EP3751209A1 - Procédé mis en uvre par ordinateur, programme informatique et système de surveillance de fuites de gaz réfrigérant dans un système de réfrigération - Google Patents

Procédé mis en uvre par ordinateur, programme informatique et système de surveillance de fuites de gaz réfrigérant dans un système de réfrigération Download PDF

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Publication number
EP3751209A1
EP3751209A1 EP19382489.3A EP19382489A EP3751209A1 EP 3751209 A1 EP3751209 A1 EP 3751209A1 EP 19382489 A EP19382489 A EP 19382489A EP 3751209 A1 EP3751209 A1 EP 3751209A1
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EP
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Prior art keywords
leak
refrigerant gas
concentration
refrigerant
time
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EP19382489.3A
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German (de)
English (en)
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EP3751209C0 (fr
EP3751209B1 (fr
Inventor
Xavier ALBETS CHICO
Miguel Angel GONZÁLEZ SÁNCHEZ
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Ako Electromecanica SAL
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Ako Electromecanica SAL
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Priority to EP19382489.3A priority Critical patent/EP3751209B1/fr
Priority to ES19382489T priority patent/ES2970806T3/es
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/32—Responding to malfunctions or emergencies
    • F24F11/36—Responding to malfunctions or emergencies to leakage of heat-exchange fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • 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
    • F25B2500/22—Preventing, detecting or repairing leaks of refrigeration fluids
    • F25B2500/222—Detecting refrigerant leaks

Definitions

  • the present invention generally relates, in a first aspect, to a computer implemented method for monitoring refrigerant gas leaks in a refrigeration system, and more particularly to a method which provides an estimation of the severity of the leak.
  • a second and a third aspect of the invention respectively relate to a computer program and a system for monitoring refrigerant gas leaks in a refrigeration system which implement the method of the first aspect of the invention.
  • refrigeration end-users owners of several thousands of HFC-based commercial and industrial refrigeration installations with high or very high leak rates (between 15% and 35% of total charge per year) depend upon big amounts of fresh refrigerant to replace the leaked quantities, refrigerant that is needed in order to maintain both refrigeration systems and their business models operational. This is especially troubling for refrigeration installations that were designed and commissioned during the last 10 years (not fully amortized) that are fully operational and efficient, despite their leakages and their dependency upon big amounts of refrigerant.
  • Refrigeration end-users are, therefore, facing a challenging scenario where decisions are difficult to make.
  • the present invention relates, in a first aspect, to a computer implemented method for monitoring refrigerant gas leaks in a refrigeration system, comprising:
  • the method of the first aspect of the invention comprises computing the above mentioned leak severity indicator based on a mass conservation model that relates concentration values to refrigerant gas leak intensity, within a volume, density of the refrigerant gas, and modelled diffusion and convection terms, A and B, of the refrigerant gas which leaves said volume.
  • the above mentioned computing of the leak severity indicator comprises extrapolating the same from a plurality of modelled values for the mean time integral of said diffusion and convection terms, A and B , for a corresponding plurality of values of reference concentrations c ref , and reference volumes V ref .
  • c stands for the concentration measurements
  • V for the predetermined volume
  • T is a finite filtering/averaging period of time
  • L ( T ) is the refrigerant gas leak intensity averaged along T
  • A(t, Cref ) and B(t,c ref ) are said diffusion and convection terms, A and B , for the reference concentration C ref and reference volume V ref to be integrated for a time t going from 0 to T.
  • the leak severity indicator is L ( T ) , expressed as the estimation of leaked refrigerant mass per hour, while for an alternative or complementary embodiment the leak severity indicator is a Leak Potential Index (LPI) computed from L ( T ) as the estimation of leaked refrigerant mass per year, or the estimation of equivalent tones of CO 2 per year (assuming the leak is constant and remains unattended throughout the following year).
