The increasing scarcity of freshwater resources has driven the rapid emergence of solar-driven interfacial evaporators(SDIEs)as a sustainable approach to harvest fresh water by utilizing solar energy.Lignocellulosic b...The increasing scarcity of freshwater resources has driven the rapid emergence of solar-driven interfacial evaporators(SDIEs)as a sustainable approach to harvest fresh water by utilizing solar energy.Lignocellulosic biomass,featuring natural abundance,excellent renewability,unique natural structures,and superior biodegradability compared to the synthetic polymers,is highly attractive for constructing solar steam generators.This review aims to offer an innovative and in-depth insight into designing and optimizing highperformance integrated solar interfacial evaporators derived from renewable lignocellulosic biomass.First,the structural characteristics of lignocellulosic biomass are briefly introduced,serving as photothermal layer or supporting substrates in SDIEs.Secondly,the fabrication methods and processing technologies of lignocellulosic biomass-based evaporators are summarized from the perspective of photothermal layer and supporting substrates.Next,the most recent advances of regulation and optimization strategies are proposed to improve evaporation efficiency.Subsequently,this review summarizes the diverse functionalities of SDIEs,including desalination,power generation,wastewater treatment and antimicrobial,atmospheric water harvesting,and photocatalytic hydrogen production.Finally,the challenges in this field and outlook on the future development are discussed,which are anticipated to provide new opportunities for the advancement of lignocellulosic biomass-based SDIEs.展开更多
Global freshwater scarcity and energy shortages demand integrated solutions.To overcome limitations of traditional solar evaporators,such as salt accumulation,thermal dissipation,and material scalability issues,this s...Global freshwater scarcity and energy shortages demand integrated solutions.To overcome limitations of traditional solar evaporators,such as salt accumulation,thermal dissipation,and material scalability issues,this study presents a biomass-derived three-dimensional(3D)aerogel-based dual-function solar evaporator that simultaneously achieves ultra-high freshwater production and continuous electricity generation.By ingeniously integrating a superhydrophobic inner layer for thermal insulation and buoyancy with a hydrophilic photothermal outer layer for rapid water transport and solar absorption,our design overcomes the trade-offs between evaporation efficiency,salt resistance,and energy loss.The evaporator exhibits exceptional dual performance:an evaporation rate of 3.87 kg m^(-2)h-1(1 sun)and a sustained open-circuit voltage of 222.6 mV,surpassing most reported systems.This synergy originates from ion gradient-driven streaming potentials enabled by selective Na^(+) transport through–COOH/C–OH functionalized microchannels,as verified by molecular dynamics simulations.Crucially,the fabrication process utilizes low-cost biomass materials and scalable techniques,demonstrating significant potential for commercialization.This work not only provides a mechanistic understanding of ion-selective transport in dual-function evaporators but also establishes a paradigm for sustainable co-production of clean water and renewable energy,addressing two pressing global challenges through a single and scalable platform.展开更多
Frost accumulation on the evaporator fins of air source heat pumps(ASHPs)severely degrades heat transfer performance and overall system efficiency.To address this,the present study employs computational fluid dynamics...Frost accumulation on the evaporator fins of air source heat pumps(ASHPs)severely degrades heat transfer performance and overall system efficiency.To address this,the present study employs computational fluid dynamics(CFD)to investigate how fin spacing influences frosting behavior,emphasizing the coupled evolution of frost thickness,density,airflow,and temperature distribution within fin channels.Results reveal that fin spacing is a key parameter governing both the extent and rate of frost growth.Wider fin spacing enhances frost accumulation,with a final frost mass of 6.41 g at 12 mm,about 71.8%higher than at 4 mm.In contrast,narrower spacing suppresses frost formation by accelerating airflow.The frost layer exhibits a distinct two-stage growth pattern:at 12 mm spacing,the early-stage average thickness growth rate reaches 0.021 mm/min,nearly 4.3 times that at 4 mm.Frost density follows similar initial trends across different spacings but diverges later due to thermal resistance and airflow variations.展开更多
Enhancing wastewater treatment efficiency through innovative technologies is paramount in addressing global environmental challenges.This study explores utilizing stereoscopic hydrogel evaporators combined with renewa...Enhancing wastewater treatment efficiency through innovative technologies is paramount in addressing global environmental challenges.This study explores utilizing stereoscopic hydrogel evaporators combined with renewable energy sources to optimize wastewater treatment processes.A cross-linked super absorbent polymer(SAP)hydrogel was synthesized using acrylic acid and 2-hydroxyethyl methacrylate monomers and integrated with a light-absorbing carbon membrane to form a solar-assisted evaporator(MSAP).The MSAP achieved a high evaporation rate of 3.08 kg m^(-2)·h^(-1)and a photothermal conversion efficiency of 94.27%.It demonstrated excellent removal efficiency for dye-polluted wastewater,significantly reducing concentrations of pollutants.The MSAP maintained high performance in outdoor conditions,showcasing its potential for real-world applications.This approach,incorporating both solar and wind energy,significantly boosts water evaporation rates and presents a promising,eco-friendly solution for sustainable wastewater treatment within the circular development framework.展开更多
This paper presents fabrication and testing of a multiple-evaporator and multiple-condenser loop heat pipe (MLHP) with polytetrafluoroethylene (PTFE) porous media as wicks. The MLHP has two evaporators and two condens...This paper presents fabrication and testing of a multiple-evaporator and multiple-condenser loop heat pipe (MLHP) with polytetrafluoroethylene (PTFE) porous media as wicks. The MLHP has two evaporators and two condensers in a loop heat pipe in order to adapt to various changes of thermal condition in spacecraft. The PTFE porous media was used as the primary wicks to reduce heat leak from evaporators to compensation chambers. The tests were conducted under an atmospheric condition. In the tests that heat loads are applied to both evaporators, the MLHP was stably operated as with a LHP with a single evaporator and a single condenser. The relation between the sink temperature and the thermal resistance was experimentally evaluated. In the test with the heat load to one evaporator, the heat transfer from the heated evaporator to the unheated evaporator was confirmed. In the heat load switching test, in which the heat load is switched from one evaporator to another evaporator repeatedly, the MLHP could be stably operated. The loop operation with the large temperature difference between the heat sinks was also tested. From this result, the stable operation of the MLHP in the various conditions was demonstrated. It was also found that a flow regulator which prevents the uncondensed vapor from the condensers is required at the inlet of the common liquid line when one condenser has higher temperature and cannot condense the vapor in it.展开更多
