Ventilation Heat Recovery from Wood-Burning Domestic Flues. A Theoretical Analysis Based on a Triple Concentric Tube Heat Exchanger

Energies

Pierre Peigné²  Christian Inard¹ 

[1] LaSIE (Laboratoire des Sciences de l’Ingénieur pour l’Environnement), Department of Civil Engineering, University of La Rochelle, 17042 La Rochelle, France;CERIC Laboratory (Centre d’Essais et de Recherche des Industries de la Cheminée), Poujoulat Group, 79270 Saint-Symphorien, France; E-Mails:

关键词: low energy building;    air heating system;    wood pellet stove;    heat recovery ventilation;    triple concentric tube heat exchanger;    analytical solution;   

DOI  :  10.3390/en6010351

来源: mdpi

【 摘 要 】

This paper presents a new air-heating system concept for energy-efficient dwellings. It is a system designed to heat a low-energy building by coupling a heat-recovery ventilation system with a three-fluid heat exchanger located on the chimney of a wood-pellet stove. The proposed work focuses on the heat transfer that occurs between flue gases, the ventilation air and the combustion air within a triple concentric tube heat exchanger with no insulation at its outer surface. The main objective is to predict outlet temperature for the specific geometry of the heat exchanger studied here. Thus, the governing differential equations are derived for a counter-co-current flow arrangement of the three fluids. Then analytical solutions for the steady-state temperature distribution are obtained as well as the amount of heat transferred to the outside. An expression for the effectiveness of the heat exchanger is also proposed. Based on these results, calculations are performed on a case study to predict the fluid temperature distribution along the heat exchanger. Finally, a parametric study is carried out on this case study to assess the influence of the relevant parameters on the effectiveness of the heat exchanger. In addition, computation of heat losses to the outside justifies whether insulation is needed.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.