CN104755858A

CN104755858A - Refrigeration device

Info

Publication number: CN104755858A
Application number: CN201380056962.2A
Authority: CN
Inventors: 仓田裕辅; 木屋豊明; 八藤后裕志; 三原一彦; 加藤光洋
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2012-10-31
Filing date: 2013-10-30
Publication date: 2015-07-01
Also published as: JPWO2014068967A1; WO2014068967A1; JP6292480B2

Abstract

Provided is a refrigeration device which can, independently of outside air temperature, ensure stable refrigeration performance when the high-pressure side has a supercritical pressure, and which can improve cost and the easiness of construction. A refrigeration device is provided with: a pressure regulating throttle means which is connected to a refrigerant circuit which is located downstream of a gas cooler and upstream of a main throttle means; a decompression tank which is connected to a refrigerant circuit which is located downstream of the pressure regulating throttle means and upstream of the main throttle means; a split heat exchanger which is provided in a refrigerant circuit which is located downstream of the decompression tank and upstream of the main throttle means; an auxiliary circuit which allows a refrigerant within the decompression tank to be sucked into the intermediate pressure section of a compressor after causing the refrigerant to flow to a first flow passage in the split heat exchanger through an auxiliary throttle means; and a main circuit which allows a refrigerant to flow out from the lower part of the decompression tank, causes the refrigerant to flow to a second flow passage in the split heat exchanger, subjects the refrigerant to heat exchange with a refrigerant flowing through the first flow passage, and then causes the refrigerant, having been subjected to heat exchange with the refrigerant flowing through the first flow passage, to flow into the main throttle means.

Description

Refrigerating plant

Technical field

The present invention relates to and form refrigerant loop by compression set, gas cooler, main throttling arrangement and evaporimeter, high-pressure side is the refrigerating plant of supercritical pressure.

Background technology

In the past, this refrigerating plant forms kind of refrigeration cycle by compression set, gas cooler, throttling arrangement etc., the cold-producing medium compressed by compression set is dispelled the heat by gas cooler, after being reduced pressure by throttling arrangement, by evaporimeter, cold-producing medium is evaporated, by the evaporation of cold-producing medium now, ambient air is cooled.In recent years, in this refrigerating plant, freon series coolant can not be used because of natural environmental stress etc.Therefore, as the substitute of freon refrigerant, develop the formation using natural refrigerant and carbon dioxide.This carbon dioxide coolant is it is known that the excessive cold-producing medium of height pressure reduction, and critical pressure is low, makes the high-pressure side of refrigerant circulation become supercriticality (for example, referring to patent document 1) by compression.

In addition, in the heat pump assembly forming water heater, also developed the carbon dioxide coolant using and can be obtained good heat effect by gas cooler, the cold-producing medium double expansion flowed out from gas cooler is made in this situation, between each expansion gear, gas-liquid separator is set, gas inject (for example, referring to patent document 2) can be carried out to compressor.

On the other hand, in the evaporimeter being arranged at such as showcase etc., utilize heat-absorbing action by the refrigerating plant that cools in cabinet, there is following problem, that is, because of the reason that ambient atmos temperature (heat source temperature of gas cooler side) is high, under the condition that the refrigerant temperature of gas cooler outlet uprises, the specific enthalpy of evaporator inlet increases, so refrigerating capacity significantly reduces.Now, in order to ensure refrigerating capacity, when making the ejection pressure (high side pressure) of compression set rise, compression power increases, and the coefficient of performance can reduce.

Therefore, the refrigerating plant having so-called separate type to circulate is proposed: the refrigerant branches cooled by gas cooler is become two flow of refrigerant, by auxiliary throttling arrangement by by after the flow of refrigerant throttling of shunting, it is made to flow to the path of a side of separate heat exchanger, make another stream of another refrigerant flow direction separate heat exchanger and after having carried out heat exchange, make it flow into evaporimeter via main throttling arrangement.According to this refrigerating plant, by the first flow of refrigerant after puffing, second refrigerant stream can be cooled, and by reducing the specific enthalpy of evaporator inlet, refrigerating capacity (for example, referring to patent document 3) can be improved.

Patent document 1:(Japan) JP 7-18602 publication

Patent document 2:(Japan) JP 2007-178042 publication

Patent document 3:(Japan) JP 2011-133207 publication

But, when the refrigerated condition of the refrigerator that the evaporating temperature of the cold-producing medium particularly in evaporimeter uprises etc., if the change of ambient atmos temperature, then the pressure flowing into the cold-producing medium of main throttling arrangement significantly changes, and the control of main throttling arrangement and refrigerating capacity become unstable.In addition, in shops such as supermarkets, from the showcase the supply system cryogen of the refrigeration machine being provided with compression set and gas cooler in the shop being provided with main throttling arrangement and evaporimeter, until the high side pressure of the main throttling arrangement of showcase side is high, therefore, withstand voltage high pipe arrangement must be used as long refrigerant piping (liquid line), be constructed into person's character not good.

In addition, when starting running under the environment that extraneous gas temperature is high, in the refrigerant loop of the high refrigerated condition of evaporating temperature, first flow of refrigerant does not liquefy, even if form separate type as described above circulation, the cooling effect of the second refrigerant stream based on the first flow of refrigerant also almost can not be expected.Therefore, can not to main throttling arrangement conveying liquid cryogen.In addition, when using the such cold-producing medium of carbon dioxide, also having because of reason and make high side pressure significantly change in season, being difficult to the problem differentiating suitable refrigerant charge amount.

Summary of the invention

The present invention sets up to solve this existing technical task, its object is to provide a kind of when high-pressure side is supercritical pressure, not by ambient atmos temperature, stable refrigerating capacity can be guaranteed, the refrigerating plant of application property and cost can also be improved.

The refrigerating plant of first aspect present invention, refrigerant loop is formed by compression set, gas cooler, main throttling arrangement, evaporimeter, high-pressure side is supercritical pressure, wherein, possess: pressure adjustment throttling arrangement, it is connected with the refrigerant loop of the downstream of gas cooler and the upstream side of main throttling arrangement; Decompression tank, itself and pressure regulate and are connected with the refrigerant loop of the downstream of throttling arrangement and the upstream side of main throttling arrangement; Separate heat exchanger, it is located in the refrigerant loop of the decompression downstream of tank and the upstream side of main throttling arrangement; Subsidiary loop, cold-producing medium is drawn into the middle splenium of compression set to flow to the first flow path of separate heat exchanger via auxiliary throttling arrangement after by its cold-producing medium in decompression tank; Major loop, it flows out from decompression tank bottom making cold-producing medium, flows to the second flow path of separate heat exchanger and after having carried out heat exchange with the cold-producing medium flowed in first flow path, makes flow of refrigerant become owner of throttling arrangement.

The refrigerating plant of second aspect present invention, on basis in above-mentioned, possess the control device of controlled pressure adjustment throttling arrangement, the pressure of the cold-producing medium flowing into main throttling arrangement, by the aperture of controlled pressure adjustment throttling arrangement, is adjusted to the setting of regulation by control device.

The refrigerating plant of third aspect present invention, on basis in above-mentioned, control device, when the high side pressure of the refrigerant loop of specific pressure adjustment throttling arrangement upstream side rises to set upper limit value, makes the aperture of pressure adjustment throttling arrangement increase.

The refrigerating plant of fourth aspect present invention, on the basis of above-mentioned each side, the subsidiary loop of the upstream side of auxiliary throttling arrangement is by making cold-producing medium flow out from decompression tank top and flowing into the gas pipe arrangement of auxiliary throttling arrangement and make cold-producing medium flow out from decompression tank bottom and assist the liquid pipe arrangement of throttling arrangement to form via valve gear inflow.

The refrigerating plant of fifth aspect present invention, on basis in above-mentioned, control device based on the norm controlling valve gear representing ambient atmos temperature, when extraneous gas temperature rises, shut-off valve assembly, situation about reducing at extraneous gas temperature opens valve gear.

The refrigerating plant of sixth aspect present invention, on the basis in above-mentioned, control device is based on the norm controlling valve gear of the evaporating temperature of the cold-producing medium represented in evaporimeter, and evaporating temperature is higher, with lower ambient atmos temperature shut-off valve assembly.

