The condensing boiler technology has been known for at least two decades and its energy saving potential is nowadays acknowledged. Taking advantage from the additional heat recovered from the condensation of the water vapour contained in the exhaust flow, condensing boilers achieve, during test operations, efficiencies up to 108% on the LHV of natural gas.
However, the yearly global performance of such boilers strongly depends on the type of heating system installed downstream. Due to the operating temperature ranges of the device, the radiant floor seems to be the most suitable heating system for such boilers.
The present study evaluates the experimental data collected from a centralised plant, coupled to radiator and fan coil heating systems, over two years of operation. Although these medium/high temperature devices are not expected to fit at best to the condensing boiler, the yearly average performance reaches very high values
