CN115143655B

CN115143655B - Evaporation condensation magnetic suspension refrigerating unit

Info

Publication number: CN115143655B
Application number: CN202210697876.0A
Authority: CN
Inventors: 谢吉培; 陈见兴; 丛辉; 程振军; 徐晓明; 许琨
Original assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Current assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Priority date: 2022-06-20
Filing date: 2022-06-20
Publication date: 2023-05-23
Anticipated expiration: 2042-06-20
Also published as: CN115143655A

Abstract

The invention discloses an evaporation condensation magnetic suspension refrigerating unit, which comprises: a refrigerant circulation circuit; an evaporative condenser comprising a spray pump and a plurality of fans; the pressure compensation mechanism is connected between the liquid outlet end of the liquid storage device and the inlet end of the evaporator and comprises a valve body and a refrigerant pump which are connected in series; a control unit configured to, at a low loop temperature: when the suction pressure Ps of the compressor reaches the lower limit value of the second preset pressure, the valve body and the refrigerant pump are started, when the suction pressure Ps reaches the upper limit value of the first preset pressure, the refrigerant pump is closed, meanwhile, part of fans are started, then the compressor is started, after the starting of the compressor is completed, the valve body is closed, and the compressor is controlled to enter normal operation control; and when Ps reaches the upper limit value of the second preset pressure, at least a plurality of fans are started, then the compressor is started, and after the start of the compressor is completed, the compressor is controlled to enter normal operation control. The invention can ensure reliable starting at low ring temperature.

Description

Evaporation condensation magnetic suspension refrigerating unit

Technical Field

The invention relates to the technical field of air conditioners, in particular to an evaporation condensation magnetic suspension refrigerating unit.

Background

In the existing magnetic suspension refrigerating unit, the cooling mode is mostly water-cooled or air-cooled, the water-cooled energy efficiency is equivalent to that of the evaporative condensation magnetic suspension refrigerating unit, but the air-cooled cooling efficiency is lower than that of the evaporative cooling type, so that the evaporative condensation unit gradually becomes a good choice in places where the cooling tower cannot be arranged due to the fact that the relatively mature metropolitan area is limited by space, the installation problem of the cooling tower is solved, and the energy-saving requirement can be well met.

Under the conventional working condition, the magnetic suspension compressor in the magnetic suspension refrigerating unit is enough to meet the use requirement, but under the application of special engineering (such as the condition of annual refrigeration of process cooling and annual refrigeration requirement of a small data machine room), the magnetic suspension compressor is difficult to start under the working condition of low ambient temperature, such as the lowest evaporation temperature of the magnetic suspension compressor is minus 1 ℃, when the ambient temperature is minus 1 ℃, the air conditioning unit stands outdoors for a long time, the evaporation pressure of the air conditioning unit is basically close to the lowest value of the operation range of the compressor, when the unit is lower than minus 1 ℃, the evaporation pressure of the unit is not started, the alarm value is lower, and the alarm appears when the compressor is not started. Or the system pressure is slightly higher than the alarm pressure before the press is started, and the suction pressure is rapidly reduced to the alarm value at the moment because of less refrigerant at the low pressure side in the starting stage of the compressor, so that the starting failure is caused.

The natural cooling unit is divided into an antifreezing fluid type and a non-antifreezing fluid type according to the use condition of a user side water system, wherein the antifreezing fluid type refers to the filling of antifreezing fluid into the user side water system, the non-antifreezing fluid type refers to the filling of antifreezing fluid into a natural cooling coil of the unit, and the user water system is pure water.

However, in either form, in order to cope with low ring temperature conditions, the chilled water needs to be added with an anti-freezing solution, the proportion of the anti-freezing solution is determined according to the lowest ring temperature used locally, the system is easily frozen due to improper filling of the anti-freezing solution, and the system is easily corroded due to improper use of the anti-freezing solution.

Therefore, how to enable the evaporation condensation magnetic suspension refrigerating unit to realize reliable starting of the compressor at low ring temperature and avoid hidden trouble caused by adding antifreeze solution.

Disclosure of Invention

In order to solve the technical problems, the embodiment of the invention provides an evaporative condensing magnetic suspension refrigerating unit, which can ensure the reliable starting of a compressor at low ring temperature.

In order to achieve the aim of the invention, the invention is realized by adopting the following technical scheme:

in some embodiments of the present application, an evaporation-condensation magnetic suspension refrigerating unit is provided, which can start a valve body and a refrigerant pump when the suction pressure Ps of a compressor reaches a lower limit value of a second preset pressure through judgment of the suction pressure of the compressor at a low ambient temperature, and close the refrigerant pump when Ps reaches an upper limit value of a first preset pressure, simultaneously start a part of fans, then start the compressor, close the valve body after the start of the compressor is completed, and control the compressor to enter normal operation control.

