CN1761848A

CN1761848A - System and method for stepped capacity modulation in a refrigeration system

Info

Publication number: CN1761848A
Application number: CNA2004800072837A
Authority: CN
Inventors: 约瑟夫·洛普雷特
Original assignee: Bristol Compressors Inc
Current assignee: Bristol Compressors Inc
Priority date: 2003-01-24
Filing date: 2004-01-23
Publication date: 2006-04-19
Also published as: US20040148951A1

Abstract

A control system is provided for generating discrete stepped output capacities in a refrigeration system. The refrigeration system is preferably a multi-evaporator system having two or more multi-capacity compressors. The multi-capacity compressors can be any kind of reciprocating compressor or scroll compressor that can provide two or more different output capacities. The contributions of the compressors to the overall system capacity can be equal, or more preferably, they can be unequal, i.e., one compressor provides more capacity than the other compressor(s). The control system generates the stepped capacities of the refrigeration system by configuring and controlling the operation of the compressors and the output capacity provided by the compressors.

Description

The system and method that is used for the modulation of refrigeration system hierarchy capacity

Mutual CROSS-REFERENCE TO RELATED APPLICATION

The application's request enjoys in the priority of No. 60/442,215, the U.S. Provisional Application submitted on January 24th, 2003.

Background technology

Present invention relates in general to a kind of refrigeration system with classification output capacity (stepped output capacities).More particularly, the present invention relates to a kind of control system, it can provide eight kinds or more kinds of discontinuous output capacity for the refrigeration system of compressor with two-stage or more multistage capacity.

(dual capacity compressor) can be the output capacity that refrigeration system provides different brackets with dual capacity.Using a shortcoming of dual capacity is that refrigeration system may need the different output capacity of one of capacity with this compressor, therefore, may cause on the one hand the capacity that produces excessive according to selected compressor configuration (configuration), perhaps may cause the off-capacity that produces on the other hand.

In addition, the output capacity that is used for the different brackets of refrigeration system can obtain by the operation that control be arranged on the compressor of many single capacity in the refrigeration system.United States Patent (USP) 4,384,462 (`462 patents) number disclose a kind of like this system.The `462 patent relates to a kind of multi-stage compression machine cooling system, the compressor that it has many different capabilities with a plurality of link to each other with compressor be in evaporimeter in the different involucrums (enclosure).These compressors have single capacity, and can switch between " connection " state and " disconnection " state.Compressor will cause refrigeration system to be in 2 with the switching of various combination between " connection " and " disconnection " state ^NPlant different brackets or running status, also comprise the nought state when all compressors are in " disconnection ".This control can or reduce to increase or reduce the specific run state of refrigeration system according to the increase of the pressure of inspiration(Pi) of system.

In addition, the output capacity of the different brackets of refrigeration system can obtain by the operation that is arranged on many dual capacity in the refrigeration system is sorted.A kind of by United States Patent (USP) 4,501 in this type systematic, 125 (`125 patents) are number disclosed.The `125 patent relates to a kind of humidity control system.This humidity control system is provided with two two-stage compressors that link to each other with evaporimeter in the refrigerating circuit.The `125 patent has been discussed the situation that can obtain the level Four cooling when using two two-stage compressors.This system increases or reduces cooling (heating) level or cooling (heating) state according to the preassigned in the lookup table (look-up table).

Therefore, need a kind of system and method that the classification output capacity is provided in having the refrigeration system of two or more multistage capacity compressors, to satisfy the required specific output capacity of refrigeration system.

Summary of the invention

One embodiment of the present invention relates to a kind of refrigeration system with multiple compressors.Each compressor in the multiple compressors is configured to provide multiple discontinuous output capacity.Refrigeration system also comprises condenser and at least one evaporimeter that is communicated with condenser and described multiple compressors fluid that is communicated with the multiple compressors fluid.Control system is used to control the operation (starting or shut down) of each compressor of multiple compressors, so that a kind of discontinuous output capacity in the multiple discontinuous output capacity of each compressor in the control multiple compressors.Control system is according to the discontinuous output capacity of the compressor of each operation in definite compressor that should move of the required output capacity of refrigeration system and the multiple compressors.

