This paper presents the results of research on the preparation and use for energy purposes of three reed herbaceous energy plants: reed (Phragmites australis) and bulrush (Typha); both grown in local vicinities on lakes and riverbanks and reed canary grass (Phalaris arundinacea L.). The physical-mechanical characteristics (density, moisture, and ash content) of chopped and milled reeds were investigated. The investigation of mill fractional compositions determined the largest amount of mill—reed mill, collected on the sieves of 0.63 mm (40.0%). The pellet moisture ranged from 10.79% to 6.32%, while the density was 1178.9 kg m−3 for dry matter (DM) of reed. The ash content of reed, bulrush and reed canary grass pellets was 3.17%, 5.88%, and 7.99%, respectively. The ash melting temperature ranged from 865 to 1411 °C; these temperatures were high enough for ash melting. The determined pellet calorific value varied from 17.4 to 17.9 MJ kg−1 DM. The disintegration force, indicating pellet s... [more]

This research presents the development of R463A refrigerant, a nonflammable refrigerant that was retrofitted to replace R404A. R463A is primarily composed of hydrofluorocarbons/hydrocarbons/carbon dioxide (HFCs/HCs/CO2), and has global-warming potential (GWP) of 1494. It is a nonazeotropic mixture of R32 (36%), R125 (30%), R134a (14%), R1234yf (14%), and R744 (6%). R463A is composed of polyol ester oil (POE), and it is classified as a Class A1 incombustible and nontoxic refrigerant. R463A has a higher cooling capacity (Qe) than that of R404A, as it is composed of hydrofluorocarbons (HFCs) R32 and carbon dioxide (CO2) R744, and has lower GWP than that of R404A due to the use of hydrofluoroolefins (HFOs) from R1234yf. The results of this research showed that R463A can be retrofitted to replace R404A due to its composition of POE, Class A1 incombustibility, and lower toxicity. The properties of R463A and R404A, as analyzed using national institute of standards and technology (NIST) refere... [more]

Due to the increasing energy crisis and environmental pollution, the development of drive motors for new energy vehicles (NEVs) has become the focus of popular attention. To improve the sine of the air-gap flux density and flux regulation capacity of drive motors, a new hybrid excitation synchronous motor (HESM) has been proposed. The HESM adopts a salient pole rotor with built-in dual-V permanent magnets (PMs), non-arc pole shoes and excitation windings. The fundamental topology, operating principle and analytical model for a magnetic field are presented. In the analytical model, the rotor magnetomotive force (MMF) is derived based on the minimum reluctance principle, and the permeance function considering a non-uniform air-gap is calculated using the magnetic equivalent circuit (MEC) method. Besides, the electromagnetic performance including the air-gap magnetic field and flux regulation capacity is analyzed by the finite element method (FEM). The simulation results of the air-gap ma... [more]

Shale oil exploration has been a key area of onshore oil and gas exploration in China in recent years. In this study, organic geochemistry and element geochemistry are united to study the shale oil and source rock in the Lucaogou formation of Jimusar sag, in order to reveal the paleoclimate, paleoenvironment, source of organic matter, and factors affecting organic matter accumulation and shale oil generation. The shale oil in the study area is mainly accumulated in two strata with good reservoir properties and oiliness, known as the upper sweet spot and lower sweet spot. Indexes of biomarkers and sensitive elements revealed the warm and semi-arid paleoclimate during Lucaogou formation, and the water column was brackish to salty. Water stratification caused a suboxic to anoxic environment in the deep-water column and coincided with the anoxic photic zone phenomenon. Compared with the lower sweet spot, the more humid climate, deeper and fresher water, and stronger water stratification ch... [more]

