Solar desalination is one of the oldest and cheapest method for converting saline water into drinking water. It appears to be the best technique in solving the problem in relation to the shortage of drinking water. There were two techniques involved in desalination using solar energy. They were: (i) direct and (ii) indirect desalination. Direct desalination utilizes solar radiation and its capacity is comparatively low. While, the second approach is well suitable for larger capacities [1] .
The principle beyond solar desalination is similar to a hydrological cycle and as follow:
a. Direct solar radiation heats up the top surface layer of water
b. Evaporation of water,
c. Trapping of water vapor in the clouds and,
d. Condensation of vapor.
1.1. Basin type solar still
The basin type solar still was commonly used for distillation process, and the productivity is comparatively lower than other methods [2]. Shadow of side walls on the water surface during the morning and evening hours reduce the productivity of fresh water which has been discussed by various researchers. The use of internal and external reflectors in the solar still improved the hourly fresh water production rate. But on the economic aspect this increases the cost of distilled water and initial capital cost.
1.1.1.1. Inverted absorber
The radiation absorbed by the absorber convected to the absorber plate where the water is placed. The rest of radiations are lost to the atmosphere and glass covers. Sangeetha and G.N.Tiwari [4] investigated the performance of solar still and arrived to a conclusion that there is an increase in temperature of water in the absorber due to the reduction of heat loss from absorber and increased value of absorptivity. The output of solar st...
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...omestic purpose. The same has been experimentally investigated and validated by aybar et al [16]
Anburaj et al [17] experimentally investigated a inclined solar still with ridges inside the solar still. The rectangular ridges decrease the flow rate inside the still. Utilizing various wicks the system performance was found to be maximum for black cotton cloth of 4.2 L/day and at an optimum inclination of 30o.
1.2.1. Wick type solar still
Sodha et al [18] has experimentally investigated the effect of having wicks in a simple solar still for fresh water production. It has been concluded that the effect of having wicks in the solar still improved the production rate by 25% by capillary effect than the conventional solar still. Also the shadow effect of the side walls was reduced by deepening the basin to keep the wicks on the surface for better evaporation of water.
Perth has two seawater desalination plants, one is completed in 2006 with a 123,000 m3/d (45 GL/yr) water production powered by a wind farm. The other one is almost double size of first one, which is 100 GL/yr powered by 65 MWe of dedicated renewable energy, which together provide half the city’s needs.
Preview: Today I will discuss the potential that solar power has to become this country’s main supply of energy and the latest research that can make solar power more efficient and cost effective. I will also present the environmental benefits that come with using solar power over other and more harmful forms of energy.
The prime advantage of this approach to harnessing solar energy is that the process is simplified by combining energy gathering and storage into a single step. This process is robust, stable and cheap. One limitation of this process is, while this is useful for heating applications, production of electricity would require another step using thermoelectric devices or producing steam to run a generator.
...dient energy is a most promising energy source for generation of electricity with the high potential available in comparison to another source of renewable energy. There are many places in the world where the salinity gradient energy is available, so installation of the plants in rivers mouth can be produced and support the huge amount of global electricity demands in future. This essay study presented the over review for salinity gradient energy and discussed about the important techniques (i.e. RED and PRO) for harnessing energy from this type of renewable energy source.
Desalination is the process of removing salts from seawater or brackish water to produce freshwater (Norling, 2004). Advantages of desalination plants include providing drinking water to areas with no natural supply of fresh water, supplying fresh water during drought seasons, increasing drinking water to accommodate for the increased population growth, and the reduction of waterborne disease and sanitation mortality (Norling, 2004). However, the implementation of a water desalination plant costs an estimated $15 billion USD (Norling, 2004). Therefore, desalination plants are not a suitable solution since the areas that would most benefit from these plants are low-income countries. Additionally, little research and development has been invested into improving this technology (Norling,
According to a report on “environmental regulation” in remote areas, conventional desalination processes cannot be applied, due to insufficient infrastructure and energy supply. We can use Reverse Osmosis
The average human can not live any longer than three days without water. Many of the world’s fresh water sources are running dry or are being contaminated, particularly in developing nations, leaving many without safe water to drink. Only two and a half percent of the Earth’s water is freshwater, and less than one percent is accessible by humans (not tied up in ice caps). This one percent of the Earth’s water supply is expected to sustain a population of over 7 billion people, each needing 2.6 liters a day to remain fully healthy, plus all of the water required for agriculture and industry. These scenarios will only become more and more prevalent as time moves on and we consume more water. The United Nations has classified our planet as being in the midst of a global “water crisis.” Global water supply and shortages are becoming an incredibly real and serious issue, and planning for the future is key to preventing population decline due to a lack of safe drinking water. Shortages of drinking water lead to wars and serious international conflict for basic human survival needs. One of the most popularly and commonly proposed solutions to this problem is to create seawater desalination plants to remove salt from ocean water to make it safe to drink. These water desalination plants, however, are not a viable option to carry us in to the future due to their potentially harmful impacts and expenses.
