Building Energy Conservation Research Articles

CO2 adsorption properties of aerogel and application prospects in low-carbon building materials: A review

The applications and researches of the aerogel in the field of building materials and building energy conservation had been widely concerned due to its excellent thermal insulation properties. However, it has not been paid attention that the potential application values for excellent CO2 adsorption properties of aerogel in building materials. The CO2 adsorption properties of aerogel and the research progress on utilizing SiO2 aerogel in building materials had been reviewed. And the application prospect of the technologies that exploit the CO2 adsorption properties of aerogel and the carbonization technology to prepare SiO2 aerogel-based low-carbon building materials was discussed. It was shown that the type, morphology, and pore structure of aerogel significantly affect the resulting carbon adsorption performance. Amino modification was an effective method for improving the carbon adsorption capacity of aerogel. The performance of aerogel-incorporated cement-based composites could be optimized by improving the performance of binder materials, modifying the aerogel, or preparing new aggregates by loading aerogel into porous materials with higher strength. In addition, it was feasible to prepare new green low-carbon building materials by using aerogel as thermal insulating aggregate and carbon adsorption material, industrial solid wastes rich in alkali metal ions as cementitious materials, and carbonation curing technology. The purpose of this review was to promote the application of CO2 adsorption properties of aerogel in building materials, and enhance the development of low-carbon (or zero-carbon, or negative-carbon) building materials. This is of great significance for reducing carbon emissions in the construction sector and promoting the "carbon neutrality" of global.

Adjustment of phase change temperature using KCl to develop composite phase change materials based on super absorbent polymer as carrier for use in building energy conservation

In the present work, a Na2HPO4·12H2O–KCl/SAP composite phase change material (CPCM) adapted to the comfortable indoor temperature of the human body has been successfully prepared. The CPCM was developed by physical mixing of Na2HPO4·12H2O (DSP) as the main PCM, KCl as temperature regulator and super absorbent polymer as carrier. In addition, the CPCM was characterized by various techniques, and its thermal properties were analyzed. The results showed that the phase change temperature (Tm) of DSP could be adjusted from 35.8 °C to 32.7 °C by KCl and the DSP-KCl mixture containing 4 % KCl had a high enthalpy value (241.5 kJ kg−1). The cooling curve test found that adding 0.75 % nano-α-Al2O3 as nucleating agent could greatly reduce the supercooling degree of DSP-KCl mixture to 3.39 °C. Adding 14 % SAP into the mixture can solve the leakage and reduce the supercooling degree and thermal conductivity. The resulting CPCM with 14 % SAP added had appropriate Tm (26.9 °C), high enthalpy value (153.5 kJ kg−1), low supercooling degree (1.34 °C) as well as thermal conductivity (0.3079 W K−1 m−1) and excellent thermal reliability. These results indicated that the CPCM was suitable for the field of building energy conservation.

Optimal Design and Simulation Analysis of Phase Change Material Composite Self-Insulating Block in a Typical Cold Region City of China in Summer

Background:: Incorporating PCMs (Phase Change Materials) into the building envelope can achieve the purpose of regulating heat transfer and enhancing indoor comfort. In recent years, lots of patents for new phase change concretes have been proposed and applied to the envelope. Objective:: This study aimed to explore the optimum phase change temperature and installation position of PCM by optimizing different concrete blocks to improve the thermal behavior of concrete compound self-insulating blocks. Methods:: Firstly, based on the existing patents, five new types of phase change self-insulating blocks were proposed. The thermal insulation performance of different blocks was tested using ANSYS simulation. Then, the feasibility of using EnergyPlus to simulate the thermal environment of the room was verified by taking a summer south-facing room in Hohhot City as a research object. Finally, 13 phase-change block types containing 4 phase-change temperatures and 3 PCM installation locations were designed for further testing. Results:: A three-row staggered perforated block was selected, and the heat transmission coefficient of the masonry wall was 0.437 W/(m2·K). The optimal phase change temperatures of outdoor, medium- temperature, high-temperature, and low-temperature periods in summer, were 24.0 oC, 30.0 oC, and 28.0 oC, respectively. The optimal phase change temperature in the whole summer was 26.0~ 28.0 oC, and the best phase transition layer location was the inner hole of the block. Conclusion:: The PCM mounting position has a greater effect on room temperature than the PCM phase change temperature. The study results are of great significance for stabilizing room temperature and building energy conservation.