Multiple loop heat pipes which have two evaporators and two condensers in one loop are a kind of active heat transfer device. Since they have two evaporators and two condensers, the operating mode also becomes multipl...Multiple loop heat pipes which have two evaporators and two condensers in one loop are a kind of active heat transfer device. Since they have two evaporators and two condensers, the operating mode also becomes multiple. This work discusses the cases that multiple loop heat pipes were operated with one condenser at high temperature and the other at low temperature. To avoid the high temperature returning liquid and keep the multiple loop heat pipes work properly, the flow regulator which was made of polyethylene was designed, fabricated and applied in this test. The effect of flow regulator was confirmed and analyzed. In the test that large temperature difference existed between two sinks, it can be found according to the result that the flow regulator worked effectively and prevented the high temperature vapor to enter the inlet of common liquid line, which can keep the evaporators and returning liquid to operate at low temperature. With the increment of heat loads and the temperature difference between two sinks, the pressure difference between two condensers became larger and larger. When the pressure difference was larger than the flow regulator’s capillary force, the flow regulator could not work properly because the high temperature vapor began to flow through the flow regulator. According to the test data, the flow regulator can work properly within the sinks’ temperature 0°C/60°C and the two evaporators’ heat load 30/30 W.展开更多
Thermal performance of a loop heat pipe with two evaporators and two condensers was examined using a lumped network model analysis. Thermosyphon-type vertical loop heat pipe and capillary-pump-type horizontal loop hea...Thermal performance of a loop heat pipe with two evaporators and two condensers was examined using a lumped network model analysis. Thermosyphon-type vertical loop heat pipe and capillary-pump-type horizontal loop heat pipe were calculated by examining the change of heating rate of two evaporators. Calculation results showed that the vapor and liquid flow rates in the loop heat pipe and the thermal conductance of the heat pipe changed significantly depending on the distribution ratio of the heating rate of the multiple evaporators. The thermal performance of the vertical loop heat pipe with two evaporators was also examined and experimental results of flow direction and thermal conductance of the heat pipe agreed with the analytical results. The lumped network model analysis is therefore considered accurate and preferable for the practical design of a loop heat pipe with multiple evaporators.展开更多
The refrigerant flow distribution in the parallel flow microchannel evaporators is experimentally investigated to study the effect of header configuration.Six different configurations are tested in the same evaporator...The refrigerant flow distribution in the parallel flow microchannel evaporators is experimentally investigated to study the effect of header configuration.Six different configurations are tested in the same evaporator by installing insertion device and partition plate in the header to ensure the consistency of the other structure parameters.The results show that the uniformity of refrigerant flow distribution and the heat transfer rate are greatly improved by reducing the sectional area of header.The heat transfer rate can increase by 67.93%by reducing the sectional area of both inlet and outlet headers.The uniformity of refrigerant flow distribution and the heat transfer rate become worse after installing the partition plate in the insertion devices and changing the inner structure of the header further.展开更多
The flow field and flow state of thin-film evaporators are complex,and it is significant to effectively divide and quantify the flow field and flow state,as well as to study the internal flow field distribution and ma...The flow field and flow state of thin-film evaporators are complex,and it is significant to effectively divide and quantify the flow field and flow state,as well as to study the internal flow field distribution and material mixing characteristics to improve the efficiency of thin-film evaporators.By using computational fluid dynamics(CFD)numerical simulation,the distribution pattern of the high-viscosity fluid flow field in the thin-film evaporators was obtained.It was found that the staggered interrupted blades could greatly promote material mixing and transportation,and impact the film formation of high-viscosity materials on the evaporator wall.Furthermore,a flow field state recognition method based on radial volume fraction statistics was proposed,and could quantitatively describe the internal flow field of thin-film evaporators.The method divides the high-viscosity materials in the thin-film evaporators into three flow states,the liquid film state,the exchange state and the liquid mass state.The three states of materials could be quantitatively described.The results show that the materials in the exchange state can connect the liquid film and the liquid mass,complete the material mixing and exchange,renew the liquid film,and maintain continuous and efficient liquid film evaporation.展开更多
Objective To prevent the maldistribution of two phase refrigerant in dry expansion evaporators composed of parallel coils, a distributor is needed to supply refrigerant into the coils. Methods A simplified model of...Objective To prevent the maldistribution of two phase refrigerant in dry expansion evaporators composed of parallel coils, a distributor is needed to supply refrigerant into the coils. Methods A simplified model of dry expansion evaporator was proposed. The flow and heat transfer in distributing pipes and evaporator coils were simulated with a numerical method. Results The heat flow rate decreases while the refrigerant is distributed unequally to evaporator coils. Conclusion In order to maintain the heat flow rate, larger heat transfer area should be arranged to make up the effect of maldistribution. The larger the discrepancy of mass flow rate is, the more heat transfer area is needed.展开更多
The development of tellurium(Te)-based semiconductor nanomaterials for efficient light-to-heat conversion may offer an effective means of harvesting sunlight to address global energy concerns.However,the nanosized Te(...The development of tellurium(Te)-based semiconductor nanomaterials for efficient light-to-heat conversion may offer an effective means of harvesting sunlight to address global energy concerns.However,the nanosized Te(nano-Te)materials reported to date suffer from a series of drawbacks,including limited light absorption and a lack of surface structures.Herein,we report the preparation of nano-Te by electrochemical exfoliation using an electrolyzable room-temperature ionic liquid.Anions,cations,and their corresponding electrolytic products acting as chemical scissors can precisely intercalate and functionalize bulk Te.The resulting nano-Te has high morphological entropy,rich surface functional groups,and broad light absorption.We also constructed foam hydrogels based on poly(vinyl alcohol)/nano-Te,which achieved an evaporation rate and energy efficiency of 4.11 kg m^(−2)h^(−1)and 128%,respectively,under 1 sun irradiation.Furthermore,the evaporation rate was maintained in the range 2.5-3.0 kg m^(−2)h^(−1)outdoors under 0.5-1.0 sun,providing highly efficient evaporation under low light conditions.展开更多
Hydrogel-based evaporators have shown great potential in interfacial solar steam generation due to their unique water activation effect.However,the slow water transport still remains a significant challenge limiting t...Hydrogel-based evaporators have shown great potential in interfacial solar steam generation due to their unique water activation effect.However,the slow water transport still remains a significant challenge limiting the continuous and rapid evaporation.Herein,we introduced polyphenol-mediated pore engineering as a new design strategy to construct hierarchically porous hydrogel evaporators,which exhibited an exceptional water transport rate over two orders of magnitude higher than that of ordinary hydrogels.By incorporating gallic acid(GA),a natural polyphenol,into a polyvinyl alcohol(PVA)matrix and applying a directional freezing process followed by ferric ion(Fe3+)coordination,we achieved a dual-scale porous architecture composed of vertically aligned micron channels and GA-induced micropores.This hierarchical structure skillfully balanced the conflicting demands of water transport and water activation.Simultaneously,GA further regulated the water state by increasing the content of intermediate water,thereby significantly reducing the evaporation enthalpy,which finally achieved an admirable evaporation rate of 3.82 kg m^(−2)h^(−1)under one sun irradiation.More importantly,the long-term stability and exceptionally low production cost of this natural molecule-based evaporator enabled an important step towards the possibility of large-scale practical applications.It is believed that this polyphenol-mediated hierarchical porous structured hydrogel provides a new paradigm to accelerate water transport and reduce evaporation enthalpy for efficient and stable solar evaporation.展开更多
