Sustainable Solar Power-The Solution to Providing Energy for Low Cost Housing

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SUSTAINABLE SOLAR POWER - THE SOLUTION TO PROVIDING ENERGY FOR LOW COST HOUSING? By Ghumaid Abdurahman, Intern, EES Africa (Pty) Ltd

South Africa faces an immense challenge to address the backlog in the construction and delivery of quality, low cost housing. While there are a number of initiatives underway, there is said to be a backlog of some 2.3 million houses. Integral to the construction of these houses is the provision of energy for basic needs. Solar technology is a cost-effective solution for providing energy to low cost houses.

ABOUT EES:

Established in 2001, EES Africa (Pty) Ltd specialises in the integration of multiple

system infrastructure including ICT, Data Centres, Audio Visual, Life Safety, Security

and Building Automation Systems. As an ISO 9001:2008 certifi ed company, our

vision is to be Africa’s management, engineering and auditing professional service

provider of choice. The EES Value Proposition focuses on translating technology into

tangible deliverables for clients through the experience of a talented team of Engi-

neering and ICT Consultants and Project Managers. With offi ces in Cape Town, Jo-

hannesburg and Stellenbosch, EES operates predominantly in the Financial Services,

Hospitality, Infrastructure, Mining, Oil & Gas, Renewable Energy, Retail, Telecoms

and Utilities sectors.

CONTENTS

Introduction

Page 2 Solar Panels

Page 2 Different Types of Solar Panels

Page 2 Which Panel is most Suitable?

Page 3 Power Storage

Page 3 The Solution for Commercial Housing (Low Power)

Page 3 References

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EES Cape Town offi ce:

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PO Box 31322, Tokai 7966Western Cape, South Africa

Email: [email protected]: +27 (0)21 702 8340Fax: +27 (0) 86 532 3532

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EES Stellenbosch offi ce:

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Introduction

South Africa faces an immense challenge to address the backlog in the construction and delivery of quality, low cost housing. While there are a number of initiatives underway, there is said to be a backlog of some 2.3 million houses.

Integral to the construction of these houses is the pro-vision of energy for basic needs. Solar technology is a cost-effective solution for providing energy to low cost houses. It enables the supply of electricity, vital for light-ing and hot water.

As solar technology is a type of renewable energy, it is green and sustainable. It is one of the most popular forms of renewable energy in South Africa, due to the country’s abundant sun. “Most areas in South Africa average more than 2 500 hours of sunshine per year, and average solar-radiation levels range between 4.5 and 6.5kWh/m2 in one day,” according to an statement from the Depart-ment of Energy. “The southern African region, and in fact the whole of Africa, has sunshine all year round. The annual 24-hour global solar radiation average is about 220 W/m2 for South Africa, compared with about 150 W/m2 for parts of the USA, and about 100 W/m2 for Eu-rope and the United Kingdom. This makes South Africa’s local resource one of the highest in the world.” [1]

There are many different factors and types of equipment involved in solar technology. Factors involved include:• how much electricity is needed, • what is to be run off the system, • how much is to be spent, • what space is available, and• is there the possibility of an upgrade at a later stage.

Due to these different factors, deciding which equip-ment ie. panel, battery, battery regulator and inverter, to use can be a challenge. An understanding of how solar technology works is fi rst needed. It is therefore best for potential users to familiarise themselves with the tech-nology or acquire a professional’s opinion before head-ing out to the stores. This paper examines the various options, and then provides a conclusion as to the best combination of equipment to choose.

Solar Panels

Solar panels remain the most popular type of solar re-newable energy at present because of their reliability and consistency. They produce electricity from photons, which is found in light radiation. This means even on overcast days they will produce some energy, although they will obviously produce more electricity with direct sunlight. There are many manufacturers of solar panels, who offer installation and maintenance as well. While the initial cost may be a little high, the long term benefi ts more than makes up for this. Another key advantage is that the use of solar panels helps reduce CO2 levels.

Different Types of Solar Panels

1. Solar Electric Solar electric works by means of Photovoltaic (PV) panels. The PV panels use semi-conductor technology to directly convert sunlight into

SUSTAINABLE SOLAR POWER - THE SOLUTION TO PROVIDING ENERGY FOR LOW COST HOUSING?

August 2014

electricity. The semi-conductors mostly comprise silicon, and other elements are added to it by a process known as doping. Silicon has special chemical properties ideal for solar cells. The PV panels only operate when the sun is shining, and must be coupled with other power generation mechanisms to ensure a constant supply of electricity.

2. Solar Thermal Solar heating uses panels or mirrors to concentrate and collect sunlight. The concentrated sunlight is then directly used as a source of heat, as in solar water heating. It allows excess thermal energy to be collected for later use.

3. Thin Film Nano Solar In 2005 Professor Vivian Alberts of the University of Johannesburg developed a solar panel known as Thin Film Nano Solar. These panels are more effi cient in terms of manufacturing and cost of production than silicon PV, as they do not use silicon. Instead they are based on Copper, Indium, Gallium, Selenium and Sulphide (CIGS), which do the same basic thing as the silicon in PV panels [2].

Which Panel is most Suitable?

Solar electric panels are ideal for producing energy which can be used for heating purposes. However solar electric panels do not directly store en-ergy. They simply convert sunlight into energy. The panels therefore need to be sourced and coupled to a battery for energy storage.

Solar panels are made up of arrays of solar cells, which come in differ-ent sizes. The solar panels absorb the sun’s energy and are responsible for converting that energy into electricity. Low power solar panels range from 0.5V to 15V.

