Heat-stable salts (HSS) accumulate in amine solvents during post combustion CO₂ capture, impairing absorption, increasing corrosion and operating costs. Electrodialysis (ED) is promising for amine purification, but the transport of coexisting HSS ions in three compartment systems and its operating window remain unclear. This study applied a three compartment ED to 30 wt% MEA containing four HSS anions (formate, acetate, oxalate, chloride). Migration was examined in single component and mixed systems, followed by optimization of voltage, flow rate, and concentrate chamber salinity. In single component tests, the order was HCOO⁻ > Cl⁻ ≈ CH₃COO⁻ > C₂O₄²⁻. In mixed system, it shifted to C₂O₄²⁻ > Cl⁻ > HCOO⁻ > CH₃COO⁻, because current distribution follows transport numbers scaling with z², allowing divalent oxalate to overcome its lower diffusivity while bulkier acetate is progressively excluded. At 12 V, 50 L/h, and 2 g/L Na2SO4, HSS removal exceeded 99%, amine recovery remained above 93%, and specific energy consumption was about 0.58 Wh/g HSS. Viscosity decreased and CO₂ absorption capacity partially recovered. A COMSOL model analysed concentration polarization, potential distribution, and flow dependent transport. Tests on industrial lean amine and a cost comparison indicated that three compartment ED offers a competitive balance among HSS removal, amine retention, and treatment cost.

To address the instability of solar energy production and users' electricity demand, the integration of a battery energy storage system (BESS) can mitigate the issue of electricity consumption without altering users' electricity habits. However, the addition of BESS increases the initial investment in the system, and different electricity pricing models also influence the system's operational strategy. Therefore, conventional and mixed operation modes were established under tiered and time-of-use pricing. Trends in net present value (NPV) and self-consumption rate (SC rate) were analyzed for four storage prices (138.50-346.25 USD/kWh) as BESS capacity increased. Results show SC rate is highly influenced by BESS capacity in conventional mode. NPV initially correlates positively with installed PV capacity but turns negative as BESS capacity grows. The mixed mode achieves the highest NPV faster, reducing the BESS capacity needed for economic optimality. Based on these findings, NSGA-II and TOPSIS were used to evaluate system performance and economy. The variation trend of optimal capacity under different weightings offers valuable guidance for selecting storage equipment in similar building applications.

To achieve high selectivity in photocatalytic CO2 reduction (CO2PR), developing ternary layered double hydroxide (LDH) photocatalysts through a simple method is essential. Herein, Er introduction modulates the orbital energies of metal constituents, enhancing unsaturated active sites and forming highly active NiMnEr-LDH. This promotes photogenerated carrier separation and improves reducibility. Under visible light (λ > 400 nm), NiMnEr-LDH achieves a CO production rate of 1403.72 μmol g-1 h-1-about 12.4 times that of pristine NiMn-LDH-with 96.87% CO selectivity. Structural and photoelectrochemical analyses reveal that Er incorporation not only preserves the defect-rich monolayer configuration but also promotes the formation of Ni2+ and Mn3+, creating synergistic metal active sites. The in situ DRIFTS and theoretical calculations demonstrated that Er induces d-d-f orbital overlap among the metals, lowering the energy barrier of the *COOH formation step (0.33 eV) and enabling highly active and selective CO generation. This work provides new insights into efficient photocatalytic CO2 reduction by modulating the orbital structure of LDH layers using rare-earth elements with f-orbitals.

