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Abstract St. George's School, Wallasey, latitude 53°25′N, is heated by solar radiation and heat from the lighting and the occupants; no conventional heating is used. General reasoning suggests that it should be advantageous to use solar heat in this locality in winter. Constructional features associated with the solar design are discussed. The results of an observational study suggest that temperatures of 16°C and above can be achieved in winter; daily mean air temperatures of up to 24.5°C are found in summer, with higher peak values. Serious overheating has occurred but is rare. The heating costs appear to be low compared with some other secondary schools. User study findings are reported. While shortcomings in the Wallasey realisation are noted, it is concluded that the principle of using solar gain to heat buildings is practicable and economic.

A recent innovation in evacuated tubular solar collector technology is described. A desorbable gas, which specifically adsorbs on the graphitic solar selective surface, can reversibly degrade the vacuum by providing a heat conduction path at elevated temperatures. The stagnation temperature of the system is thus limited in a controllable manner without significantly degrading the low temperature performance. A simple theory incorporating the Langmuir adsorption isotherm and the Knudsen free molecule transport regime is used to describe the phenomenon.

Abstract Luminescent CdTe nanoparticles were synthesized in aqueous medium at low temperature under the inert atmosphere using water soluble precursors. Potassium tellurite was employed as the tellurium source for the synthesis. As synthesized CdTe nanoparticles were phase transferred into organic medium via partial ligand exchange method through long chain organic ligand 1-dodecanethiol in the presence of acetone. The phase transferred CdTe nanoparticles were blended homogeneously with P3HT polymer in a common solvent (chloroform) for possible application as the active layer in hybrid solar cell structure. The prepared blends were characterised with UV–Vis, Photoluminescence, SEM and AFM analysis. The XRD patterns of the particles in two phases confirm the uniformity of the cubic structure. The size distribution of the synthesized particles was confirmed through TEM analysis. The effective interactions of the donor and acceptor components were confirmed through UV–Visible spectroscopy. The efficient charge transfer processes of the blends were confirmed through photoluminescence analysis of the nanoparticles various volume additions with polymer. The morphological analysis of the blends was carried out using the Scanning Electron Microscopy which reveals the distribution of the nanoparticles in the polymer. AFM analysis of the coated blend film explores the phase separation of the nanoparticles when blended with the polymer in chloroform. Advantages of these nanoparticles for solar cell applications were discussed.

Abstract Kesterite Cu2ZnSnS4 (CZTS) solar cells are regarded as a promising photovoltaic technology owing to the non-toxic and earth-abundant constitutes. With the application of scalable and low-cost solution methods, the possibility of its commercialization can be further increased. This work explores preparing prominent CZTS films by an economically feasible successive ionic adsorption and reaction (SILAR) synthesis method. The obtained precursor with the Mo/ZnS/Cu2SnS3 structure requires appropriate substantial annealing under a chalcogen atmosphere to form kesterite CZTS films. The annealing process is therefore optimized to improve the film quality and the performance of solar cells. Specifically, the optimal annealing condition is determined by adjusting the annealing temperature and holding time, respectively. The CZTS film annealed at 580 °C for 60 min demonstrates better film quality in terms of surface morphology, crystallinity, and phase purity. Consequently, CZTS solar cells fabricated with the optimal absorber exhibit a preferable efficiency of up to 4.26%.

