Design and development of a novel 22kW(th) hot water generation system comprising a biomass-gasification unit in the core and an integrated fire-tube water heat exchanger in the annulus is reported. Producer gas from the gasifier is combusted in a burner and the resulting hot flue gases are routed back through the helical tube to heat the water contained within the annular shell. This allows recovery of the thermal energy typically lost from the outer surface of a conventional gasification system. The simple design improvisation leads to a doubling of the overall efficiency ( approximate to 48 %) compared to a standard system with physically separated gasifier and heat exchanger units (approximate to 24 %). The developed system holds promise in domestic and industrial water heating applications. Overall, this integrated design presents an efficient and environment-friendly waste-to-value concept and proposes a meaningful use of the underutilized 36 EJ/annum potential of biomass from crop residue globally. (C) 2019 Elsevier Ltd. All rights reserved.