Another embodiment of the present invention relates to the methods of many multistage capacity compressor operations in the refrigeration system that a kind of control has at least one evaporimeter.This method comprises the step of the configuration of many multistage capacity compressors of determining the output capacity that refrigeration system is required and being identified for producing the output capacity that is determined.The configuration of the multistage capacity compressor that is determined is from being used for many multistage capacity compressors, having that the form of the various configurations of compressor operating and compressor capacity obtains.Each configuration in the various configurations is all corresponding to a kind of output capacity of refrigeration system.This method comprises that also the configuration of many multistage capacity compressors that will be determined is applied to many compound compressors, to produce the step of the output capacity that is determined in refrigeration system.

Another embodiment of the invention relates to a kind of refrigeration system, and it has multiple compressors, the condenser that is communicated with the multiple compressors fluid, evaporimeter that at least one is communicated with condenser and multiple compressors fluid and according to the control system of the required output capacity control multiple compressors of refrigeration system.Described multiple compressors has multiple predetermined running configuration, and each the predetermined running configuration in the wherein multiple predetermined running configuration all can be refrigeration system provides predetermined output capacity.Control system is configured to: from multiple predetermined running configuration, select a kind of predetermined running configuration, to satisfy required output capacity most effectively.Every compressor in the multiple compressors all has multiple discontinuous output capacity, and the configuration of every kind of predetermined running of multiple compressors all comprises the discontinuous output capacity of the compressor of the running status of every compressor of multiple compressors and each operation.

An embodiment more of the present invention relates to a kind of method of controlling many multistage capacity compressor operations in the refrigeration system.This method comprises providing to have refrigeration system that is connected many multistage capacity compressors, condenser and a plurality of evaporimeters in the closed refrigerant loop and the step of determining the output capacity that this refrigeration system is required.This method also comprises the configuration of the multistage capacity compressor of determining to have predetermined output capacity, to satisfy the step of the required output capacity that is determined.Every multistage capacity compressor of described many multistage capacity compressors all has multiple discontinuous output capacity, and the configuration of many multistage capacity compressors that are determined comprises the discontinuous output capacity of the multistage capacity compressor of the running status of each compressor of many multistage capacity compressors and each operation.This method also comprises the configuration control instruction corresponding that produces with many multistage capacity compressors that are determined, to control the step that many multistage capacity compressors produce the predetermined output capacity that is used for refrigeration system.

An advantage of the present invention is various output capacity can be provided, so that be complementary with the required output capacity of refrigeration system more accurately, thereby can avoid producing useless excessive capacity.

From below in conjunction with accompanying drawing and by the shown principle of the invention of example to being clear that other features and advantages of the present invention more the more detailed description of preferred implementation.

Description of drawings

Fig. 1 schematically shows an embodiment of refrigeration system of the present invention;

The form of Fig. 2 shows the level of output capacity and the corresponding configuration of two dual capacity being produced by control system of the present invention;

The form of Fig. 3 shows by several different output capacities that compressor configuration provided;

Fig. 4 is the flow chart of control procedure of the present invention.

As possible, all representing same or analogous parts with identical Reference numeral in the accompanying drawing.

The specific embodiment

In Fig. 1, show and to use conventional system of the present invention by means of example.As shown in the drawing, heating, heating ventilation and air-conditioning (HVAC) or refrigeration system 100 comprise first compressor 102, second compressor 104, condenser 106, one or more evaporimeter 108, (or a plurality of) expansion gear 110 and a control panel 140.Control panel 140 can comprise analog to digital (A/D) converter, microprocessor, nonvolatile memory and interface board.Below with the operation of description control panel 140 in more detail.Traditional refrigeration or HVAC system 100 also comprise many other unshowned features in Fig. 1.For simplifying accompanying drawing so that explanation has a mind to omit these features.

