PERMAFROST THAWING PREVENTION VIA A COOLING GEOTEXTILE

Abstract

Permafrost thawing prevention may involve deploying a cooling geotextile onto a permafrost soil. The geotextile may include a biomass scaffold comprising natural plant-based fibers. The geotextile may further include a cellulose layer comprising cellulose fibers laminated onto the biomass scaffold such that the cellulose fibers are physically entangled with the plant-based fibers. The geotextile may further include a hydrophobic and biodegradable coating which defines at least one surface of the geotextile. The geotextile may be optically opaque, exhibits high solar reflectivity, and maintains high mid-infrared emissivity to enable passive radiative cooling.

Claims

1. A cooling geotextile, comprising: a biomass scaffold comprising natural plant-based fibers; a cellulose layer comprising cellulose fibers laminated onto the biomass scaffold such that the cellulose fibers are physically entangled with the plant-based fibers; and a hydrophobic and biodegradable coating which defines at least one surface of the geotextile, wherein the geotextile is optically opaque, exhibits high solar reflectivity, and maintains high mid-infrared emissivity to enable passive radiative cooling.

2. The cooling geotextile of claim 1, wherein the hydrophobic and biodegradable coating comprises cellulose acetate (CA).

3. The cooling geotextile of claim 1, wherein the hydrophobic and biodegradable coating may include polydimethylsiloxane (PDMS), silica (SiO.sub.2), or a combination thereof.

4. The cooling geotextile of claim 1, wherein the coating or treatment forms a conformal or porous layer that retains breathability and transparency to mid-infrared radiation.

5. The cooling geotextile of claim 1, wherein the geotextile has a solar reflectance of at least 90% across the wavelength range of 250 nm to 2500 nm and an emissivity of at least 0.90 in the mid-infrared range of 8 to 13 m.

6. The cooling geotextile of claim 1, wherein the cellulose layer is optically opaque and contributes to both solar reflection and mid-infrared emission.

7. The cooling geotextile of claim 1, wherein the natural plant-based fibers include cotton, jute, hemp, flax, or a combination thereof.

8. The cooling geotextile of claim 1, wherein the cellulose layer is formed from carded and webbed fibers including cotton, flax, hemp, or a combination thereof.

9. A method of fabricating a cooling geotextile, comprising: forming a biomass scaffold from natural plant-based fibers; layering a cellulose sheet on the biomass scaffold and mechanically entangling fibers of the cellulose sheet with fibers to the biomass scaffold to form a composite sheet; and applying a hydrophobic and biodegradable coating to at least one surface of the composite sheet, wherein the coating or treatment enhances solar reflectivity and preserves mid-infrared emissivity.

10. The method of claim 9, wherein applying a hydrophobic and biodegradable coating to at least one surface of the composite sheet further comprises: preparing a cellulose acetate (CA) solution; applying the cellulose acetate solution to the composite by spray coating, dip coating, or blade coating; and drying the coated composite to form the hydrophobic and biodegradable layer which maintains high solar reflectivity and mid-infrared emissivity.

11. A method comprising: deploying onto a permafrost soil, a geotextile comprising a biomass scaffold comprising natural plant-based fibers, a cellulose layer comprising cellulose fibers laminated onto the biomass scaffold such that the cellulose fibers are physically entangled with the plant-based fibers, a hydrophobic and biodegradable coating which defines at least one surface of the geotextile.

12. The method of claim 11, wherein the geotextile is optically opaque, exhibits high solar reflectivity, and maintains high mid-infrared emissivity to enable passive radiative cooling.

13. The method of claim 11, wherein the hydrophobic and biodegradable coating comprises cellulose acetate (CA).

14. The method of claim 11, wherein the hydrophobic and biodegradable coating may include cellulose acetate (CA), polydimethylsiloxane (PDMS), silica (SiO.sub.2), or a combination thereof.

15. The method of claim 11, wherein the coating or treatment forms a conformal or porous layer that retains breathability and transparency to mid-infrared radiation.

16. The method of claim 11, wherein the geotextile has a solar reflectance of at least 90% across the wavelength range of 250 nm to 2500 nm and an emissivity of at least 0.90 in the mid-infrared range of 8 to 13 m.

