Abstract

Covid-19 pandemic situation is forcing people to work from home due to lockdown; and as a result, there could be an effect on domestic energy consumption as well as carbon emission, particularly during winter. This paper investigates the change in energy demand, household budget and Carbon emission in upcoming winter of 2020/2021 due to the new patterns of working from home. The results show that a family with well insulated house that normally use a car or more to travel, will not be affected significantly in terms of their household budget; and the increase of carbon emission from heating will be compensated by the reduction in car use. For a family with poorly insulated house who do not travel long distances to work, the lockdown will cause more strain on their budget and they will be consuming more energy for heating and hence producing more carbon emission. The novel methodology implemented can be used to assess energy poverty and the effect of Covid-19 on households in other countries.

Abstract

COVID-19 pandemic brought economic crisis, also in the building sector, with an increase of energy consumption in the residential sub-sector due to the more intensive use. The strategic plans put in place by the European Union to face this crisis look to environmental sustainability, by identifying the building as a key sector. In Italy, it has been offered a tax deduction of 110% (divided into 5 annual quotas) aimed at promoting energy efficiency measures for existing buildings, also for fulfilling the new requirements of the Directive EU 844/2018. This investigation aims to analyse – from energy, environmental and economic points of view – this new funding program. It will be shown how it leads to prefer energy efficiency measures characterized by the best energy performance, and not by the best cost/benefit ratio.

Abstract

Car ownership significantly impacts the patterns in household consumption and time use. In this study, combining microdata from national expenditure survey and time use survey, carbon emissions of 85 daily household activities covering 24 hours in the day are estimated from a novel time-use perspective for Japanese households with and without private car ownership, respectively. Results indicate that while households with cars on average have higher emissions from transportation-related activities, their daily emissions from non-transportation activities are lower than households without cars. Policies targeting consumption behavior should therefore be devised based on the different activity emission patterns of different households.

Abstract

A novel pumped thermal energy storage (PTES) system with a heat pump (HP) and an Organic Rankine Cycle (ORC) is built and investigated at the Energie Campus Nürnberg, Germany. The basic idea is that surplus electricity available during the day is converted into heat with the HP and stored in a sensible hot water thermal storage. This enables a shift of e.g. photovoltaic electricity from day to night, as the stored heat can be converted back into electricity with the ORC at night. In order to examine the economic efficiency of the system, a dynamic simulation was set up using the AnyLogic simulation software. For a small community of 40 houses, it was shown that under current german market conditions, no economic use is possible without a significant cost reduction of the PTES. However, taking into account current trends in the development of feed-in tariffs in Germany, an economic use will be possible within the next few years.

Abstract

Energy generation and consumption is one of the most significant concerns for South Africa’s growing economy. Efforts to monitor the country’s overall energy consumption revealed that the industrial sector consistently consumes the highest energy at just under 60%. Policies are informed by an understanding of the current consumption across sectors and also the ability to predict future consumption. It is therefore important to understand the energy consumption of the highest energy user.
This research investigates the characteristics of industrial sector energy consumption, and how it has evolved between the years 1992 and 2018. The findings show that the total industrial consumption is still increasing. Contrary to global behavior, the local industrial consumption is still dominated by Coal; Electricity; Gas and Petroleum products respectively. High intensity industries are still heavily reliant on fossil fuel, regardless of the carbon footprint and GHG effect. This points to cost and availability influence on consumption. Although there is great potential in renewable energy, it is only low-intensive industries that are shifting to new non-conventional energy sources. Further work is required to define non-specified industrial subsectors as they contribute more than 10% to the total industrial consumption, compared to less than 5% in international consumption trends.

Abstract

The carbon dioxide (CO2) emission patterns of urban areas are likely to be closely associated with urban form. Using geographical information of Los Angeles County, this study examines potential linkages between urban form and CO2 emission patterns. For this purpose, we rely on the Local Climate Zones (LCZ) classification system, which is a universal framework for classifying urban areas into different categories according to their urban form characteristics. Our purpose is to see if there are any associations between types of LCZ and emission patterns. First, we developed the LCZ map for the county. Next, we obtained information related to residential and commercial building CO2 emissions across different neighborhoods from the official database of county. Next, we linked the emission data to the LCZ map to estimate per hectare and per capita emissions of each LCZ type. Results show that, in most cases, different LCZ types feature similar per capita emission patterns. This is, particularly, the case for commercial emissions. In terms of residential buildings, however, LCZ NO. 9 that refers to sparsely built development type exhibits significantly higher per capita emissions. This support common arguments regarding the environmental footprints of urban sprawl. Overall, results of this study indicate that the LCZ-based urban carbon mapping can provide useful insights into emission patterns of different urban forms. However, further research is needed to gain a more comprehensive understanding.

Abstract

The purpose of present paper is to investigate the flow and heat transfer characteristics of single smooth or dimpled sphere in the square channel by numerical simulation. Three-dimensional Navier-Stokes equations and SST k-ω turbulence model are adopted for the simulations. The effects of channel to particle diameter ratio and particle surface shape were discussed and presented in the present paper. It is found that, with the same inlet velocity and particle surface shape, when the ratio of channel to particle diameter is less than 4, as W/D decreases, the drag coefficient and Nusselt number increases rapidly. In addition, compared with smooth sphere particles, the presence of dimples decrease flow drag. Furthermore, at Re=29000, although there is little difference of Nusselt number between smooth and dimpled particles, the surface heat transfer characteristics of different particles are quite different.

Abstract

An effective battery thermal management system (BTMS) is of great significance to ensure safety and extend the service life for lithium-ion batteries (LIBs). In this paper, to obtain a more suitable operating temperature and a better temperature uniformity for the battery module, an ultrathin flat heat pipe-liquid cooling BTMS is proposed. The effect of different influence factors are investigated through the numerical simulation and the optimization is conducted on this basis. The results suggest that the heat can removed efficiently through the proposed BTMS, and the maximum temperature can be controlled below 43℃. Additionally, a variable heat pipe length scheme is proposed for the BTMS, which can significantly improve the temperature uniformity of the battery module. The average temperature difference can be controlled below 2℃ under the high discharge and current changing discharge process in comparison with the original system. The study facilitates a guideline for the optimization design of a BTMS.

Abstract

In this paper, a three-dimensional multi-phase non-isothermal numerical model is formulated to investigate the applicability of MF (metal foam) as flow distributor in AAEM (alkaline anion exchange membrane) fuel cell. The performance of the cell with MF flow field is compared with that of the cell with traditional channel-rib structure (serpentine channel flow field), the simulation results clearly show that using MF as flow distributor improves the performance greatly, and the improvement gets more and more obvious as the current density increases. The transport and distribution of water (including liquid water, membrane water, and water vapor) and reactants are analyzed to illustrate the performance improvement, and the analysis results agree with the conclusion.

Abstract

Air compressor is an important sub-component in fuel cell systems. Previous experimental and numerical studies still cannot provide an effective method for the quick and deep modification for fuel cell centrifugal compressor structure. To improve the compressor pressure ratio and efficiency, this paper develops a novel artificial intelligence (AI) framework for fuel cell centrifugal compressors by integrating three-dimensional (3D) computational fluid dynamics (CFD) models, machine learning and genetic algorithm. Based on the simulated results, the surrogate model is developed, which is subsequently coupled with NSGA-III algorithm to find the Pareto-optimal front. A set of optimized parameters are obtained. Based on the CFD model, the performance of the optimized compressor is comprehensively compared with the original compressor design. It is found that the flow uniformity inside compressor is greatly enhanced, leading to a better performance.