Comparative Analysis of Passive Design in Tropical Urban Housing Complexes

Thesis Abstract

In tropical urban contexts, rapid urbanization has intensified energy demand for cooling, yet many housing complexes underutilize passive design strategies due to fragmented planning and limited interdisciplinary collaboration. This study investigates the effectiveness of passive design interventions in reducing operational cooling loads and improving occupant comfort across four representative tropical city housing complexes, with the aim of generating transferable design guidance for dense urban developments. The specific objectives are to (1) quantify the impact of passive strategies—climate-responsive orientation, shading devices, natural ventilation corridors, stack effect, thermal mass, and roof/ facade treatments—on indoor temperatures and occupant comfort; (2) compare performance across self-contained, mid-rise, and high-density ground-to-roof typologies; (3) identify barriers to implementing passive design in policy, procurement, and maintenance contexts; and (4) formulate a decision-support framework for integrating passive design in tropical urban housing projects. The study employs a mixed-methods research design. The population comprises 16 buildings within four large-scale tropical urban housing complexes in a Southeast Asian metropolis, with a purposive sample of 12 representative blocks featuring diverse typologies and orientations. Data collection instruments include (i) in-situ environmental monitoring using data loggers to record temperature, relative humidity, solar flux, and air velocity at 0.6 m and 1.2 m above floor level over 12 months (n ? 6,000 data points per building); (ii) occupant surveys using a validated thermal sensation and comfort questionnaire administered to 360 residents; (iii) structured interviews with 24 facility managers and architects to capture design decision processes; (iv) building information modeling (BIM)-based simulations for baseline and post-intervention scenarios. Validity and reliability are ensured through triangulation, pilot testing of instruments, Cronbach’s alpha (>0.8) for the survey, and inter-rater reliability checks for qualitative coding. Analytical procedures incorporate a combination of quantitative and qualitative techniques. Descriptive statistics and time-series analysis summarize environmental conditions and comfort indicators; multivariate regression models quantify the relationship between passive design variables (orientation, shading ratio, window-to-wall ratio, natural ventilation rates, thermal mass) and normalized indoor comfort votes, controlling for occupancy and clothing insulation. ANOVA tests compare performance across housing typologies, while structural equation modeling (SEM) assesses the causal pathways among design interventions, energy savings, and occupant comfort outcomes. A discrete choice approach models resident acceptance and perceived effectiveness of passive strategies. Thematic analysis of interviews and open-ended survey responses identifies implementation barriers and maintenance considerations. A conceptual model synthesizes empirical findings with theories of passive solar design and biophilic comfort, drawing on the bioclimatic theory of thermal environments and the principles of Adaptive Comfort Theory. Key expected findings include (a) shading devices and optimized orientation contributing to a reduction of peak indoor temperatures by 2–4°C on hot afternoons; (b) natural ventilation achieving acceptable comfort levels during shoulder seasons with measured air exchange compatible with ventilation standards; (c) higher thermal mass moderating diurnal temperature swings, particularly in mid-rise blocks, leading to improved perceived comfort; (d) substantial energy demand reductions (20–35%) when passive strategies are integrated with minimal mechanical cooling; and (e) distinct constraints related to retrofit feasibility, retrofit costs, and maintenance regimes limiting widespread adoption. The study contributes to knowledge by providing robust, context-specific evidence on the performance of passive design in tropical urban housing and a transferable decision-support framework that integrates architectural, environmental, and socio-economic dimensions. It offers policy recommendations for streamlined procurement that prioritizes passive design, design guidelines for tropical housing typologies, and a scalable methodology for post-occupancy evaluation in similar urban settings. The main conclusion anticipates that well-coordinated passive design interventions, when aligned with occupant behavior and maintenance planning, can significantly reduce cooling loads and improve comfort without compromising housing provision or cost, thereby informing future tropical urban housing policies and practice through a practical, evidence-based toolkit. Recommendations include developing standardized passive design checklists for early-stage planning, embedding thermal comfort metrics in building codes, and establishing long-term monitoring programs to support iterative design improvements.