EP3821185A1 - Refrigerant vapour quality measurement for optimized evaporator control and liquid distribution - Google Patents
Refrigerant vapour quality measurement for optimized evaporator control and liquid distributionInfo
- Publication number
- EP3821185A1 EP3821185A1 EP19833246.2A EP19833246A EP3821185A1 EP 3821185 A1 EP3821185 A1 EP 3821185A1 EP 19833246 A EP19833246 A EP 19833246A EP 3821185 A1 EP3821185 A1 EP 3821185A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- evaporator
- gas
- refrigerant
- control system
- evaporators
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000003507 refrigerant Substances 0.000 title claims abstract description 80
- 239000007788 liquid Substances 0.000 title claims abstract description 68
- 238000005259 measurement Methods 0.000 title claims description 32
- 238000001816 cooling Methods 0.000 claims abstract description 24
- 239000011800 void material Substances 0.000 claims description 11
- 230000001276 controlling effect Effects 0.000 claims description 9
- 238000002604 ultrasonography Methods 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 7
- 230000005514 two-phase flow Effects 0.000 claims description 6
- 238000009530 blood pressure measurement Methods 0.000 claims description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims 2
- 229910021529 ammonia Inorganic materials 0.000 claims 1
- 238000005057 refrigeration Methods 0.000 description 10
- 238000001704 evaporation Methods 0.000 description 8
- 230000008020 evaporation Effects 0.000 description 8
- 239000002245 particle Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 239000003570 air Substances 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 230000001965 increasing effect Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000006096 absorbing agent Substances 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 241001481828 Glyptocephalus cynoglossus Species 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 229940000425 combination drug Drugs 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 235000019628 coolness Nutrition 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 229940086255 perform Drugs 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B5/00—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity
- F25B5/02—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity arranged in parallel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B21/00—Machines, plants or systems, using electric or magnetic effects
- F25B21/02—Machines, plants or systems, using electric or magnetic effects using Peltier effect; using Nernst-Ettinghausen effect
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B45/00—Arrangements for charging or discharging refrigerant
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/005—Arrangement or mounting of control or safety devices of safety devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/23—Separators
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2500/00—Problems to be solved
- F25B2500/28—Means for preventing liquid refrigerant entering into the compressor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
- F25B2600/2513—Expansion valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/13—Mass flow of refrigerants
- F25B2700/135—Mass flow of refrigerants through the evaporator
- F25B2700/1353—Mass flow of refrigerants through the evaporator at the outlet
Definitions
- the present invention relates to an evaporator control system adapted for control of one or more evaporators of a cooling system, which cooling system comprises at least one compressor for generating high pressure refrigerant gas, which high pressure re- frigerant gas is sent through condensing means for cooling and condensing into liquid refrigerant, which liquid refrigerant is sent through a pressure reduction means such as expansion valves towards one or more evaporators, from which evaporators low pres- sure refrigerant suction gas is sent through a suction pipe towards the compressor.
- Control of evaporators is performed by a temperature feedback from the evaporator’s outlet to control of expansion valves.
- DX evaporator control is normal calculated as superheat by measuring temperature and pressure as a feedback from the outlet of the evaporator to control of an expansion valve.
- Overfeed systems are either pump or thermosiphon based where the refrigerant feed rate is forced by a pump or gravity driven circulation.
- US2013291568A discloses a system or a method for performing capacitive sensing of humidity/liquid, primarily in conductive or non-conductive liquid/gas mixtures, hav ing a control unit and at least first and second sensor electrodes, the capacity between the first and the second electrodes being measured.
- At least one of the sensor electrodes is formed as a tube, which is placed in the liquid/gas mixture. Based on the capacitive measurements, a calculation of at least one dataset for control of a second system is performed.
- the tube can be more or less filled up with liquid or gas and the electric capacity measured in pF will change as it depends on the content around or inside the tube, and if a dry gas is dr ⁇ ' there will be one value of capacity and in a situation where the gas is being replaced by liquid, the capacity value will change rapidly.