Solar-driven interfacial evaporation has shown great potential for achieving desalination with high energy conversion efficiency.However,maintaining a high evaporation rate is challenging due to salt accumulation on s...Solar-driven interfacial evaporation has shown great potential for achieving desalination with high energy conversion efficiency.However,maintaining a high evaporation rate is challenging due to salt accumulation on solar evaporators(SEs),leading to a long-standing trade-off between stable evaporation and salt accumulation in conventional SEs.Inspired by the salt secretion and brine transport mechanisms in mangroves,we present a bio-inspired solar evaporator(BSE)featuring an external photothermal layer and an internal water supply channel.This design enables efficient and continuous evaporation from near-saturated brine using less photothermal material.The BSE exhibits high evaporation performance(3.98 kg m^(–2)h^(–1)for 25 wt% brine),effcient salt collection(1.27 kg m^(–2)h^(–1)for 25 wt% brine),long-term durability(7 d in 25 wt% brine),and zero liquid discharge desalination.Notably,the BSE achieves a record-high water production rate of 3.50 kg m^(–2)h^(–1)in outdoor tests.Furthermore,it can purify World Health Organization-standard freshwater from various types of contaminated water.Importantly,the universality of BSE design is validated by extending it to other solar desalination systems.This work demonstrates a universal SE design,providing key insights into the design of next-generation SEs for efficient and stable evaporation in continuous high-salinity brine desalination.展开更多
Solar-driven interfacial water evaporation technology offers a zero-carbon,sustainable solution for extracting clean water from seawater and wastewater,presenting an effective strategy to address the global water cris...Solar-driven interfacial water evaporation technology offers a zero-carbon,sustainable solution for extracting clean water from seawater and wastewater,presenting an effective strategy to address the global water crisis.This study has employed finite element simulation to investigate the solar interfacial evaporation process,elucidating the interactions between heat,water,and salt during evaporation.Additionally,the internal water channels of the evaporator are optimized and designed using topology optimization techniques.In this project,a cylindrical evaporator model with vertical micropores is developed from carbon-based polymer materials.The impact of pore diameter and spacing on the evaporation rate is analyzed,alongside the effects of thermal conductivity,solar radiation intensity,and ambient wind speed on the evaporator's performance.Simulations have revealed that with a pore diameter of 20μm and a spacing of 0.55 mm,the evaporator achieves the highest evaporation rate of 0.91 kg·m^(-2)·h^(-1).The findings indicate that smaller pore sizes substantially enhance the evaporation rate,while larger pore spacings initially increase,and then decrease the rate.Further optimization involves using 20μm-diameter round pores and adjusting the cross-sectional shapes of the pores based on topological configurations with a material volume factor of 0.5.The optimized structure demonstrates an evaporation rate of 2.91 kg·m^(-2)·h^(-1),representing a 219.78%increase over the unoptimized design.These optimized structures and simulation results provide valuable insights for future evaporator designs.展开更多
Interfacial solar evaporation(ISE)has emerged as a promising technology to alleviate global water scarcity via energy-efficient purification of both wastewater and seawater.While ISE was originally identified and deve...Interfacial solar evaporation(ISE)has emerged as a promising technology to alleviate global water scarcity via energy-efficient purification of both wastewater and seawater.While ISE was originally identified and developed during studies of simple double-layered two-dimensional(2D)evaporators,observed limitations in evaporation rate and functionality soon led to the development of three-dimensional(3D)evaporators,which is now recognized as one of the most pivotal milestones in the research field.3D evaporators significantly enhance the evaporation rates beyond the theoretical limits of 2D evaporators.Furthermore,3D evaporators could have multifaceted functionalities originating from various functional evaporation surfaces and 3D structures.This review summarizes recent advances in 3D evaporators,focusing on rational design,fabrication and energy nexus of 3D evaporators,and the derivative functions for improving solar evaporation performance and exploring novel applications.Future research prospects are also proposed based on the in-depth understanding of the fundamental aspects of 3D evaporators and the requirements for practical applications.展开更多
The development of solar-driven interfacial evaporation technology is pivotal for addressing global water scarcity.However,it is hindered by the difficulty in synergizing high photothermal conversion with low water ev...The development of solar-driven interfacial evaporation technology is pivotal for addressing global water scarcity.However,it is hindered by the difficulty in synergizing high photothermal conversion with low water evaporation enthalpy into a single material.Herein,we propose an iron-aldehyde-cooperative dynamic covalent anchoring strategy,successfully constructing a covalently locked,hydroxymethyl-functionalized PEDOT-PVA integrated dual-network hydrogel(MEPH).This strategy employs Fe3+to achieve the one-step in situ oxidative polymerization of hydroxymethyl EDOT while concurrently forming a physical hybrid network with PVA,which is subsequently reinforced by covalent cross-linking using glutaraldehyde.This design endows the MEPH with exceptional broadband light absorption(>99%),efficient water transport,and regulated water state within the hydrogel matrix,leading to a reduced evaporation enthalpy of 732 J·g^(−1).The resulting evaporator achieves an ultrahigh evaporation rate of 4.95 kg·m^(−2)·h^(−1)under 1-sun illumination,corresponding to an energy conversion efficiency exceeding 95%,while maintaining stable,salt-resistant operation in high-salinity environments.Outdoor experiments validate its outstanding practicality for seawater and wastewater purification,with the produced freshwater significantly promoting plant growth,highlighting its great potential in sustainable agricultural water cycles.This iron-aldehyde-cooperative dynamic covalent anchoring strategy provides an innovative design paradigm for a new generation of high-performance and robust solar evaporators.展开更多
The volatilization characteristics and kinetic mechanisms of arsenic were investigated in the temperature range of 623−773 K and pressure ranges of 10−10000 Pa.The experimental results reveal that the evaporation rate...The volatilization characteristics and kinetic mechanisms of arsenic were investigated in the temperature range of 623−773 K and pressure ranges of 10−10000 Pa.The experimental results reveal that the evaporation rate increases with increasing temperature and decreasing pressure.Surface reaction control dominates at low pressures(<100 Pa),whereas diffusion control dominates at high pressures(>5000 Pa).The evaporation behavior is successfully described by an Arrhenius-type model for temperature dependence and Logistic model for pressure dependence.Key kinetic parameters,including the critical pressure,maximum evaporation rate and evaporation coefficient,were calculated.The evaporation coefficient varies between 0.010 and 0.223,and the critical pressures vary between 281 and 478 Pa with temperature.展开更多
