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[Display omitted] • 55.60% (free radicals) and 44.40% (nonradical) contributions without sulfoxides probe. • 39.09% (free radicals) and 60.91% (nonradical) contributions with sulfoxides probe. • PMSO transformed the mechanism from free radical dominated to nonradical dominated. • PMSO improve the utilization efficiency of Fe(II) and redox reaction between Fe(Ⅱ) and PS. • Sulfoxides selectively enhanced degradation pollutants with an IP lower than 8.66 eV. Sulfoxides are widely recognized as probes for identifying and evaluating the generation and contribution of high-valent metals in advanced oxidation processes. However, this paper was surprising to find that the presence of sulfoxides selectively enhanced the degradation of specific pollutants in the Fe(II)/PS system. Represented by methyl phenyl sulfoxide (PMSO), scavenging experiments for active species showed that the presence of PMSO transformed the mechanism from radical dominated (55.60 %) to nonradical dominated (60.91 %), greatly improving the anti-interference ability of the system. Determining the concentration of Fe(Ⅱ) and total iron (Fe tot) in solution revealed that the presence of PMSO improved the utilization efficiency of Fe(II) and PS by enhancing the redox reaction between Fe(II) and PS, and resulted in the generation of Fe(IV) more favorably than the generation of SO 4 ·− and ·OH. Additionally, comparing the proven high-valent iron dominated Fe(II)/PI system with the free radical dominated Fe(II)/PS system of this paper, it was revealed that the selectively enhanced oxidation of PMSO specifically targets the free radical dominated system. Experiments have shown that the degradation of acetaminophen, ibuprofen, phenol, and p-chlorophenol was enhanced by PMSO, while the degradation of norfloxacin, primidone, chloramphenicol, sulfamethoxazole, p-nitrophenol, benzoic acid, and nitrobenzene was inhibited. Based on density functional theory (DFT) calculations, PMSO has a selectively enhanced degradation effect for organic pollutants with ionization potential (IP) below 8.66 eV, and vice versa, it has an inhibitory effect. The present study provides new insights into the contribution of sulfoxide to the assessment of high-valent metals and sheds new light on the mechanism of active species. [ABSTRACT FROM AUTHOR]

Three air-stable zirconocene perfluoro-octanesulfonates were successfully synthesized by treatment of C 8 F 17 SO 3 Ag with (RCp) 2 ZrCl 2 [R = H, n -Bu, t -Bu]. According to X-ray analysis, they have μ 2 -hydroxyl bridged cationic binuclear structures: ( i ) [CpZr(OH 2 ) 3 ] 2 ( μ 2 -OH) 2 (OSO 2 C 8 F 17 ) 4 ·2THF·4H 2 O ( 1a ·2THF·4H 2 O), ( ii ) [ n -BuCpZr(OH 2 ) 3 ] 2 ( μ 2 -OH) 2 (OSO 2 C 8 F 17 ) 4 ·6H 2 O ( 2a ·6H 2 O), and ( iii ) [ t -BuCpZr(OH 2 ) 3 ] 2 ( μ 2 -OH) 2 (OSO 2 C 8 F 17 ) 4 ·2C 3 H 6 O·8H 2 O ( 3a ·2C 3 H 6 O·8H 2 O). The ligands of water and organic molecules in the complexes originated from the moist air and solvent during their recrystallization. These complexes were characterized with different techniques, and found to show water tolerance, air/thermal stability as well as strong Lewis acidity. Moreover, the complexes showed highly catalytic activity in various reactions of C C bond formation. With good recyclability, they should find wide applications in organic chemistry. [ABSTRACT FROM AUTHOR]

Pipe-embedded concrete radiant floor system has gained much popularity due to its higher energy efficiency and better thermal comfort. Simplified yet accurate heat transfer models are essential for energy simulation of this system. This study presents the development and validation of a simplified RC-network model for the pipe-embedded concrete radiant floors. A concrete radiant floor mainly consists of three parts which are the cover layer, the pipe-embedded concrete slab and the insulation layer. The cover layer and the insulation layer are simplified as one-dimensional and represented by RC models with two resistances and one capacitance (2R1C). Within the pipe-embedded concrete slab, the complex heat transfer is represented by a coupled RC model which includes two parts describing the heat transfers of the concrete slab and the water loop respectively. In the case studies, the coupled RC model for the pipe-embedded concrete slab has been validated in both numerical and experimental ways. The experimental validation results show that the average relative errors of the coupled RC model in predicting the upper and bottom surface heat fluxes are all less than 5.5%. Validation has also been conducted to demonstrate the accuracy and effectiveness of this developed simplified RC-network model in predicting the dynamic thermal performance of a multi-layer pipe-embedded concrete radiant floor. The developed simplified RC-network model can be beneficial for design and optimal control of the pipe-embedded concrete radiant floor system. [ABSTRACT FROM AUTHOR]

A novel sensitive electrochemical sensor based on a glassy carbon electrode (GCE) modified with molecularly imprinted polymer (MIP) and grapheme oxide (GO) was developed. The MIP/GO material was prepared by precipitation polymerization in the presence of sulfanilamide as template molecule. The MIP/GO based electrochemical sensor was characterized using scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV). The results indicated that the sensor exhibited good affinity and excellent electrochemical response for sulfanilamide. Under optimized conditions, the oxidation peak current intensity of sulfanilamide showed two linear dynamic ranges from 10 to 1000 ng mL −1 , and the standard deviation was less than 5% using SWV method. The sensor displays good stability, reproducibility, and high sensitivity. It can be further applied to quantify sulfanilamide in milk. [ABSTRACT FROM AUTHOR]

The study proposes a new low-grade energy utilization system, i.e. a pipe-embedded wall integrated with ground source-coupled heat exchanger, and investigates its energy saving potentials in five typical climate regions of China. The cool/hot water produced by the ground source-coupled heat exchanger is supplied to the pipe-embedded wall to intercept the heat gain/loss through the wall. A real-scale building energy simulation platform has been developed for estimating the energy saving potentials. The study results show that the energy saving potential of the proposed system varies with the climate regions. With the same sized pipe-embedded wall system, the building in warm climate regions achieves the largest energy saving percentage. It is followed by the buildings in the hot summer and cold winter climate region, the severe cold climate region, the cold climate region, and the hot summer and warm winter climate region in the declining sequence of energy saving. Meanwhile, a multi-criteria performance evaluation has been conducted to search for the optimal size of the low-grade-energy system in each climate region. The proposed system can be utilized in practice for energy saving, and the study results are helpful in guiding the practical applications of the pipe-embedded wall system in different climate regions. [ABSTRACT FROM AUTHOR]