The authors studied the impact of indoor air humidity in the range of 60% to 90% on building user perception in the temperature range of 26 to 28 °C. The research thesis was put forward that the impact of humidity on indoor air quality dissatisfaction of building users in a warm and humid indoor environment is greater than that indicated in thermal comfort models. The presented experiment examined the indoor air quality perception of n = 28 subjects in the test chamber of a nearly zero energy building under ten environmental conditions, together with a thermal comfort assessment. The authors developed an experimental relation for predicting building users’ satisfaction based on the Weber−Fechner law, where the predicted percentage of dissatisfied users (PD) is determined by means of air enthalpy (h), PD = f(h). The obtained results confirmed the sated thesis. Additionally, the intersection points of the experimental function and isotherms resulting from the Fanger model are presented,... [more]

Street lighting plays a crucial role in a city’s night landscape and in urban traffic management, influencing users’ comfort and safety. To contain costs of public street lighting systems and to avoid energy waste, illuminance levels on road surfaces must be adequate to fit actual traffic volumes, as prescribed by regulations. This is true not only for motorized roads but also for sidewalks, paths, and pedestrian areas. Regulations in force establish a relationship between road traffic volumes and minimum illuminance levels through the lighting classes selection procedure. Lighting classes selection is based on various para meters among which traffic volume is the most difficult to evaluate because traffic volumes are generally estimated or measured by a traffic observation campaign. In this paper, an alternative method for classes association which is based on a space syntax approach, is described. The method was applied to the case study town of Pontedera (Italy) for the analysis of... [more]

The production of energy in wind power plants is regarded as ecologically clean because there being no direct emissions of harmful substances during the conversion of wind energy into electricity. The production and operation of wind power plant components make use of the significant potential of materials such as steel, plastics, concrete, oils, and greases. Energy is also used, which is a source of potential negative environmental impacts. Servicing a wind farm power plant during its operational years, which lasts most often 25 years, followed by its disassembly, involves energy expenditures as well as the recovery of post-construction material potential. There is little research in the world literature on models and methodologies addressing analyses of the environmental and energy aspects of wind turbine modernization, whether in reference to turbines within their respective lifecycles or to those which have already completed them. The paper presents an attempt to solve the problems... [more]

Developing a regional power system to achieve a high level of integration of national systems requires sufficient development of the regional transmission grid. This is possible only with appropriate schemes for the complete cost−benefit analyses, and cost allocation of these transmission investments, which plays a critical role in the selection of the most efficient network investment and the proper assignment of their cost to the national systems. Network reinforcements affect the operation of power systems and, therefore, the externalities of power generation. This paper examines the impacts of integrating local air pollution damage from power production within the benefit assessment and cost allocation of transmission investments. The paper describes the methodology followed and illustrates its application in a real-life case study where a simplified version of a European network is considered. Within this case study, we have assessed the impact of considering the reduction in air... [more]

In this paper, a novel combined radiation-convection floor heating system is shown. This study uses practice-based learning and investigated the thermal performance of a combined radiation-convection floor heating system with a water heat pump system by evaluating the thermal environment and energy consumption in an experimental test. A new method that analyzed the thermal performance of four different controls was developed and applied. The results of the surface temperature distributions demonstrated that Mode 1, which uses only convection, had the lowest floor temperature and was thus considered inappropriate for occupants who sleep on the floor. By contrast, Modes 2, 3, and 4 showed high floor surface temperatures as hot water was supplied to the radiant heating panel. The predicted mean vote (PMV) results suggest that radiant floor heating is not appropriate for intermittent heating. In other words, occupants of single residences who return home at night will experience a long per... [more]

This article presents the results of an eco-efficiency assessment of the application of large-scale rechargeable battery technology in electricity generation from coal. The eco-efficiency of electricity production in a 350 MW coal-fired power plant was calculated. Two production variants were compared: with the use of a lithium-ion battery of a 400 MWh capacity to optimize the operation of power blocks and without using the battery. Hard coal is one of the main fossil fuels used to generate electricity in Poland. Despite the growing share of electricity from renewable sources, this situation will persist for many more years. The main reasons for this are the high costs and long-lasting process of moving away from fossil fuels in the energy sector. Therefore, any technical solutions that can temporarily reduce the negative impact of coal-based power engineering on the environment should be considered. At the same time, the economic aspects of such solutions must be taken into account. T... [more]

