太阳能驱动闭式转轮除湿空调系统性能研究

为解决传统开式转轮除湿空调系统再生排风能量浪费的问题,本文提出了可高效回收再生排风空气显热和潜热的太阳能驱动闭式转轮除湿空调系统,利用TRNSYS软件对系统进行建模,模拟研究了冷水流量比和新风比对系统性能的影响和系统动态性能,并对模拟的准确性进行实验验证。结果表明：模拟结果与实验结果的相对误差最大为±9.8 %。太阳能驱动闭式转轮除湿空调系统的最优冷水流量比为1：5：4。系统在广州地区整个制冷季（6月1日—9月30日）平均电力COPe为2.4,平均热力COPth为2.1,累计取水量为25.66 t,热回收量为9.70 MW。相比于太阳能驱动开式转轮除湿空调系统,太阳能驱动闭式转轮除湿空调系统平均COPe和COPth分别提高42.1%和69.2%,二氧化碳排放量减少29.3%。     

Development of a multicriteria tool for optimizing the renovation of buildings

The renovation of a building involves not just the fulfilment of functional requirements, but also considerations such as energy consumption, investment costs, environmental impact and wellbeing. As things stand, new design methods and tools are needed, and the aim of the research presented in this article was to develop a multicriteria tool, MultiOpt, for the optimization of renovation operations, with an emphasis on building envelopes, heating and cooling loads and control strategies. MultiOpt is based on existing assessment software and methods: it uses a genetic algorithm (NSGA-II) coupled to TRNSYS, and economic and environmental databases. This article illustrates its utilization in the renovation of a school in the southern French city of Nice which was representative of France’s building stock. The study started with the monocriterion optimization of energy consumption, cost, thermal comfort, and life-cycle environmental impact. It then moved onto multicriteria optimizations. The monocriterion analyses focussed on the building’s characteristics and performance; the multicriteria analyses were concerned with the interactions between the different objectives, and with identifying their convergences and divergences. The results demonstrated that MultiOpt can be used to compare different combinations of options and constraints, thus constituting a basis for operational decision-making.     

Influence of pumping head, insolation and PV array size on PV water pumping system performance

A transient simulation model, using TRNSYS, for AC photovoltaic (PV) water pumping systems is developed and validated against laboratory and field data. Simulations and analysis were undertaken in this work to: (i) discern the influence of mismatch of pump characteristics and well system characteristics on system performance; (ii) obtain average efficiencies and average performance ratios for system, subsystem and PV array over any period of time and under different operating conditions; (iii) analyze the effect of insolation frequency distribution on system performance and (iv) determining the optimum PV array size considering life cycle cost analyses. Simulation and analyses are illustrated using a real case study and utilizing real field data obtained from a system installed in Jordan.     

Numerical model and experimental validation of heat storage with phase change materials

This paper describes the numeric model developed to simulate heat transfer in phase change materials (PCM) plunged in water tank storage. This model, based on the enthalpy approach, takes into account the conduction and the convection into PCM as well as at the interface between PCM and water of the storage. Furthermore, hysterisis and subcooling are also included. This model has been implemented in an existing TRNSYS type of water tank storage. It allows the simulation of a water storage tank filled with PCM modules made of different materials and different shapes such as cylinders, plates or spheres bed. Comparisons between measurements and simulations has been undertake to evaluate the potential of this model.     

Dynamical building simulation: A low order model for thermal bridges losses

Thermal bridges losses represent an increasing part of heat losses owing to significant three-dimensional heat transfer characteristics in modern buildings, but one-dimensional models are used in most simulation software for thermal analyses to simplify the calculations.State model reduction techniques were used to develop low-order three-dimensional heat transfer model for additional losses of thermal bridges, which is efficient and accuracy. Coupling this technique with traditional one-dimensional model for walls losses, it is possible to reduce a large amount of time simulations.Low-order model was validated from frequency response and time-domain output. And the effect of this model was shown with its implementation in software “TRNSYS”.     

土壤源热泵变流量系统的长期运行特性研究

在TRNSYS仿真模拟软件的基础上,对其中的变速泵模拟进行了优化,并用实验值验证模型。分别建立定流量和变流量系统的仿真模型,并进行长期模拟。模拟结果得到15年的水泵、热泵机组全年的能耗,分别讨论了制冷期、制热期的能耗情况,并从15年的土壤平均温度变化讨论定流量与变流量对埋管区域热环境的影响。     

土壤源热泵系统建模及运行参数优化

地埋管换热器的优越性能在当今社会越来越受到重视,在供暖、烘干、能源互补利用方面有广阔的前景。本文基于TRNSYS软件建立上海某建筑的模型系统设计,并介绍了建筑负荷模拟的过程、冷却塔串联和并联方式的模拟计算。针对上海的天气情况、土壤源温度的变化作为原始变量进行了模拟分析,比较得出性能好方案,最后进行较好方案的继续优化。     

太阳能辅助燃煤发电系统变工况动态特性分析

针对某600 MW亚临界机组太阳能辅助燃煤发电系统,选择夏至日全天100%THA、75%THA、50%THA3个运行工况,使用TRNSYS瞬态模拟软件,在太阳辐射日变化的条件下,对接入太阳能辅助燃煤发电系统后机组运行的动态特性进行了模拟。结果显示,不同工况下太阳能辅助燃煤发电系统的运行受到太阳能辐照波动的影响,变工况下的系统主要参数变化与流量变化密切相关,太阳能系统运行时锅炉主蒸汽温度升高,烟温降低,压力降低,负荷越低光电转化效率越低。在变工况过程中太阳能接入锅炉会造成主汽温度的升高,必须采取动态喷水减温措施控制主蒸汽温度,维持太阳能侧和锅炉侧的换热平衡。     

基于TRNSYS模拟的户式地源热泵运行特性分析

运用TRNSYS软件搭建了农村住宅和户式地源热泵系统模型,模拟了农村住宅全年的负荷变化情况,分析了不同使用方式下土壤温度的变化情况,不同室外气温和室内设定温度地埋管出水温度和热泵机组的COP以及能耗变化情况。结果表明,夏季使用与不使用相比系统运行10年后土壤体的温度下降0.71 ℃,COP降低0.3%,用电功率提高0.4%;随着室设定温度的提高系统的COP变化不大,供回水温度略有降低,设定温度每提升1 ℃,用电功率提高6%,为户式地源热泵系统的运行提供指导。