The influence of low-temperature surface induction on evacuation, pump-out hole sealing and thermal performance of composite edge-sealed vacuum insulated glazing

Hermeticity of vacuum edge-sealing materials are one of the paramount requirements, specifically, to the evolution of energy-efficient smart windows and solar thermal evacuated flat plate collectors. This study reports the design, construction and performance of high-vacuum glazing fabrication system and vacuum insulated glazing (VIG). Experimental and theoretical investigations for the development of vacuum edgeseal made of Sn-Pb-Zn-Sb-AlTiSiCu composite in the proportion ratio of 56:39:3:1:1 by % (CS-186) are presented. Experimental investigations of the seven constructed VIG samples, each of size 300mm·300mm·4 mm, showed that increasing the hot-plate surface temperatures improved the cavity vacuum pressure whilst expediting the pump-out hole sealing process but also increases temperature induced stresses. Successful pump-out hole sealing process of VIG attained at the hot-plate set point temperature of 50˚C and the approximate cavity pressure of 0.042 Pa was achieved. An experimentally and theoretically validated finite volume model (FVM) was utilised. The centre-of-pane and total thermal transmittance values are calculated to be 0.91 Wm-2K-1 and 1.05 Wm-2K-1, respectively for the VIG. FVM results predicted that by reducing the width of vacuum edge seal and emissivity of coatings the thermal performance of the VIG is improved

Design, fabrication and performance analysis of vacuum glazing units fabricated with low and high temperature hermetic glass edge sealing materials

Vacuum glazing is a vital development in the move to more energy efficient buildings. In vacuum glazing, an evacuated cavity supresses gaseous conduction and convection to provide high thermal resistance. A high vacuum pressure (less than 0.1 Pa) is required and must be maintained by a hermetic seal around the periphery, currently formed with either indium (i.e. low temperature sealing method) or solder glass (i.e. high temperature sealing method). This thesis reports the results of an experimental and theoretical investigation into the development of new low temperature (less than 200˚C) and novel high temperature (up to 450˚C) glass edge seals. A new low temperature composite edge seal was developed in which double and triple vacuum glazings each of dimensions 300x300mm were fabricated with measured vacuum pressures of 4.6x10-2Pa and 4.8x10-2Pa achieved respectively. A three dimensional finite element model of the fabricated design of composite edge sealed triple vacuum glazing was developed. [Continues.

Investigating the impact of cyber security risks and reliability scenarios under the influence of IoT on the Smart Grid environment

The modern infrastructure of the smart grid minimises the power losses and maintain the electric power flow closer to nominal values. It enables the bidirectional flow of energy between consumer end and generation end along with a communication flow. Due to increasing number of smart grid equipment, it is important to investigate security protection and appropriate recovery measures for the smart grid application. Cyber security measures are important to consider for improving the reliability and intelligence features of the smart grid. This paper investigated the security measurements and different standards to counter the future security threats to the smart grid power systems. False data injection and risk analysis is carried out along with an internet of thing (IoT) based security solution to increase the reliability of data flow and communication on the smart grid. The investigations are performed by creating a power system model on a MATALB/Simulink environment

Predicting the solar energy and space-heating energy performance for solid-wall detached house retrofitted with the composite edge-sealed triple vacuum glazing

© 2017 The Authors. Published by Elsevier Ltd. Triple-Vacuum-Glazing is regarded as evolutionary step in minimising the space-heating loss. This paper takes a comparative analysis approach to envisage space-heating supply required for achieving thermal-comfort temperatures and attainable solar energy gains to households with retrofit of composite edge-sealed triple-vacuum-glazing. Predictions of varying window-to-wall ratios on space-heating energy and solar energy gains for winter months are analysed. The notable winter and annual space-heating energy savings of 14.58% and 15.31%, respectively, were obtained with solid-wall detached-house retrofitted with triple-vacuum-glazed windows compared to single-glazed-windows. The heat-loss calculations show a prominent reduction from 12.92% to 2.69% when replacing single-glazed windows to triple-vacuum-glazed windows

