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Solar Cells theory

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Solar Cells theory
SOLAR CELLS

Chapter 1. Introduction to solar electricity

Chapter 1.

INTRODUCTION TO
PHOTOVOLTAIC SOLAR ENERGY
Miro Zeman
Delft University of Technology

1.1

Introduction to energy consumption and production

Any change that takes place in the universe is accompanied by a change in a quantity that we name energy. We do not know what energy exactly is, we use this term to describe a capacity of a physical or biological system for movement or change. Energy comes in many forms, such as electrical energy, chemical energy, or mechanical energy, and it can be used to realize many forms of change, such as movement, heating, or chemical change. Any activity, and human activity as well, requires energy. Human beings need it to move their bodies, to cook, to heat and light houses, or to drive vehicles. Human being is a greedy consumer of energy. An active young man needs about 2500 kcal (2.9 kWh) per day to fulfil his daily energy requirements. This means the energy of about 1060 kWh per year. The present global energy consumption is around 19 000 kWh per inhabitant per year. It means that on average a man consumes about 19 times more energy than is needed for his survival and satisfactory health. The mankind has witnessed an enormous increase in energy consumption during last
100 years. While in 1890 the energy use per inhabitant per year was around 5800 kWh it reached 20200 kWh in 1970. Since 1970 the energy use has dropped to the present level of
19000 kWh per inhabitant per year. The increase in energy use in the 20th century can be
- 1.1 -

SOLAR CELLS

Chapter 1. Introduction to solar electricity

related to an evolution process that has started about five centuries ago. The underlying motivation of this process was formulated during the Enlightenment period in the 18th century as the philosophy of human progress. The aim of the process was an examination of the surrounding world and its adaptation to the needs of people

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