Thermo-hydrodynamic Airflow Behavior Analysis in Solar Chimney Device

Analysis of some available heat transfer coefficients applicable to solar chimney power plant collectors

Solar chimney power plant (SCPP) is one of the promising technologies for solar energy utilization. It is an interesting system especially in large isolated desert areas due to its basic techniques and low operating costs. In this study, we investigate numerically the collector geometrical parameters effect on the hydrodynamic flow control in a solar chimney. The finite volume method and the SIMPLE algorithm have been used to solve the turbulent flow equations and energy equation. A standard K-? model is used. The influence of the collector height (0.05m?Hc?0.5m) and the collector radius (2.5m?Rc?15m) on the flow behavior has been numerically analyzed. The obtained results indicate that increasing the collector height and collector radius affect considerably the flow behavior and the SCPP performance. The mass flow rate is enhanced by about 27 %, for Rc=12.5m and Hc = 0.25m.

It is important to analyze the variables influencing the performance of the solar chimney power plant (SCPP) according to output power as well as efficiency. The most important of these variables is the geometric dimensions, solar radiation intensity, and ambient temperature. In this experimental and numerical study, a prototype with variable dimensions was manufactured. A theoretical study was presented by creating a numerical model that helps in analyzing the governing equations, such as the continuity, momentum, and energy equations, in addition to the turbulence model equations (k–ε). The calculations show the influence of chimney height, diameter, solar collector diameter, inlet collector gap, temperature, and solar radiation on the SCPP performance. These variables were also tested experimentally, and the effect of each variable on the efficiency and output power was demonstrated. The maximum velocity was at the turbine exit, about 18.5 m/s in the case of the Spanish model, while it was 2.2 m/s for the present prototype. The maximum temperature value was 333 K for the Spanish model at a collector radius ratio of 3. The maximum output power was 156 mW for the Spanish model. For the current prototype, the maximum airflow temperature was 67 °C when the chimney height was 3 m; by decreasing the chimney height to 2.5 and 2 m, the maximum temperature decreased to 63 and 54 °C, respectively, which are about 6.5% and 19% deterioration. The results show that the relationship between the output power and any of the geometric dimensions is direct. The overall efficiency relationship is direct with the height and diameter of the chimney and inverse with the diameter of the collector and the height of the collector entrance. The output power rises with increasing solar radiation and slightly drops with increasing ambient temperature. The reliability of the numerical solution was verified by comparing the numerical and experimental results, as well as the data of the Spanish model. The agreement was satisfactory, with the mean percentage error (MPE) not exceeding 1.5% for all performance parameters.

Solar chimney power plants (SCPP) exploit solar radiation to create an up-draft airflow to run a turbine. This article proposes an innovative design of an SCPP that consists of transparent glass covered solar collector. Outdoor experiments have been carried out in the arid climates of Tikrit city, Iraq, with galvanized metal tower installed instead of conventional PVC solar towers. Performance of the SCPP has been studied with and without transparent cover for collector periphery heights of 2 and 4 cm. Measurements of ambient temperature, chimney inlet temperature, interior and outlet air temperatures, humidity, air mass flow rate, and solar irradiance values were recorded from 9:00 am to 4:00 pm throughout the month of May 2021. Results show that the solar chimney collector with a periphery height of 2 cm performed better than that with the 4-cm periphery height. In addition, using transparent cover in SCPP increases the air outlet temperature by 16.4°C and air flowrate augments by around 34%. Thermal efficiency of the solar chimney with non-covered tower is found to be 10.3% whereas for a glass covered tower it increases to 14.6%, which is a remarkable 41% enhancement. Likewise, mechanical and electrical power output augment by 39.6% and 40.3% using transparent cover in SCPP. Such innovation in SCPP design is proven apposite for hot arid climates.

Integrating solar chimney power plant with electrolysis station for green hydrogen production: A promising technique

Numerical study on the performance of a solar chimney power plant

The aim of the work presented in this study is related to solar chimneys energy performances determination, and flow modelling analysis, according to certain dominant parameters. The analysis of the problem presented in this paper is structured into two parts: the first one, is corresponding to energy calculation, for the prediction of the performances, such as the output and the power delivered by a solar chimney power plant (SCPP), according to some geometrical and physical parameters, such as the height and the solar radiation. The second one is related to the modelling of the air flow in the chimney. It consists, in analysing a natural convective heat transfer problem, that take place in a solar chimney plant were the thermo- hydrodynamic aspects of the air flow through an axis symmetric system with well defined boundary conditions is examined. Obtained results are related to the temperature, and the velocity distributions in the device were they are determined by solving the energy and the Navier and Stokes equations, by using the finite volume method. A specific consideration is given to identify the adequate position, in order to choose, and to optimize the site of the wind turbine in the chimney.