In order to assess the merits of national climate change mitigation policies, it is important to have a reasonable benchmark for how much human-caused global warming would occur over the coming century with “Business-As-Usual” (BAU) conditions. However, currently, policymakers are limited to making assessments by comparing the Global Climate Model (GCM) projections of future climate change under various different “scenarios”, none of which are explicitly defined as BAU. Moreover, all of these estimates are ab initio computer model projections, and policymakers do not currently have equivalent empirically derived estimates for comparison. Therefore, estimates of the total future human-caused global warming from the three main greenhouse gases of concern (CO2, CH4, and N2O) up to 2100 are here derived for BAU conditions. A semi-empirical approach is used that allows direct comparisons between GCM-based estimates and empirically derived estimates. If the climate sensitivity to greenhouse... [more]

Energy consumption and pollutant emissions from buildings have caused serious impacts on the environment. Currently, research on building environmental costs is quite insufficient. Based on life cycle inventory of building materials, fossil fuel and electricity power, a calculating model for environmental costs during different stages is presented. A single-objective optimization model is generated by converting environmental impact into environmental cost, with the same unit with direct cost. Two residential buildings, one located in Beijing and another in Xiamen, China, are taken as the case studies and analyzed to test the proposed model. Moreover, data uncertainty and sensitivity analysis of key parameters, including the discount rate and the unit virtual abatement costs of pollutants, are also conducted. The analysis results show that the environmental cost accounts for about 16% of direct cost. The environmental degradation cost accounts for about 70% of the total environmental c... [more]

Carbon dioxide phase transition fracturing has been widely used in rock mass excavation under complex environments, and its special rock breaking process shows obvious gathering energy effect. In this paper, the gathering energy effect of this technology is considered and then the impact reduction coefficient is defined and determined. Eventually, a combined method of field tests and numerical simulations is used to study the crack propagation characteristics and spatiotemporal changes of dynamic response. The results show that the cracks grow more and more slowly as time goes by; the peak displacement and peak point velocity in the primary impact direction are both greater than those in the secondary impact direction. The peak point velocity in different directions decreases as the distance from borehole increases and it decays more and more slowly. With the increase of distance from the borehole, the peak effective stress in the primary impact direction constantly decreases. However,... [more]

The complexity of power systems is rising mainly due to the expansion of renewable energy generation. Due to the enormous variability and uncertainty associated with these types of resources, they require sophisticated planning tools so that they can be used appropriately. In this sense, several tools for the simulation of renewable energy assets have been proposed. However, they are traditionally focused on the simulation of the generation process, leaving the operation of these systems in the background. Conversely, more expert SCADA operators for the management of renewable power plants are required, but their training is not an easy task. SCADA operation is usually complex, due to the wide set of information available. In this sense, simulation or co-simulation tools can clearly help to reduce the learning curve and improve their skills. Therefore, this paper proposes a useful simulator based on a JavaScript engine that can be easily connected to any renewable SCADAs, making it pos... [more]

Sustainable urban transport is fundamental not only for economic growth but also for the environmental protection, thus all logistics activities within the cities should be organized in a way to be environmentally friendly. The article aims at presenting the environmental sustainability of city logistics measures from different stakeholder perspectives. In the paper, a multi-method approach was implemented: literature review, text analysis, text mining, and statistical analysis. The paper presents how the stakeholders perceive urban logistics, if they see the need for coordination of its elements, who should be responsible for it, and what areas are the most important for them. The main task of this study is to recognize the priorities of different stakeholders. In consequence, the final effect of this article is an insight that is valuable not only for the local authorities but for many stakeholders, groups operating within the city that are and in many cases cooperating within the fr... [more]

