Effect of Urban Heat Islands on the Air-Conditioning of an Operating Room

Local overheating due to anthropogenic infrastructures and the population needs for daily life has an important impact on healthcare facilities that operate with continuity, and thus need to guarantee strict indoor microclimatic conditions. The aeraulic systems serving operating rooms may be significantly affected by the increase in temperature and humidity levels. The air handling units work with high outdoor air changes per hour, 15 h(-1) or more, according to the standards. Urban overheating does not affect the operating blocks through the building envelope, as these rooms are typically located in internal areas of the buildings, but all-air systems operation is directly conditioned by variations in humidity and temperature, as the outdoor air is the heat transfer fluid treated. Furthermore, overheating worsens the performance of the chillers necessary for air cooling/dehumidification, determining increases in primary energy requirements, greenhouse gas emissions, and operating costs. This work intends to evaluate the effect of climatic variations on: energy demands, CO2 emissions, costs, and the possibility to hold the desired microclimatic conditions in an operating room. The cooling requirements clearly grow with increasing temperatures, but also a higher humidity level aggravates the energy demands. This latter aspect should not be underestimated when all-air systems are considered, in view of the fact that many of the typical countermeasures adopted to mitigate urban heat islands (use of green and blue spaces) have negative effects in this respect. A study in two Italian cities - developed through TRNSYS dynamic simulations - is presented to contemplate such contrasting driving forces.