In refrigeration system 100,

compressor

102 and 104 compress refrigerant vapor also make compressed refrigerant vapour be delivered to condenser 106 by

single pipeline.Compressor

102 and 104 output interconnect, so that mix in single pipeline from the compressed cold-producing medium vapour of each

compressor

102 and 104, are transported to condenser 106 subsequently.In addition, have only in

compressor

102 and 104 under the situation of compressor operation,

other compressors

102 and 104 output are closed or are sealed by the valve (not shown), to prevent that cold-producing medium from passing through off-

duty compressor

102 and 104 and refluxing.The

compressor

102 and 104 preferably multistage capacity that has of any kind is exported, is the reciprocating type or scroll compressor of two or more discontinuous output capacity levels.Certainly, be contemplated that the present invention can use the compressor of any kind that two or more discontinuous output capacities can be provided.

In another embodiment of the present invention, can separately carry and keep separately from the compressed cold-producing medium vapours of each

compressor

102 and 104 outputs, when the cold-producing medium vapour of output mixes in condenser 106 till.In another embodiment of the invention, can independently carry the refrigerant loop from the compressed cold-producing medium vapour of each

compressor

102 and 104 outputs, promptly when cold-producing medium when the systemic circulation, do not mix with compressed cold-producing medium vapour from the compressed cold-producing medium vapour of a compressor from another compressor.In this embodiment, condenser in each loop and evaporimeter can have any suitable layout, cause when still keeping independently cold-producing medium circulation, carry out necessary heat exchange.

In Fig. 1, flow through or carry out heat exchange with the fluid of air or water preferably when flowing around the heat exchanger coil in the condenser 106 from the cold-producing medium vapour of compressor 102 and 104.As the result who carries out heat exchange with described fluid, the cold-producing medium vapour in the condenser 106 becomes refrigerant liquid through phase transformation.The liquid refrigerant that is condensed flows through expansion gear 110 (one or more) from condenser 106 and arrives evaporimeter 108.Expansion gear (one or more) 110 can be the suitable device that highly pressurised liquid is transformed into low pressure liquid and vapour of any kind of, for example expansion valve or capillary.

Then, according to the concrete configuration of refrigeration system 100, the output of expansion gear (one or more) 110 is offered one or more evaporimeters 108.Can according to the specific cooling requirement of refrigeration system 100 or output capacity demand (below will discuss in more detail) be closed one or more evaporimeters 108 or stop using.The valve (not shown) at the entrance and exit place by being arranged on each inactive evaporimeter 108 can prevent that refrigerant liquid and/or vapour from entering inactive evaporimeter 108.In another embodiment of the present invention, the pipeline that picks out from expansion gear 110 can be connected on the branch road that is provided with the suitable valve that links to each other with each evaporimeter 108.Branch road can be configured or operated to suitable evaporimeter 108 cold-producing medium is provided.Similarly, the output of evaporimeter 108 can be connected on the branch road that is provided with suitable valve, and this branch road only can be configured or operated to and provide the cold-producing medium vapour with single pipeline to compressor 102 and 104.No matter be on pipeline independently or on branch road, evaporimeter 108 stop using and closing all of valve can be controlled individually by central control system control or at each evaporimeter 108 place.

From the refrigerant liquid of expansion gear 110 with gasification streams is crossed or carry out heat exchange with the fluid of air preferably when flowing around the heat exchanger coil of the evaporimeter 108 of each operation, to reduce the temperature of air.Owing to carry out heat exchange with air, the refrigerant liquid phase transformation in the evaporimeter 108 becomes refrigerant vapour.Cold-producing medium vapour in the evaporimeter 108 flows out evaporimeter 108 and turns back to compressor 102 and 104 by common pall by air-breathing connector, thereby finishes circulation.The quantity of the evaporimeter 108 in refrigeration system 100 can change to N from one, wherein N preferably with the corresponding number (below will discuss in more detail) of maximum progression of the classification output of compressor 102 and 104.But in another embodiment of the present invention, the quantity of evaporimeter can be greater than the progression of the classification of compressor 102 and 104 output, and promptly N is greater than the maximum progression of classification output.In this embodiment, because the quantity of the sum of series evaporimeter of classification output is identical in this embodiment, the output of evaporimeter and the output of compressor do not match.For example, if compressor shown in Figure 1 102 and 104 is two dual capacity, then N is preferably eight (referring to Fig. 2), and eight (perhaps can be more) evaporimeters 108 can be set in refrigeration system 100.

