基于?优化的梯级潜热储能装置的模拟研究  

Numerical study of a cascade latent heat energy storage system based on exergy optimization

作　　者：杨耿 肖鑫 王云峰 YANG Geng;XIAO Xin;WANG Yunfeng(Institute of Air Environment and Building Energy Conservation,College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China;Yunnan Provincial Rural Energy Engineering Key Laboratory,Kunming 650500,Yunnan,China)

机构地区：[1]东华大学环境学院空气环境与建筑节能研究所,上海201620 [2]云南省农村能源工程重点实验室,云南昆明650500

出　　处：《储能科学与技术》2023年第12期3770-3779,共10页Energy Storage Science and Technology

基　　金：上海市科委浦江人才计划(20PJ1400200);云南省农村能源工程重点实验室开放基金项目(2022KF001);中央高校基本科研业务费专项基金(2232021D-11)。

摘　　要：为了解决热泵在利用低品位热能及可再生能源存在的时间和空间不平衡的问题,潜热储能技术常集成于热泵中。在该技术中,梯级潜热储能(CTS)装置的适配设计和填充相变材料(PCM)热物性的改善,对其耦合热泵系统的稳定和高效运行有重要影响。本工作基于多级热机?优化理论,针对太阳能热泵干燥系统设计了梯级潜热储能装置,介绍了依据焓法建立三维的壳管式CTS装置模型。选取乙酰胺作熔点改性剂的三水合乙酸钠(SAT)水合盐基复合PCM,作为CTS装置中熔点梯级排布的填充物。为研究其蓄热过程的传热特性和热管理性能,本工作对壳管式三级CTS装置和分别填充3种不同配比PCM的单级潜热储能装置进行了数值模拟,并模拟了75℃定温和太阳能集热热水的变温蓄热过程。结果显示,减少梯级潜热储能装置级之间的热传递可提高蓄热量;在三级CTS装置变温进水的相变蓄热阶段,平均进出口温降达4.41℃,可使峰值温度降低0.90%,对进口温度具有一定的缓冲作用,较单级蓄热装置的工作温度区间广;三级CTS装置蓄热密度是同体积生活热水蓄热水箱的2.39倍,可对太阳能集热器产生的波动热源进行有效蓄热,整体的出口温度均匀性和换热功率优于单级蓄热。本研究可为梯级PCM的制备提供指导,为CTS装置和材料协调优化研究提供新的思路。Latent thermal energy storage(LTES) technology is employed to rectify the imbalance of time and space in the application of low-grade heat and renewable energy in heat pumps(HPs).The adaptive design of cascade latent thermal energy storage(CTS) devices and the improvement in the thermophysical properties of phase change materials(PCMs) have a crucial effect on the stable and efficient operation of coupled HP drying systems.Based on the exergy optimization of multistage heat engines,a CTS device was designed for a solar HP system,and a threedimensional shell-tube CTS model was established according to the enthalpy method.Physical constraints such as the phase change temperature of the target material and practical application conditions were comprehensively considered,and the theoretical calculation results provided guidance for the selection and improvement of PCMs,in addition to the adjustment of the heat exchanger size.In this study,sodium acetate trihydrate(SAT)-based composite PCMs were used as the filling PCMs with a cascade layout in the CTS device,which were prepared by the addition of different concentrations of acetamide(AC) to adjust the melting temperatures.To investigate the heat-transfer characteristics and thermoregulation performance of the thermal storage processes,three-stage shell-tube CTS device and single-stage LTES device filled with three ratios of SAT/AC were numerically investigated using constant and variable inlet temperatures of solar hot water.The results revealed that the reduction in the heat transfer between the stages of the CTS device could improve the thermal storage capacity.In the latent heat-storage stage of the three-stage CTS device,the average inlet and outlet temperatures decreased by 4.41 ℃,which could adjust the peak temperature by 0.90% and generate a buffering effect on the inlet temperature.Therefore,the operating temperature range of the three-stage CTS device is wider than that of the single-stage heat-storage unit.In addition,the storage density of the three-stag

关 键 词：梯级储能 ?优化 传热特性 

分 类 号：TK02[动力工程及工程热物理]