Domestic Hot Water

Authors

MICHAEL RIDGE CENG, MIMECHE
Principal Engineer, FairHeat
michael.ridge@fairheat.com

GARETH JONES BSC (HONS)
Managing Director, FairHeat
gareth.jones@fairheat.com

The delegates of CIBSE Technical Symposium 2022 voted across the two-day event and nominated this research as the most significant contribution to the art and science of building services engineering.

Abstract

The ADE CIBSE Heat Networks Code of Practice (CP1 2020) (2), now has a minimum requirement that for kitchen hot water outlets, a temperature of 45oC must be delivered within 45 seconds. Historically, this has not been met by most heat networks.


Delivery time trials were undertaken to determine a design approach for acceptable delivery times. The key finding is that the additional time created by the pipe cooling down to ambient between usage events has a significant impact on the total delivery time, which is not currently accounted for at design. The paper presents empirical data and equations as a first stage to establish advice as to how to allow for the warm up time during design. Further research is required to create a robust industry standard.