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"Ramirez-Iniguez, Roberto"
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LED-based indoor positioning system using novel optical pixelation technique
At present, about 47 million people worldwide have Alzheimer's disease (AD), and because there is no treatment currently available to cure AD, people with AD (PWAD) are cared for. The estimated cost of care for PWAD in 2016 alone is about $236 billion, which puts a huge burden on relatives of PWAD. This work aims to reduce this burden by proposing an inexpensive indoor positioning system that can be used to monitor PWAD. For the positioning, freeform lenses are used to enable a novel optically pixeled LED luminaire (OPLL) that focuses beams from LEDs to various parts of a room, thereby creating uniquely identifiable regions which are used to improve positioning accuracy. Monte Carlo simulation with the designed OPLL in a room with dimensions $5\\, {\\rm m} \\times 5\\, {\\rm m} \\times 3\\, {\\rm m}$5m×5m×3m is used to compute the positioning error and theoretical analysis and experiments are used to validate the time for positioning. Results show that by appropriate LED beam design, OPLL has a positioning error and time for positioning of 0.735 m and 187 ms which is 55.1% lower and 1.2 times faster than existing multiple LED estimation model proximity systems.
Journal Article
Use of a 2-layer thermoelectric generator structure for photovoltaics cells cooling and energy recovery
A 2-layer thermoelectric generator was tested as a solution to increase the output of a PV cell. A number of practical experiments were carried out on both single and two combined thermoelectric generator (TEG) configurations connected in series with photovoltaic (PV) cells and connected to a load independently from each other. Testing was performed using a class AAA solar simulator system Sol3A and under real outdoor weather conditions. The results show a reduction of the maximum cell temperature by 10.3 ° on average and at the same time an increase in the tested photovoltaics-thermo-generators (PV-TEGs) voltage output of the proposed hybrid systems by 28.56-30.54% compared to the plain PV cell. It was experimentally confirmed that the TEGs-PV structure performs better than the bare PV cell during decline of insolation utilising, in addition to the limited at this time solar energy, the heat accumulated by the multilayer structure components. Experiments showed that for the selected period of time (1600s) the energy output increased by 27.6% compared to a plain PV cell. For a constant level of artifical light (1000W/m 2 ) the PV-TEG’s hybrid system showed an increase of energy yield of 3.1% compared to a plain PV system.
Journal Article
Optical Boundaries for LED-Based Indoor Positioning System
Overlap of footprints of light emitting diodes (LEDs) increases the positioning accuracy of wearable LED indoor positioning systems (IPS) but such an approach assumes that the footprint boundaries are defined. In this work, we develop a mathematical model for defining the footprint boundaries of an LED in terms of a threshold angle instead of the conventional half or full angle. To show the effect of the threshold angle, we compare how overlaps and receiver tilts affect the performance of an LED-based IPS when the optical boundary is defined at the threshold angle and at the full angle. Using experimental measurements, simulations, and theoretical analysis, the effect of the defined threshold angle is estimated. The results show that the positional time when using the newly defined threshold angle is 12 times shorter than the time when the full angle is used. When the effect of tilt is considered, the threshold angle time is 22 times shorter than the full angle positioning time. Regarding accuracy, it is shown in this work that a positioning error as low as 230 mm can be obtained. Consequently, while the IPS gives a very low positioning error, a defined threshold angle reduces delays in an overlap-based LED IPS.
Journal Article
Assessment of the RACPC Performance under Diffuse Radiation for Use in BIPV System
In the last four decades there has been a significant increase in solar photovoltaic (PV) capacity, which makes solar one of the most promising renewable energy sources. Following this trend, solar power would become the world’s largest source of electricity by 2050. Building Integrated Photovoltaic (BIPV) systems, in which conventional materials can be replaced with PV panels that become an integral part of the building, can be enhanced with concentrating photovoltaic (CPV) systems. In order to increase the cost efficiency of a BIPV system, an optical concentrator can be used to replace expensive PV material with a lower cost option, whilst increasing the electrical output through the concentration of solar power. A concentrator called rotationally asymmetrical compound parabolic concentrator (RACPC) was analysed in this work under diffuse light conditions. Software simulations and experimental work were carried out to determine the optical concentration gain of the concentrator. Results from this work show that, under diffuse light, the RACPC has an optical concentration gain of 2.12. The experimental work showed a value of 2.20, which confirms the results with only a 3.8% difference.
Journal Article
Annual Prediction Output of an RADTIRC-PV Module
The number of solar photovoltaic (PV) installations has been increasing worldwide but the high capital cost of installation continues to be the main challenge, particularly in many developing countries. The solar concentrator, a device that focuses the sunlight onto a small area, has the potential to minimize the use of expensive PV material while maintaining the system’s performance, ultimately bringing down its overall cost. This study aims to predict the annual electrical output of a specific concentrator design called the rotationally asymmetrical dielectric totally internally reflecting concentrator (RADTIRC). The aforementioned design is assumed to be installed in Berlin/Brandenburg, Germany. First, a short review of concentrators is provided. Next, a description of the RADTIRC and the previous research that revolved around it are provided. Afterwards, the key parameters that are needed to determine the annual electrical output of the RADTIRC are explained before presenting the results of the simulations. It was found that the yearly energy yield was increased by a factor of 2.29 when the RADTIRC-PV module was used when compared with the non-concentrating PV module.
Journal Article
Embodied Energy and Cost Assessments of a Concentrating Photovoltaic Module
This paper focuses on the embodied energy and cost assessments of a static concentrating photovoltaic (CPV) module in comparison to the flat photovoltaic (PV) module. The CPV module employs a specific concentrator design from the Genetically Optimised Circular Rotational Square Hyperboloid (GOCRSH) concentrators, labelled as GOCRSH_A. Firstly, it discussed previous research on life cycle analyses for PV and CPV modules. Next, it compared the energy embodied in the materials of the GOCRSH_A module to the energy embodied in the materials of a flat PV module of the same electrical output. Lastly, a comparison in terms of cost is presented between the analysed GOCRSH_A module and the flat PV module. It was found that the GOCRSH_A module showed a reduction in embodied energy of 17% which indicates a reduction in embodied carbon. In terms of cost, the costs for the GOCRSH_A module were calculated to be 1.71 times higher than the flat PV module of the same electrical output. It is concluded that a trade-off is required between the embodied energy and cost impacts in order to bring this CPV technology into the market.
Journal Article
Potential of Implementing the Low Concentration Photovoltaic Systems in the United Kingdom
This paper discusses the prospect of integrating a novel type of low concentration photovoltaic (LCPV) design known as the rotationally asymmetrical compound parabolic concentrator (RACPC) in a building in the United Kingdom. This is done by proposing a number of building integration designs to create a zero carbon building. A cost reduction analysis of installing the LCPV systems in the country is also presented. It was found that an RACPC design could reduce the LCPV module’s manufacturing cost by 31.75% and the LCPV module’s cost per unit power output by 33.87% when compared with the conventional PV module.
Journal Article