The aim of this paper is to research the parameters that optimize the thermal performances of a horizontal single-duct Earth to Air Heat eXchanger (EAHX). In this analysis, the EAHX is intended to be installed in the city of Naples (Italy). The study is conducted by varying the most crucial parameters influencing the heat exchange between the air flowing in the duct and the ground. The effect of the geometrical characteristics of the duct (pipe length, diameter, burial depth), and the thermal and flow parameter of humid air (inlet temperature and velocity) has been studied in order to optimize the operation of this geothermal system. The results reveal that the thermal performance increases with length until the saturation distance is reached. Moreover, if the pipe is designed with smaller diameters and slower air flows, if other conditions remain equal, the outlet temperatures come closer to the ground temperature. The combination that optimizes the performance of the system, carried... [more]

Nowadays, sustainable construction is a key factor for reaching net-zero emissions of carbon dioxide all over the world. This goal is impossible to achieve by merely reducing the energy consumption of end-users. A more holistic approach should be taken, adopting sustainable industrial practices that use environmentally friendly materials on a large scale. This paper presents the analysis of the hydrothermal properties of hemp thermal insulation plates. We carried out extensive measurements and the analysis of the thermal conductivity coefficient, drying-out dynamics, and water absorption. The study was performed with experimental insulation samples based on the fiber obtained from hemp stems, prepared using different adhesive powders. The dimensions of the analyzed samples were 300 × 300 mm. The proposed samples are not yet available in mass production. Hemp does not flower in the Baltic region and was traditionally used for soil regeneration. Thus, using this raw material increases th... [more]

In the face of severe air pollution and implementation of energy and climate policy, it remains a challenge to develop effective strategies addressing the problem of solid fuels use in single-family houses (SFH) in rural areas in Poland. This study investigated the correlations between thermal modernization of SFH, the changes of heat sources from coal to clean energy, including heat pumps driven by prosumers’ photovoltaic (PV) installation, and the disposable income of households in Polish rural areas. It also provided an analysis of the current support mechanisms promoting energy efficiency and PV development. The application of simulation modelling of energy consumption and costs in the research has proved that comprehensive thermal modernization of rural SFH constructed in the period of 1945−1970 and investments supporting PV/heat pump systems would enable the most cost-effective way of heating to be implemented. Considering that, today, spending on energy for heat puts a burden on... [more]

Energy efficiency is a key to reduced carbon footprint, savings on energy bills, and sustainability for future generations. For instance, in hot climate countries such as Qatar, buildings are high energy consumers due to air conditioning that resulted from high temperatures and humidity. Optimizing the building energy management system will reduce unnecessary energy consumptions, improve indoor environmental conditions, maximize building occupant’s comfort, and limit building greenhouse gas emissions. However, lowering energy consumption cannot be done despite the occupants’ comfort. Solutions must take into account these tradeoffs. Conventional Building Energy Management methods suffer from a high dimensional and complex control environment. In recent years, the Deep Reinforcement Learning algorithm, applying neural networks for function approximation, shows promising results in handling such complex problems. In this work, a Deep Reinforcement Learning agent is proposed for controlli... [more]

Energy efficiency measures and the deployment of renewable energy are commonly presented as two sides of the same coin—as necessary and synergistic measures to decarbonize energy systems and reach the temperature goals of the Paris Agreement. Here, we quantitatively investigate the policies and performances of the EU Member States to see whether renewables and energy efficiency policies are politically synergistic or if they rather compete for political attention and resources. We find that Member States, especially the ones perceived as climate leaders, tend to prioritize renewables over energy efficiency in target setting. Further, almost every country performs well in either renewable energy or energy efficiency, but rarely performs well in both. We find no support for the assertion that the policies are synergistic, but some evidence that they compete. However, multi-linear regression models for performance show that performance, especially in energy efficiency, is also strongly as... [more]

In recent years, cold food chains have shown an impressive growth, mainly due to customers life style changes. Consequently, the transportation of refrigerated food is becoming a crucial aspect of the chain, aiming at ensuring efficiency and sustainability of the process while keeping a high level of product quality. The recently defined Refrigerated Routing Problem (RRP) consists of finding the optimal delivery tour that minimises the fuel consumption for both the traction and the refrigeration components. The total fuel consumption is related, in a complex way, to the distance travelled, the vehicle load and speed, and the outdoor temperature. All these factors depend, in turn, on the traffic and the climate conditions of the region where deliveries take place and they change during the day and the year. The original RRP has been extended to take into account also the total driving cost and to add the possibility to slow down the deliveries by allowing arbitrarily long waiting times... [more]

