The document discusses solar power satellites as a solution to dwindling non-renewable energy resources. It describes how solar power satellites would collect solar energy in space using more efficient methods than on Earth. The collected energy would be transmitted to Earth via microwave beams to large rectifying antennas. It provides details on the methodology, including the Brayton cycle for power generation and wireless power transfer simulations using MATLAB. Alternative cycles like Ericsson and Rankine are also mentioned.

1. Solar Power
Satellites
A RADICAL SOLUTION TO THE ENERGY CRISIS
RV College of Engineering
Department of Electronics and Communication
Presented by: R Jayanth

2. Objective
• The world’s non-renewable energy resources are being
consumed at an ever increasing rate.
• The population expansion has worsened the situation.
• Expected year of exhaustion of non-renewable resources:
• Uranium: 2042
• Oil: 2046
• Gas: 2049
• Coal: 2056
• Solar Power Satellites are a radical new solution to this problem.
• They are a means of tapping into the almost infinite energy
reserves of the sun in a more efficient way than can be done on
earth.
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3. Methodology
• Phase-I
• Introduction to Space Based Solar Power Systems (SBSP).
• Need for SBSP.
• Thermodynamic Cycles for Solar Power generation (Brayton Cycle).
• Reception of Solar Power on Earth by means of Rectifying Antennae.
• Calculation of Efficiency of Rectification.
• MATLAB graphs ofWireless PowerTransfer circuits.
• Phase-II
• Brief history of Solar Power Satellite (SPS)Technology.
• Various SPS models proposed.
• Mechanism of transmission of power through microwaves.
• Ericsson and Rankine Cycles as alternatives to Brayton Cycle for power
generation.
• Present and upcoming initiatives in SBSP technology.
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4. Introduction
• Space-based solar power (SBSP) is the concept of
collecting solar power in space (using an "SPS", that is, a "solar-
power satellite" or a "satellite power system") for use on Earth.
• SBSP differs from existing solar power technologies because the
means of collecting the power is in an orbiting satellite, and not
the Earth.
• The collecting satellite would convert solar energy into electrical
energy on board, powering a microwave transmitter or laser
emitter, and focus its beam toward a collector (rectenna) on
Earth's surface.
• Why SBSP?
• 55–60% of the Solar Energy is lost in the atmosphere on the way to
the earth’s surface due to the effects of reflection and absorption.
• Large downtime due to the earth’s rotation can be avoided.
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5. Simplified representation of a Solar Power Satellite
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6. Electronics
• A rectenna is a rectifying antenna, a special type of antenna
that is used to convert microwave energy into direct current
electricity.
• A simple rectenna element consists of a dipole antenna with
an RF diode connected across the dipole elements.
• The diode rectifies the AC current induced in the antenna by
the microwaves, to produce DC power, which powers a load
connected across the diode.
Rectifying Antenna
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7. Electronics
• The concept of a Rectenna was first introduced byWilliamC
Brown, a US Electrical Engineer working for Raytheon
Industries.
• Advantages:
• Unlimited lifetime
• Completely eco-friendly
Rectifying Antenna
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8. Hence η=
𝑽 𝟐
𝒐𝒖𝒕
𝑹𝒍𝒐𝒂𝒅
.
𝟏
Pd .Aeff
Mathematics
• Efficiency (η) is the ratio of the output power Pout to the input
power Pin
η =Pout / Pin
• Pin is w.r.t. the AC input, and depends on the power density Pd
across the receiver surface, as well as the effective area Aeff of
the receiver.
i.e. Pin =Pd .Aeff
Where Pd =
𝑃𝑡 𝐺𝑡
4𝜋𝑅2 andAeff=
𝜆2
𝐺 𝑟
4𝜋
• Pout is the dc output power.
Pout=
𝑉2
𝑜𝑢𝑡
𝑅𝑙𝑜𝑎𝑑
Efficiency of a Rectenna
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9. Mechanical Engineering
• The Brayton Cycle is a constant
pressure heat engine.
• The Closed Brayton Cycle is an
alternative to using photovoltaic
cells in SBSP systems.
• An inert gas is circulated through a
compressor and a turbine coupled
with a generator.
• The fluid is heated, expands through
the turbine, and is cooled by
radiating heat to space.
• A recuperator reuses the waste heat
from the turbine.
• Much more efficient than PV cells.
Closed Brayton Cycle
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10. Computer Science
• Simulation is a necessary stage in the
development of any new technology.
• MATLAB (matrix laboratory) is a multi-
paradigm numerical computing
environment and fourth-generation
programming language.
• It can be used to generate graphs and
models using input in the form of
programs.
Simulation of Wireless Power Transmission
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11. Computer Science
Simulation of Wireless Power Transmission
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12. Bibliography
[1] Rectennas for Wireless Energy Harvesting, Jingwei Zhang andYi Huang,
University of Liverpool
[2] A Historical Review of Brayton and Stirling Power Conversion
Technologies for Space Applications, Lee S. Mason and Jeffrey G. Schreiber ,
NASA GRC
[3] Brayton Cycle Conversion For Space Solar Power, Narayanan Komerath
and Brendan Dessanti,GeorgiaTech
[4] Design of aWireless PowerTransfer System using InductiveCoupling and
MATLAB programming, Somashekar B, David Livingston et al, Dr.T.
Thimmaiah Institute ofTechnology KGF.
[5] National Space SocietyArchives (http://www.nss.org/)
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