The refrigerating plant of seventh aspect present invention, on the basis of above-mentioned each side, is provided with the inner heat exchanger making the cold-producing medium of the main throttling arrangement of inflow and carry out heat exchange from the cold-producing medium that evaporimeter flows out.

The refrigerating plant of eighth aspect present invention, on basis in above-mentioned, inner heat exchanger possesses the second stream of the first flow path of the flow of refrigerant flowing into main throttling arrangement and the flow of refrigerant from evaporimeter outflow, make the cold-producing medium that flows in the first flow path of inner heat exchanger and carry out heat exchange at the cold-producing medium of the second flow path of inner heat exchanger, further, the bypass circulation be connected in parallel with the second stream of the first flow path of inner heat exchanger or inner heat exchanger and the bypass valve gear being located at this bypass circulation is possessed.

The refrigerating plant of ninth aspect present invention, on basis in above-mentioned, possesses the control device controlling bypass valve gear, this control device is based on the temperature of the cold-producing medium of first flow path and the cold-producing medium from the second stream outflow of inner heat exchanger that flow into inner heat exchanger, when the temperature of the cold-producing medium flowed out from the second stream of inner heat exchanger is higher than the temperature of the cold-producing medium of the first flow path of inflow inner heat exchanger, open bypass valve gear.

The refrigerating plant of tenth aspect present invention, on the basis of above-mentioned each side, as cold-producing medium, uses carbon dioxide.

According to the present invention, refrigerant loop is being formed by compression set, gas cooler, main throttling arrangement, evaporimeter, high-pressure side is in the refrigerating plant of supercritical pressure, possess: pressure adjustment throttling arrangement, it is connected with the refrigerant loop of the downstream of gas cooler and the upstream side of main throttling arrangement; Decompression tank, itself and this pressure regulate and are connected with the refrigerant loop of the downstream of throttling arrangement and the upstream side of main throttling arrangement; Separate heat exchanger, it is located at the refrigerant loop of the decompression downstream of tank and the upstream side of main throttling arrangement; Subsidiary loop, it is making after the cold-producing medium in decompression tank flows to the first flow path of separate heat exchanger via auxiliary throttling arrangement, to be drawn into the middle splenium of compression set; Major loop, it makes cold-producing medium from the outflow of decompression tank bottom, flow to separate heat exchanger the second stream and after having carried out heat exchange with the cold-producing medium flowed in first flow path, it is made to flow into main throttling arrangement, therefore, by auxiliary throttling arrangement, the cold-producing medium of the first flow path flowing at the separate heat exchanger forming subsidiary loop is expanded, by the refrigerant cools of the second flow path of the separate heat exchanger at formation major loop, can reduce the specific enthalpy of evaporator inlet and effectively improve refrigerating capacity.

In addition, the cold-producing medium flowed in the first flow path of separate heat exchanger turns back to the middle splenium of compression set, and therefore, the refrigerant amount being inhaled into the low voltage section of compression set reduces, and the work done during compression amount for the compression set being compressed to middle pressure from low pressure reduces.Consequently, the compression power of compression set reduces, and the coefficient of performance improves.

Particularly, by pressure adjustment throttling arrangement, the cold-producing medium flowed out from gas cooler expanded and make it flow in decompression tank, therefore, the pressure of the cold-producing medium flowing into main throttling arrangement is reduced by this pressure adjustment throttling arrangement, thus as the pipe arrangement reaching main throttling arrangement, the pipe arrangement that compressive resistance is low can be used.In addition, also there is the effect of variation by the circularly cooling dosage in decompression tank absorption refrigeration agent loop, so the error of also absorption refrigeration agent charging quantity.Thus, the improvement of application property and construction cost can also be realized.

In addition, by being expanded by pressure adjustment throttling arrangement, a part for the cold-producing medium of liquefaction becomes evaporation in decompression tank and the gas refrigerant that temperature reduces, and remaining is liquid refrigerant, is stored in bottom in decompression tank for the time being.And, in this decompression tank, the liquid refrigerant of bottom flows into main throttling arrangement via the second stream of separate heat exchanger forming major loop, so can flow of refrigerant be made to become owner of throttling arrangement under full liquid status, the raising of the refrigerating capacity of the high refrigerated condition of the evaporating temperature of evaporimeter particularly can be realized.

Particularly utilize the aperture as the control device controlled pressure adjustment throttling arrangement of second aspect present invention, the pressure of the cold-producing medium flowing into main throttling arrangement is adjusted to the setting of regulation, the change of the ambient atmos temperature of the transition along with season can be prevented and the pressure flowing into the cold-producing medium of main throttling arrangement significantly changes, usually can maintain identical set value.Thus, particularly under the refrigerated condition that the evaporating temperature of evaporimeter is high, the control stabilisation of main throttling arrangement can be made, and stably guarantee refrigerating capacity.

In this situation, by arranging pressure adjustment throttling arrangement, the danger that the high side pressure with the refrigerant loop of its upstream side increases, but as third aspect present invention, control device is when the high side pressure of the refrigerant loop of specific pressure adjustment throttling arrangement upstream side rises to set upper limit value, the aperture of pressure adjustment throttling arrangement is increased, and the exception can eliminating high side pressure thus rises.Thereby, it is possible to the stopping (protection act) of the compression set avoiding abnormal pressure to cause in advance.

In addition, according to a fourth aspect of the present invention, on the basis of above-mentioned each side, flows out by making cold-producing medium from decompression tank top and flow into and assist the gas pipe arrangement of throttling arrangement, to flow out from decompression tank bottom with making cold-producing medium and the liquid pipe arrangement flowing into auxiliary throttling arrangement via valve gear forms the subsidiary loop of the upstream side of auxiliary throttling arrangement, therefore, expanded by pressure adjustment throttling arrangement and liquefy, enter in decompression tank, a part is evaporated and the gas refrigerant that temperature is reduced and remaining liquid refrigerant optionally flow to the first flow path of separate heat exchanger by gas pipe arrangement and liquid pipe arrangement.

Namely, such as under the environment that extraneous gas temperature is high, the high side pressure of refrigerant loop also increases, so be reduced to set value as escribed above in order to the pressure of the cold-producing medium making the main throttling arrangement of inflow, control device controls in the mode of the aperture reducing pressure adjustment throttling arrangement.In this condition, the liquid refrigerant be stored in decompression tank tails off, and when it flows to the first flow path flowing of separate heat exchanger, is difficult to guarantee through the liquid refrigerant of the second stream towards main throttling arrangement.

In addition, reduce at extraneous gas temperature, become the euthermic environment of ambient atmos, when high side pressure also declines, control device has the aperture opening tendency ground controlled pressure adjustment throttling arrangement, and the refrigerant amount be stored in decompression tank also increases.And ambient atmos temperature declines further, become the environment that ambient atmos temperature is low, when high side pressure declines further, a large amount of storage of liquids cold-producing medium in decompression tank.

Therefore, by the control device of such as fifth aspect present invention, if based on the norm controlling valve gear representing ambient atmos temperature, the shut-off valve assembly when extraneous gas temperature rises, valve gear is opened when extraneous gas temperature reduces, under the environment that above-mentioned ambient atmos temperature is high, then close the valve gear of liquid-mixing pipe, the gas refrigerant in decompression tank can be made to flow to the first flow path of separate heat exchanger from gas pipe arrangement.Thus, the utilization gas refrigerant that temperature have dropped in decompression tank is by the refrigerant cools of the second flow path at separate heat exchanger, after liquid refrigerant in decompression tank can being cooled in the second stream of separate heat exchanger, it is supplied to main throttling arrangement.In this condition, refrigerant loop becomes so-called compound expansion circulation.

On the other hand, under the euthermic environment of above-mentioned ambient atmos, open the valve gear of liquid pipe arrangement, the gas refrigerant in decompression tank and liquid refrigerant can be made to flow to the first flow path of separate heat exchanger from gas pipe arrangement and liquid pipe arrangement both sides.Thus, the gas refrigerant that temperature have dropped in decompression tank and the liquid refrigerant passing through to assist throttling arrangement to expand can be utilized the refrigerant cools of the second flow path at separate heat exchanger, after liquid refrigerant in decompression tank more strongly can being cooled in the second stream of separate heat exchanger, it is supplied to main throttling arrangement.In this condition, refrigerant loop become above-mentioned compound expansion circulation and so-called separate type circulation and with circulate.