The refrigerant can be circulated through the principle of pumping liquid at low pressure, the evaporation pressure of the system is increased, and then the refrigerant pump is closed, and the refrigerant enters the compressor refrigeration cycle to ensure the low-temperature and reliable starting of the compressor.

At low ring temperature, if the unit is started in the period of time after the machine unit is stopped, the refrigerant pump is judged to be unnecessary to be started through the suction pressure, and at the moment, the compressor can be directly started only by starting at least a plurality of fans.

That is, when Ps reaches the upper limit value of the second preset pressure, at least a plurality of fans are turned on, and then the compressor is started, and after the start of the compressor is completed, the compressor is controlled to enter normal operation control.

In some embodiments of the present application, for energy saving reasons, the number of fans to be turned on is determined according to the suction pressure determination, and when Ps reaches the upper limit value of the first preset pressure, all fans are turned on, and then the compressor is started, and after the start of the compressor is completed, the compressor is controlled to enter normal operation control.

And when Ps reaches the upper limit value of the second preset pressure and reaches the lower limit value of the first preset pressure, starting part of fans, starting the compressors, and controlling the compressors to enter normal operation control after the compressors are started.

In some embodiments of the present application, the compressor start mode of the evaporative condensing magnetic suspension refrigeration unit at high ambient temperature is also considered, and at high ambient temperature, the unit maintains higher evaporating pressure, in which case at least a plurality of fans are turned on and the pressure compensation mechanism is turned off, and whether to turn on the spray pump is determined by the suction pressure.

That is, when Ps reaches the upper limit value of the third preset pressure, the spray pump is turned on, and then the compressor is started, and after the start of the compressor is completed, the compressor is controlled to enter normal operation control.

And when Ps reaches the lower limit value of the third preset pressure, the spray pump is closed, then the compressor is started, and after the start of the compressor is completed, the compressor is controlled to enter normal operation control.

In some embodiments of the present application, because the unit maintains higher evaporation pressure under the action of the ambient temperature and the water temperature at the high ambient temperature, the fans are all turned on at this time, so that a better cooling effect can be obtained.

In some embodiments of the application, a compressor starting mode of the evaporative condensation magnetic suspension refrigerating unit at a transition ring temperature is also considered, and under the transition ring temperature, the pressure of the unit is influenced by the ring temperature and the water temperature, the pressure of the system can be higher than an alarm value, and a good cooling effect can be obtained only by starting a fan.

In some embodiments of the present application, for energy saving reasons, the number of fans to be turned on is determined according to the suction pressure determination, and when Ps reaches the upper limit value of the fourth preset pressure, all fans are turned on, and then the compressor is started, and after the start of the compressor is completed, the compressor is controlled to enter normal operation control.

And when Ps reaches the lower limit value of the fourth preset pressure, starting part of fans, starting the compressor, and controlling the compressor to enter normal operation control after the start of the compressor is completed.

In some embodiments of the present application, in order to be able to well utilize the wind force when turning on at least a plurality of fans, the turned on plurality of fans are dispersed to be turned on, thus forming a uniform wind field on top of the evaporative condenser.

In some embodiments of the present application, when a portion of fans are turned on, a uniform wind field is achieved by the arrangement positions of the plurality of fans and the positions of the turned-on fans.

That is, the plurality of fans of the evaporative condenser are arranged in a row at intervals;

the partial fans are started, and the method specifically comprises the following steps: adjacent fans in each row of fans are not started at the same time, and adjacent fans in each column of fans are not started at the same time.

The fans are arranged in a plurality of rows and columns at intervals, the interval marks of the fans in each row are odd and even, and the marks of the fans in the same column in the adjacent rows are different;

when a part of fans is turned on, a plurality of fans marked as odd numbers may be turned on, or a plurality of fans marked as even numbers may be turned on.

The evaporation condensation magnetic suspension refrigerating unit that this application provided has following advantage and beneficial effect:

(1) At low ring temperature, the evaporation and condensation pressure of the compressor is lower and is close to or lower than an alarm value, so that the compressor is difficult to start in refrigeration, the judgment of the suction pressure of the compressor is divided into two stages, wherein in the first stage, when the suction pressure reaches the lower limit value of the second preset pressure, a refrigerant pump and a valve body are started, the refrigerant is firstly circulated by utilizing the principle of pump liquid, then the suction pressure is increased along with the refrigerant circulation, when the suction pressure reaches the upper limit value of the first preset pressure, the refrigerant pump is closed, meanwhile, part of fans are started, then the compressor is started, after the compressor is started, the valve body is closed, and the compressor is controlled to enter normal operation control; the second stage, when the suction pressure reaches the upper limit value of the second preset pressure, starting at least a plurality of fans, and then starting the compressor to ensure that the compressor is reliably started at a low ring temperature;

(2) The refrigeration starting of the compressor at the low-ring temperature is realized, a natural cooling coil is not required to be designed, and the antifreezing solution is not required to be added to cope with the antifreezing under the low-ring temperature working condition.

