Innovative metrics to evaluate HVAC systems performances for meeting contemporary loads in buildings

The significant impacts of the building sector ask for an urgent transition, which will be profoundly shaped by the HVAC sector. Due to recent energy demands modification, strongly associated to climate change consequences, buildings are asked to be equipped with HVAC systems capable of satisfying in a cost-effective way even contemporary space heating and cooling demands; in this context, the polyvalent heat pump (PHP) is recognized as a promising solution, being able to serve both requests simultaneously and independently, differently from the more widespread reversible heat pumps. However, despite the potentialities that the PHP could offer, still few efforts have been reserved to it in literature and existing metrics have proven not to be able to evaluate the capabilities of HVAC systems in meeting contemporary loads. Therefore, to fill this gap, through the development of a proper numerical model to investigate and simulate diverse systems operations on a common basis, the paper aims to develop new indicators able to include the assessment of the contemporaneity of request. To this purpose, the research: (i) proposes innovative technical indicators able to value PHPs performances, with particular attention to the assessment of the hours with contemporary space heating and cooling demands; and (ii) compares PHPs with other all-electric HVAC configurations using ad-hoc metrics, extending the discussion to other relevant domains, covering financial and environmental spheres. Thanks to the applicative study, the paper demonstrates the efficacy of the proposed indicators to evaluate the performances of HVAC systems for meeting contemporary loads in buildings, succeeding in valuing the technologies able to provide simultaneous heating and cooling services using a single unit. In addition, results highlight that PHPs can be considered a good trade-off from a multi-domain standpoint, emphasizing how this technology can be useful to drive the transition towards the electrification of thermal uses. (C) 2022 Published by Elsevier Ltd.