Characteristics of ASTF integration with building Facade elementAdvantagesDisadvantagesWall based bull

Compared to conventional solar thermal equipment, ‘Active Solar Thermal Façade’ (ASTF) is a new building integrated solar thermal product, which allows integration of a solar thermal collecting device into a building envelope BI 6015 (e.g. wall, window, shading, or roof), thus creating both the shielding and solar energy collecting functions for the façade. Recently, many types of ASTFs have been found in market and applications of these ASTFs have also been discovered in various buildings globally. Although many works have been carried out in the ASTFs, certain levels of ambiguity still remains in several aspects: (1) type and classification; (2) advantages and disadvantages; (3) performance data and evaluation methods; (4) current status and future potential of the ASTFs application; (5) research problems and progress; and (5) opportunities for further development. To provide the clear answers to these questions, this paper will deliver a comprehensive critical review into relevant aspects of the ASTFs, which is obviously the most wanted information in the solar thermal sector. This review study will help in identifying the current status, potential problems in existence; and future directions of research, development and practical application of the ASTFs technology in buildings. The results of the study will help promote development of such a building integrated renewable energy technology and thus contribute to achieving the UK and international targets for energy saving, renewable energy utilization, as well as carbon emission reduction in building sector.