17. The method of claim 11, wherein the cellulose layer is optically opaque and contributes to both solar reflection and mid-infrared emission.

18. The method of claim 11, wherein the natural plant-based fibers include cotton, jute, hemp, flax, or a combination thereof.

19. The method of claim 11, wherein the cellulose layer is formed from carded and webbed fibers including cotton, flax, hemp, or a combination thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The embodiments may be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale. Moreover, in the figures, like-referenced numerals designate corresponding parts throughout the different views.

[0005] FIG. 1 illustrates an example of a cooling geotextile.

[0006] FIG. 2 illustrates a method of manufacturing a cooling geotextile.

[0007] FIG. 3A-C illustrates a third example of the cooling geotextile during varies stages of manufacture.

[0008] FIG. 4A-C illustrate a Scanning Electron Microscopy (SEM) images of the cooling geotextile during various stages of manufacture.

[0009] FIG. 5A-B illustrate an SEM image of micro-and nanoscale porous structure of cellulose acetate (CA) after solvent quenching and pore size distribution analysis of cooling geotextile with/without solvent quenching and untreated nonwoven cotton fiber layer.

DETAILED DESCRIPTION

[0010] Extensive investigations focus on alleviating these challenges with two main strategies: heat rejection and heat extraction. Heat rejection method aims to reduce or even diminish the heat transfer from air and sun toward the permafrost via shading or insulating. For instance, the injection of sulfate aerosols into the stratosphere has been proposed to increase Earth's albedo for reducing the Arctic temperature. Urea insulation foam (thermal conductivity, 0.029 W.Math.m.sup.1.Math.K.sup.1) has been frequently employed underneath infrastructures to prevent direct heat conduction to the soil. However, extensive urea usage on the soil surface could induce NH.sub.3 volatilization, NO.sub.2 accumulation, and phytotoxicity issues. Heat extraction strategies such as ventilation, refrigeration, and thermosyphon, dissipate heat from the soil either actively or passively to cool the permafrost. Specifically, the widely used thermosyphon tubes transfer heat from the permafrost layer to the environment by the evaporation and condensation cycle of a pressurized liquid. However, thermosyphon's complex design, high maintenance, and installation cost, and potential environmental impact (resulting from the leaking of working fluid) restrict its large-scale applications in the fragile Arctic ecosystem. Recently, radiative cooling has been applied for ice protection; however, exposed ground in the Arctic summer necessitates a focus on land cooling and stabilization. Challenges arising from permafrost thawing, including soil erosion and landscape collapse, inherently underscore the imperative for robust and resilient geotextile materials. White paint has been used to increase the ground albedo; nevertheless, the organic binder (such as Alkyd binders in paints) may release toxic compounds to the vulnerable Arctic ecosystem. Moreover, strong winds (25 m.Math.s1) and yearly freeze-thaw cycles (37 C. to 24 C. at Utqiagvik, Alaska, in 2023) require mechanically robust and thermally stable materials. Hence, it is imperative to develop easy-to-retrofit, reliable, and sustainable approaches to save thawing permafrost in a cost-effective and eco-friendly deployment manner.

[0011] In this work, we demonstrate a scalable and biodegradable cooling geotextile to protect the thawing permafrost by three key mechanisms: increasing the ground albedo, facilitating passive cooling, and enhancing thermal insulation. Importantly, all components of the cooling geotextile are derived from biomass, making them biodegradable with minimized ecological impact. Moreover, from macroscopic woven patterns of fabrics down to nanofibrils and nanopores, the cooling geotextile is hierarchically engineered to withstand the Arctic harsh weather, such as strong winds and periodic freeze-thaw cycles, by anchored onto the soil to effectively reduce ground temperature and control erosion. It rejects 96.3% solar irradiance due to the strong sunlight backscattering of micro-and nano-sized pores within the coating layer, which surpasses the performance of most natural materials like fresh snow (typically 80-90%).

