Modeling and Performance Analysis of the Condenser Using Untreated Sewage Heat Energy

Sewage condenser is the critical component which affects the performance of the direct sewage source heat pump unit. The sewage directly flows into the condenser and transfers heat with the refrigerant. The performance of sewage condenser is different from the general water source heat pump units because of the characteristic of sewage. This paper developed a theoretical model with distribution parameters based on some reasonable simplification, and this model was applied to predict the performance of some sewage condenser and the effects of different tubes and pass arrangements on condenser performance were analyzed. The results show that there is little effect on the sewage condenser performance with different pass arrangement. The condenser heat exchange increases linearly with the rise of sewage inlet temperature when the sewage flux and refrigerant inlet conditions are fixed. The condenser heat exchange and flow resistance increase with the sewage flux raises when the sewage inlet temperature and refrigerant inlet conditions are constant. In addition, the change extent of heat exchange is similar with that of the flux change.