Other features and advantages of the present invention will become apparent upon review of the detailed description of the invention in conjunction with the drawings.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a system for one embodiment of an evaporative condensing magnetic levitation refrigeration unit according to the present invention;

FIG. 2 is a flowchart of year-round refrigeration of an embodiment of the evaporative condensing magnetic levitation refrigeration unit provided by the invention;

FIG. 3 is a flow chart I of a refrigeration start-up at low ambient temperature for an embodiment of an evaporative condensing magnetic levitation refrigeration unit according to the present invention;

FIG. 4 is a second flowchart of a refrigeration start-up at low ambient temperature for an embodiment of the evaporative condensing magnetic levitation refrigeration unit according to the present invention;

FIG. 5 is a schematic diagram showing the arrangement of a plurality of fans in an embodiment of the evaporative condensing magnetic levitation refrigeration unit according to the present invention;

FIG. 6 is a second schematic diagram of a layout of a plurality of fans in an embodiment of the evaporative condensing magnetic levitation refrigeration unit according to the present invention;

FIG. 7 is a flowchart I of a refrigeration start-up at high ambient temperature for an embodiment of an evaporative condensing magnetic levitation refrigeration unit according to the present invention;

FIG. 8 is a second flow chart of the evaporative condensing magnetic levitation refrigeration unit according to the embodiment of the invention for refrigeration start at high ambient temperature;

FIG. 9 is a first flowchart of a refrigerating start-up at a transition ring temperature for an embodiment of an evaporative condensing magnetic levitation refrigeration unit according to the present invention;

fig. 10 is a second flowchart of a refrigeration start-up of the evaporation condensation magnetic suspension refrigeration unit according to the embodiment of the invention under the transition ring temperature.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments.

All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that the terms "mounted," "connected," and "coupled" are to be construed broadly, as well as, for example, fixedly coupled, detachably coupled, or integrally coupled, unless otherwise specifically indicated and defined. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art. In the description of the above embodiments, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

Operation principle of evaporation condensation magnetic suspension refrigerating unit

The refrigeration unit of the present application forms a refrigeration cycle by using a compressor 10, a condenser, a throttling element (e.g., an expansion valve) 70, an accumulator 30, and an evaporator 60.

The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and refrigerating an indoor space.

The compressor 10 in the application adopts a magnetic suspension compressor, and the magnetic suspension technology is utilized to reduce the non-mechanical friction of moving parts, so that the service life of the unit is greatly prolonged. The oil-free design of the system greatly reduces the parts of the system, improves the COP value of the system and greatly reduces the maintenance cost. The starting current is low (only 1A current) and has no impact on a power grid, a soft starter is not needed, the energy efficiency ratio advantage is more obvious especially in partial load, the method is suitable for various places with larger load change, and the operation cost can be saved by 50% compared with the traditional water chilling unit.

The condenser in the present application is efficiently cooled using an evaporative condenser 20.

The evaporative condenser 20 is a common heat exchange device, and is composed of a fan (for example, an axial flow fan), a condensing coil, heat exchange fins, a water pump, a water collector, a tank, and the like, and is a device that gradually cools the refrigerant in the condensing coil from a gaseous state to a liquid state by absorbing heat of the high-temperature gaseous refrigerant in the condensing coil when the shower water outside the condensing coil is partially evaporated.

Wherein a plurality of fans (not shown) are provided at the top of the housing of the evaporative condenser 20.

The evaporative condenser 20 takes water as a medium, and takes the condensation heat of the vapor refrigerant away by evaporation of the water, and is the most efficient condensation mode. The efficiency is more than 5 times of that of the air-cooled condenser, more than 1.5 times of that of the water-cooled condenser, the water consumption is less, about 1/3 of that of the water-cooled condenser, the spray pump is integrated in the evaporation condenser, the lift is 3-5 m, and the power consumption can be saved by more than 30%.

