In the framework of international actions to reduce the energy requirements and greenhouse gases emissions due to buildings, a new International Energy Agency task has been recently established in order to study Net Zero Energy Buildings (NZEBs). The commonly shared concept of NZEB, is a building whose annual balance of energy consumptions tends to zero. This concept is still too imprecise and the authors of this paper participate to the activities of SubTask B of IEA Task40 with the aim of establishing an internationally agreed understanding on NZEBs. The task is based on a common methodology for identifying and refining design approaches and tools to support industry adoption of innovative demand/supply technologies for NZEBS. This goal is pursued through detailed modeling and analysis of specific NZEB case studies. Among the specific objectives of the Sub Task B it is possible to include the analysis of redesigned studies. Redesigned studies should identify better alternative solutions for plants, building envelope or impact on the environment that significantly modify the building. To provide high quality information about the design process of a NZEB, it was decided to examine in detail the specific case study of the Leaf House (LH) located in Ancona, Italy. The studied building is fully monitored in terms of thermal environment, energy production and consumption, water use and occupancy. The purpose of this paper is to present some optionsto improve the performance of the selected building, identified by using the collected data and analyzing a detailed TRNSYS model of plant-building complex. The model has allowed detailed evaluation of the effects of some changes in the design that can improve the behavior of the Leaf House in terms of consumptions of energy resources and environmental impact of the building. The performed analysis shows that the building envelope is already very effective in terms of thermal performance, while the redesign of the thermal plants and the PV system should permit to reach a nearly net zero energy performance.
Citation: ASHRAE Conference Papers, Montreal, QC