[0012] Remarkably, without external energy input or moving parts, the cooling geotextile spontaneously cools itself by emitting thermal radiation to outer space through the atmospheric window (8-13 um). Its low thermal conductivity is also an excellent thermal barrier, protecting permafrost from temperature rising in Arctic summer. Based on a comparative analysis with foam insulation and thermosyphon examples from current thermal insulation and extraction strategies, the cooling geotextile is the most suitable solution for preventing permafrost thawing. Notably, it offers a cost advantage, with low fabrication costs of $3.38 m.sup.2 and $4.57 m.sup.2 for the cotton-based and jute-based cooling geotextiles, and a roll-to-roll manufacturing approach. We envision that this cooling geotextile can be retrofitted to cover vast low-albedo Arctic areas, including bare ground and shorelines, and effectively mitigate the escalating permafrost thawing during Arctic summer. Additionally, for infrastructure protection, this rollable and lightweight (0.8 kg.Math.m.sup.2) cooling geotextile can be deployed in the vicinity of residential regions to safeguard land subsidence.

[0013] FIG. 1 illustrates an example of a cooling geotextile 100. The cooling geotextile 100 may be a sheet packaged in a roll. The sheet may include a biomass scaffold 102, a cellulose layer 104 having cellulose fibers which are physically intertwined with the biomass scaffold, and a hydrophobic material which defines at least one surface of the geotextile,

[0014] The resultant geotextile may be optically opaque, exhibits high solar reflectivity, and maintains high mid-infrared emissivity to enable passive radiative cooling. For example, The hydrophobic layer, together with the underlying cellulose layer, forms a surface that is highly reflective across the spectrum of 250 to 2500 nm and highly emissive in the infrared (especially 8 to 13 um). The surface may geotextile have a solar reflectance of at least 90% across the wavelength range of 250 nm to 2500 nm and an emissivity of at least 0.90 in the mid-infrared range of 8 to 13 m.

[0015] Accordingly to various examples described herein, the biomass may include a biomass scaffold may include a woven or nonwoven fibers. In some examples, the biomass scaffold may include natural plant-based fibers including cotton, jute, hemp, flax, or a combination thereof.

[0016] The cellulose layer may be formed from carded and/or webbed fibers. In some examples, the cellulose layer may include cotton, flax, hemp, or other renewable biomass sources.

[0017] The hydrophobic material may be applied as a coating or treatment to the combined cellulose and biomass scaffold. The hydrophobic material may also be biodegradable. The hydrophobic material may form at least one outer surface of the cooling geotextile. For example, the hydrophobic material may provide a conform to the outer surface of the geotextile. The hydrophobic material may include a porous layer that retains breathability and transparency to mid-infrared radiation. By way of example, the hydrophobic material may include cellulose acetate (CA), polydimethylsiloxane (PDMS), silica (SiO.sub.2), or a combination thereof.

[0018] FIG. 2 illustrates a method of manufacturing the cooling geotextile. The manufacturing may include forming a biomass scaffold. The biomass scaffold in may be constructed using natural plant-derived fibers, such as those extracted from bamboo, hemp, jute, cotton, corn stalks, or other lignocellulosic sources. These fibers are processed into either a woven or nonwoven structure. In woven scaffolds, the fibers are spun into yarns and interlaced in orthogonal patterns to provide mechanical robustness and breathability. In nonwoven scaffolds, the fibers are deposited onto a flat surface and bonded through methods such as needle-punching which mechanically entangles the fibers.

[0019] Throughout the formation process, the porosity and flexibility of the scaffold are preserved to enable efficient water vapor transport and ensure mechanical conformity to the underlying soil or infrastructure. The resulting scaffold retains the natural biodegradability of the source material while providing the structural integrity necessary to support the additional functional layers of the cooling geotextile.

[0020] The manufacturing further include layering a cellulose sheet on top of the biomass scaffold and mechanically entangling the fibers of the cellulose sheet with those of the underlying scaffold to form a cohesive composite sheet. This mechanical entanglement can be achieved through needle-punching, a process in which barbed needles repeatedly penetrate the layered structure. As the needles enter and withdraw, the barbs catch cellulose fibers from the upper sheet and drive them into the biomass scaffold, while simultaneously drawing scaffold fibers upward into the cellulose layer. This action interlocks the two layers at multiple contact points, creating a physically bonded interface without the need for chemical adhesives.

[0021] The manufacturing may further include applying a hydrophobic and biodegradable material to at least one surface of the composite sheet. The hydrophobic and biodegradable material may be applied by coating or treatment. For example, A cellulose acetate (CA) solution may be prepared and then applied to the composite by spray coating, dip coating, or blade coating. Thereafter, the composite may be dried to form the hydrophobic and biodegradable layer which maintains high solar reflectivity and mid-infrared emissivity.