China is actively developing passive houses to improve energy efficiency and reduce primary energy use. These buildings have low actual load characteristics, resulting in a smaller air conditioning terminal heating capacity. However, owing to this limited heating capacity, the air conditioning terminal provides modest indoor air regulation. In practice, occupants of passive houses often open windows for ventilation in winter, resulting in an indoor temperature that is lower than the set value, and it takes a long time for the temperature to return to the desired level. There are few studies that have investigated this issue. Two possible solutions to this issue are proposed: first, altering the external wall structure can enhance the thermal response rate, reducing the time needed for temperature recovery. Secondly, limiting the window-opening area can minimize heat loss during ventilation, thereby maintaining a reasonable indoor temperature. Notably, this may inconvenience occupants. Taking a passive house in Qinghai as a case study, this study discusses the influence of window-opening behavior on the indoor thermal environment. Simulations were conducted to study the window-opening behavior considering different window-opening areas and wall structures. Three different wall structures were considered: internal insulation combined with external insulation (IAE), sandwich insulation combined with external insulation (SAE), and external insulation structures. The results indicate that the IAE and SAE structures cannot effectively improve the indoor thermal environment after opening a window. Overall, changing the wall structure does not reduce the time required to restore room temperature. However, by limiting the opening area of the window, the room temperature can be effectively controlled. Under the given window opening ratio, the room temperature can be stabilized above 18℃. This study offers a practical method for controlling and enhancing the indoor thermal environment, which is applicable to the construction and development of passive houses.

With the intention of capturing carbon dioxide (CO2) on a large scale from indoor air, it is necessary to acquire how different CO2 molecules interact with each other after individual strong adsorption. In this study, CO2 molecules are adsorbed over pure & tungsten (W)-/titanium (Ti)-modified molybdenum disulfide (MoS2) are systematically investigated via density functional theory (DFT) calculations. In calculations, adsorption & transition-state (TS) features of single & double CO2 molecules over MoS2, lowering positions of top-layer sulfur (S) atoms for enhancement of CO2 adsorption strength and thermal performances of adsorption strength & TS energy barriers at high temperature are explored. The results exhibit that most of CO2 adsorption structures over both pure & W-/Ti-modified MoS2 belong to chemisorption except those at top-layer S atoms owing to existence of single lone electron. As to weak physisorption, it is found that lowering z-axis positions of top-layer S atoms could effectively enhance adsorption strength of CO2 because of formation quasi-carbonate structures. For high TS energy barriers, it is proved that doping of W or Ti atoms in MoS2 could largely cut down required TS energy barriers due to catalytic effects of W or Ti atoms. What is more, all chemisorption structures still keep adsorptive at high temperature because of strong bonding and complexity of surficial electron structures. This study can provide sufficient information for utilizing MoS2 as indoor CO2 adsorbents.

Solar visible spectrum (SVS) plays a crucial role in built environments, including building energy, agriculture lighting, circadian rhythm, especially for daylighting performance. The daylighting quality (colorimetric evaluation) could not be dynamic evaluated without considering regional variations of actual SVS. To address this challenge, a year-round global horizontal irradiance measurement experiment was conducted in Beijing, and five Local reference (LR) spectra were established using dimensionality reduction based on a deep autoencoder combined with k-means clustering. The differences in colorimetric evaluation of transmitted daylight when using the LR SVS and the standard illuminant D65 as calculation boundaries were also explored. Findings indicate that the maximum correlated color temperature difference of daylight behind an electrochromic window can reach 7682 K, which highlights the clear advantages of using LR SVS over the standard illuminant in daylight quality research significantly. Moreover, based on LR spectra, a general SVS is established for rapid colorimetric evaluation of transmitted daylight with very small error. Extending this proposed methodology to other regions and applications offers the potential to enhance precision and foster innovation across fields reliant on spectral analysis.

To meet the low-cost heating demand in solar-rich regions, we utilized phase change thermal storage technology to temporarily store excess solar heat during the day and release it at night to improve the energy efficiency. The optimal placement of phase change material was explored, and a phase change radiator (PCR) was proposed. The heating performance of the PCR under typical winter operating conditions was verified through experiments. Using a standalone building in Lhasa as a case, the TRNSYS simulation was employed to assess the economic and environmental benefits of the Solar-PCR heating system under intermittent heating conditions in winter. The results show that the PCR effectively slows down the indoor temperature drop under intermittent heating and maintains the room temperature above 16°C at night. An increase in the supply water temperature can shorten the phase change time and accelerate the rate of room temperature rise, whereas supply water flow rate has a smaller impact on indoor temperature. Furthermore, in January, the PCR application in solar heating systems improves the solar fraction compared to a conventional radiator (CR) from 39.0% to 53.5%, with an annual energy saving rate of 33.2% and a reduction in CO2 emissions by 2098.3 kg.