In another embodiment of the present invention, can increase the platform number of

compressor

102 and 104 and/or the capacity number that provides by each

compressor

102 and 104 can be provided, offer the total amount (below will discuss in more detail) of the classification output capacity of refrigeration system 100 with increase.Correspondingly, because output capacity progression increases,, thereby can keep the best ratio of an evaporimeter and a kind of output capacity level so the evaporimeter 108 that can be used in the refrigeration system 100 is in optimal number (N).

Control panel 140 has A/D converter, to receive the input signal from symbol system 100 performances of system 100 preferablyly.Control panel 140 also has interface board, signal being transferred to the parts of system 100, thus the operation of control system 100.For example, control panel 140 can transmit signal with quantity that controls the evaporimeter that moves and the operation of controlling compressor 102 and 104.Control panel 140 also can comprise many further feature and parts of not discussing here.So that discuss, have a mind to omit these features and parts for simplifying control panel 140.

Control panel 140 is to use the part of the control system of control algolithm (one or more) or software, and it is used for the operation of control system 100 and determines and carry out operation configuration for

compressor

102 and 104 according to the demand of the specific output capacity of system 100.In addition, control system can be utilized control algolithm (one or more) opening and closing valve, thereby evaporimeter 108 is inserted or operation and disengagement or inactive.In one embodiment, control algolithm (one or more) can be computer program or the software that is stored in the nonvolatile memory of control panel 140, and can comprise the instruction group of being carried out by the microprocessor of control panel 140.Though preferably control algolithm is included in the computer program (one or more) and carries out, it will be appreciated that control algolithm also can be finished with numeral and/or analog hardware and realized by those skilled in the art by microprocessor.If realize control algolithm, can change the corresponding configuration of control panel 140, to set up necessary parts and to remove any parts that no longer need with hardware.

The compressor 102 and 104 and by the output capacity of controlling operating compressor 102 and 104 produce the not at the same level output capacity that be used for refrigeration system 100 of control system of the present invention by being controlled at special time operation.By the operation of control compressor and their output capacity, control system of the present invention can produce the output capacity not at the same level that is used for refrigeration system 100.Fig. 2 shows and is used to obtain the compressor shown in Figure 1 102 of eight kinds of discontinuous levels and 104 operation configuration.Compressor 102 and 104 shown in Figure 1 is dual capacity, it have total output capacity that compressor 102 and 104 are provided half the first order and the second level of total output capacity of compressor 102 and 104 is provided.As seeing among Fig. 2, can produce or obtain four kinds of discontinuous levels by in two kinds of operational modes a kind of, making a compressor 102 and 104 operations; Can produce or obtain four kinds of other discontinuous levels by in two kinds of operational modes a kind of, two compressors 102 and 104 all being moved.Be understood that compressor 102 and 104 customized configuration can be associated with any specific step, Fig. 2 just is used to illustrate with the related situation shown in 3.But these sequence of steps are preferably identical with the order that increases power system capacity.

When adding other compressor in refrigeration system 100, control system of the present invention (and the control flow chart among Fig. 2) will be expanded, so that provide additional control configuration for new compressor (one or many).For example, other new compressor can produce the newly-increased level of the first order output that is used for new compressor and second level output and newly-increased grade that the output of new compressor and

compressor

102 and 104 one or two s' output is combined.Similarly, if replace one of

compressor

102 and 104 with multistage capacity compressor with three kinds or more kinds of discontinuous output capacities, control system then of the present invention (and the control flow chart among Fig. 2) will be expanded, so that dispose for the new compressor capacity provides additional control.