The paper presents a review of the geological and hydrogeological data of the Lower Cretaceous aquifer in the Polish Lowlands and discusses the possibilities for the utilisation of geothermal water resources in existing and new district heating systems. Based on experience related to the use of thermal waters in existing geothermal systems, and using data from the literature, assessments have been made of the energy and environmental effects of the application of low-enthalpy geothermal resources from the Lower Cretaceous aquifer as a source of heat for urban district heating systems. The authors concluded that the implementation of such solutions could result in the production of approximately 4 PJ of geothermal energy annually. To date, these resources have only been developed in three locations—Mszczonów, Uniejów and Poddębice—with the total amount of energy generated annually reaching 100 TJ/year. Similar district heating networks in 120 nearby localities have been also identified.... [more]

Farming systems need to be planned to provide suitable levels of economic profitability and, at the same time, ensure an effective energy use, in order to perform environmentally friendly production strategies. The herein present work aims to assess the efficiency of energy use and economic impacts of the main farming methods (conventional, organic and integrated) of Clementine’s crops in Calabria (South Italy), through a combined use of Life Cycle Energy Assessment (LCEA) approach and economic analysis. For this purpose, data were collected from clementine producers by using face-to-face interviews. The results revealed that average energy consumption in the organic farming systems was 72,739 MJ, lower than conventional and integrated systems equal to 95,848 MJ and 94,060 MJ, respectively. This is mainly due to the ban of chemicals. Economic analysis showed that organic farms were more profitable compared with the other farming methods, because of the greater selling price and the EU... [more]

The paper presents the results of a study on chemical composition of ashes from three types of waste biomass in terms of fertilizer usefulness. Waste from the process of corn grain drying, including corn cobs, corn grains and corn husk and their mixtures in the ratio 4:1 (v/v) were examined. The study proved that corn grain was the material with the highest concentration of macroelements among those studied (P—21,452 ppm, K—25,970 ppm, S—5911 ppm) and the mixture of corn cobs with corn grains (Ca—81,521 ppm). When microelements were considered, the highest concentration was recorded for corn cobs (Cu—207 ppm, Mn—844 ppm, Zn—857 ppm) and corn husk (Fe—15,100 ppm). The analysis of toxic elements in the ashes of the biomass studied showed their highest concentration in corn husk ash (Ni—494 ppm, Cr—301 ppm, Pb—42.7 ppm, As—4.62 ppm). The analysis showed that regardless of the type of biomass studied, all ashes were strongly enriched (in relation to the average soil content) with phosphoru... [more]

Neighboring stand-alone hybrid microgrids with diesel generators (DGs) as well as grid-feeding photovoltaics (PV) and grid-forming battery storage systems (BSS) can be coupled to reduce fuel costs and emissions as well as to enhance the security of supply. In contrast to the research in control and small-signal rotor angle stability of microgrids, there is a significant lack of knowledge regarding the transient stability of off-grid hybrid microgrids in a cluster environment. Therefore, the large-signal rotor angle stability of pooled microgrids was assessed qualitatively and also quantitatively in this research work. Quantitative transient stability assessment (TSA) was carried out with the help of the—recently developed and validated—micro-hybrid method by combining time-domain simulations and transient energy function analyses. For this purpose, three realistic dynamic microgrids were modelled regarding three operating modes (island, interconnection, and cluster) as well as the conv... [more]

Decarbonization of energy-intensive systems (e.g., heat and power generation, iron, and steel production, petrochemical processes, cement production, etc.) is an important task for the development of a low carbon economy. In this respect, carbon capture technologies will play an important role in the decarbonization of fossil-based industrial processes. The most significant techno-economic and environmental performance indicators of various fossil-based industrial applications decarbonized by two reactive gas-liquid (chemical scrubbing) and gas-solid CO2 capture systems are calculated, compared, and discussed in the present work. As decarbonization technologies, the gas-liquid chemical absorption and more innovative calcium looping systems were employed. The integrated assessment uses various elements, e.g., conceptual design of decarbonized plants, computer-aided tools for process design and integration, evaluation of main plant performance indexes based on industrial and simulation r... [more]

