Drying is an extremely energy-intensive process. Superheated steam as a drying medium can improve the energy efficiency of the drying processes. In superheated steam drying, waste heat can be recovered by condensing the exhaust steam or raising its specific enthalpy. Spray drying is widely used in industry, even though its energy efficiency is often low. Substitution of air by superheated steam as a drying medium in a spray dryer may reduce the energy consumption of the drying process by 20−30%; moreover, if excess steam generated by moisture evaporation is upgraded to a higher temperature level and reused for drying, the energy demand could be decreased by even 80%. A literature review showed that superheated steam spray drying was successfully applied for both thermally resistant and a wide range of thermally sensitive materials. Superheated steam drying gives a number of advantages in terms of product properties, i.e., higher particle porosity due to rapid moisture evaporation resul... [more]

Natural gas is a fossil fuel that has been widely used for various purposes, including residential and industrial applications. The combustion of natural gas, despite being more environmentally friendly than other fossil fuels such as petroleum, yields significant amounts of greenhouse gas emissions. Therefore, the optimization of natural gas consumption is a vital process in order to ensure that emission targets are met worldwide. Regarding residential consumption, advancements in terms of boiler technology, such as the usage of condensing boilers, have played a significant role in moving towards this direction. On top of that, the emergence of technologies such as smart homes, Internet of Things, and artificial intelligence provides opportunities for the development of automated optimization solutions, which can utilize data acquired from the boiler and various sensors in real-time, implement consumption forecasting methodologies, and accordingly provide control instructions in order... [more]

A hall of residence with low energy performance was subjected to an extensive retrofitting program due to its high energy consumption, to enhance the building’s energy efficiency and reduce its energy costs and greenhouse gas emissions. The retrofitting program included the integration of a solar photovoltaic (PV) system installed on the building’s flat roof, among other factors. Nevertheless, the electricity supply provided by the system during the daytime proved insufficient to cover the building’s energy demand. Based on this, a study was implemented to analyze the contribution of the electricity produced by the solar PV system throughout the year to reduce power consumption under distinct solar radiation conditions, and to define a strategy to optimize renewable energy use by drawing up a set of organizational measures to be implemented to manage the PV solar system energy strategically. The strategic measures are mainly related to selecting the residence tasks with higher energy c... [more]

The operation of industrial supply technology is a broad field for optimization. Industrial cooling plants are often (a) composed of several components, (b) linked using network technology, (c) physically interconnected, and (d) complex regarding the effect of set-points and operating points in every entity. This leads to the possibility of overall optimization. An example containing a cooling tower, water circulations, and chillers entails a non-linear optimization problem with five dimensions. The decomposition of such a system allows the modeling of separate subsystems which can be structured according to the physical topology. An established method for energy performance indicators (EnPI) helps to formulate an optimization problem in a coherent way. The novel optimization algorithm OptTopo strives for efficient set-points by traversing a graph representation of the overall system. The advantages are (a) the ability to combine models of several types (e.g., neural networks and polyn... [more]

The ground source heat pump heating system is considered as one of the best solutions for the transition towards green heating under the continental climate conditions like Kazakhstan. In this paper, experimental and theoretical investigations were carried out to develop a ground source heat pump-based heating system under the weather conditions in Kazakhstan and to evaluate its thermodynamic performance. The water-to-water heat pump heating system, integrated with a ground source heat exchanger and used refrigerant R134a, was designed to provide hot water to meet the requirements for space heating. The predicted values of the coefficient of performance and the experimental results were found to be in good agreement within 6.2%. The thermodynamic performance of the system was also assessed using various environment-friendly refrigerants, such as R152a, R450A, R513A, R1234yf and R1234ze, as potential replacements for R134a. Although R152a is found to be a good alternative for R134a in t... [more]

The Internet of things (IoT) paradigm promotes the emergence of solutions to enable energy-management strategies. However, these solutions may favor the disposal or replacement of outdated but still necessary systems. Thus, a proposal that advocates the retrofit of pre-existing systems would be an alternative to implement energy monitoring. In this sense, this work presents a strategy for monitoring electrical parameters in real time by using IoT solutions, cloud-resident applications, and retrofitting of legacy building electrical systems. In this implementation, we adapted the SmartLVGrid metamodel to systematize the insertion of remote monitoring resources in low-voltage circuits. For this, we developed embedded platforms for monitoring the circuits of a building electrical panel and application for visualization and data storage in the cloud. With this, remote monitoring of the consumer unit was carried out in relation to energy demand, power factor, and events of variations of ele... [more]

