Ali H. Tarrad^*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.4, pp. 1111-1127, 2022, DOI:10.32604/fdmp.2022.021541

Abstract An analytical model was built to predict the thermal resistance of a vertical double U-tube ground-coupled heat pump that operates under steady-state conditions. It included a geometry obstruction factor for heat transfer throughout the backfill medium due to the presence of the second loop. The verification of the model was achieved by the implementation of five different borehole configurations and a comparison with other correlations in the available literature. The model considered a U-tube spacing range between (2) and (4) times the U-tube outside diameter producing a geometry configuration factor range of (0.29–0.6). The results of the model were utilized… More >

Yanxue Li^1,*, Weijun Gao^1,2, Xiaoyi Zhang², Wenya Xu¹, Yingjun Ruan³, Yinzhong Wang⁴

Energy Engineering, Vol.119, No.1, pp. 63-81, 2022, DOI:10.32604/EE.2022.016209

Abstract The building sector contributes a large ratio of final energy consumption, and improving building energy efficiency is expected to play a significant role in mitigating its carbon dioxide emission. Herein, we collected the on-site measurement data to investigate the techno-economic performances of different heat pump types that exist in building space heating projects in Qingdao, China. An in-depth analysis revealed the temperature variations of measured low-grade heat sources over the whole heating supply period, and urban sewage water shows high stable heat energy quality compared with seawater and geothermal heat resources. Operational behaviors including cycling inlet and outlet temperature of… More >