Andreas K. Athienitis

Hybrid renewable microgrids that feed Proton Exchange Membrane (PEM) electrolyzers enable off-grid hydrogen production but require integrated design, sizing and control for good performance. We developed a Digital Twin (DT) of a solar-wind microgrid that supplies a PEM electrolyzer coupled with an energy storage system for a year-round assessment. The workflow starts with a solar standalone system on MATLAB/Simulink to assess the pattern of hydrogen production. Then a wind source is added to the system to provide complementary power generation and assess how it affects the hydrogen production pattern. Finally, the system is taken to Python environment for optimization, it couples detailed component models with Particle Swarm Optimization (PSO) and Model Predictive Control (MPC) for short-horizon dispatch. This study tracks electrolyzer loading, battery state of charge (SoC)and hydrogen output under measured meteorological data. In the final configuration, the PV generation is sized at 1.0 of the electrolyzer’s rated power, the wind turbine at 0.53 and the battery has a power limit of 0.40 with an energy capacity of 6.7hours at full electrolyzer load. Over a year-long simulation, the electrolyzer operates continuously with an annual capacity factor of 0.68 on an LHV basis and an average hydrogen production of 48.7 kg/day. The battery supplies an average of 13% of the electrolyzer’s demand with the remainder being covered by the renewables. The electrolyzer’s specific consumption is 50kWh/kg of hydrogen.

This paper investigates the design and performance of an air‐based building‐integrated photovoltaic/thermal (BIPV/T) system for sloped roof applications using colored PV modules. Two colors (terracotta and gray) are evaluated through experimental testing under controlled laboratory conditions to assess the impact of surface color on system behavior. Mechanical ventilation effectively reduced PV temperature by up to 13°C (1.49 m/s channel air velocity), with terracotta modules exhibiting slightly higher temperatures mainly due to color reflectance differences. Thermal efficiencies ranged between 13.9–28.6% for the terracotta and 12.5–27.3% for the gray prototype. While the proposed system achieved thermal efficiencies comparable to those reported in previous studies, commonly used convective heat transfer correlations failed to capture the behavior of the system accurately. A new empirical correlation tailored to the examined setup is introduced. This work contributes to the advancement of knowledge on colored BIPV/T systems by demonstrating that colored PV modules integrated into mechanically ventilated roof assemblies can support significant heat recovery while providing architectural design flexibility. By enabling both electricity generation and thermal recovery, colored BIPV/T systems enhance the energy efficiency and perceived economic value of solar‐integrated building envelopes, supporting sustainable building design and low‐carbon construction practices.

This study presents a novel switchable multi-inlet Building integrated photovoltaic/thermal (BIPV/T) curtain wall system designed to enhance solar energy utilization in commercial buildings. The system integrates controllable air inlets and motorized dampers that dynamically adjust airflow patterns in response to real-time environmental conditions such as solar irradiance, ambient air temperature, and PV panel temperature. A steady-state energy balance model, developed using a thermal network analogy and implemented in Python, was used to simulate winter operation in Montréal, Canada. Three operating modes with different air inlet configurations were assessed to evaluate system performance across variable air velocities and solar conditions. Results indicate that the switchable system improves combined thermal and electrical generation by 2% to 25% compared to fixed one- or two-inlet systems. Under low irradiance and air velocity, one-inlet operation is dominant, while higher solar gain and airflow favor two-inlet configurations. The system demonstrates effective temperature control and enhanced energy yield through optimized airflow management. This work highlights the potential of integrated control strategies and modular façade design in improving the efficiency of solar building envelope systems and offers practical implications for scalable deployment in energy-efficient, heating-dominated climates.

This paper investigates the potential of a novel, infrastructure-integrated photovoltaic/thermal (IIPV/T) system for winter road maintenance, using the Samuel De Champlain Bridge in Montreal as a case study. Vertically mounted bifacial PVT panels are integrated into the bridge’s side barriers, serving a dual role as wind protection structures and clean energy generators. The captured solar energy is used in real time and stored seasonally to power a hydronic heating system (HHP) for anti-icing the bridge deck.The system is modeled using NREL’s System Advisor Model (SAM) with Typical Meteorological Year (TMY) data for Montreal. Simulations estimate that approximately 45% of winter heat demand can be met directly from IIPV/T generation, while 20% is supplied via seasonal thermal storage, and the remaining 35% is surplus. A comparative energy analysis between the Champlain Bridge and an existing Swedish system is presented. Economic analysis indicates a payback period of 2.1–2.5 years, with additional benefits from grid-connected surplus electricity.This study demonstrates the technical and economic feasibility of using IIPV/T systems for sustainable anti-icing of large-scale infrastructure. Limitations such as structural load effects and detailed pipe heat losses are noted and recommended for future work.