Designing buildings for energy efficiency

[Naveed Yaseen]

ELECTRICITY generation and conservation both are equally necessary for tackling the current energy crisis. And one of the significant ways to conserve energy is to construct energy-efficient buildings.

These include, retrofits, smart designs, evaporative cooling units, radiant floors, high efficiency refrigeration and natural light arrangements. Building sector has a large share of the world’s total energy consumption.

According to the International Energy Agency (2005) 30-40 per cent of the worldwide energy is being used in construction activities. Up to 90 per cent of the energy is utilised during the operational stage for the purposes of heating, cooling, and lighting. Emissions related to buildings stem primarily from electricity and other energy sources used to light, cool, and heat our buildings.

Energy efficiency should be worked into a building’s design and not added later. Increasing energy demand, global climate change, and constrained energy supplies are likely to impact on businesses in future.

The ground-breaking report, Energy Strategy for the Road Ahead, reveals what 20 leading US companies recommend that businesses should now prepare for the energy risks.

According to the fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), building-related carbon dioxide emissions (including the use of electricity) could increase from 8.6 billion tonnes in 2004 to 11.4- 15.6 billion tonnes in 2030.

The demand for energy in the building sector is on increase, especially in rapidly growing economies of the developing countries. In terms of international averages, 60 per cent of residential energy is consumed for space heating or cooling depending upon climate zone.

General guidelines about construction need to be adjusted to the different climate, economic and social conditions. Integrated building design and the modification of building shapes, orientations and related attributes can also reduce energy demand and change energy-wasting operations.

In Pakistan, the overall life style and construction pattern is highly energy inefficient, without much of ventilation and require a lot of cooling arrangements . Energy conservation in buildings and alternate sources of energy at minimal possible cost offers multiple dividends in the ever-mounting energy crisis scenario.

Since the past two years, the situation has worsened. Although per-capita electricity consumption is around 500-kilowatt hours per year, which is one-fifth of the global average of 2,500-kilowatt hours, 6-18 hours of outages during summer 2009 have been daunting.

Buildings require continuous air conditioning because of rising temperature due to global warming.. The Building Energy Code of Pakistan’ developed by The National Energy Conservation Centre in 1990 is now undergoing a review by the ministry of environment.

It is expected that the implementation of energy codes would help control wastage and would save 20--30 per cent of the energy used in buildings. However, the building control instruments of various city development authorities, are eroded and ineffective, allowing numerous irregularities in construction designs and architecture.

NESPAK also revised the building codes for all major cities and made a master plan for major towns in the quake-hit areas that included housing, education and healthcare. Energy use in a building is a function of building services, the general design and the interaction of people living in the building. .

PEPCO has the responsibility to supply electricity to over 18 million consumers ,excluding Karachi. Total electricity consumption has touched 18000 MW in recent times due to increase in use of electrical appliances, particularly air conditioners requiring additional 3500 MW of electricity, which has widened the demand and supply gap.

Many modern technologies like, structural insulated panels, and concrete foundations, geothermal heat pumps, heat/energy recover ventilation systems, radiant floor heating can be used to construct energy efficient buildings.

Thermal barrier paint makes buildings energy-efficient, reduces energy costs, improves hot/cold insulation, certified CO2 emission reduction, fights global warming, is cost-effective, easy to understand and user-friendly. Solutions like thermal insulation, solar shading and proper ventilation must be promoted and made available to people. Minimum use of glass in buildings must be advocated and enforced by the regulatory agencies.

The performance, comfort and energy use of most buildings is influenced by the climatic conditions and the way a building responds to and develops the local micro-climate. Traditional building responses to particular climate types are explored, starting from the effectiveness of vernacular design as a climate modifier. The research on how building materials look, perform, last and interact with, and have impact on, the environment and the people who use and view the building, must be conducted.

Methods which provide essential springboard for the design, specification, maintenance and demolition of buildings, must be devised. Efforts which explore a range of issues that relate to materials and sustainability including embodied energy, performance, waste and health must be investigated. A specialised in-depth assessment of glazing materials, shading and solar protection devices be considered.. Tools for the design of complete glazing systems, calculation of thermal performance, energy rating and labeling be employed. Selection criteria in heating and cooling dominated climates be analysed.

Solar thermal and photovoltaic design methods should also be developed. The design of dwellings and public buildings such as schools, healthcare facilities or religious buildings that accommodate current requirements and respond to contextual, climatological and cultural factors, is undertaken in an experiential and interactive mode.

The concept of reconciling regional identity and tradition with contemporary needs in building design and performance, relating to the impact of technological change and social transformation arising from globalisation, climate change and other factors, have to be focused upon.

By using the green building designs and technologies up to 70 per cent electrical energy could be saved and meet 90 per cent air-conditioning demand. The government must enforce modified building laws to ensure energy efficiency through its regulatory bodies , particularly the city development authorities.

No NOC should be issued by the concerned departments to buildings which have a lower or no degree of energy efficiency.

Construction companies and the contractors must learn and master latest techniques of construction and usage of energy efficient technologies to change the construction pattern to ensure sustainable environmental management with less consumption of energy.

The writer is media manager, Pepco.

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