Volume 3 Issue 4
Authors: Prasanta kumar Pany; Sakti Prasad Ghoshal
Abstract: Price forecasting has become an important activity for market participants in electric power industry for developing their bidding strategies. The work presented in this paper makes use of particle swarm optimization based local linear wavelet neural networks (LLWNN) to find the Market Clearing Price (MCP) for a given period, with a certain confidence level. The results of the new method show significant improvement in the price forecasting process.
Keywords: Electricity Price, Forecasting, Wavelet Neural Network (WNN), Local Linear Wavelet Neural Network (LLWNN), Particle Swarm Optimization (PSO), Market Clearing Price (MCP), Weekly Mean Absolute Percentage Error (WMAPE)
Authors: Maatouk Khoukhi
Abstract: Indoor moist surroundings affect air cleanliness and thermal comfort when relative humidity is above 70%, which may lead to condensation within the building structure and on interior and exterior surfaces and subsequent development mould and fungi. Moreover, the humidity issue is a major contributor to energy inefficiency in HVAC devices. The objective of this study was to investigate the feasibility to apply the desiccant cooling system in hot-humid climate for interior thermal comfort purpose. Using measured data sets, validation of TRNSYS basic model was undertaken. Two models of cooling system using Indirect Evaporative Cooling (IEC) and Direct Evaporative Cooling (DEC) were simulated for different climatic conditions. The result shows that the desiccant cooling system with IEC and DEC can be a suitable solution for thermal comfort in buildings in hot-humid climate.
Keywords: Desiccant Cooling; Desiccant Wheel; Heat Wheel, Dry-bulb Temperature; Relative Humidity; Evaporative Cooler
Authors: Mokalla. Srinivas; Simon. Jayaraj
Abstract: A solar hybrid energy system having photovoltaic and thermal (PV/T) devices, which produces both thermal and electrical energies simultaneously is considered for analysis. A double pass hybrid solar air (PV/T) heater with slats is designed and fabricated to study its thermal and electrical performance. Air as a heat removing fluid is made to flow through upper and lower channels of the collector. The collector is designed in such way that the absorber plate is partially covered by solar cells. The raise in temperature of the solar cell is expected to decrease its electrical performance. Thin metallic strips called slats are attached longitudinally at the bottom side of the absorber plate to improve the system performance by increasing the cooling rate of the absorber plate. Thermal and electrical performances of the whole system at varying cooling conditions are also presented.
Keywords: Double Pass; Energy; Photovoltaic; Solar Air Heater; Slats
Authors: Jianhua Zhang; Cheng Jiang; Lei Yu; Dexian Liu; Yunkai Weng; Xinwei Wang
Abstract: The conventional deterministic methods have been unable to accurately assess the active power of wind farm being the random and intermittent of wind power, and the probabilistic methods have been commonly used to solve this problem. In this paper the multi-state fault model is built considering running, outage and derating state of wind turbine, and then the reliability model of wind farm is established considering the randomness of the wind speed, the wind farm wake effects and turbine failure. The probability assessment methods and processes of wind farm active power based on the Sequential Monte Carlo (SMC) method are given. The related programs are written in MATLAB, and the probability assessment for wind farm active power is carried out, the effectiveness and adaptability of the proposed reliability models and assessment methods are illustrated by analysis of the effects of reliability parameters and model parameters on assessment results.
Keywords: Wind Farms; Multi-state Fault Model; Probability Assessment; Sequential Monte Carlo Method
Authors: Abdul Majeed Muzathik
Abstract: Accurate information on the intensity of solar radiation at a given location is essential to the development of solar energy-based projects. This information is used in the design of a project, in cost analysis, and in calculations on the efficiency of a project. As the solar radiation data are not available for most areas in Malaysia, this study is crucial in establishing the solar data for Terengganu, Malaysia. The geographical co-ordinates of the site are 50 10’ N latitude 1030 06’ E longitude and 5.2 m altitude. The data used in the present study were collected from the Renewable Energy Station, University Malaysia Terengganu from 2004 to 2010. In addition to these data, secondary data were obtained from Malaysian Meteorological Department from 2004 to 2009 at the Terengganu Airport station (5o 10.0’ N latitude 103o 6.0’ E longitude) which is nearly 2 km southeast to the study area. From the raw data, the mean, maximum and minimum hourly values were calculated. The highest 24 hours basis daily and monthly mean global solar radiation values were 314.9 W/m2 and 7556 Wh/m2/day, respectively. The highest hourly average solar radiation intensity was 1139 W/m2 during this study period. Yearly average daily solar energy was 18.93 MJ/m2/day. Besides the global solar radiation, the clearness indexes and air temperature variation are discussed. This study indicates that Terengganu state has a strong solar energy potential.
