Multi-Objective Optimization of Design nZEBs in Uzbekistan

Abstract

The growth in energy demand from the residential sector in Uzbekistan points to the urgency to adopt nearly zero-energy building (nZEB) strategies that can be tailored to domestic climate and economic conditions. The present building stock, represented by weak thermal performance, results in excessive energy consumption for heating and cooling and excessive CO₂ emissions. To address this, the study examines multi-objective optimization methods for residential building retrofitting via integration of advanced insulation systems and renewable energy technology. The calculation uses heating and cooling degree days (HDD/CDD), which is in compliance with national standards ShNK 2.08.01-24 (Thermal Protection of Buildings) and KMK 2.01.04-18 (Building Climatology), to determine energy loads, taking techno-economic factors into consideration in terms of cost-effectiveness. Simulations were conducted for a typical three-room house, varying insulation thickness (0–50 mm), solar collectors, and photovoltaic panels. Results show that particular annual energy requirements decreased from 53.9 to 34.6 kWh/(m²·yr), and CO₂ emission decreased from 45.44 to 18.84 kg/(m²·yr) with improved insulation. Additionally, payback periods decreased from 8.94 to 8.45 years, confirming economic feasibility. The findings suggest that enhanced retrofitting coupled with solar technologies can greatly reduce operational energy usage and environmental impact, offering a sustainable solution for residential development in Uzbekistan.