Improving energy saving evaluation in lighting using daylight utilization with area segregation technique

Lighting control is one of the key areas for energy saving in lighting system. Automatic control systems reduce energy consumption by decreasing load and operating time of lamps based on various factors like occupancy, time and daylight illuminance. Daylight-linked control systems can provide substantial savings in rooms with daylight availability. This approach to energy saving is called Daylight Utilization. Different methods to estimate energy savings from daylighting exist. The existing methods use simulations along with complex calculations which are suitable for research projects, but difficult to adopt for electrical designers. Moreover, some issues within these methods prevent them from estimating the maximum potential of savings. Particularly, these methods often consider the whole room as one workplane, whereas in reality the actual task area is considerably smaller. Also, the existing methods take annual average daylight penetration without considering variation of daylight penetration throughout the day or year. These problems lead to inaccurate assessment and ultimately reduced savings. This study aims to develop a new method using simulation data that considers segregation of the workplane and daylight variation for improved daylight utilization assessment. The proposed method uses two approaches to overcome the above problems of previous studies. Firstly, dividing the workplane of the room into task and surrounding area, and associating different illuminance level requirements for the two areas. Secondly, dividing the daylight penetration into three different ranges of daylight illuminance levels, thus taking into account variation in daylight illuminance. The method was applied on the simulated model of a small office room, and the annual savings potential was found to be 83.67%. The results show that the proposed method gives estimation of 73.45% savings for an office room, which is 10% higher than the results of an existing method. This shows that the new method is a viable solution for estimation of energy savings potential from daylighting

Feasibility analysis of floating photovoltaic power plant in Bangladesh: A case study in Hatirjheel Lake, Dhaka

The installation of large-scale photovoltaic (LSPV) power plants is a solution to mitigate the national energy demand in Bangladesh. However, the land crisis is one of the key challenges for the rapid growth of ground-mounted LSPV plants in Bangladesh. The per unit cost of energy from ground-mounted PV systems is rising as a response to numerous difficulties, particularly for large-scale electricity generation. To overcome the issues with land-based PV, the floating photovoltaic (FPV) could be a viable solution. To the aspirations of the Sustainable and Renewable Energy Development Authority (SREDA), this article has investigated the feasibility of constructing a floating solar plant at Hatirjheel Lake in Dhaka, Bangladesh. The lake is an excellent spot to build an FPV plant due to its geographic location and climatic conditions inside the capital city. In this paper, the design of the plant and tariff are carried out using the PVsyst simulator. It is found that the optimum cost of energy for the plant is $ 0.0959/KWh, which is lesser than the currently operational ground-mounted PV plants in Bangladesh. Additionally, the projected 6.7 MW plant can meet 12.5 % of the local energy demand. Furthermore, the FPV plant is capable to cut off 6685 tons of CO2 annually. A reduction in power costs and environmental protection would assist the government of Bangladesh in achieving the sustainable development goals and electricity generation target of 6000 MW from solar photovoltaics by 2041 as well

The Effects of Non-Uniformly-Aged Photovoltaic Array on Mismatch Power Loss: A Practical Investigation towards Novel Hybrid Array Configurations

One of the most important causes of a reduction in power generation in PV panels is the non-uniform aging of photovoltaic (PV) modules. The increase in the current–voltage (I–V) mismatch among the array modules is the primary cause of this kind of degradation. There have been several array configurations investigated over the years to reduce mismatch power loss (MPL) caused by shadowing, but there have not been any experimental studies that have specifically examined the impact of various hybrid array topologies taking PV module aging into consideration. This research examines the influence of the non-uniform aging scenario on the performance of solar PV modules with various interconnection strategies. Experiments have been carried out on a 4 × 10, 400 W array with 12 possible configurations, including three proposed configurations (LD-TCT, SP-LD, and LD-SP), to detect the electrical characteristics of a PV system. Finally, the performances of different module configurations are analyzed where the newly proposed configurations (SP-LD and LD-SP) show 15.80% and 15.94% higher recoverable energy (RE), respectively, than the most-adopted configuration (SP). Moreover, among the twelve configurations, the SP configuration shows the highest percentage of MPL, which is about 17.96%, whereas LD-SP shows the lowest MPL at about 4.88%

The effects of non-uniformly-aged photovoltaic array on mismatch power loss : A practical investigation towards novel hybrid array configurations

One of the most important causes of a reduction in power generation in PV panels is the non-uniform aging of photovoltaic (PV) modules. The increase in the current–voltage (I–V) mismatch among the array modules is the primary cause of this kind of degradation. There have been several array configurations investigated over the years to reduce mismatch power loss (MPL) caused by shadowing, but there have not been any experimental studies that have specifically examined the impact of various hybrid array topologies taking PV module aging into consideration. This research examines the influence of the non-uniform aging scenario on the performance of solar PV modules with various interconnection strategies. Experiments have been carried out on a 4 × 10, 400 W array with 12 possible configurations, including three proposed configurations (LD-TCT, SP-LD, and LD-SP), to detect the electrical characteristics of a PV system. Finally, the performances of different module configurations are analyzed where the newly proposed configurations (SP-LD and LD-SP) show 15.80% and 15.94% higher recoverable energy (RE), respectively, than the most-adopted configuration (SP). Moreover, among the twelve configurations, the SP configuration shows the highest percentage of MPL, which is about 17.96%, whereas LD-SP shows the lowest MPL at about 4.88%

