Economic and environmental comparison of natural gas fired conventional and condensing combi boilers

AbstractIn this paper, energy efficiency and life cycle cost economic analysis of conventional and condensing natural gas fired combi boilers in the individual heating systems are evaluated. The exit flue gas temperature of a conventional gas fired boiler is usually high and a great amount of heat energy is lost to the environment. In the flue gas, both sensible heat and latent heat can be recovered by adding a condensing heat exchanger. Thus, the condensing combi boiler efficiency can be increased by as much as 10%. For this purpose, equations of annual fuel consumption and condensed water vapour quantity are identified and also life cycle costs method has been used to analyse the feasibility of both combi boilers. It is found that condensing combi boiler can provide fuel saving ∼8% in comparison to conventional combi boiler in individual heating systems. In addition, the life cycle cost analysis showed that condensing combi boiler is cheaper than conventional combi boiler.