Solar Bridge Retrofit System: An innovative solution to renovate structural thermal bridge areas.

• An experimental study of a new innovative solar passive retrofit solution is studied. • The new design enables the heavy structure of the building to absorb solar radiation. • Proposed system may be used in combination with the traditional ETICS. • Indoor temperature may be increased in the range of 2-5ºC above outdoor in winter. • Results also imply that the system may provide heat gains throughout the day. The structural components of load-bearing concrete frame buildings, such as concrete beams and columns, are critical elements of the facades which often act as a thermal bridge. To reduce the impact of structural thermal bridge areas in non-retrofitted Portuguese residential buildings, a new innovative solar passive retrofit solution, named Solar Bridge Retrofit System (SBRS), is proposed. This concept relies on the principles of unvented Trombe wall systems and consists in using an external transparent skin in front of the structural areas of the envelope in combination with the traditional ETICS in the remaining area. Contrary to the traditional Trombe walls, this innovative design enables the heavy structure of the building to absorb solar radiation and conduct the heat slowly inward or to the adjacent structure. To evaluate the thermal performance of the SBRS, an experimental setup was developed. The field results obtained during February and March 2020 for two different configurations, showed that the double-glazing configuration in combination with ETICS has the potential to improve thermal comfort and reduce energy consumption. This paper addresses both the design of the SBRS and the obtained results from the experimental work. [ABSTRACT FROM AUTHOR]