Efficiency analysis of a solar photovoltaic array coupled with an electrolyser power unit: a case study

Hydrogen as an energy carrier is one of the most potential candidates for clean energy and can be produced by water electrolysis. The use of 10?kW photovoltaic arrays for supplying a 5?kW electrolyser which consists of 10 series-connected electrolyser stacks and a 28% alkaline (KOH) solution electrolyte has been investigated at the Taleghan renewable energies site in Iran. The hydrogen produced by the electrolyser provides energy for the 1?kW polymer electrolyte membrane fuel cell, which meets the load when the solar energy is insufficient. Variations of the solar radiation intensity, the hydrogen production rate, the solar hydrogen efficiency and the overall efficiency of the solar hydrogen energy unit were monitored in detail. The overall energy efficiency was found to range from 0.93% to 5.01%. The obtained results demonstrate the great potential of such a power system for producing and storing energy in a solar-belt country like Iran.     

冷热电联产系统性能评价指标研究

根据冷热电联产系统的供能特点,在比较分析联产系统性能评价指标的基础上,提出了用当量电效率来评价联产系统的性能的方法.文章用一次能源利用率、(火用)效率和当量电效率对冷热电联产系统的性能进行了分析,结果表明当量电效率具有合理、可行性和简单实用的特点.     

太阳能光伏发电在绿色建筑中的有效利用

针对目前制约太阳能光伏产业发展的重要因素——光伏发电的效率过低、成本过高问题,提出了一种太阳能光伏发电与建筑排风相结合的新型绿色建筑形式。在光伏发电系统设计合理的前提下,对不同类型的建筑以及在不同环境下使用太阳能发电来提高发电效率的情况进行分析,可知其产生的经济性效益有明显差别。结合工程实例,理论分析了太阳能发电在绿色建筑中的有效合理利用,并得出结论。     

Study on the performance of a solar assisted air source heat pump system for building heating

This paper proposed a new solar assisted air source heat pump system with flexible operational modes to improve the performance of the heating system. A mathematical model was established on the solar assisted air source heat pump system for building heating with a heating capacity of 10 kW, and an air source heat pump unit was developed to validate the model. The effect of the solar collector area on the performance of the system running in Nanjing was studied. The results showed that the COP of the heat pump unit was enhanced with the increase of the solar radiation density during the typical sunny day in the heating season. In addition, the COP also increased in proportion to the solar collector area. Compared with the case when the solar collector area was 0 m², the COP increase of the heat pump and the energy-saving rate were 11.22% and 24% respectively when the solar collector area was 40 m². Meanwhile, the solar equivalent generation power efficiency could reach 11.8%.     

Temperature of a photovoltaic module under the influence of different environmental conditions – experimental investigation

The climate changes affect photovoltaic (PV) module temperature significantly. The module temperature is one of the most important factors that influence the PV module efficiency and a deep analysis of PV module temperature will aid in better understanding of the environmental influences on the PV module performance. The module temperature depends on many parameters such as solar radiation, ambient temperature, air humidity, speed and direction of the wind, PV module orientation, dust and sand deposition on PV module, and PV module materials. An experimental research was conducted to investigate the effect of these factors on the PV module temperature in the Renewable Energy Laboratory of the Graduate University of Advanced Technology in Iran. The results of this study highlighted that the deposited dust over the PV module surface increases the module temperature and this consequently decreases the PV module power. It was also revealed that a combination of the temperature increase and the incident solar radiation decrease due to the dust deposition over the PV module enhances significantly the module power reduction.     

Comparison of solar radiation data sources for design and performance appraisal of CSP systems in India

The choice of a solar radiation data source is expected to have a significant impact on the predicted performance of a concentrating solar power (CSP) system and consequently on its technical and financial feasibility. In the present study, an attempt has been made to analyse the effect of choice of various solar radiation data sources on the predicted performance of a CSP system at 13 different locations in 5 different climatic zones of India. It was observed that there is significant variation in the amount of annual electricity output obtained for various locations using different solar radiation data sources resulting in variations in levelised cost of electricity. For a 50-MW parabolic trough-based CSP plant located in Jaisalmer, the estimated value of annual electricity output varies from 63 to 124?GWh. For a CSP plant based on the central tower receiver technology, the corresponding range is from 106 to 145?GWh.     

