Building thermal conditioning systems account for nearly half of energy consumption in commercial buildings, which collectively represent around 40% of primary energy use in many European countries and the USA. This thesis explores methods to reduce energy consumption in HVAC (Heating, Ventilation, and Air Conditioning) systems by examining their relationship with conceptual building design. Key design decisions significantly impact energy performance, while certain generation and storage components can restrict design flexibility. The study aims to quantify this influence on HVAC system dimensions, costs, emissions, and energy consumption, providing architects with a method for early design stages. To address the non-stationary effects of intermittent renewable energy sources and component efficiencies, a time domain system simulation is proposed using seven pre-configured HVAC system models. These include boilers, chillers, cooling towers, thermal storage, solar thermal collectors, and photovoltaic modules, each with a developed control strategy for annual quasi-stationary simulation. Performance profiles derived from simulations inform calculations of energy consumption, carbon emissions, and costs, employing the annuity method for cost assessment. Optimization techniques, including global bounded Nelder Mead and Exhaustive search algorithms, are used to determine system component dimensions that minimize costs and emissio
