Optimising zero energy buildings: performance analysis of a hybrid renewable energy system with hydrogen storage in Iran

A hybrid building energy system is investigated that combines high-visible-transmittance transparent-PV glazing, an air-based building-integrated PV/thermal collector, a battery, and seasonal hydrogen storage supplying a fuel cell. System operation is supervised by a reproducible rule-based intake controller for the air-source heat pump. Hourly interactions are simulated in TRNSYS 18 for Tehran’s hot-dry climate. Performance is evaluated in terms of energy and carbon outcomes, thermal comfort (PMV/PPD), daylight metrics, daylight autonomy (DA) and useful daylight illuminance (UDI), and tariff-agnostic techno-economics using capital recovery factor, levelised cost of electricity/hydrogen, and simple payback. Compared with a conventional ASHP baseline, annual grid purchases decrease by 82.3%, operational carbon falls to ∼637 kg yr−1, and comfort remains within PMV≈−0.05 / PPD≈9.4%. Dimming-enabled daylighting reduces electric-lighting demand by ∼28% while maintaining high illuminance adequacy (DA/UDI). Weekly operating profiles illustrate source-air selection and heat-pump COP response, and benchmarking places the proposed system within the upper range of performance reported for similar climates. The study delivers a transparent, implementable control policy and an integrated TPV–BIPV/T–battery–H2 architecture with a portable evaluation frame. Findings are scoped to hot-dry conditions, with transfer to other climates requiring retuning of thresholds, component sizes, and tariffs. Sensitivity and limitations are discussed to ensure reproducibility and cautious generalisation.