太阳能热泵区域性设计

通过分析不同地区的太阳能资源季节分布以及室外气温等气候参数之间的对应关系,将气候分区的概念引入太阳能热泵系统设计中。根据全国各地的气候特点,将全国划分为4个不同的区域,提出可使用4种不同类型的热泵系统,并分别给出其适用区域。提出一种储热型多功能太阳能热泵系统作为例子,分析其在不同条件下的运行模式,结果表明其可适用于不同地区和季节及用户的需要。     

风光互补发电系统在工程中应用的可行性分析

根据烟台市的风能太阳能资源条件,考虑到风能太阳能发电的互补特性,将风力发电装置和光伏发电装置组合成风光复合发电系统,分析了该复合系统的结构组成及原理,研究结果表明：该系统能够满足负载对用电量的要求,经济性较好,在解决偏远的高速公路路灯以及孤岛等的供电问题上提供了新的解决方式。     

长方体建筑屋顶风能利用效能研究

屋顶安装小型风力发电机是近几年来新发展的一种风能利用形式。以年平均风速为对象,研究建筑屋顶风能利用的效能,提出衡量建筑风能利用效能的6个性能指标。利用CFD数值模拟方法分析了长方体建筑平屋顶对风能的利用效果,考察了不同迎风角下控制点的性能指标,探讨屋顶风力机安装的最佳位置和排列形式。对长方体建筑屋顶形式进行分析,对比了4种不同屋顶形式的风能利用效能。     

青岛热泵辅助太阳能供热系统的性能分析

结合工程实例,对热泵辅助太阳能供热系统的流程进行了分析。对不同朝向、倾角平板集热器的表面太阳辐照度、太阳能热水系统热效率、空气源热泵制热性能系数进行了实测及计算。对于青岛地区,平板集热器宜采取朝南安装、倾角为45°。     

Optimising the tilt angle for solar surfaces using different solar irradiation models in Yazd,Iran

This paper deals with the determination of the optimum tilt angle for south-facing solar surfaces to collect the maximum solar irradiation in Yazd, Iran. In order to increase the accuracy of results, different models are used in this study. The accuracy of the models is compared in terms of the statistical indicators, RMSE and MBE. The results indicate that the Klucher model gives the best results for estimating the solar radiation reaching the solar surfaces. In comparison to the horizontal surface, on average the gain of energy during the year will be 22.82% if a solar surface is installed at yearly optimum tilt angle. For higher efficiency, it is suggested that the solar surface mounts at the seasonal tilt angle. This leads to an increase in the efficiency of the solar surface of more than 8.86% over that of a similar fixed solar surface at the annual tilt angle.     

Finite element model updating of a large structure using multi-setup stochastic subspace identification method and bees optimization algorithm

In the present contribution, operational modal analysis in conjunction with bees optimization algorithm are utilized to update the finite element model of a solar power plant structure. The physical parameters which required to be updated are uncertain parameters including geometry, material properties and boundary conditions of the aforementioned structure. To determine these uncertain parameters, local and global sensitivity analyses are performed to increase the solution accuracy. An objective function is determined using the sum of the squared errors between the natural frequencies calculated by finite element method and operational modal analysis, which is optimized using bees optimization algorithm. The natural frequencies of the solar power plant structure are estimated by multi-setup stochastic subspace identification method which is considered as a strong and efficient method in operational modal analysis. The proposed algorithm is efficiently implemented on the solar power plant structure located in Shahid Chamran university of Ahvaz, Iran, to update parameters of its finite element model. Moreover, computed natural frequencies by numerical method are compared with those of the operational modal analysis. The results indicate that, bees optimization algorithm leads accurate results with fast convergence.     

Solar reflectivity of common building materials and its influence on the roof heat gain of typical southwestern U.S.A. residences

The fraction of incident solar energy reflected by the exterior elements of a structure significantly effects the overall heat gain or loss of the structure. This is particularly true for regions that receive an abundance of solar insolation as occurs in the southwestern part of the United States. However, the available data on the solar reflectivity of common building materials are apparently rather sparse. In order to augment these data, the authors developed a probe for measuring hemispheric solar flux and employed it to measure the solar reflectance of a wide variety of building materials. Results of these measurements are presented and reviewed. The measured reflectivity values have also been used in heat gain/loss computations for typical southwestern residences. Results of some of these computations are presented to demonstrate the change in structure heat gain/loss that can realistically be achieved by altering roof reflectivity.     