  • LPI Leak Potential Index
  • the method of the first aspect of the present invention comprises computing a further leak severity indicator which is a Leak Charge Index (LCI) obtained by dividing the Leak Potential Index (LPI), when expressing the estimation of leaked refrigerant mass per year, by the total charge of refrigerant of the refrigeration system.
  • LCI Leak Charge Index
  • the method of the first aspect of the present invention further comprises locating the refrigerant gas leak by performing the above mentioned detection and measuring step with several refrigerant gas detectors placed at different locations and forming at least one set of n refrigerant gas detectors configured and arranged for operating for the above mentioned predetermine volume, and triangulating the refrigerant gas leak spatial coordinates from the concentration measurements provided by the several refrigerant gas detectors and the spatial coordinates thereof.
  • the method comprises carrying out the above mentioned triangulation based on the different time-concentration behaviour of the refrigerant gas detectors.
  • the method of the first aspect of the present invention comprises carrying out said triangulation by sequentially performing the following steps:
  • the method further comprises computing a leak time indicator expressed by means of a Time-Gas Concentration Index (TGCI) by hourly averaging during several days the measured refrigerant gas leak concentration.
  • TGCI Time-Gas Concentration Index
  • a second aspect of the present invention relates to a computer program, comprising program code instructions that when run in a computer or a processor implement the steps of the method of any of the previous claims.
  • the present invention relates to a system for monitoring refrigerant gas leaks in a refrigeration system, comprising:
  • the at least one computing entity comprises storage means for storing data representative of said plurality of modelled values for the mean time integral of the diffusion and convection terms, A and B, and of the corresponding plurality of values of reference concentrations c ref , and of the reference volumes V ref , and wherein the at least one computing entity is adapted to process the stored data to extrapolate the leak severity indicator therefrom according to any of the above described embodiments of the method of the first aspect of the present invention.
  • system of the third aspect of the present invention comprises a graphical user interface operatively connected to the computing entity to graphically display values obtained for any of the above mentioned leak severity indicator, further leak severity indicator, and/or leak time indicator.
  • an additional low-cost alternative to the prior art methods/systems is provided: a method/system to detect and localize refrigerant gas leaks at very early stages and, consequently, prevent refrigerant gas leakage in sensitive amounts without the need of constant, expensive and, sometimes, unfruitful maintenance leak inspections.
  • proper leak categorization through the computing power for example, on an internet-server or cloud system
  • concentration readings particles per million: ppm
  • leak intensity kg/year
  • the present invention is able to generate both types of information, concerning environmental/economical and safety points of view (as the concentration level is preferably also reported), being the latter the only approach nowadays in refrigeration applications.
  • the system of the third aspect of the present invention prioritizes detected refrigerant gas leaks in a parametric manner (modifiable by the stakeholders of the refrigeration system, based in severity, time, location and safety aspects of the leak, among others) and consequently informs, warns and alerts a list of selected stakeholders using cellular telephony and/or internet technology (such as but not limited to 3G, 4G, 5G, Narrow Band based, SMS, e-mail, telegram app, etc.).
  • cellular telephony and/or internet technology such as but not limited to 3G, 4G, 5G, Narrow Band based, SMS, e-mail, telegram app, etc.
  • the system of the third aspect of the present invention is also able, for some embodiments, to trace the refrigerant gas leak as explained above, i.e. by convoluting/triangulating surrounding networked sensors/transmitters which might help to indicate the most probable leak position (for example in supermarket ceilings, leak information of three or more sensors/transmitters in a common confined ceiling area will be used to triangulate the potential leak spot) thus exponentially minimizing repair time to locate the leak, therefore minimizing refrigerant vented to the atmosphere.
  • the system of the third aspect of the present invention is also able to identify the most probable time of the day/week/month for the refrigerant gas leak to happen based on statistical analysis of concentration readings, therefore being able to indicate the most probable leak time (this is especially useful when leaks are related to specific refrigeration maneuvers that are not constant in time).
