Tecnologie per il residenziale e i servizi
Solar Heating and Cooling (residenzial)
Autors: SalvatoreTamburrino, Fabio Nardecchia, Fabio Bisegna
Solar heating and cooling technology plays a key role in climate change mitigation. In its Energy Roadmap to 2050 the European Commission indicates this technology as a "no-regret" options for "locally produced" energy and decentralized energy production and end-use. Nowadays, heating and cooling account for almost 50% of the final energy use. Although in the mid-long term heat demand in the EU could be moderated by energy efficiency policy measures (e.g. NZEB buildings), it is expected to remain a key part of the overall energy demand. The use of solar thermal energy has become a key option for both traditional applications (e.g., space heating and hot water) and more advanced applications for heat production in industrial processes.
Solar thermal systems (STS) use solar radiation to heat up a fluid (e.g. air, water or a special fluid) which can directly be used or transfer the heat to another fluid (through a heat exchanger) to provide e.g. space heating and cooling and/or hot water service. STS may also be equipped with heat storage (hot water tanks) and provide heat when solar radiation is not available. STS can be used not only for space heating and cooling in the residential sector, but also for a number of industrial and commercial applications such as swimming pools heating, heat and hot-water production for industrial process. The solar collector is the key component of a STS. The two dominant solar collector technologies are the flat solar collectors (FPC) and the evacuated tube solar collectors (ETC). These two types differ widely depending on local climate, heating and cooling demand and load profiles, and costs.The STS technology is relatively simple and most countries may produce locally components and systems through small and medium-sized enterprises, which also install and carry out system maintenance. Suppliers of STS are focused on diverse areas such as small, compact plug&play units, hybrid electric systems and large-scale plants (> 500 kW) that often include different applications. A number of countries in diverse world regions (e.g. Austria, Spain, Greece, Finland, Denmark, Argentina, Brazil, China, Turkey, Israel, Australia, South Africa) have successfully developed local production capacity, with associated economic benefits. Over the past decades, the deployment of STS has been very successful in a number of countries. In countries such as Cyprus and Israel between 80% and 90% of the residential buildings have STS for domestic water on their roofs . However, globally STS still meet only 1.2% of space heating and hot water demand in residential buildings. Recently, a number of advanced options are emerging with higher efficiencies and low costs than the current systems. STS integration into district heating systems as well as combined STS-heat pump systems to provide both heating and cooling also areas of further development