The use of solar energy is rising at a rate of 20 percent every year in the past 15 years owing to the fast-falling prices coupled with efficiency gains. First world countries such as the United States, Germany, and Japan are the prime markets for solar energy and India has already joined the list. Besides, tax incentives have made it possible for solar electricity to be a cheaper alternative to conventional sources of energy.
Capturing solar energy can be accomplished in two ways- passive and active. You can capture solar energy passively by placing huge windows on the southern side of a building for heating the walls and floor. Those surfaces release the trapped heat at night and keep the place warm. On the other hand, the use of photovoltaics for the direct conversion of solar energy into electricity is an instance of active solar energy capture.
Passive solar heating
The site, climate and raw materials used in the building play a critical role in making passive solar heating successful. With the aid of energy effective strategies, the passive solar panels are able to reduce the heating and cooling loads of a building partially or totally with solar energy.
Next to lighting, heating or cooling forms the second dominant energy load for both domestic and commercial buildings. This is where the use of passive heating techniques can be brought in as it uses the sun’s energy for meeting the heating demands in the spaces as a means of renewal energy.
It requires consideration of several aspects such as total area, properties of the building and glazing orientation. In our country, almost all angles can be suitable though experts prefer southern orientation along with the use of carefully chosen glass cover. This is because it is much easier to shade these places with blinds or overhangs during high heat. Passive solar systems should be carefully devised for reducing glare and overheating.
Understanding the photovoltaic system
Many people are already aware of the photovoltaic cells that are easily found in calculators or the solar panels in rooftops and satellites. These cells are prepared from semiconducting materials such as computer chips. These cells, commonly called PV cells are used in the conversion of solar radiation directly into electricity. The solar cells are the primary constituent of the PV systems. Solar energy developed from PV cells is one of the most successful means of procuring energy as it reduces costs to a great extent.
PV cells comprise two or more layers of semiconducting elements like silicon. When it is exposed to sunlight, it generates electric charges as sunlight releases electrons from the atom of silicon. When these negative charge carrying electron traverse towards the cell, it causes an imbalance of charges between the front and back surface of the cell. This creates a voltage potential which is similar to the positive and negative terminals of the battery. The electrical output released from one cell is very small and therefore, numerous cells are placed together and encapsulated behind glass for forming a module or a panel. You can connect as many modules as required for forming the right electrical output.
This arrangement can be installed at a fixed angle on the roof or can be mounted on a tracking device that can follow the movement of the sun so that the maximum amount of sunlight can be trapped through the course of the day. The performance of PV cells depends on a number of factors such as building integration, specification, availability of sunlight and weather conditions. Though the sun produces huge amounts of energy in a wide spectrum, yet only a portion of it can be captured for conversion into electricity. But you can expect the efficiency of solar cells to increase in the days to come.
Hot water along with solar thermal energy for heating
Solar thermal energy is a great source of renewable energy which is used for producing hot liquid. If a vehicle is parked in the sun on a hot day in summer, heat builds up inside it. The working mechanism of solar thermal energy is somewhat similar and the generated heat is utilized in heating water or empty spaces. It reduces the emission of carbon dioxide and thus contributes to protecting the environment. There are several types of solar thermal collectors used for producing hot air or water while there is a considerable improvement in conduction, collection, absorption, storage and transfer of heat.
In solar water heating, a highly conductive panel containing fluid or water is heated with solar energy. This heat is transferred into a hot water tank and can be used to satiate the heating requirements of a domestic or commercial building. One of the best ways to make the most of your solar energy is by combining solar electricity through PV cells along with the thermal systems.
Using daylight for renewing energy
The biggest energy load comes from lighting in commercial buildings today and all over the world, the lighting solution is required even when daylight is available. Daylighting is a process of replacing or supplementing electric lights for providing illumination through sunlight. As the demand for energy is very high and there is a wide availability of sunlight in the daytime, it is one of the most impactful areas through which renewable energy can be created.
Daylighting autonomy is a means of creating lighting spaces naturally without electrical intervention. It involves a number of techniques such as efficient placement of windows, use of special painting coats for reducing reflection, changing the transmittance of the window depending on the weather and most importantly, using fiber optics and daylight collector for transmitting sunlight inside the building.
For the maximum level of benefits, aligning the highest load of cooling and the highest production of electricity is very important. The lighting load is reduced by adopting daylighting and therefore, it reduces energy consumption. Extensive research has been conducted worldwide for the generation of hybrid solar lighting using daylight with electric lighting. With this approach, there can be constant illumination at a much-reduced cost compared to traditional electric lights.