Examples and Validation

[0022] The following sections provide various non-limiting examples, experiments, and validation of the cooling geotextile described herein. FIG. 3A-C illustrates a third example of the cooling geotextile during varies stages of manufacture. FIG. 4A-C illustrate a Scanning Electron Microscopy (SEM) images of the cooling geotextile during various stages of manufacture. Cellulose, the most abundant natural polymer, constitutes approximately 90% of cotton fibers. Characterized by a theoretical modulus from 100-200 GPa and a tensile strength of 4.9-7.5 GPa in its crystalline form, cellulose has established itself as a promising material for engineering applications, especially under windy weather in extreme Arctic conditions. The cooling geotextile includes a robust woven biomass scaffold 302, a permeable and opaque nonwoven cotton fiber layer, and a high-albedo CA coating. As the scaffold of the cooling geotextile, the woven biomass scaffold with the modified topological weave pattern is fabricated using natural fibers, such as cotton and jute which are composed of aligned nanofibrils. A network of entangled cellulose fibers with a diameter of 13.5 m5.7m are then laminated onto the woven biomass scaffold without chemical binders. The jute and cellulose fibers intertwine and provide a matrix for hierarchically porous CA coating to bond. The CA coating, together with the nonwoven fiber layer, offers an albedo of 96.3%, resulting from broadband sunlight backscattering by the wide size distribution (from 50 nm to 2,500 nm) of its hierarchical porous structures during the solvent quenching process. The physical entanglement of these three components from the nanoscale, microscale, to macroscope, along with intrinsic hydrogen bonding between CA and cellulose, contribute to the cooling geotextile's exceptional mechanical strength.

[0023] The ability to upscale fabrication cost-effectively is a prerequisite to protecting the thawing Arctic permafrost. A 100 m long and 1.0 m wide laminated scaffold composed of woven jute scaffold and a nonwoven cotton fiber layer has been manufactured. Uniform arrays of punching needles are applied to entangle and bind the woven and nonwoven fiber layers together, producing a robust laminated jute scaffold.

[0024] For large scale deployment, the low unit cost ($3.38 m2 for the cotton-based cooling geotextile and $4.57 m2 for the jute-based cooling geotextile) and low carbon footprint (0.7 kg-m2) make it a cost-effective and environmentally sustainable alternative for geoengineering applications in vulnerable permafrost regions. Moreover, life cycle analysis indicates that the cooling geotextile has a reduced impact on climate change and fossil depletion, as well as minimizing the use of chemicals and energy, compared to the conventional polyurea foam.

[0025] Given the extreme coldness reported (which can drop below 50 C. in Alaska), the freeze-thaw cycles of bare ground, the melting of ice and snow, and sharp rocks in the Arctic region, the need for a mechanically robust approach to mitigate the permafrost thawing and reinforce coastline cannot be overstated. Additionally, ice and snow melting during the Arctic summer can result in flooding and erosion, thereby necessitating a requirement of high water permittivity. The cooling geotextile described herein is qualified and even exceeds the mechanical strength and permittivity requirement of geotextile according to the NEH requirements (shown in Table 1) because of the hierarchically physical entanglement at different scales and hydrogen bonding between CA and cellulose.

TABLE-US-00001 TABLE 1 Mechanical strength and permittivity requirements for the geotextile Properties The US NEH Requirements Grab Tensile Strength 113 kg for 100 mm 200 mm Ultimate Tear Force 50.8 kg for 75 mm 200 mm Ultimate Puncture Force 40.8 kg for samples with a 45 mm diameter and a puncture probe with a diameter of 8 mm Permittivity 0.5 s for samples with 50 mm diameter

