Abstract: We designed a condensing heat pipe heat exchanger installed at the rear funnel of conventional gas water heater. We analyzed the impact of heat load and inlet flow volume on the exhaust sensible and latent heat recovery as well as the thermal efficiency of gas water heater. Experimental results show that heat load of the gas water heater has important impact on the recycled heat of heat pipe heat exchanger.With the increase of heat load of the gas water heater from 051 m3/h to 0.59 m3/h, the recovered sensible heat and latent heat respectively increase from 2 671 kJ/h to 3 283 kJ/h and 735 kJ/h to 1 126 kJ/h. The average thermal efficiency of the gas water heater can reach 94%, and the highest thermal efficiency can attain 101%.

Key words: condensing heat pipe heat exchanger, heat recovery, gas water heater, thermal efficiency