A novel trace nickel(Ni)doped tungsten(W)matrix with coated Ni on W grains was prepared by powder metallurgy method.The introduction of Ni can inhibit the reaction between W and barium-calcium aluminates(Ba-Ca alumina...A novel trace nickel(Ni)doped tungsten(W)matrix with coated Ni on W grains was prepared by powder metallurgy method.The introduction of Ni can inhibit the reaction between W and barium-calcium aluminates(Ba-Ca aluminates)during the impregnation process of the matrix.After cathode activation,the surface Ba:O molar ratio is 0.88:1.00,much higher than the Ba dispenser cathode without Ni doping.The XPS results of the cathode surface showed that the metallic Ba appeared on the activated cathode surface,forming dipoles with oxygen,and effectively reducing the cathode surface work function.The pulse electron emission current density at 1100℃_(b)(brightness temperature)was 18.26 A/cm^(2),and the calculated work function was 1.97 eV.It has a low evaporation rate and the accelerated lifetime test predict a lifetime of over 160000 h.First-principles calculations showed that the charge transfer and dipole moment in the NiW-BaO system were both increased compared to the Ba dispenser cathode,thus improving the emission performance of the Ni-W mixed matrix cathode.展开更多
Gravel mulching plays a vital role in modifying the hydrological cycle in arid and semi-arid areas.Yet,the mechanisms underlying long-term mulching effects on soil evaporation remain poorly understood.To investigate t...Gravel mulching plays a vital role in modifying the hydrological cycle in arid and semi-arid areas.Yet,the mechanisms underlying long-term mulching effects on soil evaporation remain poorly understood.To investigate the hydrological effects of mixed gravel–soil mulching(MGSM),we conducted a controlled 39-d soil evaporation experiment(from 22 July to 30 August 2021)using micro-lysimeters at the field experimental site of Ningxia University,China.The soil evaporation rate(E),cumulative soil evaporation(Ec),soil water content(SWC),mulch resistance(rm),and micro-meteorological variables were assessed for six mulch treatments,each containing a different proportion of gravel by volume:100.00%(M1),80.00%(M2),60.00%(M3),40.00%(M4),20.00%(M5),and 0.00%(M6).The treatments(M2–M6)showed a prolonged soil moisture depletion phase and greater Ec(28.71%–83.31%)relative to the gravel-only treatment(M1)(P<0.050);these effects were primarily attributed to reduced rm.As compared to Ec,the SWC showed an inverse response,decreasing as Cg decreased.A robust exponential relationship was observed between E and rm(P<0.001).Evaporation suppression mediated by rm was particularly pronounced during the residual evaporation stage(>312 h post-wetting),with the strongest effect occurring in M3,where the mean rm doubled.The SWC,mulch properties,and micro-meteorological parameters(i.e.,air relative humidity and surface net radiation flux)were the most important predictors of rm in the mulch treatments.Together,these results suggested that MGSM unexpectedly exacerbated surface soil moisture loss by reducing rm.To mitigate this effect,an optimized mixed gravel–soil mulch,containing 60.00%gravel by volume,might be used;this mixture balances evaporation control with hydrological sustainability and represents a practical strategy for dryland management,offering a compromise between short-term water retention and sustained soil moisture regulation.展开更多
This article presents an adaptive intelligent control strategy applied to a lumped-parameter evaporator model,i.e.,a simplified dynamic representation treating the evaporator as a single thermal node with uniform temp...This article presents an adaptive intelligent control strategy applied to a lumped-parameter evaporator model,i.e.,a simplified dynamic representation treating the evaporator as a single thermal node with uniform temperature distribution,suitable for control design due to its balance between physical fidelity and computational simplicity.The controller uses a wavelet-based neural proportional,integral,derivative(PID)controller with IIR filtering(infinite impulse response).The dynamic model captures the essential heat and mass transfer phenomena through a nonlinear energy balance,where the cooling capacity“Qevap”is expressed as a non-linear function of the compressor frequency and the temperature difference,specifically,Q_(evap)=k_(1)u(T_(in)−T_(e))with u as compressor frequency,Te evaporator temperature,and Tin inlet fluid temperature.The operating conditions of the system,in general terms,focus on the following variables,the overall thermal capacity is 1000 J/K,typical for small-capacity heat exchangers,The mass flow is 0.05 kg/s,typical for secondary liquid cooling circuits,the overall loss coefficient of 50 W/K that corresponds to small evaporators with partial insulation,the temperatures(inlet)of 10℃and the temperature of environment of 25℃,thermal load of 200 W that corresponds to a small-scaled air conditioning applications.To handle system nonlinearities and improve control performance,aMorlet wavelet-based neural network(Wavenet)is used to dynamically adjust the PID gains online.An IIR filter is incorporated to smooth the adaptive gains,improving stability and reducing oscillations.In contrast to prior wavelet-or neural-adaptive PID controllers in HVAC applications,which typically adjust gains without explicit filtering or not tailored to evaporator dynamics,this work introduces the first PID–Wavenet scheme augmented with an IIR-based stabilization layer,specifically designed to address the combined challenges of nonlinear evaporator behavior,gain oscillation,and real-time implementability.The proposed controller(PID-Wavenet+IIR)is implemented and validated inMATLAB/Simulink,demonstrating superior performance compared to a conventional PID tuned using Simulink’s auto-tuning function.Key results include a reduction in settling time from 13.3 to 8.2 s,a reduction in overshoot from 3.5%to 0.8%,a reduction in steady-state error from 0.12℃ to 0.02℃and a 13%reduction in energy overall consumption.The controller also exhibits greater robustness and adaptability under varying thermal loads.This explicit integration of wavelet-driven adaptation with IIR-filtered gain shaping constitutes the main methodological contribution and novelty of the work.These findings validate the effectiveness of the wavelet-based adaptive approach for advanced thermal management in refrigeration and HVAC systems,with potential applications in controlling variable-speed compressors,liquid chillers,and compact cooling units.展开更多
基金supported by grants from National Natural Science Foundation of China(224708046,22508229,22278049)Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)+1 种基金Xingliao Talent Program-Young Top Talent(XLYC2403126)Liaoning Provincial Basic Scientific Research Project for Higher Education(LJ212510152013)。
文摘The increasing scarcity of freshwater resources has driven the rapid emergence of solar-driven interfacial evaporators(SDIEs)as a sustainable approach to harvest fresh water by utilizing solar energy.Lignocellulosic biomass,featuring natural abundance,excellent renewability,unique natural structures,and superior biodegradability compared to the synthetic polymers,is highly attractive for constructing solar steam generators.This review aims to offer an innovative and in-depth insight into designing and optimizing highperformance integrated solar interfacial evaporators derived from renewable lignocellulosic biomass.First,the structural characteristics of lignocellulosic biomass are briefly introduced,serving as photothermal layer or supporting substrates in SDIEs.Secondly,the fabrication methods and processing technologies of lignocellulosic biomass-based evaporators are summarized from the perspective of photothermal layer and supporting substrates.Next,the most recent advances of regulation and optimization strategies are proposed to improve evaporation efficiency.Subsequently,this review summarizes the diverse functionalities of SDIEs,including desalination,power generation,wastewater treatment and antimicrobial,atmospheric water harvesting,and photocatalytic hydrogen production.Finally,the challenges in this field and outlook on the future development are discussed,which are anticipated to provide new opportunities for the advancement of lignocellulosic biomass-based SDIEs.