The working principle of the evaporation condensation magnetic suspension refrigerating unit is as follows:

the low-temperature low-pressure refrigerant enters the compressor 10, the compressor 10 compresses the refrigerant gas in a high-temperature high-pressure state, and the compressed refrigerant gas is discharged. The discharged refrigerant gas flows into the condensing coil of the evaporative condenser 20, and the high-temperature and high-pressure gaseous refrigerant exchanges heat with the shower water and air outside the condensing coil.

That is, the gaseous refrigerant is gradually condensed into liquid refrigerant from top to bottom after entering the condensing coil from the upper opening. The super strong wind power of the matched fan enables the spray water to completely and uniformly cover the surface of the condensing coil, and the water is used for greatly improving the heat exchange effect by wind force. The spray water with the temperature increased is partially changed into a gas state, a great amount of heat is taken away by wind potential by utilizing the vaporization latent heat of the water, water drops in the hot gas are caught by the high-efficiency dehydrator, and the water drops and the rest water which absorbs the heat are scattered into the heat exchange layer of the heat exchange plate, cooled by the flowing air, the temperature is reduced, enter the box body, and then continue to circulate through a spray pump (not shown).

The medium-temperature high-pressure liquid refrigerant from the evaporative condenser 20 enters the accumulator 30 and is throttled by the throttling element 70 to become low-temperature low-pressure liquid refrigerant, and flows into the evaporator 60.

The refrigerant in the evaporator 60 exchanges heat with the coolant (typically water), transfers the cold to the coolant, and the circulating coolant is cooled by a water pump and then fed into the room, which cools the room by the indoor coil.

At the same time, the evaporator 60 evaporates the low temperature low pressure liquid refrigerant into low temperature low pressure superheated refrigerant gas which is returned to the compressor 10, thereby completing a complete refrigerant refrigeration cycle.

Evaporation condensation magnetic suspension refrigerating unit

The evaporative condensing magnetic levitation refrigerator set (hereinafter referred to as refrigerator set) of the present application performs a refrigeration cycle by using a refrigerant circulation circuit formed of a compressor 10, an evaporative condenser 20, a liquid reservoir 30, a throttling element (e.g., an expansion valve) 70, and an evaporator 60.

Referring to fig. 1, the refrigeration unit further includes a pressure compensating mechanism and a control unit (not shown).

The pressure compensation mechanism is connected between the liquid outlet end of the liquid reservoir 30 and the inlet end of the evaporator 60, and comprises a valve body 50 and a refrigerant pump 40 which are connected in series.

The control unit is used for executing the refrigeration cycle of the refrigeration unit.

At high and transition ring temperatures, the refrigeration unit will maintain a relatively high vapor pressure under the influence of the ring temperature and the user side water temperature, and therefore, there will generally be no case where the suction pressure is already below the suction pressure alarm value when the compressor 10 is not started.

At low ambient temperature, if the refrigerating unit is not operated after long-time standing, the water temperature at the user side is higher, but the refrigerant is migrated to the low temperature side because the refrigerating unit is not operated for a long time, and the saturation temperature corresponding to the suction pressure is close to the ambient temperature, so the suction pressure is mainly affected by the ambient temperature at this time.

If the refrigerating unit directly starts the compressor 10 under the working condition, the refrigerant started by the compressor 10 is not circulated, and at this time, the refrigerating unit is easy to have low-pressure faults because of less refrigerant at the low-pressure side, so that the starting failure is caused.

The temperature values of the high ring temperature, the transition ring temperature and the low ring temperature as described above are sequentially reduced, and the specific division thereof can be freely defined.

For example, when the ring temperature is greater than the first preset temperature T1, the high ring temperature is considered to be a high ring temperature working condition; when the ring temperature is greater than the second preset temperature T2 and less than the first preset temperature T1, the transition ring temperature working condition is considered; and when the ring temperature is smaller than the second preset temperature T2, the working condition of the low ring temperature is considered.

Wherein the second preset temperature T2 is smaller than the first preset temperature T1.

Therefore, in order to realize the annual refrigeration requirement of the evaporative condensation magnetic suspension refrigerating unit, referring to fig. 2, the conditions of Gao Huanwen, transition ring temperature and low ring temperature are divided according to the ring temperature.

For the high-ring temperature working condition, for example, when the ring temperature is higher than the first preset temperature T1, the compressor is started at the high ring temperature.

For the transition ring temperature working condition, for example, when the ring temperature is greater than the second preset temperature T2 and less than the first preset temperature T11, the compressor is started at the transition ring temperature.

For the low-ring temperature working condition, for example, when the ring temperature is smaller than the second preset temperature T2, the compressor is started at the low ring temperature.

As follows, these three cases will be respectively explained.

As mentioned above, the problem of starting the compressor in the refrigeration unit at low ambient temperatures needs to be emphasized in order to achieve the annual refrigeration requirement of the refrigeration unit.

