System-level key performance indicators for building performance evaluation

Quantifying building energy performance through the development and use of key performance indicators (KPIs) is an essential step in achieving energy saving goals in both new and existing buildings. Current methods used to evaluate improvements, however, are not well represented at the system-level (e.g., lighting, plug-loads, HVAC, service water heating). Instead, they are typically only either measured at the whole building level (e.g., energy use intensity) or at the equipment level (e.g., chiller efficiency coefficient of performance (COP)) with limited insights for benchmarking and diagnosing deviations in performance of aggregated equipment that delivers a specific service to a building (e.g., space heating, lighting). The increasing installation of sensors and meters in buildings makes the evaluation of building performance at the system level more feasible through improved data collection. Leveraging this opportunity, this study introduces a set of system-level KPIs, which cover four major end-use systems in buildings: lighting, MELs (Miscellaneous Electric Loads, aka plug loads), HVAC (heating, ventilation, and air-conditioning), and SWH (service water heating), and their eleven subsystems. The system KPIs are formulated in a new context to represent various types of performance, including energy use, peak demand, load shape, occupant thermal comfort and visual comfort, ventilation, and water use. This paper also presents a database of system KPIs using the EnergyPlus simulation results of 16 USDOE prototype commercial building models across four vintages and five climate zones. These system KPIs, although originally developed for office buildings, can be applied to other building types with some adjustment or extension. Potential applications of system KPIs for system performance benchmarking and diagnostics, code compliance, and measurement and verification are discussed

Low temperature thermochronology using thermoluminescence signals from quartz

Isothermal thermoluminescence (ITL) and thermoluminescence (TL) signals from quartz were studied. A single aliquot regenerative dose protocol has been applied for ITL De determination (SAR-ITL). In the SAR-ITL protocol, the preheat condition was a cutheat to 10 °C higher than measurement temperature. The test dose was approximate to the expected De, and a 450 °C heat was given at end of each cycle to minimize signal build-up. Based on signals strength and dose recovery test, temperatures of 235 and 255 °C were selected for the ITL De measurement. A multiple aliquots regenerative protocol has been applied for TL De determination (MAR-TL). The preheat procedure was a cutheat of 235 °C and a second glow TL of 175 Gy was used for normalization. The sensitivity change of first heating to 450 °C was negligible, supported by comparison between additive and regenerative dose growth curves. Based on the natural TL signal and preheat condition studies, De values at temperatures of 250–330 °C were used for thermochronological study. These two protocols were applied to rock samples collected at different elevations from Nujiang River (also called Salween River) valley slope. The SAR-ITL gave De results consistent with the MAR-TL at temperatures of 40–50 °C higher. The results clearly demonstrate the differences in the thermal histories between the analyzed samples. The SAR-ITL and MAR-TL protocols were both found to be suitable for application in thermochronology.postprin

Housing wealth and residential energy consumption

The housing wealth effect manifests as a positive relationship between consumption and perceived housing wealth. When the perceived value of a property rises, homeowners may feel more comfortable and secure about their wealth, causing them to spend more. This study adopts a behavioural approach to verify if this relationship holds true for residential energy consumption. An analytical framework is proposed to study the relationship between housing wealth and energy consumption at both the market and the individual level. We find evidence of significant association between housing wealth and energy consumption by using data between 1995 and 2016 from the UK. As the perception of housing value increases, UK residents tend to increase their energy consumption. Our models also consider psychological biases in energy consumption behaviours, such as market sentiment in the macro-level analysis and framing effect in the micro-level investigation. Our findings shed light on the behavioural aspects of housing wealth effect on residential energy consumption and demonstrate the potential of using behavioural interventions to encourage energy conservation activities. These findings are helpful in designing and implementing energy consumption policies that can strike a balance between social justice and economic efficiency.ESRC and NSF

Futher studies on the relationship between IRSL and BLSL at relatively temperatures for potassium-feldspar from sediments