文摘Global freshwater scarcity and energy shortages demand integrated solutions.To overcome limitations of traditional solar evaporators,such as salt accumulation,thermal dissipation,and material scalability issues,this study presents a biomass-derived three-dimensional(3D)aerogel-based dual-function solar evaporator that simultaneously achieves ultra-high freshwater production and continuous electricity generation.By ingeniously integrating a superhydrophobic inner layer for thermal insulation and buoyancy with a hydrophilic photothermal outer layer for rapid water transport and solar absorption,our design overcomes the trade-offs between evaporation efficiency,salt resistance,and energy loss.The evaporator exhibits exceptional dual performance:an evaporation rate of 3.87 kg m^(-2)h-1(1 sun)and a sustained open-circuit voltage of 222.6 mV,surpassing most reported systems.This synergy originates from ion gradient-driven streaming potentials enabled by selective Na^(+) transport through–COOH/C–OH functionalized microchannels,as verified by molecular dynamics simulations.Crucially,the fabrication process utilizes low-cost biomass materials and scalable techniques,demonstrating significant potential for commercialization.This work not only provides a mechanistic understanding of ion-selective transport in dual-function evaporators but also establishes a paradigm for sustainable co-production of clean water and renewable energy,addressing two pressing global challenges through a single and scalable platform.
基金supported by the Shandong Provincial Natural Science Foundation(ZR2023QE325).
文摘Frost accumulation on the evaporator fins of air source heat pumps(ASHPs)severely degrades heat transfer performance and overall system efficiency.To address this,the present study employs computational fluid dynamics(CFD)to investigate how fin spacing influences frosting behavior,emphasizing the coupled evolution of frost thickness,density,airflow,and temperature distribution within fin channels.Results reveal that fin spacing is a key parameter governing both the extent and rate of frost growth.Wider fin spacing enhances frost accumulation,with a final frost mass of 6.41 g at 12 mm,about 71.8%higher than at 4 mm.In contrast,narrower spacing suppresses frost formation by accelerating airflow.The frost layer exhibits a distinct two-stage growth pattern:at 12 mm spacing,the early-stage average thickness growth rate reaches 0.021 mm/min,nearly 4.3 times that at 4 mm.Frost density follows similar initial trends across different spacings but diverges later due to thermal resistance and airflow variations.
基金financially supported by the“Qing-Lan”Project of Jiangsu ProvinceTop-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)the start-up fund from Yangzhou University。
文摘Enhancing wastewater treatment efficiency through innovative technologies is paramount in addressing global environmental challenges.This study explores utilizing stereoscopic hydrogel evaporators combined with renewable energy sources to optimize wastewater treatment processes.A cross-linked super absorbent polymer(SAP)hydrogel was synthesized using acrylic acid and 2-hydroxyethyl methacrylate monomers and integrated with a light-absorbing carbon membrane to form a solar-assisted evaporator(MSAP).The MSAP achieved a high evaporation rate of 3.08 kg m^(-2)·h^(-1)and a photothermal conversion efficiency of 94.27%.It demonstrated excellent removal efficiency for dye-polluted wastewater,significantly reducing concentrations of pollutants.The MSAP maintained high performance in outdoor conditions,showcasing its potential for real-world applications.This approach,incorporating both solar and wind energy,significantly boosts water evaporation rates and presents a promising,eco-friendly solution for sustainable wastewater treatment within the circular development framework.
文摘This paper presents fabrication and testing of a multiple-evaporator and multiple-condenser loop heat pipe (MLHP) with polytetrafluoroethylene (PTFE) porous media as wicks. The MLHP has two evaporators and two condensers in a loop heat pipe in order to adapt to various changes of thermal condition in spacecraft. The PTFE porous media was used as the primary wicks to reduce heat leak from evaporators to compensation chambers. The tests were conducted under an atmospheric condition. In the tests that heat loads are applied to both evaporators, the MLHP was stably operated as with a LHP with a single evaporator and a single condenser. The relation between the sink temperature and the thermal resistance was experimentally evaluated. In the test with the heat load to one evaporator, the heat transfer from the heated evaporator to the unheated evaporator was confirmed. In the heat load switching test, in which the heat load is switched from one evaporator to another evaporator repeatedly, the MLHP could be stably operated. The loop operation with the large temperature difference between the heat sinks was also tested. From this result, the stable operation of the MLHP in the various conditions was demonstrated. It was also found that a flow regulator which prevents the uncondensed vapor from the condensers is required at the inlet of the common liquid line when one condenser has higher temperature and cannot condense the vapor in it.
