Harvesting rainwater from rooftops could help cities stay cool and cut the number of heat wave days
Collecting rainwater from rooftops and using it to spray buildings during hot weather could help cities cut air conditioning use, lower urban temperatures and lessen the impact of heat waves, according to new research from The University of Manchester.
Harnessing rainwater from rooftops to cool buildings during heat waves could help cities cut energy use, lower temperatures, and minimize the effects of extreme heat, according to fresh research from the University of Manchester. As global temperatures soar, cities confront mounting pressures on health, infrastructure, and energy systems.
Air conditioning becomes a go-to for staying cool, but it guzzles energy and adds more heat to urban areas. Rainwater harvesting technologies offer a promising solution to curb excessive heat, yet water availability often hampers their adoption. The study, published in Earth's Future, employed process-based simulations and AI to evaluate a system that accumulates rooftop rainwater and automatically sprays it on structures during sweltering weather.
In Tokyo, the researchers observed that cooling roofs cut down air conditioning energy needs, lowered indoor heat transfer, and diminished waste heat emissions, thus reducing overall city temperatures and diminishing heat wave frequency and severity. Dr. Zhonghua Zheng, lead author and expert at Manchester Environmental Research Institute, emphasized that cities worldwide grapple with increasing heat challenges.
While air conditioning offers relief, it also guzzles energy and emits extra heat. The study suggests that collecting rooftop rainwater and employing it judiciously for cooling presents a practical avenue to curb both energy use and urban heat. Timing proved more crucial than tank size or water volume, with larger tanks offering marginal additional advantages.
Moreover, pouring extra water did not always enhance cooling, as some remained on the roof instead of evaporating. The researchers suggest that this approach could aid local authorities and urban planners in assessing the viability of rainwater-based cooling systems in their locales, weighing factors such as cost, water availability, and regulations.
As heat waves intensify, the team posits that roof-based rainwater cooling systems could complement broader urban climate adaptation measures, bolstering resilience and safeguarding public health.
Written by urgent.news from Phys.org's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
