As the need to transition towards renewable energies becomes increasingly evident and a grow-ing number of regions are subject to more intense water stresses, various power-generation and electricity-production technologies are being developed. Among these, the Solar Cyclone Tower (SCT) appears to be a promising solution, for both electricity and water production, which is based on a renewable energy source: sunlight.
In this thesis, the author explores the different features of the SCT technology, its operating concept and advantages. He also present a physical model which has been built for pedagogical uses. He discusses how the SCT’s water and electricity production can be enhanced. Potential facilities which the SCT could host are also considered and the solar tower’s overall advantages listed. We explain how various physical phenomena make environmental variables difficult to predict and challenging to probe. However, it is necessary to acquire real-time data on environmental variables such as temperature, humidity, insolation and airflow for a number of different reasons which he will discuss.
He has thus undertaken a study and review of different temperature, humidity, insolation and airflow sensing technologies which are suitable for use in the SCT. He later characterised a simple temperature and humidity sensing device and, finally, presented the outline of a sensor placement algorithm and a method to find the optimal number of sensors.
Table of Contents
1 Introduction
2 History and Context
2.1 History of the SCT
2.2 Manzanares prototype
2.3 Modern developement, Prototypes and projects
3 Presentation of the SCT
3.1 Operating concept
3.2 The SCT’s different components
3.3 Estimate of the collector’s energetic balance
3.4 Influence of the collector size and chimney height
3.5 Water-harvesting with a Solar Cyclone Tower (SCT)
3.5.1 Nucleation
3.5.2 Water production
3.5.3 Effect of water production on the updraft
3.6 Overview of the SCT under scrutiny
3.7 Choosing an optimum location
4 Opportunities and Advantages
4.1 Agriculture
4.2 Enhancing water harvesting
4.3 Heat and power management
4.3.1 Influence of the ground type
4.3.2 Enhancing soil energy storage
4.4 Food drying and extracting salts
4.5 Carbon Dioxide Capture
4.5.1 Methods
4.5.2 Vortex Tubes
4.6 Biofuels
4.7 Enhancing the collector roof with Organic Photovoltaics (OPVs)
4.8 Advantages
5 Building a Physical Model
5.1 Characteristics
5.2 Conception
6 Challenges in probing environmental variables
6.1 Thermal convection cells and irregularities
6.2 The effect of ambient crosswinds
6.3 Blockage walls to mitigate crosswind
7 Options and solutions for sensing environmental variables
7.1 Real-time data for an active SCT
7.1.1 Insulated storage tanks
7.1.2 Controllable windows
7.1.3 Panels to direct airflow
7.1.4 Controllable swirl vanes
7.2 Temperature
7.3 Humidity
7.4 Sensing airflow
7.5 Measuring solar irradiance
7.6 A simple sensor for humidity and temperature sensing
7.6.1 Layout
7.6.2 Temperature and humidity dependance of the HCZ
7.6.3 Characterisation of the LM35
7.7 Developing a model
8 Sensor placement
8.1 Placement Algorithm
8.2 Choosing the optimal number of sensors
9 Summary and Conclusion
Research Objectives and Core Themes
This thesis investigates the Solar Cyclone Tower (SCT) as a sustainable solution for simultaneous electricity generation and freshwater harvesting. The central research objective is to analyze the operational features of the SCT, address the challenges in predicting complex environmental variables within its structure, and develop an optimized sensor network strategy to monitor these variables effectively.
- Operating concepts and technical components of the Solar Cyclone Tower.
- Enhancement strategies for water harvesting and electricity production.
- Methods for thermal energy storage and management.
- Development of a sensor placement algorithm for environmental monitoring.
- Characterization of low-cost sensors for temperature and humidity.
Excerpt from the Thesis
3.5.1 Nucleation
Nucleation is the process of droplets formation in a condensed phase. Nucleation can occur in a clean environment (pure mixture), in which case it is referred to as homogeneous nucleation, or in a dusty mixture, in which case it is referred to as heterogeneous nucleation.
