A device and method for measuring well depth based on radiation cooling principle

Abstract

The present invention belongs to the field of optical devices. In order to solve the problem that the well depth cannot be measured by passive power supply at night, a device and method for measuring the well depth based on the radiation cooling principle are disclosed. The device and method include an anti-flow air layer, an emission layer of radiation cooling material, and a reflection layer with high reflectivity of sunlight in the direction of the sky. The anti-flow air layer is used to prevent moisture and flowing air in the well from affecting the measurement results of the device. The emission layer of the radiation cooling material is used to radiate heat to the outer space through a transparent window of 8 to 13 microns in the atmosphere. The reflection layer with high reflectivity of sunlight is used to reflect more than 90% of sunlight in the 0.3 to 25 micron band, thereby reducing heat absorption. The technical solution can use a radiation cooling device to achieve well depth measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic devices, and in particular to a device and method for measuring well depth based on the radiation cooling principle. Background Art

[0002] Refrigeration is an important final energy use worldwide and a major driver of peak electricity demand. At night, passive cooling below ambient air temperature has been demonstrated using a technique known as radiative cooling, which uses a device exposed to the sky to radiate heat to outer space through a transparent window of 8 to 13 microns in the atmosphere. During the day, radiative cooling is achieved using a thermophotonic approach, using an integrated photonic solar reflector and thermal emitter that reflects more than 90% of incident sunlight from 0.3 to 25 microns while emitting strongly and selectively at the atmospheric transparent window.

[0003] Existing methods for measuring depth include: sounding hammer, sounding ruler, echo sounder, well depth gauge, etc. However, the sounding ruler will produce measurement errors due to ruler stretching, curling, wear and pulley offset, which greatly affects the length measurement; the well depth gauge needs a battery or power supply for active power supply measurement, and it is difficult to use without electricity or power supply; the echo sounder measurement requires contact return measurement, which requires the sound wave to contact the object and then return the signal; the photoelectric logging ruler also needs to contact the water surface or object to send out a photoelectric signal; the logging ruler measurement requires the scale of the ruler to be observed during the day to complete the depth measurement. Summary of the invention

[0004] The present invention provides the following technical solution to solve the problem that the well depth cannot be measured passively with power supply at night: a device for measuring the well depth based on the radiation cooling principle, which includes an anti-flow air layer, an emission layer of radiation cooling material and a reflection layer with high reflectivity of sunlight in the direction of the sky, wherein the anti-flow air layer is used to prevent the moisture in the well and the flowing air from affecting the measurement result of the device;

[0005] The said emitting layer of the radiation cooling material is used to radiate heat to outer space through a transparent window of 8 to 13 μm in the atmosphere;

[0006] The reflective layer with high sunlight reflectivity is used to reflect more than 90% of sunlight and reduce heat absorption.

[0007] Preferably, the reflective layer uses a metal reflective mirror or a plane reflective mirror including a reflective film layer.

[0008] Preferably, the emission layer uses a radiation cooling material.

[0009] Preferably, the emission layer is located above the reflection layer, and the emission layer is located within the plane area of ​​the reflection layer.

[0010] Preferably, the operating wavelength of the device is 0.3-19 μm.

[0011] The present invention also provides a method for measuring well depth based on the radiation cooling principle, specifically:

[0012] Step 1: Place a second thermocouple between the reflective layer and the emitting layer;

[0013] Step 2: Place a first thermocouple between the emitter layer and the air layer;

[0014] Step 3: The second thermocouple between the reflective layer and the emitting layer measures the radiative cooler temperature T cool , the first thermocouple measurement between the emission layer and the air layer is T amb , the difference in the measurement results is the temperature difference ΔT = T amb -T cool ; Finally, the windshield is formed by encapsulating with an encapsulating film;

[0015] The temperature reduction of the radiant cooler satisfies the following relationship:

[0016] Temperature is T cool When a radiation cooler with an area of ​​A is exposed to sunlight, it is subjected to solar irradiance and atmospheric thermal radiation (corresponding to the ambient air temperature T amb ) Figure 3 , which is a schematic diagram of the structure of the radiation cooler after being illuminated. Most of the heat is dissipated through thermal radiation and reflection, thus achieving radiation cooling.

