Transformation of an Office Building into a Nearly Zero Energy Building (nZEB): Implications for Thermal and Visual Comfort and Energy Performance

Ilaria Ballarini,Vincenzo Corrado,Argun Paragamyan,Giovanna De Luca,Anna Pellegrino

doi:10.3390/en12050895

Abstract

Directive 2010/31/EU promotes the refurbishment of existing buildings to change them into nearly zero-energy buildings (nZEBs). Within this framework, it is of crucial importance to guarantee the best trade-off between energy performance and indoor environmental quality (IEQ). The implications of a global refurbishment scenario on thermal and visual comfort are assessed in this paper pertaining to an existing office building. The retrofit actions applied to achieve the nZEB target consist of a combination of envelope and technical building systems refurbishment measures, involving both HVAC and lighting. Energy and comfort calculations were carried out through dynamic simulation using Energy Plus and DIVA, for the thermal and visual performance assessments, respectively. The results point out that energy retrofit actions on the building envelope would lead to significant improvements in the thermal performance, regarding both energy savings (−37% of the annual primary energy for heating) and thermal comfort. However, a daylighting reduction would occur with a consequent higher electricity demand for lighting (36%). The research presents a detailed approach applicable to further analyses aimed at optimizing the energy efficiency measures in order to reduce the imbalance between visual and thermal comfort and to ensure the best performance in both domains.

Highlights

In the last few decades, the reduction in global energy consumption has been centrally involved in the scientific debate
Directive 2010/31/EU promotes the improvement of the energy performance of buildings and enforces the Member States to draw up national plans to increase the refurbishment of existing buildings in order to change them into nearly zero-energy buildings [1]
The fraction of free floating time of the total occupancy time for the Exist.B and nearly zero-energy buildings (nZEBs)* variants is shown in Figure 4 on a monthly basis

Summary

Introduction

In the last few decades, the reduction in global energy consumption has been centrally involved in the scientific debate. Directive 2010/31/EU promotes the improvement of the energy performance of buildings and enforces the Member States to draw up national plans to increase the refurbishment of existing buildings in order to change them into nearly zero-energy buildings (nZEBs) [1]. Energy refurbishment measures may have opposite effects on the thermal and visual performance, and may lead to a consequent imbalance between the two domains. They can, for example, reduce solar heat gains and lead to an improvement in thermal comfort during the cooling season, but at the same time can lead to a reduction in daylight supply and, as a consequence, to a higher energy need of electric lighting to provide visual comfort conditions

Methods

Results

Discussion

Conclusion