Load survey has become a routine project for shipbuilding and shipping companies to investigate electrical load characteristics to enhance the power system planning and operation of marine vessels. In this brief perspective, we will outline a few steps to feeder losses analysis based on the result conducted by the load survey. The power flow and feeder loss analysis are extracted and used to determine the critical parameters that can significantly affect the system feeder losses used in the electrical load analysis in new ships. Exploring this new research direction will provide a more thorough understanding of feeder losses in marine vessel power systems. In this paper, a case study of container ship power loss analysis using the Newton−Raphson method is presented. The analysis results can provide shipbuilding corporations and ship owners with useful information for planning, designing, operating, and controlling shipboard power systems. As an energy-saving measure for ship microgrids... [more]

Services surrounding green buildings are specialised and directed towards the process of design and comprise comprehensive and quantified management in its entirety. Implicitly, consultancies are unable to deliver this service at the standard and pace required in the preliminary stages of design, and not all clients or consultants will require the services to be essential. The main aim is to stabilise the several characteristics prompting one another to optimise design performance against the optimisation algorithms. Green Star is a universal evaluation tool, assessing not only green characteristics but also elements that influence wellbeing and occupant health, such as indoor environment quality. The tools for Green Star rating can be used to measure the green features of a building from the design phase right to the stage of site handover (known as “As-Built”). This paper refers, in the literature review, to the passive and low-energy design methods of a Green Star-rated building at... [more]

A contemporary challenge for the construction industry is to develop a technology based on natural building materials which at the same time provides high energy efficiency. This paper presents the results of an airtightness test and a thermal imaging study of a detached house built with technology using cross laminated dowelled timber panels. The thermal conductivity coefficients of the wood wool used to insulate the walls and ceiling of the building have also been measured, the linear heat transfer coefficients of the structural nodes have been numerically determined, and calculations have been made regarding the energy efficiency of the building. On the basis of the research, it was found that the air exchange rate in the analyzed building n50 is at the level of 4.77 h−1. Air leaks were also observed in the places of connection of longitudinal walls with the roof and at the junction of window frames with external walls. The experimentally determined thermal conductivity coefficient... [more]

The scarcity of energy and water resources and rising temperatures due to climate change has set the focus on improving the energy efficiency of power plant thermodynamic cycles to adapt to higher heat sink temperatures and use fewer resources for energy production. In this work, a review of power production thermodynamic cycles is presented: from Brayton to Rankine and combined cycles, alongside particular cycles such as Organic Rankine Cycles, Kalina, Goswami or the more recently developed Hygroscopic Cycle. The efficiency of these cycles and their possible improvements are considered, as well as their environmental impact. Costs associated with existing power plants found in the literature have also been included in the study. The main existing facilities for each cycle type are assessed, and the most sustainable options in terms of resource consumption (fuel, water, etc.) and future perspectives to ensure both their energy efficiency and sustainability are identified.

This article deals with implementing a rule-based control method and startup sequence of a hybrid electric vehicle powered by a modular fuel cell system as its primary energy source and a lithium-ion battery system as its secondary energy source. The modular fuel cell system is composed of two separate fuel cell systems, electrically coupled to a one-power converter, using a programmable device. Depending on the vehicle’s operating mode, either both systems are used or just one of them. The vehicle’s fuel efficiency is improved by operating at constant power in the peak efficiency range of each fuel cell system. The experimental results show that the proposed system can significantly improve the fuel economy of a fuel cell vehicle and extend the driving range, while avoiding start/stop cycles. Additionally, this solution can increase the fuel cells’ lifecycle.

Building construction in rural Kyrgyzstan is heavily dominated by earthen buildings. Old and inappropriate residential building structures contribute significantly to high domestic space heating energy consumption. Therefore, it is necessary to understand the relevant building construction techniques. However, the scant information on Kyrgyz building techniques, especially for high-altitude rural settlements, was the prime motivation to perform the presented study. The key objective of the study is to investigate residential building construction techniques in high-altitude rural Kyrgyzstan, and this was to be achieved by house visits during field trips, literature review, and pilot interviews with local people. The analysis enabled the detailed identification of individual building envelopes as well as predominant building materials to be recorded. Based on the assessment, a housing profile was created that represents the typical characteristics of traditional rural Kyrgyz houses. Fur... [more]

The article aims to identify the relationship between energy efficiency and particular indicators of energy losses in Europe. The results of the bibliographic analysis showed a knowledge gap in energy losses in Europe regarding the new challenges of energy security. For the analysis, annual panel data from 32 European countries were collected from 1990 to 2019. The authors used the Jarque−Bera test to assess the normality of the residuals, utilized the Breush−Pagan test for heteroskedasticity check, and applied regression analysis to determine the relationship between energy efficiency and energy loss rates in Europe. To assess the effects of energy losses, the authors performed OLS modeling using the stats model’s package in Python. According to the modeling results, an increase in distribution losses (% of available energy from all sources) by 1% in Europe leads to an increase in energy consumption by 17.16% under other constant conditions. There is significant heterogeneity between... [more]