[0017] Net cooling power P of the radiant cooler cool for:

[0018] P cool (T cool )=P rad (T cool )-P atm (T amb )-P sun -P cond+conv ①;

[0019] Where P cool (T cool ) is the net cooling power of the radiant cooler, P rad (T cool ) is the energy radiated by the radiant cooler, P atm (T amb ) is the power absorbed by the incident atmospheric thermal radiation, P sun is the incident solar energy absorbed by the radiative cooler, P cond+conv for energy lost due to convection and conduction;

[0020] The power radiated by the radiant cooler is P rad for:

[0021]

[0022] Where A is the film area, the radiation angle θ, the wavelength λ, the spectrum and angular emissivity of the radiation cooler are ∈(λ,θ), and the angular integral over the hemisphere is ∫dΩ=2π∫0 π / 2 dθsinθ. Spectral radiation of a black body at temperature T where h is Planck's constant, k B is the Boltzmann constant, c is the speed of light, and λ is the wavelength of the incident light;

[0023] The absorbed power P caused by incident atmospheric thermal radiation atm for:

[0024]

[0025] where the angular emissivity of the atmosphere is given by ∈ atm (λ,θ)=1-t(λ) 1-cosθ We get, where t(λ) is the atmospheric transmittance in the zenith direction;

[0026] The incident solar energy P absorbed by the structure sun for:

[0027]

[0028] In the formula, the solar illumination is calculated using the AM1.5 spectrum I AM1.5 (λ) indicates;

[0029] Using Kirchhoff's radiation law, replace the absorptivity of the structure with the emissivity ∈(λ,θ), and we can get formulas ③ and ④;

[0030] Power loss due to convection and conduction P cond+conv for:

[0031] P cond+conv (T cool ,T amb )=Ah c (T amb -T cool ) ⑤;

[0032] h c =h cond +h conv is a combined non-radiative thermal coefficient that captures the collective effect of conduction and convection heating due to the contact of the radiant cooler with the external surfaces and the air adjacent to the radiant cooler;

[0033] Pcool(T cool =T amb ) defines the cooling power at ambient air temperature. In the absence of net outflow, the temperature of the radiant cooler should reach a stable state below the ambient temperature. When Pcool(T) = 0 in formula ①, the solution T cool Defined as the steady-state temperature T s ;

[0034] The cooling effect is expressed by the temperature difference ΔT = T amb -T cool It is shown that from the above formulas ①-⑤, when the radiation cooler measures the temperature difference ΔT, and the ambient temperature T amb It is known that the steady-state temperature T of the radiation cooler can be obtained s ; From Pcool(Ts)=0, we can know the relationship between Pcool and Ts;

[0035] The relationship between the temperature difference of the transmitter and the cooling power is: ΔT = f1(P cool )⑥;

[0036] The relationship between cooling power and radiation angle is: P cool =f2(θ)⑦;

[0037] The corresponding relationship between radiation angle and depth is:

[0038] In the formula, θ is the radiation angle, r is the distance from the radiation cooler to the well wall;

[0039] It can be concluded that: through the temperature difference ΔT or cooling power P cool The depth value can be obtained;

[0040] Therefore, the well depth can be measured based on the principle of radiation cooler, and depth measurement can be performed even in a dark environment.

[0041] The beneficial effects of the present invention are as follows: the present invention adds a mass layer below the reflective layer, which serves to stabilize the radiation cooler and control the error caused by its swinging in the up and down process; the use of a mass layer with a certain weight can improve the measurement accuracy and improve the measurement efficiency; it solves the shortcomings of existing depth measuring instruments such as reduced work efficiency and large errors due to the influence of the environment during the depth measuring process.