The solar chimney power plant is a promising system to generate electrical power from free solar energy. The analysis was carried out to improve the description of the operation mode and efficiency. The solar collector, chimney and turbine are modeled together theoretically, and iteration techniques were then carried out to solve the mathematical model developed. This model was developed to estimate power output of solar chimneys as well as to examine the effect of solar heat flux and structural dimensions on the power output. Results from the mathematical model were validated by measurements from the physical plant actually built and the model was further used to predict the performance characteristics of large-scale commercial solar chimneys. The results show that the plant size, the factor of pressure drop at the turbine and the solar heat flux are the important parameters for the performance enhancement.

Study on the Performance of a solar chimney power plant chlef, Algeria region was presented in this work. The solar chimney is used in hot areas such as Chlef with high intensity of solar radiation. In this work, the solar chimney power plant (collector, chimney and turbine) is modeled theoretically, and the global solar radiation, the air temperature was measured during the period of 01/01/2015 to 1/06/2016. The model is employed in simulation to predict the electrical power produced by the solar chimney plant using the meteorological data of Chlef region. The effect of the geometrical parameters on the performances of the solar chimney power plant was studied. The influence of chimney height on electrical power produced is simulated in order to have the optimum SCPP to respond to the electricity demand in Chlef region. The performance characteristics of solar chimneys indicate that the dimensions of the chimney (height of the chimney, diameter of the collector, height of the collector and the diameter of the chimney) and the climatic condition (air temperature and solar radiation) are important parameters in the production of electrical energy.

ABSTRACTSolar chimney power plants constitute an impressive construction by its size and its output seems low for its dimensions. Although many works have been carried out on the subject, there is still much scientific and technical improvement to be done. In the present work, we consider the modeling of turbulent flow under the effect of natural convection within a solar chimney power plant (SCPP) by performing numerical simulation using the Saturne Code coupled with Syrthes code. The objective of the study is the analysis of the collector cover slope influence on the performance of the SCPP in two cases. In the first case, the storage system considered is composed solely of the ground under the collector. For the second case, the storage system is made, in addition to the ground, of a 10 cm thick tub filled with water, covering the entire surface of the collector. The concept of minimizing the entropy production is also studied with the objective of optimizing the geometric configuration as well as the effect of the collector cover slope on the efficiency of SCPP. The boundary conditions are defined according to the meteorological data for a typical day available on the site of Adrar, Algeria. The results allow us to focus on the storage system influence on the SCPP performance and the duration of its operation after sunset. This leads to the improvement of the global efficiency of the SCPP. Results show the positive impact of the extra storage media use and the configuration which improves the velocity at the chimney entrance.

A simple thermal model is developed for solar chimney thermal power system and validated by the comparison between the simulated results and those simulated by Schlaich et al. Based on a proposed 200 MW power plant in a desert in western China a special climate, which is formed around the giant solar chimney power plant by the volume of warm air flowing from the chimney outlet to a high altitude, is simulated and analyzed. An atmospheric circulation and rainfall are formed. It is found that the solar chimney power plant increases the chance of rainfall, especially for low-humidity air in the desert region, supporting the agriculture in the local area and promoting a part of the desert region to be reformed to fertile soil. Further, the effects of many factors on the rainfall area around a commercial solar chimney thermal power plant are also analyzed. It is concluded that by keeping other conditions equal, solar radiation of more than 706 W∕ m2 , a collector area of more than 10.45 km2 , a chimney height ...

Chapter 4 - Fluid flow and heat transfer of solar chimney power plant

Total global renewable energy capacity has been increasing worldwide, i.e. doubled from 2007 to 2016. The main disadvantage of most renewable energy based plants is the lack of reliability for constant electricity production. Solar chimney is a renewable based plant with a power production of near zero during the night times. In this study, we have proposed a renewable integrated cycle by combining two plants and thereafter produce a reliable amount of electricity all the time. The proposed combination is achieved by injecting outlet air from the condensers of Tehran’s waste to energy plant into the bottom of the chimney tower, just below the turbine. Tehran’s average climate data for 12 months of the year is initially obtained and the Manzanares prototype is used for the solar chimney power plant model. The solar chimney power plant is simulated with 3D CFD simulation. The final power output of the solar chimney power plant reaches 20–70 kW and increased 20%–1200%, compared to the case without injection. This means power output of solar chimney power plant is at least 20 kW in the hottest night of the year with 5% relative humidity. We have concluded that by combining these renewable based plants, one of the most important solar chimney disadvantages could be removed.

Recent developments and innovations in solar chimney power technologies: A focus on the last two decades

Numerical investigation of solar chimney power plants performance for Saudi Arabia weather conditions