At the dew point, the air is saturated in water vapour. Temperature must then drop even further and reach a so-called subcooling state for the probability of condensation to exist. In an environment devoid of dust or aerosols (homogeneous nucleation), temperature would have to drop significantly below the dew point for the condensed phase to nucleate (form droplets) [1]. Once condensation has occured, the air parcel has to reach its saturated state again and undergo the same process again.
However, nucleation can be facilitated by the natural (or forced) presence of dust or biological aerosols in the SCT [96–101]. Indeed, in the case of a heterogeneous condensation, water condenses immediately at saturation and condensation continues to occur as the temperature lowers, keeping the mixture at saturation [1].
Nucleation can also be activated by the intentional introduction of aerosols, the use of highly oxygenated biogenic vapours [102] or bacteria and water condensation can be enhanced by the use of different water-harvesting technologies [103–107].
Summary of Chapters
1 Introduction: Provides an overview of the global energy and water crisis and introduces the SCT as a potential solution.
2 History and Context: Reviews the historical development of solar towers, focusing on the Manzanares prototype as a key milestone.
3 Presentation of the SCT: Details the operating principles of the SCT, its main components, and the physics behind water harvesting.
4 Opportunities and Advantages: Explores auxiliary benefits of the SCT, including agriculture, carbon capture, and biofuel production.
5 Building a Physical Model: Describes the design and construction of a small-scale model for pedagogical visualization of the SCT concept.
6 Challenges in probing environmental variables: Analyzes the difficulties caused by thermal convection and ambient crosswinds in monitoring the SCT.
7 Options and solutions for sensing environmental variables: Evaluates technological solutions for monitoring key variables and presents a characterization of a simple sensing module.
8 Sensor placement: Presents an algorithm to determine the optimal number and location of sensors within the tower.
9 Summary and Conclusion: Summarizes the findings and suggests paths for future research in monitoring and optimizing SCT performance.
Keywords
Solar Cyclone Tower, Renewable Energy, Water Harvesting, Sensor Network, Thermal Storage, CFD Simulation, Hydroponics, Carbon Capture, Environmental Monitoring, Solar Updraft Tower, Humidity Sensing, Temperature Measurement, Optimization Algorithm.
Frequently Asked Questions
What is the core focus of this research?
The research focuses on the Solar Cyclone Tower (SCT) as a multifunctional facility capable of producing both electricity and clean freshwater using solar energy.
What are the primary applications of the SCT technology?
Beyond power generation and water production, the SCT can host auxiliary facilities for agriculture (hydroponics), carbon dioxide capture, and the production of biofuels.
What is the main research question regarding sensor technology?
The work investigates how to efficiently monitor environmental variables like temperature, humidity, and airflow inside a massive structure, addressing the chaotic nature of these variables.
Which scientific method is primarily used in this thesis?
The thesis relies on a combination of theoretical analysis, reference to existing CFD (Computational Fluid Dynamics) models, and an experimental characterization of low-cost sensors.
What does the main part of the thesis cover?
The main part covers the operating principles of the SCT, methods to enhance production, the construction of a physical demonstration model, and a strategy for sensor deployment.
Which keywords best describe the paper?
Key terms include Solar Cyclone Tower, Water Harvesting, Sensor Network, CFD Simulation, and Thermal Energy Storage.
Why are crosswinds considered a significant challenge?
Crosswinds disturb the pressure profile at the tower base, which is crucial for buoyancy-driven power generation, potentially causing significant drops in energy and water production.
How does the proposed sensor placement algorithm work?
The algorithm uses variance-based mesh generation from CFD simulations to determine optimal sensor locations that maximize data quality for a given number of sensors.
What role does the proposed physical model play?
The physical model is designed for pedagogical and demonstration purposes, allowing observers to visualize the structure, the swirling airflow, and the process of water condensation.
- Quote paper
- Sina Varaei (Author), 2019, Features of the Solar Cyclone Tower Technology. Sensor Network for an Enhanced Solar Cyclone Tower, Munich, GRIN Verlag, https://www.grin.com/document/899767