- the evaporator control system is adapted to performs con trol of refrigerant liquid flow into evaporators based on input from one or more vapour gas quality sensors placed in the evaporator outlet or in the suction pipe, which vapour gas quality sensor measures the content of liquid refrigerant in the suction gas, which system controls the inlet of refrigerant to the evaporator based on the vapour gas quality measured in the suction pipe or at the evaporator outlet.
- the system comprises a gas flow sensor, which gas flow sensor is adapted to measuring the gas flow in the evaporator outlet.
- gas flow sensor is adapted to measuring the gas flow in the evaporator outlet.
- the gas flow can be measured by a plurality of flow sensors, such as mass flow sensors, ultra sound sensors, vortex sensors or thermal sensors.
- the thermal sensors are preferred, because it is easy to place a small heating element and a thermo sensor with a small distance in the outlet from an evaporator section. By measuring the flow in each evaporator section the system can calculate the effective- ness of an evaporator.
- the system can open the modulated expansion valve to increase the flow in the evapo- rator section. If no flow is indicated in an evaporator section this can indicate that no evaporation takes place in that section of an evaporator. This can indicate ice at the evaporator section and stop of the modulated expansion valve, and if more evaporator sections have reduced flow de-icing can be necessary.
- the system can be adapted to per form simultaneous capacitive measurement of void fraction of the liquid flow rate.
- capacitive measurement with simultaneous measurement of temperature ensures greater measuring accuracy simply because it is possible here to perform a temperature compensation.
- the sensor is based on capacitive measure- ment principles in which two measuring electrode/conductors measure the capacity.
- the ratio between vapour and liquid amount in a two-phase flow be meas- ured instantly for example without delay as a volume based void fraction measure- ment.
- Capacitive void fraction measurement with simultaneous measurement of the liquid flow rate ensures high accuracy and direct flow measurement measured in me- ters per second
- the system can be adapted to use ultrasound measurement to measure the velocity of the liquid in one or more tubes.
- ultrasound measurement can be achieved for example by use of an ultrasound transducer to measure the velocity of the liquid in the tube simply because the ultrasound is based on the dobler principle.
- the system can be adapted to per form calculation of mass flow based on the measured void fraction, the actual temper ature, liquid flow and gravity of the refrigerant.
- the system can be adapted to per form calculation of mass flow based on the measured void fraction, the actual temper ature, liquid flow and gravity of the refrigerant.
- the mass flow can be measured in a tube with as two phase flow measured in kg/m3.
- Mass flow measurement is highly effective if capacitive void fraction measurement with simultaneous measurement of temperature and liquid flow can ensure high meas- urement accuracy measured instantly without delay.
- This can be used on very de- manding applications e.g. for measuring the circulation rate on evaporators and calcu- lating the evaporator performance/output in kW.
- an evaporator which is divided in a number of sections to perform measurement of mass flow from each of these sections.
- a further preferred embodiment for the invention can control of one or more expan sion valves control the inlet of refrigerant to the evaporators based on a signal gener- ated by the gas quality sensors.
- the thermo valve or superheat control with the vapor quality sensor, which instead of measuring superheat is measuring quality of the suction gas, it is possible to control the expansion valve in a much more effective way than based on a temperature and pressure measurement.
- the quality of the suction gas it is possible to adjust the quality of the suction gas to a level where evaporation is performed totally, but without achieving superheat condi- tions. Hereby is achieved a controlled higher degree of filling of an evaporator during operation.
- the system can be adapted to per- form control of direct expansion evaporators based on the signal from the gas quality sensor, which measure the content of liquid refrigerant in the suction gas leaving the direct expansion evaporator.
- the gas quality sensors enable operation of a refrigeration system as a DX-system (direct expansion).
- the advantage of the sensor principle is a low refrigerant charge in the system compared to overfeed/flooded evaporators. A reduction in refrigerant charge by factor up to 1,000 is possible in the evaporators compared to liquid over feed or gravity fluid feed may be anticipated.
- By controlling the quality of the suction gas it is possible also by dry expansion evaporators to achieve a much higher yield of the evaporator, simply be- cause an optimal filling with refrigerant is possible and thereby much more effective heat transfer is performed.
- one or more refrigerant pumps perform supply of liquid refrigerant to one or more evaporators based on signal from gas quality sensors.
