Performance of a Solar Chimney With a Modified Collector Geometry: A Case Study From Erbil to the North of Iraq

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Dara Khalid Khidhir ◽  
Soorkeu A. Atrooshi
Keyword(s):  
Solar Radiation ◽  
Ambient Temperature ◽  
Temperature Difference ◽  
Mechanical Energy ◽  
Maximum Temperature ◽  
Geometrical Shape ◽  
Solar Chimney ◽  
Air Velocity ◽  
Temperature Loss ◽  
Solar Intensity

Abstract The principle of solar chimney power plant (SCPP) is based on harvesting the thermal spectrum of solar radiation and converting it to mechanical energy by the means of a collector, a wind turbine, and a chimney. In this work, a number of experiments were performed on a modified model made up of one-third of the circular collector area. Field data from selected clear, sunny days were recorded and studied. The analysis focused on time-temperature relations for ambient, near chimney entry point and the collector periphery, in addition to hourly solar radiation intensity and air velocity inside the chimney. The results show that for this geometry arrangement, the maximum temperature of the air entering the chimney is achieved before the ambient temperature reaches its peak value. Air velocity inside the chimney depends on the intensity of solar radiation and the temperature difference between the air temperature entering the chimney and the ambient temperature. Solar intensity directly affects the temperature of air beneath the collector, and a part of this energy is stored in the ground. Later, when the solar radiation is impaired, the stored energy can be utilized. Air velocity of 2.1 m/s is obtained after the solar noon, when the solar intensity is 737 W/m2 and the maximum temperature difference is 11.2 °C. Due to the unique geometrical shape of the rig, a minor temperature loss of up to 1.3 °C occurs for the air near the center of the chimney.

Experimental and Theoretical Investigation of Performance of a Solar Chimney Model, Part I: Experimental Investigation

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Essaied M Shuia ◽  
Bashir H Arebi ◽  
Ibrahim A abuashe
Keyword(s):  
Experimental Data ◽  
Wind Speed ◽  
Solar Radiation ◽  
Air Temperature ◽  
Solar Collector ◽  
Experimental Results ◽  
Internal Diameter ◽  
Solar Chimney ◽  
Air Velocity ◽  
Collector Temperature

This paper presents the experimental data that was collected from small pilot solar chimney. The experimental data together with ambient conditions are used to evaluate the performance and study the behavior of the solar chimney; this data will be used for comparison with theoretical models in another paper [part II). The solar chimney prototype was designed and constructed at the Subrata Faculty of Engineering-Libya. The data were collected over several days of June 2011. The solar chimney system contains two main components; the solar collector and the solar chimney. The solar collector root‘ has a circular area of126 m3, the solar chimney is a PVC tube with internal diameter of 0.2 m and the total height of chimney is 9.3 m. The measurements include the intensity of solar radiation inside/outside the collector, temperature and velocity of air at the entrance of the chimney, temperature and speed of wind outside the collector, temperature of the ground inside collector al1d temperature measurements of air at speci?c points at different levels throughout the collector. Solar irradiance was found to affect the chimney temperature and subsequently affects chimney air velocity. The experimental results showed that temperature differences of (30 - 45°C) were recorded between the ambient temperature and that of air inside the chimney in the middle of the day, where the highest air temperature of 73.4°C was recorded at the entrance of the solar chimney. The maximum air velocity of 3.6 m/s was recorded inside the solar chimney at noon on 9 June. Wind speed outside the collector had a small effect on the speed of the air inside the chimney and tends to change slightly, hence, can neglect influence of wind speed on the performance of the system. Also the experimental results indicate that such type of system can trap a suf?cient amount of solar radiation, which elevates the air temperature to a suf?cient value able to generate enough air ?ow to operate a wind turbine to produce electricity; this means the solar chimney system for electricity production can work in the north-western part of Libya in the summer time at least.