Hollow blocks or bricks are widely used due to the good thermal insulation, lightweight, acoustic insulation, etc. This paper presents the development of a simplified heat transfer model of hollow block for simple and efficient heat flow calculation. This model is developed based on parameter identification in frequency domain by using finite element method in frequency domain. Firstly, the frequency domain finite element model (FDFEM) of the hollow block is developed by using finite element method in frequency domain to obtain the theoretical frequency characteristics of this structure. Then, the heat transfer function model in the form of s -polynomial (i.e., the s -polynomial heat transfer function model) is identified by using a parameter identification procedure based on the calculated theoretical frequency thermal characteristics. Finally, the simplified heat transfer model, i.e., the Conduction Transfer Function (CTF) coefficients, of this hollow block are derived from the identified s -polynomial heat transfer function model. A case study is presented for the prediction of the dynamic heat transfer of this hollow block by using the simplified heat transfer model. The predicted dynamic heat transfer of this block is validated by experimental data. [ABSTRACT FROM AUTHOR]

As one kind of clean and widely distributed unconventional energy resource, natural gas hydrate (NGH) is attracting increasing attention these years. In this study, the methods of depressurization and thermal stimulation are adopted to dissociate the NGH experimentally, when the initial temperature is 1.0 °C, the initial pressure is 3.1 MPa, the porosity is 0.35 and initial NGH saturation is 32%. The results reveal that during the depressurization process, there exists a pressure difference threshold (Δ P = 0.19 MPa), and similarly a temperature difference threshold (Δ T = 1.4 °C) exists during the process of thermal stimulation. NGH will not dissociate until pressure difference or temperature difference outweighs the corresponding threshold value. In addition, the influencing factors of driving force on the gas production performance have been studied. When thermal stimulation is adopted, the driving force of the temperature difference will grow with the increasing hot-brine injection rate and the brine temperature, in which case the gas production rate will drive up. When depressurization is used, the pressure difference driving force will go up with the increasing depressurizing range and depressurizing rate. Driving force is a major factor during NGH dissociation by depressurization and thermal stimulation. [ABSTRACT FROM AUTHOR]

SnS is an important semiconductor and its performance depends greatly on its morphology and 3D architecture. So the synthesis for it with specific structures has been widely paid attention. Herein, a novel hollow nanoparticle-based SnS crystal product with microcluster-like 3D network hierarchitectures was developed, via a template-assisted solvothermal route in diethylene glycol (DEG) solvent, followed by annealing in N 2 atmosphere and subsequent corrosion of template by dilute acid. CaCO 3 nanoparticles were used as the template, SnCl 2 as the tin source, thiourea and l -cysteine hydrochloride monohydrate (Cys) as two different sulfur sources for a comparison study. Results show that successful fabrication of the hollow-structured SnS product mentioned above was achieved only in the case of using Cys as the sulfur source, mainly due to much stronger adhesion of Cys on CaCO 3 template and microcluster-like stacking patterns of CaCO 3 nanoparticles in DEG solvent. This novel 3D hierarchical SnS product owns 1–5 times higher specific surface area, unique hollow nanostructure units with rich mesopores inside the shells, and scattering-enhanced absorption in UV–vis light region, as against those previously reported micro-scale tin sulfide 3D hierarchitectures assembled by nanopetals, nanosheets, nanorods, nanobelts, etc. So it should have much more extensive and promising applications. [ABSTRACT FROM AUTHOR]

Active pipe-embedded building envelope is a new kind of external building wall or roof which usually has pipes embedded in it to let water circulate in these pipes for heat transfer. This structure may effectively intercept the heat/coolth from the ambient environment to indoor space and provide extra space conditioning for the indoor space. Frequency-domain finite-difference (FDFD) model can predict the frequency thermal response of active pipe-embedded building envelope directly and provide some important guidelines for system control and system sizing. This paper presents the experimental validation of this model in time domain by using Fourier series analysis. An experiment test rig was developed for the thermal response measurements of the pipe-embedded building envelope under pre-defined conditions. First, the measured time series of surface temperatures are transformed into complex Fourier series by using Discrete Fourier Transform and applied into the FDFD model as the boundary condition for calculation. Then, the calculated frequency thermal responses by FDFD model can be easily transformed into time series by using Inverse Discrete Fourier Transform. Finally, the time-domain thermal responses of FDFD model are obtained. The results show that the calculated time-domain thermal responses of the active pipe-embedded building envelope by using FDFD model agree well with the experimental measurements. [ABSTRACT FROM AUTHOR]

Active pipe-embedded building envelope is a new kind of pipe-embedded building external wall/roofs. Usually, pipes are embedded in the wall slab or roof slab to allow water circulating in these pipes for heat transfer. Low-grade energy sources can be used for this structure since the enlarged heat transfer surface between the slab mass and water in the pipe allowing for substantial heat flow for relatively small temperature difference. This structure may reduce building cooling/heating load and improve indoor thermal comfort by intercepting the heat/coolth from the ambient air to indoor space. This paper presents a semi-dynamic model of this structure for thermal performance evaluation for system design or indoor environment control etc. This semi-dynamic model is a coupled model. The first part is a simplified dynamic RC model (i.e., resistance and capacitance model). The heat transfer along the width of this structure can be predicted easily by the RC model. The second part is a classical NTU model for evaluating the heat transfer along the pipe and total heat transfer on both surfaces of this structure. A CFD model is developed to act as a virtual experimental test rig to simulate the thermal characteristics of this structure. The simulated results are used to validate this semi-dynamic model and its performance prediction. [ABSTRACT FROM AUTHOR]

Highlights: [•] A review on the development and modeling of active hollow core slab is presented. [•] The applications and performance evaluation of the slab in building are reviewed. [•] Finite element or finite difference method is often used in multidimensional model. [•] Performance evaluations of building using active slabs for ventilation are limited. [•] More works on the active hollow core slab are worthwhile. [ABSTRACT FROM AUTHOR]

Abstract: Active pipe-embedded building envelope is a new building envelope, which is an external wall or roof with pipes embedded in it. This structure has the advantages to utilize directly low-grade energy sources for reducing building cooling/heating load and improving indoor thermal comfort. This structure may also use some phase change materials (PCM) to be pasted as a thin layer for further enhancing these benefits. This paper presents a dynamic simplified thermal model of this structure with the thermal network structure of lumped thermal mass, and the parameter identification of the simplified model based on frequency characteristic analysis. These resistances and capacitances are identified in frequency domain by using generic algorithm (GA) by comparing the frequency characteristics of the simplified model with the theoretical frequency characteristics of this structure obtained with Frequency-Domain Finite Difference (FDFD) method. Firstly, the FDFD model of this structure is established, and the theoretical frequency characteristics under various disturbances are calculated for the reference of parameter identification. Then, an equivalent dynamic simplified thermal model with lump thermal network structure is developed, and its frequency characteristics are also deduced and calculated. Finally, GA estimator is used to identify these parameters of the simplified model for allowing the frequency responses of the simplified model to match the theoretical frequency responses by using FDFD method. Various case studies are presented to validate the accuracy of the simplified models and the effectiveness of the parameter identification for the model. [Copyright &y& Elsevier]