  • the system of the third aspect of the present invention is also able, for example through internet technology, to summon leak information of different sensor/transmitter sets based on installation, location, company, contractor, etc. helping to analyze/compare leak-related failure rates and therefore maintenance or construction standards based on such criteria.
  • the smart early detection system for gas leaks in refrigeration applications proposed by the third aspect of the present invention is composed, for the here described working embodiment, by three main components: i ) on-site early detection by means of sensitive sensors/transmitters, ii ) a connectivity method to communicate the on-site information to a third component: iii ) a computing platform where the information is registered, analysed and leak indicators are computed.
  • the three components are briefly described below for a specific implementation.
  • MOS Metal Oxide Semiconductor
  • NDIR Non Dispersive Infrared
  • PIR Photoacoustic Infra-Red
  • sensitivity is below 10 ppm and both selectivity and accuracy are generally high or very high.
  • NDIR Non Dispersive Infrared
  • PIR Photoacoustic Infra-Red
  • the specific implementation of the system here presented makes use of a distributed network of NDIR sensors with accuracy/precision below 2% error, high selectivity and sensitivity below 5 ppm.
  • the sensors are integrated into an on-site robust filtering device (transmitter) that reads the sensor information such that it can be communicated via different means, as discussed below.
  • the connectivity between the on-site sensing devices/transmitters and the computing platform is very important in terms of system performance, and is also related to system robustness and, obviously, acquisition cost.
  • the connectivity being a critical accessory of the smart early detection system, the system here in consideration is able to connect the network of on-site transmitters and the computing platform in different ways, wired or wirelessly (such as by means of Wi-Fi or mobile telecommunication networks), although for the here described implementation the connection is provided in two different ways: through a wired RS-485 communication bus using MODBUS protocols which centralizes the information in a local gateway which in its turn sends the information to an internet-based computing platform; or alternatively, through on-site transmitter that account for IoT (Internet of Things) cellular telecommunication modules.
  • IoT Internet of Things
  • Such communication modules are based on Narrow Band technology and they allow to directly send the on-site read sensors/transmitters information to the server-based computing platform, without going through wiring and on-site internet accessibility facilities, factors that are always related to
  • the computing platform represents the core of the smart early detection system, as it is the component in charge of translating data (concentration readings, time, etc.) into leak information and the consequent notifications and alarms. Such reporting will prompt an early stage localization and repair of the refrigerant gas leak by the refrigeration system end-user or contractor, before important refrigerant losses are vented to the atmosphere.
  • the computational platform is also responsible for assessing the correct status of the refrigerant sensors/transmitters, registering the raw data, managing the notifications and alarms per transmitter, registering refrigerant gas leak information and auditing leak actions: namely time of detection, time of repair and details about the leak repair that might become meaningful for maintenance processes, such personnel involved, cause of the leak and actions that were taken.
  • the computing platform is placed locally (pc-based) or remotely (internet server-based), or is distributed between local and remote computing entities.
  • the computing platform is also able to triangulate the refrigerant gas leak information of several gas sensors/transmitters of their corresponding set that share a common volumetric surrounding in order to locate the refrigerant leak, as explained above, for example by using any of the Indoor Positioning System (IPS) available nowadays and/or a manual positioning system parameterized throughout the commissioning of the system by using standard position techniques: x,y,z.
  • IPS Indoor Positioning System
  • Such computing platform is also preferably able to communicate the generated information (indicators, statistics, plots, etc.) to multiple stakeholders of the refrigeration system through several telecommunication technologies and devices, stating: position, probable leak time and severity of the leak in first term, besides standard safety alarms, among other indicators.
  • a network of NDIR transmitters is deployed around the refrigeration apparatus, placing transmitters in the volumes with higher probability of leakage: compressor rooms, cold-rooms and/or above cold-rooms ceilings, refrigerated cabinets, liquid lines (usually in reduced volume ceilings) and condensing units.