Solar Chimney Power Plant Performance for Different Seasons Under Varying Solar Irradiance and Temperature Distribution

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Ulku Ece Ayli ◽  
Ekin Özgirgin ◽  
Maısarh Tareq
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Ambient Temperature ◽  
Solar Irradiance ◽  
Power Plants ◽  
Low Cost ◽  
Renewable Energy Sources ◽  
Three Dimensional ◽  
Plant Performance ◽  
Solar Chimney

Abstract One of the most promising renewable energy sources is solar energy due to low cost and low harmful emissions, and from the 1980s, one of the most beneficial applications of solar energy is the utilization of solar chimney power plants (SCPP). Recently, with the advancement in computer technology, the use of computational fluid dynamics (CFD) methodology for studying SCPP has become an extensive, robust, and powerful technique. In light of the above, in this study, numerical simulations of an SCPP through three-dimensional axisymmetric modeling is performed. A numerical model is created using CFD software, and the results are verified with an experimental study from the literature. The amount of solar radiation and surrounding weather (ambient temperature) were analyzed, and the effects of the irradiance and air temperature on the output power of the SCPP were studied. Ambient temperature is considered as one of the most important factors that influence collector efficiency in a negative or a positive manner. Solar irradiance is considered to be the most important factor that has an impact on SCPP performance. The investigation includes the study of the relationship between solar insolation and ambient temperatures during the daytime since the difference between the minimum and maximum power values and the performance are very important considering seasonal changes. According to the results, power values are dependent on the amount of solar radiation as well as the ambient temperature, and the importance of selection of location thus climate for an SCPP is found to affect the design of the SCPP.

scholarly journals The Effect of Solar Chimney Dimensions on its Performance in Nasiriya City Weather Conditions

2018 ◽  
Vol 7 (4.19) ◽  
pp. 824
Author(s):  
Rafid M. Hannun ◽  
Hussein Togun ◽  
Mohammed H. Khalaf ◽  
Tariq M. Abed
Keyword(s):  
Solar Radiation ◽  
Solar Collector ◽  
Numerical Study ◽  
Weather Conditions ◽  
Ambient Air ◽  
Previous Literature ◽  
Solar Chimney ◽  
Air Velocity ◽  
Analytical Results ◽  
Air Intake

In this study, a numerical study was carried out on the effect of the solar chimney dimensions on its performance. Five different models of solar chimney were studied in terms of the diameter of the solar collector, the height of the air intake entrance of the collector and the height of the solar chimney. The five models were compared with others according to the conditions surrounding the solar chimney. The study showed that the increase in the dimensions of the solar chimney increases the utilized energy and the external air velocity is inversely proportional to the performance of the solar chimney due to increasing the thermal losses from the collector. The results showed also that increasing the temperature of the ambient air and the solar radiation increases the performance and productivity of the solar chimney. The analytical results of this paper were compared with previous literature studies and showed a great convergence between them.  

scholarly journals Improvement Approach for Matching PV-array and Inverter of Grid Connected PV Systems Verified by a Case Study

2021 ◽  
Vol 10 (4) ◽  
pp. 687-697
Author(s):  
Moien A. Omar ◽  
Marwan M. Mahmoud
Keyword(s):  
Solar Radiation ◽  
Ambient Temperature ◽  
Output Power ◽  
Peak Power ◽  
Maximum Temperature ◽  
Voltage Range ◽  
Pv Array ◽  
High Solar Radiation ◽  
Pv Modules

