Hellenic renewable energy policies and energy performance of residential buildings using solar collectors for domestic hot water production in Greece

Abstract

Total final energy consumption in Hellenic buildings reached 6.5 × 106 tons of oil equivalent (Mtoe) or 34.2% of the total (2010), of which 4.6 Mtoe in residential buildings. National implementation of the European Directive on the energy performance of buildings (EPBD) in Greece since 2010 is the first coordinated attempt to improve the energy performance of Hellenic buildings. In this framework, as of 2011, new buildings have an annual solar fraction of 60% for sanitary hot water production from solar thermal systems. Efforts are currently underway to comply with the EPBD recast so that by the end of the decade, all new buildings are nearly zero-energy buildings and that the very low amount of energy required should be covered to a very significant extent by energy from renewable energy sources (RESs). At the same time, the unprecedented financial crisis and escalating energy costs in Greece have reemphasized the need to explore the opportunities of renewables and energy conservation measures (ECMs). This paper reviews the relevant RES policies and status, with an emphasis to the Hellenic buildings. Using Hellenic typical residential buildings, the national requirements, and methodologies, this work quantifies the benefits of using solar thermal collectors to cover 100% of the domestic hot water demand. The results illustrate that, even as a single action, this popular ECM can improve the energy class of existing residential buildings and in some cases even reach an energy class-B, which is the minimum requirement for new buildings. Combining with other cost effective ECMs and exploiting RES for space heating and cooling can help building owners to not simply comply with new regulations but most important reduce the operational cost of buildings while maintaining a comfortable indoor thermal environment.