Keywords: Clearness Index; Daily Mean Solar Radiation; Monthly Mean Daily Solar Radiation; Yyearly Average Daily Solar Energy
Authors: Samir Deshmukh; firstname.lastname@example.org S. Gawande; Lalit B. Bhuyar
Abstract: The research work carried out so far in the field of solar desalination is related to the single basin type solar still only. The effect of changes in design, climatic and operational parameters on the distillate yield has been studied but limited to the single basin type solar still. The increase in productivity by connecting a flat plate collector which is called as active solar desalination has also been studied but limited to the single basin type solar still. Present study deals with a stepped type solar still to improve the performance of single basin type solar still by increasing the production rate of distilled water. The modifications in the design of single basin type solar still are introduced by replacing the flat basin by a stepwise structure. The stepped type solar still selected in this case has 8 number of steps of size 620 mm(L) x 100 mm(W) and total absorber area equal to 0.5093 m2. The characteristic feature of stepped type solar still is that it provides an additional 40% absorber area as compared to the single basin type solar still. In this work, three number of stepped type solar stills with varying depth of water and other design parameters like thickness of glass cover, insulation thickness, condensing cover material, shape of the absorber surface, absorbing material provided over the basin surface, angle of inclination of the still etc. being fixed have been selected for experimentation. The depth of water provided in solar stills A, B and C was 5 mm, 7.5 mm and 10 mm respectively. After conducting experiments for the varying depths of water, it has been observed that the distillate yield of solar still A is greater than solar still B and C by 14.15% and 22.64% respectively. Thus, as depth of water goes on increasing, the distillate yield produced per unit area of absorber surface goes on decreasing. Also, an economic analysis was made. The payback period of solar still A, B and C is 823 days, 958 days and 1064 days respectively. Thus, the solar still A with 5 mm depth of water gives the returns within the least possible time as compared to other two types of stepped solar stills.
Keywords: Stepped Type Solar Still; Depth of Water; Distillate Yield; Thermal Performance
Authors: Md. Imran Hossen Khan; Hasan M.M. Afroz; Md. Abdur Rohoman; Mohammad Faruk; Mohammad Salim
Abstract: This research work presents the experimental investigation of the effects of number of door opening; duration of door remaining open, ambient temperature and thermal load on the energy consumption of a household refrigerator. The experiments were conducted under the condition that number of door opening varied from 2 to 8 times per hour whereas the duration of door remaining open varied from 10 to 40 sec. The test has been carried out under the condition that the ambient temperature varied from 20 to 330C at different thermal loads varying from 0.001 m3 to 0.007 m3 of fresh water; each experimental run time was 6 hours. From the test results, energy consumption of refrigerator with door opening was found to increase compared to the same product without door opening. Depending on the number of door opening about 7% to 30% more energy consumption has been observed as compared to closed door condition. The test result also shows that a significant amount of energy consumption increases because the time of door remaining open increases. Depending on the time of door remaining open the energy consumption varied from 3% to 20%. The experimental result also confirms that the energy consumption increases by about 15% to 53% because the ambient temperature increases from 20 to 330C. The test result also proves that a significant amount of energy consumption increases because cabinet load (thermal load) increased. Depending on the different thermal loads about 18% to 59% more energy consumption has been observed as compared to non-load condition. If the users be serious, a significant amount of energy could be saved with proper utilizing of the refrigerator-freezer.
Keywords: Household Refrigerator; Door Opening; Ambient Temperature; Thermal Load; Energy Consumption