And, under the environment that above-mentioned ambient atmos temperature is low, by opening the valve gear of liquid pipe arrangement, the liquid refrigerant be stored in a large number in decompression tank can be made from liquid pipe arrangement to flow to the first flow path of separate heat exchanger.Thus, the liquid refrigerant expanded by auxiliary throttling arrangement can be utilized more strongly to cool the cold-producing medium of the second flow path at separate heat exchanger, after liquid refrigerant in decompression tank is strongly cooled in the second stream of separate heat exchanger, it can be supplied to main throttling arrangement.In this condition, refrigerant loop becomes the circulation of above-mentioned separate type.

Like this, compound expansion circulation and separate type circulation can be switched, so can the more stable and refrigerating plant that operates efficiently according to ambient atmos temperature environment.

In this situation, as sixth aspect present invention, control device is based on the norm controlling valve gear of the evaporating temperature of the cold-producing medium represented in evaporimeter, this evaporating temperature is higher, with lower ambient atmos temperature shut-off valve assembly, thus, in the running under the state that the evaporating temperatures such as refrigerated condition are high, when ambient atmos temperature raises, above-mentioned compound expansion circulation is switched to step faster, can guarantee, towards the liquid refrigerant of main throttling arrangement, the refrigerating capacity under refrigerated condition can be maintained.

On the other hand, at the cryogenic conditions etc. that evaporating temperature is low, the supercooling flowing into the cold-producing medium of main throttling arrangement at separate heat exchanger is not adopted in above-mentioned compound expansion circulation, but according to a sixth aspect of the present invention, due to as far as possible with separate type cycle operation, so the cold-producing medium supercooling effectively of main throttling arrangement can will be flowed into.Thus, when operating with different evaporating temperatures, also can realize the running efficiency optimization of refrigerating plant.

In addition, as seventh aspect present invention, by arranging the inner heat exchanger making the cold-producing medium of the main throttling arrangement of inflow and carry out heat exchange from the cold-producing medium that evaporimeter flows out, the cold-producing medium of the low temperature flowed out from evaporimeter can be passed through by flowing into the refrigerant cools of main throttling arrangement, so the specific enthalpy of evaporator inlet can be reduced and effectively improve refrigerating capacity at inner heat exchanger.

Particularly under the environment that extraneous gas temperature is high, there is not the pressure differential of the middle splenium being adjusted to pressure in the decompression tank of setting and compression set by pressure adjustment throttling arrangement.In this situation, auxiliary throttling arrangement is roughly full-gear, so according to the difference of situation, almost can not by the cold-producing medium supercooling of the major loop in the second flow path by the cold-producing medium of the subsidiary loop flowed in the first flow path of separate heat exchanger, the cold-producing medium of large quantity of fluid is not carried to main throttling arrangement, but in this condition, also the refrigerant cools of main throttling arrangement will can be flowed at inner heat exchanger by the cold-producing medium of the low temperature flowed out from evaporimeter, with full liquid status to main throttling arrangement the supply system cryogen, so the improvement of refrigerating capacity can be realized.

At this, there is the temperature of the cold-producing medium flowed out from evaporimeter than flowing into the high situation of the cold-producing medium of main throttling arrangement when dropping (プ Le ダウ Application) etc., but as eighth aspect present invention, bypass circulation is flowed into the cold-producing medium of main throttling arrangement with making to flow in the first flow path of inner heat exchanger, with to flow out from evaporimeter and the second stream of the first flow path or inner heat exchanger of carrying out the inner heat exchanger of heat exchange at the cold-producing medium of the second flow path of inner heat exchanger is connected in parallel, bypass valve gear is provided with at this bypass circulation, by the control device of such as ninth aspect present invention, based on the temperature of the cold-producing medium of first flow path and the cold-producing medium from the second stream outflow of inner heat exchanger that flow into inner heat exchanger, when the temperature of the cold-producing medium flowed out from the second stream of inner heat exchanger is higher than the temperature of the cold-producing medium of the first flow path of inflow inner heat exchanger, by opening bypass valve gear, in main throttling arrangement, be flowing in inner heat exchanger do not carry out the cold-producing medium of heat exchange with the cold-producing medium carrying out flash-pot.

Thus, the cold-producing medium can eliminated in advance by flowing out from evaporimeter heats the unfavorable condition of the cold-producing medium flowing into main throttling arrangement conversely.

Particularly, as tenth aspect present invention, as cold-producing medium use have carbon dioxide when, effectively improve refrigerating capacity by above-mentioned each invention, the raising of performance can be realized.

Accompanying drawing explanation

Fig. 1 is the refrigerant loop figure of the refrigerating plant applying one embodiment of the invention;

Fig. 2 is the P-H line chart of 2 grades of expansion cycles that the control device of the refrigerating plant of Fig. 1 performs;

Fig. 3 is 2 grades of expansion cycles of the control device execution of the refrigerating plant of Fig. 1 and the P-H line chart also using circulation of separate type circulation;

Fig. 4 is the P-H line chart of the separate type circulation that the control device of the refrigerating plant of Fig. 1 performs;

Fig. 5 is the figure of the switching action of the circulation of key diagram 2 ~ Fig. 4.

Description of symbols

R: refrigerating plant

1: refrigerant loop

3: refrigeration machine assembly

4: showcase

8,9: refrigerant piping

11: compressor

15: inner heat exchanger

15A: first flow path

15B: the second stream

22: cold-producing medium imports pipe arrangement

26: middle pressure sucks pipe arrangement

28: gas cooler

29: separate heat exchanger

29A: first flow path

29B: the second stream

32: gas cooler outlet pipe arrangement

33: pressure adjustment throttling arrangement

36: decompression tank

37: gas cooler outlet pipe arrangement

38: major loop

39: main throttling arrangement

41: evaporimeter

42: gas pipe arrangement

43: auxiliary throttling arrangement

44: middle pressure returns pipe arrangement

45: bypass circulation

46: liquid pipe arrangement

47: magnetic valve (valve gear)

48: subsidiary loop

50: magnetic valve (bypass valve gear)

57: control device (control device)

Detailed description of the invention

Hereinafter, with reference to the accompanying drawings of embodiments of the present invention.Fig. 1 is the refrigerant loop figure of the refrigerating plant R being suitable for one embodiment of the invention.The refrigerating plant R of the present embodiment possesses refrigeration machine assembly 3, the showcase 4 of one or more (only the representing one in accompanying drawing) be arranged in the sales field in shop of the Machine Room being arranged at the shops such as supermarket etc., these refrigeration machine assemblies 3 and showcase 4 are via module outlet 6 and module inlet 7, connected by refrigerant piping (liquid line) 8 and refrigerant piping 9, form the refrigerant loop 1 of regulation.

The carbon dioxide of on high-tension side refrigerant pressure (high-pressure) for more than its critical pressure (overcritical) uses as cold-producing medium by this refrigerant loop 1.This carbon dioxide coolant is excellent to environment and considers the natural refrigerant of combustibility and toxicity etc.In addition, as the oil of lubricating oil, such as, use the existing oil such as mineral oil (mineral products oil), alkylbenzene oil, ether oil, ester oil, PAG (poly-alkyl diol).

Refrigeration machine assembly 3 possesses the compressor 11 as compression set.In the present embodiment, compressor 11 is bosom pressure 2-stage compression type rotary compressors, has and is accommodated in the electric element 13 as driving element on the top of the inner space of this closed container 12 by closed container 12, configuration and is configured at the downside of this electric element 13 and rotates shaft-driven first (rudimentary side) rotary compression element (first compressing member) 14 and second (senior side) rotary compression element (the second compressing member) 16 rotation/compression mechanism section formed by it.