Abstract: Carbon black supported ultra-high loading silver nanoparticle catalyst (Ag/C) was prepared by a modified ethylene glycol reduction method. The thermogravimetry analysis showed that the Ag mass loading of this catalyst reached up to 392wt.%. The X-ray diffraction and scanning electron microscopy characterizations showed that the Ag nanoparticles were ca. 10nm diameter of fine spheres with a face-centered cubic crystal structure, and were densely stacked but not aggregated on the carbon black surface in spite of such ultra-high loading and small size. The chronoamperometry and polarization studies utilizing rotating disk electrode (RDE) or rotating ring disk electrode (RRDE) revealed that this ultra-high loading 392wt.% Ag/C catalyst exhibited higher electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline medium. The ORR proceeded a four-electron process when compared with the low loading 40wt.% Ag/C catalyst. Furthermore, the chronopotentiometry test on gas-diffusion electrode containing the 392wt.% Ag/C catalyst implied that this catalyst had a considerably stable ORR activity for application in brine electrolysis. [Copyright &y& Elsevier]

Abstract: Sulfosalicylic acid (C7H6O6S) as a special additive was applied to favor the deposition of pure zinc sulfide (ZnS) nanocrystal thin films on ITO substrates from acidic solutions by potentiostatic technique with subsequent annealing. XRD, EDX, Raman, SEM and UV–vis–NIR analyses demonstrate that a proper concentration of C7H6O6S additive (0.2mM) in the electrolyte containing 20mM Zn2+, 20mM S2O3 2−, 0.375mM SO3 2− and 200mM LiCl can greatly contribute to the controllable growth of pure cubic ZnS film along (200) orientation at potential of −1.1V vs. SCE. The film possesses a uniform surface with an average crystallite size ca. 40.9nm, and a band gap ca. 3.68eV. Electrochemical studies indicate that C7H6O6S could adsorb on ITO surface and act as a hydrogen bond donor for free Cl−. The adsorption of C7H6O6S blocks some active sites used for the deposition of S, while the role of hydrogen bond donor promotes the deposition of Zn element by decreasing the concentration of [ZnCl4]2− and increasing the concentration and mobility of Zn2+ in electrochemical double layer. Consequently, the addition of C7H6O6S narrows the deposition potential gap of S and Zn elements in the range of −1.0 to −1.2V, thus resulting in their co-deposition to form pure ZnS. [Copyright &y& Elsevier]

Abstract: Zinc sulfide (ZnS) semiconductor nanocrystal films have been prepared on indium tin oxide coated glass substrates by sulfosalicylic acid (C7H6O6S)-assisted galvanostatic deposition with subsequent annealing. The deposition was performed at 10mAcm−2 in acidic electrolytes containing 15–30mM Zn(CH3COO)2, 20mM Na2S2O3, 200mM LiCl, 0.375mM Na2SO3, and 0 or 0.2mM C7H6O6S. Results show that the presence of C7H6O6S can suppress the precipitation of Zn and S impurity phases during the ZnS deposition process. As the [C7H6O6S]=0.2mM and [Zn2+]=20mM, the deposited ZnS film exhibits only hexagonal structure with an ideal Zn/S atomic ratio of 1.03 and a close-packed granular morphology. But its band gap about 2.86eV is narrower than the common value of ZnS, probably due to the existence of some spurious acetate species and defect states. By annealing the film at 400°C for 60min, its band gap increased up to 3.70eV, despite that its crystalline phase transformed into cubic structure which usually shows the narrower band gap than hexagonal ZnS. The significant band gap widening could be ascribed to the degradation of spurious acetate species and the reduction of various possible defect states in the annealing process. [Copyright &y& Elsevier]

Abstract: Low-grade energy sources such as geothermal energy, favorable ambient air and industrial waste heat etc. exist widely. Sufficient utilization of these low-grade energy sources may reduce our daily dependence on high-grade energy sources such as electricity resulting in reduced emission of green house gas for environmental conservation. Active pipe-embedded structure as floor/ceiling usually with water as the medium to carry heat or coolth may utilize these low-grade energy sources for providing space air-conditioning. Compact arrangement of pipes in the structure may significantly enlarge heat transfer surface between the slab mass and water in the pipe allowing substantial heat flows even for relatively small temperature differences. Application of the heat or coolth storage capacity of this structure for preheating or pre-cooling is also one among the advantages of this structure for shifting load and exploiting the nighttime cheap electricity tariff in some regions. This paper presents the technology of the active pipe-embedded structure for utilizing widely existing low-grade energy sources following by a comprehensive review on the heat transfer calculation models of this structure and its practical applications in real building systems for space air-conditioning. This review shows that more works on the active structure, especially simple and transient models for dynamic and accurate performance prediction and easy integration with existing building energy simulation packages, are worthwhile for further promoting the practical application wherever the low-grade energy sources are favorable. [ABSTRACT FROM AUTHOR]

Abstract: A functionalized copper-containing ordered mesoporous carbon (Cu-OMC) which shows good electrical properties was synthesized by carbonization of sucrose in the presence of cupric acetate inside SBA-15 mesoporous silica template. Based on this, a facilely fabricated amperometric biosensor by entrapping laccase into the Cu-OMC/chitosan (CS) film was developed. Laccase from Trametes versicolor was assembled on a composite film of Cu-OMC/chitosan (CS) modified Au electrode and the electrode was characterized. The optimum experimental conditions of biosensor for the detection of catechol were studied in details. Under the optimal conditions, the detection limit was 0.67μM and the linear detection range was from 0.67μM to 15.75μM for catechol. The apparent Michaelis–Menten (K M app) was estimated using the Lineweaver–Burk equation and the K M app value was 40.2μM. This work demonstrated that the Cu-OMC/CS composite provides a suitable support for laccase immobilization and construction of biosensor. [Copyright &y& Elsevier]

Abstract: The effect of potassium hydrogen phthalate (C8H5KO4) as a special additive on the one-step electrodeposition of single-phase CuInS2 thin films from acidic solution (pH 2.5) was investigated in detail. The XRD, SEM and UV–vis–NIR characterization confirms that the addition of an adequate concentration of C8H5KO4 (23mM) to the electrolytic bath containing 12.5mM Cu2+, 10mM In3+, 40mM S2O3 2− and 100mM LiCl can contribute greatly to the controllable growth of pure chalcopyrite CuInS2 films with uniform surfaces and an ideal band gap of approximately 1.54eV. Complexation studies of C8H5KO4 with Cu2+ and In3+ in electrolytic solutions indicated that C8H5KO4 can complex Cu2+ more strongly than In3+ and move the electrode potentials of Cu2+ and In3+ near each other as determined by polarization analysis. Furthermore, the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analysis performed in a series of solution systems revealed a three-step reaction mechanism for CuInS2 deposition and considerable adsorption of C8H5O4 − and Cu(C8H5O4)+ to the cathode surface. This deposition shows that the synergetic effects of complexation and adsorption originated from the additive on the Cu2+ electro-reduction, thus promoting the co-deposition of copper, indium and sulfur in the form of single-phase CuInS2. [Copyright &y& Elsevier]

