考虑分布式煤改电负荷接入的配电网运行调度控制策略研究

大规模的煤改电用负荷的投入对本身薄弱的配电网造成较大的负担。高峰时期用户使用电供暖设备数量持续增加、使用时长逐渐延长,造成局部台区、线路重载及过载运行,给吐鲁番电网安全稳定运行带来了威胁。在考虑“煤改电”负荷接入配电网的网架下,首先,通过调研吐鲁番“煤改电”工程接入模式和设备种类,建立“煤改电”标准化配置模式及产品分类统计;然后,基于电路模拟的等效热参数模型建立运行典型电供暖配置模式下的运行机理模型,研究直接负荷控制技术进行“煤改电”负荷控制。选取吐鲁番市完成“煤改电”工程改造的台区重过载运行进行实例分析,调度控制策略成功将变压器运行在安全边界以内,且不影响用户采暖的热舒适度。     

地板辐射供冷

对国内地板辐射供冷的研究和应用状况进行了简要总结,对地板辐射供冷量、防结露措施、新风与卫生条件、热舒适性等方面进行了介绍.研究结果表明,在一定条件下,地板供冷的使用效果良好.并比较了住宅用冷却地板单独供冷、风机盘管单独供冷及两者联合运行三种供冷方式.     

Comparative studies of the occupants’ behaviour in a university building during winter and summer time

The paper focuses on the assessment of indoor comfort and energy consumption of a university building in Cyprus, during winter and summer of 2012 and 2013. The aim was to make a comparative study of the occupants’ behaviour and its effects on the building's energy consumption, along with the indoor thermal and visual comfort between the two seasons. American Society of Heating, Refrigerating and Air conditioning Standards are used through a questionnaire campaign and the thermal comfort of occupants is analysed with the indicators of predicted mean vote and predicted percentage dissatisfied. The answers are analysed using SPSS software. The air temperature, the relative humidity and the lighting levels of the building are monitored using temperature, humidity and lux meter tools. The monthly energy consumption cost is also calculated. The results are analysed and comparative studies of the occupants’ behaviour conclude to various patterns of effects on the thermal and visual comfort of the building, as well as on its energy consumption.     

用相对热指标和预测平均反应研究火车站热舒适状况

介绍了稳态和过渡空间下室内热舒适性的评价指标,对西安火车站候车厅热环境参数进行了现场测试,并用RWI和PMV．PPD两个指标对测试环境的热舒适性进行分析计算和评价,认为RWI指标更适合评价火车站热舒适。     

影响3D电视图像舒适度的双眼串扰范围研究

本文主要研究了影响立体电视图像舒适度的主要因素,结合5点双眼串扰测试研究双眼串扰对立体电视舒适度的影响。通过30名观看者对具有不同串扰值的立体电视机的主观测试及实验数据分析,给出了影响3D电视图像舒适度的双眼串扰范围。实验结果对评价3D电视图像舒适度提供了依据,也对今后的研究具有指导意义。     

Chilled ceiling and displacement ventilation aided with personalized evaporative cooler

This paper aims at studying the energy impact of a chilled ceiling displacement ventilation CC/DV system aided with a personalized evaporative cooler (PEC) directed towards the occupant trunk and face. A simulation model is developed for integrating the personalized cooler with the ascending thermal plume. The thermal model of the conditioned room air around the person is integrated with a segmental bioheat and thermal comfort model to predict the human thermal comfort.The model is validated with experimental data on the vertical temperature distribution in the room, and the recorded overall comfort perceived by surveyed subjects. Experimental results agreed well with predicted values of temperature and comfort level. When using personalized cooling, the DV supply air temperature can be as high as 24 °C while the PEC at flow rates of 3–10 l/s achieved similar comfort with a DV system at supply temperature of 21 °C. At equal thermal comfort level, the integrated CC/DV system, PEC model resulted in up to 17.5% energy savings compared to the CC/DV system without a PEC. When mixed air is used in the CC/DV system additional 25% savings in energy is realized when compared with energy used for the 100% fresh air without the PEC.     

