Influence of microclimate boundary conditions in net zero energy settlements on HVAC efficiency

Abstract

Net zero energy buildings (NZEB) represent reality of new constructions in Europe for environmentally sustainable energy efficiency. The shift to net zero energy settlements represents a further opportunity to achieve extra-energy saving, thanks to utilities sharing, renewables optimization, and microclimate mitigation. This last aspect concerns the opportunity to improve settlements outdoor microclimate conditions in both hot and cold seasons, in a variety of climate conditions, with the purpose to improve occupants’ wellbeing. At the same time, microclimate mitigation at inter-building scale may also involve relatively less severe boundary conditions able to reduce both cooling and heating demand of buildings and better working conditions for HVAC systems, e.g. heat pumps and air-to-air heat exchangers. This extra-energy saving, achievable with no extra costs, may represent an interesting opportunity to be taken into account in net zero energy settlements design and construction. This study analyzes this energy saving in a net zero energy settlement in Italy, built thanks to an on-going Horizon 2020 project. The influence of microclimate mitigation strategies is assessed in terms of energy saving benefits for the heat pump working conditions. Results demonstrate that this further benefit represents a non-negligible, environmentally sustainable, strategy for energy efficiency of NZEB in new inter-building scale developments.

Combined Effect of Outdoor Microclimate Boundary Conditions on Air Conditioning System’s Efficiency and Building Energy Demand in Net Zero Energy Settlements

“…The study is carried out within the framework of the ongoing Horizon 2020 ZERO-PLUS project, which has the goal of designing a market-ready, innovative, comprehensive, and cost-effective system for NZE residential settlements in Europe [21] to demonstrate their multidimensional sustainability. Building upon previous contributions [15,22], first, tailored weather files that take into account the potential outdoor microclimate mitigation were generated to be used as input boundary conditions in dynamic simulation. The files were developed considering the evidence of other environmental mitigation studies [23].…”