基于灰色马尔科夫模型的地埋管换热器温度变化研究

STUDY OF TEMPERATURE CHANGING AROUND GROUND HEAT EXCHANGER BASED ON GREY-MARKOV MODEL

地埋管换热器温度变化规律对于浅层地温能的开发、地源热泵系统的设计有着重要的意义。采用灰色马尔科夫模型对热源温度、环境温度,不同渗流条件下的实验数据进行趋势性和随机性的分析。结果表明,换热器的温度变化既有趋势性又有随机性,且随机性不可忽略;温度变化的趋势性可采用GM(1,1)灰色模型进行分析,其偏差与渗流速度及时间呈负相关关系;温度变化的随机规律可采用马尔科夫模型进行分析,随机量与渗流速度呈负相关关系,渗流速度越大,随机状态间分布越均匀。

Understanding the variation of temperature around ground heat exchanger is vital for the development of shallow geothermal energy as well as the designment of ground source heat pump system.Based on the Grey-Markov model,the trend and randomness of laboratory data obtained under different heat sources,environmental temperatures and seepage conditions were analyzed.The results demonstrate that both trend and randomness exist in the temperature changing and the randomness can’t be neglected.The trend of temperature changing can be analyzed by the GM(1,1)Grey-Model,in which the deviation is in negative correlation to the seepage velocity and the time.The randomness of temperature changing can be analyzed by the Markov model and the random variable is in negative correlation to seepage velocity.The larger the seepage velocity is,the more uniform the distribution between random states is.