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Energy storage is an emerging technology that can enable the transition toward renewable-energy-based distributed generation, reducing peak power demand and the time difference between production and use. The energy storage could be implemented both at grid level (concentrated) or at user level (distributed). Chemical batteries represent the de facto standard of storage systems for performance and maturity; however, batteries feature a quite large environmental footprint and use precious raw materials. Mechanical storage technologies could represent a viable alternative to chemical batteries, because of their reduced impacts on the environment and on raw materials. This article presents the design of a motor/generator for a flywheel energy storage at household level. Three reference machines were compared by means of finite element analysis: a traditional iron-core surface permanent-magnet (SPM) synchronous machine, a synchronous reluctance machine (SynchRel), and an ironless SPM synchronous machine. Simulation shows that the ironless machine is good candidate for distributed energy storage, because of its high efficiency, high discharge duration, and low losses. A prototype ironless machine was designed and manufactured. Experiments confirm the simulation results.

State and local governments, businesses, community organizations, and the general public are taking an increasingly significant role in climate impact assessment. Driven by impacts to constituents and customers and threats to human health, essential services, and property values, local organizations are on the front lines of responding to climate change. National and international efforts such as the U.S. National Climate Assessment and Intergovernmental Panel on Climate Change provide fundamental scientific understanding as well as methods and modeling tools. Subnational climate assessments can build on this foundation and tailor models and analyses to specific local or decision contexts. However, subnational climate assessment and adaptation presents new scientific and research challenges, such as those related to downscaling climate models, simulating extreme events, and understanding local values and institutional practices. As state, local, and sectoral assessments become more common across the nation, there is a critical opportunity to share learnings and identify challenges and pitfalls. Building off a National Academies of Sciences, Engineering, and Medicine activity focusing exclusively on subnational climate assessment, we consider the methods and results from a variety of examples to synthesize findings about current practices and the future of subnational climate assessment.

Currently, a majority of global residential air-conditioning requirements are met using cooling systems based on the vapor compression cycle (VCC). To meet the future demand for space cooling and to reduce the corresponding environmental impact, there is a need for alternative cooling systems which require less resources and exhibit a higher coefficient of performance (COP). One of proposed alternatives is called the hybrid evaporative-vapor compression (HEVC) cycle, which utilizes adiabatic latent cooling in combination with the VCC. In this paper, we conducted a feasibility analysis of a HEVC system by comparing its performance to that of VCC for various global climates. To accomplish this, we developed and validated models to simulate the performance of residential VCC and HEVC systems. ASHRAE weather data and design conditions were then used to compare the performance of the two systems. In general, HEVC systems are best suited for hot arid climates with energy reduction greater than 20%. Conversely, humid climates are not suitable for HEVC adoption due to degraded performance of evaporative coolers in these climates. In addition to comparing the energy savings from HEVC systems, it is also critical to analyze their water consumption. Generally, climates that benefit the most from HEVC technology tend to also experience water scarcity issues. Thus, both the energy savings and water consumption of HEVC systems must be analyzed to guide the discussion on their adoption.

Energy storage is an emerging technology that can enable the transition towards renewable-energy-based distributed generation, reducing peak power demand and the time difference between production and use. The energy storage could be implemented both at grid level or at user level and nowadays different technologies are available for this purpose. In particular chemical batteries represent the de facto standard of storage systems for performance and maturity, however batteries feature a quite large environmental footprint and use precious raw materials. As an alternative to chemical batteries, mechanical storage technologies could be evaluated because of their reduced impacts on the environment and on the exploitation of raw materials. This paper presents the design, the prototyping and the experimental results of an ironless surface permanent-magnet (SPM) synchronous machine for a flywheel energy storage at household level. The electrical machine can work either as a motor or as a generator and it is the main item to fulfill the major challenges of a household application: high discharge duration and compatible size/dimension. The performance of the proposed ironless SPM machine are also compared with traditional iron core SPM synchronous machine by means of Finite Element Analysis (FEA).

Among the various transport modes aviation’s impact on climate change deserves special attention. Due to typical flight altitudes in the upper troposphere and above, the effect of aircraft engine emissions like e.g. water vapour, nitrogen oxides and aerosols on radiative forcing agents is substantial. The projected doubling of aircraft movements in the next 15 years will lead to an increase of aviation’s impact on climate and requires immediate mitigation options. Besides technological measures also new operational strategies are widely discussed; one of these concepts which has been subject of several studies in the past is Intermediate Stop Operations (ISO). It is based on the idea to reduce the stage length of flights by performing one or more intermediate landings during a mission. Here, we analyse the ISO concept by combining different models, which include a realistic traffic simulation taking into account operational constraints and ambient conditions, like e.g. wind, the calculation of engine emissions and the integration of a climate response model.We analyse the ISO concept for today’s worldwide aircraft fleet, including its influence on global emissions distributions as well as the impact on climate change by taking into account CO2 and non-CO2 effects, arising from contrail-cirrus, water vapour and nitrogen oxide emissions. We show in agreement with earlier findings that due to shorter flight distances the amount of fuel burnt over the mission can be reduced by roughly 5% on average globally. For the first time, we quantify the climate impact of ISO, where the flight trajectory is optimised for fuel use and the aircraft is not redesigned for the ISO procedure. We find an increased warming effect, which arises from nitrogen oxide and water vapour emissions, which are released at higher cruise altitudes and which over-compensate reduced warming effects from CO2 and contrail-cirrus. However, we expect a climate impact reduction for ISO even with existing aircraft, avoiding the higher flight altitude in the first flight segment and hence reducing the fuel savings. Thus, climate impact benefits could be achieved if lower fuel savings were acceptable. Moreover, this negative climate impact is found for the particular case of introducing ISO using the current wide-body fleet. It does not necessarily apply to the adoption of ISO using aircraft redesigned for a shorter range.

Data on metabolic rates (n = 0;81) and clothing insulation (n = 96) of school children and adolescents (A, primary school: age 9-10; B, primary school: age 10-11 year; C, junior vocational (technical) education: age 13-16 (lower level); D, same as C but at advanced level; and E, senior vocational (technical) education, advanced level: age 16-18) were collected (Diaferometer, Oxylog, Heart Rate derivation) during theory-, practical- and physical education- lessons. Clothing insulation was calculated from clothing weight, covered body surface area, and the number of clothing layers worn. Clothing insulation was found to be similar to that expected for adults in the same (winter) season, with minimal variation with age or school type (0.9 to 1.0 clo; 1.38 clo where coverall was worn), but more variation within groups (coefficient of variation 6-12%). Metabolic rate values (W.m-2) were lower than expected from adult data for similar activities, but are supported by other child data. The results of this study can be used to establish design criteria for school climate control systems or as general data on energy expenditure for children and adolescents. The results emphasize the need for specific child data and show the limited value of size-corrected adult data for use in children.