state of the cold-producing medium of saturated circulation and gas circulation thus, 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 more low, more reduce desired value THP, evaporating temperature TE is more high, more determines this desired value THP on the direction that improves 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, in the high pressure ejection pipe arrangement 42 of the senior side ejiction opening 28 of aforesaid connection compressor 11 and gas cooler 46, be provided with separator 44.The oil that this separator 44 is used for containing from the ejection cold-producing medium of the high pressure of compressor 11 ejections separates with cold-producing medium and catches, and is connected with the oil return loop 73 that makes the oil that captures return compressor 11 at this separator 44.In this oil return loop 73, be provided with the oil cooler 74 that cools off the oil that captures, downstream at this oil cooler 74, oil return loop 73 is branched off into two systems, is connected with the closed container 12 of compressor 11 via filter 75 and flow rate regulating valve (motor-driven valve) 76 respectively.As mentioned above, owing to press in the middle of being retained as in the closed container 12 of compressor 11, therefore 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 that captures oil eliminator 44 in and the closed container 12.In addition, be provided with oil surface sensor 77 for detection of the pasta that is kept at the oil in this closed container 12 at the closed container 12 of compressor 11.

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

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

Thus, at the second rotation compressing member 20,20 interflow, downstream, be pulled to refrigerator unit 3,3 from the high-temperature high-pressure refrigerant of each compressor 11,28 ejections of 11 senior side ejiction opening via separator 44, gas cooler 46 etc.Flowing into the oil that contains in the high-temperature high-pressure refrigerant in the separator 44 separates with cold-producing medium in separator 44 and is captured.And, because the closed container 12 of compressor 11 presses in the middle of being retained as, therefore return compressor 11 via oil return loop 28 under the effect of the pressure reduction of the middle pressure in the high pressure of the oil that captures oil eliminator 44 in and the closed container 12.

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

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

Thus, cause that oil temperature also reduces when causing oil viscosity to rise this situation, can make the oil in the separator 44 return 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 compressor 11.

Especially in the present embodiment, because oil cooler 74 and gas cooler 46 are arranged in the same wind path 45, and irrespectively carry out the control of air blast 47 as described above with the temperature of oil cooler 74, thereby dissolve in the oil easily 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 the separator 44 successfully return compressor 11 without oil cooler 74 via oil bypass loop 78.Therefore, especially under the situation that can't adjust the air cooling amount, can simplify control and the acquisition effect.

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

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

In addition, as present embodiment, having used under the situation of carbon dioxide as cold-producing medium, by controlling as described above, can make oil successfully return compressor 11, and improve refrigerating capacity effectively, can realize the raising of performance.

(F) startability of compressor improves (bypass circulation)

Next, the startability improvement control to compressor 11 describes.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 that are 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.In this bypass circulation 84, be provided with magnetic valve (valve gear) 85.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 control action describe.As mentioned above, under the state of compressor 11 running, in the middle of being boosted to by this first rotation compressing member 18, the refrigerant gas of low pressure that is drawn into the low voltage section of the first rotation compressing member 18 by rudimentary side draught entrance 22 presses and ejection in the closed container 12.The refrigerant gas of pressure to 36 ejections of centre pressure ejection pipe arrangement, is inhaled into senior side draught entrance 26 via the middle pressure suction line 40 that connects intercooler 38 from the rudimentary side ejiction opening 24 of compressor 11 in the middle of in the closed container 12.Be set to the middle nip territory from the zone that is inhaled into by first rotation compressing member 18 ejection and via senior side draught entrance 26 till the second rotation compressing member 20.

The refrigerant gas of middle pressure that is drawn into the middle splenium of the second rotation compressing member 20 by senior side draught entrance 26 is carried out the refrigerant gas that partial compression becomes HTHP by this second rotation compressing member 20, and the zone that is ejected to high pressure ejection pipe arrangement 42 by senior side ejiction opening 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 the high-pressure side.

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

Stop the back and again during starting compressor 11 in the running of above-mentioned 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 have the operating frequency of the torque control of actual effect, as an example, is made as 35Hz in the present embodiment.

Thus, compressor 11 from halted state starting and before rising to the operating frequency of this regulation during, by opening magnetic valve 85, utilize the first rotation compressing member 18 to press, press from rudimentary side ejiction opening 24 to the centre 36 ejections of ejection pipe arrangement in the middle of boosting to and flow into via the low-pressure side zone of bypass circulation 84 to refrigerant loop 1 through the cold-producing medium in the middle nip territory behind the intercooler 38.Thus, the middle nip territory of refrigerant loop 1 and the pressure in low-pressure side zone are all pressed.

