WO2016097642A1

WO2016097642A1 - Self-powered non-intrusive flow sensor and method for converting heat energy into electrical energy in a network for transporting liquids which implements such a sensor

Info

Publication number: WO2016097642A1
Application number: PCT/FR2015/053610
Authority: WO
Inventors: Louis Gorintin; Julien WERLY
Original assignee: Engie
Priority date: 2014-12-19
Filing date: 2015-12-17
Publication date: 2016-06-23
Also published as: FR3030726A1; FR3030727A1; FR3030727B1

Abstract

The present invention relates to a non-intrusive flow sensor (1) for measuring the flows of liquids passing through a network for transporting liquids, and to a method for measuring the flow of a liquid passing through a network (2) for transporting liquids by using such a sensor (1).

Description

Non-intrusive energy autonomous flow sensor and method for converting thermal energy into electrical energy on a fluid transport network employing such a sensor

The present invention relates to the field of energy recovery systems (generally referred to as "Energy Harvesting Systems" in English,) for the energy supply of instrumentation and small systems.

Electronic systems present in the industrial environment are becoming less and less energy consuming, last longer and longer and communicate more and more by radio frequency systems. In this perspective, the energy autonomy of these electronic systems is an important area of improvement that is increasingly being addressed. Today, their food is provided either by the sector or by batteries. These power solutions present a cost and technical constraints of deployment.

The goal today is to give electronic systems the ability to function for years without human intervention. The products tend for the most part to the same philosophy "Install and forget" (better known in English as "Install and Forget"), the equivalent of "Install and play" (better known in English "Plug and Play" ) multimedia devices. These systems must from their installation integrate into their environment both from the point of view of communication and food.

Fluid transport networks need to be instrumented to better monitor them and thus the case of carrying out preventive maintenance or maintenance operations. The sensors of the flow meter type make it possible to measure the flows that pass through these transport networks. The measurement can be intrusive or not, which impacts the cost of installation and the consumption of the system.

The constraints are as follows:

from a consumption point of view:

o an intrusive measure consumes little,

o a non-intrusive ultrasound measurement consumes a lot and needs to be connected to the electrical network;

from an installation point of view:

o an intrusive measure requires intervention on the pipeline which has a cost and requires the shutdown of the operating unit, which can not always be done;

o Ultrasonic measurement is easily installed outside the pipe.

The unresolved problem today is therefore on the one hand to find non-intrusive measurements and on the other hand to be able to use non-intrusive measurement sensors that can:

on the one hand, to install easily without having to require a connection to the electrical network, and

on the other hand, which work in the very long term without human intervention.

Non-intrusive flowmetering is known to those skilled in the art. It may in particular be carried out by optical or ultrasonic means. Optical methods requiring a transparent channel, this technique is only very exploitable in the industrial field without performing an intervention on the network. This would make this technique more intrusive.

In non-intrusive flowmetering, the most widely used method uses ultrasound. The principle is as follows: the transmission speed of an ultrasonic signal depends on the flow velocity of the fluid. An ultrasonic signal moves more slowly against the direction of flow. For the measurement, ultrasonic pulses are sent alternately in both directions. The difference in transit time is measured and allows an accurate determination of the flow rate.

In the context of the present invention where there is no possibility of a connection to the power grid and an impossibility of intervening on the pipeline (obligation to use a non-intrusive flowmeter), the only existing solutions answering the problem installed are necessarily to install a flow meter powered with batteries, or in the worst case not to install a flowmeter.

To increase the autonomy of the device, the existing solutions can be accompanied by battery packs recharged by the energy recovered in the environment via a transducer, in order to increase the time interval between two maintenance periods.

The non-intrusive flow metering solutions known to those skilled in the art are in particular those developed in the following patents and patent application:

The French patent FR2720839, which relates to a laser velopimeter with a portable Doppler effect,

French Patent FR2767919, which relates to a flow measurement method adapted to petroleum effluents formed from multiphase fluid mixtures which may comprise water, oil and gas, The French patent FR2616914, which concerns a device able to perform ultrasound or ultrasonic flow analysis,

The European patent application EP0932029, which relates to a fluid acoustic flowmeter comprising timing means for determining the transit time values upstream and downstream of acoustic pulses transmitted between acoustic signal transreceptors that can alternatively be operated as generators and as receivers, opposite the direction of the fluid flow,

The international application WO 93/21500, which relates to an acoustic flowmetering method and device for measuring the flow rate of a gas and / or quantities derived from it: the sound wave tube is emitted in the measuring pipe long and detects the sound signals propagating in the gas downstream and / or upstream, by means of two sonic detectors associated with the measuring pipe and separated from each other by a given distance (L), the flow (v) flowing gas in the measuring pipe being determined by correlation of said sound signals. Today, no energy-independent, non-intrusive flow metering system exists. The autonomic energy flow rate measurements are all intrusive in nature.