There are different types of PV panels which can be used and each is suit-ed to a different type of application. The main types are Monocrystalline, Poloycrystalline and Thin Film. Their prices vary from each other. This is due either to their size or manufacturing process involved.

Different types of PV panels sold commercially:

1. Monocrystalline• An obvious defi ning characteristic of Monocrystalline is its dark black panels.• The physical nature of Monocrystalline is silicon. On average these panels are more effi cient than the rest. However it should be noted that solar technology is ever changing in both Monocrystalline and Poloy crystalline, and a great deal depends on the manufacturer. There are panels where Poloycrystalline panels achieve higher effi ciency than Monocrystalline, and again this can be attributed to the manufacturer.• Monocrystalline panels typically have an effi ciency of 15-20% (http://energyinformative.org/). For applications where availability of space is a limiting issue for achieving a desired output power, Monocrystalline would be superior as it has a higher effi ciency rating per square meter.• In terms of lifespan most manufacturers have a 25 year warranty on their products.• In terms of price Monocrystalline is the more expensive per KW than Polycrystalline, because it is manufactured with higher quality silicon.

2. Polycrystalline• An obvious defi ning characteristic of Polycrystalline is its blue refl ective panels.• Typical effi ciency for these panels range from 13-15%, because the silicon used to manufacture Polycrystalline is not as pure as that used for Monocrystalline.• The cost would also be cheaper since a less pure form of silicon is used in production of the panel.• Heat tolerance is lower than in Monocrystalline panels.

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SUSTAINABLE SOLAR POWER - THE SOLUTION TO PROVIDING ENERGY FOR LOW COST HOUSING?

August 2014

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Written by Ghumaid AbdurahmanIntern EES Africa (Pty) LtdTel +27 21 200 5939Email [email protected]

Ghumaid is currently studying a National Diploma in Electrical Engineering at the Cape Peninsula University of Technology.

3. Thin Film Solar Cells Thin Film solar cells are manufactured by placing one or several thin layers of photovoltaic material onto a substrate. They come in different photovoltaic materials, namely:• Amorphous silicon (typical effi ciency is about 6-8% when “stacked”)• Cadmium telluride (typical effi ciency is about 9 -11%)• Copper indium gallium selenide (typical effi ciency is about 10-12%)• Organic photovoltaic cells (these come in a wide variety and are typically between 5-10%)

Effi ciency varies depending on what type of Thin Film so-lar cell technology is used. It should be noted that these effi ciencies are always changing. Tremendous growth has been seen over the years in Thin Film solar panels and they are catching up to silicon PV panels.

Thin Film solar panels are however not suitable if there are space constraints, meaning that for the same surface area PV panels would be more effi cient.

Power Storage

Another important factor is power storage. The key here is the type of battery to be used.

• The type of battery to be selected depends on budget. A home owner does not necessarily need the best on the market if designing a PV system for a relatively small home. It is preferable for typical home owners to use a deep charge cycle battery, as this type of battery will often run below half of its designed potential.

• A battery charger or regulator is also needed. This regulates the battery or batteries charging voltage and current. If you do not install this the battery will simply keep charging and would consequently dam age battery. A solar battery charger can also improve battery charging quality which helps with maintaining the battery life.

• Last but not least is an inverter. The inverter converts the direct current (DC) power from the battery in a sinusoidal (curve in the form of a smooth repetitive oscillation), alternating current (AC) wave, so that it can be used to power electrical equipment in the home. For devices that use direct current such as some LED lighting and USB cell phone charging, an inverter is not necessarily required, but it is recommended as it produces a cleaner form of DC.

The Solution for Commercial Housing (Low Power)

If you are planning to install a PV system for lighting and cell phone charg-ing, and possibly other small applications, such as power for your router, a 30W solar panel will be suffi cient.

It would be more effective to use Monocrystalline or Polycrystalline panels as opposed to Thin Film solar cells. This is because the panel systems take up less space than Thin Film solar cells. The amount of power you want your panel to produce, your budget, and space availability would determine whether you choose Monocrystalline or Polycrystalline.

A deep cycle lead crystal battery would be the best choice if you will be using the battery often throughout the day, as this battery is designed for constant discharge and charging cycles. The battery rating would depend on the power you need. A 12V battery would suffi ce for low power appli-cations, and most low power solar products are designed for 12V.

A solar battery charger controller or regulator suitable for the deep cycle lead crystal battery is then required. It must display the level of the battery’s voltage and let the user know when the battery is fully charged.

Inverters, used for converting DV power into AC power or vice versa, utilise a great deal of power. Use of an inverter is only recommended if the user is planning to run AC appliances off the solar system, and in this case a 40W inverter would be suitable. It should be noted that inverters require power in order to convert between two power signals, which would drain the battery faster.

To conclude, the cost of the entire system should fall just under R1000 for all items. It would however be best to spend a bit more on the battery and battery regulator if you want to upgrade or expand your solar system in the future. Installation costs will of course vary depending on which organiza-tion you use, and it is therefore advisable to obtain a number of quotes before deciding on which contractor to appoint.

The result is a basic, cost-effective, green and sustainable solar system, which can be used even in remote locations.

References:

[1] http://www.energy.gov.za/fi les/esources/renewables/r_solar.html[2] http://www.solarpowerstore.co.za/articles/types-of-solar-panels.html

Sustainable Solar Power-The Solution to Providing Energy for Low Cost Housing

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