Abstract: A composite coating which could control drug release and biocorrosion of magnesium alloy stent materials WE42 was prepared. This composite coating was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy, WE42, by mixing different degrees of cross-linked gelatin with well-dispersed poly(dl-lactide-co-glycolide) (PLGA) nanoparticles. The PLGA nanoparticles were prepared by emulsion solvent evaporation/extraction technique. Nano ZS laser diffraction particle size analyzer detected that the size of the nanoparticles to be 150–300nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) was used to analyze the morphology of the nanoparticles and the composite coating. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of the composite coating. Drug release was determined by ultraviolet–visible (UV–vis) spectrophotometer. The corrosion resistance of the composite coating was improved by preventing the corrosive ions from diffusing to the MAO films. The drug release rate of paclitaxel (PTX) exhibited a nearly linear sustained-release profile with no significant burst releases. [Copyright &y& Elsevier]

Abstract: The mesoporous silica sieve MCM-41 containing methylene blue (MB) provides a suitable immobilization of biomolecule matrix due to its uniform pore structure, high surface areas, good biocompatibility and nice conductivity. Based on this, a facilely fabricated amperometric biosensor by entrapping laccase into the MB modified MCM-41/PVA composite film has been developed. Laccase from Trametes versicolor is assembled on a composite film of MCM-41 containing MB/PVA modified Au electrode and the electrode is characterized with respect to transmission electron microscopy (TEM) and scanning electron microscopic (SEM), Cyclic voltammetry (CV), response time, detection limit, linear range and activity of laccase. The laccase modified electrode remains good redox behavior in pH 4.95 acetate buffer solution, at room temperature in present of 0.1 mM catechol. The response time (t 90%) of the modified electrode is less than 4 s for catechol. The detection limit is 0.331 µM and the linear detect range is about from 4.0 µM to 87.98 µM for catechol with a correlation coefficient of 0.99913(S/N =3). The apparent Michaelis–Menten (KM app ) is estimated using the Lineweaver–Burk equation and the KM app value is about 0.256 mM. This work demonstrated that the mesoporous silica MCM-41 containing MB provides a novel support for laccase immobilization and the construction of biosensors with a faster response and better bioactivity. [Copyright &y& Elsevier]

Abstract: Catalytic dechlorination of para-nitrochlorobenzene (p-NCB) by Ni/Fe (nickel/iron) bimetallic nanoparticles was carried out. The catalytic reduction and dechlorination reaction was believed to take place on the surface site of the nanoscale catalysts. In the reaction, Ni plays a role of catalyst decreasing activation energy of hydrogenolysis of C–Cl bonds and the Fe was corroded to produce hydrogen gas. 100% dechlorination efficiency was achieved for particles with 2.0% Ni, in contrast, just 51% chlorine was obtained for particles with 0.5% Ni at the Ni/Fe nanoparticles mass concentration of 6 g l−1 used after 300 min reaction. The p-NCB was first adsorbed by nanoparticles completely then quickly reduced to p-chloroaniline (p-CAN) and aniline (AN), and p-CAN was detected as an intermediate. As expected, with the Ni/Fe addition and the Ni loading percentage over Fe increasing, the temperature going up, and the pH decreasing, the dechlorination efficiency increased. The Ni/Fe catalytic reductants showed prominent activity to the reductive catalytic dechlorination of p-NCB at ambient temperature and pressure as well as high removal efficiency of p-NCB and p-CAN in agricultural pesticide wastewater, therefore, they could be good choices for remediation of contaminated groundwater. [Copyright &y& Elsevier]

Abstract: The aqueous phase oxidation of gaseous elemental mercury (Hg0) by potassium persulfate (K2S2O8, KPS) catalyzed by Ag+ and Cu2+ was investigated using a glass bubble column reactor. Concentrations of gaseous Hg0 and aqueous Hg2+ were measured by cold vapor generation atomic absorption spectrometry (CVAAS). The effects of several experimental parameters on the oxidation were studied; these include different types of catalysts, pHs and concentrations of potassium persulfate, temperatures, Hg0 inlet concentrations and tertiary butanol (TBA). The results showed that the removal efficiency of Hg0 increased with increasing concentration of potassium persulfate and catalysts Ag+, Cu2+ and Ag+ provided better catalytic effect than Cu2+. For example, in the presence of 5.0mmoll−1 KPS, the mercury removal efficiency could reach 75.4 and 97.0% for an Ag+ concentration of 0.1 and 0.3mmoll−1, respectively, and 69.8 and 81.9% for 0.1 and 0.3mmoll−1 Cu2+. On the other hand, high temperature and the introduction of TBA negatively affect the oxidation. Furthermore, the removal efficiency of Hg0 was much greater in neutral solution than in either acidic or alkaline solution. But the influence of pH was almost eliminated upon the addition of Ag+ and Cu2+, and high Hg0 inlet concentration also has positive impact on the removal efficiency of Hg0. The possible catalytic oxidation mechanism of gaseous mercury by KPS was also proposed. [Copyright &y& Elsevier]

Abstract: Poly(ethylene-co-octene) (POE) was mixed into polypropylene (PP) by an internal mixer, which was installed on on-line small-angle laser light scattering (SALLS) device. A new parameter called the thickness (d) of transition layer was introduced to describe the compatibility of PP/POE blends in both dynamic and static states. Using the correlation distance, a c (it was indicative of the dimension of the dispersed phase pellets), d was calculated for the PP/POE blends based on the SALLS theory. The results indicated that the average values of d increased with increasing concentration of dispersed phase and had a maximum value at 40/60(PP/POE) for the blends. And the values of d showed much more violent fluctuation and were much larger at the early stage of mixing, but at a later stage d leveled off and approached to steady state. In addition, the relationships between the thickness of transition layer and mechanical properties were studied. It showed that the notched Izod impact strength and the average values of d of PP/POE blends increased with increasing of POE concentration, while the Young''s modulus and flexural modulus decreased. The results indicated that SALLS method was an effective method to deal with diffuse transition layer of PP/POE blends and d was indeed a valid parameter to describe compatibility. [Copyright &y& Elsevier]

Abstract: This paper presents a simple time domain calculation method to derive thermal response factors and conduction transfer conduction (CTF) coefficients of finite differential models for estimating transient heat transfer through building structures. It is developed on the basis of converting the matrix exponential function, which is a part of the solution of the state equation established from the finite differential equations of building finite differential models, to matrix polynomial. The thermal response factors and CTF coefficients can be easily derived from the matrix polynomial with simple arithmetic and integral in time domain. This method avoids the time-consuming root-finding process of conventional methods and the computation of all the internal temperature of the finite differential model, while utilizing the advantage of the thermal response factors/CTF coefficients which relate the desired outputs at a moment to the previous inputs through a set of coefficients. Various case studies were conducted to validate the performance of this time domain calculation method in calculating the thermal response factors and CTF coefficients of various order finite differential models. [Copyright &y& Elsevier]