Particulate matter (PM), as a major source of air pollutants, poses a substantial threat to public health and the environment. Nanofiber air filters, fabricated by electrospinning, are widely recognized for the effectiveness in capturing haze particles. However, achieving the production of large-scale transparent filters in a time-efficient and cost-effective manner remains a challenge. Besides, the inability to recharge the electret nanofibers efficiently hinders the achievement of reusability, long-term reliability, and high-efficiency filtration. Here, a direct spraying method is developed, enabling the rapid construction of large-scale transparent air filters with polyvinylidene fluoride (PVDF) modified by graphene oxide nanosheets (GOn). The filter (PGn) with a meter-scale dimension can be produced in just a few minutes. Coupling with pyroelectric and piezoelectric properties, the filter achieves high removal efficiencies, exceeding 99% for particles ranging from PM0.3 to PM10. Electrostatic charges can be regenerated in real time under moderate temperature variations or gentle mechanical stresses. The PGn filter maintains removal efficiencies of around 90% even after working for 76 h or undergoing four washes. The proposed direct spraying strategy opens up promising pathways to produce large-scale nanofibers, holding significant potential in industrial air purification system manufacturing.

As distributed energy systems become increasingly prevalent, residential energy systems (RES) equipped with photovoltaics (PV) face significant challenges in maintaining supply-demand balance due to power output fluctuations. This necessitates short-term PV power prediction methods that effectively balance accuracy and deployment cost. To address this issue, this paper proposes a novel short-term PV power prediction approach based on low-cost ground-based sky image sequences: the 3DCNN-DLinear model. The method leverages fisheye camera-captured sky images to extract spatiotemporal features via a three-dimensional convolutional neural network (3DCNN), and integrates a lightweight time-series model, DLinear, to enable efficient prediction. The proposed model was evaluated using real-world data collected in Changping District, Beijing, China. A comparative analysis involving six mainstream time-series models confirmed that DLinear achieved the lowest overall prediction error. Further experiments demonstrated that the 3DCNN-DLinear model reduced RMSE by 49.28%, 9.56%, and 8.82% for 30-, 60-, and 90-minute prediction tasks, respectively, compared to the baseline 3DCNN-LSTM model. Additionally, the study examined the contribution of sky image data to prediction accuracy, revealing significant improvements under varying conditions. Notably, RMSE was reduced by 40.4% and 30.5% under sunny and cloudy conditions, respectively, for the 60-minute task. Overall, the proposed method offers an effective and economically viable solution to improve the predictive performance and intelligent scheduling of RES.

Aqueous amines have been identified as effective agents for CO2 capture. However, their significant energy consumption during the regeneration process presents a major challenge, impeding further progress. This study presents a thermomorphic absorbent capable of regenerating at low temperatures. At a temperature of 323 K, the absorbent achieves a regeneration efficiency of 86.73 % in a water bath. Building on this capability, the desorption efficiency was further improved by incorporating photothermal nanotubes into the solution, replacing steam with photothermal energy for CO2 desorption. This modification resulted in desorption efficiency comparable to that of the water bath at the same temperature. Furthermore, the absorption performance of the thermomorphic absorbent was evaluated, revealing a maximum upper-layer absorption capacity of 0.03885 g/g solvent and a lower-layer capacity of 0.08945 g/g solvent. The incorporation of carboxylated multi-walled carbon nanotubes not only acted as photothermal materials during desorption but also increased the solution absorption capacity by 25.93 % and sustained high absorption rates over time. Additionally, the presence of nanotubes boosted the solvent's cycling capacity by 86.44 % compared to its absence. Fourier transform infrared testing and liquid nuclear magnetic resonance carbon spectroscopy of the thermomorphic absorbents indicated the formation of HCO3 -, an unstable compound prone to decomposition, which facilitates low-temperature CO2 desorption. The regeneration energy consumption of the thermomorphic absorbent was evaluated to be 1.10 GJ/ ton CO2, representing a 72.43 % reduction in energy consumption compared to 30 % MEA. This finding underscores the potential of the thermomorphic absorbent as a promising candidate for CO2 capture.