First rotary compression element 14 of compressor 11 will suck the low pressure refrigerant compression of compressor 11 from the low-pressure side of refrigerant loop 1 via refrigerant piping 9, boost to middle pressure and spray, second rotary compression element 16 and then suction are compressed by the first rotary compression element 14 and the cold-producing medium of the middle pressure sprayed, compress and boost to high pressure, the high-pressure side to refrigerant loop 1 sprays.Compressor 11 is Variable frequency type frequency compressors, by changing the operating frequency of electric element 13, can control the rotating speed of the first rotary compression element 14 and the second rotary compression element 16.

Be formed in the side of the closed container 12 of compressor 11 be communicated with the first rotary compression element 14 rudimentary side suction ports 17, to export 18 with the rudimentary side spray be communicated with in closed container 12, the senior side suction ports 19 that is communicated with the second rotary compression element 16 and senior side spray export 21.Cold-producing medium imports one end of pipe arrangement 22 and is connected with the rudimentary side suction ports 17 of compressor 11, and its other end is connected with refrigerant piping 9 by module inlet 7.The the second stream 15B being provided with inner heat exchanger 15 in pipe arrangement 22 is imported at this cold-producing medium.

The refrigerant gas sucking the low pressure (LP: be about 2.6MPa usually operating condition) of the low voltage section of the first rotary compression element 14 from rudimentary side suction ports 17 boosts to middle pressure (MP: be about 5.5MPa usually under operating condition) by this first rotary compression element 14, sprays in closed container 12.Thus, in closed container 12 be middle pressure (MP).

And one end of middle pressure ejection pipe arrangement 23 exports 18 with the rudimentary side spray of the compressor 11 of the refrigerant gas of pressing in the middle of the ejection in closed container 12 and is connected, and its other end is connected with the entrance of air-breathing cooler 24.This air-breathing cooler 24 is by the equipment of the refrigerant air cooling of the middle pressure sprayed from the first rotary compression element 14, one end that middle pressure sucks pipe arrangement 26 is connected with the outlet of this air-breathing cooler 24, and this centre pressure sucks the other end of pipe arrangement 26 and is connected with the senior side suction ports 19 of compressor 11.

From senior side suction ports 19 be drawn into the second rotary compression element 16 in the middle of the refrigerant gas of pressure (MP) carry out second level compression by this second rotary compression element 16 and become the refrigerant gas of HTHP (HP: be usually the supercritical pressure of about 9MPa operating condition).

And one end of high pressure ejection pipe arrangement 27 exports 21 with the senior side spray of side, hyperbaric chamber of the second rotary compression element 16 being located at compressor 11 and is connected, and its other end is connected with the entrance of gas cooler (radiator) 28.20 is be inserted in the oil eliminator in this high pressure ejection pipe arrangement 27.Oil in the cold-producing medium that sprays from compressor 11 is separated by oil eliminator 20, returns in the closed container 12 of compressor 11 via the oily path 25A of oil cooler 25 and motor-driven valve 25B.In addition, 55 is float switches of the pasta detected in compressor 11.

The ejection refrigerant cools of high pressure that gas cooler 28 will spray from compressor 11, is equipped air cooled for this gas cooler 28 gas cooler pressure fan 31 near gas cooler 28.In the present embodiment, gas cooler 28 and above-mentioned air-breathing cooler 24 are arranged in parallel, and they are disposed in identical wind path.

One end of gas cooler outlet pipe arrangement 32 is connected with the outlet of gas cooler 28, and the other end of this gas cooler outlet pipe arrangement 32 regulates with pressure and is connected with the entrance of throttling arrangement (electric expansion valve) 33.The cold-producing medium throttling of flowing out from gas cooler 28 makes it expand by this pressure adjustment throttling arrangement 33, and its outlet is connected via the top of tank entrance pipe arrangement 34 with decompression tank 36.

This decompression tank 36 is volume that inside has the space of specified volume, and one end of tank outlet pipe arrangement 37 is connected with its underpart, and the other end of this tank outlet pipe arrangement 37 is connected with refrigerant piping 8 by module outlet 6.Be provided with the second stream 29B of separate heat exchanger 29 in this tank outlet pipe arrangement 37, and export at the tank than this separate heat exchanger 29 downstream the first flow path 15A being provided with inner heat exchanger 15 in pipe arrangement 37.This tank outlet pipe arrangement 37 forms major loop 38 of the present invention.In addition, bypass circulation 45 is connected in parallel with the first flow path 15A of inner heat exchanger 15, and the magnetic valve 50 as bypass valve gear is located in this bypass circulation 45.

On the other hand, the showcase 4 be arranged in shop is connected with refrigerant piping 8 and 9.The main throttling arrangement (electric expansion valve) 39 as throttling arrangement and evaporimeter 41 is provided with in showcase 4, be connected successively between refrigerant piping 8 with refrigerant piping 9 (, in refrigerant piping 8 side, evaporimeter 41 is in refrigerant piping 9 side for main throttling arrangement 39).The not shown circulating cold air pressure fan of blowing to this evaporimeter 41 is provided with evaporimeter 41 is adjacent.And, refrigerant piping 9 as described above with import pipe arrangement 22 via cold-producing medium and be connected with the rudimentary side suction ports 17 of the first rotary compression element 14 being communicated with compressor 11.

On the other hand, one end of gas pipe arrangement 42 is connected with the top of decompression tank 36, and the other end of this gas pipe arrangement 42 is connected with the entrance of auxiliary throttling arrangement (electric expansion valve) 43.One end that middle pressure returns pipe arrangement 44 is connected with the outlet of this auxiliary throttling arrangement 43, and its other end, as an example in the territory, middle nip be connected with the middle splenium of compressor 11, presses the midway sucking pipe arrangement 26 to be communicated with centre.In this centre, pressure returns the first flow path 29A being provided with separate heat exchanger 29 in pipe arrangement 44, and is returning in pipe arrangement 44 than pressure in the middle of this separate heat exchanger 29 downstream the second stream 25C being provided with oil cooler 25.

In addition, one end of liquid pipe arrangement 46 is connected with the bottom of decompression tank 36, and the other end of this liquid pipe arrangement 46 is communicated with the midway of gas pipe arrangement 42.In addition, in this liquid pipe arrangement 46, be provided with the magnetic valve 47 as valve gear.In the middle of these, pressure returns pipe arrangement 44, auxiliary throttling arrangement 43, the gas pipe arrangement 42 being in the upstream side of auxiliary throttling arrangement 43 and liquid pipe arrangement 46 form subsidiary loop 48 of the present invention.

By such formation, pressure adjustment throttling arrangement 33 is positioned at the downstream of gas cooler 28 and the upstream side of main throttling arrangement 39.In addition, the tank 36 that reduces pressure is positioned at the downstream of pressure adjustment throttling arrangement 33 and the upstream side of main throttling arrangement 39.In addition, separate heat exchanger 29 is positioned at the decompression downstream of tank 36 and the upstream side of main throttling arrangement 39, as above forms the refrigerant loop 1 of the refrigerating plant R of the present embodiment.

At this refrigerant loop 1, various sensor is installed everywhere.That is, high pressure sensor 49 is installed to detect the high side pressure HP (pressure between the senior side spray outlet 21 of compressor 11 and the entrance of pressure adjustment throttling arrangement 33) of refrigerant loop 1 at high pressure ejection pipe arrangement 27.In addition, import pipe arrangement 22 at cold-producing medium and low pressure sensor 51 is installed to detect the low-pressure lateral pressure LP (pressure between the outlet of main throttling arrangement 39 and rudimentary side suction ports 17) of refrigerant loop 1.In addition, middle pressure sensor 52 is installed to detect the pressure i.e. middle pressure MP (in closed container 12 and between senior side suction ports 19, the pressure returned in pipe arrangement 44 is pressed in outlet, the centre of auxiliary throttling arrangement 43) in the territory, middle nip of refrigerant loop 1 at centre pressure suction pipe arrangement 26.