  • a good compromise between leak probability detection and acquisition cost might be between 10 and 25 sensing points for a standard supermarket, for instance.
  • the system parameterizes, among others aspects, the following meaningful information per transmitter:
  • the computing platform receives the readings of the sensors/transmitters (located at different locations of the refrigeration system) at a given frequency, which is smaller than 1 hour, and performs the above described computing of leak indicators and leak location.
  • a change of concentration is detected by the closest transmitter and/or transmitters, which sends the information to the computing platform.
  • an alarm or notification is sent, together with the respective leak indicators: severity (by modelling the leak intensity), localization (by triangulation when possible, as further detailed) and probable leak time, in the case the leak presents some time pattern related to specific refrigeration processes.
  • severity by modelling the leak intensity
  • localization by triangulation when possible, as further detailed
  • probable leak time in the case the leak presents some time pattern related to specific refrigeration processes.
  • all three indicators provide meaningful information for the early repair: where, when and how severe is the leak (weight of refrigerant or mass that is lost to the atmosphere).
  • the early detection of the refrigerant gas leak captured by the on-site transmitters require of leak indicators for an efficient management, quick localization and repair.
  • the calculations of the leak indicators are performed at the computing platform, as computing power and some system considerations are needed.
  • This section will present the technical basis for the TGCI (Time-Gas Concentration Index) as a leak time indicator, the LPI (Leak Potential Index) and the LCI (Leak Charge Index) as leak severity indicators and, finally, the coordinates LX, LY and LZ, i.e. leak coordinates or leak predominant coordinate, when applicable.
  • the computing platform is able to estimate leak severity when terms A & B are modelled and the approximate volume of the application V is specified (it is therefore needed to define the corresponding volume of detection for each on-site transmitter during commissioning). As said, the computing platform reads and registers the refrigerant concentration at a defined monitoring frequency.
  • the Leak Potential Index is computed as the estimation of leaked kg refrigerant per year or, alternatively, tons of CO 2 per year, making use of the GWP of the refrigerant of the system (if parameterized at the computing platform) assuming that the computed leak will remain unattended and constant throughout the year.
  • This indicator allows to assess the severity of the leak from both economic and environmental points of view if left unattended and, therefore, manage its priority in terms of on-site inspection and repair.
  • a second severity indicator is computed at the platform.
  • This index is obtained by dividing the yearly estimated leak (LPI in kg/year) by the total charge of refrigerant of the installation (kg), hence stating the % of refrigerant system loss that will be produced by the detected refrigerant gas leak, if left unattended.
  • the LPI and the LCI indicators are displayed as a number by the system, as depicted in Figure 1(b) . It is important to mention that computing the severity of the leak from the concentration reading is essential for the industry, as the effects of the leak on the concentration are clearly not linear and, therefore, the concentration reading is not a good indicator -sometimes even misleading- to acknowledge the leak severity.
  • An important refrigerant gas leak early detection support indicator is the triangulation of the leak coordinates based on several concentration readings from different transmitters. As the reader may infer, when only one transmitter is placed in a volume V , such triangulation process is not possible, being the spatial coordinates of the on-site transmitter the best guess for the leak coordinates. On the other hand, when several transmitters share a generally extended volume (for instance, an industrial cold room or a suspended ceiling), the different time-concentration behaviour of the transmitters can be used to estimate the leak position, making use of the transient term of the refrigerant leak modelling defined above.
  • the computing platform requires the spatial coordinates ( x , y , z ) for all system transmitters (coordinates defined either by Indoor Positioning Systems IPS or manually, together with user-defined reference coordinates at the commissioning of the system). Additionally, the computing platform requires tagging sets of neighbour transmitters, for those that share a volume V (neighbour tagging also performed during commissioning).
  • the computing platform assigns a count-down decreasing time t leak to all neighbourhood set of transmitters.
  • each transmitter ranging from 1 to N
  • t leak the count-down time for the neighbour set of transmitters.