Globally, the use of electric vehicles, and in particular the use of electric buses, has been increasing. The city of Nanjing leads China in the adoption of electric buses, supported by city policies and infrastructure. To lower costs and provide a better service, vehicle selection is crucial, however, existing selection methods are limited. Accordingly, Nanjing Bus Company developed a test method based on road tests to select a bus. This paper presents a detailed description of the test method and a case study of its application. The method included an organization structure, selection of eight test vehicles (four 10 m length, four 8 m length) from four brands (a total of 32 test vehicles), selection of indicators and selection of routes. Data was collected from repeated drives by 65 drivers over an 8-week period. Indicators included power consumption, charging duration, failure duration and driving distance. It is concluded that the road test method designed and conducted by the Nanj... [more]

The production cost of greenhouse cultivation depends mainly upon significant amounts of energy consumption in order to keep the optimum environmental condition for plant growth. Τhe expenditure on energy, either for heating or cooling, ranges between 30% to 60% of the total production costs, and any attempt to save energy will result in a positive effect on the potentiality of production accordingly, affecting the greenhouse product prices. Research has shown that CO2 enrichment in greenhouses significantly increases the yield of most indoor cultivation of plants of the C3 category. For these plants, when the CO2 concentration increases by three times above that of the atmosphere (380 ppm), the optimum plant growth temperature shifts higher by 5 °C to 10 °C reaching up to 30 °C to 32 °C. Therefore, huge amounts of solar energy can be captured inside the greenhouses, as the ventilation can be decreased. Alongside this, the use of a simple passive solar system consisting of plastic slee... [more]

The article presents the results of a study aiming to select the optimal source of heat for a newly designed single-family home. Commercial software was used to compare heating and ventilation systems involving a bituminous coal boiler, a condensing gas boiler, a biomass boiler, a heat pump with water and glycol as heat transfer media. The effectiveness of natural ventilation, mechanical ventilation with a ground-coupled heat exchanger, and solar heater panels for water heating were evaluated. The analysis was based on the annual demand for useful energy, final energy, and non-renewable primary energy in view of the pollution output of the evaluated heating systems. The analysis revealed that the heat pump with water and glycol was the optimal solution. However, the performance of the heat pump in real-life conditions was below its maximum theoretical efficiency. The biomass boiler contributed to the highest reduction in pollutant emissions (according to Intergovernmental Panel on Clim... [more]

Heat is usually transported by hydraulic circuits where the working medium is circulated by an electric pump. Heat can also be transferred by natural convection in passive systems. Passive systems where heat is transported downward have also been described and studied in the literature. These types of devices are referred to as reverse thermosiphons. However, systems of the type are not widely applied in practice due to the problems associated with the selection of the optimal working medium. In water-based thermosiphons, negative pressure is produced when water temperature falls below 100 °C, and non-condensable gas can enter the system. These problems are not encountered in systems where the working medium has a low boiling point. However, liquids with a low boiling point can be explosive, expensive, and harmful to the environment. The solution proposed in this paper combines the advantages of water and a liquid with a low boiling point. The described system relies on water as the he... [more]

The use of forest biomass for bioenergy in Australia represents only 1% of total energy production but is being recognized for having the potential to deliver low-cost and low-emission, renewable energy solutions. This review addresses the potential of forest biomass for bioenergy production in Australia relative to the amount of biomass energy measures available for production, harvest and transport, conversion, distribution and emission. Thirty-Five Australian studies on forest biomass for bioenergy are reviewed and categorized under five hierarchical terms delimiting the level of assessment on the biomass potential. Most of these studies assess the amount of biomass at a production level using measures such as the allometric volume equation and form factor assumptions linked to forest inventory data or applied in-field weighing of samples to predict the theoretical potential of forest biomass across an area or region. However, when estimating the potential of forest biomass for bioe... [more]