[0026] While the NEH requires at least 112 kg tensile strength, the cotton-based and jute-based cooling geotextiles exhibited higher tensile strengths of 1,029 kg and 1,682 kg, respectively. The tensile strains at the point of failure for cotton-based and jute-based cooling geotextiles both fall below 50%, meeting the criteria outlined in the NEH. The trapezoidal tear strengths of the cotton-based and jute-based cooling geotextiles are 149 kg and 191 kg, respectively, which far exceed the NEH requirement of 50.8 kg. Moreover, the cotton-based and jute-based cooling geotextile can withstand 56.5 kg and 61 kg puncture strength, respectively, which meets the NEH puncture strength requirement of 40.8 kg. This enables its mechanical robustness against sharp surfaces of rocks, roots, sticks or other debris and trampling by wildlife in the Arctic. In addition, the tensile strength of the cooling geotextile retains over 95% after undergoing freeze-thaw cycles, demonstrating good durability in humid and cold climates. Notably, even when subjected to vehicular load, the cooling geotextile remains fully intact with no observable compromise to its structural integrity. The water permittivity of the cotton-based cooling geotextile is 0.0177 seconds, indicating that water can flow through 28 times faster than the NEH permittivity requirement of 0.5 seconds to prevent flooding formation.

[0027] Apart from its superior mechanical robustness, the cooling geotextile is inherently biodegradable, which reduces the overall cost and protects the sensitive Arctic ecosystem. After 6 weeks in the soil and compost mixture with a weight ratio of 1:1 and a water content of 10-50% at 20 C., the cooling geotextile exhibited a weight loss of over 50 wt %, demonstrating the biodegradability of each component in the cooling geotextile. It's important to highlight that the colder average temperatures in the Arctic environment reduce microorganism activity in biodegradation and applying the cooling geotextile on top of the soil limits interactions with subsurface microorganisms. As a result, when our cooling geotextile is deployed directly on the bare ground, its service life will remain unaffected. Moreover, the white geotextile is also flexible and rollable for quick deployment. Overall, the mechanically robust cooling geotextile stems from its hierarchical structure and woven pattern of biomass scaffold, i.e., jute or cotton fabrics.

[0028] Other than the hierarchically porous structure of the nonwoven cotton fiber layers that enables strong adhesion between the CA coating layer and the cellulose cotton fibers, down to the atomic level, cellulose has strong hydrogen bonding between its molecular chains due to the presence of hydroxyl groups in its glucose monomers. The CA applied to the cooling geotextile has a degree of substitution (DS) of 2.5, meaning that five hydroxyl groups are substituted by the acetyl groups. It shows that the model of investigating interactions at CA and cotton cellulose interface focusing on the acetyl groups, while the red arrow indicates the displacement direction. It exhibits that the CA and cotton cellulose can form 255 hydrogen bonds at a 105 nm2 interface. The interfacial energy is 1,650 Kcal.Math.mol1 and decreases as the CA is pulled out from the CA and cotton cellulose interface. The right-bottom part of FIG. 2K shows the model for non-equilibrium molecular dynamics, analyzing the mechanical properties of CA and cotton cellulose chains under compression and tension loading in a vertical direction. The CA and cotton cellulose chains indicate a tensile strength of 210 MPa and a compressive strength of 280 MPa, respectively. As suggested by the atomic-level interaction of CA and cotton cellulose chains, mechanical entanglement among the CA coating layer, nonwoven cotton fibers, and woven pattern of biomass scaffold, the cooling geotextile offers a higher grab tensile strength (970 kg) compared to the original woven cotton scaffold (938 kg) and the laminated cotton scaffold (953 kg).

[0029] Albedo engineering via compositional and structural modifications for heat rejection: Solar radiation is one of the major thermal loads of permafrost thawing in low-albedo regions where the ground surface substantially absorbs solar radiation, warming the active layer and transferring heat to the permafrost layer beneath. Amongst the natural substances with different albedo in the Arctic, fresh snow features the highest albedo value to effectively reflect solar radiation, reducing the heating effect on the soil underneath. However, during the Arctic summer, diminished snow cover exposes low-albedo bare ground, substantially increasing the absorption of solar energy.