Failure to install a flow meter is not a satisfactory solution, as there is a lack of monitoring of fluid transport networks. This lack of information does not allow the operation of this network optimally and therefore does not meet the modern requirements of management and operation of a network.

It is therefore necessary to install a non-flow meter intrusive to answer the problem.

Only ultrasound flow meters meet this constraint in the state of the art; it is also mandatory in the state of the art, to install a battery power to increase the energy autonomy time of these flow meters. However, this has the following disadvantages:

The life of the system, maintenance-free, depends on the lifetime of the batteries which is related to their technology, their capacity according to the consumption of the electronic system, their volume which prevents to install them when the available space is reduced, and their weight.

The cost of maintenance imposed by the regular repetitive battery replacement throughout the life cycle of the electronic system: The life of an electronic card can be several tens of years where the battery life in the state of the technique can range from several weeks to several years depending on the volume available and the sustainable investment cost.

For example, in an implementation mode, a flow meter that consumes an average of 1 Watt requires, for a period of 15 days of energy autonomy:

a battery capacity representing an energy of the order of 475 Watt (1.7 Megajoules);

a volume of 4 liters.

A battery-powered solution requires a substantial material cost every 15 days, not to mention the human cost of an intervention.

However, the service life of the maintenance-free power supply system is too short and depends greatly on the capacity of the batteries installed. It is physically impossible to have both a compact system at low cost and very long life. Gold there is a contradiction between the cost of the batteries, their volume and the electrical capacity necessary to power a system over a long period.

There remains the need to be able to measure the flow rate of a fluid using a non-invasive flowmeter, which is autonomous in energy.

To meet this need, the applicant has developed a flow sensor associating a non-intrusive flowmeter coupled to a thermal energy recovery solution and a power reserve.

The fluid transport networks can for example carry hot fluids such as pressurized water vapor that can reach temperatures above 100 ° C. These hot streams carry within them a considerable amount of thermal energy. The difference in temperature between these pipes and their environment is conducive to the creation of a heat flow that propagates from the pipes to their environment.

It is this heat flow that can be harvested and converted into electrical energy.

Other hot spots can claim to be a source of thermal energy if their temperature is different from their environment. The surface of a wood stove for example can serve as a hot spot. The principle to produce electricity is then the same: to generate a heat flux and to convert it into electricity.

This principle of harvesting thermal energy in the form of a temperature difference is generally referred to in English as "Energy Harvesting". This source of energy is permanently available and its quantity depends on the difference in temperature between the pipes and their environment, that is to say the air. The more the difference in temperature is important, the heat energy harvestable is important.

In comparison with a battery supply solution, a flow sensor according to the invention which combines a battery with a thermal energy harvester offers the following advantages:

Energy autonomy of 5 years;

Reduced investment cost;

1.2 liter volume.

Battery capacity around 200 Watts (720 Kilo oule)

A harvester producing an average of 1.5 watts.

The present invention therefore relates to a non-intrusive flow sensor for measuring the flow of fluids passing through a fluid transport network, said sensor being autonomous in energy and comprising:

a flowmeter,

a thermal energy recovery system comprising: at least one thermal energy transduction module, which is either a Seebeck module or a thermomechanical module for converting a thermal gradient transiting between a hot point and a cold point into electrical energy, said module connecting said hot point and said cold point by a thermal bridge, and o at least one heat sink, disposed on said thermal energy transducer module to maximize heat flux between the hot spot and its environment and whose flow passes through said thermal energy transduction module,

an upstream voltage regulating system for transforming and transferring electrical energy produced by said thermal energy transducing module to an electrical energy storage system, and

said electrical energy storage system, which is connected to said flowmeter via a downstream voltage regulator, said sensor being characterized in that the hot spot is constituted by a pipe of said network carrying a hot fluid, and

in that the flowmeter is non-intrusive by being placed outside said duct and being able to emit, between its two ends, acoustic or electromagnetic waves, the propagation of which depends on the flow of the fluid flowing through the duct.

