scholarly journals The efficiency of linear Fresnel reflectors in producing superheated steam for power plant drive

2021 ◽  
Vol 323 ◽  
pp. 00011
Author(s):  
Mokhtar Ghodbane ◽  
Marek Majdak ◽  
Boussad Boumeddane

Solar energy is one of the most important sources of renewable energies, which is widely used in many fields, such as electricity production through direct production of superheated steam based on Linear Fresnel Reflector. This study aims to show the optical and thermal behavior of linear Fresnel solar reflectors field directed to the electricity production in El-Oued region at Algeria. Four days of different weather data have been selected to track the change in solar field performance. Numerical optical modeling has shown that the optical performance of the solar field has reached 53.60 %, while the thermal study based on the numerical solution of the energy balance equations of the receiver tube proved that the thermal efficiency was 37.3 % and the average thermal loss coefficient was limited between 5.72 and 5.98 W/m²K. As for the superheated steam temperature, the lowest value was recorded in December with a value of 501 K. The results obtained are very compelling and encouraging to invest in this low-cost technology.

2021 ◽  
Vol 77 (3) ◽  
pp. 6-14
Author(s):  
Segundo Rojas Flores ◽  
Renny Nazario-Naveda ◽  
Daniel Delfín-Narciso ◽  
Moises Gallozo Cardenas ◽  
Natalia Diaz Diaz ◽  
...  

This research proposes an alternative for companies and farmers through the production of electricity using microbial fuel cells (MFCs) using waste from export products. Nine MFCs were manufactured with zinc and copper electrodes; and as substrates, pineapple, potato and tomato pulp wastes were used in the anode chamber, and residual sludge in the cathode chamber. It was observed that the MFCs with pineapple substrate generated higher values of the electrical parameters, resulting in voltage and current values of 0.3484 ± 0.003 V and 27.88 ± 0.23 mA, respectively. It was also observed that the maximum power density was 0.967 ± 0.059 W/cm2 at a current density of 0.04777 A/cm2 for the same substrate. Acid pH values were observed in the three samples, while the conductivity reached its maximum value on day 23 (69.47 ± 0.91 mS/cm) which declined until the last day of monitoring; the turbidity values increased abruptly after day 22 until the last day where a value of 200.3 ± 2.52 UNT was observed for the pineapple substrate. The scanning electron microscopy for the pineapple substrate MFC electrodes shows the formation of a porous biofilm on the zinc and copper electrodes. These results show that a new form of electricity production has been achieved by generating high voltage and current values, using low-cost materials.


Author(s):  
Siti Nazahiyah Rahmat ◽  
◽  
Algheethi Adel Ali Saeed Abduh ◽  
Ahmad Zurisman Mohd Ali ◽  
Mohd Adib Mohammad Razi ◽  
...  

1989 ◽  
Vol 111 (3) ◽  
pp. 193-203
Author(s):  
James A. Dirks ◽  
Clement J. Chiang

Typically, solar thermal power plants are designed to minimize the levelized energy cost. However, to maximize the benefit of a solar plant and, hence, maximize the wealth of an investor or a utility, a solar plant should be designed and operated with the objective of maximizing the value-to-cost ratio. This paper describes a value and cost analysis of solar central receiver power plants using molten salt external receiver technology. These plants were assumed to operate within the service area of the Southern California Edison Company. The SOLERGY computer code was used to simulate the performance of the solar plants using 1984 weather data for Barstow, California. A value-maximizing dispatch strategy that uses thermal storage to shift operation of the turbine from nonpeak demand periods to the utility’s peak demand period, is shown to greatly increase the value of a solar central receiver power plant with little increase in the levelized energy cost. Results are presented as functions of storage capacity, type of dispatch strategy, size of the field relative to the turbine, and turbine size.


