Development of a Solar Wind Downdraft Energy Tower

SUMMARY

I have done research on the renewable energy extraction plant- Solar Wind downdraft energy tower. This plant is most efficient in warm place, but it has low efficiency in cold temperatures. I have explained the components and design of the tower.

The tower can operate 24 hours and gives constant power supply. The updraft tower uses minimum space and has comparatively simpler design. It has turbines at base in the tunnels. The air pass through the turbines and creates electricity. The tower can predict the energy generation. We can choose the site for the tower by analytical software. It has better efficiency then the updraft wind tower.

Contents

SUMMARY

INTRODUCTION

Problem:

Background:

Purpose:

DISCUSSION

Design Methodology:

Design structure of turbine tunnels:

Pump and Nozzle selection:

Conclusion and Recommendation

References:

APPENDIX

Image of module 110 and definition

INTRODUCTION

Problem:

Renewable energy is the need of the new world. The energy extraction from conventional sources is becoming more and more expensive, and the causes are minimal now. The solar wind downdraft tower is the new approach for the need for renewable energy extraction. The updraft solar wind tower will use both solar and wind energy to generate electricity.

The updraft energy tower requires a large amount of land for collectors. It has a higher capital cost than the other types of energy extraction plants due to the levitated turbine structure. It also needs a high amount of electricity because the Collectors filling process takes up a lot of power. The downdraft tower has the most prominent advantage that it is tall but compact. It does not have collectors, so it is relatively simple in design.

Background:

Solar wind updraft tower has been built in mid of 2018 to extract energy using solar and wind combined. The updraft solar wind tower uses low-temperature solar heat to generate electricity. Sunshine heats the air near the ground in large greenhouse-like roofed collector structure surrounding the central base of a quite tall round shape tower. The resulting convection effect causes hot air to flow upward in the tower the same as the smoke chimney. This upward airflow drives the turbines which are placed in the chimney updraft tower or at the base, to produce electricity.

Shortly after that, Dr. Phillip Carlson came up with the new concept of downdraft solar wind energy tower. The idea expanded by Professor Dan Zaslavsky and Dr. Rami Guetta. The purpose of the solar wind tower is to generate electricity with a downward force of the air. The tall and wide hollow tower consists of the water spray system at the top. Pumps carry the water to the top of the tower and sprinkle fine mist inside the tower. Evaporation of water cools the air hovering inside the tower and make it denser. Now, cooled air thicker than the outside, warm air falls through the chimney and rotate the turbine at the bottom of the stack.

The use of updraft tower requires a lot of land for the collector, and a lot of electricity is wasted to fill the collectors, so another approach of downdraft tower is a better option where the area is limited.

The solar wind energy tower is an entirely new approach for electricity production. Solar wind downdraft tower can reduce the carbon footprint. The downdraft wind tower is new technology which needs a lot of research like cost, design, and location selection. This report will include a different aspect of the tower.

Purpose:

Even today a lot of the countries have so many power outages. Majority of the world’s electricity is still reliable on non-conventional resources. The renewable sources for electricity are limited and cannot produce as much energy to fulfill the requirement of a country. The focus of this project will be on efficiency, feasibility, and reliability of the downdraft solar wind energy tower. The discussion and concluding sections of this report will analyze the design, cost of construction, power generation capacity, and its limitation.

The concept of downdraft tower came into practice after 2016. Thus, there is not much information about the plant and its durability in working condition. The tower has different turbines which are developed only for them, which are quite complicated. Although researchers have built small-scale plants, there is no commercial plant yet. I have collected the data from the research thesis and company websites.

DISCUSSION

Design Methodology:

The tower has three main components.

• Nozzles for water spray.
• Pumps to lift water to the top.
• Turbines for power generation.

Figure 1.1  solar wind downdraft tower prototype model.

Source: Solar Wind Energy, Inc.

• The tower structure is a hollow cylindrical tall chimney and turbines are situated at its base.
• The base has different tunnels through which the air flow through the turbines.
• Each tunnel has three turbines and each turbine has two hydraulic lines connected.
• The top part of the tower has nozzles which spray water mist inside the tower.

