Revising the definition of anthropogenic heat flux from buildings: role of human activities and building storage heat flux

[摘要] Buildings are a major source of anthropogenic heatemissions, impacting energy use and human health in cities. The differencein magnitude and time lag between building energy consumption and buildinganthropogenic heat emission is poorly quantified. Energy consumption( Q EC ) is a widely used proxy for the anthropogenic heatflux from buildings ( Q F,B ). Here we revisit the latter'sdefinition. If Q F,B is the heat emission to the outdoorenvironment from human activities within buildings, we can derive it fromthe changes in energy balance fluxes between occupied and unoccupiedbuildings. Our derivation shows that the difference between Q EC and Q F,B is attributable to a change in the storage heatflux induced by human activities ( Δ S o-uo ) (i.e. Q F , B = Q EC - Δ S o-uo ). Using building energysimulations (EnergyPlus) we calculate the energy balance fluxes for asimplified isolated building (obtaining Q F,B , Q EC , Δ S o-uo ) with different occupancystates. The non-negligible differences in diurnal patterns between Q F,B and Q EC are caused by thermal storage (e.g.hourly Q F,B to Q EC ratios vary between − 2.72 and5.13 within a year in Beijing, China). Negative Q F,B canoccur as human activities can reduce heat emission from a building but thisis associated with a large storage heat flux. Building operations (e.g.opening windows, use of space heating and cooling system) modify the Q F,B by affecting not only Q EC but also the Δ S o-uo diurnal profile. Airtemperature and solar radiation are critical meteorological factorsexplaining day-to-day variability of Q F,B . Our newapproach could be used to provide data for future parameterisations of bothanthropogenic heat flux and storage heat fluxes from buildings. It isevident that storage heat fluxes in cities could also be impacted byoccupant behaviour.

[学科分类] 医学（综合）