The flow sensor according to the invention is a solution for recovering ambient energy, in the form of a temperature difference. She permits :

deploy non-invasive flow meters over an entire network of hot fluids;

to avoid using a limited energy reserve in the form of battery and thus limits the operations of replacement of the latter;

Advantageously, the temperature difference of the outer wall of the pipe carrying the hot fluid with the surrounding medium may be greater than 3 C.

In another aspect of the invention, measurement and energy harvesting can also be performed on two different networks. The harvested energy source can be installed on any heat source.

As flowmeters usable for the flow sensor according to the invention, mention may notably be made of transit-time ultrasonic flowmeters, Doppler ultrasonic flowmeters, electromagnetic flowmeters, Doppler radar flowmeters, flowmeters by time measurement. of thermal flight, and flow meters by X-ray tomography.

Ultrasonic flow measurement allows installation on pipelines during operation, which avoids the cost of work on a network. The thermal energy recovery system of the flow sensor according to the invention comprises at least one thermal energy transduction module, which connects a hot point and a cold point by a thermal bridge, and at least one heat sink. disposed on said thermal energy transduction module.

The conversion of thermal energy into electrical energy is carried out using thermal energy transduction module. To harvest and store this energy, a Peltier or thermomechanical module alone is not enough. It must be associated with a storage system of electrical energy.

A thermal energy transduction module is either a Seebeck module (also known as "Peltier module") or a thermomechanical module.

The number of thermal energy transduction modules depends on the power required to power the flowmeter.

For the purposes of the present invention, the terms "Seebeck modules" are used: indeed, the terms "Peltier module" or "Seebeck module" refer to the same module, but their conditions of use are different.

o When this module is used to produce a

temperature difference, from an electric current, we speak of Peltier module, because it uses the Peltier effect;

when this module is used to produce an electric current from a temperature difference, it is called the Seebeck module, because it uses the Seebeck effect;

The thermal bridge is a mechanical element that adapts both to the shape of the fluid transport network and to the shape of the thermal energy transduction module. This double adaptation allows a better transmission by conduction of the heat from the hot point to said module of energy transduction.

The more the sole acting as thermal bridge is in pressure with the surface of the hot source (respectively cold), the more the temperature of the soleplate will be close to that of the hot point (respectively cold). The goal is to have the highest possible footing temperature, ie that of the hot spring.

Preferably, the system will be a thermomechanical adapter sole on a pipe.

Advantageously, the heat sink may be:

According to a first embodiment of the flow sensor according to the invention, a radiator cooled by natural or forced convection, or by radiation capable of dissipating the heat which passes through the thermal energy transduction module, or

According to a second embodiment of the flow sensor according to the invention, a conductive thermal conductor capable of dissipating the heat which passes through the thermal energy transduction module.

A heat sink makes it possible to maximize the heat flow between the thermal energy transduction module and the cold (respectively hot) source (for example, the air surrounding it). The objective is to have a heatsink temperature (the highest possible), that is to say that of the cold source (respectively hot). Preferably, this system will be a radiator.

As systems for storing electrical energy that can be used for the flow sensor according to the invention, particular mention may be made of electrochemical storage systems such as batteries and double-layer supercapacitors, and physical storage systems such as capabilities, and hybrid layer capabilities.

If a battery is used as a storage system, it is sized to operate in "floating" mode (the battery is always charged) and is used only during peak consumption of the sensor. The battery is also used to power the sensor during periods when the transport network is empty and there is no more heat.

Another subject of the present invention is a method for measuring the flow rate of a fluid transiting a fluid transport network by means of a flow sensor according to the invention, in which the electrical energy storage system supplies the flow meter with electrical energy.

Other advantages and features of the present invention will result from the description which follows, given by way of nonlimiting example and with reference to the appended figures:

FIG. 1 represents a schematic view of an exemplary flow sensor according to the invention,

FIG. 2 represents a detailed sectional view of the energy recovery system of the flow sensor illustrated in FIG. 1;

- Figure 3 shows a schematic sectional view of the non-intrusive flowmeter 10 flow sensor illustrated in Figure 1, the flow meter 10 being disposed outside of a pipe as a hot source (3).