- the supply from a receiver to a plurality of evaporators is performed by a number of pumps.
- the outlet from these evaporators is non-evaporated liquid sent back to the separator, where a separation is performed and where evaporated gas is returned to compressor means.
- the pumps are under control, so not only liquid refrigerant flow to the evaporators, but that the flow is reduced in a way where effective evaporation takes place.
- these evaporators can operate highly effective by control of pumps or maybe by control of different valves controlling the flow into the evaporators.
- the system can be adapted to per form control of one or more flooded evaporators based on the signal from the gas quality sensor, which measures the content of liquid refrigerant in the suction gas leaving the flooded evaporators.
- flooded evaporators can operate much more effective simply because it is possible to adjust the driving head from the receiving tank in a way where the liquid level can be adjusted in accordance with the demand for cooling. If more cooling is needed it is simply to fill up the driv- ing head so that the pumping is increased. In a situation where for example the cooling demand is decreasing, no more liquid refrigerant is added to the receiving tank and because there is a continuous evaporation, the driving head will be reduced after a short while.
- the quality sensor can perform electronic capacity calculation of the electric capacity between a first and a second sensor electrode, which first and second electrodes are placed in the suction pipe at the outlet of the evaporator.
- the electric capacity between the two sensors can indicate droplets of liquid particles when they are passing between the plates/conductors.
- an electric system it is relatively easy to measure the capacity and in that way it is possible also to indicate the quality of the gas.
- the cooling system comprises a plurality of independent evaporators, which evaporators are controlled by independent gas quality sensors controlling expansions valves that control the liquid inlet to the evaporators.
- the invention can be disclosed as a method for operating a cooling system by an evaporator control system as disclosed in one of the claims 1-13 in the following steps of operation: a: perform measurement of the electric capacity in pF between electrodes in the quali ty sensor, b: let the evaporator control system calculate the quality of the suction gas based on the measured capacity, c: let the evaporator control system based on the quality measure the flow pattern in the evaporator outlet, d: let the evaporator control system decide if the suction gas is dry or wet, e: let the evaporator control system perform control of the liquid refrigerant inlet to the evaporator.
- b let the evaporator control system calculate the quality of the suction gas based on the measured capacity
- c let the evaporator control system based on the quality measure the flow pattern in the evaporator outlet
- the invention can be disclosed as a method for operating an evaporator control system in the following step: a: perform simultaneous measurement of void fraction of the liquid flow rate of the refrigerant, b: perform measurement of temperature of the refrigerant, c: perform pressure measurement of the refrigerant, d: perform measurement of vapour cross section and total cross section, e: calculate the mass flow in two phase flow of refrigerant.
- the technology of measuring flow velocity by ultrasound transducers is well-known. In this way it will be possible by each single sections of an evaporator to indicate the mass flow through this section. In this way any malfunction in an evaporator section will be detected. Also the capacity of the evaporator can be calculated in quite another way simply because it is able to supply a customer with mass flow data of the total mass flow through an evaporator.
- the evaporator control system can be used as riser control. In systems where for example the evaporator is placed far below a compressor, a riser is necessary in order to move the evaporated refrigerant from the refrigerator upwards, maybe several meters into the inlet of the compressor.
- this invention can be used for defrost control on heat-pumps air to water types, where the energy absorber is an air-cooler placed outdoor.
- this new method where single or an actively distributing valve are used, which is able to feed parallel evapora tor circuits individually. With this valve single evaporator circuits could be regularly shut off. While no refrigerant is evaporated in a closed circuit, the coil surface temper ature increases and the flow of the ambient air is sufficient to defrost this part of the evaporator.
- Experimental results show that under standard frost conditions the evapo rator can be kept frost-free and even under severe conditions most of the highly ineffi cient system defrosts can be avoided. Thereby system efficiency is increased signifi cantly. Description of the Drawing
- Fig. 1 shows a possible embodiment for a refrigeration system.
- Fig. 2 shows a multi electronic flow distributor expansion valve manifold.
- Fig. 3 shows a plurality of suction tubes connected to the evaporator’s outlet.
- Fig. 4 shows the measuring range DX and OVC.
- Fig. 5 shows part of a refrigeration system comprising an evaporator.
