Patent ID: 7628122

Claim:
A method for operating a non-condensing boiler at maximum non-condensation efficiency, the method comprising the steps of: sensing a temperature of exchange water introduced into a heat exchanger of the non-condensing boiler and a temperature of supply water discharged from the heat exchanger by means of sensors, transmitting the sensed temperatures to a controller, and calculating an average temperature from the temperature of exchange water and the temperature of supply water at the controller; calculating a maximum concentration of CO 2 from the calculated average temperature based on information indicating a relationship of a dew point temperature with a concentration of CO 2 that is previously input into the controller; calculating a ratio of excess air (λ) from the maximum concentration of CO 2 using a combustion equation chosen depending on a fuel used; when the excess air ratio (λ) is calculated, setting a control target value for the excess air ratio (λ) from the calculated excess air ratio; when the control target value for the excess air ratio (λ) is set, calculating a target value of air flow suitable for a current consumption amount of the fuel from the set control target value; and performing feedback control with respect to the air flow target value and a value input from an air flow sensor, and supplying a greater amount of air than the air flow target value.