Design Optimization for Net Zero Energy Apartment Buildings in Lebanon: A Parametric Performance Analysis

Buildings have a significant impact on energy use and the environment, accounting for approximately 20% of global energy consumption and 40% of CO2 emissions. The US Energy Information Administration predicts that rising living standards and populations in non-OECD nations, including Lebanon, will inevitably lead to a significant hike in electricity demand, leading to a 50% rise in global energy consumption and exacerbating climate change. However, realizing energy efficiency in residential buildings remains a significant challenge for many countries such as Lebanon due to non-existent legislative frameworks and absence of green construction practices. As a result, energy consumption in Lebanon is a significant source of economic distress, social inequity, and air pollution. Approximately half of the Lebanese electric generation is consumed by the residential building market. Despite this, energy conservation measures (ECMs) have not been widely adopted in standard Lebanese apartment buildings, the most prevalent archetype of housing in the nation. 

This dissertation evaluated the feasibility and applicability of Net Zero Energy apartment buildings (NZEB) in Lebanon’s residential sector. To address these issues, 1,110 individuals in the US and Lebanon were surveyed to gain a deeper understanding of the perceptions and potential of NZEBs in Lebanon. Additionally, the dissertation examined the effects of various passive and active ECMs on energy consumption in a baseline multi-family apartment building, utilizing an incremental multi-stage iterative building performance modeling and simulation approach. Simulation results identified the following variables as the most optimal energy indicators: insulated envelope, highefficiency HVAC & DHW systems, high- performance glazing, high-efficiency lighting and equipment, and a compact square footprint. These combined variables yielded a 56% reduction in energy use over the baseline. Thereafter, building optimization yielded a NZEB with PV integration. Accordingly, the dissertation generated targeted architectural guidelines toward energy optimization for NZEB in Lebanon, encompassing passive and active design strategies. The guidelines were validated via survey responses from 152 Lebanese respondents. Finally, the dissertation provided a framework for an informational NZEB mobile based app to provide Lebanese homeowners, students, and building professionals with design guidelines to achieve NZEB in Lebanon. 

Adopting a NZEB approach offers households resiliency, autonomy, and improved financial stability. They also offer robust options for improving environmental justice, social equity, and economic stability. The dissertation promotes sustainable residential building practices to reduce energy use, mitigate air pollution, combat climate change, and eliminate energy inequities. The fundamental premise of the dissertation is providing Lebanese people a viable path towards eliminating energy poverty, providing social inequity, and reducing financial strain. The dissertation aims to equip Lebanese households with Resiliency and Immunity from potential future crises. The dissertation findings clearly show that NZEB are feasible as a new design and construction paradigm within Lebanon’s multi-family sector and that transitioning the existing residential market into Net Zero Energy is now within reach.