Author(s):  
Michael J. Wagner ◽  
Guangdong Zhu

This paper presents the technical formulation and demonstrated model performance results of a new direct-steam-generation (DSG) model in NREL’s System Advisor Model (SAM). The model predicts the annual electricity production of a wide range of system configurations within the DSG Linear Fresnel technology by modeling hourly performance of the plant in detail. The quasi-steady-state formulation allows users to investigate energy and mass flows, operating temperatures, and pressure drops for geometries and solar field configurations of interest. The model includes tools for heat loss calculation using either empirical polynomial heat loss curves as a function of steam temperature, ambient temperature, and wind velocity, or a detailed evacuated tube receiver heat loss model. Thermal losses are evaluated using a computationally efficient nodal approach, where the solar field and headers are discretized into multiple nodes where heat losses, thermal inertia, steam conditions (including pressure, temperature, enthalpy, etc.) are individually evaluated during each time step of the simulation. This paper discusses the mathematical formulation for the solar field model and describes how the solar field is integrated with the other subsystem models, including the power cycle and optional auxiliary fossil system. Model results are also presented to demonstrate plant behavior in the various operating modes.


Author(s):  
Monica Subashini M ◽  
Sreethul Das ◽  
Soumil Heble ◽  
Utkarsh Raj ◽  
R Karthik

<p>About 10% of the world’s workforce is directly dependent on agriculture for income and about 99% of food consumed by humans comes from farming. Agriculture is highly climate dependent and with global warming and rapidly changing weather it has become necessary to closely monitor the environment of growing crops for maximizing output as well as increasing food security while minimizing resource usage. In this study, we developed a low cost system which will monitor the temperature, humidity, light intensity and soil moisture of crops and send it to an online server for storage and analysis, based on this data the system can control actuators to control the growth parameters. The three tier system architecture consists of sensors and actuators on the lower level followed by an 8-bit AVR microcontroller which is used for data acquisition and processing topped by an ESP8266 Wi-Fi module which communicates with the internet server. The system uses relay to control actuators such as pumps to irrigate the fields; online weather data is used to optimize the irrigation cycles. The prototyped system was subject to several tests, the experimental results express the systems reliability and accuracy which accentuate its feasibility in real-world applications.</p>


2021 ◽  
Author(s):  
Nadia Ameli ◽  
Olivier Dessens ◽  
Matthew Winning ◽  
Jennifer Cronin ◽  
Hugues Chenet ◽  
...  

Abstract Finance is vital for the green energy transition, but the access to low cost finance is uneven as the cost of capital differs substantially between regions. This study shows how modelled decarbonisation pathways of developing economies are disproportionately impacted by assumptions around their cost of capital (WACC). For example, representing regionally specific WACC values indicates 35% lower green electricity production in Africa for a cost-optimal 2°C pathway. Moreover, results show that early convergence of WACC values for green and brown technologies in 2050 would allow Africa to reach net-zero emissions approximately 10 years earlier than when convergence is not considered. A “climate investment trap” arises for developing economies when climate-related investments remain chronically insufficient. Elements of sustainable finance frameworks currently present barriers to these finance flows and radical changes are needed so that capital is better allocated to the regions that most need it.


Author(s):  
L.P.S.S.K. Dayananda ◽  
A. Narmilan ◽  
P. Pirapuraj

Background: Weather monitoring is an important aspect of crop cultivation for reducing economic loss while increasing productivity. Weather is the combination of current meteorological components, such as temperature, wind direction and speed, amount and kind of precipitation, sunshine hours and so on. The weather defines a time span ranging from a few hours to several days. The periodic or continuous surveillance or the analysis of the status of the atmosphere and the climate, including parameters such as temperature, moisture, wind velocity and barometric pressure, is known as weather monitoring. Because of the increased usage of the internet, weather monitoring has been upgraded to smart weather monitoring. The Internet of Things (IoT) is one of the new technology that can help with many precision farming operations. Smart weather monitoring is one of the precision agriculture technologies that use sensors to monitor correct weather. The main objective of the research is to design a smart weather monitoring and real-time alert system to overcome the issue of monitoring weather conditions in agricultural farms in order for farmers to make better decisions. Methods: Different sensors were used in this study to detect temperature and humidity, pressure, rain, light intensity, CO2 level, wind speed and direction in an agricultural farm and real time clock sensor was used to measured real time weather data. The major component of this system was an Arduino Uno microcontroller and the system ran according to a program written in the Arduino Uno software. Result: This is a low-cost smart weather monitoring system. This system’s output unit were a liquid crystal display and a GSM900A module. The weather data was displayed on a liquid crystal display and the GSM900A module was used to send the data to a mobile phone. This smart weather station was used to monitor real-time weather conditions while sending weather information to the farmer’s mobile phone, allowing him to make better decisions to increase yield.


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