Preparation and Thermal Performances of Lauric Acid/Polyvinyl Butyral/Graphene Nanoplates Composite Phase Change Materials

In recent years, there has been significant progress in the development and application of phase change materials (PCMs) for thermal energy storage. The new lauric acid (LA)/polyvinyl butyral (PVB)/graphene nanoplates (GNP) composite phase change materials (CPCM) are prepared using the solution blending method, in which LA acts as PCM, PVB serves as support material, and GNP is used as thermally conductive enhancer. The prepared CPCM with 80 wt% LA can retain stable shape without leakage. The Fourier‐transform infrared and X‐ray diffractometer results indicate that there is no chemical reaction among the various components of the CPCM. The differential scanning calorimeter results show the CPCM3 (with 80 wt% LA and 5 wt% GNP) has melting latent heat of 134.41 KJ Kg−1 with melting temperature of 41.73 °C. The thermal conductivity tests present that thermal conductivity of CPCM3 is 0.689 W (m K)−1, which is 3.83 times that of the PCM2. The thermogravimetric analyzer results verify that the CPCM possess good thermal stability within the operating temperature range of 35–45 °C without any degradation. The thermal cycling tests indicate that CPCM have good thermal reliability. Therefore, it has promising applications in building energy conservation, solar thermal systems, thermal management, and textiles.

Investigating the influence of reflective materials on indoor thermal environment and solar reflectance in buildings

This in-depth study explores the intricate dynamics of reflective materials, emphasizing their impact on the indoor thermal environment and urban heat island (UHI) mitigation. Examining diffuse highly reflective (DHR), general reflective (GR), and retro-reflective (RR) materials on a simplified building model during summer days, the research utilizes outdoor experiments to analyze air and surface temperatures, as well as solar radiation. Prioritizing key metrics—mean radiant temperature (MRT), operative temperature (OT), and solar reflectance (ρ)—the study uncovers nuanced distinctions in DHR, GR, and RR materials. Solar reflectance calculations consistently show higher values for DHR and RR materials compared to GR material, highlighting reflectance's pivotal role in influencing surface temperatures and indoor thermal environment. When evaluating the impact of exterior wall materials on building temperatures, RR material with a 76% reflectance performs similarly to DHR material (82%). Notably, with a 6% lower reflectance in RR, the temperature contrast between external and internal walls is only about 1.5 °C at its maximum, underscoring RR's effectiveness as an outer wall material for UHI mitigation and building energy conservation, surpassing both DHR and GR materials.

Robust and wear-durable coating based on halloysite nanotubes/polymer composite for passive daytime radiative cooling

Passive daytime radiative cooling (PDRC) is an efficient strategy to achieve cooling through spectrally selective emission and high solar spectrum reflection. Current preparation strategies for PDRC materials mainly involve doping inorganic micro-nanoparticles into polymers, but their solar reflectance is usually insufficient. Here, we designed a super-white inorganic coating on different substrates based on natural halloysite nanotubes (HNTs) through the doctor blade method. Polyvinyl alcohol (PVA) and water-based acrylic resin (AR) were introduced to increase the adhesion for obtaining robust inorganic coating. HNTs/PVA/AR composite coating shows excellent water resistance, wear resistance, and environmental tolerance, which is mainly due to the strong interfacial interactions between HNTs, PVA, and AR. Compared with the uncoated transparent plastic, the coated plastic exhibits a super-white appearance (whiteness of ∼95%) and maximum solar reflectance of ∼97%. The maximum temperature difference of the HNTs/PVA/AR coated and pristine copper sheet is 15 °C under simulated sunlight. The PDRC property is related to the high surface roughness of the coating composed of disordered high-aspect ratio nanotubes and the high whiteness of the raw halloysite materials. The composite coating can tolerate pH from 1–13, temperature change (−60∼250 °C), and different salt environments. The composite coating increases thermal stability, flame retardancy, and giving protective effect of dye against UV degradation. In addition, the HNTs/PVA/AR coated plastic as packaging materials can maintain good freshness of different fruits under strong solar irradiation. The robust HNTs/PVA/AR composite coating with high PDRC properties shows promising application in food packaging, building energy conservation, metal anticorrosive coating, and sunscreen products.