[0042] The present invention can use a special rope that combines a rope and a thermocouple wire in one, thereby reducing measurement errors and improving measurement accuracy, and at the same time reducing the overall mass of the radiation cooler depth sounding device to a certain extent; it solves the problem that a large number of errors will be generated due to the stretching, wear and bending of conventional ropes due to the increase in the number of measurements, which greatly affects the measurement accuracy;

[0043] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given in detail as follows in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 This is a schematic diagram of the structure of a device for measuring well depth based on the principle of radiation cooling;

[0046] Figure 2 is a schematic diagram of the cross section of a radiation cooler;

[0047] Figure 3 This is a schematic diagram of the structure of the embodiment of the present invention after being illuminated;

[0048] Figure 4 This is a schematic diagram of the structure of the well logging embodiment of the present invention;

[0049] Figure 5 The relationship curve between temperature difference and well depth during well logging in an embodiment of the present invention;

[0050] The figure marks of the above figures are: 01-air layer, 02-emitting layer, 03-reflecting layer, 04-packaging film, 05-first thermocouple, 06-second thermocouple, 07-sky, 08-well device, 09-wellhead, 10-rope, 11-well wall, 12-depth to be measured, 13-radiation angle, 14-radiation cooler, 15-bottom of the well. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] See attached Figure 1 , 2The reflective layer 03 selects an aluminum plate as the substrate of the radiation cooler to highly reflect sunlight. The emission layer 02 on the reflective layer 03 is a planar polydimethylsiloxane film (PDMS) with an area of ​​A=1㎡ and a thickness of 150μm; above the emission layer is a certain thickness of air 01; a second thermocouple 06 is placed between the reflective layer and the emission layer; a first thermocouple 05 is placed between the emission layer and the air layer; the first thermocouple and the second thermocouple are both K-type thermocouples with an accuracy of 0.1℃ and a measurement range of -50-200℃; finally, the device is packaged with a packaging film 04 to form an integrated radiation cooler of air-PDMS-substrate;

[0053] See attached Figure 4 , there is air without clouds or buildings between the sky 07 and the wellhead 09, the wellhead 09 is a circle with a radius of r=10m, the wellhead device 08 is connected to the radiation cooler 14 through the rope 10, and controls the position of the radiation cooler device falling from the middle of the wellhead; when the radiation cooler is at different depths of the well wall 11, the radiation angle 13 also changes, resulting in different cooling effects of the radiation cooler; the vertical distance from the horizontal position of the device to the wellhead 09 is the depth to be measured 12; the maximum detection depth does not exceed the bottom of the well 15, when the radiation cooler contacts the bottom of the well, the cooling effect of the radiation cooler no longer changes, and the depth value measured at this time is the maximum measurement value.

[0054] When the ambient temperature is 20℃ and the wavelength of sunlight is set at 0.3-19μm, Matlab software is first used to calculate the emissivity of the PDMS film at different wavelengths and angles of the structure, with a wavelength interval of 10nm and an angle interval of 5°. Then, the difference function is used in Mathematica to simulate the emissivity of the 0.3-19nm band as it changes with angle.

[0055] The cooling effect is expressed by the temperature difference ΔT = T amb -T cool It indicates that the cooling power is calculated by Mathematica simulation when Tcool = Tamb. The net cooling power of the radiation refrigerator is:

[0056] P cool (T amb )=P rad (T amb )-P atm (T amb )-P sun -P cond+conv ⑨;

[0057] The power radiated by the radiation cooler is:

[0058]

[0059] Where A is the film area of ​​1m 2 , the radiation angle θ ranges from 0 to 90°, and the wavelength λ ranges from 0.3 to 19 μm;

[0060] Absorbed power due to incident atmospheric thermal radiation:

