Deploying solar reflective materials on urban surfaces is known as an effective heat mitigation strategy. Several studies have shown their cooling impacts; however, most of them have focused on rooftops rather than facades. The novelty of this paper is related to exploring the impact of each façade orientation on the corresponding microclimate and energy balance. High albedo materials were implemented on facades with different orientations to explore the potential of each façade. Computer simulations were employed to calculate the insolation of different façades, ground surface temperature, and surface energy balances. The simulations are done for the longest day of the year (21st of June) to have the maximum solar radiation on all facades. The results showed that east-west canyons receive 6 h more direct sun than north-south canyons. This proved that eastern and western facades have the most impact on the microclimate. Cooling east and west facades led to the maximum net radiation reductions for the ground surface. Furthermore, north and south facades had negligible contributions to pedestrian thermal comfort. By understanding the role of each façade, designers and policy makers could deploy cooling materials more effectively on building surfaces.

在城市表面部署太阳光反射材料被称为一种有效的热缓解策略。几项研究表明它们对冷却有影响。但是，它们大多数都集中在屋顶而不是外墙上。本文的新颖性与探索每种立面方向对相应微气候和能量平衡的影响有关。在不同方向的立面上采用高反照率材料，以探索每种立面的潜力。使用计算机模拟来计算不同立面的日照量，地表温度和表面能平衡。在一年中最长的一天（6月21日）进行模拟，以使所有立面上的太阳辐射最大。结果表明，东西峡谷比南北峡谷多接收6小时的直射阳光。这证明了东西两面对微气候的影响最大。东西立面的冷却导致地面的最大净辐射减少。此外，南北立面对行人的热舒适性的贡献可忽略不计。通过了解每个立面的作用，设计师和决策者可以更有效地在建筑物表面上部署冷却材料。