Journal of Scientific Research and Reports

Background: Energy constitutes a fundamental driver of economic growth, wealth creation, and social development, with buildings accounting for a substantial proportion of global energy consumption and consequently exerting significant environmental impacts.

Aims: The study aims to identify the important factors that affect the energy efficiency in various types of buildings and to compare the energy efficiency of various types of buildings so that buildings can be classified as energy efficient, neutral or energy inefficient based on quantitative comparison.

Study Design: Analytical and simulation-based comparative study of residential and institutional buildings supported by manual heat-loss calculations and building energy simulation using EQUEST software.

Place and Duration of Study: Department of Civil Engineering (Structural Engineering), College of Technology and Engineering, Maharana Pratap University of Agriculture & Technology (MPUAT), Udaipur, Rajasthan, India, between 2024 and 2026.

Methodology: Three primary buildings were selected (1300 ft² single-storey, 1200 ft² three-storey and a 44500 ft² E-shaped institutional building) along with a 100 ft² square reference unit. Annual electricity consumption and demand were simulated using EQUEST freeware building energy analysis program considering parameters such as floor area, number of floors, shape of floor and direction of windows. Comparative manual heat-loss calculations (q = UAΔT) were performed for buildings of varying size (10'×20', 20'×50', 40'×50', 50'×50') and varying shape (circle, square, rectangle, parallelogram, triangle). For each major design parameter, the percentage contribution to overall energy efficiency was estimated.

Results: EQUEST software simulations yielded efficiencies of 35.77%, 34.46%, 55.5% and 74.05% for the 1350 ft² single-storey, 1200 ft² three-storey, 44500 ft² E-shaped and 100 ft² square buildings respectively. As area increases, efficiency decreases because energy consumption increases while demand remains relatively stable. The 10'×20' standard building was 4 times, 9 times and 11.5 times more efficient than the 20'×50', 40'×50' and 50'×50' buildings respectively. Among shapes, circular plans exhibited 214% higher efficiency than square standard. Rectangle with minimum dimension 10' showed 100% efficiency. Triangle and small rectangles (10'×5') showed negative efficiency (−50%). Window orientation (north-east) contributed 1.46% efficiency gain. Sealed windows/doors contributed 1.75-fold efficiency, solar water heaters 1.81-fold, building insulation 1.84-fold, star-rated appliances 25-fold, fixture upgrades 1.80-fold, ventilation 1.95-fold, smart technology 1.70-fold, cool roofs 1.85-fold, eco-friendly materials 1.77-fold, landscaping 1.75-fold and alternative energy 1.71-fold.

Conclusion: Building size and shape are the most weighted factors for energy efficiency without which a building cannot be efficient. Heat loss is the major factor of energy efficiency and temperature is a salient factor of heat loss. Orientation, insulation and ventilation have major roles in efficiency. Buildings with positive efficiency are energy efficient and good for occupant health. Installation of energy-efficient systems contributes to sustainable development goals and aligns with India's commitment to reduce greenhouse gas emissions by 35% by 2030.