[0061] P atm (T) = A∫dΩcosθ∫0 ∞ dλI BB (T,λ)∈(λ,θ)∈ atm (λ,θ)

[0062] Here, it is assumed that the atmospheric temperature is equal to the ambient temperature, that is, T atm =T amb :

[0063]

[0064] Incident solar energy absorbed by the structure Here P sun =0, that is, radiative cooling when the illuminance is 0;

[0065] Power loss due to convection and conduction P cond+conv (T cool ,T amb )=Ah c (T amb -T cool ), take hc=6.9;

[0066] The final formula for calculating cooling power is P cool (T) = P rad (T)-P atm (T amb )-P cond+conv , the surface cooling power P is usually cool (T), the net power outflow from the surface as a function of its temperature;

[0067] By resolving P cool (T cool )=0, solve for the steady-state temperature T s , which is the temperature of the radiation cooler; through this P cool The linear relationship between (T) and the radiation angle θ shows that the radiation angle θ at this position is

[0068] When the radiation angle 13 is within (0,90°), the temperature difference and cooling power are linearly related; the radius of the wellhead 09 is 10m, and the tangent formula The measured depth value is calculated.

[0069] Attached Figure 5The curve relationship between temperature difference and well depth is shown in the figure. It can be seen from the figure that the temperature difference of the radiation effect can be combined with formula ①- The depth value of the radiation cooler is obtained. Therefore, the present invention can measure the depth value through the temperature difference.

[0070] The device for measuring the well depth based on the radiation cooling principle of this scheme can avoid the "error of stretching length". The device is independent of the auxiliary device and is only related to the "actual location"; the device for measuring the well depth based on the radiation cooling principle adopts passive cooling technology and can measure without active power supply; the device for measuring the well depth based on the radiation cooling principle does not require contact return measurement and does not need to contact with the object, and the depth at any position can be measured at this time; the device for measuring the well depth based on the radiation cooling principle can realize measurement in a night environment, is not restricted by the night environment, and does not affect the measurement during the day.

Claims

1. A device for measuring well depth based on the principle of radiation cooling, characterized in that: The device includes, in sequence along the sky direction, an anti-flow air layer (01), an emission layer (02) of a radiation cooling material, and a reflection layer (03) with a high reflectivity of sunlight, wherein the anti-flow air layer (01) is used to prevent moisture in the well and flowing air from affecting the measurement results of the device; A second thermocouple is placed between the reflective layer and the emitting layer; A first thermocouple is placed between the emission layer and the air layer; The first thermocouple and the second thermocouple are both K-type thermocouples; Encapsulating with encapsulation film to form an integral radiation refrigerator; The emission layer (02) of the radiation cooling material is used to radiate heat to outer space through a transparent window of 8 to 13 μm in the atmosphere; The reflective layer (03) with high sunlight reflectivity is used to reflect more than 90% of sunlight and reduce heat absorption; When the radiation cooler is at different depths, the radiation angle also changes, resulting in different cooling effects of the radiation cooler. The vertical distance from the horizontal position of the device to the wellhead is the depth to be measured. The corresponding relationship between the radiation angle θ and the depth to be measured is: The measurement result of the second thermocouple is the temperature Tcool of the radiation cooler, the measurement result of the first thermocouple is Tamb, and the difference between the measurement results of the first thermocouple and the second thermocouple is the temperature difference ΔT=Tamb-Tcool; The relationship between the cooling power Pcool and the radiation angle θ is: Pcool=f2(θ) The measured depth value can be obtained through the temperature difference ΔT or the cooling power Pcool.

2. The device for measuring well depth based on the radiation cooling principle according to claim 1, characterized in that: The reflective layer (03) uses a metal reflective mirror or a plane reflective mirror including a reflective film layer.

3. The device for measuring well depth based on the radiation cooling principle according to claim 1, characterized in that: The emission layer (02) uses radiation cooling material.