Rural Residents’ Willingness to Adopt Energy-Saving Technology for Buildings and Their Behavioral Response Path

There is an urgent need to promote the technical means of energy conservation in rural buildings. However, it is difficult to inspire enthusiasm among rural residents to implement the mandatory building energy conservation policy, resulting in invisible and avoidable waste. Based on the characteristics of energy-saving technology for buildings and the theory of planned behavior, structural equation modeling was adopted to explore the transformation process of the “cognition–willingness–behavior” of rural residents. The model results validate the hypothesis that behavioral attitudes, subjective norms and perceived behavioral control influence the adoption of energy-efficient building technologies by rural residents. The results show that in terms of the factors influencing rural residents’ willingness to adopt building energy-saving technology, behavioral attitudes have the greatest impact, followed by subjective norms and perceived behavior control, and that rural residents’ subjective norms can indirectly promote their willingness to adopt building energy-saving technology, which is mediated through their behavioral attitudes. The paper concludes with suggestions for countermeasures to enhance buildings’ energy efficiency and energy management in rural areas.

A Review of Metaheuristic Optimization Techniques for Effective Energy Conservation in Buildings

The built environment is a significant contributor to global energy consumption and greenhouse gas emissions. Advancements in the adoption of environmentally friendly building technology have become crucial in promoting sustainable development. These advancements play a crucial role in conserving energy. The aim is to achieve an optimal design by balancing various interrelated factors. The emergence of innovative techniques to address energy conservation have been witnessed in the built environment. This review examines existing research articles that explore different metaheuristic optimization techniques (MOTs) for energy conservation in buildings. The focus is on evaluating the simplicity and stochastic nature of these optimization techniques. The findings of the review present theoretical and mathematical models for each algorithm and assess their effectiveness in problem solving. A systematic analysis of selected algorithms using MOT is conducted, considering factors that influence wellbeing, occupant health, and indoor environmental quality. The study examines the variations among swarm intelligence MOTs based on complexity, advantages, and disadvantages. The algorithms’ performances are based on the concept of uncertainty in consistently providing optimal solutions. The paper highlights the application of each technique in achieving energy conservation in buildings.

Navigating legal pathways for accelerating urban energy transition: A comprehensive deep analysis of photovoltaic power prediction and policy instruments

This research proposes a navigation method that explores how to accelerate urban energy transformation through legal means from the perspective of energy law, in order to improve the accuracy of photovoltaic output power prediction in sustainable energy transformation. Firstly, a deep learning model based on adversarial autoencoder (AAE) architecture was introduced to predict photovoltaic output power according to clean environment policies. Secondly, in order to effectively fine tune the parameters of AAE, a heuristic optimization method based on the Imperial Competition Algorithm was proposed to optimize the AAE configuration to adapt to the unique characteristics of photovoltaic systems, thereby improving prediction accuracy. In addition, the study analyzed the challenges and opportunities faced by current urban energy transformation, and then proposed sustainable ways to accelerate urban energy transformation from the aspects of formulating transformation plans, promoting technological innovation, promoting green transportation, promoting building energy conservation, and developing circular economy. The synergistic effect of deep learning and heuristic optimization, combined with strict stability and sensitivity assessment, puts this research at the forefront of advancing photovoltaic output power prediction methods, which is of great significance for optimizing renewable energy utilization and grid integration.

Theoretical Framework and Research Proposal for Energy Utilization, Conservation, Production, and Intelligent Systems in Tropical Island Zero-Carbon Building

This study aims to theoretically explore the technological systems of tropical island zero-carbon building (TIZCB) to scientifically understand the characteristics of these buildings in terms of energy utilization, energy conservation, energy production, and intelligent system mechanisms. The purpose is to address the inefficiencies and resource wastage caused by the traditional segmented approach to building energy consumption management. Thus, it seeks to achieve a comprehensive understanding and application of the zero-carbon building (ZCB) technology system. This article focuses on the demands for energy-efficient comfort and innovative industrialization in construction. Through an analysis of the characteristics of TIZCB and an explanation of their concepts, it establishes a theoretical framework for examining the system mechanisms of these buildings. Additionally, it delves into the energy utilization, energy conservation, energy production, and intelligent system from macro, meso, and micro perspectives. This approach results in the development of an implementation strategy for studying the mechanisms of energy usage, conservation, and intelligent production systems in TIZCB. The results show that: (1) this study delves into the theoretical underpinnings of TIZCB, emphasizing their evolution from a foundation of low-carbon and near-zero energy consumption. The primary goal is to achieve zero carbon emissions during building operation, with reliance on renewable energy sources. Design considerations prioritize adaptation to high-temperature and high-humidity conditions, integrating regional culture along with the utilization of new materials and technologies. (2) A comprehensive technical framework for TIZCB is proposed, encompassing energy utilization, conservation, production capacity, and intelligent systems. Drawing from systems theory, control theory, and synergy theory, the research employs a macro–meso–micro analytical framework, offering extensive theoretical support for the practical aspects of design and optimization. (3) The research implementation plan establishes parameterized models, unveiling the intricate relationships with building performance. It provides optimized intelligent system design parameters for economically viable zero-carbon operations. This study contributes theoretical and practical support for the sustainable development of TIZCB and aligns with the dual carbon strategy in China and the clean energy free trade zone construction in Hainan.