Design structure of turbine tunnels:

Figure1.2 Wind tunnel 100 coupled to high efficiency hydraulic-to-electric converters under             variety of wind speed.

Source: patent US8120191B1, J. Hanback(retrieved from Solar Wind Energy Tower Inc)

• The tunnel has three turbines T1, T2, and T3.
• All the turbines connected to high-pressure line(HPL) and low-pressure line(LPL) via hydraulic to electric converters 110 and accumulator 120.
• A controller 130 which is connected to 110 is a triple-redundant dedicated processing system containing three separate central processing units (CPUs).

When air flows from T1 to T3 each turbine extract some of the energy with energy availability propositional to the cube of wind speed at each turbine T1-T3. If we assume that each turbine may extract 50% of the power, it is feasible that to make the swept area of the T2 half that of turbine T1 and make the swept area for T3 half that of T2 (patent US8120191B1, J. Hanback).

Pump and Nozzle selection:

• Pump selection is depended upon the height of the tower. If we assume that tower height is 1500 ft., we can select API 610 Process Pump with 1500 ft. head and 20,000 GPM capacity(pump selection guide, Goulds pumps)
• The nozzle used to atomize the water and spray it inside the tower. For this purpose, we can install automatic nozzle air actuated or electrically actuated(spraying system Co.).

Proprietary Global Energy Generation Calculator:

The Solar Wind Energy Inc. has developed analytical software which can put the energy tower variable data and with the help of scientific meteorology data of specific area can project the energy output in that area.

Using this software company has predicted the gross output energy for a site near San Luis, Arizona, has a total hourly production capacity of 1250 megawatt hour. (Solar Wind Energy Tower Inc.)

Table 1: comparison of 5,000,000 MWH annual production facilities

Note: Adapted from Solar Wind Energy Tower Inc. (Retrieved from https://www.solarwindenergytower.com/the-tower.html)

Conclusion and Recommendations

As the world is growing larger, every country should adapt to renewable energy sources. The revolutionary downdraft Solar Wind Energy Tower is better than only wind or only solar power plant. Downdraft Solar wind Energy plant is even better than the updraft solar wind plant. The downdraft solar wind tower construction is less expensive than the other renewable plant. The design of the plant consists of readily available components. The energy extraction source of the solar wind tower is water, wind, and solar, which is easily found everywhere. It has the capital cost less than solar or wind power plant.

I would highly suggest that the downdraft tower is the future of renewable energy source, and we should research it more to get all the benefits of that. I would also recommend that solar wind downdraft tower should be installed in a warmer area rather than colder area so it can generate electricity with maximum efficiency.

References:

1. Energy tower(downdraft) , Solar Wind Tower Energy Inc. Retrieved from: http://www.solarwindenergytower.com/the-tower.html
2. Petant US8120191B1, (J. Hanback,2012) Retrieved from: https://patents.google.com/patent/US8120191
3. Pump selection guiude, Goulds Pumps Retrieved from: https://gouldspumps.com/ittgp/medialibrary/goulds/website/Literature/Pump%20Selection%20Guide/Goulds_Rev_PSG.pdf?ext=.pdf
4. Automatic nozzle , Spraying system Co. Retrieved from: https://www.spray.com/spray_nozzles/automatic_nozzles.aspx

Appendix:

Definitions:

Mist:

Mist is a phenomenon caused by small droplets of water suspended in air.

(archieved.today,2012, retrieved from https://archive.is/20121210065921/http://www.rcn27.dial.pipex.com/cloudsrus/mistnfog.html)

Convection:

Convection is the heat transfer due to the bulk movement of molecules within fluids such as gases and liquids, including molten rock.

(Fundamentals of Heat and Mass Transfer (3rd ed.). John Wiley & Sons. p. 28. ,P. Frank, DeWitt, David P., 1990, Retrieved from https://en.wikipedia.org/wiki/Convection)

1. Figure: hydraulic to electric converters 110 (Petant US8120191B1, J. Hanback,2012)

Source: https://patents.google.com/patent/US8120191