建筑南窗遮阳及设计分析研究

一前言被动式采暖太阳房是我国最成熟、应用范围最广、产业化发展最快的太阳能建筑技术之一。被动式太阳能供暖系统根据各地区气象条件,基本上不添置附加设备,只依靠建筑物本身的构造和材料的热工性能,使房屋尽可能多的吸收和贮存热量,以     

Solar optical materials for innovative window design

New and innovative optical materials and coatings can greatly improve the efficiency of window energy systems. These potential materials and coatings increase energy efficiency by reducing radiative losses in the infrared, or reducing visible reflection losses or controlling overheating due to solar gain. Current progress in heat mirror coatings for glass a polymeric substrates is presented. Highly doped semiconducting oxides and metal/dielectric interference coatings are reviewed. Physical and optical properties are outlined for antireflection films and transparent aerogel insulation media. The potential for optical switching films as window elements includes discussions of electrochromic, photochromic and other physical switching processes.     

Glazing and its influence on building energy behavior

The parameters handled when designing a building serve to shape its orientation and characteristics of the envelope elements [Turiel et al. (1984) Energy and Buildings6, 70], and so they can and should be analysed. In the present study one of these parameters will be analysed individually—the glass areas—in a commercial base building. Three different types of glazing have been taken into account: (i) colorless, (ii) bronze colored and (iii) reflectant, insulating with a gap of variable thickness, and single. Energy consumptions in summer and winter have been obtained from these studies.     

An optimum design on the triple‐glazed exhaust airflow window

The flow and heat transfer characteristics of a triple‐glazed exhaust airflow window system were studied numerically by using the finite‐volume method. Exhaust airflow rate, solar insolation and aspect ratio were considered important parameters. It was shown that space‐heat gain was reduced considerably by increasing the exhaust airflow rate. The optimum exhaust airflow rate and aspect ratio were suggested to be Re=600 and W/H=0.05, respectively. Some comparisons between the airflow window system and the enclosed window system were made qualitatively and quantitatively. Copyright © 2002 John Wiley & Sons, Ltd.     

多孔介质-双层玻璃幕墙传热与流动特性

基于多孔介质具有吸收和贮存太阳能的特点,在双层玻璃幕墙通道内设置了多孔介质层,利用多孔介质充分收集与贮存太阳能用于建筑供暖,并采用数值模拟法研究了幕墙的传热与流动特性.结果表明,玻璃幕墙能充分利用太阳能加热新风供暖,集热效率高又节能,有推广价值.     

Evaluation of control strategies for different smart window combinations using computer simulations

Several studies have shown that the use of switchable windows could lower the energy consumption of buildings. Since the main function of windows is to provide daylight and visual contact with the external world, high visible transmittance is needed. From an energy perspective it is always best to have the windows in their low-transparent state whenever there are cooling needs, but this is generally not preferable from a daylight and visual contact point of view. Therefore a control system, which can be based on user presence, is needed in connection with switchable windows. In this study the heating and cooling needs of the building, using different control mechanisms were evaluated. This was done for different locations and for different combinations of switchable windows, using electrochromic glazing in combination with either low-e or solar control glazing. Four control mechanisms were investigated; one that only optimizes the window to lower the need for heating and cooling, one that assumes that the office is in use during the daytime, one based on user presence and one limiting the perpendicular component of the incident solar irradiation to avoid glare and too strong daylight. The control mechanisms were compared using computer simulations. A simplified approach based on the balance temperature concept was used instead of performing complete building simulations. The results show that an occupancy-based control system is clearly beneficial and also that the best way to combine the panes in the switchable window differs depending on the balance temperature of the building and on the climate. It is also shown that it can be beneficial to have different window combinations for different orientations.     

Properties of p-type amorphous silicon carbide window layers prepared using boron trifluoride

One set (A) of undoped and three sets (B, C and D) of doped hydrogenated amorphous silicon carbide samples have been made in the framework of a research plan for obtaining high quality p-type window layers by radiofrequency glow discharge of silane-based gas mixtures. The samples of sets A and B were made using different RF-power-density to mass-flow ratios for various methane percentages in the gas mixture. The best carbon incorporation in the amorphous silicon lattice was obtained at the highest RF-power density. The properties of sets C and D, prepared using different RF-power densities and silane and methane propertions have been analysed as functions of the concentration of borom trifluoride with respect to silane. In both cases, the optical gap E_G, after a slight initial decrease, remains at a value of approximately 2.1 eV without quenching in the dopiong ranges covered. The best conductivity obtained is 2 × 10⁻⁷ (μ cm)⁻¹. IR spectra allow to associate these features with the structural quality of the films.     

