scholarly journals EVALUASI KINERJA SELUBUNG BANGUNAN GEDUNG AGAPE UNIVERSITAS KRISTEN DUTA WACANA YOGYAKARTA

2021 ◽  
Vol 8 (2) ◽  
pp. 86
Author(s):  
Christian Nindyaputra Octarino ◽  
Henry Feriadi
Keyword(s):  
Energy Conservation ◽  
High Performance ◽  
Negative Impact ◽  
High Energy ◽  
Building Envelope ◽  
National Standards ◽  
Conservation Strategies ◽  
Air Conditioning System ◽  
Thermal Transfer ◽  
Building Designs

Di tengah fenomena perubahan iklim dan pemanasan global, arsitektur sudah semestinya turut berperan dalam menjaga lingkungan dengan menghadirkan desain-desain bangunan yang memiliki performa tinggi, yang dapat memberikan kenyamanan optimal bagi penghuninya tanpa mengorbankan kualitas lingkungan di sekitarnya. Karakter iklim Indonesia yang merupakan iklim tropis menyebabkan tingginya temperatur lingkungan, sehingga berpotensi menimbulkan ketidaknyamanan bagi penghuni bangunan. Upaya dalam meningkatkan kenyamanan tentu akan membutuhkan konsumsi energi yang tinggi, sehingga perlu dipikirkan strategi konservasi energi agar bangunan tidak berdampak negatif terhadap lingkungan. Sebagai bagian dari kompleks Universitas Kristen Duta Wacana Yogyakarta, Gedung Agape adalah gedung dengan fungsi perkantoran yang menggunakan sistem pendingin udara. Setelah digunakan selama 12 tahun, Gedung ini memiliki evaluasi kenyamanan termal yang cukup baik oleh para penghuninya. Namun demikian, diyakini Gedung Agape masih memiliki potensi penghematan energi yang cukup besar melalui kinerja selubung bangunannya. Studi ini bertujuan untuk mengevaluasi bagaimana kinerja selubung bangunan Gedung Agape UKDW dalam fungsinya mereduksi panas dari lingkungan serta menentukan strategi apa saja yang dapat diterapkan untuk menekan nilai Overall Thermal Transfer Value (OTTV) dalam upaya mendukung konservasi energi pada bangunan. Standar Nasional Indonesia tentang konservasi energi Gedung menetapkan nilai OTTV maksimal sebesar 35 W/m2. Berdasarkan hasil perhitungan dengan worksheet, didapatkan nilai OTTV Gedung Agape sebesar 49,06 35 W/m2, cukup jauh dari standar SNI. Beberapa strategi untuk menekan nilai OTTV dicoba disimulasikan melalui modifikasi material bukaan dan penyesuaian window to wall ratio, sehingga pada akhirnya dapat mencapai 34,86 W/m2.EVALUATION OF BUILDING ENVELOPE PERFORMANCE ON AGAPE BUILDING UNIVERSITAS KRISTEN DUTA WACANA YOGYAKARTA In response to the worldwide issue about climate change and global warming, architecture should play a role to protecting the environment by presenting high performance building designs. This kind of building can provide optimal comfort for its occupants without sacrificing the quality of the surrounding environment. The character of Indonesia's tropical climate, causes high environmental temperatures, thus potentially causing discomfort for building occupants. The effort to increase comfort will certainly require high energy consumption, so it is necessary to consider about energy conservation strategies to minimize negative impact on the environment. As a part of Universitas Kristen Duta Wacana area, Agape is an office building that uses air conditioning system. After being used for 12 years, this building has a satisfactory evaluation about the thermal comfort from the occupants. However, it is believed that the building still has considerable potential of energy saving through the performance of the building envelope. This study aims to evaluate performance of Agape Building’s envelope in term of heat transfer reduction and determine strategies that can be applied to reduce the Overall Thermal Transfer Value (OTTV) value to support energy conservation. Indonesian National Standards (SNI) about building’s energy conservation determine a maximum OTTV value of 35 W/m2. Based on calculation, the OTTV value of Agape Building was obtained 49,06 W/m2, has not been able to reach the SNI standard. Several strategies to reduce the OTTV value have been simulated by modifying the opening material and adjusting the window to wall ratio, so that in the end the OTTV value could meet the standards, 34,86 W/m2.