Effect of Cavity Vacuum Pressure Diminution on Thermal Performance of Triple Vacuum Glazing

open access articleLong-term durability of the vacuum edge seal plays a significant part in retrofitting triple vacuum glazing (TVG) to existing buildings in achieving progress towards a zero-energy building (ZEB) target. Vacuum pressure decrement with respect to time between panes affects the thermal efficiency of TVG. This study reports a 3D finite element model, with validated mathematical methods and comparison, for the assessment of the influence of vacuum pressure diminution on the thermal transmittance (U value) of TVG. The centre-of-pane and total U values of TVG are calculated to be 0.28 Wm−2 K−1 and 0.94 Wm−2 K−1 at the cavity vacuum pressure of 0.001 Pa. The results suggest that a rise in cavity pressure from 0.001 Pa to 100 kPa increases the centre-of-pane and total U values from 0.28 Wm−2 K−1 and 0.94 Wm−2 K−1 to 2.4 Wm−2 K−1 and 2.58 Wm−2 K−1, respectively. The temperature descent on the surfaces of TVG between hot and cold sides increases by decreasing the cavity vacuum pressure from 50 kPa to 0.001 Pa. Nonevaporable getters will maintain the cavity vacuum pressure of 0.001 Pa for over 20 years of life span in the cavity of 10-mm wide edge-sealed triple vacuum glazing, and enable the long-term durability of TVG

Solar energy gain and space-heating energy supply analyses for solid-wall dwelling retrofitted with the experimentally achievable U-value of novel triple vacuum glazing

A considerable effort is devoted to devising retrofit solutions for reducing space-heating energy in the domestic sector. Existing UK solid-wall dwellings, which have both heritage values and historic fabric, are being improved but they tend to have meagre thermal performance, partly, due to the heat-loss through glazings. This paper takes comparative analyses approach to envisage space-heating supply required in order to maintain thermal comfort temperatures and attainable solar energy gains to households with the retrofit of an experimentally achievable thermal performance of the fabricated sample of triple vacuum glazing to a UK solid-wall dwelling. 3D dynamic thermal models (timely regimes of heating, occupancy, ventilation and internal heat gains) of an externally-insulated solidwall detached dwelling with a range of existing glazing types along with triple vacuum glazings are modelled. A dramatic decrease of space-heating load and moderate increase of solar gains are resulted with the dwelling of newly achievable triple vacuum glazings (having centre-of-pane U-value of 0.33 Wm-2 K-1) compared to conventional glazing types. The space-heating annual cost of single glazed dwellings was minimised to 15.31% (≈USD 90.7) with the retrofit of triple-vacuum glazings. An influence of total heat-loss through the fabric of solid-wall dwelling was analysed with steady-state calculations which indicates a fall of 10.23% with triple vacuum glazings compared to single glazings

Integrating knowledge management and orientation dynamics for organization transition from eco-innovation to circular economy

Purpose – This study focuses on establishing relations with some important but underestimated elements of knowledge dynamics and firm orientations to characterize organizational circular economy activities through eco-innovation (EIN). The advent of the circular economy (CE) in this post-pandemic era has brought unpredictable sustainable challenges for the manufacturing industries. This research paper aims to bring more clarity to the extant literature on the relationship between environmental innovation (EI) and CE.Design/methodology/approach – In this study, a systematic literature review methodology was used to research the determinants of EI in the knowledge environment that drives the implementation of a CE.Findings – This paper proposes a framework that articulates organizational learning and orientation dynamics and offers a new set of internal knowledge resources for a corporate CE. It is found that change toward CE requires connection with EI. However, successful CE growth largely depends on leveraging knowledge resources and orientation dynamics (stakeholder orientation, sustainability orientation, organization learning orientation and entrepreneurial orientation). CE techniques are still in their early phases of adoption and their implementation is still in its development. Circular knowledge economy (CKE) has the potential to be a useful alternative to achieving thriving CE to achieve sustainability in local and global businesses operations.Practical implications – This study helps companies to understand the organizational learning and different orientation dynamics for achieving CE principles. The research findings imply that EI is critical in establishing a sustainable transition toward CE through organizational learning and orientation dynamics and has garnered significant attention from academics, public policymakers and practitioners. The proposed framework can guide managers to develop sustainable policies related to the CE. This research recognizes that firm-level CKE is important in shaping how knowledge resources relate to CE within transition management literature.Originality/value – This paper abridges the knowledge gap in identifying key drivers and presents the current eminence, challenges and prognostications of sustainable EI parameters in the changingclimate of CE. This study builds a framework that combines insights from different viewpoints and disciplines and extends one’s understanding of the relationship between EI and CE. From a theoretical perspective, this study explains the knowledge management complexity links between EI and CE. It builds a theoretical bridge between EI and CE to illustrate how firms transition toward CE following the recommendations. Thus, researchers should continue to support their research with appropriate theories that have the potential to explain EI and CE relationship phenomena, with a particular emphasis on some promising but underutilized theories such as organizational learning, dynamic capabilities and stakeholder theorie

