冰球式蓄冷槽内冰球冻结和放热特性的数值模拟分析

在冰蓄冷系统中,冰球式蓄冰槽是一种常用的蓄冰设备;通过相变材料的潜热保存冷量。对冰球式蓄冰槽内冰球的冻结和解冻过程进行了数值模拟,通过对比冻结曲线和解冻曲线,探究了冰球不同的排布方式对冰球冻结速率和解冻速率的影响。结果显示:采用顺排方式的蓄冰槽冰球冻结时间为29 400 s,而采用错排方式的蓄冰槽冰球冻结时间为25 200 s,错排方式能够提高冰球在预冷阶段的冷却速率,从而降低冻结时间;在解冻过程中,错排方式融冰相变过程的时间明显小于顺排方式,而融冰后的显热阶段两种排列方式的差异不大。     

Modeling and optimization of a solar assisted heat pump using ice slurry as a latent storage material

This paper presents the modeling and optimization of a solar assisted heat pump using ice slurry. Solar collectors are used as the primary source of thermal energy, with two distinct loops allowing the collectors to operate in series with an ice tank, or a warm water tank. Thermal energy stored in the ice tank is transferred to a warm water distribution tank via a heat pump. First, a new mathematical model of an ice slurry storage tank is presented. Validation of the model with experimental data confirms its ability to predict the ice mass and tank fluid temperatures during the charging and discharging modes of operation. The developed ice tank model is combined with the TRNSYS energy simulation program to formulate a complete model of the proposed heat pump system. This computer model then serves as a base for a mathematical optimization with the objective to minimize the energy use for heating and DHW over a single heating season. Simulated results demonstrate the potential of the optimized system in reducing the heating operating energy use of a high performance home in Montreal, QC.     

管内融冰式冰蓄冷空调系统的动态仿真

在已建立的空调系统水侧仿真平台上，增加了采用阻容网络方法建立的内融冰式蓄冰槽的半动态模型，搭建了冰蓄冷系统水侧仿真器。利用仿真器模拟了冰蓄冷系统的五种运动模式，并进行了分析和研究，为冰蓄冷系统优化控制的研究提供了试验基础。     

Experimental characteristics of a storage tank on a harvest-type ice storage system

This paper is concerned with the development of a new method for making and separating ice and saving floated ice by installing an evaporation plate at underwater within a storage tank. In a conventional harvest-type ice storage system, a tank saves ice by separating a formed ice from an installed evaporation plate, which is located above an ice storage tank as an ice storage system. A new harvest-type method shows better heat transfer efficiency than a convectional method. It is because the evaporation panel is directly contacted with water in a storage tank. Also, at a conventional system a circulating pump, a circulating water distributor and a piping are installed, but these components are not necessary in a new method. In this study two kinds of ice storage systems are experimentally investigated to study the thermal characteristics of ice storage tanks. The results show the applicable possibility and performance enhancement of a new type.     

Numerical Study of Convection Melting Inside Ice Storage Systems by the Lattice Boltzmann Model

Abstract

The internal melt ice-on-coil tank with horizontal pipes is widely used in ice storage systems. The tank’s discharge process is greatly affected by the natural convection process that is caused by melting of the phase change material outside the pipes. To achieve an optimal arrangement of the pipes, a double-population lattice Boltzmann model was developed to simulate the transient solid-liquid phase change behavior in a section of an internal-melt ice-on-coil thermal storage tank with nine aligned built-in horizontal pipes. The evolutions in the phase change interface and melting rate was illustrated with different pipe shapes and pipe connections. Based on the melting rate, the whole melting process was divided into three stages: sharp decrease stage, continuous decrease stage, and snail-melting stage. The numerical results showed that a high melting rate was obtained by preferentially assigning the high-temperature pipes to the upper part of the tank, while a stable melting rate could be obtained when high-temperature pipes were preferentially assigned to the bottom part of the tank.     

盘管式外融冰槽融冰过程试验研究（I）——取冷特性

作者在搭建的50RTH(1RTH=3517W·h)盘管式外融冰实验台上研究了外融冰取冷的动态过程,全面考察了取冷进出口模式、取冷流量、入口温度、初始蓄冰量、搭接等因素对冰槽取冷特性的影响。研究结果表明:1)取冷进出口模式严重影响冰槽取冷特性:不同进出口模式下取冷出口水温的变化过程有很大差异;在取冷的前4/5时间,下进模式取冷的出口温度比上进模式低2 5℃;2)取冷流量对于出口水温的影响小于1℃;3)恒定流量条件下,入口温度的变化会较大程度影响到取冷速率的变化,而对出口水温的影响小于0 5℃;4)初始蓄冰量对于取冷特性影响很小;5)冰柱搭接急剧提高取冷出口温度。     

