SOLAR-THERMAL SYSTEMS IMPLEMENTED IN COMMUNITIES OF COLLECTIVE HOUSEHOLDS FOR DOMESTIC HOT WATER PRODUCTION.

The built environment in communities is responsible for at least 40% of the entire energy consumption in the EU. This environment is closely analyzed under the national and European strategies aiming to increase sustainability in the communities through energy efficiency actions and the use of renewable energy sources. Once these European objectives are met, optimistic scenarios show that the solar-thermal (ST) systems will be able to provide from 3.6% of the amount of the thermal energy demand in 2020, up to 15% in 2030, and 47% in 2050. The EU energy strategy demands that by 2030 all new buildings should be able to entirely cover the energy amount needed for heating / cooling and domestic hot water (DHW) by using ST systems, whereas the old buildings will have to cover at least 50% of the amount needed for heating / cooling and DHW by using ST systems. This paper proposes a novel methodology to design optimized ST systems implemented at district level, while developing various implementation scenarios; a comparative analysis of individual projects (e.g.: for one apartment blocks), groups of multi-family houses (2, 5, 10 apartment blocks) up to districts (25 and 50 apartment blocks) allows for the optimal sizing of the feasible and affordable ST arrays, also making use of the already existent complementary infrastructure for DHW. A case study (Taberei District - Odorheiu Secuiesc Town, Harghita County) validates the methodology and outlines that district DHW production, entirely based on ST systems, supports the lower initial investment and payback time. [ABSTRACT FROM AUTHOR]