• Energy Research
• 2016-2025close
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Abstract Two office layouts with high and low levels of thermal control were compared, respectively traditional cellular and contemporary open plan offices. The traditional Norwegian practice provided every user with control over a window, blinds, door, and the ability to adjust heating and cooling. Occupants were expected to control their thermal environment to find their own comfort, while air conditioning was operating in the background to ensure the indoor air quality. In contrast, in the British open plan office, limited thermal control was provided through openable windows and blinds only for occupants seated around the perimeter of the building. Centrally operated displacement ventilation was the main thermal control system. Users’ perception of thermal environment was recorded through survey questionnaires, empirical building performance through environmental measurements and thermal control through semi-structured interviews. The Norwegian office had 35% higher user satisfaction and 20% higher user comfort compared to the British open plan office. However, the energy consumption in the British practice was within the benchmark and much lower than the Norwegian office. Overall, a balance between thermal comfort and energy efficiency is required, as either extreme poses difficulties for the other.

Abstract In the next 25 years an unprecedented number of new marine artificial structures, over 75,000 offshore wind turbines alone, are planned to meet global net zero targets. Structures are required to last for multiple decades in the hostile marine environment; where the largest cost across their whole lifecycle is on operations and maintenance dependent on accessibility in calm seas. However, the role of climate change on accessibility, and thus operational cost, has not been resolved. Here we provide the first study of future accessibility; evaluated from global climate model driven wave modelling, using the high emission scenario (RCP8.5). We found that climate change drives significant regional variation in accessibility, with the northern hemisphere benefiting from a 6% increase in operating windows whilst accessibility in parts of the southern hemisphere is reduced by 6-9%. These findings will help offshore developers and stakeholders incorporate adaptions to climate change as part of strategic planning practices.

In the quest for more efficient solar thermal systems, accurately determining the thermal emittance of low-emissive materials is crucial in determining the power losses. This paper describes the calorimetric method designed to precisely measure the thermal emittance of Selective Solar Absorbers (SSAs) to be used in High Vacuum Flat Plate Collectors (HVFPCs). The method’s capability is demonstrated through the successful correction of thermal emittance values for copper samples of varying sizes, including dimensions down to 49 cm2. Results highlight the method’s potential to significantly reduce measurement errors associated with small-size and/or low-emittance samples, providing a path forward to improve the design and efficiency of SSAs. This research marks a significant step in advancing solar thermal technology by enabling emittance measurements with a precision better than 0.003, which is essential for the development of high-performance solar thermal absorbers. The method has also been applied to correct the thermal emittance value of SSA measured in previous measurement campaigns, and it allows a better estimation of the SSA efficiency conversion curve.

Abstract Persistent luminescence (PersL), also called long-lasting phosphorescence or simply afterglow, is a luminescence characterised by the emission of radiation from a few seconds to several days after the excitation source has been switched off. Over the past two decades, research on PersL materials, both in fundamental and applied physics, has developed rapidly; however, the explanation for the physical processes that cause afterglow still needs to be clarified. Today, PersL materials are used mainly for luminescent paints, safety signs and decorations. At the same time, research into using such materials in medicine, information storage, anti-counterfeiting technology, etc., is underway. Currently, information on the long persistent luminescence materials with emission in the blue and green spectral range is widely available. In contrast, the number of publications on the afterglow in the red and near-infrared spectral range is considerably lower. Within the framework of this research, Mg2SiO4: Mn2+; M3+ (M3+ = B3+; Al3+; Ga3+; In3+) materials were synthesised using solid state reaction synthesis. When excited with X-rays, the materials exhibited a broad Mn2+ PersL band with two maxima at approximately 625 nm and 730 nm. After cessation of irradiation, an afterglow of at least 6 hours could be observed. The research focuses on the trap properties of the materials. It was concluded that at least three discrete trap levels with activation energies approximately between 0.4–1.6 eV were present in the samples. Additionally, co-doping with Al3+; Ga3+; In3+ ions improved PersL longevity of the Mg2SiO4: Mn2+ material.

Most of the world’s mountain glaciers have been retreating for more than a century in response to climate change. Glacier retreat is evident on all continents, and the rate of retreat has accelerated during recent decades. Accurate, spatially explicit information on the position of glacier margins over time is useful for analyzing patterns of glacier retreat and measuring reductions in glacier surface area. This information is also essential for evaluating how mountain ecosystems are evolving due to climate warming and the attendant glacier retreat. Here, we present a non-comprehensive spatially explicit dataset showing multiple positions of glacier fronts since the Little Ice Age (LIA) maxima, including many data from the pre-satellite era. The dataset is based on multiple historical archival records including topographical maps; repeated photographs, paintings, and aerial or satellite images with a supplement of geochronology; and own field data. We provide ESRI shapefiles showing 728 past positions of 94 glacier fronts from all continents, except Antarctica, covering the period between the Little Ice Age maxima and the present. On average, the time series span the past 190 years. From 2 to 46 past positions per glacier are depicted (on average: 7.8).