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Abstract The four different techniques which were used to test an advanced, four-pane glazing system and standard double-glazed unit are described. The results from each test are compared. Where agreement is not good, explanations are suggested. The advanced glazing system was found to have a U -value of 0.9 W/m 2 K and a shading coefficient of 0.48. The glazing simulation models WINDOW (Lawrence Berkeley Laboratories, Berkeley, CA, U.S.) and MULTB (Pilkington Glass, U.K.) were used to predict glazing performance. Simulation of the two glazing systems which were experimentally assessed allows comparison between models, and between predicted and measured performance. Agreement was within the error bands associated with each assessment.

Abstract An analysis is made of the steady state temperatures reached by bodies exposed to sunlight. The effects of corrugations or concavities are discussed for different over-all configurations; also the effects of blackness, grayness, and color. Numerical results are given for several significant cases, applicable to space vehicles and to solar collectors.

The high capital costs associated with heat-pipe evacuated tube solar water heating systems can be reduced by replacing forced circulation with thermosyphon circulation. Currently research on thermosyphon heat-pipe evacuated tube solar water heaters is limited. An experimental investigation of the natural convective heat exchange regime that exists within the manifold chamber of a proprietary heat-pipe evacuated tube solar water was undertaken. This paper presents experimental data from a heat-pipe Evacuated Tube Solar Water Heater (ETSWH) subjected to the Northern Maritime Climate at the University of Ulster’s outdoor solar testing facility located at the Jordanstown campus. The thermal performance of this across solar noon (±30 min) was experimentally determined to be comparable to two physical laboratory 10 pin-fin model manifolds constructed to the same dimensions and geometry as the manifold chamber of the heat-pipe ETSWH when operated under steady laboratory conditions. When the surface temperatures of the pin-fins (simulated condensers) in the model manifold were normalised with respect to the lowest most pin-fin in the array the influence of buoyant flow was observed. Similarly to related studies in this field it was found that normalised surface temperatures on downstream pin-fins do not increase monotonically as would be expected if no interactions occur. It was found that at the pin-fin diameter to pitch used in the model manifold that normalised surface temperatures decrease at certain points in the array due to the action of buoyant flow generated from upstream pin-fins which increased heat transfer. Two-dimensional Particle Imaging Velocimetry (2D-PIV) was used to visualise the thermosyphon fluid flow regime. It was observed that the fluid flow regime varied across the model due to interactions between the fluid, chamber walls and pin-fins.

Abstract The interfaces between n-type silicon (n-Si) and metal electrode contact have enormous influences on the performance and stability of silicon solar cells. Recently, it has been proven that the carrier-selective contact (CSC) is an effective strategy to improve the device efficiency. Herein, a solution-processed and annealing-free zirconium acetylacetonate (ZrAcac) layer is used as an electron-selective contact for fabricating efficient crystalline silicon solar cell. This contact scheme enabled a reduction in both the contact resistivity and the work function at the interface between n-Si and Al, which can be attributed to the dipole formation at the contact interface induced by charge transfer. The application of this ZrAcac based contact was shown to consistently improve all device parameters reaching a maximum power conversion efficiency of 17.8% with a high fill factor of 81.1%, and greatly improve the device stability. This work demonstrated that the ZrAcac layer can provide sufficient energy alignment and enhanced carrier selectivity for efficient and stable photovoltaic devices.

Abstract Photovoltaic (PV) modules convert part of incident solar energy into electrical energy for commercial applications, with the rest being transferred to heat energy. The modelling of PV modules plays an important role in the fault diagnosis of a PV array. The object of this paper is to develop a parameter based model of a PV module. This model is sequentially coupled with an electrical model and energy balance equation. In order to establish the parameter based model, key parameters including the total effective solar energy, total heat exchange coefficient and ambient temperature are calculated from two working points on PV module along with the corresponding temperature from a thermal camera. Using the developed model, a fault diagnosis method based on the model is illustrated. Finally, model validation is carried out by the experiments.

It has been found in many countries with arid climates that massively walled buildings provide steady, comfortable inside temperatures even though the outside temperature fluctuations may be sizeable. The adobe houses of the American South-West, and the rondavels of southern Africa are particular examples. This phenomena is often termed the thermal flywheel effect. One explanation is that the temperature at the inside of a massive wall lags approximately out of phase with the outside, and so it partly offsets the direct, in phase, infiltration losses into the building. Thus the room temperature is kept approximately constant. In this paper the question of designing a non-homogeneous wall to optimize this effect is considered.

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.

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 This paper proposes a generalized analytical approach to model the photovoltaic (PV) arrays under partial shading conditions (PSC). The proposed method is simple: it requires only the standard test condition (STC) parameters of the PV modules and the irradiance level imposed on each module. By using this information, the P-V and I-V curves of shaded PV arrays are obtained by simple steps. Firstly, the current-voltage (I-V) curves for all assembled submodules receiving the same level of irradiance are generated using the two-diode model. The parameters of the latter are computed using a fast parameter extraction method. Secondly, the I-V curve of each shaded string is computed using the computed I-V curves of its submodules. In the last step, the resulted I-V curve of the array is obtained by summation of all I-V strings curves. The proposed method is simple, fast, and can be coded in any development platform. Besides, the prediction accuracy is enhanced by incorporating the real effect of bypass and blocking diodes in the model. Furthermore, the proposed method could be generalized for any number of series/parallel connections in a shaded PV array. The method can be useful to generate critical shading patterns for maximum power point tracking (MPPT) algorithms evaluation. It can also be used as a tool to obtain instant shading patterns in PV array simulators.