  • the respective time t n leak (count-down time required for the concentration to reach such steady-state by transmitter n ) is used to compute the leak time-stabilisation concentration TC for each transmitter, as explained by equation 5.
  • the last transmitter of the set to reach a stable concentration will present a smaller leak-time than those closer to the leak (as leak-time is a decreasing but positive number).
  • High leak time-concentration values will be associated to closer positions to the refrigerant gas leak (higher concentration and faster leak-time), while low leak time-concentration values are typical of further positions with respect to the leak (lower concentrations and slower leak-time).
  • the regression model provides the polynomial TC fit (x) that produces the minimum least squares with respect the actual values of TC(x).
  • different polynomials can be obtained (linear, cubic, etc.). If an acceptable correlation is obtained (coefficient of determination R 2 >0.6) for any of the three polynomial fittings performed ( TC fit (x), TC fit (y), TC fit (z) ) a maximum analysis of each fitted polynomial -per coordinate- can be carried out, as shown by equation 7 for the x-coordinate:
  • ppm concentration of refrigerant within a volume around (and outside) the refrigeration system, alerting when the volume is not safe for people.
  • gas detectors measure the consequence of the leak in the air surrounding the system (concentration of refrigerant diluted in air), but they never measure the severity of the cause of the leak in operational and business terms (mass of refrigerant gas leaked per hour or kg/year) that causes such concentration in the surrounding volume.
  • the present invention describes a method to correlate concentration and severity of the leak.
  • LPI Leak Potential Index
  • LCI Leak Charge Index
  • the smart early detection system immediately identified the leak after commissioning (as the leak existed before the deployment of the detection system).
  • the leak is computed as 5.62 g/h, being the LPI (Leak Potential Index) of 49.29 kg/year and the LCI (Leak Charge Index) of 35.2%, as the system accounted for 140 kg nominal refrigerant charge.
  • LPI Leak Potential Index
  • LCI Leak Charge Index
  • the owner had an easy decision to make, as the cost of the estimated leak was around 7750 € annually, including man-hours for the refrigerant refilling. The evaporator replacement was then finally carried-out, saving around 6500 € in the current year.
  • a detection system in a supermarket presents 3 sensors with readings different from 0 ppm (0 ppm is the expected reading when no leak is present). Therefore, the maintenance team asserts that 3 leaks are detected.
  • the maintenance team is not able to prioritize which of the leaks is more urgent, if any, based on the concentration readings.
  • the LPI indexes show the following information: Leak A (12 kg/year), Leak B (87 kg/year), Leak C (112 kg/year).
  • Leak A (12 kg/year)
  • Leak B 87 kg/year
  • Leak C (112 kg/year).
  • the maintenance team decides to urgently address only leaks B and C, which are causing a big deficit of refrigerant per hour.
  • Leak A is kept under surveillance and most likely, the refrigerated display will be replaced only if LPI exceeds 20 kg/year.
  • a concentration reading is obtained in an industrial cold room of 5000 m3.
  • a very low concentration is obtained (12 ppm) only during 8 h per day.
  • the LCI indicator however, after averaging concentration along the day (4 ppm) and for the volume in consideration returns 178 kg/year (around 25 000 € / year). With this information, inspection and repair is launched, despite the extremely low concentration read.
  • a supermarket small cabinet (with total cost of 300 €) is showing a concentration of 234 ppm in average. Repair is not possible, although the owner hesitates to replace the cabinet as the cost of the leak is unknown.
  • the LPI 36 kg/year shows that the cost of keeping the cabinet (refrigerant R134A at 100 €/kg) is about 10 times the price of the cabinet itself (per year), so replacement is mandatory.