Integrating knowledge management and orientation dynamics for organization transition from eco-innovation to circular economy

Purpose This study focuses on establishing relations with some important but underestimated elements of knowledge dynamics and firm orientations to characterize organizational circular economy activities through eco-innovation (EIN). The advent of the circular economy (CE) in this post-pandemic era has brought unpredictable sustainable challenges for the manufacturing industries. This research paper aims to bring more clarity to the extant literature on the relationship between environmental innovation (EI) and CE. Design/methodology/approach In this study, a systematic literature review methodology was used to research the determinants of EI in the knowledge environment that drives the implementation of a CE. Findings This paper proposes a framework that articulates organizational learning and orientation dynamics and offers a new set of internal knowledge resources for a corporate CE. It is found that change toward CE requires connection with EI. However, successful CE growth largely depends on leveraging knowledge resources and orientation dynamics (stakeholder orientation, sustainability orientation, organization learning orientation and entrepreneurial orientation). CE techniques are still in their early phases of adoption and their implementation is still in its development. Circular knowledge economy (CKE) has the potential to be a useful alternative to achieving thriving CE to achieve sustainability in local and global businesses operations. Practical implications This study helps companies to understand the organizational learning and different orientation dynamics for achieving CE principles. The research findings imply that EI is critical in establishing a sustainable transition toward CE through organizational learning and orientation dynamics and has garnered significant attention from academics, public policymakers and practitioners. The proposed framework can guide managers to develop sustainable policies related to the CE. This research recognizes that firm-level CKE is important in shaping how knowledge resources relate to CE within transition management literature. Originality/value This paper abridges the knowledge gap in identifying key drivers and presents the current eminence, challenges and prognostications of sustainable EI parameters in the changing climate of CE. This study builds a framework that combines insights from different viewpoints and disciplines and extends one’s understanding of the relationship between EI and CE. From a theoretical perspective, this study explains the knowledge management complexity links between EI and CE. It builds a theoretical bridge between EI and CE to illustrate how firms transition toward CE following the recommendations. Thus, researchers should continue to support their research with appropriate theories that have the potential to explain EI and CE relationship phenomena, with a particular emphasis on some promising but underutilized theories such as organizational learning, dynamic capabilities and stakeholder theories

The influence of forced convective heat transfer on hybrid nanofluid flow in a heat exchanger with elliptical corrugated tubes : numerical analyses and optimization

The capabilities of nanofluids in boosting the heat transfer features of thermal, electrical and power electronic devices have widely been explored. The increasing need of different industries for heat exchangers with high efficiency and small dimensions has been considered by various researchers and is one of the focus topics of the present study. In the present study, forced convective heat transfer of an ethylene glycol/magnesium oxide-multiwalled carbon nanotube (EG/MgO-MWCNT) hybrid nanofluid (HNF) as single-phase flow in a heat exchanger (HE) with elliptical corrugated tubes is investigated. Three-dimensional multiphase governing equations are solved numerically using the control volume approach and a validated numerical model in good agreement with the literature. The range of Reynolds numbers (Re) 50 < Re < 1000 corresponds to laminar flow. Optimization is carried out by evaluation of various parameters to reach an optimal case with the maximum Nusselt number (Nu) and minimum pressure drop. The use of hybrid nanofluid results in a greater output temperature, a higher Nusselt number, and a bigger pressure drop, according to the findings. A similar pattern is obtained by increasing the volume fraction of nanoparticles. The results indicate that the power of the pump is increased when EG/MgO-MWCNT HNFs are employed. Furthermore, the thermal entropy generation reduces, and the frictional entropy generation increases with the volume fraction of nanoparticles and Re number. The results show that frictional and thermal entropy generations intersect by increasing the Re number, indicating that frictional entropy generation can overcome other effective parameters. This study concludes that the EG/MgO-MWCNT HNF with a volume fraction (VF) of 0.4% is proposed as the best-case scenario among all those considered.Taif University Researchers Supporting Granthttps://www.mdpi.com/journal/applsciMechanical and Aeronautical Engineerin