Depending on the temperature difference between the hot and cold sides of the thermoelectric generator (TEG), the output performance of the TEG can be produced. This means that it is necessary to force a TEG based on robust maximum power point tracking (MPPT) to operate close to its MPP at any given temperature or load. In this paper, an improved fractional MPPT (IFMPPT) is proposed in order to increase the amount of energy that can be harvested from TEGs. According to the suggested method, fractional order control is used. A moth-flame optimizer (MFO) was used to determine IFMPPT’s optimal parameters. A comparison of the results obtained by the MFO is made with those obtained by a particle swarm optimizer, genetic algorithm, gray wolf optimizer, seagull optimization algorithm, and tunicate swarm algorithm in order to demonstrate MFO’s superiority. IFMPPT’s primary objective is to enhance dynamic responses and exclude steady-state oscillations. Consequently, incremental resistance and... [more]

In order to objectively reflect the energy utilization performance of an active water heating system (AWHS) using photovoltaic/thermal (PV/T) modules, this study proposes a new evaluation method based on energy efficiency, exergy efficiency and thermal-electrical output of a system in year-round weather conditions. Four samples of PV/T modules were surveyed to compare and evaluate the effectiveness of the system, called MD1, MD2, MD3 and MD4, respectively. The simulation program was developed to suit four types of PV/T modules and MATLAB was used as the programming language. The water flow through the four PV/T module samples and the hot water tank volume were investigated for the highest exergy efficiency of the system. The final results illustrate that in the weather conditions of Ho Chi Minh City, Vietnam, the system has the highest energy efficiency, exergy efficiency and thermal output when using MD1 with 57.85%, 15.67% and 2.93 kWh/m2/day, respectively, while the system has highe... [more]

Decreasing production and rising prices of cars, especially those with electric drive, lead to longer use of cars with internal combustion engines. It can be assumed that in the future, more and more cars powered by such engines with high mileage and therefore high wear will be used. Engine wear leads to reduced efficiency and increased emissions. This paper analyzes the impact of wear of the piston−rings−cylinder system components on energy losses associated with gas leakage from the combustion chamber and friction of the rings against the cylinder liner in a car spark-ignition engine. A ring pack model was used for the analyses. The input data for the simulation were gained in measurements made on the engine test stand and measurements of the wear of the engine components used in the car. The energy losses associated with blow-by in an unworn engine ranged from 1.5% of the indicated work at high load to almost 5% at low load. In the engine after 300,000 km, these losses increased to... [more]

The article considers the main tendencies of development of alternative liquid fuels used in aviation, land transport, and for the needs of power generation sector. An overview of the main constraints to the development of alternative fuel technologies in these technical areas was carried out. The main groups of the most promising components and fuel compositions capable of effectively replacing conventional liquid fuels have been generalized. The basic criteria for evaluating alternative fuels are formulated. Environmental indicators of fuel combustion are of paramount importance for aviation. Rheological characteristics, calorific value, and environmental friendliness are critical for land transport engines. The effectiveness of alternative fuels for the power generation sector needs to be assessed in terms of such factors as economic, environmental, rheological, and energy to find an optimal balanced formulation. The list of potential components of alternative liquid fuels is extrem... [more]

Delivering water to consumers uses a lot of electricity. In the era of limited fossil fuel resources, we are increasingly looking at the possibilities of using renewable energy sources to power residential buildings or industries. The research aimed to analyze the potential of producing electricity from photovoltaic panels, ensuring electricity supplies for pumping water, and reducing costs. The tests were carried out using the existing photovoltaic (PV) installation with a capacity of 12.3 kW connected to the installation monitoring the production of electricity and monitoring the water-pumping station (WPS). An analysis of the daily electricity production from the PV installation, an analysis of the settlement unit’s demand for water, and an analysis of the costs of pumping water, including the unit cost of pumping 1 m3 of water, were carried out. Studies have shown the possibility of reducing water-pumping costs by more than 77.8% after a PV installation. The tested installation pro... [more]

The purpose of this article is to present a methodical approach to increasing the efficiency of a tug with an azimuth stern drive (ASD). The difficulties in the bow-to-bow (as a reverse tractor) operations of an azimuth stern-drive tug, while pulling at the assisted (towed) ship’s bow, are investigated through a parametric study. The authors’ original generic analytical model of a tug in a steady state is utilised. Various design and operation options are also compared, which cover the escort speed, hawser angle, and relative location of the towing point, among others. The latter also means a shift to stern-to-bow operation. The thruster power required and the remaining surplus for executing new alignment (steering) orders are assessed. The study is, thus, aimed at energy savings for the whole operation and, consequently, at long-term harbour-tug-fleet energy effectiveness. The basic output of the present research is the comparison of the behavioural and control patterns of various tug... [more]

