Easy, by design

Published : Jun 01, 2007 00:00 IST

The ECBC is an effective tool to reduce energy use in buildings.

BUILDING design has not been a subject of study in India for its electrical and thermal performance. A building's configuration, aesthetics, first cost, uniqueness and ultimate saleability are some of the factors that have driven building design. The operating energy cost of a building increases tremendously if energy efficiency factors are ignored at the design stage.

To avoid waste of energy and to bridge the gap between power demand and supply, the Government of India enacted the Energy Conservation Act and established the Bureau of Energy Efficiency (BEE) under the Ministry of Power. One of the important provisions of the Act relates to the enforcement of the Energy Conservation Building Code (ECBC) for efficient use of energy and its conservation in buildings or building complexes.

The ECBC sets the minimum energy performance standards for buildings. The ECBC for commercial buildings is widely considered cost-effective as government-based regulatory programmes can potentially help effect substantial energy savings.

It is essential to design new buildings incorporating energy-efficiency features right from the initial stages. The application of the ECBC is necessary for this purpose. The intention of the ECBC is to benchmark energy consumption levels in large commercial buildings and introduce a level of awareness of energy conservation.

The ECBC has had a long and proven history of improving energy performance of buildings and yielding significant savings. The ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) standards in the United States, for example, have resulted in over 60 per cent reduction in energy use in typical buildings.

In developing countries, estimates of potential energy savings from first-generation building energy codes have typically ranged from 20 per cent to 35 per cent. These savings can be significant since commercial buildings often account for 25 per cent to 33 per cent of the country's electricity use.

According to the E.C. Act, energy conservation building code means the norms and standards of energy consumption expressed in terms of per square metre of the area where the energy is used and includes the location of the building.

Section 14 (p) of the Act empowers the Central government to prescribe the ECBC. The BEE has the responsibility under Section 13 (d) to take suitable steps to prescribe guidelines for the ECBC.

The E.C. Act mandates the ECBC for buildings with a connected load of 500 kw or a contract demand of 600 kVA and above, which are intended to be used for commercial purposes and constructed after the rules relating to the ECBC have been notified by the State governments under Section 15 (a).

The ECBC will also be applicable to additions, alterations and modifications to existing buildings. Its applicability to existing buildings is subject to several riders and exclusions, which are set out in the ECBC.

In the process of developing the ECBC, all stakeholders - architects, engineers and other design professionals, concerned government agencies, building-products manufacturers, developers and non-governmental organisations - are involved. The BEE has constituted a Committee of Experts (COE) and stakeholders that pilots an extensive consultation process spread over three years. Participation of these groups ensured that the requirements are appropriate for local design conditions and construction practices. The ECBC has been developed to cater to five different climatic zones in the country, as is the case with the national building code. These climatic regions are composite, hot and dry, warm and humid, moderate and cold.

Due care has been taken to ensure that the codes regulating energy use in buildings are simple. The code document will only specify performance requirement in an easy-to-use format.

The ECBC sets minimum energy efficiency standards for design and construction of non-residential buildings. Energy performance standards for the following building systems are included in the ECBC: building envelope; lighting; heating, ventilation and air-conditioning service; water heating and electric power and distribution.

The ECBC encourages energy-efficient design or retrofit of commercial buildings so that they are designed in a manner that reduces the use of energy without affecting the building function or the comfort, health and productivity of the occupants, and with appropriate regard for economic factors. The code eliminates design practices that lead to unnecessarily high use of energy and associated costs.

Besides reducing energy costs at large, compliance with the code improves comfort (both thermal and visual). The benefits to society include the following: reduced capital investments in energy supply infrastructure; reduced environmental impacts; improved electricity reliability; and more efficient use of resources. It is estimated that buildings that are ECBC compliant have a potential saving of about 30-35 per cent.

The ECBC expects building plans to include all pertinent data and features of the building, equipment and systems.

The following details are necessary: Building envelope: insulation materials, fenestration, solar heat gain coefficients, visible light transmittance and air leakage; overhangs and side fins, building envelope sealing details;

Heating, ventilation and air-conditioning: system and equipment types, sizes, efficiency levels, and controls; economisers; variable speed drives; piping insulation; duct sealing, insulation and location;

Service hot water and pumping: solar water heating system;

Lighting: lighting schedule showing the type, number and wattage of lamps and ballasts; automatic lighting shutoff; occupancy sensors and other lighting controls; lamp efficacy for exterior lamps;

Electrical power: electric schedule showing transformer losses, motor efficiencies and power factor correction devices; electricity check metering and monitoring system.

In India, estimates show that about 20 to 25 per cent of the total energy demand comes from industries manufacturing materials required in the construction sector and another 15 per cent from building owners and occupants. The ECBC sets a minimum efficiency standard for commercial buildings in all climate zones in the country. The estimated reduction in energy use for new buildings ranges between 25 per cent and 40 per cent, depending on the climate, building type and the hours of operation.

The average energy use for a typical commercial building is 200 kwh/square metre/year. Mandatory enforcement of the ECBC can reduce this to 120-160 kwh/sq m a year (a saving of 30-40 per cent).

In 2004-05, residential construction accounted for 19.25 million sq m and commercial construction for 21.5 million sq m. This was expected to increase by 10 per cent in the last year. Mandatory enforcement of the ECBC is expected to effect annual savings of 1.7 billion units in the first year of its implementation.

The ECBC has been prepared to ensure that the compliance processes are simple, clear and easy to use as much as possible; the proven techniques/best practices globally are adopted appropriately to suit India's conditions and objectives; all major stakeholders get incentives; the government takes necessary measures to ensure their proper dissemination and makes the ECBC compliance procedures consumer-friendly. It also commits itself to identifying appropriate methods of encouraging compliance.

Given the fact that the capacity required to effectively implement this code in the country is inadequate, its implementation will be on a voluntary basis initially. Incentives to promote its use in the voluntary phase will be provided along with promotion of the industry for insulators, windows, and so on.

Only when there is sufficient availability of both technical expertise and compliant material will the code be made mandatory. The government will launch an awareness campaign to promote the ECBC.

The ECBC is proved effective where it has been implemented with care. It is considered pivotal to any government policy on energy efficiency and climate change.

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