Feasibility Study of Self-Sufficient Solar Cooling Façade Applications in Different Warm Regions

Abstract

Small-scale systems and integrated concepts are currently being explored to promote the widespread application of solar cooling technologies in buildings. This article seeks to expand application possibilities by exploring the feasibility of solar cooling integrated façades, as decentralized self-sufficient cooling modules on different warm regions. The climate feasibility of solar electric and solar thermal concepts is evaluated based on solar availability and local cooling demands to be met by current technical possibilities. Numerical calculations are employed for the evaluation, considering statistical climate data; cooling demands per orientation from several simulated scenarios; and state-of-the-art efficiency values of solar cooling technologies, from the specialized literature. The main results show that, in general, warm-dry climates and east/west orientations are better suited for solar cooling façade applications, compared to humid regions and north/south orientations. Results from the base scenario show promising potential for solar thermal technologies, reaching a theoretical solar fraction of 100% in several cases. Application possibilities expand when higher solar array area and lower tilt angle on panels are considered, but these imply aesthetical and constructional constraints for façade design. Finally, recommendations are drafted considering prospects for the exploration of suitable technologies for each location, and façade design considerations for the optimization of the solar input per orientation.These systems have been researched and developed, mostly focusing on their performance, but their application in the built environment remains mostly limited to large demonstration projects and pilot experiences [7]. In that regard, several small-scale designs and prototypes are being developed by researchers, in order to promote widespread architectural application of these technologies in buildings, under the concept of solar cooling façades [5]. These integrated concepts seize the economic and functional benefits derived from the integration of decentralised components in the façade, while using the available exposed area for direct and diffuse solar collection. Economic benefits from façade integration refer to the construction cost savings and extra leasable space from avoiding complex distribution systems and large equipment [8,9], and functional advantages range from efficient energy usage by identifying local demands, to increased comfort due to personal control [10]. On the other hand, the façade not only comprises available external surface, but also directly influences indoor comfort. In warm climates, peak solar irradiance in façades usually match peak cooling demands in the adjacent offices, so it makes sense to harvest that radiation to drive a cooling system, while blocking solar heat gains under a climate responsive façade design.Solar cooling façade concepts found in the literature are based either on solar electric processes, using thermoelectric modules [11,12], or solar thermal...

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