Impact of roof shading on building energy performance in warm & humid climatic places of India

2020 ◽  
pp. 50-64
Author(s):  
Kuladeep Kumar Sadevi ◽  
Avlokita Agrawal
Keyword(s):  
Energy Consumption ◽  
Energy Conservation ◽  
Energy Performance ◽  
General Assumption ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Passive Cooling ◽  
Base Case ◽  
U Value ◽  
The Impact

With the rise in awareness of energy efficient buildings and adoption of mandatory energy conservation codes across the globe, significant change is being observed in the way the buildings are designed. With the launch of Energy Conservation Building Code (ECBC) in India, climate responsive designs and passive cooling techniques are being explored increasingly in building designs. Of all the building envelope components, roof surface has been identified as the most significant with respect to the heat gain due to the incident solar radiation on buildings, especially in tropical climatic conditions. Since ECBC specifies stringent U-Values for roof assembly, use of insulating materials is becoming popular. Along with insulation, the shading of the roof is also observed to be an important strategy for improving thermal performance of the building, especially in Warm and humid climatic conditions. This study intends to assess the impact of roof shading on building’s energy performance in comparison to that of exposed roof with insulation. A typical office building with specific geometry and schedules has been identified as base case model for this study. This building is simulated using energy modelling software ‘Design Builder’ with base case parameters as prescribed in ECBC. Further, the same building has been simulated parametrically adjusting the amount of roof insulation and roof shading simultaneously. The overall energy consumption and the envelope performance of the top floor are extracted for analysis. The results indicate that the roof shading is an effective passive cooling strategy for both naturally ventilated and air conditioned buildings in Warm and humid climates of India. It is also observed that a fully shaded roof outperforms the insulated roof as per ECBC prescription. Provision of shading over roof reduces the annual energy consumption of building in case of both insulated and uninsulated roofs. However, the impact is higher for uninsulated roofs (U-Value of 3.933 W/m2K), being 4.18% as compared to 0.59% for insulated roofs (U-Value of 0.33 W/m2K).While the general assumption is that roof insulation helps in reducing the energy consumption in tropical buildings, it is observed to be the other way when insulation is provided with roof shading. It is due to restricted heat loss during night.

Efficient Co-Harvesting of Solar Energy and Low-Grade Heat by Molecular Photoswitches for High Energy Density, Long-Term Stable Solar Thermal Battery

2019 ◽  
Author(s):  
Zhao-Yang Zhang ◽  
Tao LI
Keyword(s):  
Energy Density ◽  
Solar Energy ◽  
High Performance ◽  
High Energy ◽  
Solar Thermal ◽  
High Energy Density ◽  
Low Grade ◽  
Thermal Battery ◽  
Low Grade Heat

Solar energy and ambient heat are two inexhaustible energy sources for addressing the global challenge of energy and sustainability. Solar thermal battery based on molecular switches that can store solar energy and release it as heat has recently attracted great interest, but its development is severely limited by both low energy density and short storage stability. On the other hand, the efficient recovery and upgrading of low-grade heat, especially that of the ambient heat, has been a great challenge. Here we report that solar energy and ambient heat can be simultaneously harvested and stored, which is enabled by room-temperature photochemical crystal-to-liquid transitions of small-molecule photoswitches. The two forms of energy are released together to produce high-temperature heat during the reverse photochemical phase change. This strategy, combined with molecular design, provides high energy density of 320-370 J/g and long-term storage stability (half-life of about 3 months). On this basis, we fabricate high-performance, flexible film devices of solar thermal battery, which can be readily recharged at room temperature with good cycling ability, show fast rate of heat release, and produce high-temperature heat that is >20<sup> o</sup>C higher than the ambient temperature. Our work opens up a new avenue to harvest ambient heat, and demonstrate a feasible strategy to develop high-performance solar thermal battery.

Efficient Co-Harvesting of Solar Energy and Low-Grade Heat by Molecular Photoswitches for High Energy Density, Long-Term Stable Solar Thermal Battery

2019 ◽  
Author(s):  
Zhao-Yang Zhang ◽  
Tao LI
Keyword(s):  
Energy Density ◽  
Solar Energy ◽  
High Performance ◽  
High Energy ◽  
Solar Thermal ◽  
High Energy Density ◽  
Low Grade ◽  
Thermal Battery ◽  
Low Grade Heat