The identical elements shown in FIGS. 1 to 3 are identified by identical reference numerals.

FIG. 1 represents a flow sensor 1 according to the invention, comprising:

a non-intrusive flowmeter 10,

a heat recovery system (11) comprising: at least one thermal energy transduction module 110, for converting into electrical energy a thermal gradient transiting between a hot point 3 and a cold point,

o this module 110 connecting the hot spot 3 and the cold point (environment) by a thermal bridge 111, and o a heat sink 112, disposed on the thermal energy transduction module,

an upstream voltage regulation system 12 for transforming and transferring the electrical energy produced by the thermal energy transduction module 110 to

o an electrical energy storage system 13, which is connected to the flow meter 10 via a downstream voltage regulator 132.

FIG. 2 shows in greater detail the thermal energy recovery system 11 of the flow sensor 1 according to the invention shown in FIG. 1. The hot point 3 here consists of a pipe of a network transporting a hot fluid. . Line 3 is in contact with a thermal bridge 111 making a contact between itself and the thermal energy transduction module 110 (which is in the case illustrated in Figure 2 a Seebeck module). A heat sink 112, here a radiator, in contact with the Seebeck module 110, maximizes the heat exchange between the Seebeck module 110 and its environment 4 (constituting the cold spot).

Thus a heat flow passes between the hot point 3 and the cold point 4 and a portion of this flow is converted into electricity via the Peltier module 110.

FIG. 3 shows in more detail a non-intrusive flowmeter 10 of flow sensor 1 according to the invention shown in FIG. 1. FIG. the flowmeter 10, placed outside a pipe constituting the hot source 3 emits, between its two ends, waves that can be acoustic or electromagnetic. Their propagation is influenced by the flow rate of the fluid flowing in line 3.

Claims

1) non-intrusive flow sensor (1) for measuring the flow of fluids passing through a fluid transport network (2), said sensor (1) being energy autonomous and comprising:

a flowmeter (10),

a heat recovery system (11) comprising: at least one thermal energy transduction module

(110), which is either a Seebeck module, or a thermomechanical module for converting a thermal gradient transiting between a hot spot (3) and a cold spot (4) into electrical energy, said module (110) connecting said hot spot (3) ) and said cold point by a thermal bridge

(111), and

at least one heat dissipator (112), disposed on said thermal energy transduction module (110) for maximizing the heat flux between the hot spot (3) and its environment and whose flow passes through said transduction module of thermal energy (110),

an upstream voltage regulating system (12) for transforming and transferring electrical energy produced by said thermal energy transducing module (110) to an electrical energy storage system (13), and

said electrical energy storage system (13), which is connected to said flowmeter (10) via a downstream voltage regulator (132).

said sensor being characterized in that the hot spot (3) is constituted by a pipe (3) of said network (2) carrying a hot fluid, and

in that the flowmeter (10) is non-intrusive by being placed outside said duct (3) and being able to emit, between its two ends, acoustic or electromagnetic waves, the propagation of which depends on the flow of the fluid circulating within the pipe (3).

2) Flow sensor (1) according to claim 1, wherein the temperature difference of the outer wall of the pipe (21) carrying the hot fluid with the surrounding medium is greater than 3 C.

3) flow sensor (1) according to claim 1 or claim 2, wherein the flow meter (10) is a transit time ultrasonic flowmeter, or a Doppler ultrasonic flowmeter, or an electromagnetic flowmeter, or a flowmeter. Doppler radar, or a flowmeter by thermal flight time measurement, or a flow meter by X-ray tomography.

4) Flow sensor (1) according to any one of claims 1 to 3, wherein the heat sink (112) is a radiator cooled by natural or forced convection, or radiation capable of dissipating the heat that passes through through the thermal energy transduction module (110).

5) flow sensor (1) according to any one of claims 1 to 3, wherein the heat sink (112) is a conductive thermal conductor capable of dissipating the heat that passes through the transduction module of thermal energy (110).

The flow sensor (1) according to any one of claims 1 to 5, wherein the electrical energy storage system (12) is a dual layer battery, or capacity, or supercapacity, or capacitance hybrid layer.

7) Method for measuring the flow rate of a fluid transiting in a fluid transport network (2) using a non-intrusive flow sensor (1) as defined in any one of claims 1 to 6, wherein said electrical energy storage system (12) supplies the flow meter with electrical energy (10).