文摘Multiple loop heat pipes which have two evaporators and two condensers in one loop are a kind of active heat transfer device. Since they have two evaporators and two condensers, the operating mode also becomes multiple. This work discusses the cases that multiple loop heat pipes were operated with one condenser at high temperature and the other at low temperature. To avoid the high temperature returning liquid and keep the multiple loop heat pipes work properly, the flow regulator which was made of polyethylene was designed, fabricated and applied in this test. The effect of flow regulator was confirmed and analyzed. In the test that large temperature difference existed between two sinks, it can be found according to the result that the flow regulator worked effectively and prevented the high temperature vapor to enter the inlet of common liquid line, which can keep the evaporators and returning liquid to operate at low temperature. With the increment of heat loads and the temperature difference between two sinks, the pressure difference between two condensers became larger and larger. When the pressure difference was larger than the flow regulator’s capillary force, the flow regulator could not work properly because the high temperature vapor began to flow through the flow regulator. According to the test data, the flow regulator can work properly within the sinks’ temperature 0°C/60°C and the two evaporators’ heat load 30/30 W.
文摘Thermal performance of a loop heat pipe with two evaporators and two condensers was examined using a lumped network model analysis. Thermosyphon-type vertical loop heat pipe and capillary-pump-type horizontal loop heat pipe were calculated by examining the change of heating rate of two evaporators. Calculation results showed that the vapor and liquid flow rates in the loop heat pipe and the thermal conductance of the heat pipe changed significantly depending on the distribution ratio of the heating rate of the multiple evaporators. The thermal performance of the vertical loop heat pipe with two evaporators was also examined and experimental results of flow direction and thermal conductance of the heat pipe agreed with the analytical results. The lumped network model analysis is therefore considered accurate and preferable for the practical design of a loop heat pipe with multiple evaporators.
基金the Key Industry Common Key-Technology Innovation Project of Chongqing Municipal Science and Committee(No.cstc2015zdcy-ztzx60001)
文摘The refrigerant flow distribution in the parallel flow microchannel evaporators is experimentally investigated to study the effect of header configuration.Six different configurations are tested in the same evaporator by installing insertion device and partition plate in the header to ensure the consistency of the other structure parameters.The results show that the uniformity of refrigerant flow distribution and the heat transfer rate are greatly improved by reducing the sectional area of header.The heat transfer rate can increase by 67.93%by reducing the sectional area of both inlet and outlet headers.The uniformity of refrigerant flow distribution and the heat transfer rate become worse after installing the partition plate in the insertion devices and changing the inner structure of the header further.
基金National Natural Science Foundation of China(Nos.51905089 and 52075093)Special Fund for Basic Research and Operating Costs of Central Colleges and Universities,China(No.22320D-31)Open Fund for National Key Laboratory of Tribology of Tsinghua University,China(No.SKLTKF20B05)。
文摘The flow field and flow state of thin-film evaporators are complex,and it is significant to effectively divide and quantify the flow field and flow state,as well as to study the internal flow field distribution and material mixing characteristics to improve the efficiency of thin-film evaporators.By using computational fluid dynamics(CFD)numerical simulation,the distribution pattern of the high-viscosity fluid flow field in the thin-film evaporators was obtained.It was found that the staggered interrupted blades could greatly promote material mixing and transportation,and impact the film formation of high-viscosity materials on the evaporator wall.Furthermore,a flow field state recognition method based on radial volume fraction statistics was proposed,and could quantitatively describe the internal flow field of thin-film evaporators.The method divides the high-viscosity materials in the thin-film evaporators into three flow states,the liquid film state,the exchange state and the liquid mass state.The three states of materials could be quantitatively described.The results show that the materials in the exchange state can connect the liquid film and the liquid mass,complete the material mixing and exchange,renew the liquid film,and maintain continuous and efficient liquid film evaporation.
文摘Objective To prevent the maldistribution of two phase refrigerant in dry expansion evaporators composed of parallel coils, a distributor is needed to supply refrigerant into the coils. Methods A simplified model of dry expansion evaporator was proposed. The flow and heat transfer in distributing pipes and evaporator coils were simulated with a numerical method. Results The heat flow rate decreases while the refrigerant is distributed unequally to evaporator coils. Conclusion In order to maintain the heat flow rate, larger heat transfer area should be arranged to make up the effect of maldistribution. The larger the discrepancy of mass flow rate is, the more heat transfer area is needed.
基金the Science and Technology Innovation Council of Shenzhen(Grant Nos.JCYJ20200109105212568,KQTD20170810105439418,JCYJ20200109114237902,20200812203318002,and 20200810103814002)the National Natural Science Foundation of China(Grant No.12274197)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515030240,2019A1515010790,2021A0505110015).
文摘The development of tellurium(Te)-based semiconductor nanomaterials for efficient light-to-heat conversion may offer an effective means of harvesting sunlight to address global energy concerns.However,the nanosized Te(nano-Te)materials reported to date suffer from a series of drawbacks,including limited light absorption and a lack of surface structures.Herein,we report the preparation of nano-Te by electrochemical exfoliation using an electrolyzable room-temperature ionic liquid.Anions,cations,and their corresponding electrolytic products acting as chemical scissors can precisely intercalate and functionalize bulk Te.The resulting nano-Te has high morphological entropy,rich surface functional groups,and broad light absorption.We also constructed foam hydrogels based on poly(vinyl alcohol)/nano-Te,which achieved an evaporation rate and energy efficiency of 4.11 kg m^(−2)h^(−1)and 128%,respectively,under 1 sun irradiation.Furthermore,the evaporation rate was maintained in the range 2.5-3.0 kg m^(−2)h^(−1)outdoors under 0.5-1.0 sun,providing highly efficient evaporation under low light conditions.
基金supported by the National Natural Science Foundation of China(52573087,52225311,and 52422315)the Natural Science Foundation of Sichuan Province(2024NSFSC0240,2024NSFSC1018,and 2025NSFTD0011)+1 种基金the Science and Technology Innovation Program of Hunan Province(2024RC4007)the Institutional Research Fund from Sichuan University(2024SCUQJTX016).