In this paper, we present a comprehensive optimization framework that identifies renovation plans to minimize half-life cycle carbon emissions, investment payback period, and indoor discomfort hours. The framework consists of four stages. First, relevant data were collected, building models were established, and the renovation scope and preliminary parameters were determined. Second, a sensitivity analysis of the initial parameter set was conducted, and important parameters were selected and input into a back-propagation neural network model for prediction. Finally, an optimal renovation plan was obtained through multi-objective optimization and the technique for order of preference by similarity to the ideal solution (TOPSIS) decision-making. To illustrate the framework's feasibility, it was applied to a building as an example. Remarkably, carbon emissions were reduced by 82.2 %, and zero carbon was achieved during the half-life cycle. Moreover, this achievement resulted in a relatively swift payback period of 3.9 years, coupled with a commendable 30 % decrease in indoor discomfort hours. Hence, the framework is effective in optimizing building renovation objectives, yielding a more harmonious and ideal building renovation strategy, and can be widely utilized to enhance building performance.

This study experimentally evaluates an innovative double counter-flow dew-point evaporative cooler with efficient wet-channel materials for residential building cooling. Tested under varying conditions in a double enthalpy-difference laboratory, the system achieves 118% wet-bulb effectiveness and 83% dew-point effectiveness at a 1:1 secondary/primary air ratio (dry-bulb temperature of 38 degrees C and wet-bulb temperature of 23 degrees C), delivering 3.31 kW cooling capacity. Compared to other existing systems, wet-bulb and dew-point effectiveness improve by 11.74% and 10.67%, respectively. The coefficient of performance (i.e. COP) reaches 10-13.2 in dry regions and 8.4 in humid climates, demonstrating superior energy efficiency for sustainable air conditioning. The new dew-point indirect evaporative cooler adopts a new structural design, wet material, and intermittent water supply scheme, which significantly improves the wet-bulb effectiveness, dew-point effectiveness, and COP compared with existing air coolers of the same type, and provides new ideas for material and structural innovations in subsequent research.

Two amine-incorporated composites, TETA@MIP-206-OH and TREN@MIP-206-OH, were facilely fabricated by incorporation of triethylenetetramine (TETA) and tris(2-aminoethyl)amine (TREN), respectively, into a hydroxyl-containing robust metal-organic framework, MIP-206-OH for enhancing CO2 adsorption. Characterizations revealed that the two amines were both successfully loaded into the pores by the interactions between the phenolic hydroxyl sites in the porous skeleton and the introduced amines groups without disrupting the inherent structure of MIP-206-OH. CO2 sorption experiments revealed that TETA@MIP-206-OH(1:1) possesses a CO2 adsorption capacity of 20.76 +/- 2.3 cm(3)/g at 298 K and 1 atm, which is similar with that of MIP-206-OH itself (20.32 cm(3)/g) at the same condition. But, at relative lower pressure (P/P-0 < 0.1), TETA@MIP-206-OH(1:1) exhibits much higher CO2 adsorption capacity that of MIP-206-OH itself, which finally is attributed to chemisorption feature verified by desorption hysteresis and Fourier transform infrared spectra measurements. TREN@MIP-206-OH(10:1) exhibits a higher CO2 adsorption capacity than both of them not only at lower pressure (P/P-0 < 0.1) but also at about 1 atm with a value of 35.07 +/- 0.59 cm(3)/g at 298 K. Moreover, the recycle sorption experiments revealed TETA@MIP-206-OH(1:1) composite can be reused for CO2 adsorption after being reactivated by heating, while the loaded aliphatic amines were still well immobilized in the framework even after running ten cycles of the CO2 sorption experiments. This work successfully demonstrated that incorporating aliphatic amines into hydroxyl-containing porous materials by simple acid-base interactions, effective recyclable adsorbents for CO2 capture can be facilely achieved.

