TRNSYS simulation for solar-assisted liquid desiccant evaporative cooling

ABSTRACT

Recently, desiccant cooling systems are well thought of as a competent method for controlling the water content in the air. A solar flat-plate collector has been used as it decreases the dependency on non-renewable resources. Solar-aided liquid desiccant systems have been used to reduce the dependency of air-conditioning systems on non-renewable sources of energy. Manipal’s humid and searing climate provides certain benefits in setting up such a system. The suggested system has reliability and equipment life and also takes complete advantage of the available solar energy for the renewal of the liquid desiccant. TRNSYS simulation is used to predict the efficiency and feasibility of the system. The temperature and energy-load variations were successfully obtained. An effective simulation was developed whereby the solar air conditioning of a room was indicated.     

Particle swarm optimization for AC-coupling stand alone hybrid power systems

The main purpose of this study was to present a technique on how to optimize the configuration of a typical AC-coupling stand alone hybrid power system (SAHPS). The design was posed as an optimization problem whose solution allowed obtaining the configuration of the SAHPS that minimized the total cost through the useful life of the system. To verify the system component models, an existing PV/wind/diesel hybrid power system at Chik Island, Thailand, was selected as a reference system, and the in situ monitoring results were compared with the simulation results. The minimization of the objective function was evaluated using TRNSYS 16 in assistance with GenOpt (optimization program). The result showed that the overall best cost reduction has been achieved by the particle swarm optimization (PSO) with constriction coefficient algorithm. This method requires just a few seconds to give the best results (where the number of generations in the algorithm is 46). It is thus believed that the present method would decrease the time required by design engineers to find the SAHPS optimum solution.     

PV Analyst: Coupling ArcGIS with TRNSYS to assess distributed photovoltaic potential in urban areas

This study presents a means to extend the functionality of Geographic Information Systems (GIS) in assessing distributed photovoltaic (PV) potential in urban areas, via the new ArcGIS extension: PV Analyst. A methodology is proposed for coupling ArcGIS with TRNSYS that enables the PV Analyst extension to use the capabilities of 4 and 5-parameter PV array performance models and the irradiance components in TRNSYS for solar energy simulations in geospatial contexts. Because PV Analyst is embedded within the ArcMap environment, part of ArcGIS software package, the strong capabilities of ArcGIS and other ArcGIS extensions such as 3D Analyst, Spatial Analyst and Tracking Analyst can be fully utilized with PV Analyst’s functionalities. This paper describes the concept and details of the extension development, as well as its application to the Pollock Commons area at the Pennsylvania State University.     

太阳能低温地板辐射采暖的TRNSYS模拟研究

利用TRNSYS对兰州地区的气象资料进行模拟分析,通过对建筑外围护结构的节能设计和低温地板辐射采暖的热舒适性研究以及兰州地区太阳辐射的特点探讨了太阳能与低温地板辐射采暖的互补优势,充分发挥建筑节能的特点。     

不同岩土热物性参数测试方法的比对试验研究

岩土热物性参数以及如何准确获得岩土体热物性参数的方法对整个地埋管地源热泵系统的设计至关重要。本文通过对一个实际应用的地源热泵系统的研究,采用两种测试方法进行测试分析对比;使用瞬时系统模拟软件TRNSYS建立理论分析模型,基于不同的热物性参数测试方法对地源热泵系统设计进行分析,指出两种测试方法的偏差和优缺点,为地埋管地源热泵工程设计及施工提供依据。     

Comparison of annual energy performances with different ventilation methods for cooling

Stratum ventilation has been proposed to cope for elevated indoor temperatures recommended by governments in East Asia. TRNSYS is used for computation of the space cooling load and system energy consumption. Typical configurations of an office, a classroom and a retail shop in Hong Kong are investigated. Compared with mixing ventilation and displacement ventilation, stratum ventilation derives its energy saving potential largely from the following three factors: the reduction in ventilation and transmission loads and increased COP of chillers. The year-round energy saving is found to be substantial at 25% and 44% at least when compared with displacement ventilation and mixing ventilation, respectively.     

新型混合地源热泵的土壤热平衡性能模拟

地源热泵是一种新型节能环保的绿色能源利用技术,在应用过程中,存在的较大问题之一就是对土壤的吸放热不平衡。针对此问题本文提出了一种新的混合地源热泵形式,将热水系统和地源热泵空调系统进行耦合,对长沙某宾馆进行了系统设计并用TRNSYS进行了长达30年的模拟。通过和传统单一的地源热泵空调系统比较,证实了该系统不仅能有效地解决土壤吸放热不平衡问题,而且有效地提高了机组的运行效率。     

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.     

Multi-turbine wind-solar hybrid system

In the paper, a new type of wind-solar hybrid system was proposed, in which multiple small wind turbines took the place of a bigger one. The electricity performance of the multi-turbine wind-solar hybrid system was studied in comparison with the traditional system. Two types of wind-solar hybrid system with the same capacity were set up in Tianjin, and the power output of the two systems were measured and simulated by the TRNSYS software. The results showed that, at low wind speed, the multi-turbine wind-solar hybrid system has more power production than the reference system. The simulated results agreed well with the experiment results. Then, the electricity performance of the multi-turbine wind-solar hybrid system was studied under various climates in China by the TRNSYS. The simulation results showed that the power output of the wind turbines in multi-turbine wind-solar hybrid system increases by 18.69%, 31.24% and 53.79%, when used in Shenyang, shanghai and Guangzhou, respectively, compared with the reference system.