Solar Photovoltaic

PHOTOVOLTAICS (POWER GENERATION)

The various forms of Energy are vital to the progress of mankind and industrialization can hardly be achieved without dependence on it. Because of the rapid exhaustion of fossil fuel reserves that provide the major sources of energy, scientists have started thinking about the research and development of non-conventional energy sources. A major achievement in this direction is the Photovoltaic (PV) technology that uses solar cells to generate electrical energy directly from sunlight.

Benefits of Photovoltaic technology:

Photovoltaic technology provides some major benefits some of which are listed below.

• Lower recurring costs. The recurring maintenance costs involved in the usage of solar energy are very low as compared to conventional energy systems as Solar Energy, by nature, comes free of cost.

• No pollution. Solar Energy is pollution-free and is therefore a vital contributor towards Quality maintenance and an important aspect of Environment Management System (EMS).

• Renewable in nature. Solar energy is renewable in nature and is not subject to depletion or exhaustion like petrol, diesel, fuel wood and other conventional fuels

• Longer life. Solar energy driven systems have longer life than others.

• Higher reliability. Among all electricity generation technologies, solar systems can provide reliable power for a larger number of applications.

• Operation is modular. Modularity is an advantage of solar systems and it allows the user to start with small systems for single applications initially and add on to their systems as their needs and funds increase.

• Credit gains for reduced carbon emissions, now available in many countries

• Possibility of application in remote areas where electricity has not yet reached. Solar energy can provide reliable power for a large number of applications across a wide variety of environmental conditions and geographical locations, in many of which areas previously it could even not be dreamt of.

• Combined Heat & Power (CHP). Solar systems provide cost savings through co-generation of Power and Heat

Solar power stations run 24 hours a day with alternative fuels (biomass, gas or oil) during non day-light hours thus extending their economic viability. On-site plants allow industry and commerce to respond to increased power demands as well as to reduce the dependence on centralized power supplies.

DESIGNING OF PHOTOVOLTAIC SYSTEM

Photovoltaic systems generally consist of a power source (the PV array), storage unit (usually a battery), charge controllers unit (voltage regulator, meters, alarms) and a load (device consuming the electric power). The steps that are involved in designing a photovoltaic system are the following:

• Calculating the Load

• Calculating the Module output

• Calculating the losses

• Choosing a Controller

• Sizing the storage capacity

• Matching Array size to load

 

APPLICATIONS OF PHOTOVOLTAIC SYSTEMS

Photovoltaic systems have found application in numerous areas where the remoteness of the sites precludes conventional forms of power from being used. Photovoltaic systems have been used for the following applications:

• Decentralized Power Generation

• Industrial Lighting

• Street Lighting

• Rural electrification and Water Pumping Systems

• Electric Shock Fencing

• Rural Telephone Exchanges

• Unmanned Offshore Oil Platforms

• Meteorological Data Collection Platforms

• Railway Distant Signalling Systems

• Railway Communication Equipment

• Railway Station Panel Interlocking Systems

• Railway Track Circuit Systems

• Microwave Repeater Stations

• Battery Charging Systems

• Desalination plants

• Navigation aids

• Portable Remote Communication Systems

• Cathodic Protection of Pipelines

• Lower Wattage Modules for powering low power applications.

• Standby power to institutions that cannot tolerate power stoppages

 

THERMAL (HEATING & COOLING)

Fossil fuels are being fast depleted and the burning of these fuels in an ever increasing rate is resulting in global warming with threatening consequences. On the contrary, sustainable development of the world demands progressively lesser dependence of the human society on these fossil fuels. Against the backdrop of increased demand for energy, the use of lesser amount of fossil fuels and increased supply of energy can only be met by a planned harnessing of non-conventional and renewable energy sources. The non-conventional energy sources are essentially of solar origin and solar thermal energy is an important component of it.

 

 

In every process industry control of temperature and heat flow rate are of critical importance. It is likely to be more so in food processing industries because of the quality of the product just by the consistency, by the taste and aroma is quite sensitive not only to the temperature but also to the uniformity of the same.

Benefits of Solar Thermal Systems:

Thermal energy provides the following major benefits:

• Lower maintenance costs. As already discussed, the maintenance costs of solar energy systems are very low as compared to conventional energy systems as Solar Energy is free in nature.

• Renewable in nature. Solar energy is renewable and is not likely to be depleted or exhausted like petrol, diesel and other conventional fuels

• No pollution. Clean Development Mechanism (CDM) benefit can be achieved by the user.

• Longer life. Solar energy driven systems have longer life than others.

• Higher reliability. Among all heat generation technologies, solar systems can provide reliable heat for a larger number of applications.

• Possibility of application in remote areas. Solar energy can provide reliable heat for a large number of applications across a wide variety of environmental conditions and geographical locations, in many of which areas previously it could even not be dreamt of.

• Combined Heat & Power (CHP). Solar systems provide cost savings through co-generation of Power and Heat

 

APPLICATIONS OF SOLAR THERMAL ENERGY

Solar thermal applications may be for Low temperature, Medium temperature or High temperature in some specific areas as listed below.