Replacing steam with solar for CO 2 regeneration is an incredibly promising approach. However, the high temperature required for solvent regeneration and the less -than -optimal photothermal conversion efficiency that prevents reaching the necessary regeneration temperature are significant limitations to this approach. In this work, thermomorphic solvents containing dimethylcyclohexylamine, N-methylcyclohexylamine and photothermal nanoparticles were prepared for CO 2 capture. Nano carbon black, multi -walled carbon nanotube and carboxyl group functionalized multi -walled carbon nanotube were used as promoter for photothermal conversion. The experimental results exhibit the high CO 2 absorption capacity of 0.1081 g/g solvent for the carboxyl group functionalized multi -walled carbon nanotube based solvent, and it can be efficiently regenerated under solar irradiation at a low temperature of - 323 K. It is noteworthy that the photothermal material not only raise the solution temperature( -325 K) during solar irradiation but also boosts the CO 2 absorption rate, and leads to a - 20.8 % increase in CO 2 absorption capacity during the absorption process. Furthermore, the utilisation of photothermal regeneration for thermomorphic solvents can achieve an efficiency of 78.6 %, with a regeneration heat of 2.35 GJ/t CO 2 , resulting in an energy consumption reduction of approximately 41.1 % in comparison to 30 wt% monoethanolamine. The photo triggered regeneration of the thermomorphic solvent investigated in this study shows promising potential as an energy -efficient carbon capture technology.

Deep eutectic solvents (DESs) have attracted great interest as a new green alternative to ionic liquids. In order to investigate the potential of using DESs to replace traditional organic solvents in carbon capture processes, it is necessary to understand in detail the physicochemical and thermodynamic properties of DESs before and after CO2 absorption. In this paper, choline chloride was used as the hydrogen bond acceptor and ethanolamine as the hydrogen bond donor to prepare the original DES. Afterward, 5 % mass fraction of morpholine/sarcosine is then added to make two kinds of ternary secondary amine functionalized DESs. Six quaternary DESs were finally prepared by mixing 20 % solvent (water/glycerol/ethylene glycol) with the ternary DESs. Subsequently, the physicochemical properties of DESs, such as melting point, density, viscosity and surface tension, were experimentally determined over the temperature range of 303.15-353.15 K. The properties of ternary and quaternary DESs before and after CO2 absorption were especially predicted and analyzed using different models. It was found that the Vogel-Fulcher-Tamman model was more suitable for forecasting viscosity, and the Pelofsky equation was better for prediction of the relationship between surface tension and viscosity. Based on the experimental data and the solvent critical values predicted by the state equation, the thermodynamic properties of ternary and quaternary DESs before and after CO2 absorption, such as molar volume, isobaric expansion coefficient, lattice energy, activation energy, viscous flow entropy and enthalpy, were derived and analyzed.

With the serious climate change and carbon emissions issues facing the world, it is becoming increasingly important to find effective methods to reduce the post-combustion CO2 concentrations. Piperazine -enhanced aqueous amine solvents are still being developed due to the technology is more applicable to large -scale industry. However, the sustainability of the CO2 capture process is still hindered by high energy consumption and amine losses. To tackle this issue, a novel secondary amine, 2-cyclopentylaminoethanol, was synthesized from a primary amine, monoethanolamine. It has a more stable structure than monoethanolamine and was further activated by piperazine. Its effectiveness was compared with piperazine-enhanced N-methyldiethanolamine, N-methyldiethanolamine/triethylenediamine, and 2-amino-2-methyl-1-propanol. The experimental results showed that 2-cyclopentylaminoethanol/piperazine presents the fastest CO2 mass transfer rate, the largest CO2 cyclic capacity and a lower latent heat. The regeneration energy consumption of the absorbent is approximately 2.44 GJ/ton CO2, which is approximately 37.45% lower than that of 30 wt% monoethanolamine solvent. The results are in accordance with the findings of a laboratory-scale pilot plant study, which demonstrated an average reduction of 35.3% in energy consumption. Molecular simulations have revealed that 2-cyclopentylaminoethanol exhibits the lowest energy barrier for reacting with CO2, rendering it more conducive to CO2 reaction. The intermolecular interactions indicate that the hydrogen bonding in the solution after monoethanolamine reacts with CO2 becomes more pronounced, coupled with a higher energy barrier. Consequently, a greater amount of energy is required during desorption. It can be inferred that 2-cyclopentylaminoethanol/piperazine is a promising energy-efficient and stable absorbent for post-combustion CO2 capture.