In optical dating of potassium-feldspar, the luminescence signals can be stimulated by both infrared (IR) light and blue light (BL). To develop reliable dating methods using different stimulation light sources for feldspars, it is important to understand the sources of the traps associated with the infrared stimulated luminescence (IRSL) and blue light stimulated luminescence (BLSL) and their relationship. In this study, we explored the luminescence characteristics of IRSL and BLSL at different stimulation temperatures (from 60 °C to 200 °C) and their relationship based on five sets of experiments, i.e. post-IR BLSL, post-BL IRSL experiments, pulse annealing test, dose–response test and laboratory fading rate test. Our results suggest that the luminescence characteristics of IRSL and BLSL and their relationship are dependent on stimulation temperature. For IR stimulation at a relatively high temperature of 200 °C, at least two components of IRSL signals are involved in the process. One component of IRSL signals can be easily bleached by BL stimulation at 60 °C, while the other is relatively hard to be bleached by BL stimulation at 60 °C. The two components have different luminescence properties, such as thermal stability, dose–response and laboratory fading rate.postprin

Late Quaternary faulting on the Manas and Hutubi reverse faults in the northern foreland basin of Tian Shan, China

The Tian Shan Range lies in the actively deforming part of the India–Asia collision zone. In the northern foreland basin of Tian Shan, the strata were intensively deformed by Cenozoic folding and faulting. Slip rate studies along these faults are important for understanding the dynamics of crustal deformation and evaluating the seismic hazards in the region. Two reverse faults (the Manas and Hutubi faults) in the northern foreland basin were investigated. Due to past faulting events along these faults, the terrace treads along the Manas River were ruptured, forming fault scarps several meters in height. Loess deposits were trapped and preserved at the surface ruptures along these scarps. The thickness of the trapped loess is dependent on the size of the ruptures. The minimum and maximum ages of these scarps are constrained by dating the loess preserved at the surface ruptures and the terrace treads, respectively, using the quartz optically stimulated luminescence (OSL) dating technique. Our dating results suggest that the loess trapped at the ruptures was deposited from the early to mid-Holocene at the Hutubi Fault, and from the mid- to late-Holocene at the Manas Fault. The vertical displacements of the faults were evaluated by measuring the topographic profiles across the investigated fault scarps using the differential global position system (DGPS). Our results suggest that, during the late Quaternary in the studied region, the vertical slip rates of the Manas Fault were between ∼0.74mm/yr and ∼1.6mm/yr , while the Hutubi Fault had a much lower vertical slip rate between ∼0.34mm/yr and ∼0.40mm/yr . The tectonic implications of our results are discussed.postprin

Reply to comment by Huntley on "isochron dating of sediments using luminescence of K-feldspar grains"

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Experimental study of moderately reinforced concrete beams strengthened with bolted-side steel plates

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Shear transfer in bolted side-plated reinforced concrete beams

Reinforced concrete (RC) beams strengthened with bolted steel plates on their vertical faces are known as bolted side-plated (BSP) beams. The behaviour and performance of BSP beams are controlled by the arrangement of the steel plates and the interfacial slips caused by the shear deformation of anchor bolts due to shear force transfer. In this study, a nonlinear finite element model validated by available experimental results has been used to investigate the shear stress transfer in BSP beams. The effects of loading arrangements and the stiffnesses of RC beams, steel plates and bolt connections were investigated in detail by a parametric study. The results of this study shed light on the basic understanding of the internal shear transfer mechanism between steel plates and RC beams. A new design approach is also provided to help structural engineers in the determination of the shear transfer profile and the critical bolt shear force in the design of BSP beams.postprin

Human settlement of the last glaciation on the Tibetan plateau

An archaeological site with 19 handprints and footprints of Homo sapiens and the remnant of a fireplace have been found on hot spring travertine at an elevation of 4200 m on the Tibetan plateau. The prints were pressed on soft travertine by humans. The age of the prints and fireplace is estimated to be around 20,000 years using the optically stimulated luminescence method. The result suggests that humans came to the plateau much earlier than was previously thought. This evidence of human settlement implies that the Tibetans occupy high plateau much earlier than the Andeans and the ice sheet did not cover the entire Tibetan plateau during the Last Glacial Maximum.published_or_final_versio