[0030] FIG. 5A-B illustrate an SEM image of micro-and nanoscale porousstructure of CA after solvent quenching and pore size distribution analysis of cooling geotextile with/without solvent quenching and untreated nonwoven cotton fiber layer. Cellulose features a low absorption in the solar range, however, pristine woven cotton scaffold and laminated cotton scaffold show solar reflectance of 72.2% and 82.6% owing to the presence of other substances such as waxes, protein, and pectin, as well as the large pores inside (up to 100 m). Additionally, due to the loosely entangled cellulose microfibers, the nonwoven cotton fiber layer (600 m) exhibits a solar transmittance of 17%, resulting in a solar reflection of 76%. The solvent quenching process in the CA coating layer significantly increases the submicron pores and yields a wider pore size distribution from 50 nm to 2,500 nm, as indicated by the SEM image (FIG. 5A) and mercury intrusion porosimetry (MIP) analysis (FIG. 5B), compared with that of nonwoven fabrics (1 m to 10 m). The size and distribution of those pores can be tuned by varying the solvent choices, CA concentration, and drying conditions to optimize its albedo. Moreover, CA is produced by modifying cellulose through acetylation, in which acetyl groups are added to the cellulose molecule. These introduced acetate groups decrease the crystallinity of cellulose and reduce the propensity to photooxidation, providing CA with a lower absorption over UV and visible wavelengths compared with cellulose.

[0031] Therefore, as an effective backscattering medium of sunlight, those hierarchical pores of the CA coating layer can significantly enhance the solar reflectance of the cooling geotextile. A maximized albedo of 96.3% of cooling geotextiles was achieved by a relatively low thickness of 100 m CA coating on top of the nonwoven fiber layer. This thickness is much thinner than other radiative cooling films (>500 m) fabricated by the solvent quenching method.

[0032] To explain the underlying mechanism, a finite-difference time-domain (FDTD) method was employed to reflectance spectra of the modeled porous cooling geotextile. It illustrates that nanopores (100 nm, 200 nm, and 500 nm in diameter) effectively reflect visible sunlight, while those micro-sized pores with diameters of 1000nm, 2000 nm, and 4000 nm show excellent good reflection performance in the NIR wavelengths. Moreover, the simulation of scattering efficiency shows that the nanopores from 100 to 500 nm can strongly scatter UV and visible wavelengths, while micro-sized pores from 2000 nm or 4000 nm can effectively scatter the NIR wavelengths. The simulated CA film yields low absorption in the solar range, which correlates to the experimentally measured solar absorption of 2%.

[0033] Simulation results show that the dense CA film exhibits a visible reflectance of 8%, while the porous CA film with different pore distributions exhibits various reflectance spectra. For instance, a CA film with 500 nm pores has a broadband reflectance (>60%) over both visible and near-infrared (NIR) ranges, while its reflectance decreases as the pore size increases from 1000 nm to 4000 nm. Considering that the pore size distribution of cooling geotextile lies from 100 nm to 4000 nm induced by the solvent quenching process, its high solar reflectance mainly results from the randomly porous CA coating layer. Taking advantage of the low solar absorption and high diffuse reflection of the CA layer, the cooling geotextile possesses a high solar reflectance of 96.3% from 250 nm to 2000 nm. In contrast, the soil samples display a low solar reflectance of 16-29% due to their elevated ratio of the absorption coefficient and scattering coefficient. Soil albedo is highly dependent on its water content. To better understand solar heating effects in the Arctic environments, the soil heating power is estimated for soils with different water contents. Under AM 1.5 solar irradiance, the solar heating power increases from 600 to 750 W.Math.m2 when the water content rises from 0 to 75 wt %. This suggests that the soil with higher water content tends to absorb more solar energy to heat the permafrost layer during summer.

[0034] Considering that the Arctic summer radiation is lower than the AM 1.5 solar irradiance, the Arctic soil heating power is scaled to 279-546 W.Math.m2. After being covered by our cooling geotextile, the surface albedo will be significantly increased, as shown by the comparative albedo analysis of different Arctic natural substances. Among these natural substances on ground level, Arctic vegetation (8-32%), soil (10-30%), and ice (30-40%) all have a relatively low albedo. Their solar reflectance fluctuates widely for different species and different seasons. Snow albedo reduces when impurities, including dust and sand, are introduced and varies for different seasons. As the cloud fraction and density decrease, fewer clouds are available to reflect sunlight. Consequently, more sunlight reaches the ground, leading to increased absorption, resulting in a reduction in the overall cloud albedo. Conversely, the cooling geotextile has a constant albedo of 96.3% without season changes to provide a reliable heat rejection effect. To visualize the heat rejection effect, four rolls of laminated scaffold (4 m wide) were placed over the soil for half an hour under direct sunlight, and a thermal image was taken to show the temperature distribution. The cooling geotextile was observed to be 15 C. cooler than the bare soil.