In order to further specify the operation of control system of the present invention, the output capacity level of Fig. 2 is applied to several

different compressors

102 and 104 configuration.Fig. 3 provides the output capacity of eight grades each grade that is used for four kinds of different compressor configuration.These four kinds of different compressor configuration comprise: a compressor provide total system capacity 40%, other compressor provides 60% configuration of total system capacity, for example capacity is the compressor that two tons compressor and capacity are three tons; One compressor provide total system capacity 30%, other compressor provides 70% configuration of total system capacity, for example capacity is the compressor that one ton compressor and capacity are two and 1/3rd tons; One compressor provide total system capacity 20%, other compressor provides 80% configuration of total system capacity, for example capacity is the compressor that one ton compressor and capacity are four tons; And every compressor all provides 50% configuration of total system capacity, and for example a pair of capacity is two tons a compressor.

As can be seen from Figure 3, if adopt the

compressor

102 and 104 of the different capabilities have control system of the present invention, can produce eight kinds of different output capacities by eight grades or eight kinds of configurations.Yet,, can only produce four kinds of different output capacities by eight grades or eight kinds of configurations if adopt

compressor

102 and 104 with identical output capacity.This is because the identical output capacity of some grades generation.Therefore, in preferred implementation of the present invention,

compressor

102 and 104 has different output capacities, so that obtain maximum output capacity levels.Can be according to the minimum and maximum demand of refrigeration system 100 and specific total output capacity of and

selection compressor

102 and 104 definite according to the specific output capacity level of user's expectation.

Fig. 4 shows the method for the suitable output capacity of determining refrigeration system 100.This method is from determining the step 402 of refrigeration system 100 required output capacities.The required output capacity of refrigeration system 100 is relevant with the cooling requirement of evaporimeter (one or more) 108.This cooling requirement can be the function, two of quantity of evaporimeter of function, operation of fluid temperature (F.T.) to be cooled or the combination of any other suitable factor.For example, in refrigeration system shown in Figure 1 100, cooling requirement is moving and other three situations that evaporimeter 108 does not move based on five evaporimeters 108.This can appear in the situation in the building for example, and wherein each evaporimeter 108 is all to the specific region of building cooling.

Behind the output capacity of having determined refrigeration system 100 in step 402, in step 404, control system is determined the configuration of

compressor

102 and 104, to satisfy or to satisfy most effectively required output capacity best.The information of the relevant compressor configuration that the control system assessment stores is as the information among Fig. 2, to determine suitable compressor configuration.Can utilize control system that the information about compressor configuration is stored in any suitable mode quick and retrieval easily.Can be in form, database or any other suitable configuration with information storage.In one embodiment, control system can associate the quantity of the evaporimeter 108 of operation with the corresponding steps with a kind of configuration, to produce suitable output capacity.Return in the example of above-mentioned five evaporimeters 108 operations, control system can be selected level 5, and the quantity Matching of this grade and the evaporimeter 108 of operation also has the compressor configuration of the suitable output capacity of generation.In another embodiment, configuration and capacity corresponding that control system can be specific with required output capacity and each are compared, and mate most to determine any configuration and capacity and required output capacity.For example, if required output capacity corresponding to 50% total capacity, control system will compare the output capacity of each configuration, to determine and the 50% required the most approaching configuration of output capacity is provided.

At last, in step 404, the compressor configuration after control system adopt to be determined is also sent appropriate control signals to compressor 102 and 104.Then, the control signal that

compressor

102 and 104 sends according to control system is by required configuration operation, thereby obtains required output capacity.

Though described the present invention with reference to preferred implementation, it will be understood by those skilled in the art that under the prerequisite that does not exceed scope of the present invention, can carry out various changes and its parts are equal to replacement.In addition, under the prerequisite that does not break away from basic design of the present invention, can carry out various conversion in accordance with the teachings of the present invention, to adapt to specific situation or material.Therefore, the present invention is not limited to implement the disclosed specific embodiment of best mode of the present invention, and the present invention should comprise all embodiments that fall in the claims scope.

