Active shading systems in buildings have emerged as a high performing shading solution that selectively and optimally controls daylight and heat gains. Active shading systems are increasingly used in ...buildings, due to their ability to mainly improve the building environment, reduce energy consumption and in some cases generate energy. They may be categorized into three classes: smart glazing, kinetic shading and integrated renewable energy shading. This paper reviews the current status of the different types in terms of design principle and working mechanism of the systems, performance, control strategies and building applications. Challenges, limitations and future opportunities of the systems are then discussed. The review highlights that despite its high initial cost, the electrochromic (EC) glazing is the most applied smart glazing due to the extensive use of glass in buildings under all climatic conditions. In terms of external shadings, the rotating shading type is the predominantly used one in buildings due to its low initial cost. Algae façades and folding shading systems are still emerging types, with high initial and maintenance costs and requiring specialist installers. The algae façade systems and PV integrated shading systems are a promising solution due to their dual benefits of providing shading and generating electricity. Active shading systems were found to save 12 to 50% of the building cooling electricity consumption.
In recent years solar energy has received worldwide attention in the field of renewable energy systems. Among the various research thrusts in solar PV, the most proverbial area is extracting maximum ...power from solar PV system. Application dof Maximum Power Point Tracking (MPPT) for extracting maximum power is very much appreciated and holds the key in developing efficient solar PV system. In this paper, a state of the art review on various maximum power point techniques for solar PV systems covering timeworn conventional methods and latest soft computing algorithms is presented. To date critical analysis on each of the method in terms of (1) tracking speed, (2) algorithm complexity, (3) Dynamic tracking under partial shading and (4) hardware implementation is not been carried out. In this regard the authors have attempted to compile a comprehensive review on various solar PV MPPT techniques based on the above criteria. Further, it is envisaged that the information presented in this review paper will be a valuable gathering of information for practicing engineers as well as for new researchers.
•Proposes a permanent structuring technique to configure modules in a PV array.•TCT connected PV array is physically structured based on Odd-Even technique.•The proposed technique is simple in ...implementation and cost-effective.
This paper proposes an improved permanent structuring technique to configure the panels in photo voltaic (PV) array so that optimum power output can be achieved under partial shading conditions. The proposed technique enables the structure to redistribute shading effect on complete PV array by using panel physical positions alternatively. The PV modules are connected in TCT configuration and this TCT configured array is structured based on ODD-EVEN pattern. The ODD-EVEN structures of panels don’t change electrical connections of TCT connected PV array. The rendition of proposed structure of PV array is investigated under various shading conditions. The proposed technique has resulted in an appreciably improved power generation of PV array at output terminals. The technique mitigates occurrence of multiple local maxima and thus avoids the necessity of complex maximum power point tracking algorithm. The simple and cost-effective PV array structure is the additional merit associated with this configuration.
Commercial buildings consume around 20% of the total energy utilized in the U.S. The use of shading devices in buildings has the potential to reduce building energy consumption while also providing a ...more desirable indoor environment for building occupants. Similarly, lighting device controls help reduce lighting energy consumption as well as internal loads. However, there is lack of full-scale experimental testing of integrated dynamic shading and lighting controls. This study presents full-scale experimental testing data to quantify these energy and daylighting impacts. Testing was performed utilizing two different control strategies, in three different orientations under three different types of sky conditions. The shading device was also used in conjunction with two different types of glazing. An average of 25.4% cooling energy savings and 48.5% lighting energy savings was achieved. Visual discomfort evaluated using Simplified Daylight Glare Probability was prevented more than 85% of time during occupied hours. Improvement in daylight levels evaluated using Useful Daylight Illuminance was also achieved. Finally, analysis of the relationship between the illuminance level measured at the work plane and a ceiling illuminance sensor is performed to translate the real-world applicability of shading device controls.
•Full-scale testing conducted of dynamic venetian blinds and lighting control.•2 control strategies tested in three orientations, including east, south and west.•49% lighting and 25% HVAC energy savings is achieved compared to the baseline.•Acceptable levels of glare are achieved 85% of the time.•Recommendation for shading control using different sensor position.
Most high-rise office buildings in the tropics, particularly in Malaysia and Singapore, exceed the required level of the energy efficiency index. The implementation of conventional shading systems in ...the tropics has been proven to have limitations in terms of controlling the quantity and quality of received solar light throughout the year, especially at different solar angles with varying sky conditions. Therefore, the main objective of this work is to investigate the challenges and future trends of solar shading systems by examining their mechanisms, functions and materials for application in tropical regions. This study used evidence review to evaluate various types and models of shading systems based on a systematic method to identify patterns and trends through classification and comparison. Three main categories of shading systems were identified based on the energy involvement and the design approach: (i) passive systems with zero energy use, (ii) active systems that use mechanical devices and (iii) hybrid systems integrated with a biomimetic approach. Specific conclusions were drawn to emphasise the efficiency of developed shading systems in the tropics.
Passive design strategies are the most feasible and economic ways of energy and thermal management in buildings, if appropriately incorporated at the conceptual design stage. Though many works have ...been reported on the application of external shading options, a shading strategy that incorporates the features of both external shading devices and self-shading envelope, is yet to be explored. The present study was focused on the energy saving potential and economics of incorporating external shading devices with self-shading envelope for a multi-story hotel building in hot-humid climate of Saudi Arabia. The modeling and the energy simulations were performed by DesignBuilder (Version 4.5.0.148). According to the base-design geometry of the building, appropriate shading options were proposed for the north, south, north-east, north-west, south-east and south-west facades. External walls and roof were insulated with fiber glass and windows were double-glazed (DG), in compliance with the Saudi Building Code - 601. The shading strategy was chosen in such a way that it forms part of a self-shading envelope while improving energy performance and contributing additional space at very affordable cost. The results show that the proposed shading could save the annual energy consumption of the building by 20.5% compared to the base case. The payback period for the additional investment required for incorporating the passive shading strategy is estimated to be 2 years. Study of another option by improving the baseline insulation and glazing (with polyurethane in walls and roof and triple low-e glazed shows, without shading) shows that it saves only 5% of annual energy consumption, and the payback period is unacceptably long (84 years).