In addition, the tank outlet pipe arrangement 3 in separate heat exchanger 29 downstream is provided with module outlet sensor 53, and this module outlet sensor 53 detects the pressure TP in decompression tank 36.Pressure in this decompression tank 36 is and flows out from refrigeration machine assembly 3 and to flow into the pressure of the cold-producing medium of main throttling arrangement 39 from refrigerant piping 8.In addition, at the tank outlet pipe arrangement 37 of inner heat exchanger 15 upstream side, module outlet temperature sensor 54 is installed, detects the temperature IT of the cold-producing medium of the first flow path 15A flowing into inner heat exchanger 15.In addition, the cold-producing medium in inner heat exchanger 15 downstream imports on pipe arrangement 22 and is provided with module inlet temperature sensor 56, detects the temperature OT of the cold-producing medium flowed out from the second stream 15B of inner heat exchanger 15.

And the input of the control device 57 of the control device of the refrigeration machine assembly 3 that these sensors 49,51,52,53,54,56 are made up of microcomputer with formation is connected, and float switch 55 is also connected with the input of control device 57.In addition, the electric element 13 of compressor 11, motor-driven valve 25B, gas cooler pressure fan 31, pressure adjustment throttling arrangement 33, auxiliary throttling arrangement 43, magnetic valve 47, magnetic valve 50, main throttling arrangement 39 are connected with the output of control device 57, and control device 57 controls based on the output of each sensor and setting data etc.

In addition, the equipment that main throttling arrangement 39 and the above-mentioned circulating cold air pressure fan of showcase 4 side also control as control device 57 is described later, but it, in fact via the main control unit (not shown) in shop, is controlled by the control device (not shown) of showcase 4 side with control device 57 teamwork.Therefore, control device of the present invention is the concept comprising the control device of control device 57 and showcase 4 side, above-mentioned main control unit etc.

By above formation, the action of refrigerating plant R is then described with reference to Fig. 2 ~ Fig. 5.If driven the electric element 13 of compressor 11 by control device 57, then the first rotary compression element 14 and the second rotary compression element 16 rotate, the refrigerant gas leaning on the low voltage section of the first rotary compression element 14 to suck low pressure (above-mentioned LP: be about 2.6MPa under operating condition usually) than rudimentary side suction ports 17.And, boost to middle pressure (above-mentioned MP: be about 5.5MPa usually under operating condition) by the first rotary compression element 14 and spray in closed container 12.Thus, middle pressure (MP) is become in closed container 12.

And in the middle of in closed container 12, the refrigerant gas of pressure enters air-breathing cooler 24 from rudimentary side spray outlet 18 via centre pressure ejection pipe arrangement 23, after this is by Air flow, sucks pipe arrangement 26 return senior side suction ports 19 through centre pressure.The refrigerant gas turning back to the middle pressure (MP) of this senior side suction ports 19 is inhaled into the second rotary compression element 16, second level compression is carried out by this second rotary compression element 16, become the refrigerant gas of HTHP (HP: be the supercritical pressure of about 9MPa under above-mentioned usual operating condition), spray to high pressure ejection pipe arrangement 27 from senior side spray outlet 21.

The refrigerant gas sprayed to high pressure ejection pipe arrangement 27 flows into oil eliminator 20, the oil comprised is separated in cold-producing medium.Separated oil in the oily path 25A of oil cooler 25, as aftermentioned by pressure in the middle of flowing in the second stream 25C return pipe arrangement 44 in the middle of pressure refrigerant cools after, return in closed container 12 via motor-driven valve 25B.In addition, the pasta in the closed container 12 that control device 57 detects based on float switch 55 controls motor-driven valve 25B, regulates the back amount of oil, maintains the pasta in closed container 12.

(1) control of pressure adjustment throttling arrangement and auxiliary throttling arrangement

On the other hand, the refrigerant gas having carried out oily separation by oil eliminator 20 then inflow gas cooler 28 and by after Air flow, arrive pressure adjustment throttling arrangement 33 through gas cooler outlet pipe arrangement 32.This pressure adjustment throttling arrangement 33 is arranged in order to the pressure (flowing into the pressure of the cold-producing medium of main throttling arrangement 39) in decompression tank 36 is adjusted to setting (certain value) SP of regulation, based on the output of module outlet sensor 53, control its valve opening by control device 57.This setting SP is set in lower than common high side pressure HP and higher than middle pressure MP such as 6MPa.And, the pressure of control device 57 in the decompression tank 36 that module outlet sensor 53 detects (flowing into the pressure of the cold-producing medium of main throttling arrangement 39) rises from setting SP, the valve opening of pressure adjustment throttling arrangement 33 is reduced and throttling, on the contrary, when declining from setting SP, make valve opening increase and to the direction controlling opened.

Pass through to be liquefied by this pressure adjustment throttling arrangement 33 throttling expansion from the refrigerant gas of the supercriticality of gas cooler 28 outflow, flow in decompression tank 36 from top through tank entrance pipe arrangement 34, a part is evaporated.This decompression tank 36 plays the effect of the variation of the cold-producing medium the effect be isolated that store the liquid/gas flowed out from pressure adjustment throttling arrangement 33 for the time being and the pressure absorbing high side pressure change and circulating mass of refrigerant.The liquid refrigerant lodging in bottom in this decompression tank 36 flows out (major loop 38) from tank outlet pipe arrangement 37, separate heat exchanger 29 the second stream 29B as aftermentioned by the refrigerant cools (supercooling) flowed at first flow path 29A (subsidiary loop 48) after, and then at the first flow path 15A of inner heat exchanger 15, by the refrigerant cools flowed at the second stream 15B, afterwards, flow out from refrigeration machine assembly 3, flow into main throttling arrangement 39 from refrigerant piping 8.In addition, hereinafter the action of magnetic valve 50 is described.

Flowing into the cold-producing medium of main throttling arrangement 39 because increasing amount of liquid further in this throttling expansion, flowing into evaporimeter 41 and evaporating.Cooling effect is played by the heat-absorbing action produced therefrom.Control device 57, based on the output of not shown temperature sensor detecting the entrance side of evaporimeter 41 and the temperature of outlet side, controls the valve opening of main throttling arrangement 39, the degree of superheat of the cold-producing medium of evaporimeter 41 is adjusted to appropriate value.Refrigeration machine assembly 3 is returned from refrigerant piping 9 from the gas refrigerant of the low temperature of evaporimeter 41 outflow, at the second stream 15B of inner heat exchanger 15 by after the refrigerant cools that flows at first flow path 15A, import pipe arrangement 22 through cold-producing medium and be inhaled into the rudimentary side suction ports 17 be communicated with the first rotary compression element 14 of compressor 11.

Be more than the flowing of major loop 38, the flowing of subsidiary loop 48 is then described.The gas refrigerant lodging in decompression tank 36 internal upper part makes temperature reduce because of the evaporation in decompression tank 36.The gas refrigerant of this decompression tank 36 internal upper part flows out from the gas pipe arrangement 42 forming the subsidiary loop 48 be connected with top, after auxiliary throttling arrangement 43 throttling, flows into the first flow path 29A of separate heat exchanger 29.At this, by after the refrigerant cools that flows at the second stream 29B, return pipe arrangement 44 through centre pressure and press with centre and suck pipe arrangement 26 and collaborate, and being inhaled into the middle splenium of compressor 11.

Control device 57 based on from detecting the not shown temperature sensor of ejection refrigerant temperature of compressor 11, temperature that middle pressure sensor 52, low pressure sensor 51, high pressure sensor 49, the not shown temperature sensor detecting the temperature of the cold-producing medium flowed out from gas cooler 28, module outlet temperature sensor 54 detect and pressure controls the valve opening of auxiliary throttling arrangement 43, and the refrigerant amount that the first flow path 29A at separate heat exchanger 29 flows is adjusted to appropriate value.The valve opening of this auxiliary throttling arrangement 43 also has impact to the pressure in decompression tank 36, so control device 57 adds this auxiliary valve opening of throttling arrangement 43 and the valve opening of controlled pressure adjustment throttling arrangement 33, the pressure (flowing into the pressure of the cold-producing medium of main throttling arrangement 39) in decompression tank 36 is adjusted to set value SP.

