Numerical study on the thermal performance of water flow window fed with air-conditioning condensate

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Original languageEnglish
Article number125633
Journal / PublicationEnergy
Issue numberPart B
Online published18 Oct 2022
Publication statusPublished - 15 Jan 2023


A water flow window (WFW) fed with potable water is deemed as an effective system for absorbing incoming heat energy through the glazing area of a window. In this study, condensate formed in an air-conditioning (A/C) system is applied in a WFW for reducing heat gain and electricity consumption of a building. There is no need to consume any potable water. Through building energy simulations and numerical computation, this study unveils that a fully air-conditioned office building operating under a subtropical climate can produce condensate of sufficient flow rate to absorb heat energy from the glazing panes of an A/C condensate fed WFW system. The surface temperature of an outer glazing pane in an A/C condensate fed WFW system can be dropped by 16.3 °C when compared to a Low-e glass window. Moreover, an A/C condensate fed WFW can offer better thermal performance than a conventional WFW. When comparing to a Low-e glass case, an A/C condensate fed WFW facing four different orientations (N, E, S & W) can give reduction percentages of transmitted heat gain ranging from 57.2% to 63.5%. This A/C condensate fed WFW system shows a promising performance and has good potential for real application in commercial buildings.

Research Area(s)

  • Building energy simulation, Condensate recovery, Water flow window