Thermal processes represent a considerable part of the total energy consumption in manufacturing industry, in sectors such as steel, aluminium, cement, ceramic and glass, among others. It can even be the predominant type of energy consumption in some sectors. High thermal energy processes are mostly associated to high thermal losses, (commonly denominated as waste heat), reinforcing the need for waste heat recovery (WHR) strategies. WHR has therefore been identified as a relevant solution to increase energy efficiency in industrial thermal applications, namely in energy intensive consumers. The ceramic sector is a clear example within the manufacturing industry mainly due to the fuel consumption required for the following processes: firing, drying and spray drying. This paper reviews studies on energy efficiency improvement measures including WHR practices applied to the ceramic sector. This focuses on technologies and strategies which have significant potential to promote energy savin... [more]

This paper evaluates the potential energy savings when switchable insulation systems (SIS) are applied to walls of residential buildings located in Belgium and other locations in Europe. The study considers two low-energy prototypical dwellings (an apartment and a detached house) that are representative of post-2010 constructions and renovations in Belgium. Using an 3R2C-based analysis tool, the performance of both dwellings is evaluated with static and dynamic wall insulation systems. First, the switchable insulating system is described along with its associated simple 2-step rule-based control strategy. Then the modeling strategy and simulation analysis tools are presented. In Belgium, it was found that SIS-integrated walls allow energy savings up to 3.7% for space heating and up to 98% for cooling. Moreover, it was found that to further reduce the energy consumption of SIS-integrated buildings in various European climates, thermal mass placement needs to be considered. By optimizing... [more]

Motorized spindle system is one of the crucial components affecting the machine tools energy performance. Many previous studies have examined its energy optimization problems, however, most such studies focused mainly on parameters optimization to improve material removal energy efficiency or reduce total energy consumption. A missing research area is energy optimization problem considering thermal stability and productivity constraints simultaneously. Against this background, an energy optimization approach of motorized spindle system is presented with consideration of thermal stability and productivity adequately, with the goal of maximization of energy efficiency and material removal rate, and minimization of spindle average temperature which is closely associated with thermal stability. Firstly, the energy characteristics of motorized spindle and its cooling system are mathematically modelled. Then, a multi-objective optimization model is established to take the maximum energy effi... [more]

The construction sector is a great contributor to global warming both in new and existing buildings. Minimum energy buildings (MEBs) demand as little energy as possible, with an optimized architectural design, which includes passive solutions. In addition, these buildings consume as low energy as possible introducing efficient facilities. Finally, they produce renewable energy on-site to become zero energy buildings (ZEBs) or even plus zero energy buildings (+ZEB). In this paper, a deep analysis of the energy use and renewable energy production of a social dwelling was carried out based on data measurements. Unfortunately, in residential buildings, most renewable energy production occurs at a different time than energy demand. Furthermore, energy storage batteries for these facilities are expensive and require significant maintenance. The present research proposes a strategy, which involves rescheduling energy demand by changing the habits of the occupants in terms of domestic hot wate... [more]

The growing risk of climate change caused by the emission of greenhouse gases poses new challenges to contemporary countries. The development of economies is usually related to increasing levels of greenhouse gas emissions. Therefore, the question arises whether it is possible to achieve sustainable economic and financial development and simultaneously reduce greenhouse gas emissions. This paper assumes it is possible if energy efficiency is increased. The aim of the paper is to show the link between energy efficiency and sustainable economic and financial development in Organisation for Economic Co-operation and Development (OECD) countries for the period 2000−2018 by using data envelopment analysis (DEA) and regression analysis. The results show a slight upward trend of total factor energy efficiency (TFEE) in OECD countries for the analysed period; however, there is a difference in TFEE levels. Developed OECD countries have higher TFEE levels than developing OECD countries. The link... [more]

Metal cloth seals have been used increasingly in gas turbines due to their flexibility and superior leakage performance. Leakage performance of a metal cloth seal depends on operating conditions, slot and geometric dimensions. These parameters need to be investigated for the best leakage performance. In this study, pressure drop and critical geometric parameters of typical cloth seal form are investigated with an experimental setup. Slot depth, cloth width, sealing gap, shim thickness, surface roughness, pressure drop, offset and mismatch are selected parameters for the screening experiments. Sixteen experiments were conducted following a two-level Resolution IV fractional factorial experiment design for eight parameters. The results indicated that strong parameters for the leakage performance are pressure drop, cloth width, slot depth and offset. Leakage rate is increased with an increase in slot depth, gap, shim thickness, pressure drop and mismatch. During screening experiments, the... [more]