Free-running temperature and potential for free cooling by ventilation: A case study

Free-cooling by ventilation is one of the most energy efficient techniques for cooling. When ventilation is used for cooling, variable airflow rates should to be used in order to achieve comfortable room temperatures and to minimize the energy demand for mechanical ventilation. Thus, free-cooling, requires, obviously, the existence of a potential for cooling and needs control mechanisms for the airflow. In this study, the free cooling potential by ventilation for office buildings is evaluated by the free-running temperature. The free-running temperature approach is based on the energy balance of heat gains and losses. It is adapted to evaluate the potential for free cooling by ventilation of office buildings for which the gains through the walls are negligible as compared to the internal and solar gains. The free-running temperature of each office room considers solar and internal heat gains, outdoor temperature, indoor temperatures and ventilation air flow rates. The approach is applied to 14 office rooms in a passively cooled office building in Germany and is used to estimate the potential and to evaluate the total energy saving by free cooling by ventilation. The good fit between monitoring data and calculation procedure proves that the free cooling potential can be accurately estimated by using the difference between the comfort limits, i.e. the target value of the indoor temperature, and the free-running temperature.     

Experimental investigation and theoretical analysis of solar heating and humidification system with desiccant rotor

In this paper, a solar heating system, which combines the technologies of evacuated tube solar air collector and rotary desiccant humidification together, has been configured, tested and modeled. The system mainly includes 15 m² solar air collectors and a desiccant air-conditioning unit. Two operation modes are designed, namely, direct solar heating mode and solar heating with desiccant humidification mode. Performance model of the system has been created in TRNSYS. The objective of this paper is to check the applicability of solar heating and evaluate the feasibility and potential of desiccant humidification for improving indoor thermal comfort. Experimental results show that the solar heating system can convert about 50% of the received solar radiation for space heating on a sunny day in winter and increases indoor temperature by about 10 °C. Compared with direct solar heating mode, solar heating with desiccant humidification can increase the fraction of the time within comfort region from about 10% to 20% for standalone solar heating and from about 30% to 60% for solar heating with auxiliary heater according to seasonal analysis. It is confirmed that solar heating with desiccant humidification is promising and worthwhile being applied to improving indoor thermal comfort in heating season.     

Solar control: A general method for modelling of solar gains through complex facades in building simulation programs

This paper describes a new general method for building simulation programs which is intended to be used for the modelling of complex facades. The term ‘complex facades’ is used to designate facades with venetian blinds, prismatic layers, light re-directing surfaces, etc. In all these cases, the facade properties have a complex angular dependence. In addition to this, such facades very often have non-airtight layers and/or imperfect components (e.g. non-ideal sharp edges, non-flat surfaces, …). Therefore building planners often had to neglect some of the innovative features and to use ‘work-arounds’ in order to approximate the properties of complex facades in building simulation programs. A well-defined methodology for these cases was missing. This paper presents such a general methodology.The main advantage of the new method is that it only uses measureable quantities of the transparent or translucent part of the facade as a whole. This is the main difference in comparison with state of the art modelling based on the characteristics of the individual subcomponents, which is often impossible due to non-existing heat- and/or light-transfer models within the complex facade.It is shown that the new method can significantly increase the accuracy of heating/cooling loads and room temperatures.     

Effects of wallboard design parameters on the thermal storage in buildings

The phase change material (PCM) could be added to the wallboard to increase the thermal mass to decrease in indoor temperature fluctuation and improve thermal comfort. In this study, experimentally validated simulation was performed to investigate the effects of various parameters of PCM including the nominal average phase change temperature, its range, the convective heat transfer coefficients and the wallboard thickness on the thermal storage performance of the wallboard such as the thermal energy storage and the time shift.It was found that the average phase change temperature should be close to the average room temperature to maximize the thermal heat storage in the wallboards. The phase change temperature should be narrow to maximize the thermal heat storage in the PCM wallboards. The thermal heat storage increased with the convective heat transfer coefficient, and the optimal average phase change temperature to maximize the storage shifted a bit to a higher temperature with it. The time shift was found to decrease with the convective heat transfer coefficient and the phase change temperature range.