• Low temperature usage in:

 

• Swimming Pools

• Hatchery Ponds

• Ventilation Preheat

• Car Wash

• Snow Melting

• Mid temperature usage in:

 

•  Residential and Commercial Hot Water

•  Cafeterias

•  Laundries

•  Space Heating (Radiant Slab)

•  Prisons

•  Recreational Facilities

•  Day Care

• High temperature usage in:

• Industrial Processes

• Electricity Generation

• Often Used for Water and Space Heating

 

The following are some of the appliances using Solar Thermal energy that can be installed in homes, industrial and commercial organisations.

1. Solar water heaters

Solar Water Heating is a cost effective and environmentally cleaner alternative to diesel, gas and oil. The following are some industrial applications of solar water heaters:

• Hotels: Bathing, kitchen, washing, laundry applications

• Dairies: Ghee  production, cleaning and sterilizing

• Textiles: Bleaching, boiling, printing, dyeing, curing, ageing and finishing

• Breweries & Distilleries: Bottle washing, boiler feed heating

• Chemical /Bulk drugs units: Fermentation of mixes, boiler feed applications

• Electroplating/galvanizing units: Heating of plating baths, cleaning, degreasing applications

• Pulp and paper industries: Boiler feed applications, soaking of pulp.

 

2. Solar Cooker

Solar cooker saves fossil fuels, fuel wood and electrical energy to a large extent but can only supplement the cooking fuel, and not replace it totally. It is a simple cooking unit, ideal for domestic cooking during most part of the year.  A family size box-type solar cooker is sufficient for cooking for 4 to 5 members and can save upto 4 LPG cylinders every year. It has a life of about 15 years. Parabolic concentrating solar cookers are another option. It is designed to direct the solar heat to a secondary reflector inside the kitchen, which focuses the heat to the bottom of a cooking pot. It is possible to fry, bake and roast food. This system generates enough steam to cook two meals for 500 people.

 

3. Solar Air Conditioners

Solar energy can be effectively used for air conditioning using a variety of collectors combined with power blocks and thermal chillers. Solar powered absorption chillers can now be integrated into complete heating ventilation and cooling (HVAC) systems. This technology reduces electric power peak-load demand for air conditioning during the hottest times of the day. Following are some types of Solar air conditioners:

• Cogeneration and Parabolic Troughs - Parabolic-trough solar collectors combined with a distributed power plant can power air conditioning. Small power plants usually 100kW to 1MW and from 1MW to 10 MW in capacity can be operated on or off the grid. They are suited to commercial and industrial uses in office buildings, small communities, hotels, hospitals and industry.

• Vacuum Collectors and Double effect absorption Chillers - This type of collector can work well in areas of low diffused radiation - even in conditions of snow. It can reach temperatures of up to 250°C in certain configurations.

• A Flat Plate Solar Collector with Single Effect Absorption Chiller – This technology may be economically viable in certain locations depending on the costs of fuels, radiation levels and equipment costs.

• Flat Plate Solar Collector Combined with a Dessicant Chiller – It provides air-conditioning and dehumidification.

 

4. District Heating

Heating suitable for large residential complexes at temperature ranges of 80°C

5. Solar Process Heating Systems

These are designed to deliver high temperatures to a diverse range of industries. The system includes solar collectors, pumps, heat exchangers and storage tanks. Temperatures required for process heat are usually within 85 - 120°C depending on the industry. It can be used in the following industries:

• Food and dairy product processing: for sterilization, pasteurization and cooking

• Textile and wool: for bleaching washing and dying

• Paper Industry: for bleaching drying and paper pulp production

• Wine and beverages: for bottle washing and cooling

• Automotive industry: paint drying and degreasing

• Meat preparation: washing, sterilization and cleaning

 

Solar Energy Systems provide effective solution anywhere and everywhere as the sun’s rays come free of cost. They can be successfully installed on snow-clad mountains, on scorching desert sands, in the middle of thick jungles, on stormy seas, in dairies, on fields, in remote villages, in bustling cities, in educational institutions, commercial organizations and office buildings.

Solar energy makes excellent business sense. It reduces fuel costs and increases energy independence and stability. Solar power dramatically reduces carbon and other emissions that lead to pollution and global warming which increase health costs. The technology is proven and commercially viable.

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The main difference between rooftop and ground-mounted solar photovoltaic (PV) systems is where they are installed: 

• Rooftop: Installed on the roof of a home, usually at a higher elevation than ground-mounted systems. 

• Ground-mounted: Installed on the ground using a foundation, pipes, poles, or tubing. 

Here are some other differences between rooftop and ground-mounted solar PV systems:

• Space

  Ground-mounted systems require more space on a property than rooftop systems. 

• Cost

  Rooftop systems are generally less expensive than ground-mounted systems because they don't require additional space. However, ground-mounted systems can be more economical in the long run if a rooftop is unsuitable due to space or structural limitations. 

• Maintenance

  Ground-mounted systems are easier to service than rooftop systems. 

• Efficiency

  Ground-mounted systems can be more productive than rooftop systems because they can be oriented and tilted to maximize sunlight capture. 

• Installation

  Ground-mounted systems are easier to install and repair than rooftop systems. 

• Energy needs

  Ground-mounted systems are a good option for households with high electricity needs.