  • a refrigeration contractor is in charge of the maintenance of 10 supermarkets in Barcelona. All supermarkets have a smart refrigeration detection system, centralized in a computing platform in the "cloud" (internet server). On Monday one warning based on the concentration of a cold-room in supermarket 1 is obtained at 34 ppm. At the same time, a refrigerated display in supermarket 8 indicates 201 ppm. The contractor only has two available technicians and needs to decide to which supermarket address first, if any. The LPI of the leaks are of 9 kg/year in supermarket 1 and 11 kg/year in supermarket 8, so similar values. On the other hand, the LCI for supermarket 1 is 3 % (300 kg of nominal charge) while the LCI for supermarket 8 is 110%, as the supermarket is very small and the refrigerant nominal charge is 10 kg.
  • the contractor based on this information, understands that the leak in supermarket 8 is relatively more important and needs to be addressed quickly, as every week the refrigerant charge drops by more than 2% of the total refrigerant charge, i.e. the same than the refrigerant gas leak during all year long for supermarket 1, which can be addressed next month when technicians are planned for regular maintenance work (as in 1 month only 0.25% of total system charge will be leaked).
  • Refrigeration systems have historically leaked big amounts of refrigerant because a complete leak-tight system is very difficult to achieve (as the refrigeration system is composed by multiple moving parts) and, moreover, it is not static, i.e. a completely leak tight system (as delivered in day 1) might start leaking in day 2 again due to vibration, corrosion and other factors related to the aging of the system, without any kind of accident.
  • HFC refrigerants are colourless and odourless so detection is extremely difficult.
  • frequent leak inspection processes are needed to ensure the system is free of leaks.
  • the system comprises four sensors/transmitters (A, B, C and D) which share a volume, being sensors/transmitters B and C inside a second area surrounded by walls but yet sharing a common volume with sensors/transmitters A and D.
  • sensors/transmitters A, B, C and D have been related to a neighborhood set of sensors/transmitters.
  • Sensors/transmitters are located in different points of the shared volume, defined by coordinates x,y,z, as shown below: Sensor/Transmitter Coordinates x y z A 0 0 -10 B 10 0 0 C 20 0 0 D 30 0 10
  • Table 2 shows the refrigerant concentration per sensor/transmitter with respect to absolute time obtained from the sensors of Figure 7 .
  • Figure 8 shows the time evolution of the 4 sensors/transmitters of the neighbourhood set of Figure 7
  • Table 3 below shows the time concentration per sensor/transmitter with respect to leak time, defined by sensor/transmitter C (the first one to detect a concentration change, for this example).
  • the marked cells contain the values that define that a steady-state is reached by each sensor/transmitter.
  • Table 4 shows the steady-state time-concentration values for further polynomial adjustment in order to determine de leak coordinates.
  • Table 4 Transmitter/Sensor Coordinates Steady-state reached at relative time (s) Time-concentration at steady-state (ppms) x y z A 0 0 -10 480 9600 B 10 5 0 1680 67200 C 20 0 0 2760 165600 D 30 0 10 1920 9600
  • the leak position is displayed by Figure 12 .
  • the refrigerant piping of a hypermarket is placed above a ceiling.
  • the ceiling covers all the surface of the hypermarket (10 000 m2).
  • the amount of piping and valves in such area is very important (hundreds of meters of piping and dozens of valves to feed the evaporators of cold-rooms and refrigerated cabinets/displays of the hypermarket).
  • the inspection of this area is very difficult, as the piping is suspended from the ceiling and there is no easy access to the area.
  • a logistic centre of a supermarket chain has 6 industrial cold-rooms of 5000 m3 average each.
  • the total charge of refrigerant of the system is 1900 kg of R448A.
  • the owner installs a smart detection system in the logistic centre using only 6 transmitters (one per cold-room).
  • a leak take places on top of cold-room 3 causing 4 out of the 6 transmitters to detect concentration.
  • the triangulation of the leak and the positioning of the gas detectors at different coordinates allows to locate the leak in the above cold room area of cold room 4.
  • Figure 3 describes the local installation of the gas sensors/transmitters.