Oxygen modified diamond-like carbon as window layer for amorphous silicon solar cells

In the present study, the effect of in situ layer-by-layer oxygen plasma treatment (OPT) on optical, nano-mechanical and electrical properties of layer-by-layer diamond-like carbon (DLC) thin films was explored. In situ layer-by-layer OPT on layer-by-layer DLC films led to drastic variation of optical band gap from 1.25 eV to 2.6 eV and hardness from 16.1 GPa to 25.3 GPa. Wide band gap and the band gap feasibility over wide range may lead to its realization as p-type window layer in p–i–n solar cells and variable band gap layers in tandem solar cells. Simulations of a-Si:H based p–i–n solar cells was also carried out by considering OPT–DLC films as p-type window layers that yielded maximum efficiency of 8.9%. In addition, due to high hardness and other excellent nano-mechanical properties, these OPT–DLC films can be treated as hard, protective and encapsulate layers on solar cells particularly in n–i–p configuration. It is important to mention that OPT–DLC film as p-layer can minimize the use of additional hard, protective and encapsulate layer.     

Organic esters of phosphoric acid as electrolytes for a protonic photoelectrochromic window

The paper deals with phosphoric acid organic esters such as commercially available diphenylphosphate and custom made cyclic phosphoric ester of oligo(propylene oxide). The N,N-dimethylformamide and propylene carbonate solutions of these compounds were tested for potential application as electrolytes in a protonic electrochromic cell with tungsten trioxide as an active compound. As a reference, a solution of phosphoric acid of identical concentration was used. Cyclic chronovoltamperometry studies were used to test both the stability window of the electrolytes on a platinum electrode and the stability of indium tin oxide and tungsten trioxide electrodes against the electrolyte solution. The proton intercalation process was also studied. The experiments were performed both for dry solutions (vacuum drying of compounds) and for ones, which were on purpose contaminated with water. Additionally, the dc conductivity of the studied systems was measured for the whole possible operational temperature range. Generally, it was observed that the ester solutions give a better photochromic response of the WO₃ electrode but are more aggressive to its surface. This observation is valid especially for the water-contaminated systems.     

Effects of window size and thermal mass on building comfort using an intelligent ventilation controller

A prototype microcomputer-controlled thermostat was developed that can manage airflow according to cooling the needs in a building and the resources in the environment. This intelligent control system measures both indoor and outdoor temperature and uses decision rules to control a whole-house fan, in addition to the furnace and air conditioner. No such residential thermostat is currently commercially available. This paper presents the controller strategy that optimizes cooling with outdoor air. This paper also quantifies the effects of modifying the amount of thermal mass and the window area on indoor comfort when using this controller. These test confirm that smaller windows and more mass performed better than larger windows and less mass, and that higher volumes of controlled ventilation outperformed fixed ventilation rates.     

Multi-objective optimisation of horizontal axis wind turbine structure and energy production using aerofoil and blade properties as design variables

The design of wind turbine blades is a true multi-objective engineering task. The aerodynamic effectiveness of the turbine needs to be balanced with the system loads introduced by the rotor. Moreover the problem is not dependent on a single geometric property, but besides other parameters on a combination of aerofoil family and various blade functions. The aim of this paper is therefore to present a tool which can help designers to get a deeper insight into the complexity of the design space and to find a blade design which is likely to have a low cost of energy. For the research we use a Computational Blade Optimisation and Load Deflation Tool (CoBOLDT) to investigate the three extreme point designs obtained from a multi-objective optimisation of turbine thrust, annual energy production as well as mass for a horizontal axis wind turbine blade. The optimisation algorithm utilised is based on Multi-Objective Tabu Search which constitutes the core of CoBOLDT. The methodology is capable to parametrise the spanning aerofoils with two-dimensional Free Form Deformation and blade functions with two tangentially connected cubic splines. After geometry generation we use a panel code to create aerofoil polars and a stationary Blade Element Momentum code to evaluate turbine performance. Finally, the obtained loads are fed into a structural layout module to estimate the mass and stiffness of the current blade by means of a fully stressed design. For the presented test case we chose post optimisation analysis with parallel coordinates to reveal geometrical features of the extreme point designs and to select a compromise design from the Pareto set. The research revealed that a blade with a feasible laminate layout can be obtained, that can increase the energy capture and lower steady state systems loads. The reduced aerofoil camber and an increased L/D-ratio could be identified as the main drivers. This statement could not be made with other tools of the research community before.     