In addition, control device 57 is based on the detected pressures (high side pressure HP) of the index and high pressure sensor 49 that represent ambient atmos temperature, when high side pressure (ambient atmos temperature) is lower than cyclic switching value CP, the magnetic valve 47 of open fluid loop 46.If this magnetic valve 47 is open, the liquid refrigerant then lodging in bottom in decompression tank 36 flows out from liquid pipe arrangement 46, collaborate with gas pipe arrangement 42 and flow into auxiliary throttling arrangement 43 (in addition, control device 57 shut electromagnetic valve 47 when high side pressure HP (ambient atmos temperature) rises to more than cyclic switching value CP).

(1-1) action when ambient atmos temperature is high

Use the P-H line chart of Fig. 2 ~ Fig. 4 that the situation of refrigerant loop 1 is now described.When Fig. 2 represents that such as ambient atmos temperature is the environment of more than 30 DEG C.When this ambient atmos temperature is high, high side pressure HP is also high, becomes above-mentioned more than cyclic switching value CP, so control device 57 shut electromagnetic valve 47.Therefore, the gas refrigerant that the temperature in decompression tank 36 is low flows at the first flow path 29A of separate heat exchanger 29, utilizes the liquid refrigerant cooling that cold and hot (sensible heat) of this gas refrigerant will flow at the second stream 29B.In addition, the valve opening of pressure adjustment throttling arrangement 33 is throttle, and auxiliary throttling arrangement 43 is almost full-gear.

The line that X1 ~ X2 in fig. 2 declines represents the decompression that pressure adjustment throttling arrangement 33 produces, at X2 by the tank 36 separating liquids/gas that reduces pressure, from then on after representing improved towards the line on the right side by the enthalpy of the gas refrigerant of auxiliary throttling arrangement 43 throttling of subsidiary loop 48, to the state that the middle splenium of compressor 11 returns, the line towards a left side represents the supercooling towards the liquid refrigerant of the main throttling arrangement 39 of major loop 38.And, at X3 by the throttling of main throttling arrangement 39, pressure drop.Like this, high at extraneous gas temperature, under the situation that high side pressure HP is high, control device 57 shut electromagnetic valve 47, refrigerant loop 1 becomes so-called 2 grades of expansion cycles.

(1-2) action during ambient atmos moderate temperature

Then, when Fig. 3 represents that such as ambient atmos temperature is the environment of about 25 DEG C.Be that high side pressure HP is also low than the situation of Fig. 2 when such ambient atmos moderate temperature, the situation slightly lower than above-mentioned cyclic switching value CP, therefore, the open magnetic valve 47 of control device 57.Therefore, the gas refrigerant of decompression tank 36 internal upper part and the liquid refrigerant both sides of bottom flow to the first flow path 29A of separate heat exchanger 29, utilize the heat-absorbing action that the cold and hot of this gas refrigerant produces with the evaporation of liquid refrigerant, than cooling the liquid refrigerant flowed at the second stream 29B during Fig. 2 more strongly.In addition, the valve opening of pressure adjustment throttling arrangement 33 opens tendency, and auxiliary throttling arrangement 43 is throttle.

The line that X1 ~ X2 in figure 3 declines represents the decompression that pressure adjustment throttling arrangement 33 produces equally, at X2 by the tank 36 separating liquids/gas that reduces pressure, after still from then on representing risen towards the dotted line of right back reduction by the enthalpy of the gas refrigerant of auxiliary throttling arrangement 43 throttling of subsidiary loop 48, return the state of the middle splenium of compressor 11, after declining from X2, represent the change of the liquid refrigerant flowing to subsidiary loop 48 towards the dotted line on the right side.In addition, represent equally towards the supercooling of the liquid refrigerant of the main throttling arrangement 39 of major loop 38 from X2 towards the line on a left side.And, equally, at X3 by the throttling of main throttling arrangement 39, pressure drop.Like this, decline at extraneous gas temperature, under the situation of high side pressure HP step-down, magnetic valve 47 opened by control device 57, so refrigerant loop 1 becomes 2 grades of expansion cycles and so-called separate type circulates and uses circulation.

(1-3) action when ambient atmos temperature is low

Then, when Fig. 4 represents that such as ambient atmos temperature drops to the environment of less than 20 DEG C.When such ambient atmos temperature is low, become high side pressure HP still low than the situation of Fig. 3, the situation significantly lower than above-mentioned cyclic switching value CP, so control device 57 is same with the situation of Fig. 3, open magnetic valve 47.High side pressure HP is become low, the state that the valve opening of pressure adjustment throttling arrangement 33 also increases when such ambient atmos temperature is low.In addition, because be low temperature, so easily liquefy from the cold-producing medium of gas cooler 28 outflow, therefore, the cold-producing medium entering decompression tank 36 through pressure adjustment throttling arrangement 33 almost liquefies, and becomes the state of accumulating a large amount of liquid refrigerants in decompression tank 36.

Open magnetic valve 47 in this state, therefore, in decompression tank 36, the liquid refrigerant of bottom flows at the first flow path 29A of separate heat exchanger 29, utilizes the heat-absorbing action that this liquid refrigerant evaporates produces, than more strongly cooling the liquid refrigerant flowed at the second stream 29B during Fig. 3.In addition, auxiliary throttling arrangement 43 becomes throttle.X1 ~ X3 in Fig. 4 represents point similar to the above, and like this, when extraneous gas temperature is low, refrigerant loop 1 becomes separate type circulation.

Like this, by being flowed out by the top making gas refrigerant from decompression tank 36 and flowing into the gas pipe arrangement 42 of auxiliary throttling arrangement 43 and make liquid refrigerant from reducing pressure tank 36 bottom outflow form the subsidiary loop 48 of the part of the upstream side being positioned at auxiliary throttling arrangement 43 via the liquid pipe arrangement 46 that magnetic valve 47 flows into auxiliary throttling arrangement 43, expanded by pressure adjustment throttling arrangement 33 and liquefy, enter in decompression tank 36, part evaporation, the gas refrigerant that temperature can be made to reduce and remaining liquid refrigerant utilize gas pipe arrangement 42 and the selective first flow path 29A flowing to separate heat exchanger 29 of liquid pipe arrangement 46.

Namely, such as under the environment that the ambient atmos temperature that extraneous gas temperature is high is high, because the high side pressure HP of refrigerant loop 1 also uprises, so the pressure of the cold-producing medium flowing into main throttling arrangement 39 is reduced in set value SP, therefore control device 57 controls in the mode of the valve opening reducing pressure adjustment throttling arrangement 33.In this condition, the liquid refrigerant be stored in decompression tank 36 reduces, and when it flows to the first flow path 29A of separate heat exchanger 29, is difficult to guarantee through the liquid refrigerant of the second stream 29B towards main throttling arrangement 39.

In addition, if ambient atmos temperature reduces and becomes the euthermic environment of ambient atmos, high side pressure HP also declines, then control device 57 has the valve opening opening tendency ground controlled pressure adjustment throttling arrangement 33, and the refrigerant amount be stored in decompression tank 36 also increases.And if ambient atmos temperature declines further and becomes the low environment of ambient atmos temperature, high side pressure HP reduces further, then liquid refrigerant is stored in decompression tank 36 in a large number.

Given this, control device 57 is based on the index and the high side pressure HP that represent ambient atmos temperature, Controlling solenoid valve 47, the shut electromagnetic valve 47 when extraneous gas temperature rises, magnetic valve 47 is opened when extraneous gas temperature reduces, therefore, under the environment that extraneous gas temperature is high, close the magnetic valve 47 of liquid-mixing pipe 46, the gas refrigerant in decompression tank 36 can be made to flow to the first flow path 29A of separate heat exchanger 29 from gas pipe arrangement 42.Thus, the refrigerant cools that the second stream 29B at separate heat exchanger 29 is flowed by the gas refrigerant declined by temperature in decompression tank 36, by after the liquid refrigerant cooling in decompression tank 36 in the second stream 29B of separate heat exchanger 29, main throttling arrangement 39 (2 grades of expansion cycles of Fig. 2) can be supplied.

