Passive Cooling Strategies: Current Status and Drivers of Integration into Policy and Practice within ASEAN's Building Sector

Executive Summary

The ASEAN region is experiencing rapid economic growth and urbanisation, leading to a significant increase in energy demand, particularly for space cooling. This surge in energy consumption poses challenges for sustainability and environmental impact, necessitating the exploration of innovative solutions. Passive cooling strategies in building design and construction emerge as a vital component in addressing these challenges, offering a means to enhance energy efficiency in buildings while reducing reliance on active cooling systems. A pressing need for sustainable energy solutions exists in the ASEAN region, considering the anticipated rise in energy demand for space cooling. It establishes passive cooling strategies as a critical approach to enhancing energy efficiency and reducing environmental impacts, thereby addressing the dual challenges of energy consumption and climate change. The implementation of passive cooling strategies in the ASEAN context face both challenges and opportunities due to the region’s hot and humid climate. While high temperatures (25°C to 35°C) and humidity levels (often exceeding 70%) complicate cooling efforts, they also inspire innovative design solutions. Most importantly, high performance building envelopes with insulated roofs, walls and window glazing offer the greatest benefits in terms of maintaining comfortable indoor temperatures and reducing cooling loads. Where appropriate, natural ventilation can be harnessed through strategic building orientation and window placement, reducing reliance on mechanical cooling. Shading devices, high thermal mass materials, and reflective surfaces can effectively mitigate solar heat gain and reduce building energy use intensity. By leveraging these strategies, ASEAN countries can address their unique climatic challenges while promoting sustainable, culturally relevant building practices that improve comfort and reduce energy consumption. Through the use of simulation parameters such as Predicted Mean Vote (PMV), Predicted Percentage of Dissatisfied (PPD), and unmet hours, the report presents valuable insights into thermal comfort across different climatic conditions. The findings indicate that both passive cooling and hybrid scenarios significantly enhance thermal comfort compared to base cases. Additionally, the active design scenario provides the most consistent thermal comfort, although it may lead to increased energy consumption. Furthermore, passive cooling strategies applied to a baseline building design result in lower PPD values, suggesting that fewer occupants are dissatisfied with the thermal conditions. Reducing unmet hours is also essential for improving overall comfort and requires identifying areas for design improvement. These strategies are crucial for optimizing passive cooling strategies, particularly in subtropical climates. The report also addresses significant policy challenges that impede the broader adoption of passive cooling strategies, including regulatory inconsistencies and a lack of enforcement mechanisms. To overcome these challenges, it offers actionable recommendations, such as the development of comprehensive building codes that incorporate passive cooling principles and the establishment of training programs for architects and builders. These initiatives are essential for creating a supportive regulatory environment that encourages the integration of passive cooling techniques.

In conclusion, the report underscores the importance of embedding passive cooling strategies within the ASEAN Plan of Action for Energy Cooperation (APAEC) 2021-2025. It calls for sustained collaboration among stakeholders to tackle existing challenges and promote sustainable building practices. The findings reveal that passive cooling strategies are underutilized despite their significant potential to reduce energy consumption and greenhouse gas emissions. Therefore, the report advocates for a transformative shift towards sustainable building practices through the adoption of passive cooling strategies, which are vital for achieving energy efficiency and environmental sustainability in the ASEAN region.