Compressor start-up at low ring temperatures

Operation control of the compressor 10 at low ring temperatures of the refrigeration unit is described with reference to fig. 1 and 3.

At low ring temperatures, i.e. ring temperatures less than the second preset temperature T2.

In order to solve the problem that the compressor 10 is difficult to start at the low-ring temperature as described above, the suction pressure Ps of the compressor 10 is considered, and the compressor 10 is reliably started at the low-ring temperature in combination with the suction pressure Ps.

Specifically, when the suction pressure Ps reaches the lower limit value of the second preset pressure, the valve body 50 and the refrigerant pump 40 are opened, and when Ps reaches the upper limit value of the first preset pressure, the refrigerant pump 40 is closed, and at the same time, part of the fan is opened, and then the compressor 10 is started, after the start of the compressor 10 is completed, the valve body 50 is closed, and the compressor 10 is controlled to enter the normal operation control.

When Ps reaches the upper limit value of the second preset pressure, at least a plurality of fans are started, then the compressor 10 is started, and after the start of the compressor 10 is completed, the compressor 10 is controlled to enter normal operation control.

As described above, the first preset pressure and the second preset pressure are set for the suction pressure Ps.

The first preset pressure and the second preset pressure may be a pressure interval or a pressure value at a point.

S31: the magnitudes of Ps and the second pressure P2 are determined, and if Ps is smaller than P2, the process proceeds to S32, otherwise, the process proceeds to S38.

As just an example, in fig. 3 above, when Ps reaches the lower limit value of the second preset pressure, that is, ps is equal to or smaller than P2, S32 is also performed.

Wherein P2 may refer to an inspiratory pressure alarm.

S32: the valve body 50 and the refrigerant pump 40 are opened.

As described above, at low ambient temperatures and with the refrigeration unit left inoperative for a long period of time, the compressor 10 in the refrigeration unit is susceptible to start-up failure.

If the ring temperature is very low, i.e., the ring temperature is lower than the third preset temperature T3 and the third preset temperature T3 is lower than the second preset temperature T2, the suction pressure Ps is already lower than the suction pressure alarm value without starting the compressor 10, resulting in that the compressor 10 cannot be started to operate at all.

In this condition, it is determined how to turn on the compressor 10 by the suction pressure Ps.

When Ps is smaller than (or equal to or smaller than) the second pressure P2, the valve body 50 and the refrigerant pump 40 are opened, the refrigerant is circulated by utilizing the principle of pumping liquid, the refrigerant absorbs heat of water at the user side in the evaporator 60 and is circularly evaporated, and the steam pressure of the system is increased, so that the suction pressure Ps of the compressor 10 is increased.

Then, whether the compressor 10 is started or not is determined based on the determination of the suction pressure Ps.

The principle of pumping needs to be described: under the low-temperature static condition of the refrigerating unit, the temperature corresponding to the saturation pressure in the system is similar to the ring temperature because the ring temperature is lower and the water temperature at the user side in the evaporator 60 is higher, and the refrigerant in the evaporator 60 gradually evaporates and migrates to the low-temperature device parts (namely the evaporative condenser 20 and the liquid storage device 30).

Before the compressor 10 is not operated, the refrigerant pump 40 and the valve body 50 are opened, the refrigerant is pumped into the evaporator 60 by the power of the refrigerant pump 40, the user side water pump in the evaporator 60 is always in circulation operation, and at the moment, the refrigerant absorbs the heat in water in the evaporator 60 to evaporate, so that the pressure of the whole refrigerant system is increased.

S33: the magnitudes of Ps and the first pressure P1 are determined, and if Ps is greater than P1, the process proceeds to S34, otherwise, the process returns to 33.

As just an example, in fig. 3 above, when Ps reaches the upper limit value of the first preset pressure, that is, ps is equal to or greater than P1, S34 is also performed.

Wherein the first pressure P1 is greater than the second pressure P2.

S34: the refrigerant pump 40 is turned off while turning on a part of the blower fan, and the process proceeds to S35.

As described in S32, the pump liquid principle is utilized to raise the pressure of the whole refrigerant system until the suction pressure Ps is greater than (or equal to) P1, the refrigerant pump 40 is turned off, and the partial fans are turned on at this time to obtain better cooling effect due to lower ring temperature.

S35: the compressor 10 is started and proceeds to S36.

As described in S34, when the suction pressure Ps reaches the upper limit value of the first preset pressure, it is ensured that the suction pressure of the compressor 10 can be greater than the suction pressure alarm value, and at this time, the compressor 10 is turned on and the compressor 10 can be started.