KCA/Na2SiO3/PNIPAm hydrogel with highly robust and strong solar modulation capability for thermochromic smart window

Thermochromic smart windows have strong competitive advantages in the realm of building energy conservation. However, achieving thermochromic smart window with a lower critical solution temperature (LCST), high solar modulation (ΔTsol), and excellent visible light transmittance (Tlum) remains a great challenge. Here, a novel composite hydrogel based on polydiisopropylacrylamide (PNIPAm) doped with carrageenan (KCA) and Na2SiO3 was developed for high-performance smart window. The lower LCST of PNIPAm was precisely tuned in a range from 25 °C to 28 °C by controlling the content of added Na2SiO3. The inclusion of KCA diminishes agglomeration within the gel system and enhances both Tlum and ΔTsol. As a result, the KCA/Na2SiO3/PNIPAm exhibits a high Tlum (87.37 %), ΔTsol (69.65 %), a lower LCST (27.2 °C), and a high atmospheric window emissivity (0.962). The smart window achieves temperature drop of 12.3 °C under direct sunlight, and keeps highly stable even after 100 cycle tests high and low-temperature durability due to its robust solar modulation capability. This work offers valuable insights for developing high-performance and robust thermochromic smart windows and holds promising applications in building energy conservation.

Energy efficiency retrofitting measures of an institutional building: A case study in eastern India

Increasing energy demand and greenhouse gas emissions are major concerns in India. Building energy use in India accounts for 33 % of total energy consumption and is growing at an annual rate of 8 %. In order to save energy, energy conservation in buildings should be given primary importance. Energy conservation practices can reduce energy use in buildings while maintaining thermal comfort. This can be achieved by optimising existing energy use or lowering consumption. One such initiative was undertaken by Siksha 'O' Anusandhan Deemed to be University. It analysed the energy consumption pattern and possible energy conservation opportunities (ECOs) to lower energy usage in its buildings at campus 1 in Bhubaneswar. The Energy Conservation Building Code Odisha (OECBC) was followed to reduce energy use by replacing all the damaged windows with efficient glazing. By following OECBC guidelines, we can save up to 30 % of the energy consumed by an existing building. Besides, energy conservation measures were performed by replacing ceiling fans with brushless direct current (BLDC) fans, existing lights with LED bulbs, and using variable speed drives instead of induction motors. This study will help to define the most efficient energy conservation measures for existing buildings in terms of cost and energy savings. Retrofitting the present building with energy-saving devices will cost INR 21, 32, 90,152 with an overall annual energy savings of 47, 28,177 kWh and a yearly cost saving of INR 319,66,703.

Paper: Modeling and scenario analysis of residential building energy conservation in cities of different weather

Building models are used to predict energy consumption and CO2 emissions under current and future conditions and serve as a basis for building design. The most important energy saving potentials in buildings can be achieved by improving the thermal performance of building and the efficiency of the district heating system. This study investigated energy savings in buildings in cold and hot regions of China and Africa and developed a modeling approach for energy savings in heating and cooling of residential buildings. We have provided an overview of long-term scenarios for energy demand and carbon dioxide (CO2) emissions. Using the industry-renowned software RETScreen, parameter simulations and optimizations are performed over the three time periods (currently 2030 and 2050). As a result, it was found that energy consumption has also increased and the comfort level of high-rise houses is about 10–21% higher than that of cold regions. The comfortable temperature range in these different cities is between 20°C and 29°C. We have showed the difference between the observed values and the model simulations (model bias) for HDD and CDD in cold and hot regions of China and Africa. This model represents spatial patterns and scales observed in Harbin, Shenzhen and South Africa. These features are characterized by an increased north-south gradient in eastern China, a topographically dependent distribution in western China and an associated increase in average temperature. The most commonly used types of heating in residential areas are heat pumps (31%) and district heating (21%). This is also the preferred case for condensing boilers (17%). In non-residential areas, heat pumps (32%), district heating (27%) and condensing boilers (11%) are the most commonly used heating systems. The total energy demand in Africa and China will be increased from 2020 to 2050. It is expected that the total demand for primary energy in China will be 8770 Mtoe in 2050, which corresponds to an increase in demand for primary energy of 1.9%, while Africa will see an increase of 2.7%. Final energy consumption in China and Africa will be 5776 Mtoe and 970 Mtoe respectively.

