Experimental and numerical characterization of heating domestic appliances for energetic efficiency improvement

Abstract

Every year 5 million of boilers for domestic heating are sold in the European Union (EU). Because heating contributes to more than 20% to the whole energy use in the EU strategies for energy saving are of great interest. Currently in the European Union, efficiency requirements on boilers are becoming more and more stringent: following the common target of the energy reduction, European directives 2005/32/EC on the eco-design of energy-using products and 2009/125/EC on the energy-related products, oblige the labeling of boilers and water heaters in performance categories. Furthermore, EU policy is to phase out appliances with low performance, by no longer giving the right to be sold on the European market. The regulation on the Energy related products (Erp) which enters into force from 26th of September 2015 sets efficiency bans so that low efficiency boilers are going to be excluded from EU market. As a consequence, boilers manufacturers should face significant investments in terms of efficiency oriented product-development. Furthermore, robust measurements become necessary to establish correct performance categories and not generate conflicts with surveillance bodies. In the present PhD thesis work, carried out at Ariston Thermo Group in Osimo R&D center, experimental and modeling activities have been performed and reported concerning domestic heating appliances. A comprehensive analysis of energy fluxes has been carried out on domestic methane supplied gas boilers, different methods for efficiency estimation have been compared with related measurement uncertainties. The boiler energy balance closing problem has been undertaken through a novel statistical approach, subsequently, an uncertainty related risk analysis has been performed on space heating efficiency and water heating efficiency according to Erp regulation. Afterward, appliances insulation testing methods have been set-up and compared, in particular an automated test rig has been constructed and thermal camera measurements have been performed. Using such methods, boilers and tank losses have been characterized... [edited by Author]