- Fig. 6 shows an outlet from an evaporator with a flow sensor and a vapour quality sensor.
- Fig. 7 shows same embodiment as in fig. 6, but here connected to an evaporator.
- Fig. 1 shows a possible embodiment for a refrigeration system 6, which comprises an evaporator control system 2.
- This evaporator control system 2 is connected to an evaporator 4.
- a compressor 8 is generating high pressure refrigeration gas in a line 10, which is connected to an oil separator 32. From here pressure line continues up to a condenser 12, where liquid refrigerant is now flowing in a tube 14 to a receiver 34. From here the refrigerant is sent to a separator 40 and further through line 42 to the evaporator 4.
- the evaporator 4 comprises quality sensors 26 and modulated expansion valves 38 to control the flow into the evaporator. Further is indicated several vapour quality sensors 26 in the suction outlet of the compressor 8.
- the compressor 8 will generate high pressure gas in the line 10, which is supplied to the oil separator 32, where oil particles are separated from the pressure gas.
- the pressure gas is hereafter sent further in tubing into the condenser 12, where for example air is performing a cooling of the gas, so a condensation takes place and in the tube 14 liquid high pressure refrigerant is sent towards the receiver 34.
- the high pressure liquid refrigerant is sent to a separator 40, which separa- tor operates as a subcooler, where relative cold suction gas is being preheated and the liquid high pressure refrigerant is being cooled to a lower temperature into the line 42.
- the line 42 is connected to the multi electronic liquid flow distribution expansion valve manifold 38.
- a plurality of modulated valves will be activated in order to open for liquid refrigerant to enter more evaporators sections.
- Each of these evapora- tor sections are then controlled by quality sensors 26, which are able to measure the quality of the suction gas and stop the modulated valve, if the gas is detected as wet.
- the suction gas which is leaving the evaporator sections is sent through the tubing 54 into a suction valve 36. From here the suction gas is passing the separator, where the gas and liquid is separated. Further in line 22 the suction gas is flowing to- wards the compressor 8, where one further quality sensor 26 is indicating if there should be liquid refrigerant on its way to the compressor and if liquid is detected; the sensors 26 will stop the compressor immediately.
- liquid refrig erant is entering the piston compressor which would probably destroy the compressor immediately.
- Fig. 2 shows a multi electronic flow distributor expansion valve manifold 38.
- a tube for high pressure liquid refrigerant 42 is arranged with a plurality of connections to the modulated valves 44. These modulated valves are further connected to the individual tubes for liquid supply 46, which modulated valves 44 are connected by a electronic data bus 48. This data bus 48 is by a bus interface 50 connected to the modulated valves 44.
- each of the modulated expansion valves 44 will be controlled by signals that are sent through the data bus 48.
- the valves 44 are as such operating as controllable expansion valves. Other kinds of modulations are also possible. In one situation it is of course possible to keep one of the valves totally open and in another situation totally closed. In a situation where a plurality of evaporator sections are op- erating, which number can be much higher than indicated at this figure, these evapora- tor sections are controlled independently of each other, because the inlet to the evapo- rator section is controlled by the modulated expansion valves.
- Fig. 3 shows a plurality of suction tubes 52 connected to the evaporator’s outlet.
- the tubes 52 are connected to the suction tube 54, which is connected directly or indirectly to a suction manifold which are connected to the suction line going to the compressor.
- a plurality of gas quality sensors 26 which are electrical connected to an electrical bus interface 58. This bus interface 58 is further connected to a data bus 56.
- the gas quality sensors will indicate if there are liquid particles in the suc- tion gas leaving the evaporator section.
- the gas quality sensors 26 will continuously measure the gas quality in the tubes 54 coming from the evaporator sections. As long as the gasses are dry it is possible for the modulated expansion valve 44 operating in that same evaporator to continue operation, but in a situation where one of the evapo- rator sections seems to be more or less filled up with liquid refrigerant and droplets of refrigerant is detected by the quality sensors 26, there is no need to continue filling more liquid refrigerant into an evaporator section, which is already operating with its maximum cooling effect. Therefore, also from a view of energy consumption it is highly effective to control the inlet of each evaporator section in accordance with the quality of the gas that is leaving the evaporator section.