Correct matching between PV array and inverter improves the inverter efficiency, increases the annual produced energy, decreases the clipping losses of the inverter, and prevent to a large extent the inverter frequent shut downs during clear sunny days of high solar radiation and low ambient temperature. Therefore, this paper presents a new methodology for selecting the appropriate peak power of the PV array with respect to the inverter output AC rated power taking into account the local daily distribution of solar radiation and ambient temperature. In addition, the proposed methodology specifies the appropriate number of PV modules in each string and the number of parallel strings connected to the input of the inverteraccording to its specifications and to PV cell temperature. Mathematically modeling of system parameters and components are presented and used in the simulation to investigate the different scenarios. The paper presents also a case study using simulation to find the optimal matching parameters of a PV array connected to an inverter with the specifications: 6 kW rated output power, an input mpp voltage range of 333-500 V, 6.2 kW maximum input DC power, and an output AC voltage of 230 Vrms. Considering the local climate conditions in West Bank, the simulation resulted a peak power of 7 kW for the PV array, which is greater than the inverter output power by the factor 1.16. In addition, the obtained PV array consists of two parallel strings each includes 12 PV modules  connected in series  while each PV module is rated at 290 W. The output voltage of the PV arrayvaries between 359 V to 564 Vat minimum and maximum temperature of 10 ˚C to 70 ˚C respectively. This PV array-inverter combination resulted by simulation an annual yield of 1600 kWh/kWp and an energy of 11197 kWh which corresponds to an energy gain of 1591 kWh/year more than using a PV array with a peak power of 6 kW as the inverter rated power.

Design and Experiment of a Concentrating Transpired Air Heating System

2011 ◽  
Author(s):  
N. Shams ◽  
M. Mc Keever ◽  
S. Mc Cormack ◽  
B. Norton
Keyword(s):  
Solar Radiation ◽  
Ambient Temperature ◽  
Heating System ◽  
Maximum Temperature ◽  
Optical Efficiency ◽  
Incident Solar Radiation ◽  
Air Heating ◽  
Significant Temperature ◽  
Ray Tracing Model ◽  
Absorber Surface

This paper presents the physical design and experiments of the Concentrating Transpired Air Heating (CTAH) system as a combination of subsystems of parabolic primary and circular secondary reflector that concentrates incident solar radiation onto an inverted perforated absorber. Optical efficiency of the CTAH system has been analysed using a 2D ray tracing model. Experiments have been carried out for 50% perforated black painted aluminium inverted absorber for glazed and unglazed systems. Results show a significant temperature rise of the absorber surface in both cases. The maximum temperature of the absorber for the unglazed system is 52.1°C at 22.5°C ambient temperature, where as for the covered system, it is 67.9°C at 23.2°C ambient temperature.

Research on Temperature Field of CFST Member under Solar Radiation

2012 ◽  
Vol 204-208 ◽  
pp. 3164-3168 ◽  
Author(s):  
Jun Ling Fan ◽  
Hong Cai Zheng ◽  
Qian Zhang ◽  
Man Ding ◽  
Yan He
Keyword(s):  
Heat Flux ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Solar Radiation ◽  
Ambient Temperature ◽  
Temperature Difference ◽  
Steel Tube ◽  
Peak Temperature ◽  
Center Point

This study concerns the experimental and numerical researches on the temperature field of CFST which is subjected to periodic solar radiation and ambient temperature. The study gives the detailed temperature and heat flux which vary with time, and the results indicate that temperature distribution caused by solar radiation is nonlinear, and is significantly varied with time and sections. The peak temperature of measure points in the surface of steel tube and in the center of concrete occur at different times, the largest temperature difference is over26.3°C. The variations of temperature lag obviously when the measuring points are more close to center in the same series. And the temperature of the center point is affected by various directions, especially the strongest direction.

Simulation Evaluation of Fouled Ballast Thermal Characteristics

2020 ◽  
Author(s):  
Yongwen Tan ◽  
Yang Chen ◽  
Sayed-Mohammad Hosseini ◽  
Mehdi Ahmadian
Keyword(s):  
Thermal Behavior ◽  
Ambient Temperature ◽  
Temperature Difference ◽  
Thermal Characteristics ◽  
Maximum Temperature ◽  
Conductive Heat ◽  
Maximum Temperature Difference ◽  
Temperature Changes ◽  
Simulation Evaluation ◽  
Fouled Ballast