Claims

1. A refrigeration system comprising:

a plurality of compressors having a plurality of predetermined operating configurations, wherein each predetermined operating configuration of the plurality of predetermined operating configurations produces a predetermined output capacity for the refrigeration system;

a condenser in fluid communication with the plurality of compressors;

at least one evaporator in fluid communication with the condenser and the plurality of compressors;

a control system for controlling said plurality of compressors according to a desired output capacity of said refrigeration system, the control system being adapted to select a predetermined operating configuration from a plurality of predetermined operating configurations to most efficiently satisfy said refrigeration system required output capacity;

wherein each compressor of the plurality of compressors has a plurality of discrete output capacities, and each predetermined operating configuration of the plurality of compressors includes a A compressor operating state and a discrete output capacity for each operating compressor.

2. The refrigeration system of claim 1, wherein said at least one evaporator comprises a plurality of evaporators, and the total number of said plurality of evaporators is equal to the total number of said plurality of predetermined operating configurations.

3. The refrigeration system according to claim 2, wherein said control system includes a memory storing a plurality of predetermined operating states, and the order of said plurality of predetermined operating states is the same as the order of increasing output capacity in said memory .

4. The refrigeration system of claim 3, wherein a preselected number of evaporators of said plurality of evaporators are controlled to operate by said control system according to a predetermined operating configuration selected by said plurality of compressors, and said The preselected number of evaporators corresponds to a sequence identifier for the selected predetermined operating configuration of the plurality of compressors.

5. The refrigeration system of claim 1, wherein each compressor of said plurality of compressors comprises a two-stage capacity compressor having a first discrete output capacity and a second discrete output capacity.

6. The refrigeration system of claim 5, wherein said plurality of compressors includes a first compressor and a second compressor.

7. The refrigeration system of claim 6, wherein said plurality of predetermined operating states includes eight operating states.

8. The refrigeration system of claim 7, wherein said eight operating states are configured to provide eight discrete levels of output capacity for said refrigeration system.

9. The refrigeration system of claim 6, wherein the first compressor and the second compressor are reciprocating compressors.

10. The refrigeration system of claim 5 wherein said second discrete output capacity is greater than said first discrete output capacity, said second discrete output capacity of said first compressor being greater than said second discrete output capacity The second discrete output capacity of the compressor.

11. A method for controlling the operation of multiple multi-stage capacity compressors in a refrigeration system, the method comprising the following steps:

providing a refrigeration system having a plurality of multi-stage capacity compressors, a condenser and a plurality of evaporators connected in a closed refrigeration circuit;

Determine the required output capacity of the refrigeration system;

determining a configuration of the plurality of multi-capacity compressors having predetermined output capacities to meet the determined desired output capacity, each multi-capacity compressor of the plurality of multi-capacity compressors having a plurality of different Continuous output capacity, wherein the determined configuration of the plurality of multi-stage capacity compressors includes the operating status of each compressor of the plurality of multi-stage capacity compressors and the discontinuous output of each operating compressor capacity; and

generating control instructions corresponding to the determined configuration of the plurality of multi-stage capacity compressors to control the plurality of multi-stage capacity compressors to generate the predetermined output capacity for the refrigeration system .

12. The method of claim 11, wherein said step of determining a configuration of said plurality of multistage capacity compressors comprises selecting said plurality of multistage capacity compressors from a plurality of configurations of said plurality of multistage capacity compressors A configuration of capacity compressors, wherein each configuration of said plurality of configurations corresponds to a predetermined output capacity of said refrigeration system.

13. The method of claim 12, further comprising the step of storing said plurality of configurations of said plurality of multi-capacity compressors in a table.

14. The method of claim 13, wherein said step of selecting a configuration of said plurality of multicapacity compressors comprises selecting a configuration of said plurality of multicapacity compressors from said table.

15. The method of claim 12, wherein said plurality of evaporators includes each of said plurality of configurations for said plurality of multi-capacity compressors An evaporator configured.

16. The method of claim 15, wherein the step of selecting a configuration of said plurality of multi-capacity compressors includes selecting said An arrangement of multiple multi-capacity compressors.