Meanwhile, the valve body 50 is always opened to increase the circulation quantity of the refrigerant, and the auxiliary compressor 10 is safely started under the low-ambient-temperature working condition.

S36: it is determined whether or not the start-up of the compressor 10 is completed, if so, the process proceeds to S37, otherwise, the process returns to S36.

The determination of whether the start-up of the compressor 10 is completed may be made by detecting a performance index of the compressor 10 (e.g., suction pressure or discharge superheat of the compressor 10, etc.).

For example, if the discharge superheat remains fluctuating within a small range for a period of time, this indicates that the compressor 10 has been started up to completion and enters a steady state operation.

S37: the valve body 50 is closed and the process proceeds to S39 ".

At this time, the compressor 10 has entered normal steady control, and therefore, the valve body 50 is closed.

S38: at least a plurality of fans are turned on, and the process proceeds to S39.

As just an example of fig. 3 above, when Ps reaches the upper limit value of the second preset pressure, that is, ps is greater than (or equal to) P2, it proceeds to S38.

Under the condition that the refrigerating unit meets the starting condition in a short time after stopping under the low-ring temperature working condition, the refrigerating unit is not completely cooled due to short stopping time, the refrigerant at the low-pressure side is not completely evaporated and migrated, and the higher evaporating pressure and the higher suction pressure are still kept in the system.

When the suction pressure Ps reaches the upper limit value of the second preset pressure, it indicates that the condition for turning on the refrigerant pump 40 is not satisfied.

At this time, because the ring temperature is lower, the refrigerating unit starts a plurality of at least fans, can obtain better cooling effect.

Referring to fig. 4, a flowchart is shown in which the refrigeration unit determines the number of fan starts based on the suction pressure Ps when Ps reaches the upper limit value of the second preset pressure.

When Ps is greater than P2, the process proceeds to S381.

S381: the magnitudes of Ps and the first pressure P1 are determined, and if Ps is greater than P1, the process proceeds to S382, otherwise, the process proceeds to S383.

As just an example, in fig. 4, when Ps reaches the upper limit value of the first preset pressure, that is, ps is equal to or greater than P1, S382 is also performed.

S382: all fans are started and proceed to S39.

At this time, the refrigerating unit has higher evaporating pressure, but because the ring temperature is lower, all fans are started, and a better cooling effect is obtained.

S383: part of the fans are started and proceeds to S39.

At this time, the refrigerating unit has a not too high evaporation pressure, ps reaches an upper limit value of the second preset pressure and reaches a lower limit value of the first preset pressure, that is, ps is greater than or equal to P2 and Ps is less than or equal to P1.

However, at this time, the ring temperature is low, so that part of fans are started to obtain a good cooling effect.

The fans can be arranged in a plurality of rows and columns at intervals, and when part of the fans are started, the fans are started in a scattered mode.

The uniform wind field can be ensured by the dispersed opening, so that the spray water completely and uniformly covers the surface of the condensing coil, and the heat exchange effect of the evaporative condenser 20 is greatly improved by the wind force of the water.

The plurality of fans may be arranged in a row and spaced apart.

And when part of fans are started, adjacent fans in each row of fans are not started at the same time, so that the scattered starting of the part of fans is ensured.

Referring to fig. 5, a plurality of fans are arranged in two rows and five columns at intervals, which are respectively denoted as fan a11, fan a12, fan a13, fan a14, fan a15, fan a21, fan a22, fan a23, fan a24 and fan a25, and fan a11, fan a14, fan a22 and fan a25 can be turned on.

Referring to fig. 6, a plurality of fans are arranged in a plurality of rows and columns at intervals, with the fan intervals of each row being marked as odd and even, and the fans of the same column of adjacent rows being marked differently.

S39: the compressor 10 is started and proceeds to S39'.

As described in S38, when the suction pressure Ps reaches the upper limit value of the second preset pressure, it is ensured that the suction pressure of the compressor 10 can be greater than the suction pressure alarm value, and at this time, the compressor 10 is turned on and the compressor 10 can be started.

S39': it is judged whether or not the start-up of the compressor 10 is completed, if yes, it goes to S39 ", otherwise, it goes back to S39'.

S39'': the compressor 10 enters normal operation control.

After the start of the compressor 10 is completed, the branch where the pressure compensation mechanism is located is cut off, and the refrigerant circulation circuit starts to perform normal refrigeration.

The normal operation control herein refers to the operation control of the compressor 10 when the refrigeration unit is operating normally.

In order to ensure the annual refrigeration reliability of the evaporative condensation magnetic suspension refrigerating unit, the application also considers the conditions under the high-ring temperature working condition and the transitional ring temperature working condition.