Abstract: An alternative simplified building model is developed to describe existing building system aiming at providing performance benchmark for performance evaluation and diagnosis at building level and performance prediction for air-conditioning system optimal control. This model combines detailed physical models of building envelopes and a thermal network model of building internal mass. The detailed physical models are the CTF (Conduction Transfer Function) models of building envelopes based on the easily available detailed physical properties of exterior walls and roof. The thermal network model is the 2R2C model, and its parameters are estimated and optimized using genetic algorithm with short-term monitored operation data. The parameter optimization of the simplified building internal mass model (2R2C) and the simplified dynamic building model (i.e., model) are validated in a high-rising commercial office building under various weather conditions. This model is an alternative modeling approach for simulating the overall building dynamic thermal performance when CTF model is chosen to model the building envelope. [Copyright &y& Elsevier]

Abstract: The morphological evolution during extrusion and rheological properties of polypropylene (PP) and ethylene–octene copolymer (EOC) blends were studied. The phase morphology of the blends at different locations along the extruder length was investigated by scanning electron microscopy (SEM). The PP/EOC (70/30) blends has already formed a well-established droplet/matrix morphology at Valve 3, and an elongation of particles was observed from Valve 3 to extruder die. The phase-separated PP/EOC blends within the linear viscoelastic regime display higher than expected values of storage modulus at low frequencies. The effect of the deformation of phase domain on the rheological properties of the blends, the small constant strain amplitude within the linear viscoelastic regime does not substantially alter the droplet shape of the dispersed phase and yields a linear viscoelastic response, but the large strain amplitude destroys the dispersed phase domains, and eventually results in shear-induced mixing or homogenization. [Copyright &y& Elsevier]

Abstract: Simple and effective building energy models are essentially needed for many applications, such as building performance diagnosis and optimal control, etc. The energy model involves two important parts of building components, i.e., building envelopes and building internal mass. This paper presents a methodology for parameter optimization of 3R2C thermal network model of building envelopes (composed of three resistances and two capacitances) based on frequency domain regression using genetic algorithm (GA). First, the theoretical frequency characteristics of heat transfer through building envelope are calculated using detailed physical description within the frequency range of concern. Second, the frequency characteristics of the simplified 3R2C model are calculated with random values of individual resistances and capacitances which constrain to total thermal resistance and capacitance. Then, the errors between the theoretical frequency characteristics and the frequency characteristics of the simplified model are calculated. Finally, GA estimator is developed to optimize the parameters of the simplified model, allowing the frequency responses of the simplified model match the actual heat transfer through building envelope the best. Various case studies are conducted also to validate the parameter optimization method of the simplified 3R2C model. The accuracy of simplified models for constructions of different weights is studied. [Copyright &y& Elsevier]

The addition of metal chelates such as Fe(II)EDTA or Fe(II)Cit to wet flue gas desulfurization systems has been shown to increase the amount of NO x absorption from gas streams containing SO2. This paper attempts to demonstrate the advantage of not only using Fe(II)Cit chelate to absorb nitrogen oxides from flue gas but also the advantage gained from adding microorganisms to the system. Two distinct classes of microorganisms are needed: denitrifying and iron-reducing bacteria. The presence of oxygen in flue gas will affect the absorption efficiency of NO by Fe(II)Cit chelate. The oxidation of Fe(II) can be slowed with the help of bacteria in two ways: bacteria can serve to directly reduce Fe(III) to Fe(II) or they can serve to keep levels of dissolved oxygen in the solution low. As a result, after NO absorption, Fe(II)(Cit)NO will be reduced by denitrifying bacteria to Fe(II)Cit while Fe(III) is reduced by anaerobic bacteria back to Fe(II). Our experiments have shown that the implementation of our protocol allowed for an NO reduction rate constant increase from standard levels of 0. 0222–0. 100mMh−1 with inlet NO changed from 250 to 1000ppm. We have also found that total Fe concentration tends to decrease after prolonged periods of operation due to the loss of some Fe to the formation of Fe(OH)3 that settles together with the sludge at the bottom of bioreactor tank. [Copyright &y& Elsevier]

Abstract: A novel technique for enzyme immobilization on the surface of the Au electrode for designing amperometric biosensor by electrospinning poly(vinyl alcohol) (PVA) and glucose oxidase (GOD) is presented in this paper. The immobilized GOD remained active inside the electrospun PVA fibrous membranes. The membranes are promising candidates for immobilization of enzymes because of their high specific surface area and porous structure. The infrared spectrum, the UV–Vis spectrum, and the scanning electronic microscope of the membranes showed that the enzyme had been immobilized inside the PVA membranes. Chronoamperometric measurements demonstrated that electrospun fibrous enzymatic electrodes exhibited a rapid response (1s) and a higher response current (μA level) to glucose in the normal and diabetic level. The linear response range (from 1 to 10mM) and the lower detection limit (0.05mM) of the sensor are satisfying. The electrospun method makes it convenient and efficient to prepare the enzymatic electrode for biosensors. [Copyright &y& Elsevier]

Abstract: Building thermal transfer models are essential to predict transient cooling or heating requirements for performance monitoring, diagnosis and control strategy analysis. Detailed physical models are time consuming and often not cost effective. Black box models require a significant amount of training data and may not always reflect the physical behaviors. In this study, a building is described using a simplified thermal network model. For the building envelope, the model parameters can be determined using easily available physical details. For building internal mass having thermal capacitance, including components such as furniture, partitions etc., it is very difficult to obtain detailed physical properties. To overcome this problem, this paper proposes to present the building internal mass with a thermal network structure of lumped thermal mass and estimate the lumped parameters using operation data. A genetic algorithm estimator is developed to estimate the lumped internal thermal parameters of the building thermal network model using the operation data collected from site monitoring. The simplified dynamic model of building internal mass is validated in different weather conditions. [Copyright &y& Elsevier]

Abstract: Building simple and effective models are essential to many applications, such as building performance diagnosis and optimal control. Detailed physical models are time consuming and often not cost-effective. Black box models require large amount of training data and may not always reflect the physical behaviors. In this study, a method is proposed to simplify the building thermal model and to identify the parameters of the simplified model. For building envelopes, the model parameters can be determined using the easily available physical details based on the frequency characteristic analysis. For the building internal mass involving various components, it is very difficult to obtain the detailed physical properties. To overcome this problem, the building internal mass is represented by a thermal network of lumped thermal mass and the parameters are identified using operation data. Genetic algorithm (GA) estimators are developed to identify these parameters. The simplified dynamic building energy model is validated on a real commercial office building in different weather conditions. [Copyright &y& Elsevier]

