By: Prof. Ts. Dr. Salman Yussof
For countries like Malaysia where it is hot and humid throughout the year with an average temperature of 27 degree Celsius, people rely heavily on indoor cooling and ventilation to ensure occupant’s comfort. And due to the hot climate, most people spend more than 90 percent of their time indoors.
Buildings typically consume a large amount of electricity energy to maintain its indoor temperature, ensure appropriate air circulation and providing interior brightness. On average, buildings worldwide consume about 40 percent of overall energy resources. These buildings also contribute to an average of 30 percent of global carbon emission. Dense building occupancy and poor management on the ventilation system are two major contributors towards indoor carbon dioxide (CO2) generation. Trapped CO2 increases indoor temperature, leading to higher energy consumption to maintain ideal indoor temperature level.
To improve building energy efficiency, the concept of green building has been introduced. In fact, green building is not just about energy efficiency. Green building refers to the design and construction of a building that ensure energy and water efficiency, as well as being environmentally responsible. A green building should be designed to use as much natural cooling and lighting as possible so that the use of electricity for cooling and lighting is minimized. Even the materials used for construction should be environmentally friendly and can be properly recycled if the building is to be demolished when it is no longer needed in the future.
Since green building must start from the planning and construction stage, it cannot be applied to legacy buildings. Legacy buildings refer to old buildings that were built more than 20 years ago that are still in use today. These buildings are usually still in good condition. Demolishing and rebuilding these buildings to incorporate green building features are not economically feasible and can be harmful to the environment. Some of these buildings also need to be maintained due to historical or sentimental values. On the other hand, these buildings are normally energy inefficient due to the use of centralized air-conditioning and extensive lighting.
Centralized air-conditioning means the whole building needs to be equally cooled regardless of room usage or occupancy. And due to the building design, most rooms and interiors require lights to be turned on even in the middle of the day. While new buildings with green technology or energy efficiency capabilities are on the rise in Malaysia, there is a need to see what could be done to integrate energy efficiency capabilities in legacy buildings. This is to ensure that the energy consumption for maintaining such buildings is optimized while at the same time ensuring comfortable living or working environment for the occupants.
One possible solution to improve the energy efficiency of legacy buildings is to perform building retrofit. Building retrofit refers to any kind of redesign or upgrades of an existing building that is partially or wholly occupied to optimize resource usage while maintaining or improving the comfort level of occupants.
Among the components that can be installed during building retrofit are energy-efficient lights, sensors for monitoring and measuring building environments, lighting control system, split air-conditioning systems, smart HVAC (heating, ventilation and air-conditioning) control system, smart plug and load control, and energy management system. Each of these components can contribute to the reduction of electricity usage.
Therefore, although it may not be possible to retrofit a building with all the components mentioned above; even installing a few of them may already help to improve the energy efficiency of the building. And even though the retrofit may incur some costs at the beginning, the improved energy efficiency would help to reduce the maintenance costs of the building in the long run.
The author is a Professor at the College of Computing and Informatics, Universiti Tenaga Nasional (UNITEN), and may be reached at firstname.lastname@example.org