Advanced solutions to improve heat recovery from wastewater in a double heat exchanger

Abstract

One of the main challenges in the world today is reducing energy consumption and CO2 footprint in existing buildings without major construction work. The main component of energy consumption in buildings is heating, but the demand for the domestic hot water is also very high, especially when daily consumption is high and especially for specific applications. The implementation of technologies using recovery sources for water heating has become very important and one of these technologies involves the recovery of the thermal energy from wastewater. Usually, heat recovery from wastewater is designed to recover residual energy from the hot drainage water and this recovered energy is used to preheat incoming cold water or to heat pumps. The paper presents numerical simulations using a SST k-ω turbulence model in order to compare a regular geometry with a helicoidal one. The second one provides a more turbulent flow that allows an intensification of the outer flow, thus allowing the enhancement of the heat transfer from the inner heated flow to the outer flow.