Solar energy and ambient heat are two inexhaustible energy sources for addressing the global challenge of energy and sustainability. Solar thermal battery based on molecular switches that can store solar energy and release it as heat has recently attracted great interest, but its development is severely limited by both low energy density and short storage stability. On the other hand, the efficient recovery and upgrading of low-grade heat, especially that of the ambient heat, has been a great challenge. Here we report that solar energy and ambient heat can be simultaneously harvested and stored, which is enabled by room-temperature photochemical crystal-to-liquid transitions of small-molecule photoswitches. The two forms of energy are released together to produce high-temperature heat during the reverse photochemical phase change. This strategy, combined with molecular design, provides high energy density of 320-370 J/g and long-term storage stability (half-life of about 3 months). On this basis, we fabricate high-performance, flexible film devices of solar thermal battery, which can be readily recharged at room temperature with good cycling ability, show fast rate of heat release, and produce high-temperature heat that is >20<sup> o</sup>C higher than the ambient temperature. Our work opens up a new avenue to harvest ambient heat, and demonstrate a feasible strategy to develop high-performance solar thermal battery.

scholarly journals Intelligent control for energy conservation of air conditioning system in manufacturing systems

2021 ◽  
Vol 7 ◽  
pp. 2125-2137
Author(s):  
Kung-Jeng Wang ◽  
Teshome Bekele Dagne ◽  
Chiuhsiang Joe Lin ◽  
Bereket Haile Woldegiorgis ◽  
Hong-Phuc Nguyen
Keyword(s):  
Energy Conservation ◽  
Intelligent Control ◽  
Air Conditioning ◽  
Manufacturing Systems ◽  
Air Conditioning System

scholarly journals Defect-induced B4C electrodes for high energy density supercapacitor devices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Özge Balcı ◽  
Merve Buldu ◽  
Ameen Uddin Ammar ◽  
Kamil Kiraz ◽  
Mehmet Somer ◽  
...  
Keyword(s):  
Active Carbon ◽  
High Performance ◽  
Carbon Sources ◽  
High Energy ◽  
High Energy Density ◽  
Synthesis Conditions ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
G Ratio ◽  
Energy And Power Density

AbstractBoron carbide powders were synthesized by mechanically activated annealing process using anhydrous boron oxide (B2O3) and varying carbon (C) sources such as graphite and activated carbon: The precursors were mechanically activated for different times in a high energy ball mill and reacted in an induction furnace. According to the Raman analyses of the carbon sources, the I(D)/I(G) ratio increased from ~ 0.25 to ~ 0.99, as the carbon material changed from graphite to active carbon, indicating the highly defected and disordered structure of active carbon. Complementary advanced EPR analysis of defect centers in B4C revealed that the intrinsic defects play a major role in the electrochemical performance of the supercapacitor device once they have an electrode component made of bare B4C. Depending on the starting material and synthesis conditions the conductivity, energy, and power density, as well as capacity, can be controlled hence high-performance supercapacitor devices can be produced.

scholarly journals Recent Advances in the Synthesis of Polymer-Grafted Low-K and High-K Nanoparticles for Dielectric and Electronic Applications

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2942
Author(s):  
Bhausaheb V. Tawade ◽  
Ikeoluwa E. Apata ◽  
Nihar Pradhan ◽  
Alamgir Karim ◽  
Dharmaraj Raghavan
Keyword(s):  
Energy Density ◽  
Polymer Nanocomposites ◽  
High Performance ◽  
Breakdown Strength ◽  
Polymer Nanocomposite ◽  
High Energy ◽  
Polymer Chains ◽  
High Energy Density ◽  
Grafted Nanoparticles ◽  
Grafting From

The synthesis of polymer-grafted nanoparticles (PGNPs) or hairy nanoparticles (HNPs) by tethering of polymer chains to the surface of nanoparticles is an important technique to obtain nanostructured hybrid materials that have been widely used in the formulation of advanced polymer nanocomposites. Ceramic-based polymer nanocomposites integrate key attributes of polymer and ceramic nanomaterial to improve the dielectric properties such as breakdown strength, energy density and dielectric loss. This review describes the ”grafting from” and ”grafting to” approaches commonly adopted to graft polymer chains on NPs pertaining to nano-dielectrics. The article also covers various surface initiated controlled radical polymerization techniques, along with templated approaches for grafting of polymer chains onto SiO2, TiO2, BaTiO3, and Al2O3 nanomaterials. As a look towards applications, an outlook on high-performance polymer nanocomposite capacitors for the design of high energy density pulsed power thin-film capacitors is also presented.

