NT-87-11-4 -- Field Testing of a Condensing High-Density Commercial Water Heater

A gas-fired commercial water heater has been developed, which achieves high efficiency by operating in the condensing mode. Laboratory testing has demonstrated a steady-state efficiency above 95% and standby losses less than 1.0 %/h. To verify that this level of performance is achieved under actual usage conditions, nine prototype models of the condensing water heater have been field tested at representative commercial sites across the country. The results obtained in the field tests are presented, analyzed, and discussed in this paper. The demonstrated advantages of the condensing water heater in comparison to conventional designs are described in terms of efficiency improvement and corresponding gas savings. Analyses of the field data are also presented, which provide useful insights into the effects of usage conditions and patterns on water heater performance.

Units: Dual