Solar Heating Systems as a Viable Solution Towards Nearly Zero Energy Buildings

Abstract

Currently the building sector accounts for almost 40% of total energy consumption in the European Union (EU) making, the reduction in energy consumption and the increased penetration of renewable energy resources important measures in the EU’s effort to reduce its energy dependency and GHG emissions. To that end, 2018 was set as the year that all new buildings occupied or owned by public authorities ought to be Nearly Zero Energy Buildings (NZEB), while from the end of 2020 all buildings must be NZEB. In the present work, a feasibility analysis is performed concerning a typical (12 m2/ 0.65 m3) solar space and water heating system, utilized in a representative 100 m2 “reference house” designed according to the latest national Regulation on the Energy Performance which is in accordance with Directive 2010/31/EC and located in Thessaloniki in the northern part of Greece, as well as variations of the same building with different average Um values representing different options towards NZEB. For the energy calculations regarding the proposed solar systems and for the buildings heating loads, TRANSOL, a transient simulation software based on TRNSYS was used. Finally, for all cases a financial analysis was performed and the Net Present Value (NPV) and Discounted Pay Back Period (DPBP) were calculated. From the analysis it was apparent that a typical solar space and water heating system can provide a viable solution towards NZEB, with solar coverage and DPBP being influenced strongly by the type of construction of the building and the fuel substituted. In all cases the proposed system covers at least 50% of the total needs.