文摘Hydrogel-based evaporators have shown great potential in interfacial solar steam generation due to their unique water activation effect.However,the slow water transport still remains a significant challenge limiting the continuous and rapid evaporation.Herein,we introduced polyphenol-mediated pore engineering as a new design strategy to construct hierarchically porous hydrogel evaporators,which exhibited an exceptional water transport rate over two orders of magnitude higher than that of ordinary hydrogels.By incorporating gallic acid(GA),a natural polyphenol,into a polyvinyl alcohol(PVA)matrix and applying a directional freezing process followed by ferric ion(Fe3+)coordination,we achieved a dual-scale porous architecture composed of vertically aligned micron channels and GA-induced micropores.This hierarchical structure skillfully balanced the conflicting demands of water transport and water activation.Simultaneously,GA further regulated the water state by increasing the content of intermediate water,thereby significantly reducing the evaporation enthalpy,which finally achieved an admirable evaporation rate of 3.82 kg m^(−2)h^(−1)under one sun irradiation.More importantly,the long-term stability and exceptionally low production cost of this natural molecule-based evaporator enabled an important step towards the possibility of large-scale practical applications.It is believed that this polyphenol-mediated hierarchical porous structured hydrogel provides a new paradigm to accelerate water transport and reduce evaporation enthalpy for efficient and stable solar evaporation.
基金supported by Taishan Young Scholar Program(tsqn202306267)the National Natural Science Foundation of China(51802168)the Natural Science Foundation of Shandong Province(ZR2023ME172 and ZR2024ME182)。
文摘Solar-driven interfacial evaporation has shown great potential for achieving desalination with high energy conversion efficiency.However,maintaining a high evaporation rate is challenging due to salt accumulation on solar evaporators(SEs),leading to a long-standing trade-off between stable evaporation and salt accumulation in conventional SEs.Inspired by the salt secretion and brine transport mechanisms in mangroves,we present a bio-inspired solar evaporator(BSE)featuring an external photothermal layer and an internal water supply channel.This design enables efficient and continuous evaporation from near-saturated brine using less photothermal material.The BSE exhibits high evaporation performance(3.98 kg m^(–2)h^(–1)for 25 wt% brine),effcient salt collection(1.27 kg m^(–2)h^(–1)for 25 wt% brine),long-term durability(7 d in 25 wt% brine),and zero liquid discharge desalination.Notably,the BSE achieves a record-high water production rate of 3.50 kg m^(–2)h^(–1)in outdoor tests.Furthermore,it can purify World Health Organization-standard freshwater from various types of contaminated water.Importantly,the universality of BSE design is validated by extending it to other solar desalination systems.This work demonstrates a universal SE design,providing key insights into the design of next-generation SEs for efficient and stable evaporation in continuous high-salinity brine desalination.
基金supported by the National Natural Science Foundation of China(No.52476064,No.52106085)National Key Research and Development Program of China(No.2022YFE0210200)+2 种基金China Postdoctoral Science Foundation(No.2023T160164)Natural Science Foundation of Heilongjiang Province(No.LH2023E043)Fundamental Research Funds for the Central Universities(No.2022ZFJH04,No.HIT.OCEF.2023021)。
文摘Solar-driven interfacial water evaporation technology offers a zero-carbon,sustainable solution for extracting clean water from seawater and wastewater,presenting an effective strategy to address the global water crisis.This study has employed finite element simulation to investigate the solar interfacial evaporation process,elucidating the interactions between heat,water,and salt during evaporation.Additionally,the internal water channels of the evaporator are optimized and designed using topology optimization techniques.In this project,a cylindrical evaporator model with vertical micropores is developed from carbon-based polymer materials.The impact of pore diameter and spacing on the evaporation rate is analyzed,alongside the effects of thermal conductivity,solar radiation intensity,and ambient wind speed on the evaporator's performance.Simulations have revealed that with a pore diameter of 20μm and a spacing of 0.55 mm,the evaporator achieves the highest evaporation rate of 0.91 kg·m^(-2)·h^(-1).The findings indicate that smaller pore sizes substantially enhance the evaporation rate,while larger pore spacings initially increase,and then decrease the rate.Further optimization involves using 20μm-diameter round pores and adjusting the cross-sectional shapes of the pores based on topological configurations with a material volume factor of 0.5.The optimized structure demonstrates an evaporation rate of 2.91 kg·m^(-2)·h^(-1),representing a 219.78%increase over the unoptimized design.These optimized structures and simulation results provide valuable insights for future evaporator designs.
基金financial support from Australian Research Council(FT 190100485,DP 220100583,DP 230102740,and DP 240101581)。
文摘Interfacial solar evaporation(ISE)has emerged as a promising technology to alleviate global water scarcity via energy-efficient purification of both wastewater and seawater.While ISE was originally identified and developed during studies of simple double-layered two-dimensional(2D)evaporators,observed limitations in evaporation rate and functionality soon led to the development of three-dimensional(3D)evaporators,which is now recognized as one of the most pivotal milestones in the research field.3D evaporators significantly enhance the evaporation rates beyond the theoretical limits of 2D evaporators.Furthermore,3D evaporators could have multifaceted functionalities originating from various functional evaporation surfaces and 3D structures.This review summarizes recent advances in 3D evaporators,focusing on rational design,fabrication and energy nexus of 3D evaporators,and the derivative functions for improving solar evaporation performance and exploring novel applications.Future research prospects are also proposed based on the in-depth understanding of the fundamental aspects of 3D evaporators and the requirements for practical applications.
基金financially supported by the Natural Science Foundation of Jiangxi Province(No.20232ACB204002)the Jiangxi Provincial Key Laboratory of Flexible Electronics(No.20242BCC32010).
文摘The development of solar-driven interfacial evaporation technology is pivotal for addressing global water scarcity.However,it is hindered by the difficulty in synergizing high photothermal conversion with low water evaporation enthalpy into a single material.Herein,we propose an iron-aldehyde-cooperative dynamic covalent anchoring strategy,successfully constructing a covalently locked,hydroxymethyl-functionalized PEDOT-PVA integrated dual-network hydrogel(MEPH).This strategy employs Fe3+to achieve the one-step in situ oxidative polymerization of hydroxymethyl EDOT while concurrently forming a physical hybrid network with PVA,which is subsequently reinforced by covalent cross-linking using glutaraldehyde.This design endows the MEPH with exceptional broadband light absorption(>99%),efficient water transport,and regulated water state within the hydrogel matrix,leading to a reduced evaporation enthalpy of 732 J·g^(−1).The resulting evaporator achieves an ultrahigh evaporation rate of 4.95 kg·m^(−2)·h^(−1)under 1-sun illumination,corresponding to an energy conversion efficiency exceeding 95%,while maintaining stable,salt-resistant operation in high-salinity environments.Outdoor experiments validate its outstanding practicality for seawater and wastewater purification,with the produced freshwater significantly promoting plant growth,highlighting its great potential in sustainable agricultural water cycles.This iron-aldehyde-cooperative dynamic covalent anchoring strategy provides an innovative design paradigm for a new generation of high-performance and robust solar evaporators.