[0035] Soil cooling performance in field tests via heat rejection and heat extraction: The heat rejection capacity of the cooling geotextile is validated by its high albedo, which effectively minimizes solar absorption during the daytime by reflecting solar radiation. Another key feature of cooling geotextile is the high thermal emittance of 93% over the atmospheric window from 8 m to 13 m, allowing for efficient radiative heat dissipation to the cold outer space. This high thermal emittance stems from the strong molecular vibrations including OH, CO, CH, CO, and COC of CA and cellulose in cooling geotextile. Based on the measured thermal emittance spectra (2.5-20 m), the daytime cooling/heating powers of soil, cotton, and cooling geotextile are evaluated against standard AM 1.5 and Arctic solar irradiance, respectively. The daytime heating powers of soil are 407-609 W.Math.m-2 and 285-369 W.Math.m2 under AM 1.5 and Arctic summer conditions, respectively. On the contrary, the cooling geotextile exhibits a cooling effect, exemplified by a cooling power of 139 W.Math.m2 under AM 1.5 and 158 W.Math.m2 during the Arctic summer. Therefore, the surface of the cooling geotextile will be self-cooled below ambient temperature even in the Arctic summer, which can effectively cool the soil.

[0036] To further validate its viability, a one-dimensional heat transfer analysis is carried out to analyze the energy balance of bare soil and soil covered with cooling geotextile, considering both radiative cooling power and sensible heat. The one-dimensional energy balance analysis results demonstrate that the cooling geotextile significantly reduces the soil temperature.

[0037] Specifically, the soil covered with cooling geotextile is over 30 C. cooler than the bare soil and 8 C. cooler than the air temperature. These findings underscore the priority of employing the cooling geotextile as an efficient cooling solution for soil surfaces. Moreover, the micro-and nano-sized structures in cooling geotextile reduce the phonon pathways and impede air molecular movements during the heat transfer, resulting in a notably low thermal conductivity. This low thermal conductivity of cooling geotextile (0.028 W.Math.m1.Math.K1) renders it a thermal barrier between the ambient and soil, further reducing the temperature rise during the Arctic summer.

[0038] To experimentally demonstrate the performance of cooling geotextile, field tests were conducted to record the temperature response of the bare soil and soil covered by cooling geotextile at Purdue University, West Lafayette, IN (402521 N, 865512 W). Two insulation boxes with the same soil were wrapped in aluminum foil with one side facing the sky. One group was covered with cooling geotextile, while the other was only bare soil. A layer of polyethylene film that is transparent to solar and infrared wavelengths was employed as a windshield to reduce convective heat transfer. Temperature sensors were inserted in the soil at depths of 0, 20, and 40 cm, respectively, for temperature measurement