4. The device for measuring well depth based on the radiation cooling principle according to claim 1, characterized in that: The emission layer (02) is located above the reflection layer (03), and the emission layer (02) is located in the plane of the reflection layer (03).

5. The device for measuring well depth based on the radiation cooling principle according to claim 1, characterized in that: The working wavelength of the device is 0.3-19 μm.

6. A method for measuring well depth based on the principle of radiation cooling, specifically: Step 1: placing a second thermocouple (06) between the reflective layer (03) and the emitting layer (02); Step 2: placing a first thermocouple (05) between the emission layer (02) and the air layer (01); Step 3: The measurement result of the second thermocouple (06) between the reflective layer (03) and the emitting layer (02) is the radiation cooler temperature Tcool, the measurement result of the first thermocouple between the emitting layer and the air layer is Tamb, and the difference in the measurement results is the temperature difference ΔT=Tamb-Tcool; finally, the windshield is formed by packaging with a packaging film; The temperature reduction of the radiant cooler satisfies the following relationship: When a radiation cooler with an area of ​​A is exposed to sunlight, it is subject to solar irradiance and atmospheric thermal radiation. The net cooling power Pcool of the radiation cooler is: Pcool(Tcool)=Prad(Tcool)-Patm(Tamb)-Psun-Pcond+conv①; Where Pcool(Tcool) is the net cooling power of the radiant cooler, Prad(Tcool) is the energy radiated by the radiant cooler, Patm(Tamb) is the power absorbed by the incident atmospheric thermal radiation, Psun is the incident solar energy absorbed by the radiant cooler, and Pcond+conv is the energy lost due to convection and conduction. The power Prad radiated by the radiation cooler is: Where A is the film area, the radiation angle θ, the wavelength λ, the spectrum and angular emissivity of the radiation cooler are ∈(λ,θ), and the angular integral over the hemisphere is ∫dΩ=2π∫0 π / 2 dθsinθ; spectral radiation of a black body at temperature T where h is Planck's constant, k B is the Boltzmann constant, c is the speed of light, and λ is the wavelength of the incident light; The absorbed power Patm caused by the incident atmospheric thermal radiation is: where the angular emissivity of the atmosphere is given by ∈atm(λ,θ)=1-t(λ) 1 -cosθ, where t(λ) is the atmospheric transmittance in the zenith direction; The incident solar energy Psun absorbed by the structure is: In the formula, the solar illumination is calculated using the AM1.5 spectrum I AM1.5 (λ) indicates; Using Kirchhoff's radiation law, replace the absorptivity of the structure with the emissivity ∈(λ,θ), and we can get formulas ③ and ④; The power loss caused by convection and conduction Pcond+conv is: Pcond+conv(Tcool,Tamb)=Ahc(Tamb-Tcool)⑤; hc = hcond + hconv is a combined non-radiative thermal coefficient that captures the collective effect of conduction and convection heating due to the contact of the radiant cooler with the external surface and the air adjacent to the radiant cooler; Pcool (Tcool = Tamb) defines the cooling power at ambient air temperature. In the absence of net outflow, the temperature of the radiant cooler should reach a steady state below the ambient temperature. When Pcool (T) = 0 in formula ①, the solution Tcool is defined as the steady-state temperature Ts. The cooling effect is expressed by temperature difference ΔT = Tamb-Tcool. From the above formulas ①-⑤, it can be seen that when the radiation cooler measures the temperature difference ΔT and the ambient temperature Tamb is known, the steady-state temperature Ts of the radiation cooler can be obtained; From Pcool(Ts)=0, we can know the relationship between Pcool and Ts; The relationship between the temperature difference of the transmitter and the cooling power is: ΔT = f1 (Pcool); The relationship between cooling power and radiation angle is: Pcool = f2(θ); The corresponding relationship between radiation angle and depth is: The depth value can be obtained through the temperature difference ΔT or the cooling power Pcool.

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