The integration of renewable energy and flexible energy sources in buildings brings numerous benefits. However, the integration of new technologies has increased the complexity and despite the progress of optimization algorithms and technologies, new research challenges emerge. With the increasing availability of data and advanced modeling tools, stakeholders in the building sector are actively seeking a more comprehensive understanding of the implementation and potential benefits of energy optimization and an extensive up-to-date survey of optimization in the context of buildings and communities is missing in the literature. This study comprehensively reviews over 180 relevant publications on the management and optimization of energy flexibility resources in buildings. The primary objective was to examine and analyze prior research, with emphasis on the used methods, objectives, and scope. The method of content analysis was used to ensure a thorough examination of the existing literature on the subject. It was concluded that multi-objective optimization is crucial to enhance the utilization of flexible resources within individual buildings and communities. Moreover, the study successfully pinpointed key challenges and opportunities for future research, such as the need for accurate data, the complexity of the optimization process, and the potential trade-offs between different objectives.

An indoor climate impacts human comfort, well-being, and safety. Therefore, it remains an important topic since, nowadays, people spend a significant amount of time indoors. Additionally, as tropical geographical zones become more populated, urbanised, and industrialised, the energy demand for air conditioning will rise significantly. In terms of the indoor climate, hospitals are particularly demanding due to the special needs of their occupants, however there is a paucity of studies about the tropics. Through a systematic analysis of accessible data and peer-reviewed articles, this study performed a quantitative and qualitative review of the scientific studies selected by the defined inclusion and exclusion parameters. A total of 65 tropics-related scientific publications, 28 on indoor thermal comfort and 37 on indoor air quality published between 2000 and 2023, were systematically reviewed. This study’s findings corroborated those from the previous studies, alluding that there is a paucity of scientific studies on the indoor climate conditions of buildings in tropical countries. A total of 42 studies (65%) were conducted in Asia and 15 studies (23%) in Africa. Six studies (9%) were reported in South America and two studies (3%) were obtained from Oceania, Australia. The results indicated that tropical Africa recorded the lowest number of indoor climate studies considering the population indices. Many of the reviewed indoor climate studies employed mixed methods, whereas only very few considered a seasonal approach. Meanwhile, in the developing tropics, only one record was found regarding an indoor climate study of hospitals based on their locations (correlating the outdoor and indoor air quality). Additionally, no record was found regarding the IC studies of hospitals in sub-Saharan Africa, in which, the IC impact on the occupant’s performance, productivity, and behaviour was assessed. Inferably, gaps still exist in the indoor climate of tropical hospitals. The current study highlights the need to improve the indoor climate considerations in the design, siting, awareness, regulations, and policy implementations concerning the hospitals in developing tropical countries. In conclusion, the study emphasises the need for more scientific studies on the indoor climate of tropical hospitals and highlights the relevant areas of the indoor climate studies in future works for considering the climate, environmental, socio-economic, infrastructural, and demographic peculiarities of the tropics for the betterment of hospital indoor climates in developing tropical countries.