Solar Water Heating System Presented By: BHANU PRATAP CIVIL ENGINEERING 3rd Year
INTRODUCTION• India is blessed with solar energy in abundance at no cost.• India is having high solar insolation of 46.5 KWh/sq.m/day for an average of 280 sunny days and most of that resource has been left untapped.• One of the popular cost-effective devices that harness the solar energy is Solar Water Heating System (SWHS).• SWHS heating system is a commercially viable and technologically mature product, is existing in country for many years with enormous potential.
HISTORY• There are records of solar collectors in the United States dating back to before 1900, comprising a black-painted tank mounted on a roof.• SWHS has been widely used in Greece, Turkey, Israel, Australia, Japan, Austria and China.• Israel is a country, where solar water heaters are being used since 1950s.• There was a fuel crisis and restrictions were imposed on heating water using fossil fuel.• Since then the Israelis are accustomed with heating water using SWHS. In 1980, the Parliament of Israel introduced a law on mandatory solar heating for new residential buildings
Scope in India• India has a varying climate extending from extreme to moderate due to its unique geographical features.• Normally in the countryside, wood or biomass is used for heating and in urban areas electricity or fossil fuels are used for this purpose. This practice is either expensive or degrades the environment.• Therefore, solar water heating system can be a suitable alternative to meet the growing demand of hot water in the country without exerting further pressure on electricity or cutting of forest trees from the forest areas. The SWHS has the potential to save millions in energy costs in our country.
Steps Taken By Indian Government • Ministry of New and Renewable Energy (MNRE), government of India and some state-level agencies have formulated many schemes for promotion of SWHS. • There are also provisions of providing soft loans under the interest subsidy scheme through a network of financial institutions and tax benefits on all investments in solar energy technologies. • The Bureau of Energy Efficiency (BEE) as per provision of the Energy conservation Act 2001 has prescribed guidelines for Energy Conservation Buildings Code (ECBC), which sets minimum energy standards for design and construction of buildings. SWHS is one of the components covered under ECBC to enhance energy performance of the buildings. • With the objective of contributing to India’s Energy security and sustainable development, the Prime Minister has launched Jawaharlal Nehru National Solar Mission (JNNSM) in January 2010. The objective of the mission is to establish India as a global leader in solar energy.
Uses of Solar Water Heating System • Bathing. • Laundry application in hotels, hospitals, hostels. • Cooking (Pre-Heating of water helps in reduction of use of fuel). • Various industrial applications.
Contd., • A solar water heater consists of a collector to collect solar energy and an insulated storage tank to store hot water. The total system with solar collector, storage tank and pipelines is called solar hot water system. • The solar water heating systems are of two categories: 1) Closed loop system. 2) Open loop system.
Contd., • In the closed loop system, heat exchangers are installed to protect the system from hard water obtained from bore wells or freezing temperatures in the cold regions. The open loop system has two categories – 1) Thermosyphon. 2) Forced circulation system.
Contd., •Thermosyphon systems are simple and relatively inexpensive. •The forced circulation systems employ electrical pumps to circulate the water through collectors and storage tanks. •The choice of system depends on heat requirement weather conditions, heat transfer fluid quality, space availability, annual solar radiation etc.
Conclusion• There is a serious need to sensitize policy makers andusers in the residential and commercial sectors on theefficacy of SWHS.• There is a perception that SWHS is more suited forindependent houses rather than apartment buildings. Butthe later would ideally have more roof space for an idealand attractive SWHS.•The manufacturer and supplier base of the system hasto be strengthened, so that, they can also createawareness among potential users of SWHS.