Heating energy savings potential from retrofitting old apartments with an advanced double-skin façade system in cold climate

Apartments account for over 60%of total residential buildings and consume a significant portion of primary energy in South Korea.Various energy efficiency measures have been implemented for both new apartment constructions and existing apartment retrofits.Old apartment structures have poor thermal performances,resulting in a high energy consumption.The South Korean government initiated retrofitting projects to improve the energy efficiency in old apartments.Apartment owners typically replace old windows with high-performance windows;however,there is still a demand for better and more innovative retrofit methods for a highly improved energy efficiency.This paper proposes an advanced double-skin façade(DSF)system to replace existing balcony windows in old apartments.Considering the cold climate conditions of Seoul,South Korea,it mainly discusses heating energy savings.Three case models were developed:Base-Case with existing apartment,Case-1 with typical retrofitting,and Case-2 with the proposed DSF system.The EnergyPlus simulation program was used to develop simulation models for a floor radiant heating system.A typical gas boiler was selected for low-temperature radiant system modeling.The air flow network method was used to model the proposed DSF system.Five heating months,i.e.,November to March,and one representative day,i.e.,January 24,were selected for detailed analysis.The main heat loss areas consist of windows,walls,and infiltration.The results reveal that the apartment with the DSF retrofit saves 38.8%on the annual heating energy compared to the Base-Case and 35.2%compared to Case-1.

TOWARDS AN ACTIVE, RESPONSIVE, AND SOLAR BUILDING ENVELOPE

The key role of the building envelope in achieving building energy efficiency and indoor comfort for the user has been long established.The most promising-and innovative-strategy for the building envelope of the future is based on a dynamic,active and integrated solution,that is able to optimize the thermal performance,integrate the active elements and systems,and exploit energy from renewable sources.This paper illustrates the most relevant results of a decade-long research activity carried out on active and integrated building envelopes at the Politecnico di Torino,in which numerical analyses and experimental campaigns,involving test cells and field monitoring,have been performed.The overall performances of different façade modules and the thermo-physical behaviour of various components,under different operating strategies,are presented and discussed.The analysis provides information on the contribution of each subsystem,e.g.glazing,sun-shading devices,natural and mechanical ventilation,...to the achieved energy efficiency and the overall performances of different typologies of Double-Skin Façades(DSFs)and Advanced Integrated Façades(AIFs).

Energy characterization of forced ventilated Photovoltaic-DSF system in hot summer of composite climate

Performance of Photovoltaic-double skin façade(Photovoltaic-DSF)system in summer has been critical.Owing to high solar ingress,cooling requirement of a building significantly increases.Photovoltaic-DSF system provides a shield and controls the heat gain through fenestration in the interior spaces.In the present article,mathematical correlations are developed for energy characterization of forced-ventilated Photovoltaic-DSF system in India’s hot summer zone i.e.Jaipur.The Photovoltaic-DSF system has been installed and monitored for Jaipur’s summer months(May to July).L25 Orthogonal array of design parameters(air cavity thickness,air velocity,and PV panel’s transparency)and their respective levels have been developed using Taguchi design to perform experiments.Based on experimental results,multiple linear regression has been used to forecast solar heat gain coefficient,PVs electrical power and daylighting illuminance indoors as function of design factors.The statistical significance of mathematical relationships is sorted by variance analysis,which is found to be in good accord with field measurements(R2>0.90).The proposed correlations are pragmatic in designing Photovoltaic-DSF systems for hot summer conditions.The Photovoltaic-DSF system with 30%transmittance and air velocity of 5 metres per second in 200 mm air cavity thickness achieved maximum energy performance in hot summers.