Urban heat islands (UHI) are a widely documented phenomenon that adversely increases urban overheating and, among other effects, contributes to heat-related mortalities and morbidities in urban areas. Consequently, comprehensive UHI-mitigating measures are essential for improving urban microclimate environments and contributing to salutogenic urban design practices. This study proposed urban cooling strategies involving different tree percentages and leaf area densities in a dense urban area during the summertime in Korea. The cooling effects of sixteen various combinations of proposed scenarios based on common urban tree types were studied via in-situ field measurements and numerical modeling, considering both vegetated and exposed areas. It was observed that by changing the characteristics of the leaf area density (LAD) per plant of our vegetated base area—for instance, from 4% trees to 60% trees, from a low LAD to a high LAD—the daily average and daily maximum temperatures were reduced by approximately 3 °C and 5.23 °C, respectively. The obtained results demonstrate the usefulness of urban trees to mitigate urban heating, and they are particularly useful to urban designers and policymakers in their efforts to minimize UHI effects.

Hybrid energy systems physically or conceptually combine various energy generation, storage, and/or conversion technologies to reduce costs and improve capability, value, efficiency, or environmental performance in comparison with independent alternatives. Hybridization is an interesting energy sector solution for plants to expand their flexibility, optimize revenues, and/or develop other useful products. Integrated hybrid energy systems’ improved flexibility can hasten the integration of more renewable energy into the grid and help become closer to the target of zero-carbon energy grids. This paper aims to provide an updated literature review of design and applications of hybrid energy systems in buildings, focusing on economic, environmental, and technical viewpoints. This current study will analyze current and future trends toward hybrid energy systems for buildings and their functions in electrical energy networks as potential research study topics for the future. This study aims to enhance sustainable building techniques and the creation of effective electrical energy networks by offering insights into the design and applications of hybrid energy systems. The methodology used in this study entails assessing present and potential trends, as well as looking at hybrid energy system uses and designs in buildings. The higher flexibility of integrated hybrid systems, which enables enhanced grid integration of renewables, is one of the key discoveries. The discussion of potential research study themes and conceivable applications resulting from this research forms the paper’s conclusion.