Gao Huanwen compressor start-up

With reference to fig. 1, 7 and 8, a flow chart of the start-up of the compressor 10 at high ring temperatures is shown.

Under the high-ambient temperature condition, the refrigerating unit keeps higher evaporation pressure and suction pressure Ps under the action of ambient temperature and user side water temperature, so that a pressure compensation mechanism is not required to be started under the condition, namely, the refrigerant pump 40 and the valve body 50 are closed.

At this time, at least a plurality of fans are started to obtain a better cooling effect.

However, since the ring temperature is high in this condition, in order to avoid that the suction pressure Ps does not increase too fast after the start-up of the compressor 10 is completed, it is determined whether to turn on the shower pump by the suction pressure Ps.

S51: the magnitudes of Ps and the third pressure P3 are determined, and if Ps is greater than P3, the process proceeds to S52, otherwise, the process proceeds to S53.

As just an example, in fig. 5 above, when Ps reaches the upper limit value of the third preset pressure, that is, ps is equal to or greater than P3, S52 is also performed.

The third pressure P3 may be equal to or greater than the first pressure P1.

S52: the shower pump is turned on and proceeds to S54.

The suction pressure Ps is larger, and the cooling effect is enhanced by starting the spray pump, so that the pressure of the refrigerating unit is ensured not to be increased too fast after the starting.

S53: the shower pump is turned off and the process proceeds to S54.

Here, turning off the spray pump means (1) if the spray pump was previously turned on, the spray pump should be turned off at this time; (2) If the spray pump was previously turned off, the spray pump should remain turned off.

S54: the compressor 10 is started and proceeds to S55.

S55: it is determined whether or not the start of the compressor 10 is completed, if so, the process proceeds to S56, otherwise, the process returns to S55.

S56: the compressor 10 enters normal operation control.

Referring to fig. 8, at high ambient temperature, the refrigerator set maintains higher evaporating pressure and suction pressure under the combined action of ambient temperature and user side water temperature, so that at least a plurality of fans, particularly all fans, are turned on at this time to obtain better cooling effect.

Compressor start-up at transition ring temperature

Referring to fig. 1, 9 and 10, a flow chart of a start-up of the compressor 10 at transition ring temperature is shown.

Under the transitional ring temperature working condition, the air suction pressure Ps of the refrigerating unit is higher than the air suction pressure alarm value under the action of the ring temperature and the water temperature of the user side. Therefore, under such conditions, there is no need to open the pressure compensating mechanism, i.e., both the refrigerant pump 40 and the valve body 50 are closed.

Because the spray pump is started to strengthen the cooling effect, the refrigerating unit is difficult to establish the pressure ratio or the pressure difference in a short time, so that the refrigerant circulation is slow, and the refrigerant quantity at the low pressure side is possibly insufficient, and therefore, the spray pump is closed under the working condition.

Under the working condition, because the ring temperature is low, a better cooling effect can be obtained only by starting a plurality of fans.

After that, the compressor 10 is started, and after the start-up of the compressor 10 is completed, normal operation control is entered.

Referring to fig. 10, the number of fan openings can be determined by the suction pressure Ps.

As described above, under the transient ring temperature condition, the pressure compensation mechanism is not required to be opened, i.e., both the refrigerant pump 40 and the valve body 50 are closed.

S101: the magnitudes of Ps and the fourth pressure P4 are determined, and if Ps is greater than P4, the process proceeds to S102, otherwise, the process proceeds to S103.

As just an example, in fig. 10, when Ps reaches the upper limit value of the fourth preset pressure, that is, ps is equal to or greater than P4, the process proceeds to S102.

The third pressure P4 may be equal to or greater than the first pressure P1.

S102: all fans are turned on and proceed to S104.

S103: part of the fans are started and proceeds to S104.

At this time, ps reaches the lower limit value of the fourth preset pressure, the refrigerating unit has a lower evaporation pressure, and when the suction pressure Ps is low, a part of fans are turned on to quickly establish a pressure ratio or a pressure difference to promote refrigerant circulation.

The plurality of fans can be arranged in rows and intervals; the partial fans are started, adjacent fans in each row of fans can be started at different times, and the scattered starting of the partial fans is ensured.

Still referring to fig. 5, a plurality of fans are arranged in two rows and five columns at intervals, which are respectively denoted as fan a11, fan a12, fan a13, fan a14, fan a15, fan a21, fan a22, fan a23, fan a24 and fan a25, and fan a11, fan a14, fan a22 and fan a25 can be turned on.

Still referring to FIG. 6, the plurality of fans are arranged in rows and columns with the fan spacing of each row being marked as odd and even and the fans of the same column of adjacent rows being marked differently.