Evaluation of existing cooling systems for reducing cooling power consumption

This work was designed to estimate the cooling load power consumption during the summer in the hot and humid areas of Iran. The actual electrical energy consumption for cooling systems of some typical buildings with various applications (3 residential home buildings, 2 industrial plant buildings, a trade center with 38 shops, 3 public sectors and a city hospital) in a hot and humid region in South of Iran was recorded during the peak load period of the year (July–August). The records were used for estimating the total power consumption of the cooling systems in this region. According to this estimation, which was confirmed by the regional electrical power distribution office, the cooling systems power consumption in this region accounted for more than 60% of the total power consumption during the peak load period of the year.     

天津地区太阳能-土壤源复合式热泵系统性能研究

北方某些地区南于冷热负荷的不平衡性,单一的土壤源热泵系统受到限制。太阳能辅助土壤源热泵系统是一种有效利用可再生能源的系统形式。本文对天津地区太阳能辐射情况、建筑全年逐时冷热负荷量及复合热泵系统的制热机组效率进行研究,分析在天津地区太阳能-土壤源复合热泵系统的节能性。     

可持续节能建筑的直流供电架构

针对太阳能、电动汽车及LED照明等新能源技术的出现及其在可持续节能建筑中的应用前景,为了提高可持续节能建筑的电力利用效率和可靠性,进一步降低可持续节能建筑之电力系统的成本和碳足迹,本文提出了在未来的可持续节能建筑中采用直流供电的系统架构取代传统的交流供电架构的概念。     

某太阳能光伏并网发电工程的分析

研究了太阳能光伏发电系统的组成及光伏发电基本原理,简单概述了光伏发电的优点和局限性,结合实例对太阳能光伏发电工程进行了分析,得出现阶段太阳能发电系统可以并网运行,但不能倒送电的结论。     

Decrease in CO2 emission per capita as a result of the reduction in power grid losses in Iran

ABSTRACT

In power grids, a significant amount of the generated power in power plants is wasted in the grid between power plants and consumers. The amount depends on different factors. With regard to the vital role of electricity in economic and social development alongside with high investment costs in electricity generation, transmission and distribution, practical solutions for decreasing grid losses and enhancing the efficiency of existing facilities are crucial. Due to the global environmental situation and significant effects of energy consumption on the environment, the general trend is towards the deployment of methods which are more efficient and less fuel consuming. In addition, more implementation of monitoring and controlling equipment and instalment of more efficient equipment in electricity transmission and distribution sectors reveal the effort towards the reduction of pollutants. These facts reveal the importance of this issue amongst authorities in the power industry. In this research through the assessment of power grid losses and studying different types of power plants in Iran, the amount of electricity generation and grid loss are studied. In addition, the impact of different power plants on the amount of environmental pollutants especially CO₂ is presented. Also, some solutions to reduce CO₂ emission are provided.     

Experimental investigation of a PV solar generator for supplying water treatment process

The paper describes a photovoltaic solar generator to supply a dielectric barrier discharge ozone generator employed for water treatment. This paper reports trials of the equipment and modelling the solar power generation system’s efficiency. The design methodology was used to obtain the optimal set point for the orientation of the solar panel during the passage of clouds which causes the decrease of sunlight and thus reduced ozone production. In Algeria, autumn is characterized by the passage of clouds almost every day which negatively affects the performance of the solar panel. The objective of this paper is to identify the set point and to set the robustness of the process in cloudy weather, by determining the optimal values of the orientation angles (north-south and east-west), in order to maximize the power produced by the solar system. Three ‘centred face-composite’ designs were performed on a laboratory experimental set-up and an optimal point was determined.     

国内外热电联产性能评价指标介绍与分析

介绍了各国常用的热电联产(CHP)系统性能评价指标。我国采用CHP系统综合效率作为评价指标,但综合效率以热力学第一定律为基础,不能完全反映CHP系统的实际性能水平,也没有反映出与热电分产系统的差别。应借鉴国外经验,引入相对一次能耗节约率、相对CO2排放减少率等节能减排指标,修改补充我国CHP系统性能评价指标体系。