On the other hand, under the environment that extraneous gas temperature is moderate, open the magnetic valve 47 of liquid pipe arrangement 46, the gas refrigerant in decompression tank 36 and liquid refrigerant can be made to flow to the first flow path 29A of separate heat exchanger 29 from gas pipe arrangement 42 and liquid pipe arrangement 46 both sides.Thus, not only utilize the gas refrigerant (sensible heat) that temperature declines in decompression tank 36, and utilize and to be expanded by auxiliary throttling arrangement 43 and the latent heat of liquid refrigerant in first flow path 29A evaporation, by the refrigerant cools of the major loop 38 that the second stream 29B at separate heat exchanger 29 flows, after the liquid refrigerant that cooling is reduced pressure in tank 36 more strongly in the second stream 29B of separate heat exchanger 29, main throttling arrangement 39 (2 grades of expansion cycles of Fig. 3 and separate type circulate and use circulation) can be supplied.

And, even if under the environment that extraneous gas temperature is low, by opening the magnetic valve 47 of liquid pipe arrangement 46, the liquid refrigerant be stored in a large number in decompression tank 36 also can be made from liquid pipe arrangement 46 to flow to the first flow path 29A of separate heat exchanger 29.Thus, utilize and expanded by auxiliary throttling arrangement 43 and more strongly cool the cold-producing medium flowed at the second stream 29B of separate heat exchanger 29 at the latent heat of the liquid refrigerant of first flow path 29A evaporation, after strongly being cooled in the second stream 29B of separate heat exchanger 29 by liquid refrigerant in decompression tank 36, main throttling arrangement 39 (the separate type circulation of Fig. 4) can be supplied.

Like this, 2 grades of expansion cycles and separate type circulation can be switched according to ambient atmos temperature environment, so can the more stable and refrigerating plant R of operating efficiently.

At this, Fig. 5 represents the control of changing above-mentioned cyclic switching value CP according to the evaporating temperature of the cold-producing medium of evaporimeter 41.Control device 57 is based on the index of evaporating temperature of the cold-producing medium represented in evaporimeter 41 and the detected pressures (low-pressure lateral pressure LP) of low pressure sensor 51, change as follows as illustrated in fig. 5, the evaporating temperature of evaporimeter 41 is higher, more reduces cyclic switching value CP.Thus, higher in the evaporating temperature of the cold-producing medium of evaporimeter 41, when high side pressure HP (ambient atmos temperature) is lower, magnetic valve 47 cuts out, and refrigerant loop 1 becomes 2 grades of expansion cycles.Namely, showcase 4 is situations etc. of refrigerating display case, under the condition that the evaporating temperature of the cold-producing medium of evaporimeter 41 is low, magnetic valve 47 is opened by higher high side pressure HP (ambient atmos temperature), in the situation etc. of refrigerator display case, under the condition that the evaporating temperature of evaporimeter 41 is high, shut electromagnetic valve 47, until high side pressure HP (ambient atmos temperature) becomes lower.

Like this, by control device 57, based on index and the low-pressure lateral pressure LP of the evaporating temperature of the cold-producing medium represented in evaporimeter 41, this evaporating temperature is higher, with lower ambient atmos temperature shut electromagnetic valve 47, thus, in the running of the high state of the evaporating temperature of the such as refrigerated condition of refrigerator etc., when ambient atmos temperature increases, 2 grades of above-mentioned expansion cycles are switched to step faster, can guarantee, towards the liquid refrigerant of main throttling arrangement 39, the refrigerating capacity under refrigerated condition can be maintained.

On the other hand, under cryogenic conditions reach in freezer as low in evaporating temperature etc. etc., the supercooling of the cold-producing medium flowing into main throttling arrangement 39 in separate heat exchanger 29 is not needed in above-mentioned 2 grades of expansion cycles, but owing to improving cyclic switching value CP, as far as possible with separate type cycle operation, so effectively the cold-producing medium supercooling of main throttling arrangement 39 can will be flowed into.Thus, when operating with different evaporating temperatures, also can realize the running efficiency optimization of refrigerating plant R.

In addition, by arranging pressure adjustment throttling arrangement 33, the stream of refrigerant loop 1 becomes the mode of cut-off, therefore, and the danger that the high side pressure with the refrigerant loop 1 of its upstream side increases.Therefore, control device 57 is based on detecting the output of specific pressure adjustment throttling arrangement 33 by the high pressure sensor 49 of the high side pressure HP of the refrigerant loop 1 of upstream side, when high side pressure HP rises to set upper limit value HHP (such as 10.5MPa), regardless of the set value SP of the pressure in above-mentioned decompression tank 36, the valve opening of pressure adjustment throttling arrangement 33 is all made to increase.

Control device 57 is programmed in such a way; namely; originally when the pressure increase that high pressure sensor 49 detects protects stop value to such as 11.5MPa etc.; perform the protection act stopping compressor 11; increase by making the valve opening of pressure adjustment throttling arrangement 33 as described above; although how much pressure in decompression tank 36 rises, specific pressure adjustment throttling arrangement 33 does not improve further by the high side pressure HP of upstream side.Thereby, it is possible to the stopping (protection act) of the compressor 11 avoiding abnormal pressure to cause in advance.

As described in detail above, refrigerant loop 1 is formed by compressor 11, gas cooler 28, main throttling arrangement 39, evaporimeter 41, be possess in the refrigerating plant R of supercritical pressure in high-pressure side: pressure adjustment throttling arrangement 33, it is connected with the refrigerant loop 1 of the downstream of gas cooler 28 and the upstream side of main throttling arrangement 39, decompression tank 36, it is connected with the refrigerant loop 1 of pressure adjustment with the downstream of throttling arrangement 33 and the upstream side of main throttling arrangement 39, separate heat exchanger 29, it is located at the refrigerant loop 1 of the decompression downstream of tank 36 and the upstream side of main throttling arrangement 39, subsidiary loop 48, it is making after the cold-producing medium in decompression tank 36 flows to the first flow path 29A of separate heat exchanger 29 via auxiliary throttling arrangement 43, to be drawn into the middle splenium of compressor 11, major loop 38, it makes cold-producing medium flow out from decompression tank 36 bottom, flow to the second stream 29B of separate heat exchanger 29 and after the cold-producing medium that itself and first flow path 29A are flowed carried out heat exchange, it is made to flow into main throttling arrangement 39, therefore, by auxiliary throttling arrangement 43, the cold-producing medium of the first flow path 29A flowing at the separate heat exchanger 29 forming subsidiary loop 48 is expanded, can by the refrigerant cools of the flowing of the second stream 29B of the separate heat exchanger 29 at formation major loop 38, reduce the specific enthalpy of evaporimeter 41 entrance, effectively can improve refrigerating capacity.

In addition, the cold-producing medium flowed at the first flow path 29A of separate heat exchanger 29 returns the middle splenium of compressor 11, so the refrigerant amount being inhaled into the low voltage section of compressor 11 reduces, the compression horsepower for the compressor 11 being compressed to middle pressure from low pressure reduces.Its result, the compression power of compressor 11 reduces, and the coefficient of performance improves.

Particularly, at pressure adjustment throttling arrangement 33, the cold-producing medium flowed out from gas cooler 28 expanded and make it flow in decompression tank 36, therefore, the pressure of the cold-producing medium flowing into main throttling arrangement 39 is reduced by this pressure adjustment throttling arrangement 33, thus, can use as the refrigerant piping 8 reaching main throttling arrangement 39 pipe arrangement that compressive resistance is low.In addition, also have by the effect of the variation of the circularly cooling dosage in decompression tank 36 absorption refrigeration agent loop 1.Therefore, when refrigerant charge amount is too much, also absorbed with appropriate error.Therefore, application property when can also realize refrigeration machine assembly 3 and the showcase 4 of settling refrigerating plant R in shop and the improvement of construction cost.

In addition, part evaporation in decompression tank 36 of the cold-producing medium liquefied by utilizing pressure adjustment throttling arrangement 33 to expand, become the gas refrigerant that temperature reduces, remaining is liquid refrigerant, is stored in bottom in decompression tank 36 for the time being.And, in this decompression tank 36, the second stream 29B of the separate heat exchanger 29 of liquid refrigerant through forming major loop 38 of bottom flows into main throttling arrangement 39, therefore, the switching of above-mentioned circulation also completes, flow of refrigerant can be made under full liquid status to become owner of throttling arrangement 39, particularly can realize the raising of the refrigerating capacity of the high refrigerated condition of the evaporating temperature of evaporimeter 41 (refrigerator display case etc.).

