MODELING SOLAR RADIATION IN STREET CANYONS IS CRUCIAL TO UNDERSTANDING THE SOLAR AVAILABILITY OF BUILDING FAÇADES. THIS ARTICLE DESCRIBES THE IMPLEMENTATION OF A SIMULATION ROUTINE, DEVELOPED IN THE MATLAB® COMPUTER LANGUAGE, WHICH IS AIMED AT PREDICTING SOLAR ACCESS FOR BUILDING FAÇADES LOCATED IN DENSE URBAN CONGLOMERATES COMPRISING DEEP LONG STREET CANYONS, UNDER HIGH SOLAR RADIATION CONDITIONS, TYPICAL IN SOUTHERN COUNTRIES OF EUROPE. METHODOLOGY IS PRIMARILY BASED ON THE CONFIGURATION FACTOR THEORY, ALSO AIDED BY COMPUTER SIMULATION, WHICH ENABLES TO ASSESS THE INTERPLAY BETWEEN THE SURFACES THAT COMPOSE THE SO-CALLED STREET CANYON. THE RESULTS OF THE THEORETICAL MODEL HAVE BEEN CROSS-CHECKED AND VERIFIED BY ON-SITE MEASUREMENTS IN TWO REAL CASE STUDIES, TWO STREETS IN CADIZ AND SEVILLE. THE SIMPLIFIED SIMULATION REPRODUCES THE SHAPE OF THE CURVE FOR ON-SITE MEASURED VALUES AND WEIGHTED ERRORS FOR THE WHOLE MODEL DO NOT SURPASS 10%, WITH A MAXIMUM OF 9.32% AND A MEAN VALUES OF 6.31%. AS A RESULT, A SIMPLIFIED PREDICTIVE MODEL THAT TAKES INTO ACCOUNT DIRECT, DIFFUSE AND REFLECTED SOLAR RADIATION FROM THE SURFACES THAT ENCLOSE THE CANYON, HAS BEEN DEVISED. THE AUTHORS CONSIDER THAT THIS RESEARCH PROVIDES FURTHER IMPROVEMENT, AS WELL AS A HANDY ALTERNATIVE APPROACH, TO USUAL METHODS USED FOR THE CALCULATION OF AVAILABLE SOLAR RADIATION IN URBAN CANYONS, SUCH AS THE SKY VIEW FACTOR OR THE RAY TRACING.

SOLAR PROTECTIONS ARE OFTEN DESIGNED AS PASSIVE STRATEGIES IN BUILDINGS, BOTH FOR THERMAL AND LIGHTING PERFORMANCE. IN THIS SENSE, THE IMPORTANCE OF THE BALANCE BETWEEN THESE TWO PARAMETERS COULD BE CRUCIAL IN THE EARLY STAGES OF DESIGN. THE PURPOSE OF THIS RESEARCH IS TO COMPARE THE VARIATION SOLAR PROTECTION STRATEGIES (GLAZING WITH SOLAR PROTECTION, AND THE LENGTH OF OVERHANGS) HAVE ON ENERGY AND LIGHTING, USING AS REFERENCE, THE VALUE DEFINED BY THE MODIFIED SOLAR FACTOR (MSF), USED IN SOME COUNTRIES LIKE SPAIN AND CHILE, TO RESTRICT SOLAR CONTRIBUTIONS. SIMULATIONS WERE CARRIED OUT TO UNDERSTAND THE POTENTIAL OF SOLAR PROTECTIONS WITH THE SAME MSF AND THE IMPLICATIONS ON THERMAL AND LIGHTING PERFORMANCE. THE CASE STUDY IS A CLASSROOM LOCATED IN TALCA, IN CENTRAL-SOUTHERN CHILE, WITH A CLIMATE OF MARKED SEASONS, INCLUDING COLD WINTERS AND HOT SUMMERS. THE RESULTS SHOWED THAT THE USE OF SOLAR PROTECTION STRATEGIES WITH THE SAME AND SIMILAR MSF VALUES DO NOT PROVIDE COMPARABLE ENERGY PERFORMANCE. SPECIFICALLY, THE DIFFERENCES IN ENERGY CONSUMPTION ARE 0.62 KWH (EAST (E) - MSF 0.14) FOR HEATING, IN COOLING 42.28 KWH (NORTHEAST (NE) - MSF 0.47), IN LIGHTING 5.30 KWH (NORTHWEST (NW) - MSF 0.11), AND 39.77 KWH IN THE TOTAL CONSUMPTION (NORTHEAST (NE) - MSF 0.47). ACCORDING TO THE RESULTS OBTAINED, SUITABLE SOLAR PROTECTION REQUIRES EVALUATING DIFFERENT ALTERNATIVES THAT ALLOW BALANCING BOTH PERFORMANCES, WHILE ATTAINING SIGNIFICANT ENERGY SAVINGS.