Latent Heat Recovery in Exhaust Gas of a Condensing Boiler: The Effect of Arrangement of Tubes

Boilers are one of the major energy consumers in the building. For this reason, increasing the efficiency of this device and improving its performance is an effective step in solving the problems in building energy and reducing waste energy. Due to the limited resources of fossil fuels and the increasing cost of energy in the world, manufacturers of these equipment are always working to improve the performance and use of appropriate control equipment. The purpose of this study is to increase the thermal recovery efficiency of steam energy in gases from shell and corrugated tubes condensing boilers. Numerical simulations are performed using commercial CFD code, ANSYS FLUENT 18.2. In this research, the effect of different arrangement of tubes in a shell and corrugated tubes condensing boiler are analyzed numerically. There are 10 tubes with three different arrangements inside the shell. The results show that the first model has clearly better heat recovery performance than the other two investigated models because of its irregular position of the tubes. The numerical model is validated by experimental results. According to the comparison of the results, the maximum difference is 6.9% and 8.9%. So simulation result shows good agreement and accuracy. Also, 10 pipes with 3 different configurations are used inside the tube. results reveal that nonlinear and irregular configuration is better than two other models.