  • Figure 4 schematically illustrates the system of the invention applied to the described ( Figure 3 ) commercial refrigeration system (supermarket); which comprises a set of 9 NDIR-based R134a refrigerant transmitters, a wiring bus (based on MODBUS protocols) and a local computing platform.
  • Each refrigerant transmitter is composed by a highly sensitive autonomous Non Dispersed Infra-Red (NDIR) gas sensor and a transmitter, i.e. a filtering/communicating device that reads the sensor, filters the signal and eventually communicates to the computing platform through a wired MODBUS engineered communication channel.
  • NDIR Non Dispersed Infra-Red
  • the computing platform is able to assign a set of parameters for each transmitter (such as although not limited to):
  • the computing platform can also accept general parameters that define general aspects for the set of sensors/transmitters of the system (group tags) what can be useful for statistical analysis relating different installed systems.
  • the present invention proposes a system able to detect refrigerant leaks at early stages (low, moderate refrigerant mass flow rates of the order of grams per hour), estimate location and most probable time to locate the leak, register data, quantify, categorize and prioritize the leak severity.
  • any sufficiently important refrigerant leak located in the surrounding area of the sensor/transmitter will trigger either a concentration reading and/or a change of the concentration reading of the sensor/transmitter.
  • a concentration reading or its respective change are detected and real-time communicated to the computing platform, a calculation relating the concentration reading, the change in time of the concentration reading and the volumetric area assigned to the sensor/transmitter will be translated to an estimation of the refrigerant mass flow (grams/hour) happening in the sensor/transmitter surrounding area thanks to a model that will be described further down.
  • This information will be automatically transformed into kg/year to leak (if leak unattended) what is the so-called LPI (Leak Potential Index).
  • the LPI allows to the stakeholder to clearly understand the severity of the leak and to categorize its priority to be finally located and repaired. Indeed, given the economic cost of the refrigerant gas and its GWP (Global Warming Potential), an estimation of economic cost of the leak and the equivalent CO2 tons, among other parameters, is associated to the leak ( €/year, eq. tons CO2/year, etc.). As said, specifics about the computation of this index are detailed further down.
  • TGCI Time-Gas Concentration Index
  • the TGCI is an indicator that distributes concentration readings hourly, daily or weekly (as parameterized by the system user) such that it can correlate the most probable hour/day/week to locate the leak, in the case it is not constant in time (which is the case in the most complex refrigerant leaks, happening only under very specific refrigeration system maneuvers).
  • the index is presented as a histogram for 0-24h, 1-7 days of the week and 1-31 days of the month. Specific computation of the index is detailed further down.
  • the computing platform also relates the indicators of all sensors/transmitters in real time as those could be related to the same refrigerant leak and/or different leaks happening at the same time.
  • an algorithm can linearize up to 3 dimensions the concentration reading and the concentration change in time associated to each affected sensor/transmitter and decide either the same leak is responsible for the outputs or multiple leaks are taking place simultaneously. The specific way to triangulate the location is also detailed further down.
  • the computing platform Based on these indicators (severity, location and time), the computing platform triggers alarms that are sent through several telecommunication platforms to the stakeholders of the refrigeration system.
  • FIG. 5 schematically illustrates the system of the invention which also comprises a set of 9 NDIR-based R134a refrigerant transmitters T1-T9, in this embodiment connected through Narrow Band cellular (wireless) internet telecommunication technology to an internet server (internet server hereafter referred as "cloud").
  • Each refrigerant transmitter is composed by a highly sensitive autonomous Non Dispersed Infra-Red (NDIR) gas sensor and a cellular transmitter, i.e. a filtering/communicating device that reads the sensor, filters the signal and on-demand communicates to the computing platform (at cloud) through Narrow Band cellular (wireless) internet telecommunication technology provided by commercial telecommunication operators.
  • NDIR Non Dispersed Infra-Red
  • FIG. 6 A slight variation is shown in Figure 6 , for which the 9 NDIR-based R134a refrigerant transmitters are connected through a Wi-Fi based network to a computing platform at cloud via a local computing platform and/or a bridge or gateway.