A new modeling procedure for circuit design and performance prediction of evaporator coils using CO2 as refrigerant

The replacement of environmentally damaging synthetic refrigerants due to their ODP or GWI potential by natural refrigerants such as CO₂ is now up in the research agenda. Moreover, current energy supply concerns make of efficiency another first priority issue to dictate new stringent design criteria for industrial and commercial equipment. Heat exchangers are the most important components in refrigeration systems where they are used as evaporators or condensers and their design and operation have a considerable impact on overall system performance. Hence, it is important to better understand their thermal and hydrodynamic behaviour in order to improve their design and operation. Numerical simulation represents a very efficient tool for achieving this objective. In this paper, a new modeling approach, accounting for the heat transfer the hydrodynamics of the problem and intended to predict the dynamic behaviour of a refrigeration coil under dry conditions is proposed. A related FORTRAN program was developed, allowing the study of a large range of complex refrigerant circuit configurations. The equations describing these aspects are strongly coupled, and their decoupling is reached by using an original method of resolution. Circuits may have several inlets, outlets, bifurcations and feed one or several other tubes inlets. The coil was subdivided into several elementary control volumes and its analysis provided detailed information in X, Y and Z directions. Validation was performed with data from a CO₂ secondary refrigeration loop test bench built in CanmetENERGY Laboratories. These data were predicted satisfactorily over the operating range corresponding to refrigeration applications. Exemplary simulations were then performed on an evaporator typically employed in supermarkets, showing the effect of circuiting on operation and performance. Even though circuiting is common practice in refrigeration this simulation shows that care must be exercised in making the selection. A two-circuit configuration was chosen for analysis in this investigation. In terms of capacity and heat transfer, it was shown that the two circuits were well balanced in terms of pressure drop and heat transfer capacity. Low CO₂ pressure drop resulted in reduced temperature glide as compared to a single circuit.     

Thermal and Stress Analysis of Glazing in Fires and Glass Fracture Modeling with a Probabilistic Approach

The aim of the study is to predict the thermal and stress behavior of a framed glass subjected to typical fire conditions, and the initial glass fracture time and locations using a probabilistic approach as an alternative to Pagni's deterministic criterion. Thermal stresses in glass have been little researched. The probabilistic approach has the advantage of taking into account some uncertainties such as the edge conditions. The model employed is based on stress and conduction heat transfer models, a spectral discrete ordinates radiation model, and a failure probability model. Some results of its verification and applications are reported here.     

Microcrystalline silicon solar cell using p-a-Si:H window layer deposited by photo-CVD method

A p-a-Si:H layer, deposited by a photo-assisted chemical vapor deposition (photo-CVD) method, was adopted as the window layer of a hydrogenated microcrystalline silicon (μc-Si:H) solar cell instead of the conventional p-μc-Si:H layer. We verified the usefulness of p-a-Si:H for the p-layer of the μc-Si:H solar cell by applying it to SnO₂-coated glass substrate. It was found that the quantum efficiency (QE) characteristics and solar cell performance strongly depend on the p-a-Si:H layer thicknesses. We applied boron-doped nanocrystalline silion (nc-Si:H) p/i buffer layers to μc-Si:H solar cells and investigated the correlation of the p/i buffer layer B₂H₆ flow rate and solar cell performance. When the B₂H₆ flow rate was 0.2 sccm, there was a little improvement in fill factor (FF), but the other parameters became poor as the B₂H₆ flow rate increased. This is because the conductivity of the buffer layer decreases as the B₂H₆ flow rate increases above appropriate values. A μc-Si:H single-junction solar cell with ZnO/Ag back reflector with an efficiency of 7.76% has been prepared.     

A study on the design and analysis of a heat pump heating system using wastewater as a heat source

In this study, the compression heat pump system using wastewater, as a heat source, from hotel with sauna was designed and analyzed. This study was performed to investigate the feasibility of the wastewater use for heat pump as a heat source and to obtain engineering data for system design. This heat pump system uses off-peak electricity that is a cheap energy compared to fossil fuel in Korea. For this, the charging process of heat into the hot water storage tank is achieved only at night time (22:00–08:00). TRNSYS was used for the system simulation with some new components like the heat pump, which we create ourselves.As a result, it was forecasted that the yearly mean COP of heat pump is about 4.8 and heat pump can supply 100% of hot water load except weekend of winter season. The important thing that should be considered for the system design is to decrease the temperature difference between condenser and evaporator working fluids during the heat charging process by the heat pump. This heat pump system using wastewater from sauna, public bath, building, etc. can therefore be effectively applied not only for water heating but also space heating and cooling in regions like as Korea.     