- Fig. 4 shows the measuring range DX and OVC shown in an H-log P diagram. From the figure it is clear that using the DX technology the superheat can be reduced and hereby the total energy consumption of a refrigeration system is reduced because su- perheat is only necessary in order to protect a compressor. Further the suction pressure will increase and hereby reduce the power consumption of the compressor. The extra energy that is occupied by the superheat of the refrigerant has together with the energy that is achieved during the compression also energy that has to be removed in the con- densator. The lower temperature from the compressor will lead to a more efficiency condensation.
- Fig. 5 shows a part of a refrigeration system comprising an evaporator 4 (here men tioned as a freezer).
- the inlet to that evaporator 4 is controlled by an electronic expan sion valve 16.
- a suction pipe 22 and an evaporator outlet 28 is connected to a riser 62 up to a quality sensor 26.
- a pump 30 is pumping refrigerant through the expansion valve 16.
- the pump 30 is controlled by a pump control 60, which pump control 60 is receiving an input from the quality sensor 26.
- the pump will receive refrigerant from a pump-separator or condenser and increase the pressure towards the liquid control valve 16.
- the evaporator 4 which could be a freezer because of the pressure in the evaporated refrigerant is able to flow through the riser 62 up to the quality sensor 26 and further into the suction pipe 22.
- the traditional way of controlling a DX evaporator is to measure the suction pressure and the temperature inside or outside the suction tube of an evaporator and based on that temperature to control the inlet to the evaporator.
- a regulation where a superheating of the gas leaving the evaporator is performed.
- regulation is performed so that the temper ature is 10 degrees or maybe even higher in order to be sure that all the refrigerant is evaporated.
- Fig. 6 shows a possible embodiment of an evaporator outlet tube 52, which is con nected to a gas flow sensor 64 and further connected to a gas quality sensor 26.
- a tube 54 which is a suction tube leading towards a compressor.
- the gas flow sensor 64 could be a thermal based flow sensor operating in that way that a small heating element is heating one temperature sensor in combination with another temperature sensor measuring the temperature of the gas. At low gas flow is the temperature difference high, when the gas flow in crease there is a higher degree of temperature difference witch indicates a lower gas flow. In that way by calibration a relative good indication for the flow velocity can be achieved.
- Fig. 7 shows same features as in fig. 6, but now an evaporator 4 and an expansion valve 16 are also indicated.
- the quality sensors 26 and the gas flow sensors 64 are together measuring the gas quality leaving the evaporator. Signals are sent to a central control system. This control system also controls the expansion valve 16. By controlling the quality of the gas leaving the evaporator 4, it is possible to totally fill the evaporator with liquid boiling refrigerant. As long as there is a flow as indicated by the gas flow sensor 64, the control system can open the expansion valve and add more refrigerant into the evaporator. As soon as the quality sensor indicates liquid particles in the gas leaving the evaporator, a command for reducing the inlet by partly or totally closing the ex- pansion valve would be given from the control system.
- the gas flow sensor indicates that there is no flow in the line 52. In that situation it could be necessary also to send a command to the expansion valve 16 to let that valve close.