Application of Building Intelligent Design in Energy Saving and Sustainable Development

With the rapid development of social and economic development, people's living standards to a certain extent has been continuously improved, building energy consumption further shows a trend of sustained growth, the apparent contradiction in the supply of energy resources in our country further aggravated. In order to the sustainable development of mankind, we must effectively reduce the energy consumption, and further implement the building energy conservation measures into practice. To a certain extent, effective control of building energy consumption, and further alleviate the contradiction between China's energy supply and economic and social development. Let building energy-saving design in China's energy saving and emission reduction to make the necessary contribution. China is a populous country, per capita resources are poor, people's overall average standard of living is low. With the deepening of China's reform and opening up, the Chinese people are gradually getting richer and richer, the Chinese people began to continuously improve their material life, especially the living environment, so China's construction business is also rapidly developing, with the increase of a large number of new buildings, the building energy consumption is growing rapidly. However, China's large population, the energy situation is not optimistic, reduce building energy consumption is the implementation of the scientific concept of development, to achieve sustainable development of the major strategic initiatives.

Assessing energy saving potential of wavelength-dependent passive daytime radiative cooler implemented with EnergyPlus by a roof model

The Passive Daytime Radiative Cooler (PDRC) exhibits potential in enhancing building energy conservation due to its high emissivity in wavelength between 8 μm and 13 μm. However, current building energy simulation programs, e.g., EnergyPlus, generally adopt a constant emissivity. To implement the wavelength-dependent PDRC model into EnergyPlus, a roof model was introduced to couple it with EnergyPlus to assess the energy saving potential of PDRC more reasonably. To assess the PDRC roofs, the impact of buildings constructed in different eras, building heights, and climatic conditions in China on building energy saving was investigated. The results showed that more energy was saved in regions with high cooling demands e.g., Shanghai and Guangzhou. Applying PDRC on roofs of buildings constructed pre 2001 in severe cold regions increased building energy consumptions. Furthermore, buildings with well insulated roofs coated by PDRC were not equally beneficial for reducing cooling demands in summer compared to buildings with non-insulated roofs, but heating demands in winter could be reduced. With an increase in building height, the energy saving potential of PDRC roofs was reduced. Therefore, a comprehensive analysis was imperative considering the local climates as well as the building itself when PDRC is to be applied.

Scheme Design and Energy-Saving Optimization of Cold and Heat Energy Supply System for Substation Main Control Building in Cold Area

In the context of global climate change, the implementation of building energy conservation and carbon reduction, as well as the realization of zero-energy buildings, is a key measure to cope with climate change and resource depletion. A substation is an indispensable building in the process of urbanization construction. However, in existing cold areas, the heating form of substations generally adopts electric heating, which consumes a large amount of energy. This paper optimizes the existing HVAC form of substations through the rational utilization of surrounding environmental resources and puts forward reasonable building energy-saving and carbon-reduction methods. It demonstrates the feasibility of combining solar photovoltaic power generation systems, air source heat pumps, and natural ventilation to optimize energy savings and carbon reduction in the main control building of a substation in a cold area. The computational fluid dynamics (CFD) method is used to demonstrate the feasibility of natural ventilation during the summer and transition seasons. The data indicate that the installation of a solar photovoltaic power generation system results in an average annual power generation of 18.75 MWh. Additionally, using an air source heat pump can save 44.5% of electricity compared to electric heating. When both a solar photovoltaic power generation system and an air source heat pump are used to provide a building with cold and heat sources, the annual emissions of CO2 can be reduced by 4.90 tons compared to a traditional electric heating system.

Modeling and optimization of a passive building HVAC system based on improved PSO and H-J Algorithm

