闭式热源塔制热工况运行性能分析

发布时间：2018-02-22 19:04

  本文关键词： 闭式热源塔 TRNSYS 模拟分析 运行特性 数值计算　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,可再生能源技术是降低采暖制冷能耗成本的关键措施之一。闭式热源塔热泵技术是一种通过输入少量高位能源,利用热源塔吸收空气中的热量,或向空气中释放热量,将低品位能源向高品位转移的新型、节能、环保的可再生能源技术,实现了建筑物冷暖空调终端无锅炉、无排碳、无电辅和高能效的目标。随着热源塔热泵技术的推广,其实际工程应用中暴露的问题也越来越多,为了热源塔热泵技术的发展,亟需对该技术进行必要的理论研究。本文首先根据传热学和热质交换原理,建立湿空气物性参数和闭式热源塔干工况、半干半湿工况、湿工况、喷淋工况的数学描述,并编译热源塔理论计算模型和湿空气物性参数计算模型。其次搭建闭式热源塔热泵系统实验装置,对整个系统的运行系统进行全面的监测记录,包括热源塔进出口溶液温度、溶液流量、空气温湿度、风机功率,水源热泵的进出口温度等,根据实验测量值对理论计算模拟值进行对比分析,验证模型的可靠性,并利用实验数据拟合喷淋工况下闭式热源塔空气对流换热系数的关联式以及室外空气温度与载热流体进口温度的关系表达式。最后采用MATLAB和TRNSYS联合仿真的方式对实验台闭式热源塔传热特性进行了研究。研究结果表明,所建立的闭式热源塔计算模块精确度较高,可以用于闭式热源塔热泵系统的模拟分析。在喷淋条件下、闭式热源塔内,从翅片换热器顶部至底部,空气焓值近似呈线性变化;对载热流体而言,翅片换热器上半部分换热强度比下半部分高。喷淋溶液温度最低处位于塔的中部位置,结霜现象最先从这里开始;为了保证实验台闭式热源塔热泵系统稳定正常运行,选取喷淋溶液的冰点必须低于-8.4℃,载热流体的冰点必须低于-12.7℃;在整个制热期间,热源塔空气侧的传热温差与载热流体侧近似相等,且大部分时间处于2~3℃之间;当空气温度低于5℃,相对湿度高于56.8%时,闭式热源塔热泵系统必须开启喷淋泵,否则将会出现结霜运行现象,不利于系统的正常运行;在整个制热期间,热源塔全热换热量为12305k W,显热换热量为8390k W,潜热换热量占全热换热量的31.8%,虽然热源塔吸热量以显热为主,但是潜热换热不容忽视。
[Abstract]:At present, renewable energy technology is one of the key measures to reduce the energy cost of heating and refrigeration. The new, energy-saving and environmentally friendly renewable energy technology, which transfers low grade energy to high grade, has realized the goals of no boiler, no carbon emission, no power auxiliary and high energy efficiency at the end of building cold and warm air conditioning. With the popularization of heat source tower heat pump technology, In order to develop the heat source tower heat pump technology, it is necessary to carry out the necessary theoretical research. Firstly, according to the principles of heat transfer and mass exchange, The mathematical description of the physical properties of wet air and the dry condition of closed heat source tower, the half dry and half wet condition, the wet condition and the sprinkling condition are established. The theoretical calculation model of heat source tower and the calculation model of physical parameters of wet air are compiled. Secondly, the experimental device of closed heat source tower heat pump system is built, and the whole system operation system is monitored and recorded comprehensively, including the temperature of the inlet and outlet solution of the heat source tower. The flow rate of solution, air temperature and humidity, fan power, inlet and outlet temperature of water source heat pump are compared and analyzed according to the experimental measurement value to verify the reliability of the model. The correlation expression of convection heat transfer coefficient of closed heat source tower and the relation between outdoor air temperature and inlet temperature of heat carrying fluid are fitted by experimental data. Finally, the simulation of air convection in closed heat source tower by MATLAB and TRNSYS is carried out. The heat transfer characteristics of the closed heat source tower are studied. The results show that, The calculation module of the closed heat source tower is accurate and can be used to simulate and analyze the heat pump system of the closed heat source tower. Under the spray condition, the air enthalpy changes approximately linearly from the top to the bottom of the finned heat exchanger in the closed heat source tower. For heat transfer fluid, the heat transfer intensity of the upper part of finned heat exchanger is higher than that of the lower part. The lowest temperature of spray solution is located in the middle of the tower. In order to ensure the stable and normal operation of the closed heat source tower heat pump system, the freezing point of spray solution must be lower than -8.4 鈩，

本文编号：1525076