储冰桶换热管组流动特性研究

分析了储冰桶换热器管组的流动过程,建立实际流动的物理模型,通过理论推导,获得了分析解。为准确计算换热器组流量分布,系统压降以及设计提供了一种理论方法。     

Performance evaluation of a new ice preservation system for supermarkets

At present, all types of large–medium‐sized supermarkets with aquatic products adopt ice preservation to ensure freshness. The traditional method of ice preservation needs to make a large amount of thick ice and thus wastes manpower and freshwater. A new ice preservation system with cold storage (IP&CS) is designed, and its performance is tested. The use of a cold storage tank to replace the thick ice laid achieves a repeated cold storage and discharge. This experiment uses NaCl solution as the cold storage phase change material (PCM). The phase change temperature of the cold storage PCM and the optimum temperature of the secondary refrigerant during the cold storage process are determined. Results show that the center temperature of aquatic products, water loss rate, color of aquatic products, power consumption, and electricity cost of the IP&CS system are better than those of the traditional ice preservation system.     

Fundamental study of the melting process of crushed ice in a heat storage container

This report deals with heat transfer in the melting process of crushed ice filling an ice/water heat storage container. The volumetric heat transfer rate and melting end-times are measured for the cases when rectangular-type, small-stone-type, and particle-type ice in the container are melted using circulating warm water. The melting end-time is shortest for small-stone-type ice and longest for particle-type ice. The volumetric heat transfer rate is greater for small-stone-type ice and rectangular-type ice than for particle-type ice. The flow rate of the circulating warm water fed into the tank from an inlet pipe has a major effect on the heat transfer rate. © 1999 Scripta Technica, Heat Trans Asian Res, 28(7): 583–596, 1999     

冰蓄冷空调蓄冰罐特性的研究

本文通过对某大厦冰蓄冷空调系统的运行情况的测试,详细研究和分析了蓄冰罐在不同流量下的蓄冷和释冷特性,在融冰工况时,蓄冰罐进口温度出口温度和释冷量的影响。     

直接蒸发式盘管外蓄冰机理的试验研究

直接蒸发式盘管管外蓄冰效率比间接媒的管外蓄冰要高,本文主要针对在蓄冷罐中蒸发式盘管管外蓄冰的机理进行试验研究,得出蓄冰量以及水的初始温度随时间的变化规律。     

某供电大楼冰蓄冷空调测试的分析与评估

通过实测、调研某供电大楼冰蓄冷空调系统,从技术和优化运行角度对该冰蓄冷空调系统所测数据进行分析,指出该系统中蓄冰槽蓄冷率低、释冷不足的问题,并进行分析。接着论述了冰蓄冷空调系统的蓄冰槽不仅要在蓄冰量上与系统主机容量相匹配,同时还要考虑到蓄冰槽的蓄冰、融冰特性,最后说明系统运行管理人员对冰蓄冷空调系统在节能运行上产生的影响。     

Energy and exergy analyses of an ice-on-coil thermal energy storage system

In this study, energy and exergy analyses are carried out for the charging period of an ice-on-coil thermal energy storage system. The present model is developed using a thermal resistance network technique. First, the time-dependent variations of the predicted total stored energy, mass of ice, and outlet temperature of the heat transfer fluid from a storage tank are compared with the experimental data. Afterward, performance of an ice-on-coil type latent heat thermal energy storage system is investigated for several working and design parameters. The results of a comparative study are presented in terms of the variations of the heat transfer rate, total stored energy, dimensionless energetic/exergetic effectiveness and energy/exergy efficiency. The results indicate that working and design parameters of the ice-on-coil thermal storage tank should be determined by considering both energetic and exergetic behavior of the system. For the current parameters, storage capacity and energy efficiency of the system increases with decreasing the inlet temperature of the heat transfer fluid and increasing the length of the tube. Besides, the exergy efficiency increases with increasing the inlet temperature of the heat transfer fluid and increasing the length of the tube.     