Passive buildings employ the principles of active optimization and passive priority to demonstrate their energy-saving, comfortable, and cost-effective qualities, thereby addressing energy consumption in an efficient manner. However, it cannot be ignored that the Heating Ventilation Air Conditioning (HVAC) system is still the largest energy consumer, especially when it is necessary to maintain the comfort of the indoor environment. Consequently, the control and optimization of the HVAC system is a research hotspot and a challenge in the field of building energy conservation, as it is the key to achieving ultra-low energy consumption operation in passive buildings while ensuring the thermal comfort of the indoor environment. This paper presents a comprehensive modeling, control, and optimization framework for the efficient operation of HVAC systems in a passive building located in Jinan, China. Firstly, the HVAC system is modeled using the transient system simulation tool (TRNSYS), GenOpt, Java, and other software. Secondly, the HVAC system’s year-round operation is simulated using specific configurations. In order to enhance the energy-saving effect, a strategy of increasing heat storage and return air ducts was proposed, and a significant energy-saving effect (approximately 17.31%) was realized. Lastly, the data communication interface with GenOpt is established utilizing the TRNOPT module, a method for actively optimizing the refrigerant temperature is proposed, and recalculation and optimization are carried out utilizing the swarm intelligence algorithm and the pattern search algorithm (Hooker-Jeeves algorithm, H-J algorithm). The final optimization results demonstrate a 19% reduction in energy consumption relative to the baseline heat recovery model, validating the applicability of the optimization method under this strategy. The control and optimization method of the HVAC system proposed in this paper can further exploit the energy-saving potential of the passive building HVAC system and will contribute to the advancement of building energy conservation.

Highly Optically Selective and Thermally Insulating Porous Calcium Silicate Composite SiO2 Aerogel Coating for Daytime Radiative Cooling.

Daytime radiative cooling technology offers a low-carbon, environmentally friendly, and nonpower-consuming approach to realize building energy conservation. It is important to design materials with high solar reflectivity and high infrared emissivity in atmospheric windows. Herein, a porous calcium silicate composite SiO2 aerogel water-borne coating with strong passive radiative cooling and high thermal insulation properties is proposed, which shows an exceptional solar reflectance of 94%, high sky window emissivity of 96%, and 0.0854 W/m·K thermal conductivity. On the SiO2/CaSiO3 radiative cooling coating (SiO2-CS-coating), a strategy is proposed to enhance the atmospheric window emissivity by lattice resonance, which is attributed to the eight-membered ring structure of porous calcium silicate, thereby increasing the atmospheric window emissivity. In the daytime test (solar irradiance 900W/m2, ambient temperature 43 °C, wind speed 0.53 m/s, humidity 25%), the temperature inside the box can achieve a cooling temperature of 13 °C lower than that of the environment, which is 30 °C, and the theoretical cooling power is 96 W/m2. Compared with the commercial white coating, SiO2-CS-coating can save 70 kW·h of electric energy in 1 month, and the energy consumption is reduced by 36%. The work provides a scalable, widely applicable radiative-cooling coating for building comfort, which can greatly reduce indoor temperatures and is suitable for building surfaces.

Mass transfer research on the regeneration process of an air-conditioning battery system

Developing a sustainable and low-carbon society calls for energy conservation of buildings. On this purpose, green air-conditioning systems driven by renewable energy have been encouraged as alternative to the present vapor-compression air-conditioning system. Absorption system is one promising representative, but relatively lower performance impedes its application. To improve, we propose an air-conditioning battery system (ACBS) that evolves from the traditional absorption system. Its COP attains four by incorporating a refrigeration cycle with a battery cycle, realizing energy storage when producing cooling effect. Driven by renewable energy, ACBS is a green air-conditioning system for being environmental friendly with refrigerant water and avoiding the combustion of fossil fuels that emits a large amount of CO2 bringing in environmental issues. The critical part of ACBS is the capacitive deionization (CDI) regeneration process, which concentrates absorbent by electrical adsorption. The mass transfer mechanism of regeneration is important for system optimization. Simulation investigation has been made in this paper to reveal the mechanism. A two-dimensional model has been established and validated to depict the dynamic response at different electric adsorption stages. Analysis has been conducted based on the models to expose the influence of some critical parameters. The results show that the enhancement of COP could exceed 50% with optimum design parameters.

City-level building operation and end-use carbon emissions dataset from China for 2015–2020

sThe building sector, which accounts for over 20% of China’s total energy-related carbon emissions, has great potential to reduce emissions and is critical to achieving China’s emissions peak and carbon neutrality targets. However, the lack of data on operational carbon emissions and end-use carbon emissions in the building sector at the city level has become a major barrier to the development of building energy conservation policies and carbon peaking action plans. This study uses a combination of “top-down” and “bottom-up” methods to account for the operational carbon emissions of buildings in 321 cities in China from 2015 to 2020. The energy consumption in buildings is further broken down into six end uses: central heating, distributed heating, cooking and water heating (C&W), lighting, cooling, appliances and others (A&O). The dataset can serve as a reference to support city-level policies on peak building emissions and is of great value for the improvement of the carbon emissions statistical accounting system.