Shahzada Pamir Aly

Novel dry cleaning machine for photovoltaic and solar panels

Accumulation of dust (also known as soiling) on the surface of solar panels decreases the amount of sunlight reaching the solar cells underneath and thus the efficiency of the solar panel is severely impacted. To harness their designed capacity to its fullest, they need to be cleaned periodically, usually with water. The Middle East region is a very suitable region for harvesting solar energy due to abundance of sunlight, but there is also a profusion of sand and dust. Due to water scarcity in this area, cleaning becomes difficult, challenging and subsequently costly. Here, a novel four-stage automated `dry cleaning method is reported for solar panels. The proposed cleaning process is carried out in four stages with no involvement of liquids. The cleaning process involves compressed air spray, followed by cleaning through a foam roller and a polywool synthetic duster. An electronically controlled mechanical assembly holds the rollers and guides them along the solar panels. A set of servo motors and a stepper motor is installed on the assembly to rotate and guide the cleaning structure. The system is very useful for small and large installations alike, especially in dry areas where there is little or no rain throughout the year.

Full space device optimization for solar cells

Advances in computational materials have paved a way to design efficient solar cells by identifying the optimal properties of the device layers. Conventionally, the device optimization has been governed by single or double descriptors for an individual layer; mostly the absorbing layer. However, the performance of the device depends collectively on all the properties of the material and the geometry of each layer in the cell. To address this issue of multi-property optimization and to avoid the paradigm of reoccurring materials in the solar cell field, a full space material-independent optimization approach is developed and presented in this paper. The method is employed to obtain an optimized material data set for maximum efficiency and for targeted functionality for each layer. To ensure the robustness of the method, two cases are studied; namely perovskite solar cells device optimization and cadmium-free CIGS solar cell. The implementation determines the desirable optoelectronic properties of transport mediums and contacts that can maximize the efficiency for both cases. The resulted data sets of material properties can be matched with those in materials databases or by further microscopic material design. Moreover, the presented multi-property optimization framework can be extended to design any solid-state device.

A fully transient novel thermal model for in-field photovoltaic modules using developed explicit and implicit finite difference schemes

Abstract Three fully transient numerical thermal models have been developed for photovoltaic (PV) modules in MATLAB environment, using 2-D finite difference (FD) method. One of the thermal FD model is based on explicit time scheme, while the other two are based on implicit time schemes. Out of the two implicit FD models, one has been modeled using preexisting toolboxes of MATLAB, while the other has been modeled using a self-developed novel method. All the three FD models are based on energy balance of different control volumes, which as a whole constitute the complete solid domain of the PV panel. The models have been tested against a variety of experimental data, ranging from sunny clear days, sunny cloudy days, rainy overcast days and consecutive sunny clear days. All the three models are found to agree very well with experimental results, i.e. the errors between the modeled and experimental data ranges between 0.2–0.7u202f°C. The main difference is between their computational speeds. In terms of average execution time per iteration for transient analyses, the self-developed novel implicit method (referred to as implicit BB throughout the work) was about 1200 times slower than the explicit method. However, overall, the implicit BB method took less time for the entire transient analyses, as it requires less number of iterations due to its tolerance to adapt longer time steps for each iteration. In other words, the explicit method although slightly more accurate, took approximately 900 times more CPU time to simulate the same time span test compared to implicit BB method. Thus, the self-developed novel method (implicit BB) has been recommended for these types of thermal models.

Thermal Behavior of Aluminum Alloy Metal Foam Heat Sinks: A Computational and Experimental Approach

Metal foams are structures of a cellular nature that contain a high percentage of porosity that can be produced in either a closed or open cell forms. The use of metal foams in engineering applications has increased significantly over the last decade due to their enhanced mechanical and thermal properties. An innovative approach for three-dimensional (3D) detailed finite element modeling of open cell metal foam has been taken to capture the versatile nature of metal foams’ geometry and predicting its thermal performance. The interior complex geometry of metal foams has limited studies to create computational model via common approaches. Therefore, not much computational work has been done in open cell metal foam applications. To overcome this difficulty, computed tomography (CT) scan has been used to extract the 3D structure surface model with extreme precision. Computer-Aided Design (CAD) software has been used for “stitching” and “healing” of the CT scan model before importing it to a finite element domain. The 3D computational model is used in a heat sink application and is calibrated against experimental results for the temperature distribution of one case. The validated and calibrated model is then used for simulating different metal foam heat sink cases to assess the thermal and mechanical behavior under different conditions.Copyright

Mitigating the effect of heat and dust to enhance solar panels efficiency

Solar panels are used to directly convert sunlight into electric current. Associated with a useful range of the solar spectrum is the rest unwanted irradiation, causing the temperature rise in the solar cells, which ultimately reduces the efficiency and power output of most of panels. Furthermore, dust settlement on the surface of panel, also referred to soiling, is another factor that reduces the efficiency, at least by shading. A novel, simple, cheap and robust system has been proposed in this study to mitigate the notorious effects of heat, as well as dust, through the use of forced air draft produced via a fan. The findings highlight that a cumulative power gain of at least 48.4 W under tested conditions can be achieved by implementing this system, on an array of solar panels constituting eight modules. Whereas, including the effect of natural wind in the analyses, further increases the power gain. The results obtained have been validated by the use of 3D finite element modeling, as well as through literature.