Leveraging solar irradiation for regenerating amine materials presents a promising alternative to conventional steam-based CO2 regeneration, potentially mitigating environmental concerns associated with rising CO2 levels. However, this method has limitations and needs substantial improvements in both regeneration efficiency and photo-thermal conversion efficiency, which are closely tied to the performance of the photo-thermal materials. The development of highly efficient photo-thermal conversion materials is crucial for the successful implementation of this technology. In this review, we focus on the utilization of light-irradiated amine materials for CO2 regeneration and conversion. We compare and analyze their performance in terms of regeneration efficiency, temperature achieved, properties of the photo-thermal conversion materials and advantages and disadvantages of various photo-thermal materials. Additionally, we provide suggestions for enhancing these materials based on the research findings and discuss the potential future directions. Moreover, we address the challenges and feasibility of replacing traditional steam-based methods with light-activated CO2 regeneration in industrial applications, aiming to foster more efforts towards the industrial-scale utilization of solar-irradiated CO2 regeneration and conversion.

In addressing concerns related to symptoms like dizziness, nausea, and reduced productivity stemming from elevated indoor CO2 2 levels, the primary objective of the current CO2 2 adsorption technology is to enhance the adsorption capacity. However, the stability and applicability of the adsorbent are of greater importance in indoor carbon capture than in other settings. This study examines the performance and stability of indoor CO2 2 capture using propylene oxide-modified tetraethylenepentamine supported on novel super carbon, gas-phase hydrophilic silica dioxide, and graphitic phase carbon nitride carriers. The corresponding painted films were developed to facilitate the application in indoor CO2 2 capture. Thermogravimetric analysis demonstrates that the propylene oxide-modified materials are more stable than the unmodified compositions. The findings indicate that an optimal adsorption capacity is achieved when water is used as the solvent and carboxymethyl cellulose sodium as a dispersant, while maintaining a carrier-to-tetraethylenepentamine mass ratio of 1:0.75. Furthermore, the painted films are stably formed by using isopropanol instead of water, and the tetraethylenepentamine-topropylene oxide molar ratio of 1:2 for super carbon and graphitic phase carbon nitride as carriers, which exhibit notable enhancements in adsorption performance by 160.0 % and 41.8 %, respectively. The film using super carbon as supporter exhibited the highest adsorption capacity of 122.83 mg/g. This suggests that the compositions are more readily available for indoor CO2 2 capture by coating in everyday scenarios. Notably, even after undergoing five adsorption-desorption cycles, the desorption efficiency of the solid amine adsorbent remains consistently above 95 %.

Building flexible energy systems (BFES) can be enhanced by introducing storage batteries. Providing timely scheduling strategies for flexible resources can improve the system's energy utilization. BFES's scheduling strategies are often adjusted based on Intra-hour photovoltaic(PV) output. Intra-hour PV power generation can be predicted by analyzing cloud imagery data; however, this method does not meet the economic requirements of BFES due to its cost and instrumentation. Therefore, this study proposes a low-cost method for intra-hour PV power generation prediction (IHP) for BFES and explores the impact of integrating this approach into BFES on the rate of renewable energy consumption. This method combined low-quality sky images captured using fisheye cameras installed above buildings with historical electricity generation data and employed convolutional neural networks. The feasibility of the IHP method and the advantages of incorporating it into BFES were verified by applying it to a building equipped with PV devices in Changping, Beijing. The performance of the proposed model algorithm was compared with those of existing models. The proposed method achieved average prediction accuracy improvements of 25.1 and 12.5 % compared with existing models under sunny and cloudy conditions, respectively. Under clear conditions, the model could predict the PV power generation within the next 25 min, whereas under cloudy conditions, the model could predict the power generation within 10 min. In addition, integrating IHP into the scheduling strategy of BFES can improve the renewable energy consumption rate by 44.4 % on the original basis.