Abstract This study provides a simulation evaluation of the effect of fouling conditions on the thermal behavior of ballast for the use of railway tracks. Ballast fouling can result in a slurry pumped up to the surface, causing poor foundation strength, rotting of the ties, and other ill effects. To achieve a quick and convenient detection of ballast fouling, a thermal-based non-contacting technique has been proposed and becomes more and more attractive. However, the successful application of this thermal-based fouling-detection technology requires knowledge of the thermal characteristics of ballast, which have not been investigated in prior studies. The objective of this paper is to study the influence of fouling on the thermal behavior of ballast, using an analytical model developed based on one-dimensional conductive heat transfer. The effort to validate the developed model is also included. The general fouling conditions of the ballast — fouled with and without water — are studied through simulation. The simulation results show that, for the case of fouling without water, the ballast under different fouling conditions behaves differently from clean ballast at depths ranging from 0 to 12in under naturally-occurring daily ambient temperature changes, and that the temperature difference peaks at 4-in depth. In addition, increasing the amount of fouling results in less temperature variation in response to the ambient temperature changes. For the case of fouling with water, water is added into the 100% fouled ballast and comparisons are made between the ballasts with different water content. A similar pattern is observed, showing that increasing the amount of water results in a larger temperature difference at all depths considered. Moreover, the maximum temperature difference is observed at the top surface rather than the depth of 4-in as observed in the case of fouling without water.

Unsteady Conjugate Numerical Simulation of the Solar Chimney Power Plant System with Vertical Heat Collector

2011 ◽  
Vol 704-705 ◽  
pp. 535-540 ◽  
Author(s):  
Yan Zhou ◽  
Xiao Hui Liu ◽  
Qing Ling Li
Keyword(s):  
Numerical Simulation ◽  
Power Plant ◽  
Solar Radiation ◽  
Output Power ◽  
Maximum Output Power ◽  
Maximum Output ◽  
Solar Chimney ◽  
Air Velocity ◽  
Heat Collector ◽  
Solar Chimney Power Plant

A new kind of solar chimney power plant system combining chimney and heat collector was designed. Paraffin was chosen as the material of energy storage layer and the unsteady conjugate numerical simulation of the system was done by Fluent software. The operation condition of the system was simulated when the solar radiation value was changed with time according to the actual situation. Simulation results showed that: with the increase of solar radiation, flow velocity of the air and the maximum output power increased. At twelve o'clock, the air velocity could reach 1.24 m/s and output power was 122W. Due to the energy storage effect of phase change materials, the system had output power of 1.3W at night. Moreover because of the continuous work of the heat storage layer, in the same condition of solar radiation, the air velocity and maximum output power increased with the system operation days extended.

Bacterial die-away rates in red sea waters

1995 ◽  
Vol 32 (2) ◽  
pp. 45-52 ◽  
Author(s):  
H. Z. Sarikaya ◽  
A. M. Saatçi
Keyword(s):  
Solar Radiation ◽  
Decay Rate ◽  
Sea Water ◽  
Membrane Filter ◽  
Linear Regression Analysis ◽  
Total Coliform ◽  
Coliform Bacteria ◽  
Decay Rate Constant ◽  
Solar Intensity ◽  
Log Normal

Total coliform bacteria have been chosen as the indicator organism. Coliform die-away experiments have been carried out in unpolluted sea water samples collected at about 100 m off the coastline and under controlled environmental conditions. The samples were transformed into one litre clean glass beakers which were kept at constant temperature and were exposed to the solar radiation. The membrane filter technique was used for the coliform analysis. The temperature ranged from 20 to 40° C and the dilution ratios ranged from 1/50 to 1/200. Coliform decay rate in the light has been expressed as the summation of the coliform decay rate in the dark and the decay rate due to solar radiation. The solar radiation required for 90 percent coliform removal has been found to range from 17 cal/cm2 to 40 cal/cm2 within the temperature range of 25 to 30° C. Applying the linear regression analysis two different equations have been given for the high (I>10 cal/cm2.hour) and low solar intensity ranges in order to determine the coliform decay rate constant as a function of the solar intensity. T-90 values in the light have been found to follow log-normal distribution with a median T-90 value of 32 minutes. The corresponding T-90 values in the dark were found to be 70-80 times longer. Coliform decay rate in the dark has been correlated with the temperature.

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