  • the principle of operation is identical as the preferred embodiment 1, interchanging the way transmitters are connected to the computing platform.
  • a communication can be forced to the cloud (or just registered, depending on the communication specifications as defined by the user), where the computing platform receives the information and performs the computations and delivers the indicators.
  • This aspect must be underlined with respect to the preferred embodiment 1, where communication is continuously held through a wired bus in real time.
  • communication can be customized by the user, for example transmitting only when needed (potential leak detected) or following a regular frequency.
  • an additional functionality is based on the user-defined characterization of the communication policy between transmitters and computing platform ("cloud"), as communication can be specified regularly (once per minute, per hour, per day, etc.) while all collected events and reports are communicated at once; or communication can be specified as regular but forcing special transmissions in case of warnings, and/or pre-alarms and/or alarms; and/or combinations of the two scenarios (only regular transmission frequency or only event-triggering transmissions).

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fuzzy Systems (AREA)
  • Mathematical Physics (AREA)
  • Signal Processing (AREA)
  • Examining Or Testing Airtightness (AREA)
  • Air Conditioning Control Device (AREA)
EP19382489.3A 2019-06-13 2019-06-13 Procédé mis en oeuvre par ordinateur, programme informatique et système de surveillance de fuites de gaz réfrigérant dans un système de réfrigération Active EP3751209B1 (fr)

Priority Applications (2)

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EP19382489.3A EP3751209B1 (fr) 2019-06-13 2019-06-13 Procédé mis en oeuvre par ordinateur, programme informatique et système de surveillance de fuites de gaz réfrigérant dans un système de réfrigération
ES19382489T ES2970806T3 (es) 2019-06-13 2019-06-13 Un método implementado por ordenador, un programa de ordenador y un sistema para monitorizar fugas de gas refrigerante en un sistema de refrigeración

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EP19382489.3A EP3751209B1 (fr) 2019-06-13 2019-06-13 Procédé mis en oeuvre par ordinateur, programme informatique et système de surveillance de fuites de gaz réfrigérant dans un système de réfrigération

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EP3751209A1 true EP3751209A1 (fr) 2020-12-16
EP3751209C0 EP3751209C0 (fr) 2024-01-03
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11971183B2 (en) 2019-09-05 2024-04-30 Trane International Inc. Systems and methods for refrigerant leak detection in a climate control system

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US20110112814A1 (en) * 2009-11-11 2011-05-12 Emerson Retail Services, Inc. Refrigerant leak detection system and method
CN106705384A (zh) * 2017-02-09 2017-05-24 美的集团股份有限公司 冷媒泄漏的提醒方法及装置和空调器
US20180017299A1 (en) * 2016-07-15 2018-01-18 Honeywell International Inc. Detecting refrigerant leak in a refrigeration system
US20180187917A1 (en) * 2015-08-07 2018-07-05 Mitsubishi Electric Corporation Refrigeration cycle apparatus and refrigeration cycle system

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US20110112814A1 (en) * 2009-11-11 2011-05-12 Emerson Retail Services, Inc. Refrigerant leak detection system and method
US20180187917A1 (en) * 2015-08-07 2018-07-05 Mitsubishi Electric Corporation Refrigeration cycle apparatus and refrigeration cycle system
US20180017299A1 (en) * 2016-07-15 2018-01-18 Honeywell International Inc. Detecting refrigerant leak in a refrigeration system
CN106705384A (zh) * 2017-02-09 2017-05-24 美的集团股份有限公司 冷媒泄漏的提醒方法及装置和空调器

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11971183B2 (en) 2019-09-05 2024-04-30 Trane International Inc. Systems and methods for refrigerant leak detection in a climate control system

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ES2970806T3 (es) 2024-05-30
EP3751209B1 (fr) 2024-01-03

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