Enhanced Energy Savings in Indoor Environments with Effective Daylight Utilization and Area Segregation

Daylight utilization is one of the key areas for energy savings in indoor environments. An important factor often not considered by the existing daylight utilization approaches is the segregation of the floor into task areas and non-task areas. It is also observed that the inherent asymmetry in the daylight penetration pattern in most indoor environments is not given consideration while designing artificial lighting arrangements. Moreover, daily and annual daylight availability is found to have a symmetrical variation pattern, which is a significant factor often overlooked in utilizing daylight. Thus, the energy assessment can be inaccurate, leading to an incorrect or impractical evaluation of energy savings. This research proposes a comprehensive new approach to assess the energy-saving potential of daylight utilization in indoor environments. This new method combines two approaches to overcome the aforementioned issues. (1) The considered area is segmented into task area and non-task areas (or surrounding area) and considers different levels of required illuminance for each separate area. (2) The variation of available daylight at the considered location is accounted for by dividing the daylight penetration into multiple levels. For the study, the method is first applied to a simulated office space considering real-life parameters, where the annual energy savings were estimated at 83.67%. For further validation, a comparison with a case from an existing method was also carried out, and the proposed method gave an energy saving estimation of 73.45%. This indicates a 10% higher energy saving estimation as compared to the original study, against which the proposed method was compared

Energy saving in lighting from T5 lamp retrofits - a case study

Energy Efficiency is one of the main focuses of research in Electrical Engineering at the present time. Lighting system carries a considerable amount of the total electricity usage in buildings. Hence researchers have been continuously thriving to achieve better efficiency in lighting, which means maintaining optimum lighting conditions using as less energy as possible. Using energy efficient lamps with higher luminous efficacy (lumen/watt) is an effective way to reduce the lighting load while maintaining optimum light levels, thus making the lighting system more efficient. Universiti Teknologi Malaysia (UTM) undertook a large scale project to replace the university's existing installations of T8 lamps with more efficient T5 lamps. This paper presents an overview of the project, its scale, the estimated and actual savings from the project, and looks toward further studies in the future

Self correction fractional least mean square algorithm for application in digital beamforming.

Fractional order algorithms demonstrate superior efficacy in signal processing while retaining the same level of implementation simplicity as traditional algorithms. The self-adjusting dual-stage fractional order least mean square algorithm, denoted as LFLMS, is developed to expedite convergence, improve precision, and incurring only a slight increase in computational complexity. The initial segment employs the least mean square (LMS), succeeded by the fractional LMS (FLMS) approach in the subsequent stage. The latter multiplies the LMS output, with a replica of the steering vector (Ŕ) of the intended signal. Mathematical convergence analysis and the mathematical derivation of the proposed approach are provided. Its weight adjustment integrates the conventional integer ordered gradient with a fractional-ordered. Its effectiveness is gauged through the minimization of mean square error (MSE), and thorough comparisons with alternative methods are conducted across various parameters in simulations. Simulation results underscore the superior performance of LFLMS. Notably, the convergence rate of LFLMS surpasses that of LMS by 59%, accompanied by a 49% improvement in MSE relative to LMS. So it is concluded that the LFLMS approach is a suitable choice for next generation wireless networks, including Internet of Things, 6G, radars and satellite communication

Determining the most sensitive socioeconomic parameters for quantitative risk assessment

Risk is assessed as a function of exposure, hazard, and vulnerability, defined in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5), where exposure and vulnerability are described through socioeconomic indicators. Indicators are selected through sensitivity analysis performed by applying a non-linear programming system, which is solved by Karush-Kuhn-Tucker conditions. In this article, the Kolmogorov-Smirnov statistical test is applied to select the set of indicators that are the most sensitive for the system to assess risk, and then applied to the case of the Bangladesh coast to determine the most sensitive socioeconomic indicators.UK Government’s Department for International Development (DFID

Usefulness of intraoperative computed tomography on extent of resection of large and giant pituitary adenomas. Experience from a developing country

Background and Objective: The literature on the use of intraoperative computed tomography (iCT) is sparse. We provide our experience of the usefulness of iCT in extent of resection in large and giant pituitary adenomas. Methods: A retrospective review was performed of cases using the endonasal endoscopic technique in which iCT was used. Demographic factors, number of scans, and impact on the extent of resection are reported, with visual acuity and field changes. Tumors were graded according to the Hardy classification. Patients with cavernous sinus invasion were excluded. Results: All patients received a perioperative computed tomography scan with our iCT scanner. Thirty patients are reported, including 14 large and 16 giant pituitary adenomas, including 14 nonfunctional and 16 growth hormone–secreting tumors. The overall gross total resection (GTR), near-total resection, and subtotal resection rates were 83.3%, 16.7%, and 3.3%, respectively. iCT scanning detected residual in 13 of 30 patients, including 4 with 14 large (29%) and 9 with 16 (56.3%) giant adenomas promoting further surgery. iCT use improved GTR from 43.8% to 81.3% in giant adenomas and from 71% to 86% in large adenomas. Of the 13 patients in whom iCT detected residual disease, none required >2 iCT scans. No intraoperative complications were observed. Conclusions: iCT can improve extent of resection in large and giant pituitary adenomas and facilitate maximum safe resection such as GTR or near-total resection in patients where such should be attempted. iCT use may reduce iatrogenic complications and has select financial benefits in our patients' socioeconomic demographics. However, further prospective controlled studies are required to affirm our conclusions