Evaluation of mixed mode ventilation cooling energy saving potential in nZEB: A case study in Southern Italy

Roberto Stasi,Francesco Ruggiero,Umberto Berardi,C Zilio,F Busato

doi:10.1051/e3sconf/202234301004

Roberto Stasi, Francesco Ruggiero + Show 3 more

Open Access

https://doi.org/10.1051/e3sconf/202234301004

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Abstract

In recent decades, reducing the energy demand of the building sector has become a major goal of global policies. Proper design of the building-plant system is hence strategic to achieve nearly zero energy building (NZEB) target. This paper reports the results of modeling the building-plant system of an NZEB in Southern Italy. The case study is a multi-family complex of eight dwellings located in Bari, in the Apulia region. The building project originates from the energy refurbishment of a former industrial shed that was demolished and rebuilt for residential use. The planned HVAC system foresees the combined use of primary ventilation with fan-coil units fed by two ground source heat pumps (GSHP) supplied by eight vertical probes. Three hybrid ventilation strategies have been compared to evaluate the potential cooling energy saving: the first one examines an earth-to-air heat exchanger (EAHX), the second one proposes night hybrid ventilation from 10 pm to 6 am, and the last considers the adoption of free cooling in mechanical ventilation. Economic and energy comparisons among these three approaches are reported. Using EAHX, the cooling consumption saving reached about 20.7% The use of night ventilation combined with MVS can reduce the cooling energy demand for 14.4%, while free cooling in MVS produces a less effective decrease in the electricity consumption for cooling of about 7.7%. All three strategies generate major benefits in the middle-season.

Highlights

Reducing energy consumption and increasing energy efficiency in the building sector are key objectives that the European Community has been pursuing in the last decades
Using EAHX, the cooling consumption saving reached about 20.7% The use of night ventilation combined with mechanical ventilation system (MVS) can reduce the cooling energy demand for 14.4%, while free cooling in MVS produces a less effective decrease in the electricity consumption for cooling of about 7.7%
The study presented in this paper demonstrates that reaching nearly zero energy building (NZEB) targets for existing buildings is still one of the greatest challenges for the current design

Summary

Introduction

Reducing energy consumption and increasing energy efficiency in the building sector are key objectives that the European Community has been pursuing in the last decades. The residential sector alone represents 26.1% of final energy consumption and 16.6% of gross inland energy consumption [2]. Such significant shares highlight the reasons for the growing importance of European energy policies to act on the European building stock. Its energy performance in terms of non-renewable primary energy demand, its thermal transmittance, and its plant system efficiency must be lower than the value of a baseline building of the same shape, function, and plant system, but with standard baseline properties according to regulation (U-value, g-value, plant performance ratios, etc.)

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