Facade Integration of Solar Thermal Collectors: A Breakthrough

Abstract

One main barrier to the acceptability of façade use of solar thermal collectors is their black appearance and the visibility of piping or absorber irregularities through the glazing. To facilitate façade integration, a project was set up to develop selective filters reflecting only a small part of the solar spectrum in the visible range while letting the rest of the radiation heat the absorber. These filters were successfully produced and, combined with a diffusing glass treatment, have achieved the desired masking effect with minor impact on the collector efficiency (less than 10%). Glasses of various colours combined with several diffusing finishing (acid etching, structured glass etc…) can be produced that are able to hide the absorber. Such glazings will allow the use of the same product both in front of façade areas equipped with solar absorbers (as collector external glass) and in front of the non exposed areas (as façade cladding), opening the way to a broad variety of active façade designs. The active elements can then be positioned at will on the exposed areas, and their quantity determined only by thermal needs. By freeing the dimension of the façade area that can be clad with this glazing from the thermally needed surface for collectors, a major step to help architects use solar thermal on facades has been taken.

Building Integrated Solar Thermal (BIST) Technologies and Their Applications: A Review of Structural Design and Architectural Integration

“…On the whole, BIST is fundamental to possess the construction, hydraulic and hygiene characteristics (listed in Figure 11). In terms of the function, shielding, comfort maintaining and communication availability are the items to be addressed; In terms of the construction concern, protection from external intrusions, load-bearing capability, prevention of thermal bridge and moisture condensation, mechanical stress, stability, energy efficiency, thermal reservation, safety in use, provision to material volume expansion, as well as fitting with other envelop materials are the factors to be considered; In terms of hydraulic concern, prevention from the water leakage, and balance to the hydraulic pressure difference should be considered; And in terms of hygienic concern, health, environmental adaptability should be the issues to be addressed [50]. The common BIST components are relatively heavier than the conventional facade components, therefore risk assessment and management should be particularly addressed for achieving the safe installation.…”

Colored absorbers for solar thermal collectors a numerical study for Lebanese buildings

“…Many researchers agree that the integration of these components into the buildings' structure could represent an important solution to overcome most of these barriers [1][2]. The integrated components can work as multifunctional elements to replace some of the conventional building parts for a small extra cost, while adding many benefits in terms of energy reduction, and heat and acoustical insulation to the building.…”