- a system as disclosed it is possible to perform a highly effective control of evapo- rators or evaporator sections. Especially by controlling each section of an evaporator it is possible to totally fill up that evaporator with boiling refrigerant, because the quality and the flow is under control, it is possible to increase the temperature flowing in the suction line 54 towards the compressor. Therefore, the system as disclosed is increas- ing the effectivity of a cooling or heat-pump system.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Air Conditioning Control Device (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DKPA201870481 | 2018-07-11 | ||
PCT/DK2019/050223 WO2020011327A1 (en) | 2018-07-11 | 2019-07-08 | Refrigerant vapour quality measurement for optimized evaporator control and liquid distribution |
Publications (2)
Publication Number | Publication Date |
---|---|
EP3821185A1 true EP3821185A1 (en) | 2021-05-19 |
EP3821185A4 EP3821185A4 (en) | 2022-04-06 |
Family
ID=69469332
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19833246.2A Pending EP3821185A4 (en) | 2018-07-11 | 2019-07-08 | Refrigerant vapour quality measurement for optimized evaporator control and liquid distribution |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP3821185A4 (en) |
DK (1) | DK201970446A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP4269909A1 (en) * | 2022-04-26 | 2023-11-01 | IGLOO Spolka z ograniczona odpowiedzialnoscia | System for distributing refrigerant to a heat exchanger and method for operation thereof |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3257824A (en) * | 1964-12-16 | 1966-06-28 | Itt | Integral lubricant return riser for refrigeration systems |
US7775057B2 (en) * | 2007-06-15 | 2010-08-17 | Trane International Inc. | Operational limit to avoid liquid refrigerant carryover |
WO2012062329A1 (en) * | 2010-11-12 | 2012-05-18 | Hb Products A/S | System or method for measuring the phase of refrigerant in a cooling system |
US10047990B2 (en) * | 2013-03-26 | 2018-08-14 | Aaim Controls, Inc. | Refrigeration circuit control system |
US20160120059A1 (en) * | 2014-10-27 | 2016-04-28 | Ebullient, Llc | Two-phase cooling system |
-
2019
- 2019-07-08 EP EP19833246.2A patent/EP3821185A4/en active Pending
- 2019-07-08 DK DKPA201970446A patent/DK201970446A1/en not_active Application Discontinuation
Also Published As
Publication number | Publication date |
---|---|
EP3821185A4 (en) | 2022-04-06 |
DK201970446A1 (en) | 2020-02-13 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2020011327A1 (en) | Refrigerant vapour quality measurement for optimized evaporator control and liquid distribution | |
EP1982127B1 (en) | Flow control of refrigerant | |
US8991201B2 (en) | Ejector cycle system | |
RU2417344C2 (en) | Device and procedure for control of cooling systems | |
RU2660723C1 (en) | Method for controlling ejector unit of variable capacity | |
JP4610742B2 (en) | Vapor compression apparatus and method | |
WO2017067863A1 (en) | A method for controlling a vapour compression system in a flooded state | |
US11549734B2 (en) | Method for terminating defrosting of an evaporator by use of air temperature measurements | |
CA2885755A1 (en) | Variable refrigerant charge control | |
US8640473B2 (en) | Refrigeration apparatus and method for controlling the same | |
EP2976584B1 (en) | Method and apparatus for initiating coil defrost in a refrigeration system evaporator | |
WO2008091110A1 (en) | Method and apparatus for sensing frost | |
JP2004500533A (en) | Vapor compression system and method for controlling conditions in the ambient environment | |
US11885540B2 (en) | Condensers for heating and/or cooling systems | |
EP3821185A1 (en) | Refrigerant vapour quality measurement for optimized evaporator control and liquid distribution | |
US12044450B2 (en) | Method for terminating defrosting of an evaporator | |
US20160327322A1 (en) | A method for controlling a supply of refrigerant to an evaporator based on temperature measurements | |
JP2009236428A (en) | Compression type refrigerating machine | |
Marshall et al. | Dynamic analysis of an industrial refrigeration system to investigate capacity control | |
CN107003053B (en) | For controlling the method including calculating reference temperature for arriving the cold-producing medium supply of evaporator | |
KR20170127667A (en) | condensing pressure control system for heatpump | |
WO1996041106A1 (en) | Liquid compressor cooling | |
Dumitrescu et al. | Experimental Investigation on Frost Formation in Ammonia Finned Air-Coolers | |
JPS5921964A (en) | Control system of temperature of refrigerator | |
KR20100120322A (en) | Condensing pressure control system |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE |
|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE |
|
17P | Request for examination filed |
Effective date: 20210209 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
DAV | Request for validation of the european patent (deleted) | ||
DAX | Request for extension of the european patent (deleted) | ||
A4 | Supplementary search report drawn up and despatched |
Effective date: 20220307 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: F25B 9/00 20060101ALI20220301BHEP Ipc: F25B 40/00 20060101ALI20220301BHEP Ipc: F25B 41/00 20210101ALI20220301BHEP Ipc: F25B 49/02 20060101AFI20220301BHEP |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: EXAMINATION IS IN PROGRESS |
|
17Q | First examination report despatched |
Effective date: 20231107 |