A Fast Prediction Model for Heat Transfer of Hot-Wall Heat Exchanger Based on Analytical Solution

• Published in: Applied sciences 2019-01, Vol.9 (1), p.72
• Main Authors: Hu, Wenju, Jia, Peng, Nie, Jinzhe, Gao, Yan, Zhang, Qunli
• Format: Article
• Language: English
• Subjects: Air conditioning; Aluminum; Architectural engineering; Ceilings; Civil engineering; Computer simulation; Condensers; Conduction; Conduction heating; Conductivity; Contact angle; Convection; Convective heat transfer; Cooling; Energy; Exact solutions; Heat exchangers; Heat flux; Heat recovery; Heat transfer; Heat transfer coefficients; High temperature; hot-wall heat exchanger; Households; Hydronic heating; mathematical model; Mathematical models; Metal foils; Model accuracy; Numerical analysis; Optimization; Pipes; Prediction models; Radiant cooling; Radiant heating; Studies; Thermal conductivity; Thermal engineering; thermal properties; Thermal resistance
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app9010072

The hot-wall heat exchanger (HWHE) has been widely used in thermal engineering fields such as ceiling radiant heating/cooling, refrigerator condenser, solar heat collection, and high-temperature heat recovery. However, the numerical simulation normally used for heat transfer prediction in HWHE is usually not as convenient as the analytic solutions in engineering applications. In this paper, a new heat transfer mathematical model of HWHE-based on analytic solutions was developed, which could be much faster to obtain the heat transfer properties of HWHE. The proposed model was validated under four conditions with literature values, which showed that the deviations of heat flux are 2.53%, 0.99%, 2.12%, and 1.96%, indicating its accuracy is satisfied. The model was then used to analyze the thermal property of HWHE. The results show the thermal resistance caused by panel with heat convection and conduction accounts for 96.54% of HWHE thermal resistance, and the thermal resistance caused by heat convection on the surface of panel is 74.43%. The analyzation results also show that adding aluminum foil around pipes could decrease HWHE thermal resistance by 5.11%. Besides, the influence of pipe diameters, pipe distance, pipe heat conductivity, side wall heat conductivity, and convective heat transfer coefficient on the heat transfer performance of HWHE was analyzed. The research in this paper can be used for fast prediction and optimization of heat transfer in HWHE.