Factors influencing the performance parameters of vacuum glazed smart windows to net zero energy buildings

Abstract

The progression of smart technologies such as vacuum glazed windows are considered a realistic achievement of the net energy zero buildings (NZEBs). From designers to researchers to builders, there has been an increasing concern about understanding the inter-dependencies between the parameters and influencing factors that determine the performance of vacuum glazed smart windows. This research reviews the performance parameters such as thermal transmittance (U value), thermal resistance (R value), solar transmittance (g value), visible light transmittance (v value) and thermal resistance of residual gas space (Rgas value). These are interdependent on factors such as edge seal, support pillar array, low emittance coatings, getters, and effective evacuation process. This research implicates that effective hermetic edge seal provides longevity such as fusion and solder glass edge sealed vacuum glazing could be cost-effective and energy efficient solution. Stainless steel support pillar array is an unavoidable compromise on U value. This review shows that an increase of the size of glass sheet increases support pillar array improving the overall U value. Also, an addition of low emittance coatings enhances U value whilst maintaining v value. To improve the overall life span of the vacuum glazed smart window, an incorporation of combo-getter that absorb any gases released from the internal glass surfaces in to into the vacuum cavity from the glass surface which prevents degradation of vacuum pressure and provide long term vacuum pressure stability in the vacuum glazed smart window. A recent improvement in the understanding of evacuation process shows that hot-plate surface heat induction of 60˚C improved the vacuum pressure and mitigates the pump-out hole sealing process whilst lessening the temperature induced stresses.

Analysis of indoor environment and insulation performance of residential house with double envelope vacuum insulation panels

“…At the production level, advancements in vacuum sealing materials are critical in leading vacuum insulation panels [4,5], smart vacuum windows [6,7], and solar thermal evacuated flat plate collectors [8,9]. A vacuum insulation is a decreased quantity of atmospheric-air gap between two glass panes [10,11]. The amount of vacuum pressure is determined by the rate at which the density of air in a space decrease.…”

Enhancing the renewable energy payback period of a photovoltaic power generation system by water flow cooling

“…This reality could necessarily transition our built environment, such as office buildings and residential buildings, towards renewable energy sources [3,4]. As the concept of GEB (Generating Energy Buildings) has now becoming a reality in which a series of innovative technologies such as translucent vacuum insulation panels [5][6][7], smart vacuum insulated windows [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], vacuum-based PV integrated solar thermal collectors [26,27] and cooling mechanism [28], wind & wave energy systems [29], providing access 74 and monitoring of the electric vehicles charging [30][31][32][33][34] with integration to microgrid [35] and utilising waste heat into electricity using thermoelectric [36][37][38][39] are the progress towards smart cities. It is evident from the aforementioned references that solar thermal energy and insulation technologies are playing major role in achieving the built environment sector towards net-zero energy.…”

Predictive permanent magnet synchronous generator based small-scale wind energy system at dynamic wind speed analysis for residential net-zero energy building

“…The British Government revised the Climate Change Act in 2019 to commit the UK to reach net-zero emissions by 2050, up from an earlier aim of an 80% reduction in emissions by 2050 [3]. As a result, attaining net-zero energy building is critical and requires several progressive technologies such as vacuum glazing [6][7][8][9][10][11][12], triple vacuum glazing [13][14][15][16][17][18][19][20][21][22][23], and translucent vacuum insulation panel [24][25][26] to minimize heat loss or cooling loss through the building fabric. For hot water, the use of solar thermal collectors [27], and nowadays the use of advanced vacuum based photovoltaic thermal collectors [28] with thermoelectric generator for harvesting waste heat energy into useful electrical energy [29][30][31][32], these provide hot water and electrical energy generation throughout a year at higher thermal and electrical efficiency.…”