A review on solar energy use in industries

Abstract

Presently, solar energy conversion is widely used to generate heat and produce electricity. A comparative study on the world energy consumption released by International Energy Agency (IEA) shows that in 2050, solar array installations will supply around 45% of energy demand in the world. It was found that solar thermal is getting remarkable popularity in industrial applications. Solar thermal is an alternative to generate electricity, process chemicals or even space heating. It can be used in food, non-metallic, textile, building, chemical or even business related industries. On the other hand, solar electricity is wildly applied in telecommunication, agricultural, water desalination and building industry to operate lights, pumps, engines, fans, refrigerators and water heaters.

It is very important to apply solar energy for a wide variety of applications and provide energy solutions by modifying the energy proportion, improving energy stability, increasing energy sustainability, conversion reduction and hence enhance the system efficiency. The present work aimed to study the solar energy systems utilization in industrial applications and looked into the industrial applications which are more compatible to be integrated with solar energy systems.

Introduction

Energy use has become a crucial concern in the last decades because of rapid increase in energy demand. Moreover, environmental issues of conventional energy resources such as climate change and global warming are continuously forcing us for alternative sources of energy. According to the statistics released by World Health Organization (WHO), direct and indirect effects of climate change leads to the death of 160,000 people per year and the rate is estimated to be doubled by 2020. Climate change causes natural disasters such as floods, droughts, and remarkable changes in atmosphere temperature. Moreover, some diseases become epidemic among the societies mainly malaria, malnutrition and diarrhea. One of the disasters was reported in 2003 which attacked European countries and caused death of 20 thousand people while remained $10 billion losses in agricultural sector [1].

Currently, conventional energy sources constitute almost 80% of global energy consumption. The urgent need to substitute the energy sources was postponed aligned with discovering nuclear energy in the middle of 20th century, which would stand out for ten to twenty times more than fossil fuels. However, there are some limitations associated with nuclear source of energy. For instance nuclear fusion is exposed of uranium and thorium ores which are considered fossil fuels as well. In addition, nuclear plants are currently available only in large scale power generations. Therefore, for cooking, heating and small scale applications renewable energy is still the best choice. It is the source of energy that mankind can continue their survival on the earth without depending on fossil fuels [2]. Renewable energy sources like solar, wind, biomass, hydropower and tidal energy are promising CO₂ free alternatives [3], [4]. Despite the general awareness of advantages of renewable energy utilization, this source of energy contributed only about 1.5% of world energy demand in 2006. The trend is estimated to rise up to 1.8% in 2030. Table 1 shows global industrial energy consumption patterns for various sources of energy for the years 2006 and 2030.

The importance of energy in industrial development is very crucial since major fraction of energy is used in industrial processes. It has dominated more than 50% of total energy consumption worldwide. The delivered energy in industrial sector is utilized in 4 major sectors: construction, agriculture, mining and manufacturing. Industrial sector energy consumption, savings and emission analysis for electrical motors, compressed air, and boilers have been discussed in [6], [7], [8], [9], [10], [11], [12] and revealed that a major chunk of energy is used in this sector. Table 2 shows the industrial sector energy use for few selected countries around the world.

Fig. 1 shows the industrial energy consumption trend until 2030.

Due to rapid growth in conventional fuel prices and environmental constraints, enterprises are not attracted to use fossil fuels in industrial sector anymore. By applying renewable energy based systems in industries, the greenhouse emissions could be reduced significantly. Therefore, traditional energy supplies should be shifted to renewable sources of energy and new technologies has to be developed and applied in industries.

Among all the renewable energy sources, solar power attracted more attentions as a greatest promising option to be applied in industries. Solar energy is abundance, free and clean which does not make any noise or any kind of pollution to the environment. So far, many attempts have been made to extract solar energy by means of solar collectors, sun trackers and giant mirrors in order to utilize it for industrial purposes. Solar energy applications in industry are divided into 2 main categories: the solar thermal and the photovoltaic. Some of the most common applications are hot water, steam, drying and dehydration processes, preheating, concentration, pasteurization, sterilization, washing, cleaning, chemical reactions, industrial space heating, food, plastic, building, textile industry and even business concerns [1], [2].

Table 3 shows the share of different sources of renewable energy for industrial applications (excluding hydroelectric and biomass) in term of annual production and global demand for 2001.

Due to the global energy shortage and controlling harmful environmental impacts, application of solar energy has receiving much attention in the engineering sciences. Hence, intense search for effective and economic methods to capture, store and convert solar energy into useful energy should not be neglected [2]. In the literatures there is no comprehensive review on the applications of solar energy in industrial facilities. It is expected that this review will be very useful for industrial energy users, policy makers, research and development organizations, and environmental organizations.