•Effect of shading strategy on energy performance of multi-story hotel building.•The shading strategy combines shading devices and self-shading envelope.•The proposed shading configuration could save 20.5% of annual energy consumption.•The additional cost for the shading can be recovered in 2 years.
•The current body of knowledge on photovoltaic integrated shading devices (PVSDs) is systematically summarized.•24 types of theoretically available PVSD are identified and illustrated.•The basic ...information of 21 architectural cases with the application of PVSD is tabulated.•Two current obstacles to the PVSD development are identified and analyzed.•The focuses of current studies on PVSD have been on the technical approach, office building, and equator-facing orientation.
Building-integrated photovoltaics (BIPVs) have come to be regarded as a promising technology that reduces the life-cycle costs of building construction and generates energy simultaneously. In this regard, photovoltaic integrated shading devices (PVSDs) constitute an important part of BIPVs and play a role in generating power by transforming the unwanted radiation and in reducing cooling energy consumption. Despite the expansion of the literature in recent years (2016–2017), a comprehensive review exploring the studies on PVSD is still lacking. To fill this research gap, a systematic review of the literature on PVSD was conducted. The current body of knowledge on PVSD is summarized, including aspects such as PVSD types, PV material, orientations, tilt angles, and research approaches. Several noteworthy conclusions are drawn based on the quantitative analysis of 43 journal papers on PVSD. The majority of the studies are South Korea-based (35.9%), followed by China, Greece, and Switzerland. In addition, the focus of the literature has been on the technical approach (76.5%), office building (73.3%), and equator-facing orientation (57.1%). Only 15 types of PVSD have hitherto been studied, with the emphasis on two types: the inclined single panel and horizontal louvres between double layers. Moreover, 21 architectural cases of PVSD in practice are presented and two obstacles to PVSD development are discussed. Suggestions for future study are made, including intensifying the focus on PVSD in countries with the significant solar source, such as Singapore and Australia; diversifying the exploration of multiple PVSD types (instead of only two types); and emphasizing multi-objective optimization studies on PVSD. The review can serve as a quick reference for future research and may find utility in providing an overview of PVSD to both industry practitioners and academicians.
•Effect of external venetian blind on nearly zero-energy buildings was studied.•Energy performance of external shading in different climate regions was quantified.•Multiple optimization design of ...shading arrangement parameters was discussed.•A new index was proposed for evaluating the energy efficiency of external shading.
The development and promotion of nearly zero-energy buildings (NZEBs) is an inevitable trend of building energy conservation, and external venetian blind shading (EVBS) is one of the most effective technologies for NZEBs. Therefore, this study aims to analyze and optimize the energy-saving performance of EVBS for NZEBs in different climate regions of China. Based on EnergyPlus, the optimal shading arrangements of NZEBs are obtained by evaluating the shading performance of different shading slat angles, orientations, window-to-wall ratios (WWRs) and locations. The results show that the energy saving potential of EVBS for NZEBs is significant, especially in southwest of China. And the energy-saving trends of EVBS with different shading arrangements are similar regardless of the climates, and the maximum energy saving potential per unit window area of EVBS is obtained in slat angle of 0°, west orientation and low WWR. The total energy saving potential (P) gradually decreases first and then increases rapidly as the slat angle increases for all slat angle (0°~180°) shading conditions. And the multi-orientation shading effect is the sum of each single-orientation shading effect. In addition, the cooling efficiency index (CEI) is proposed to evaluate the importance of shading to reduce the cooling demand of buildings, and to guide the improvement of the self-performance of shading. This research will be helpful in guiding the application of EVBS for residential NZEBs in different climate regions of China.
Streaming rendering, e.g., rendering in the cloud and streaming via a mobile connection, suffers from increased latency and unreliable connections. High quality framerate upsampling can hide these ...issues, especially when capturing shading into an atlas and transmitting it alongside geometric information. The captured shading information must consider triangle footprints and temporal stability to ensure efficient video encoding. Previous approaches only consider either temporal stability or sample distributions, but none focuses on both. With SnakeBinning, we present an efficient triangle packing approach that adjusts sample distributions and caters for temporal coherence. Using a multi‐dimensional binning approach, we enforce tight packing among triangles while creating optimal sample distributions. Our binning is built on top of hardware supported real‐time rendering where bins are mapped to individual pixels in a virtual framebuffer. Fragment shader interlock and atomic operations enforce global ordering of triangles within each bin, and thus temporal coherence according to the primitive order is achieved. Resampling the bin distribution guarantees high occupancy among all bins and a dense atlas packing. Shading samples are directly captured into the atlas using a rasterization pass, adjusting samples for perspective effects and creating a tight packing. Comparison to previous atlas packing approaches shows that our approach is faster than previous work and achieves the best sample distributions while maintaining temporal coherence. In this way, SnakeBinning achieves the highest rendering quality under equal atlas memory requirements. At the same time, its temporal coherence ensures that we require equal or less bandwidth than previous state‐of‐the‐art. As SnakeBinning outperforms previous approach in all relevant aspects, it is the preferred choice for texture‐based streaming rendering.
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