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In supporting the phase-out of the fossil fuels, Roof Top Photovoltaic (RTPV) deployment has been adopted worldwide as an important step of a bottom-up driving pathway of citizens’ transformation to become net energy producers within the community of their localized building environment. However, the diverse bioclimatic conditions of this environment may affect the best RTPV implementation. This is facilitated by climate-related characterization and regional adaptation. Hence, the built environment globally as a function of the global horizontal irradiation (GHI), the local environmental parameters of the different climatic zones and the associated technological developments are surveyed.In this work, we have critically assessed the RTPV effect on the building's overall energy performance and found beneficial over a diverse range of moderate and warm climates. By applying adequate insulation beneath the RTPVs, the increased heating needs in winter in cold climates or higher nighttime cooling needs in summertime can be avoided. To design low-energy buildings, we propose an analytical framework based on the space energy coverage by RTPV and the global horizontal irradiation. Moreover, RTPV cooling at elevated temperatures improves the efficiency up to 20 % and increases the generated electricity up to 15 %. Increasing the RTPV efficiency with emerging technologies could extend the decarbonization of high-rise buildings with energy efficiency and RTPV measures. To accelerate the clean energy transition, rooftop PVs should be widely adopted for sustainable solar building applications. Combined with electrical storage, this will allow renewable energy resources to cover a large fraction of future building energy needs worldwide.

This data article refers to the paper ''Optimizing photovoltaic electric generation and roof insulation in existing residential buildings” [1].The reported data deal with roof retrofit in different types of existing residential buildings (single-family, multi-family and apartment complex) located in Milan (Northern Italy). The study focus on the optimization of envelope insulation and photovoltaic (PV) energy production associated with different building geometries, initial insulation level, roof constructions, and materials.The data linked within this article relate to the modelled building energy consumption, renewable production, potential energy savings, and costs. Data refer to two main scenarios: refurbishment (roof in need of replacement and insulation) and re-roofing (energy intervention for roof improvement). Data allow to visualize energy consumption before and after the optimization, selected insulation level and material, costs and PV renewable production (with and without energy storage). The reduction of energy consumption can be visualized for each building type and scenario. Further data is available on CO2 emissions, envelope, materials, and systems.

This data article refers to the research paper A model for the cost-optimal design of Nearly Zero Energy Buildings (NZEBs) in representative climates across Europe [1]. The reported data deal with the design optimization of a residential building prototype located in representative European locations. The study focus on the research of cost-optimal choices and efficiency measures in new buildings depending on the climate. The data linked within this article relate to the modelled building energy consumption, renewable production, potential energy savings, and costs. Data allow to visualize energy consumption before and after the optimization, selected efficiency measures, costs and renewable production. The reduction of electricity and natural gas consumption towards the NZEB target can be visualized together with incremental and cumulative costs in each location. Further data is available about building geometry, costs, CO2 emissions, envelope, materials, lighting, appliances and systems.

The choice of the most appropriate technologies in buildings is often a challenge at the design stage, especially when many different criteria are taken into account. Consequently, the decision process relies often on one criterion only, such as costs or energy savings. We propose a multi-criteria approach based on multi-attribute utility theory to assess alternative energy efficiency measures, explicitly considering both environmental and economic criteria. We apply it to the design of a new residential building in Milan (Italy), with the aim to maximize CO2 emission savings related to electricity and gas consumption, and to minimize embodied energy and investment costs. After modelling the building prototype, alternative energy efficiency measures are assessed and ranked according to the selected criteria.The building optimized through the implementation of the best performing measures showed an overall 90% reduction in operational primary energy compared to the baseline building. The inclusion of the embodied energy altered the energy performance calculations resulting in 55–67% reduction in total energy over a 10-year period, and 77–82% over a 30-year period. Results point to the importance of a comprehensive implementation of measures, such as thermal improvements, high efficiency equipment, appliances, and renewable energy generation. The paper demonstrates the feasibility of this framework to support the decision process from a multi-criteria perspective, proposing a flexible method that can be adapted to other building types, environmental conditions, materials and technologies. It also highlights the importance of considering both environmental and economic criteria when designing a new building. It stresses how the embodied energy should be a criterion for technology selection, as current strategies to reduce operational energy often increase the amount of energy embodied into buildings with environmental consequences. Keywords: Multi-criteria decision making, Energy efficiency measures, Embodied energy, Multi-attribute utility theory (MAUT), Building modelling and simulation, CO2 emission savings