Thermodynamic and exergoeconomic analysis of a non-domestic Passivhaus retrofit

Abstract

This paper presents a thermodynamic and exergoeconomic analysis of a recently-retrofitted Passivhaus non-domestic building. The selected case study, a Community Centre located in London, underwent a deep-energy retrofit in 2011, becoming the first 'non-domestic Passivhaus' retrofit in the country. As the building was retrofitted per Passivhaus standards, which is based solely on First Law analysis, a thermodynamic investigation can provide a novel means by which to assess its exergy efficiency and cost-effectiveness. As such, the aim of this paper is to conduct a comprehensive exergy and exergoeconomic analysis, presenting novel performance indicators for the pre-retrofit and post-retrofit Passivhaus building. First law outputs show that the improvement presents high levels of energy savings (75.6%), reductions in carbon emissions (64.5%), and occupant thermal comfort improvement (28.8%). Second law outputs present a reduction in primary exergy input reduction of 56.4% and exergy destructions of 60.4%, leading to improve building exergy efficiency from 9.8% to 18.0%. Nevertheless, exergoeconomically the building did not perform as expected due to high capital cost and exergy destructions cost rates. These results give an insight into the thermodynamic impact of the Passivhaus approach, providing a critical assessment of the strengths and limitations of the standard under both thermodynamic laws.

Thermodynamic and thermal comfort optimisation of a coastal social house considering the influence of the thermal breeze

“…Assuming that thermal comfort is related to a minimum of exergy consumtion, Schweiker and Shukuya [54] compared an exergetic comfort model (human body exergy consumption (HBx-) rate) with the established adaptive comfort model and predicted mean vote (PMV) model, finding a linear relation between adaptive and exergetic model under neutral conditions. A review on the most recent building exergy literature can be found in Hepbasli [55] and García Kerdan et al [56].…”

Exergy Analysis of Energy Systems in Buildings

“…Based on this principle, Garcia Kerdan et al developed a comprehensive multi-objective model embedded into the well-known open-source dynamic building energy simulation tool, EnergyPlus [27,28], with the aim to allow for the exergy optimization of possible retrofit strategies for buildings. This model was applied to the retrofit of a three-story non-domestic Passivhaus in the UK [29]; here space heating and DHW were provided by means of a centralized conventional gas boiler and high temperature radiators. The retrofit solution included the installation of a GSHP unit and medium temperature radiators, as well as a mechanical ventilation system with a 90% efficient heat-recovery unit.…”