Towards the objective of Net ZEB: Detailed energy analysis and cost assessment for new office buildings in Italy

• Published in: Energy and buildings 2023-01, Vol.279, p.112707, Article 112707
• Main Authors: Di Turi, Silvia, Ronchetti, Laura, Sannino, Raniero
• Format: Article
• Language: English
• Subjects: Building energy modeling; Building energy performance; Dynamic thermal simulation; Economic feasibility; Energy efficiency; Investment cost; Net ZEB; Net zero energy building; Office buildings; Zero emission building
• ISSN: 0378-7788
• DOI: 10.1016/j.enbuild.2022.112707

•An integrated energy-economic analysis of Net ZEB office buildings was proposed.•A thorough discussion on the energy balance was provided for Italian climate zones.•Energy grid integrations, self-consumption, storage and losses were analyzed.•The cost assessment of office buildings was performed and compared to state-of-art.•The energy-economic benefit of a new Net ZEB office in Italy was demonstrated. Recently, the built environment has become one of the leading sectors in the challenge of decarbonization and energy consumption reduction. Because of the specific use and the complexity of the typological, architectural, and technical characteristics, non-residential buildings represent a challenge to overcome the nearly Zero Energy Building standard and to achieve the objective of Zero or Net Zero Energy Buildings. It is desirable that the energy produced in situ from renewable sources totally covers the energy demand (ZEB); alternatively, the amount of energy self-produced and dispatched into the grid must be greater than (or equal to) the energy withdrawn from the grid (Net ZEB). At the same time, it is necessary not to neglect the economic aspects. The aim of this work is to propose an integrated energy-economic analysis to demonstrate the actual feasibility of new Net ZEB offices in different Italian climate zones. Thus, the energy analysis of a reference building, based on consolidated and cost-effective envelope and HVAC systems, has been carried out through dynamic simulations. The photovoltaic field located on the roof provides the energy needed for lighting, appliances, and HVAC. The obtained results are the energy demand and the energy production from renewable sources for the case study in each Italian climate zone. Moreover, the paper discusses the complexity of the annual energy balance, considering contributions such as grid integrations, self-consumption, energy stored and losses. Finally, the cost assessment of the proposed building has been carried out and compared to the state-of-art, pointing out the economic feasibility of the Net ZEB.