The scope of this paper is to review different types of sustainable water harvesting methods from the atmospheric fogs and dew. In this paper, we report upon the water collection performance of various fog collectors around the world. We also review technical aspects of fog collector feasibility studies and the efficiency improvements. Modern fog harvesting innovations are often bioinspired technology. Fog harvesting technology is obviously limited by global fog occurrence. In contrast, dew water harvester is available everywhere but requires a cooled condensing surface. In this review, the dew water collection systems is divided into three categories: i) dew water harvesting using radiative cooling surface, ii) solar-regenerated desiccant system and iii) active condensation technology. The key target in all these approaches is the development of an atmospheric water collector that can produce water regardless of the humidity level, geographical location, low in cost and can be made using local materials.

Windows are one of the significant indicators of the energy efficiency of a building and have undergone extensive research since the last decades. This paper reviews the performance of various window technologies covering the physical and optical properties of traditional windows and advanced window technologies. In window technologies, one of the most critical parameters is its thermal transmittance value or also known as U-value. In this paper, we discuss the relationship between the physical and optical parameters of the different types of windows and its U-value. Additionally, this paper will also provide interested readers with a wide range of information, including the research gaps in window technologies. Among the main conclusions, we found that, although several advancements have been achieved in this field in the last decade, further research is needed to develop window technologies that not only have high insulating properties but also can generate power.

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a b s t r a c tThis paper discusses theoretical and indoor experimental studies of a bi-fluid type photovoltaic/thermal PV/T solar collector. 2D steady-state analysis was developed and computer simulation was performed using MATLAB. Experiments were conducted for steady-state analysis under the solar simulator at Solar Energy Research Lab UiTM Perlis, Malaysia. The test includes all three modes of fluid operation under the same PV/T system, namely: the air mode, the water mode, and the simultaneous mode of water and air. The simulation results were validated against the experimental results using three methods of error analysis: root mean square percentage deviation (RMSPD), mean absolute percentage error (MAPE), and coefficient of determination (R 2 ). On average, the MAPE, RMSPD, and R 2 computed for the fluid output temperature are approximately 0.92%, 1.19%, and 0.98, respectively. Thus, we concluded that the simulation and experimental results are in good agreement. The PV/T collector designed in this study has a variety of applications as it can be operated in three different modes of fluid operation, and the theoretical model is useful in modelling all three modes without further modification.