[0039] The average ambient temperature was 10 C. and the maximum solar intensity was 500 W.Math.m2 (Nov. 22nd to Nov. 23rd, 2022) since the average temperature and solar irradiation of the Arctic summer weather were around these values. The average temperature reduction during the daytime went 9.4 C. and 9.6 C. for these two days when soil was covered by a cooling geotextile. Because of the low albedo, the bar soil presented a quick temperature increase responding to the solar irradiation variations, yielding a considerably large temperature increment when the solar intensity increased from 200 to 500 W.Math.m2. Surface temperature rise also led to the quick temperature increase of soil at depths of 20 cm and 40 cm. In addition, field tests were conducted with the pre-frozen soil samples to mimic the permafrost thawing process in Arctic summer. The average ambient temperature was near 15 C., and the maximum solar intensity was 500 W.Math.m2 (from Nov. 18th to Nov. 19th, 2023). For the cooling-geotextile-covered soil, the average daytime temperature reductions reached 9 and 9.5 C. on these two days, respectively. Extensive warming phenomena have occurred in the Arctic region, where the daytime temperature could even exceed 20 C. in low-albedo areas. To investigate the cooling performance of the cooling geotextile at higher ambient temperatures, tests were conducted under daytime temperatures of 20 C. with a maximum solar intensity of 700 W.Math.m2, which is the maximum Arctic solar intensity. As the solar intensity peaks, the surface temperature of bare soil reached 55 C., which is 30 C. higher than that of cooling geotextile-covered soil bare soil (25 C.). From Oct. 1st to Oct. 4th, 2022, the cooling geotextile could cool the bare soil by 17 C. on average during the daytime. In addition, field tests were conducted with pre-frozen soil samples when the average ambient air temperature was near 20 C. on Sep. 29th, 2022. The bare soil surface shows a faster heating rate after exposure to solar radiation. The deeper layers of bare soil also warmed up more quickly than the cooling geotextile-covered soil, causing the temperature to rise from 2 C. to 17 C. quickly from 8 am to 10 am while the covered soil remained around 1 C. till 10 am. It was slowly heated up as the cooling geotextile effectively rejected the solar heating and ambient heat conduction when the ambient temperature was 20 C. because of the low thermal conductivity of 0.028 W.Math.m1.Math.K1 for the cooling geotextile. The cooling geotextile as a thermal insulation layer helps protect soil from thawing under high ambient temperatures. Consistent with theoretical calculations, cooling geotextile demonstrates enhanced soil cooling performances in field tests, showing the enormous potential for mitigating permafrost thawing. Evaporative cooling is another advantage of our cooling geotextile. Cellulose fiber layers have the property of absorbing water from either air or soil. Specifically, the cellulose fiber layer demonstrates the capacity to absorb a range of 1.2 to 10 wt % of water from air characterized by relative humidity levels spanning from 20% to 80%, as well as 20 to 29 wt % of water when it is placed over soil with a relative humidity ranging from 20% to 40%. Assuming deployment of the cooling geotextile over soil with a moisture content of 20 wt %, it has the potential to absorb approximately 20 wt % of water from the soil and subsequently release this moisture through evaporation into the atmosphere. This theoretical estimation of evaporative cooling power stands at 38-151 W.Math.m2 for cotton cellulose with a water content of 20 wt %.

[0040] To practically protect the thawing permafrost, considering the real scenario in the Arctic region, we use sandbags and wooden stakes to secure our cooling geotextile. 1 m spacing sandbags or wood stakes were used to anchor the cooling geotextile for soil reinforcement and landscape stabilization. This facile, cost-effective installation approach enables quick deployment to save urgent Arctic permafrost coastal erosion. Moreover, the cooling geotextile can anchor to uneven terrain, stabilizing coastal bluffs and maintaining a firm position amidst the robust Arctic winds. The air gap between the cooling geotextile and ground will be less than 2.2 cm under the average Arctic summer wind speeds (5-7 m.Math.s1) based on the air dynamic simulation. The cooling geotextile fortifies the underlying ground, enhancing the integrity and resilience of the coastal landscape. By facilitating heat rejection and radiative cooling, the cooling geotextile prevents overheating and crack formation resulting from permafrost thawing. Combining superior mechanical strength, durability, and potent cooling capabilities, the cooling geotextile emerges as an efficacious solution for protecting permafrost, combating coastal erosion, and stabilizing landscapes.

[0041] A second action may be said to be in response to a first action independent of whether the second action results directly or indirectly from the first action. The second action may occur at a substantially later time than the first action and still be in response to the first action. Similarly, the second action may be said to be in response to the first action even if intervening actions take place between the first action and the second action, and even if one or more of the intervening actions directly cause the second action to be performed. For example, a second action may be in response to a first action if the first action sets a flag and a third action later initiates the second action whenever the flag is set.

[0042] To clarify the use of and to hereby provide notice to the public, the phrases at least one of <A>, <B>, . . . and <N> or at least one of <A>, <B>, . . . <N>, or combinations thereof or <A>, <B>, . . . and/or <N> are defined by the Applicant in the broadest sense, superseding any other implied definitions hereinbefore or hereinafter unless expressly asserted by the Applicant to the contrary, to mean one or more elements selected from the group comprising A, B, . . . and N. In other words, the phrases mean any combination of one or more of the elements A, B, . . . or N including any one element alone or the one element in combination with one or more of the other elements which may also include, in combination, additional elements not listed.

[0043] While various embodiments have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible. Accordingly, the embodiments described herein are examples, not the only possible embodiments and implementations.