Abstract: Chemical treatment of para-nitrochlorobenzene (p-NCB) by palladium/iron (Pd/Fe) bimetallic particles represents one of the latest innovative technologies for the remediation of contaminated soil and groundwater. The amination and dechlorination reaction is believed to take place predominantly on the surface site of the Pd/Fe catalysts. The p-NCB was first transformed to p-chloroaniline (p-CAN) then quickly reduced to aniline. 100% of p-NCB was removed in 30min when bimetallic Pd/Fe particles with 0.03% Pd at the Pd/Fe mass concentration of 3g 75ml−1 were used. The p-NCB removal efficiency and the subsequent dechlorination rate increased with the increase of bulk loading of palladium and Pd/Fe. As expected, p-NCB removal efficiency increased with temperature as well. In particular, the removal efficiency of p-NCB was measured to be 67%, 79%, 80%, 90% and 100% for reaction temperature 20, 25, 30, 35 and 40°C, respectively. Our results show that no other intermediates were generated besides Cl−, p-CAN and aniline during the catalytic amination and dechlorination of p-NCB. [Copyright &y& Elsevier]

Abstract: Nanoscale Pd/Fe bimetallic particles were synthesized and used to hydrodechlorinate 2,4-dichlorophenol. 2,4-dichlorophenol was transformed to phenol with a small amount of 2-chlorophenol and 4-chlorophenol produced. The reaction pathway and reaction rate constants for each step have been determined. The effects of various Pd bulk loadings in the bimetals, temperatures and pH conditions on the hydrodechlorination of 2,4-dichlorophenol were examined. The results showed that higher Pd bulk loadings, higher temperatures and weak acid conditions are beneficial to the catalytic dechlorination of 2,4-dichlorophenol. [Copyright &y& Elsevier]

Abstract: Catalysis dechlorination of chlorinated organic matter by palladium/iron bimetallic particles represents one of the latest innovative technologies for contaminated soil and groundwater remediation. The reaction of dechlorination is believed to take place on the surface site of the catalyst in a pseudo-first-order mode. The dechlorination rate increases with an increase of the bulk loading of palladium due to the increase of both the surface loading of palladium and the total surface area exposed. The results show that no other intermediates were generated besides Cl−, benzene and chlorobenzene during dechlorination of o-dichlorobenzene. [Copyright &y& Elsevier]

Abstract: Three isomers of dichlorobenzene (o-, m- and p-DCB) were dechlorinated by Pd/Fe catalyst in aqueous solutions through catalytic reduction. The dechlorination reaction took place on the surface site of the catalyst via a pseudo-first-order kinetics, and resulted in benzene as the final reduction product. The rate constants of the reductive dechlorination for the three dichlorobenzenes (DCBs) in the presence of Pd/Fe as a catalyst were measured experimentally. In all cases, the reaction rate constants were found to increase with the decrease in the Gibbs free energy of the formation of DCBs. The reaction rate constant for o-, m- and p-DCBs in the presence of 0.020% (w/w) Pd/Fe at 25 °C was determined to be 0.0213, 0.0223, and 0.0254 min−1, respectively. While the activation energy of each dechlorination reaction was measured to be 102.5, 96.6 and 80.0 kJ mol−1 for o-, m- and p-DCBs, respectively. The results demonstrated that p-DCBs were reduced more easily than o- or m-DCBs, and the order of the tendency of the dechlorination was p-DCB>m-DCB>o-DCB. The presented data show the catalytic reduction using Pd/Fe as a catalyst is a fast and easy approach for the dechlorination of DCBs. [Copyright &y& Elsevier]

Abstract: p-Dichlorobenzene (p-DCB) was dechlorinated using Pd/Fe bimetallic catalytic reductants synthesized by chemical deposition. Batch experiments demonstrated that the Pd/Fe bimetallic particles could effectively dechlorinate p-DCB, p-DCB and its intermediate chlorobenzene were removed completely at a Pd loading of 0.02% (weight ratio of Pd to Fe) and Pd/Fe power to solution ratio about 4g 75ml−1 in 90min. Dechlorination was affected by various factors such as the reaction temperature, pH, Pd loading percentage over Fe and the introduction of Pd/Fe catalysts et al. Chlorobenzene represents partially stable dechlorinated intermediates in the generation of benzene and part of p-DCB was dechlorinated to benzene indirectly on the surface of Pd/Fe. The dechlorination of p-DCB took place on the surface of the Pd/Fe bimetallic particles in a pseudo-first-order reaction, the activation energy of the dechlorination reaction was determined to be 80.0kJmol−1 at the temperature range of 287–313K. [Copyright &y& Elsevier]

Electro-coagulation was used to treat refectory wastewater with high oil and grease contents. Different operational conditions were examined, including pH, current density, reaction time, conductivity, electrode distance and inlet concentration. The optimum current density was 10–14 A m-2 within 30 min depending on the wastewater properties tested. Conductivity had little effect on the treatment efficiency. Although the addition of extra salts (e.g., sodium chloride) to the wastewater did not help increase the pollutant removal efficiency, it could save the power consumption significantly. The CODCr and oil removal efficiency descended with increasing electrode distance. The optimal electrode distance was determined to be 10 mm for this equipment in consideration of the treatment cost and efficiency together. The pH effect on the performance of the electro-coagulation process was not very significant in the range of 3–10. The removal efficiency of oil and CODCr under normal condition exceeded 95% and 75%, respectively. [Copyright &y& Elsevier]

Combining demand controlled ventilation (DCV) control and economizer control achieves acceptable and even better indoor air quality with minimum coil energy consumption. The control instability during the transition processes between different control modes are among the major difficulties faced when utilizing economizer control and when combining DCV control with economizer control in applications. A robust control strategy, using “freezing”, gain scheduling, integral term reset and feedback transition control for different transition processes, is developed for addressing these problems. They are evaluated on an air handling unit (AHU) using various simulation tests. The test results demonstrate that the robust control strategy allows stable and robust AHU control. [Copyright &y& Elsevier]

To face the climate change and carbon neutrality, reductions of energy-uses and carbon emissions are imminent. Pipe-encapsulated phase change material (PenPCM) wall is a novel envelope system with renewable energy utilizations in buildings. It combines the PCMs, nocturnal radiant cooler and gravity heat-pipe with the wall to achieve the automatic heat insulation and removal without the mechanical energy. Parameters may have influences on system performances and the parametric analysis is understudied. In this study, the influences of parameters including phase-change temperature, PCM thickness, pipe-spacings, cooler areas and orientations are investigated. The system applicability for different climate regions is also studied. Results show that, when the phase-change temperature is 27–29 °C, the ratio of the cooling load reduction to the cooling load of the conventional wall reaches largest with 17.4%. Appropriately increasing the PCM quantity can improve the thermal-storage capacity and decrease the wall temperature fluctuation. Enlarging the cooler area can increase the energy-saving effect of the PenPCM wall system. For different climate regions, the PenPCM wall system is applicable. Compared with conventional wall, the ratio of the cooling load reduction from June to September can reach 11.7%, 16.1%, 21.1%, 28.6%, 44.2% respectively for Hong Kong, Wuhan, Beijing, Harbin and Kunming. [ABSTRACT FROM AUTHOR]