CdTe solar cell degradation studies with the use of CdS as the window material

We present in this work the degradation effects with time in thin film CdTe/CdS solar cells, where the CdS and CdTe layers are deposited by chemical bath deposition (CBD) and close space vapor transport (CSVT), respectively. The CdS thin films were grown from different baths by varying the S/Cd ratio. The variation of the S/Cd ratio allowed us to control the morphology and the density of defects, thus giving rise to better quality CBD CdS films. Depending on the S/Cd ratio an improvement of the morphology and capacitance signal was observed, these factors have also an influence on the open-circuit voltage, short-circuit current density, fill factor and conversion efficiency of the solar cell. The variation with time of these parameters in our devices was tracked during a period of 3 years measured directly on the exposed back contact regions (CdTe/Cu/Au). A discussion on the deterioration of the photovoltaic (PV) performance of the solar cells is presented in correlation with the local environmental conditions. This particular environment has contamination, and represents another type of stress for standard PV operations. These conditions reduce the mean life time of solar cells beyond short periods; this can be of interest for PV community.     

Trends in design of distributed energy systems using hydrogen as energy vector: A systematic literature review

Currently, a significant transformation for energy systems has emerged as a result of the trend to develop an energy framework without fossil fuel reliance, the concerns about climate change and air quality, and the need to provide electricity to around of 17% of world population who lacks the service. Accordingly, the deployment of power plants located close to end-users and including multiple energy sources and carriers, along with the growing share of renewable energies, have suggested changes in the energy sector. Despite their potential capabilities, the design of distributed energy systems (DES) is a complex problem due to the simultaneous goals and constraints that need to be considered, as well as to the high context dependence of this kind of projects. For these reasons, in this work a systematic literature review of DES including hydrogen as energy vector, was made analyzing 106 research papers published between the years 2000–2018, and extracted from Scopus^® and Web of Science databases. The aim was to identify how hydrogen is employed (technologies, uses) and the criteria that are evaluated (economic, technical, social and environmental) when these systems are designed, planned and/or operated. The results constitute a baseline information covering the type of technologies, equipment sizes and hydrogen applications, that could be valuable for the preliminary stages of research or project planning of DES involving hydrogen. Furthermore, other factors have also been identified, such as the focus on techno-economic issues, and the lack of considering socio/political aspects and the uncertainty about input data like weather conditions, energy prices and demands. Additionally, a more integrated approach is needed including all the hydrogen supply chain stages and project stakeholders, to tackle issues like safety of the energy systems that could produce consumer rejections.     

Finned-tube condenser design optimization using thermoeconomic isolation

Using a detailed system model as a comparison, this study shows that isolating the condenser component and optimizing it independently by minimizing the entropy generation in the condenser component alone, also known as thermoeconomic isolation, can be a practical way to design the condenser for optimum air-conditioning system efficiency. This study is accomplished by comparing the optimum design determined by maximizing the entire system’s COP, an undisputed method, with the optimum design determined by minimizing the entropy generation in the isolated condenser component, with consistent constraints used for the two methods. The choice of component junction constraints used in the isolated model is critical and discussed in detail.The resulting optimum designs from the isolated model produced a COP within 0.6%–1.7% of the designs found by optimizing the COP using an entire system model. Additionally, a 65% reduction in computation time was achieved.     

The traditional Yemeni window and natural lighting

The traditional Yemeni window is considered to be one of the most important elements that characterize the yemeni architecture. The beauty of the traditional Yemeni window comes from its four main components which combined the functions of view, lighting, ventilation, protection, and privacy. These functions can be controlled by the occupants according to their social and environmental needs. The four main components are the lower part (Taqah), the fanlight (Qamariyah), the wooden external overhang (Konnah), and the small vent (Shaquos). Since fanlights provide natural lighting during day-time, the area of the lower part can be reduced and its exterior shutters can be closed without the need for artificial lighting. The internal natural lighting that is provided by the upper and lower parts of the window was investigated to see its quality. In this investigation, there were two main goals. The first is the contribution and quality of the internal light provided by the Qamariyah when shutters are closed. The second is the effect of the internal simple white cloth curtains, in the lower part, in the internal light quality. Visual measurements were taken in a typical room of a traditional house of the Old City of Sana'a, Yemen. From the findings, it was found that the fanlights (Qamariyat) provide low and soft homogeneous internal lighting which was as low as 22 lux average. However, the occupants have the ability to increase level of lighting to as high as 600 or 700 lux. This can be done simply by deciding which shutter to open and how many of them to be opened. In this paper, the methodology and findings will be presented and discussed.     

Preparation and properties of CdS thin films prepared on cold substrate as a window layer for solar cells

CdS films, usually, prepared on hot substrate at temperature range from 180 to 220°C. The electrical properties of the films are dependent on many parameters such as film thickness, deposition rate, film structure and substrate temperature. To control all these parameters to get film resistivity suitable for manufacturing solar cells, it needs a lot of precautions. CdS prepared on cold substrate could be the solution for this problem. Evaporation of CdS film at constant evaporation rate, then annealed in open air up to 600°C according to the film thickness. The resultant film have been studied. The properties of the films were comparable to the films prepared by the other methods with less control complexity.