机构地区: 天津大学机械学院热能与制冷工程系
出 处: 《太阳能学报》 2006年第11期1137-1141,共5页
摘 要: 对实际运行的U型埋地换热器长期性能进行了实验研究。根据灰色理论,建立了换热量和传热系数等参数的GM(1,1)预测模型,预测结果与实际测试具有较好的吻合性。管埋地换热器在长期运行过程中,由于冬夏负荷之间的不平衡问题,夏季工况很可能会出现恶化现象,其工况可分为过渡区、稳定区和衰减区3个阶段。引入无量纲运行时间τ来表征平均传热系数的长期运行特性,即K=aτb,并初步确定了夏季工况的时间域:过渡区τ=0~25%,稳定区τ=25%~80%,衰减区τ=80%~100%。灰色预测能够为系统的稳定运行、性能评价以及进一步优化提供定量化参考依据。 Experiments on the long-term behavior of U-shaped ground coupled heat exchangers (GCHE) were carried out. Based on the grey theory, GM( 1,1 ) model was established and further topological prediction was given for key parameters including heat-exchange rate and the coefficient of heat transfer. Simulated results showed that there is a better coinci- dence between the test and predicted data. During the long-term operation of the GCHE, heat transfer is likely to become worse and worse especially in the summer, due to the unbalance of the load. The summer mode can be divided into three working zones, namely: transitional period, steady period and weakening period. A dimensionless runtime was introduced to express the variation of the heat transfer coefficient. For the above three working zones, the range of dimensionless rtmtime is determined as 0 ~ 25% ,25% - 80% and 80% ~ 100%, respectively. Grey prediction can provide us with a quantitative basis for stable operation and next optimization of the ground source heat pump system.
领 域: [动力工程及工程热物理] [动力工程及工程热物理]