This paper qualitatively evaluates the application of blockchain technology for three energy efficiency use cases. To achieve the Sustainable Development Agenda, energy efficiency improvements have to double by 2030. However, the adoption of energy efficiency interventions is slow due to several market barriers. Blockchain technology is a nascent technology with the potential to address these barriers or even fundamentally change energy system designs, by enabling transparent, decentralised, and tamper-resilient systems. Nevertheless, a blockchain application comes with trade-offs and needs to be considered on a case by case basis. In this paper, we examine the benefits and constraints of a blockchain application for three different approaches to achieving energy efficiency: (i) peer-to-peer (P2P) energy trading; (ii) White Certificate Scheme (WCS); and (iii) Energy Service Companies (ESCOs). For each of these cases, we apply a decision framework to assess blockchain feasibility and ou... [more]

Energy efficiency is one of the most important topics nowadays. It is strictly related to energy demand, energy policy, environmental pollution, and economic issues. Energy efficiency can be increased and operating costs reduced by using waste heat from other processes. One of the possibilities is to use sorption chillers to produce chilled water and desalinated water. Low-temperature waste heat is not easy to utilize because of the low energy potential. Using adsorption chillers in low-temperature conditions allows utilizing waste heat and producing useful products in many regions of the world. The paper presents the results of an experimental study carried out on a three-bed adsorption chiller with desalination function, using silica gel and water as a working pair. The laboratory test stand included one evaporator, one condenser, and three separate tanks for water, desalinated water, and brine, respectively. The test stands scheme and description were presented. All results were obt... [more]

The current global population growth forecast carries with it a global increase in demand for food. In order to meet this demand, it is necessary to increase production, which requires an increase in energy consumption. However, forecasted energy production growth is insufficient and traditional sources of energy are limited; hence, it is necessary to strive for greater energy efficiency in food production systems. The study aimed to compare the economic energy efficiency of food production systems in selected countries and identify the sources of diversification in this field. As a measure of energy efficiency, the indicators of the energy intensity of food production were used in this study. To calculate these indicators, a method based on input-output life-cycle assessment assumptions was used, which enables researchers to obtain fully comparable results between countries. The study showed that despite an increase in energy consumption in the food production systems of the analyzed... [more]

Gun firing is a process that converts propellant chemical energy to projectile kinetic energy and other kinds of energies. In order to explore the energy conversion process, firstly, the interior ballistics mathematical model and the barrel-projectile finite element model are built and solved. Then, the related variable values and energy values are obtained and discussed. Finally, for improving energy efficiency, the interval uncertainty optimization problem is modeled, and then solved using the two-layer nested optimization strategy and back-propagation (BP) neural network surrogate model. Calculation results show that, after optimization, the heat efficiency raises from 31.13% to 33.05% and the max rifling stress decreases from 893.68 to 859.76 Mpa, which would improve the firing performance and prolong the lifetime of the gun barrel.

The residential, commercial, and public sectors consume between 20% and 30% of final energy demand worldwide. Due to the intensive use of fossil fuels and conventional electricity, they also have an important participation in the emission of greenhouse gases (GHG). Taking Mexico as a case study, this article develops an alternative scenario that considers that in these sectors, buildings can generate energy for self-consumption or to supply it to the power network—for which four solar energy options are analyzed. In addition, to manage and rationalize the energy demand of these buildings, eight energy efficiency measures are studied. These options were selected on the basis that they are technically and economically feasible to implement in buildings in Mexico. The results reveal that by 2030, in relation to the GHG trend scenario, this mitigation scenario reduces 23.5 million tons of carbon dioxide equivalent (MtCO2e) in the residential (19 MtCO2e), commercial (2.6 MtCO2e), and public... [more]

The future of business development relies on the effective management of risks, opportunities, and energy and water resources. Here, we evaluate the application of best practices to identify, analyze, address, monitor, and control risks and opportunities (R/O) according to ISO 31000 and 50000. Furthermore, we shed light on tools, templates, ISO guides, and international documents that contribute to classifying, identifying, formulating control, and managing R/O parameterization in a comprehensive management system model, namely CMS QHSE3+, which consists of quality (Q), health and safety (HS), environmental management (E), energy efficiency (E2), and other risk components (+) that include comprehensive biosecurity and biosafety. By focusing on the deployment of R/O-based thinking (ROBT) at strategic and operational levels, we show vulnerability reduction in CMS QHSE3+ by managing energy, efficiency, and sustainability.