Particularly, control device 57 controlled pressure regulates the valve opening with throttling arrangement 33, the pressure of the cold-producing medium flowing into main throttling arrangement 39 is adjusted to the setting SP of regulation, so the change of the ambient atmos temperature because of the transition along with season can be prevented, flow into the more cataclysmal situation of pressure of the cold-producing medium of main throttling arrangement 39, identical set value SP can be always maintained at.Thus, particularly under the refrigerated condition (refrigerator display case etc.) that the evaporating temperature of evaporimeter 41 is high, the control stabilisation of main throttling arrangement 39 can be made and stably guarantee refrigerating capacity.Particularly effectively improve as the embodiment as refrigerating capacity during cold-producing medium use carbon dioxide, the raising of performance can be realized.

(2) function of inner heat exchanger 15

Then, the control of the magnetic valve 50 of control device 57 is described.As described above, in inner heat exchanger 15, can will flow at first flow path 15A by the cold-producing medium of the low temperature from evaporimeter 41 outflow flowed at the second stream 15B and flow into the refrigerant cools of main throttling arrangement 39, so the specific enthalpy of evaporimeter 41 entrance can be reduced further, effectively improve refrigerating capacity further.

Particularly, in the environment that the ambient atmos temperature that ambient atmos temperature is as shown in Figure 2 high is high, there is not the pressure (pressure of the X2 of Fig. 2) be adjusted in the decompression tank 36 of setting SP by pressure adjustment throttling arrangement 33 and press with the centre entering compressor 11 the middle pressure differential of pressing (MP) sucking pipe arrangement 26.In this situation, auxiliary throttling arrangement 43 is almost full-gear as described above, so according to the difference of situation, almost can not by the cold-producing medium supercooling of the major loop 38 in the second stream 29B flowing by the cold-producing medium of the subsidiary loop 49 flowed at the first flow path 29A of separate heat exchanger 29.

In this condition, arrive the state of the cold-producing medium of main throttling arrangement 39 through the second stream 29B of separate heat exchanger 29 on the cardinal principle saturated liquid line in Fig. 2 shown in X4, liquid is few, is almost the state of gas.Therefore, by the pressure of the cold-producing medium of main throttling arrangement 39 throttling as shown in dotted line in this figure, decline from the X4 of Fig. 2.Like this, reduced by the enthalpy difference below, refrigerating capacity reduces.

But, in an embodiment, by will the refrigerant cools of main throttling arrangement 39 be flowed into from the cold-producing medium of the low temperature of evaporimeter 41 outflow in inner heat exchanger 15, as shown in X3 in Fig. 2, can from the supercooling of saturated liquid line to the supercooling territory in left side, so to main throttling arrangement 39 the supply system cryogen under the full liquid status that liquid is many, the improvement of refrigerating capacity also can be realized under this situation.

(2-1) control of magnetic valve 50

On the other hand, when refrigerating plant R drops etc., there is the situation that the temperature of the cold-producing medium flowed out from evaporimeter 41 is higher than the cold-producing medium flowing into main throttling arrangement 39.Therefore, the temperature OT of the cold-producing medium of the second stream 15B outflow from inner heat exchanger 15 that the temperature IT of the cold-producing medium of the first flow path 15A of the inflow inner heat exchanger 15 that control device 57 detects based on module outlet temperature sensor 54 and module inlet temperature sensor 56 detect, when IT < OT, open magnetic valve 50 (when IT >=OT, magnetic valve 50 cuts out).

Thus, cold-producing medium the first flow path 15A bypass of inner heat exchanger 15 is made to flow at bypass circulation 45 and flow into main throttling arrangement 39, therefore, it is possible to eliminate the unfavorable condition being heated the cold-producing medium flowing into main throttling arrangement 39 by the cold-producing medium flowed out from evaporimeter 41 conversely in advance.

In addition, in an embodiment, be connected in parallel bypass circulation 45 with the first flow path 15A of inner heat exchanger 15, but be not limited thereto, also bypass circulation and magnetic valve can be set in parallel with the second stream 15B.

Claims

1. a refrigerating plant, form refrigerant loop by compression set, gas cooler, main throttling arrangement, evaporimeter, high-pressure side is supercritical pressure, it is characterized in that, possesses:

Pressure adjustment throttling arrangement, it is connected with the described refrigerant loop of the downstream of described gas cooler and the upstream side of described main throttling arrangement;

Decompression tank, itself and described pressure regulate and are connected with the described refrigerant loop of the downstream of throttling arrangement and the upstream side of described main throttling arrangement;

Separate heat exchanger, it is located in the described refrigerant loop of the downstream of described decompression tank and the upstream side of described main throttling arrangement;

Subsidiary loop, described cold-producing medium is drawn into the middle splenium of described compression set flow to the first flow path of separate heat exchanger via auxiliary throttling arrangement after by its cold-producing medium in described decompression tank;

Major loop, it flows out from described decompression tank bottom making cold-producing medium, flows to the second flow path of described separate heat exchanger and after having carried out heat exchange with the cold-producing medium flowed in described first flow path, makes described cold-producing medium flow into described main throttling arrangement.

2. refrigerating plant as claimed in claim 1, is characterized in that,

Possess the control device controlling described pressure adjustment throttling arrangement,

The pressure of the cold-producing medium flowing into described main throttling arrangement, by controlling the aperture of described pressure adjustment throttling arrangement, is adjusted to the setting of regulation by described control device.

3. refrigerating plant as claimed in claim 2, is characterized in that,

Described control device, when the high side pressure of the described refrigerant loop than described pressure adjustment throttling arrangement upstream side rises to set upper limit value, makes the aperture of described pressure adjustment throttling arrangement increase.

4. the refrigerating plant according to any one of claims 1 to 3, is characterized in that,

The described subsidiary loop of the upstream side of described auxiliary throttling arrangement is by making cold-producing medium flow out from described decompression tank top and flowing into the gas pipe arrangement of described auxiliary throttling arrangement and make cold-producing medium flow out from described decompression tank bottom and form via the liquid pipe arrangement that valve gear flows into described auxiliary throttling arrangement.

5. refrigerating plant as claimed in claim 4, is characterized in that,

Described control device, based on valve gear described in the norm controlling representing ambient atmos temperature, when described ambient atmos temperature rises, cuts out described valve gear, when described ambient atmos temperature reduces, opens described valve gear.

6. refrigerating plant as claimed in claim 5, is characterized in that,

Described control device based on the evaporating temperature of the cold-producing medium represented in described evaporimeter norm controlling described in valve gear, described evaporating temperature is higher, closes described valve gear with lower ambient atmos temperature.

7. the refrigerating plant according to any one of claim 1 ~ 6, is characterized in that,

Be provided with the cold-producing medium making the described main throttling arrangement of inflow and the inner heat exchanger carrying out heat exchange from the cold-producing medium that described evaporimeter flows out.

8. refrigerating plant as claimed in claim 7, is characterized in that,

The first flow path that described inner heat exchanger possesses the flow of refrigerant flowing into described main throttling arrangement and the second stream of flow of refrigerant flowed out from described evaporimeter, make the cold-producing medium that flows in the first flow path of described inner heat exchanger and carry out heat exchange at the cold-producing medium of the second flow path of described inner heat exchanger, and

Possess the bypass circulation be connected in parallel with the second stream of the first flow path of described inner heat exchanger or described inner heat exchanger and the bypass valve gear being located at this bypass circulation.

9. refrigerating plant as claimed in claim 8, is characterized in that,

Possess the control device controlling described bypass valve gear,

This control device is based on the temperature of the cold-producing medium of first flow path and the cold-producing medium from the second stream outflow of described inner heat exchanger that flow into described inner heat exchanger, when the temperature of the cold-producing medium flowed out from the second stream of described inner heat exchanger is higher than the temperature of the cold-producing medium of the first flow path of the described inner heat exchanger of inflow, open described bypass valve gear.

10. the refrigerating plant according to any one of claim 1 ~ 9, is characterized in that,

As described cold-producing medium, use carbon dioxide.