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

Therefore, during torque deficiency that the start-up period of compressor 11 produces, can avoid in advance approaching the poor starting that causes because of the pressure of the pressure in middle nip territory and high-pressure area, can realize stablizing and high efficiency running.In addition, control device C closes the stream of magnetic valve 85 and inaccessible bypass circulation 84 after the operating frequency of detected compressor 11 rises to the operating frequency of regulation, carry out aforesaid common kind of refrigeration cycle thus.

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

High pressure ejection pipe arrangement 42 at each compressor 11 of 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 vertical view of Fig. 5, cold-producing medium adjuster 91 is described.This cold-producing medium adjuster 91 is made of the closed container 92 with specified volume, side at this container 92, connection is formed with the cold-producing medium inflow portion 96 that flows into from the cold-producing medium of senior side ejiction opening 28 ejections of compressor 11, and is connected with high pressure ejection pipe arrangement 42 (senior side ejiction opening 28 sides).In addition, in the upper surface of container 92, be communicated with the cold-producing medium outflow portion 97 that is formed with the cold-producing medium outflow that makes in the 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 portion 96, and cold-producing medium delivery chamber 95 and cold-producing medium outflow portion 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, and this suction inlet 98 is connected to form with the suction path 99 that is formed on the 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 90 that is made of leaf valve.This check-valves 90 with flow into from cold-producing medium chamber 94 sides towards the direction of cold-producing medium delivery chamber 95 be forward (with from the senior side ejiction opening 28 of compressor 11 towards the direction of 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 that is 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 loop 73, is communicated with thus with in the container 92.

According to above structure, flow in the chamber 94 to cold-producing medium from the cold-producing medium inflow portion 96 of cold-producing medium adjuster 91 via high temperature ejection pipe arrangement 42 from the cold-producing medium of senior side ejiction opening 28 ejection of compressor 11 and to flow into.Here, because cold-producing medium flows into the volume that chamber 94 has regulation, therefore can absorb pulsation by the noise elimination effect and realize equalization.

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

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

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

That is, under the situation that this check-valves 90 is not set, in the compressor 11 that stops, 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 the oil, therefore can all not press easily.But, when starting compressor 11, because the pressure differential in the refrigerant loop 1 is big, therefore, till refrigerant loop 1 integral body is all pressed, needs the stipulated time, thereby cause the startability variation.

Yet, in the present embodiment, stop compressor 11 after, keep the on high-tension side pressure of refrigerant loop 1 by check-valves 90, can improve the startability of described compressor 11 thus.In addition, because whole inequality is pressed in the refrigerant loop 1, therefore can realize the high efficiency of refrigerating circulatory device.

In addition, as present embodiment, be provided with many, be two compressors 11,11 in this case at refrigerating plant R, under two compressors 11,11 situations about connecting side by side mutually, the cold-producing medium adjuster 91 and the compressor 11,11 separately that possess above-mentioned check-valves 90 are arranged on each compressor 11,11 high pressure ejection pipe arrangement 42, the position before 42 interflow 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 corresponding respectively compressor 11,11 via the oil return pipe 86 of being located at this bottom.

(H) defrosting of evaporimeter control

As mentioned above, each showcase unit 5A, 5B are connected side by side with refrigerant piping 7 and 9 respectively.Be connected with filter 61A, 61B, main throttle mechanism 62A, 62B, evaporimeter 63A, 63B respectively 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, the outlet side that is connected with the evaporimeter 63A that is communicated with this side at the outlet side of a side evaporimeter 63A and the first communicating pipe 64A corresponding to the entrance side of the main throttle mechanism 62B of the opposing party's evaporimeter 63B are provided with magnetic valve (valve gear) 65A at this first communicating pipe 64A.In addition, the outlet side that is connected with the evaporimeter 63B that is communicated with this opposing party at the outlet side of the opposing party's evaporimeter 63B and the second communicating pipe 64B corresponding to the entrance side of the main throttle mechanism 62A of a described side's evaporimeter 63A are provided with magnetic valve (valve gear) 65B in this second communicating pipe 64B.In addition, in the present embodiment, main throttle mechanism 62A, 62B are made of electric expansion valve, but in addition, also can be by capillary, make the bypass pipe of this capillary bypass, magnetic valve constitute throttle mechanism.

In addition, be provided with magnetic valve (valve gear) 66A and 66B in the downstream with the current divider of each communicating pipe 64A, 64B shunting, described each communicating pipe 64A, 64B are connected with each cabinet side refrigerant piping 60A, evaporimeter 63A of 60B or the outlet side of 63B.Constitute 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 that makes gas cooler 46 bypass that constitute refrigerant loop 1.In this gas cooler bypass circulation 71, be provided with magnetic valve 72.And, each magnetic valve 65A, 65B, 66A, 66B, 72 and main throttle mechanism 62A, 62B opened and closed by above-mentioned control device C control.