Sulfur vacancies in Co9S8-x/N-doped graphene enhancing electrochemical kinetics to high-performance lithium sulfur batteries

2021 ◽  
Author(s):  
Haojie Li ◽  
Yihua Song ◽  
Kai Xi ◽  
Wei Wang ◽  
Sheng Liu ◽  
...  
Keyword(s):  
Cathode Materials ◽  
High Performance ◽  
Catalytic Conversion ◽  
High Energy ◽  
Electrochemical Kinetics ◽  
Lithium Sulfur Batteries ◽  
Doped Graphene ◽  
Sulfur Battery ◽  
Areal Capacity ◽  
Lithium Sulfur

A sufficient areal capacity is necessary for achieving high-energy lithium sulfur battery, which requires high enough sulfur loading in cathode materials. Therefore, kinetically fast catalytic conversion of polysulfide intermediates is...

scholarly journals Efficient Catalytic Conversion of Polysulfides by Biomimetic Design of “Branch-Leaf” Electrode for High-Energy Sodium–Sulfur Batteries

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Wenyan Du ◽  
Kangqi Shen ◽  
Yuruo Qi ◽  
Wei Gao ◽  
Mengli Tao ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Electrochemical Reaction ◽  
Molecular Layer ◽  
Specific Capacity ◽  
High Energy ◽  
Reduction Reaction ◽  
Biomimetic Design ◽  
Co Nanoparticles ◽  
Sodium Sulfur

AbstractRechargeable room temperature sodium–sulfur (RT Na–S) batteries are seriously limited by low sulfur utilization and sluggish electrochemical reaction activity of polysulfide intermediates. Herein, a 3D “branch-leaf” biomimetic design proposed for high performance Na–S batteries, where the leaves constructed from Co nanoparticles on carbon nanofibers (CNF) are fully to expose the active sites of Co. The CNF network acts as conductive “branches” to ensure adequate electron and electrolyte supply for the Co leaves. As an effective electrocatalytic battery system, the 3D “branch-leaf” conductive network with abundant active sites and voids can effectively trap polysulfides and provide plentiful electron/ions pathways for electrochemical reaction. DFT calculation reveals that the Co nanoparticles can induce the formation of a unique Co–S–Na molecular layer on the Co surface, which can enable a fast reduction reaction of the polysulfides. Therefore, the prepared “branch-leaf” CNF-L@Co/S electrode exhibits a high initial specific capacity of 1201 mAh g−1 at 0.1 C and superior rate performance.

A High-Performance Free-Standing Zn Anode for Flexible Zinc-Ion Batteries

Nanoscale ◽  
2021 ◽  
Author(s):  
Chenxi Gao ◽  
Jiawei Wang ◽  
Yuan Huang ◽  
Zixuan Li ◽  
Jiyan Zhang ◽  
...  
Keyword(s):  
Energy Density ◽  
High Performance ◽  
Low Cost ◽  
High Energy ◽  
Zinc Ion ◽  
High Energy Density ◽  
Free Standing ◽  
Energy Device ◽  
Zn Anode ◽  
Significant Attention

Zinc-ion batteries (ZIBs) have attracted significant attention owing to their high safety, high energy density, and low cost. ZIBs have been studied as a potential energy device for portable and...

scholarly journals Development and characterization of Nb3Sn/Al2O3 superconducting multilayers for particle accelerators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chris Sundahl ◽  
Junki Makita ◽  
Paul B. Welander ◽  
Yi-Feng Su ◽  
Fumitake Kametani ◽  
...  
Keyword(s):  
High Performance ◽  
High Energy ◽  
Particle Accelerators ◽  
Quality Factors ◽  
Critical Fields ◽  
Linear Accelerators ◽  
Cross Sectional ◽  
Low Field ◽  
Superconducting Radio Frequency

AbstractSuperconducting radio-frequency (SRF) resonator cavities provide extremely high quality factors > 1010 at 1–2 GHz and 2 K in large linear accelerators of high-energy particles. The maximum accelerating field of SRF cavities is limited by penetration of vortices into the superconductor. Present state-of-the-art Nb cavities can withstand up to 50 MV/m accelerating gradients and magnetic fields of 200–240 mT which destroy the low-dissipative Meissner state. Achieving higher accelerating gradients requires superconductors with higher thermodynamic critical fields, of which Nb3Sn has emerged as a leading material for the next generation accelerators. To overcome the problem of low vortex penetration field in Nb3Sn, it has been proposed to coat Nb cavities with thin film Nb3Sn multilayers with dielectric interlayers. Here, we report the growth and multi-technique characterization of stoichiometric Nb3Sn/Al2O3 multilayers with good superconducting and RF properties. We developed an adsorption-controlled growth process by co-sputtering Nb and Sn at high temperatures with a high overpressure of Sn. The cross-sectional scanning electron transmission microscope images show no interdiffusion between Al2O3 and Nb3Sn. Low-field RF measurements suggest that our multilayers have quality factor comparable with cavity-grade Nb at 4.2 K. These results provide a materials platform for the development and optimization of high-performance SIS multilayers which could overcome the intrinsic limits of the Nb cavity technology.

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