Document Type : Original Article
Author
Department of Mechanical Engineering, Yazd University, Yazd, Iran
Abstract
This study presents a techno‑economic analysis for retrofitting the Golgohar administrative building in Sirjan, Iran, toward ZEB‑oriented performance. The methodology integrates 3D modeling in SketchUp with dynamic energy simulations in EnergyPlus to evaluate passive shading systems (simple and smart roller shades and blinds) and active rooftop PV (20% efficiency, 110 kWp). Simulation results demonstrate that the smart interior roller shade reduces annual energy consumption by 14% (from 2,116 GJ to 1,817 GJ) by optimizing daylight and minimizing HVAC loads, significantly outperforming non‑smart devices which inadvertently increased heating demand by up to 13.7%. The PV system generates 789 GJ annually, supplying 57% of the building's electricity demand, with peak production aligning effectively with summer cooling loads. A critical economic evaluation across four energy pricing scenarios (Iranian subsidized tariffs, Energy Exchange, FOB Persian Gulf, and European market prices) reveals stark contrasts in financial viability. Under subsidized tariffs, the combined retrofit faces a prohibitive payback exceeding 28 years, while under European market prices, the payback drops to less than one year. This 42‑fold disparity underscores the decisive influence of energy policy on investment feasibility. Detailed discounted cash flow and sensitivity analyses confirm that subsidies not only suppress returns but exponentially amplify financial risk from inflation and discount rate volatility. The study validates a replicable, data‑driven framework for near‑ZEB retrofits in semi‑arid climates and concludes that policy reform is the single most critical lever for unlocking the environmental and economic potential of building energy efficiency in developing nations.
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