According to above structure, at first, the defrosting control of a side evaporimeter 63A is described.When carrying out a side the defrosting of evaporimeter 63A, control device C controls above-mentioned stream controlling organization, makes the cold-producing medium that comes out from evaporimeter 63A flow to the first communicating pipe 64A, and the cold-producing medium that comes out from evaporimeter 63B returns 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, being constituted under the situation of 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 in a side evaporimeter 63A, flow into the form of gas refrigerant through the main throttle mechanism 62A that forms standard-sized sheet.Owing to close magnetic valve 66A in advance and open magnetic valve 65A, therefore the cold-producing medium (being gas refrigerant when carrying out gas circulation) that is liquefied of the defrosting by this evaporimeter 63A is through the first communicating pipe 64A, and flows into to the entrance side of the main throttle mechanism 62B corresponding with the opposing party's evaporimeter 63B.

Therefore, the cold-producing medium that is liquefied because of the defrosting of a side evaporimeter 63A is by the main throttle mechanism 62B puffing corresponding with the opposing party's evaporimeter 63B, and evaporates 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 compressor 11.

When the defrosting of the evaporimeter 63B that carries out the opposing party, the above-mentioned stream controlling organization of the following control of control device C makes from second communicating pipe of the refrigerant flow direction 64B that evaporimeter 63B comes out, and the cold-producing medium that comes out from evaporimeter 63A returns compressor 11.That is, main throttle mechanism 62B standard-sized sheet that will be corresponding with this evaporimeter 63B is opened 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 in the opposing party's evaporimeter 63B, flow into the form of gas refrigerant through the main throttle mechanism 62B that forms standard-sized sheet.Owing to close magnetic valve 66B and open magnetic valve 65B, therefore the cold-producing medium (being gas refrigerant when carrying out gas circulation) that is liquefied because of the defrosting of this evaporimeter 63B flows into through the entrance side of the main throttle mechanism 62A of the evaporimeter 63A correspondence of the second communicating pipe 64B Xiang Yuyi side.Therefore, the cold-producing medium that is liquefied because of the defrosting of the opposing party's evaporimeter 63B is by the main throttle mechanism 62A puffing corresponding with a side evaporimeter 63A, and evaporates 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 that liquefies because of defrosting mutually, can eliminate the unfavorable condition of directly returning compressor 11 because of the cold-producing medium of defrosting after liquefying.In addition, can realize the defrosting of above-mentioned evaporimeter 63A, 63B with simple structure.

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

In addition, in the present embodiment, control device C opens the magnetic valve 72 of being located at gas cooler bypass circulation 71 when this defrosting under the situation of low temperature that by extraneous gas temperature sensor 56 detected temperature is regulation.Thus, the high cold-producing medium of the temperature of having avoided gas cooler 46 (having passed through gas cooler bypass circulation 71) that becomes overcritical circulation is flowed into to the evaporimeter that defrosts.

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

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

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

Claims (7)

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

Separator, it separates the oil from the cold-producing medium of described compressing mechanism ejection;

The oil return loop, it makes the oil in this separator turn back to described compressing mechanism;

Oil cooler, it is arranged in this oil return loop;

The oil bypass loop, it makes this oil cooler bypass;

Valve gear, it is arranged in this oil bypass loop;

Current divider (82), it will be divided into first cold-producing medium stream and second cold-producing medium stream from the cold-producing medium that come out described gas cooler (46), make the described first cold-producing medium stream flow to the subsidiary loop of described refrigerating plant, make the described second cold-producing medium stream flow to the major loop of described refrigerating plant;

Auxiliary throttle mechanism (83), it reduces pressure to the first cold-producing medium stream that is flowed in described subsidiary loop by described current divider (82) shunting;

Intermediate Heat Exchanger (80), it carries out by the stream of first cold-producing medium in the post-decompression subsidiary loop of described auxiliary throttle mechanism (83) and the heat exchange of being flowed by second cold-producing medium after described current divider (82) shunting;

Controlling organization, it controls this valve gear so that the oil in the described separator turns back to described compressing mechanism without described oil cooler.

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

Described gas cooler and oil cooler are arranged in the same wind path, by the air blast air cooling.

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

Described controlling organization utilizes described valve gear to open the stream in described oil bypass loop when externally gas temperature is lower than setting.

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

Described controlling organization utilizes described valve gear to open the stream in described oil bypass loop when the temperature of described separator is lower than setting.

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

Use carbon dioxide as described cold-producing medium.

6. refrigerating plant according to claim 3 is characterized in that,

Use carbon dioxide as described cold-producing medium.

7. refrigerating plant according to claim 4 is characterized in that,

Use carbon dioxide as described cold-producing medium.

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