Antimony contamination from textile industries has been a global environmental concern and the existing treatment technologies could not reduce Sb(V) to meet the discharge standards. To overcome this shortcoming, ferric flocs were introduced to expedite the biological process for enhanced Sb(V) removal in wastewater treatment plant (WWTP). For this purpose, a series of laboratorial-scale sequential batch reactor activated sludge processes (SBRs) were applied for Sb(V) removal with varied reactor conditions and the transformation of Fe and Sb in SBR system was investigated. Results showed a significant improvement in Sb(V) removal and the 20 mg L−1 d−1 iron ions dosage and iron loss rate was found to be only 15.2%. The influent Sb(V) concentration ranging 153–612 μg L−1 was reduced to below 50 μg L−1, and the maximum Sb(V) removal rate of the enhanced system reached about 94.3%. Furthermore, it exhibited high stability of Sb(V) removal in the face of antimonate load, Fe strike and matrix change of wastewater. Sludge total Sb determination and capacity calculation revealed decreasing in Sb adsorption capacity and desorption without fresh Fe dosage. While sludge morphology analysis demonstrated the aging and crystallization of iron hydroxides. These results verify the distinct effects of fresh iron addition and iron aging on Sb(V) removal. High-throughput gene pyrosequencing results showed that the iron addition changed microbial mechanisms and effect Fe oxidized bacterial quantity, indicating Sb(V) immobilization achieved by microbial synergistic iron oxidation. The present study successfully established a simple and efficient method for Sb(V) removal during biological treatment, and the modification of biological process by iron supplement could provide insights for real textile wastewater treatment. [Display omitted] • Ferric flocs were introduced to expedite Sb(V) removal in aerobic biological treatment system. • Moderate iron dosage into SBRs could effectively remove Sb(V), but iron aging decreased its removal rate leading to desorption. • Morphological analysis demonstrated iron hydroxides aging and crystallization. • Fresh iron supplement could effectively prevent iron aging and enhanced Sb(V) adsorption. [ABSTRACT FROM AUTHOR]

In recent years, building energy saving technologies are attracting more and more attention worldwide. A PCM-embedded wall coupled with a nocturnal sky radiator is proposed for active heat defense with the outer dynamic thermal environment. This new system can improve the building energy performance and utilization efficiency of PCM with diurnal building insulation through co-work of the PCM, nocturnal sky radiator, and active heat removal mechanism of circulating water. This paper investigates the thermal and energy performance of a typical room with the new wall system in cooling season. The system energy efficiency is analyzed by comparing with a common PCM wall and a common wall without PCM. Main influential factors on system energy efficiency are analyzed and results show that, comparing with a common wall, the average temperature of internal surface of the new system is reduced by 1.6 °C. The reduction of the cooling demand and energy-saving ratio are respectively 37.8%–57.8% and 15.7%–24.1% comparing with the reference system. Besides, the impacts of pump operation hours, area of the nocturnal sky radiator, the wall orientations and phase change temperature are discussed in depth, which can provide a useful guide for its further developments and applications. • PCM-embedded wall with nocturnal sky radiator is proposed. • New system can achieve building insulation and nocturnal active heat removal. • Thermal performance and energy efficiency are numerically analyzed. • Major influential factors on system energy efficiency are identified. [ABSTRACT FROM AUTHOR]

Self-activated phase change material (PCM) wall integrated with radiative sky cooling (RSC) is a novel wall system that uses natural energy directly for low-energy buildings to support carbon peaking and neutrality goals. A separated gravity heat pipe (SGHP) is an effective heat transfer component for heat transport from the wall body to the radiative cooler without using mechanical energy. Its heat transfer characteristics affect the thermal performance of the wall system. In this study, a numerical Volume of Fluid (VOF) model of the SGHP is established. The thermal and flow characteristics under the small temperature difference boundary of building scenarios are simulated and analyzed. Results show that the average temperature of the working fluid inside the SGHP in the "steady stage" is about 26.3 °C when the boundary temperature of the evaporation and condensation sections are respectively 28 °C and 20 °C. The heat exchange can reach 356 W/m2 and the flow velocity of the working fluid is about 0.1 m/s. Influences of different evaporation/condensation boundary temperatures on the heat transfer effect are further studied. Compared to increasing the evaporation section temperature, decreasing the condensation section temperature is a better strategy for improving the heat exchange capacity of the SGHP. • A numerical VOF model of the SGHP is established. • Thermal and flow characteristics of the SGHP are simulated. • Two parameters are proposed for estimating the heat-transfer capability of SHGP. • Thermal impacts of evaporation/condensation boundary temperatures are studied. [ABSTRACT FROM AUTHOR]

Abstract: Three-dimensional (3D) nanostructured Sn2S3 semiconductor films have been prepared on ITO-coated glass substrates by potentiostatic electrodeposition at −0.80V (vs. SCE) from a novel plating bath containing K4P2O3 as a complexing agent and Na2SO3 as a stabilizing agent and by subsequent annealing. Results showed that the annealing drove the as-deposited Sn2S3 films to grow from a granular structure into a nanorod network structure. The nanorods were around 50–100nm in diameter and 1000nm in length. The band gap of the annealed film was 1.65eV and the conductivity was n type. The carrier mobility achieved up to 20.5cm2 V−1 s−1 due to the direct electrical pathways provided by the nanorod network. [ABSTRACT FROM AUTHOR]

The energy efficiency of traditional PCM wall is low in summer since the PCM storing heat in the daytime will become a secondary heat-source and release the heat into the room again at night. In this paper, a novel pipe-encapsulated PCM wall system for self-activated heat removal is proposed. It integrates PCM, nocturnal radiation cooling and gravity heat-pipe technology, and can realize automatic heat insulation and self-activated removal for buildings. Three simplified models for pipe-encapsulated PCM are developed to predict its thermal characteristics. Model Parameters are determined and identified by using genetic algorithm. The pipe-encapsulated PCM is prepared by RT28 and expanded graphite. An experiment setup is established for model validation. Results shows that the 4R2C PCM model are preferable since the identified parameters are relatively less and the accuracy is also acceptable. Furthermore, a simple application about pipe-encapsulated PCM wall is proposed based on the coupled wall model with 4R2C PCM model. Compared with conventional wall, the internal surface accumulated heat transfer of the pipe-encapsulated PCM wall with night active heat removal in 7 days can be reduced by 74.5% in hot climate. It shows great application potential for energy-saving in buildings. [ABSTRACT FROM AUTHOR]

Indoor air humidity has a significant impact on indoor air quality, building energy consumption, and equipment performance. Excessively low or high humidity is not good for living and working. Hygroscopic materials can be used to moderate the indoor air humidity level. This paper presents a simplified dynamic moisture transfer model of building wall layer of hygroscopic material, and the parameter identification of the simplified model with genetic algorithm by comparing the frequency characteristics of the simplified model with the theoretic frequency characteristics. The proposed simplified model was validated against the published experimental measurements on the system level. The results show that the predicted moisture flux by the simplified model agrees well with the experimental test. The simplified model was also validated on room level by a common exercise in IEA 41 project. The results show that the simplified model has a good agreement with the analytical solution, within ±2.2% in the case CE1A. In the realistic case CE1B, the model prediction matches the results of these detailed models provided in public literature. The proposed simplified dynamic moisture transfer model can be used in building indoor humidity environment and energy consumption simulation with good accuracy and efficiency. • Developing a simplified dynamic moisture transfer model of building wall layer of hygroscopic material. • Model parameters are identified in the frequency domain by the basic material properties. • Validated against the published experiment measurements as well as by a published benchmark exercise. • Much more accurate than the EMPD model and more efficient than the CFD model. • Can be easily integrated into conventional simulation software, such as Simulink or TRNSYS etc. [ABSTRACT FROM AUTHOR]