S104: the compressor is started and proceeds to S105.

S105: it is determined whether or not the start of the compressor 10 is completed, if so, the process proceeds to S106, otherwise, the process returns to S105.

S106: the compressor 10 enters normal operation control.

The refrigerating unit that this application provided can carry out state control to fan, spray pump and pressure compensating mechanism through the judgement of ring temperature and suction pressure, ensures that compressor 10 is fault-free reliably starts under different ring temperature operating mode, realizes refrigerating unit refrigeration all the year round.

The refrigerating unit can be cooled by adopting the evaporative condenser 20, so that the problem that a cooling tower cannot be installed due to position reasons can be solved, and the problem that the energy efficiency of a fan unit is low can be solved.

The utility model provides a refrigerating unit utilizes the principle of pump liquid to start the compressor 10 refrigeration under low ring temperature operating mode, and the system need not to design natural cooling coil, and need not to increase antifreeze solution and deal with low temperature operating mode and prevent frostbite, guarantees that refrigerating unit can be under low ring temperature operating mode, and compressor 10 can be safe trouble-free start, realizes the purpose of compressor 10 refrigeration operation under the low ring temperature operating mode.

The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be apparent to one skilled in the art that modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some of the technical features thereof; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims

1. An evaporative condensing magnetic levitation refrigeration unit, comprising:

a refrigerant circulation loop for circulating the refrigerant in a loop formed by the compressor, the evaporative condenser, the liquid storage device, the throttling element and the evaporator;

an evaporative condenser comprising a spray pump and a plurality of fans;

the pressure compensation mechanism is connected between the liquid outlet end of the liquid storage device and the inlet end of the evaporator and comprises a valve body and a refrigerant pump which are connected in series;

a control unit configured to, at a low loop temperature:

when the suction pressure Ps of the compressor reaches the lower limit value of the second preset pressure, the valve body and the refrigerant pump are started, when the suction pressure Ps reaches the upper limit value of the first preset pressure, the refrigerant pump is closed, meanwhile, part of fans are started, then the compressor is started, after the starting of the compressor is completed, the valve body is closed, and the compressor is controlled to enter normal operation control;

when Ps reaches the upper limit value of the second preset pressure, at least a plurality of fans are started, then the compressor is started, and after the start of the compressor is completed, the compressor is controlled to enter normal operation control;

wherein the second preset pressure is less than the first preset pressure.

2. An evaporative condensing magnetic levitation refrigeration unit according to claim 1,

when Ps reaches the upper limit value of the first preset pressure, starting all fans, starting the compressor, and controlling the compressor to enter normal operation control after the start of the compressor is completed;

3. An evaporative condensing magnetic levitation refrigeration unit according to claim 1, wherein the control unit is configured to:

closing the valve body and the refrigerant pump, and opening at least a plurality of fans;

when Ps reaches the upper limit value of the third preset pressure, starting the spray pump, starting the compressor, and controlling the compressor to enter normal operation control after the start of the compressor is completed;

4. An evaporative condensing magnetic levitation refrigeration unit according to claim 3, wherein turning on at least a plurality of fans is configured to turn on all fans.

5. An evaporative condensing magnetic levitation refrigeration unit according to claim 3, wherein the control unit is configured to:

closing a valve body, a refrigerant pump and a spray pump, starting at least a plurality of fans, starting a compressor, and controlling the compressor to enter normal operation control after the compressor is started;

wherein the transition ring temperature is between the ring temperature and the high ring temperature.

6. An evaporative condensing magnetic levitation refrigeration unit according to claim 5,

when Ps reaches the upper limit value of the fourth preset pressure, starting all fans, and then starting the compressor;

when Ps reaches the lower limit value of the fourth preset pressure, starting part of fans, and then starting the compressor;

and after the start of the compressor is completed, controlling the compressor to enter normal operation control.

7. An evaporative condensing magnetic levitation refrigeration unit according to any of claims 1-6, wherein at least a plurality of fans turned on are dispersed on.

8. An evaporative condensing magnetic levitation refrigeration unit as set forth in claim 7 wherein the plurality of fans of the evaporative condenser are arranged in rows and spaces; the partial fans are started, and the method specifically comprises the following steps:

adjacent fans in each row of fans are not started at the same time, and adjacent fans in each column of fans are not started at the same time.

9. The evaporative condensing magnetic levitation refrigeration unit of claim 8, wherein the plurality of fans are arranged in a plurality of rows and columns at intervals, and wherein the fan intervals of each row are marked as odd and even, and wherein the marks of the fans of the same column in adjacent rows are different;