基金Yunnan Fundamental Research Project,China(No.202201BE070001-056)。
文摘The volatilization characteristics and kinetic mechanisms of arsenic were investigated in the temperature range of 623−773 K and pressure ranges of 10−10000 Pa.The experimental results reveal that the evaporation rate increases with increasing temperature and decreasing pressure.Surface reaction control dominates at low pressures(<100 Pa),whereas diffusion control dominates at high pressures(>5000 Pa).The evaporation behavior is successfully described by an Arrhenius-type model for temperature dependence and Logistic model for pressure dependence.Key kinetic parameters,including the critical pressure,maximum evaporation rate and evaporation coefficient,were calculated.The evaporation coefficient varies between 0.010 and 0.223,and the critical pressures vary between 281 and 478 Pa with temperature.
基金supported by the National Natural Science Foundation of China(Nos.U2341209 and 52130407).
文摘A novel trace nickel(Ni)doped tungsten(W)matrix with coated Ni on W grains was prepared by powder metallurgy method.The introduction of Ni can inhibit the reaction between W and barium-calcium aluminates(Ba-Ca aluminates)during the impregnation process of the matrix.After cathode activation,the surface Ba:O molar ratio is 0.88:1.00,much higher than the Ba dispenser cathode without Ni doping.The XPS results of the cathode surface showed that the metallic Ba appeared on the activated cathode surface,forming dipoles with oxygen,and effectively reducing the cathode surface work function.The pulse electron emission current density at 1100℃_(b)(brightness temperature)was 18.26 A/cm^(2),and the calculated work function was 1.97 eV.It has a low evaporation rate and the accelerated lifetime test predict a lifetime of over 160000 h.First-principles calculations showed that the charge transfer and dipole moment in the NiW-BaO system were both increased compared to the Ba dispenser cathode,thus improving the emission performance of the Ni-W mixed matrix cathode.
基金supported by the National Key Research and Development Program of China(2021YFD1900600)the National Natural Science Foundation of China(52169010,51869023)+1 种基金the Natural Science Foundation Key Project of Ningxia Hui Autonomous Region(2021AAC02008)the First-Class Discipline Construction Project in Hydraulic Engineering of Ningxia University(NXYLXK2021A03).
文摘Gravel mulching plays a vital role in modifying the hydrological cycle in arid and semi-arid areas.Yet,the mechanisms underlying long-term mulching effects on soil evaporation remain poorly understood.To investigate the hydrological effects of mixed gravel–soil mulching(MGSM),we conducted a controlled 39-d soil evaporation experiment(from 22 July to 30 August 2021)using micro-lysimeters at the field experimental site of Ningxia University,China.The soil evaporation rate(E),cumulative soil evaporation(Ec),soil water content(SWC),mulch resistance(rm),and micro-meteorological variables were assessed for six mulch treatments,each containing a different proportion of gravel by volume:100.00%(M1),80.00%(M2),60.00%(M3),40.00%(M4),20.00%(M5),and 0.00%(M6).The treatments(M2–M6)showed a prolonged soil moisture depletion phase and greater Ec(28.71%–83.31%)relative to the gravel-only treatment(M1)(P<0.050);these effects were primarily attributed to reduced rm.As compared to Ec,the SWC showed an inverse response,decreasing as Cg decreased.A robust exponential relationship was observed between E and rm(P<0.001).Evaporation suppression mediated by rm was particularly pronounced during the residual evaporation stage(>312 h post-wetting),with the strongest effect occurring in M3,where the mean rm doubled.The SWC,mulch properties,and micro-meteorological parameters(i.e.,air relative humidity and surface net radiation flux)were the most important predictors of rm in the mulch treatments.Together,these results suggested that MGSM unexpectedly exacerbated surface soil moisture loss by reducing rm.To mitigate this effect,an optimized mixed gravel–soil mulch,containing 60.00%gravel by volume,might be used;this mixture balances evaporation control with hydrological sustainability and represents a practical strategy for dryland management,offering a compromise between short-term water retention and sustained soil moisture regulation.
文摘This article presents an adaptive intelligent control strategy applied to a lumped-parameter evaporator model,i.e.,a simplified dynamic representation treating the evaporator as a single thermal node with uniform temperature distribution,suitable for control design due to its balance between physical fidelity and computational simplicity.The controller uses a wavelet-based neural proportional,integral,derivative(PID)controller with IIR filtering(infinite impulse response).The dynamic model captures the essential heat and mass transfer phenomena through a nonlinear energy balance,where the cooling capacity“Qevap”is expressed as a non-linear function of the compressor frequency and the temperature difference,specifically,Q_(evap)=k_(1)u(T_(in)−T_(e))with u as compressor frequency,Te evaporator temperature,and Tin inlet fluid temperature.The operating conditions of the system,in general terms,focus on the following variables,the overall thermal capacity is 1000 J/K,typical for small-capacity heat exchangers,The mass flow is 0.05 kg/s,typical for secondary liquid cooling circuits,the overall loss coefficient of 50 W/K that corresponds to small evaporators with partial insulation,the temperatures(inlet)of 10℃and the temperature of environment of 25℃,thermal load of 200 W that corresponds to a small-scaled air conditioning applications.To handle system nonlinearities and improve control performance,aMorlet wavelet-based neural network(Wavenet)is used to dynamically adjust the PID gains online.An IIR filter is incorporated to smooth the adaptive gains,improving stability and reducing oscillations.In contrast to prior wavelet-or neural-adaptive PID controllers in HVAC applications,which typically adjust gains without explicit filtering or not tailored to evaporator dynamics,this work introduces the first PID–Wavenet scheme augmented with an IIR-based stabilization layer,specifically designed to address the combined challenges of nonlinear evaporator behavior,gain oscillation,and real-time implementability.The proposed controller(PID-Wavenet+IIR)is implemented and validated inMATLAB/Simulink,demonstrating superior performance compared to a conventional PID tuned using Simulink’s auto-tuning function.Key results include a reduction in settling time from 13.3 to 8.2 s,a reduction in overshoot from 3.5%to 0.8%,a reduction in steady-state error from 0.12℃ to 0.02℃and a 13%reduction in energy overall consumption.The controller also exhibits greater robustness and adaptability under varying thermal loads.This explicit integration of wavelet-driven adaptation with IIR-filtered gain shaping constitutes the main methodological contribution and novelty of the work.These findings validate the effectiveness of the wavelet-based adaptive approach for advanced thermal management in refrigeration and HVAC systems,with potential applications in controlling variable-speed compressors,liquid chillers,and compact cooling units.