Abstract Aerogel insulating panels (AIPs) exhibit extensive prospects for application in aerospace, industry and buildings as excellent energy-saving thermal insulators owing to their ultra-low thermal conductivity. This work aims to numerically and experimentally investigate the thermal performance of AIPs in building energy efficiency. The AIPs were prepared and used as an insulation layer in an insulating cell. Three insulating cells with three different insulating materials as the insulation layer were prepared to measure and comparatively analyse their thermal performances. A resistance-capacitance thermal network model to predict the thermal performance of the insulating cells was developed and validated with the experimental data. The thermal indices of cells, i.e. the time lag, decrement factor and daily heat loss, were explored under periodic disturbances of exterior air temperature. Furthermore, the thermal performance of AIPs for exterior walls was predicted by adopting the typical wall structure in the hot summer and warm winter zone of China. The results showed that the AIP wall has decreases of ∼20% and ∼40% in the fluctuation amplitude of the internal temperature and heat flow, respectively, compared with the traditional insulating walls. Highlights • A method to indicate thermal performance of AIP for energy efficiency is proposed. • Three insulating cells with EPS, GF and AIP are prepared and compared. • AIP cell shows twice time lag, 40% less decrement factor and 35% less daily heat loss. • AIP wall has ∼20% and ∼40% decreases in amplitudes of temperature and heat flow. [ABSTRACT FROM AUTHOR]

Roof is a weak part of the building envelope due to the high intensity of solar radiation in summer. Improving thermal performance of roof is crucial to reduce energy consumption. In this study, the thermal performance of a new ventilation roof with shape-stabilized phase change material (SPCM) is investigated. The dynamic heat transfer model for this roof is established by coupling the number of transfer units (NTU) heat exchange model with the resistance-capacity dynamic heat network model and used to analyse the heat transfer. The accuracy of the model is validated by experiment. The indoor air temperature, internal surface temperature of the roof, and cumulative cooling load in summer are simulated and analysed in Wuhan. The results show that PCM and night ventilation have great energy saving potential. When the 30 mm PCM is applied, the peak indoor air temperature and peak internal surface temperature decreased by 2.9 °C and 5.5 °C, respectively, and the cumulative cooling load of the building decreases by 19.2%. When night ventilation is applied (v = 3 m/s), the average latent heat utilization rate of the PCM layer increases, and the cumulative cooling load decreases by 22.9% and 37.5% compared with the PCM roof and the reference roof, respectively. [ABSTRACT FROM AUTHOR]

• A comprehensive heat transfer model of the air permeable wall was developed. • Thermal insulation mainly lies in the exfiltration process across porous layer. • Sensitivity analysis was performed to identify the impact of design parameters. • The thickness of air permeable porous layer between 30 and 50 mm was recommended. The exhaust air insulation (EAI) wall is a novel type of air permeable wall that is characterized by a permeable porous layer. Such a wall design provides a solution to combine the building envelope with exhaust air heat recovery, and allows the exhaust air from a conditioned room to permeate through. The exfiltration process of the exhaust air across the porous layer can partly reduce the inward conductive heat flux through the wall. This makes the temperature at the innermost surface of the EAI wall close to the temperature of the indoor air, and leads to the reduction of cooling and heating loads through the wall. In this study, a comprehensive heat transfer model was developed to analyze the steady state thermal characteristics of the EAI wall. Forty different experiments were performed to verify the proposed model. A quantitative analysis was conducted on the differences when using the unsteady state model and proposed steady state model for the EAI wall with an outdoor thermal disturbance. A sensitivity analysis was carried out to investigate the impact of the design parameters on the thermal characteristics of the EAI wall. The results showed that using a porous material with relatively low thermal conductivity such as phenolic foam is beneficial to improve the heat recovery performance and thermal insulation of the EAI wall. The thermal insulation of the EAI wall is mainly due to the exfiltration process of exhaust air across the porous material. Considering the impact of the design parameters on the thermal characteristic, total thickness and pressure drop, a thickness of 30–50 mm is recommended for the porous material. At an exfiltration velocity of 0.003 m/s, the U-value of the EAI wall was lower than 0.1 W/(m2 K) for a porous material thickness of 30–50 mm. These results demonstrate that the EAI wall is applicable to both energy-efficient retrofitting of existing buildings and new buildings, and can potentially contribute to reduce the cooling and heating loads through the wall by the utilization of low-grade thermal energy in exhaust air. [ABSTRACT FROM AUTHOR]

Ground heat exchanger takes the soil underground as heat source or sink to supply cooling or heating. It has been widely used in building heating and cooling systems due to high efficiency and environmental friendliness. This paper reviews the latest research on ground heat exchangers from several new perspectives and demonstrates their potentials in achieving zero energy buildings. Firstly, ground heat exchangers are classified into water-based and air-based ones based on the heat transfer medium. They can be used in a passive or active approach. Associated research and projects for each approach are introduced and analysed. Then the integration of ground heat exchangers with various cooling and heating technologies and related studies are reviewed. These technologies include solar thermal collectors, cooling towers, nocturnal radiative cooling technology, solar chimney, etc. Finally, a technical route for ground heat exchangers to help realize zero energy buildings is presented, which provides a promising solution to improve energy efficiency of buildings. [ABSTRACT FROM AUTHOR]

A hollow block ventilation wall (HBVW) is an innovative construction where the block cavity of the wall is used as a ventilation duct. Low-grade energy can be used to remove heat stored in the structure in summer and warm the structure in winter. Therefore, the cooling and heating loads of buildings can be significantly reduced. Therefore, an experimental study was conducted to investigate the thermal performance of HBVW under different airflow temperatures and rates. The temperatures and heat flux of HBVW surfaces and the airflow temperatures in cavity were tested on a typical summer day. The results show that the air velocity in the cavity has a great influence on the thermal performance. Compared with a non-ventilation wall, the thermal resistance increases from 0.637 m 2 K/W to 1.61, 3.06, 3.86, and 4.12 m 2 K/W when the air velocity is 0.3, 0.9, 1.5, and 1.9 m/s, respectively, and the heat flux transferred through the inner surface can be decreased by 40.5%, 73.3%, 79.4%, and 82.6%. The average temperature of the inner surface can be respectively decreased by 1.8, 2.8, 3.0, and 3.1 °C. The airflow temperature has little effect on the equivalent heat resistance, but it does greatly affect the inner surface temperature. [ABSTRACT FROM AUTHOR]