Building energy efficiency is vital, due to the substantial amount of energy consumed in buildings and the associated adverse effects. A high-accuracy energy prediction model is considered as one of the most effective ways to understand building energy efficiency. In several studies, various machine learning models have been proposed for the prediction of building energy efficiency. However, the existing models are based on classical machine learning approaches and small datasets. Using a small dataset and inefficient models may lead to poor generalization. In addition, it is not common to see studies examining the suitability of machine learning methods for forecasting the energy consumption of buildings during the early design phase so that more energy-efficient buildings can be constructed. Hence, for these purposes, we propose a multilayer extreme learning machine (MLELM) for the prediction of annual building energy consumption. Our MLELM fuses stacks of autoencoders (AEs) with an... [more]

Following the international trend of using hydrogen as combustible in many industry branches, this paper investigates the impact of mixing methane gas with 23% hydrogen (G222) on condensing boilers’ operation. After modeling and testing several boilers with heat exchange surface different designs, the authors gathered enough information to introduce a new concept, namely High-Performance Condensing Boiler (HPCB). All the boilers that fit into this approach have the same operational parameters at nominal heat load, including the CO2 concentrations in flue gases. After testing a flattened pipes condensing boiler, a CO2 emission reduction coefficient of 1.1 was determined when converting from methane gas to G222 as combustible. Thus, by inserting into the national grid a G222 mixture, an important reduction in greenhouse gases can be achieved. For a 28 kW condensing boiler, the annual reduction in CO2 emissions averages 1.26 tons, value which was experimentally obtained and is consistent... [more]

The partial recovery of kinetic energy during braking allows the vehicle’s battery to be additionally charged and thus extends the range of an electric vehicle. Because of the different operating strategies of the braking energy recovery system, it is important to understand the factors influencing the level of recovered energy. The driving conditions at the place of use have a direct impact on the energy efficiency of an electric vehicle. The purpose of this paper was to analyze the energy recovered during braking in different driving conditions. The tests were based on the parameters of actual trips made along urban and suburban routes, and express roads. The collected actual speed profiles were used for the simulation studies. AVL cruise vehicle simulation software was used in the study. Simulation tests revealed that the levels of energy recovered during braking in an electric vehicle were the highest in urban conditions. The amount of energy recovered during urban driving can acco... [more]

The subject of the model research contained in this paper is an application of a motion energy−harvesting device on a crane-hoisting mechanism to power independent measurement devices. Numerical experiments focused on the selected motion energy−harvesting device (M-EHS) and its configuration properties in the context of energy-harvesting efficiency in the case of using it on a crane. The results of the computer simulations were limited to the initial specified conditions for the harvester and the movement of the conditions of the crane-hoisting mechanism. The article compares the energy efficiency for the selected construction and parameters of the harvester for specific hoisting speed and the arm length of the motion conversion system. For this purpose, the initial conditions for the crane and the configuration of parameters of the energy harvester were assumed. The results are visualized on the diagram of RMS voltage induced on piezoelectric elements, showing the impact of individual... [more]

Space missions will require the capability to build structures on site using local resources. Before 2040, NASA and the European Space Agency want to ensure the possibility of a permanent human residence in shelters on the Moon or Mars. The article analyzed the state of the art in this area based on the literature research. It shows innovative and energy efficient solutions for manufacturing the lunar and Martian shelters based on geopolymer composites. Firstly, the possible materials solutions, with particular attention to the geopolymer composites, are discussed. Next, the previous research is presented, including work based on different kinds of simulants of lunar and Martian regolith. Then, a different approach for manufacturing technologies is presented and the advantages of 3D printing technology are clarified. Eventually, the challenges for further projects are discussed, including energy and cost efficiency problems.

Low-carbon building regulations are acknowledged as critical instruments to facilitate the building industry’s decarbonization transition. However, recent studies have shown that non-compliance with low-carbon requirements is under-researched, leading to a significant divergence between policy intentions and actual performance. In light of this, the paper aims to provide a synthesis of existing research on non-compliance with low-carbon building regulations. It does this using a systematic literature review combined with bibliometric and text mining techniques. Through reviewing 26 scholarly works from the last decade, the paper demonstrates a peak production year around 2015, the year of the Paris Agreement, with the USA and Australia as key countries of concern. Subsequently, the study reveals three focused research areas: the development of building policy during the low-carbon transition; the role of building energy performance requirements in achieving low-carbon buildings; and bu... [more]