Determining correlations between final hydrogen temperature and refueling parameters from experimental and numerical data

During the hydrogen filling process, the excessive temperature rise may cause the hydrogen storage tank to fail. Therefore, preventing the temperature from rising too high is an important guarantee for the safety of the hydrogen storage cylinder. The analytical solution of a single-zone thermodynamic model for hydrogen refueling is obtained. Based on the analytical solution of the final hydrogen temperature derived from the hydrogen filling theoretical model, the relationship among the final hydrogen temperature and the initial temperature and the inlet temperature and the ambient temperature is obtained. The model is used to achieve correlations coefficients among the above parameters. Data of Type III 40L tank and Type IV 29L tank used in the model are from the experiment, and data of Type III 25L tank and Type IV 174L tank are from the simulation. The results show that our analytical solution is applicable for determining correlations between final hydrogen temperature and refueling parameters from experimental and numerical data. Our analytical solution is more accurate than the reduced model reported in reference. At the same time, the effects of the initial temperature and the inlet temperature on the final temperature are stronger in Type IV tank than in the Type III tank. This study may provide guides for improving hydrogen refueling standards.     

Thermodynamic modeling of hydrogen fueling process from high-pressure storage tank to vehicle tank

This study develops a hydrogen fueling station (HFS) thermodynamic model that simulates the actual fueling process in which hydrogen is supplied from a high-pressure (HP) storage tank into a fuel cell electric vehicle (FCEV) tank. To make the model as accurate as possible, we use the same components and specifications as in actual HFSs, such as a pressure control valve, a pre-cooling system, and an FCEV tank. After the components and their specifications are set, pressure and temperature profiles are set as the HP tank supply conditions. Based on the pressure and temperature profiles, the model solves for the temperature, pressure, and mass flow rate of hydrogen at each downstream position, including the inside of the vehicle tank. The values predicted by the model are compared with experimental data, and we show that the developed model makes it possible to accurately simulate those values at any position during the fueling process.     

冰盘管蓄冰过程的动态特性

建立了直接蒸发过程冰盘管的动态模型，并对模型进行求解，得到冰盘管的结冰半径、热流密度以及蓄冷量随时间变化的关系。该模型能较好的反映冰盘管的动态特性。     

应用于平抑风功率的燃氢燃气轮机储能系统控制策略研究

储能技术可用于提高风电并网能力,因此其储能系统及控制策略成为研究热点。提出将燃氢燃气轮机作为储能系统主要部分,低通滤波器结合模糊控制作为其平抑风功率的控制策略。通过设定储氢罐容量,对15台1.5 MW风机的历史风功率数据进行了处理。结果表明：低通滤波器结合模糊控制能有效平抑风功率至限制值,实现平抑指标,并得到储氢罐容量的设置限制;可实现储能时燃气轮机不工作,耗能时燃气轮机工作,当储氢罐容量为0.017 m³时,燃气轮机输出功率为0.1 MW。在将燃气轮机作为平抑风功率的储能系统时,需将燃气轮机的启停控制作为今后的研究重点。     

蓄冰槽盘管不完全冻结式内融冰与外融冰的取冷特性实验

为更有效地利用冰蓄冷的低温冷源，实验比较了不完全冻结式内融冰取冷特性与无扰动外融冰及鼓气作用下外融冰的取冷特性。结果表明，鼓气作用下的外融冰具有最佳的融冰释冷特性，出水温度低，取冷速率稳定，蓄冰槽的能量利用率明显提高。     

Numerical simulation of the hydrogen storage with reaction heat recovery using metal hydride in the totalized hydrogen energy utilization system

Numerical simulation of a hydrogen storage tank of a Totalized Hydrogen Energy Utilization System (THEUS) for application to commercial buildings was done to verify the practicality of THEUS. THEUS consists of a fuel cell, water electrolyzer, hydrogen storage tank and their auxiliary machinery. The hydrogen storage tanks with metal hydrides for load leveling have been previously experimentally investigated as an important element of THEUS. A hydrogen storage tank with 50 kg AB5 type metal hydride was assembled to investigate the hydrogen-absorbing/desorbing process, which is exothermic/endothermic process. The goal of this tank is to recover the cold heat of the endothermic process for air conditioning, and thus improve the efficiency of THEUS. To verify the practical effectiveness of this improved system, we developed a numerical simulation code of hydrogen storage tank with metal hydride. The code was validated by comparing its results with experimental results. In this code the specific heat value of the upper and lower flanges of the hydrogen storage tank was adjusted to be equal to the thermal capacity of the entire tank. The simulation results reproduce well the experimental results.     

基于内涝防治目标的雨水调蓄池设计

雨水调蓄池是内涝防治的重要措施之一,具有易于推广、工程经济的特点.在现有雨水调蓄池研究的基础上,利用SWMM模型建立淮安市某研究区雨洪模型,通过调整雨水调蓄池各项参数和改变布设位置,分析研究区溢流的结果变化,从而对调蓄池的分散设计策略和容积确定进行研究.结果表明,布设调蓄池前,全区溢流量8 190 m3,最大节点溢流量...