Nur Haziqah Mohamad Zaidi’s research while affiliated with National University of Malaysia and other places

Building energy consumption in Malaysia has increased by 31% over the past 10 years, primarily driven by the high demand for air conditioning in response to the country’s hot and humid climate. An effective way to address this problem is to increase building energy efficiency with the aid of thermal insulation. This paper presents a techno-economic analysis of roof assembly retrofits for commercial and residential buildings in Malaysia. Various roof configurations incorporating insulation materials such as radiant barriers, reflective insulation, mineral glass wool, and stone wool are investigated. The first section of this paper details the use of Sefaira building energy simulation software to evaluate the annual reduction in cooling energy consumption achieved by various roof configurations for commercial and residential buildings. Subsequently, an economic analysis is conducted by calculating the internal rate of return (IRR) and payback period for investment in each type of roof configuration. The findings show that roof assembly retrofits can reduce annual cooling energy consumption in commercial buildings by 8.65% to 16.25% and in residential buildings by 11.1% to 13.8%. Additionally, the total annual energy consumption decreases by 4.70% to 8.83% for commercial buildings, such as hypermarkets, and by 4.10% to 6.10% for residential buildings, depending on the insulation system applied. The economic analysis shows that the roof assembly insulated with a radiant barrier and thick enclosed air gap is the most economically beneficial option, offering the highest IRR of 20.60% and 6.79% for commercial and residential buildings, respectively, and the shortest payback periods of 4.6 years and 11.2 years, respectively. These results provide valuable insights to guide building owners and designers in choosing the most cost-effective type of roof insulation for new or existing projects.

As of 2022, roughly 79.8% of Malaysia’s population resides in urban areas, increasing the population density of its cities. The hot and humid climate in Malaysia necessitates the constant use of air conditioning, especially in cities, resulting in high residential electric consumption and carbon emissions. The residential sector significantly contributes to global climate change, accounting for 27% of global energy consumption and 17% of carbon emissions. To address this concern, the local framework of the National Low Carbon Cities Masterplan (NLCCM) is advocating for a minimum 33% reduction in carbon emissions by 2030 in urban settings, aligning with the commitments made at the 15th Conference of Parties (COP 15). The aim of this study was to determine the energy consumption and carbon emission of residential areas in a tropical city, as well as explore potential energy and carbon savings. Utilizing the Intelligent Communities Lifecycle–Intelligent Community Design (iCL-iCD) energy simulation software, a digital twin of Bertam City, Penang, was developed. This digital model included 65.4% residential housing, which, in the specific scenario under study, accounted for 36% of the city’s electrical energy consumption for cooling purposes only. An early simulation of the residential areas of the city estimated the baseline energy consumption and carbon emissions to be 607 GWh and 314,736 tCO2e, respectively. Several energy-efficient measures were applied to the residential area of Bertam City, revealing a potential saving of 37.3% in both energy and carbon emissions.

The urban population in Malaysia has increased to 77.7% in 2021, from 66% two decades ago, of which the current percentage shows Malaysia has more than 25 million city dwellers out of the 32.7 million total population. This statistic resulted in 80% of carbon emissions, roughly 200 million tCO ² e, being produced by the urban cities in Malaysia. To balance out the high number of carbon emissions from urban settings, our government has aimed to reduce 33% of carbon by 2030, aligning with the COP commitment by Malaysia in 2021, and later aiming for carbon neutrality by 2050. Carbon neutrality can be achieved by using digital twin technology, which can virtually represent any physical system, including a whole city to its real-world counterpart. Bertam, a city in Pulau Pinang is used as a case study in this study. A baseline simulation has been made of the digital twin city, resulting in 253 kWh/m ² of total energy consumption in 2021, and 1.75 tonnes of carbon per capita. The recent applications of active and passive design strategies will be applied to the virtual city, to obtain its potential energy savings and carbon reduction data. At the end of the study, the digital twin technology will discover the city’s potential energy savings and carbon reduction after the optimization.