Solar thermal energy is not the best way to heat your home and hot water because it is a very inefficient system. For example Martin Holladay from Green Building Advisor suggests that solar thermal energy is inconsistent. During the long days of summer more hot water is produced than what is needed. But during the dark, cold winter there is not enough hot water (parag. 6-9). This demonstrates that this method of heating is inconsistent and unreliable. During the winter when you need the heat the most, you will not have it. Plus in the summer, when hot water is not needed as much, hot water is produced in large amounts but there is no way to store it for a long time period which makes the system inefficient. As Michael Wolfe states “Devices cannot generat...
Solar cookers represent an eco-friendly form of cooking, and they signify one of the most fundamental methods of harnessing solar energy for human use. In the southern African region, solar cookers have gradually grown in popularity over the last few decades, as they represent an efficient solution to many of the economic and fuel-related problems facing rural communities. Free solar energy can be harnessed and used as a fuel to operate solar cooking apparatuses, thereby reducing the need for other fuels such as paraffin and wood (see Tucker, 1999). These cookers play a vital role in the lives of the many families who make use of them, as they are cheap and simple to operate. They provide the users with an effective and reliable method by which to cook their meals and play a huge role in terms of money-savings for these families.
In India Solar distillation is very useful in rural area where fresh water is not easily
One of the most compelling arguments for the use of renewable energy is how many forms exist of it. Nuclear power, solar power, wind power, tidal power, hydroelectric power, pumped storage, wave power, geothermal power, biomass, and biogas are the most widely known renewable energy sources (Darvill, 2013). This large selection of fuels supports the idea of renewable fuels one day powering the entire planet. All the sources of energy have different niches and benefits. Solar energy is extremely ef...
Water use in power-generating plants is usually expressed in two components: withdrawal and consumption. Withdrawal refers to taking away water from local sources for use in a power factory. Depending on the systems used in the plant, the withdrawn water may be returned to its source and made available for use in other areas; however, in some cases, the water cannot be recycled. Consumption refers to the water removed from its source for use in a power plant, which cannot be recycled, as it is lost through evaporation (Martin 21).
This is done by reflecting and amplifying the solar power to heat up the liquid generally water. As water has a very high boiling point at eats up a huge amount of thermal energy. That thermal energy is than used to rotate a turbine to generate electricity. Producing electricity by the mean of this technology will be cheaper and very eco-friendly. Although that technology is still under development theoretically this will have no carbon emission at all and will be safer than conventional technics that are being used. The figure below illustrates how it
I am certain that all have heard of the terms green house gases, fossil fuels, and global warming. Have you ever questioned what will happen if nothing is done about the environmental problems facing the world today? What if I answer you that, we can merely use the power from the sun to power up our entire planet without the use of harmful energy sources, which affect our atmosphere? The power from the sun is what we call solar power. Solar power is the energy that comes from the sun as light and heat energy, and then it is later converted into electrical energy through solar panels (Nelson, 2008). This kind of power is completely free, right? Why should we put a lot of expense on other sources of energy, when there is a complete free and healthy power? It is evident that solar energy is a healthy source of energy, which will help stop global warming all together, but it is economically efficient to switch everything to solar energy. Solar energy is capable of becoming the world's future power supply because, it is renewable, eco-friendly, and extremely efficient when strategically placed.
Hot Water Heaters: The easiest way to exploit solar radiation is as thermal energy. One way to harness this solar energy is to heat water. Aro...