The zero-energy building (ZEB) concept has a high potential for securing energy savings in the building sector. To achieve ZEB, various active systems, including renewable systems such as photovoltaic, solar heating, and geothermal systems, have been developed. However, the existing systems are costly or not optimized. To overcome these issues, the authors previously developed an integrated tri-generation system. In this research, the previously developed system was comprehensively analyzed considering the indoor thermal comfort and energy efficiency to develop a design and operation method for the integrated system. Two different heating systems (convective heating and radiant floor heating) were employed in the tri-generation system, and their system performance, predicted mean vote (PMV), and predicted percentage of dissatisfied (PPD) were compared using simulations. The results showed that the heating coefficient of power of the radiant floor heating system was 18.8% higher than th... [more]

The cost of solar PV has been reduced to a level such that the levelized cost of solar electricity is either cheaper or competitive relative to the grid electricity. So, a low-cost integration of solar PV with grid can be a cost-effective solution for clean cooking. The usual technique of using grid-tied inverters contribute ~20% towards the energy cost. The proposed system incorporates a control circuit that connects grid electricity to the solar PV via a DC link and provides a DC output eliminating the requirement of grid-tied inverters. Most of the cooking utensils either have a resistive heating element or an electronic control circuit that is insensitive to input AC or DC and no modification is needed for the cooking utensils while using with DC voltage. In the proposed system, preference for power delivery is always given to the solar PV and the grid effectively operates as the backup for the system when solar PV output fluctuates due to varying weather and climatic conditions. A... [more]

“Israeli Hope in Academia” is a program, designed by the president of the state of Israel, Reuven Rivlin. The program is based on the perception that Israeli society is changing, from having a clear majority and several minorities to a society comprised of four principal sectors that are roughly similar in size: secular Jews, religious Jews, Haredi (ultra-orthodox) Jews and Arabs. The program acts to encourage a more diverse and culturally competent higher education system that promotes partnership. One of the means to achieve that goal is to create meaningful educational interactions between people from academia and the younger generation of these sectors. Over the past year, students from various faculties in the Holon Institute of Technology (HIT) took part in a course called “Green Ambassadors”, which corresponds with the “Israeli Hope” program. This course was considered an action learning course, which is a course that combines academic learning and social involvement that has an... [more]

Sustainable development and the increasing demand for equitable energy use as well as the reduction of waste of energy are the author’s social and scientific motivations. This new paradigm is the selection of a pertinent methodology to evaluate the efficiency of habitat thermomodernization, which is one of the scientific tasks of the presented study. In order to meet the social and scientific requirements, 380 buildings from the end of the last century (made of large plate technology), which were thermally improved at the beginning of the XXI century, were designed for a comparative analysis of the predictive modelling of heating energy consumption. A specific set of important variables characterizing the examined buildings has been identified. Groups of variables were used to estimate the energy consumption in such a way as to achieve a compromise between the difficulty of obtaining them and the quality of forecast. To predict energy consumption, the six most appropriate neural method... [more]

This article addresses issues related to the quality of design and subsequent management of multi-family residential buildings in the context of their energy supply. The framework of the analysis carried out here are pro-environmental legal regulations currently in force in Poland. This article describes the impact of these regulations on the design process and the role of the designer. The requirements have been defined and the constraints have been identified. A number of factors directly related to the nature and parameters of the designed buildings and their location have been taken into consideration. On the basis of this study, the impact of legal regulations both on the method of energy supply in the buildings and on their later use and management have been presented. Positive and negative aspects of the analyzed regulations have been indicated and directions for their evaluation and optimization have been proposed. The research was carried out using real buildings, both complet... [more]

In central Italy, there are extensive European black pine (Pinus nigra Arn.) plantations which range from 30 to 60 years of age and where no thinning operations have been made. The main purpose of this study was to provide a comparative analysis of two cable yarder technologies (Maxwald, mobile pulley carriage and Savall, semi-automatic carriage), in terms of fuelwood production and cost, from the first thinning of a 33 year old plantation in slope areas of these plantations. The results showed that fuelwood production was cost-effective in both systems (Savall by 15.1 and Maxwald by 14.8 € m−3), although the productivity of the Savall system was higher than the Maxwald system (6.1 vs. 5.7 m3 h−1). The respect amounts of productivity have the potential to increase by 27% for the Savall yarder and 25% for the Maxwald yarder upon condition that the delay times are reduced to minimum level by proper training of workers, by a better organization, and planning of operations. The total effec... [more]

This paper identifies and characterizes the technical measures and policy instruments that can be used to promote energy efficiency and the use of renewable sources for domestic hot water (DHW). DHW presents a considerable potential for abatement of greenhouse gas emissions around the world. Measures were characterized in terms of level of transformation, impact and scope, among others. Policy instruments were characterized in terms of target groups, competences required for implementation, major challenges and nature of the instruments. A matrix showing the applicability of policy instruments per technical measure was derived, enabling policy makersto better choose articulated measures and policy instruments for their policy packs.