Abstract Buildings often have fixed function spaces that are complimentary or incompatible with thermal comfort (18–28 °C). Synergetic relationships ameliorates energy shortage and affords comfort. Galvanized iron roof two-storey houses of North-East India were studied to develop a theory-and-strategy to optimize design process and energy conservation. Methods include affordance theory criticism, surveys, simulations, synergy analysis. Parametric strategy on passive design affordances examines human comfort and temperature on diurnal time scales: Daytime (08–17 h), Evening (17–22 h), Night (22–08 h) in various seasons. Under flexible ventilation, living-dining space (S1) shows optimum temperature ranges: 20–28 °C in autumn (M1), 17–22 °C in winter (M2), and 20–31 °C in summer (M3) due to the complementary combination of passive design elements and can function as bedroom, living-room, kitchen, and social space in most seasons. In the attic-space flexible ventilation shows peak temperatures of 42 °C (autumn) and 48 °C (summer) due to low thermal mass but high thermal conductivity envelopes, and low air-changes rate (0.5 ACR) above 28 °C. Normal ventilations with 30 ACR in autumn, and a combination of 30 ACR (night) and 0.5 ACR (day) in summer reduced maximum temperature to ≤35 °C in autumn, and ≤41 °C in summer. Attic-space (S2) shows ≤29 °C in winter daytime and ≥20 °C in summer nights due to the envelope’s high heat emissivity (0.8) and function as day space in winter and summer bedroom. Shaded veranda (S3) shows low temperature (18–28 °C) in summer evening and afternoon and can function as shaded space for light work and enjoying fresh air. Passive design connotes responsiveness of spaces to the climate, and affordance theory’s complementarity lifestyle adds novelty, and it is critical to energy and space efficiency. Climate analysis affords perceptions of space and climate relationship. Parametric strategy straddles differences between space, climate, and functions to ameliorate energy needs and optimize design process.

Abstract Thin film solar cells with ITO/ZnO/P3HT:PCM:CTSe NCs/Ag structure were fabricated employing a fast and cost-effective procedure using blended solution of P3HT:PCBM:CTSe NCs deposited by spin casting, followed by thermal annealing steps. The CTSe NCs are prepared via solvothermal method. An inverted architecture of device with structure ITO/ZnO/P3HT: PCBM:CTSe NCs/Ag have been fabricated with different concentration of CTSe NCs in poly(3-hexyle thiophene) (P3HT): [6,6]phenyl-C61-butyric-acid-methyl-ester (PCBM) matrix. The effect of CTSe NCs on the performance of hybrid solar cell with optimized blend ratio of P3HT:PCBM and CTSe NCs has been investigated for optimum power conversion. The charge carrier extraction and recombination at the interface of donor-acceptor material were studied using Electrochemical impedance spectroscopy (EIS) under dark condition. EIS study has demonstrated that the charge transfer rate was higher for the device having optimized wt% of CTSe NCs (10 wt%) in P3HT:PCBM active layer. A significant improvement in the device performances was observed on incorporation of CTSe NCs. The device exhibited open circuit voltage (Voc) of 0.475 V, short circuit current density (Jsc) of 6.95 mA/cm2, fill factor (FF) of 0.41 and power conversion efficiency (PCE) of 1.35%.

The behaviour of lead-acid batteries during dynamic operation on a long-period basis is analyzed in this paper. An algorithm which takes into account all possible battery conditions during real operation has been developed and is used for the battery state of voltage, SOV, predictions. This battery algorithm is general and therefore can be used for other types of accumulators, provided that the model parameters are known. For model validation, a typical battery was incorporated for energy storage in a stand-alone, renewable power supply system and the experimental results were compared with the algorithm predictions. The results show that very good agreement between measured and simulated battery SOVs has been achieved for monthly periods of continuous system operation.

Abstract With an aim to prepare phase change material (PCM) as self-sustaining film from poly(ethylene glycol) (PEG) having reduced hydrophilicity, cross-linking of PEG and hydroxy-terminated poly(dimethyl siloxane) (HTPDMS) was done by using tetraethyl orthosilicate (TEOS) as a cross-linking agent. Following the confirmation of the crosslinked polymer using FTIR and 13C-solid state NMR, the crystallization properties were studied using X-ray diffraction and polarized optical microscopy. DSC analysis indicated an increase in enthalpy with increasing concentration of PEG. The enthalpy of fusion and crystallization was observed to reach a maximum of 125 and 104 J g−1 respectively. Contact angle of 89.5° has been achieved for polymer with highest concentration of HTPDMS. The material with lowest PEG concentration was film forming in nature. This material can be extensively used as a thermal energy storage material particularly, in smart packaging.