Solar as Alternative Energy

Welcome to this Alternative energy web site!

SOLAR ENERGY

·         Solar energy is the cleanest and most inexhaustible of all known energy sources.

·         Solar energy is a renewable resource that is available almost everywhere on earth.

·         Solar radiation is a general term for the electromagnetic radiation emitted by the sun.

·         Solar energy contains huge amounts of energy and is responsible for all natural processes on earth.

·         On average the solar radiation that enters earth’s atmosphere is 1367 Watts/m².

·         Solar energy can be classified into two categories, THERMAL AND LIGHT.

·         Solar radiation can be captured and converted into useful forms of             energy, such as heat (thermal energy) and electricity (light energy), using a variety of technologies.

·         Thermal energy (heat) obtained from the sun can be used for a number of applications including producing hot water, heating buildings and under-floor heating.

·         With water heating accounting for about 30% to 50% of an electrical bill, substantial saving can be made by installing a solar hot water heating system with significant environmental benefits.



·         Light energy can be converted into electricity by means of Photo-Voltalic cells (P.V. panels)

·         By using VACUUM TUBES the efficiency of converting solar radiation into heat is 70%.

·         The efficiency of converting solar radiation into electricity by using PV panels is 10% to15%.

   GLOBAL WARMING --- ECONOMIC IMPACT

·         Global warming is the increase in the average temperature of the Earth’s near-surface air.

·         The increase in globally averaged temperatures is mainly due to the increase in greenhouse gas concentrations in the atmosphere.

·         The major greenhouse gases on Earth are water vapour, carbon dioxide (CO₂), methane gas and ozone.

·         Fossil fuel (coal, oil & natural gas) burning has produced about three quarters of the increase in carbon dioxide (CO₂) from human activity over the past 20 years (Power Stations)

·         Eskom currently generates 44 000 MW electricity per day

                                    Coal                                        33 938 MW

                                    Mothballed coal                    3 720 MW

                                    Nuclear                                  1 930 MW

                                    Hydro                                          600 MW

                                    Pumped storage hydro       1 400 MW

                                    Gas                                         2 409 MW

                                    Wind                                             3.2 MW



                        New Projects

                                    Coal                                          9 600 MW (two stations)

                                    Pumped storage hydro       1 330 MW

                                    Wind                                            100 MW

·         Power Station costs expected to rise by 40 to 60% if measures are implemented to capture and store carbon dioxide emissions.

·         World economy to spend 1% of GDP to counteract the devastating effect of climate change. (Sir Nicolas Stern – The economics of Climate Change).

·         The South African government has set a target for renewable energy to contribute 10 000 Giga watt hour of total electricity consumption by 2013. Solar water heating can contribute 23% of this target.

·         The use of solar energy can help to combat carbon dioxide (C0₂) emissions.

·         Environmental benefits of solar water heating:

-       A 200 litre solar system can replace 8.85 kWh electrical energy per day at average solar radiation.

-       By replacing 8.85 kWh per day with renewable solar energy the following savings of emissions and resources will result.


ENERGY FUTURE



·         The world currently relies heavily on coal, oil and gas for its energy

·         Fossil fuels are non renewable and only finite resources are available that will eventually dwindle, becoming too expensive or too environmentally damaging to retrieve.

·         Energy from fossil fuels contributes significantly to the problems we face today with greenhouse gasses, air pollution, water and soil contamination and global warming.

·         Vast amounts of money are spent to find renewable sources of energy.

·         Solar energy is one of the cheapest alternatives for renewable energy resources and is available everywhere one earth.

ENERGY FROM THE SUN CAN BE USED FOR DIFFERENT HEATING APPLICATIONS INCLUDING HOT WATER, SPACE HEATING, UNDER FLOOR HEATING AND EVEN COOLING

NEW VACUME TUBE TECHNOLOGY

EVACUATED TUBE

·         Vacuum tubes are the absorbers of the solar energy and convert it into heat.

·         Vacuum tubes consist of two glass tubes (borosilicate glass) which are fused together at one end.

·         The inner tube is coated with a selective coating (Al-N/Al) that absorbs solar radiation efficiently but inhibits reflection heat loss.

·         The outer tube is transparent allowing light rays to pass through with minimal reflection.

·         The air is withdrawn from the space between the two glass tubes at a high temperature to form a vacuum, which greatly eliminates conductive and convective heat loss.

·         These tubes perform very well even in overcast and low temperature conditions.

·         In order to maintain the vacuum between the two glass layers, a barium getter is used.

·         During manufacturing of the tubes the getter is exposed to high temperature which causes the bottom of the tube to be coated with a pure layer of barium.

·         This silver layer provides a clear visual indicator of the vacuum status.

·         If the vacuum is lost, the silver layer of barium will turn white.

Vacuum tubes passively track the sun