A New Approach to Mixed/Boundary Friction Prediction Using the Logistics Curve

There is a strong focus on improving the energy efficiency of machines. Over the last 20-30 years, one way to improve energy efficiency has been to reduce lubricant viscosity. This also has the effect of leading to thinner oil films between the machine’s moving surfaces and is likely to lead to increased mixed/boundary friction. Accurately predicting friction in the mixed/boundary friction regime is therefore becoming of great importance. The work reported here suggests that commonly used asperity friction models significantly underestimate friction in the mixed/boundary friction, and a new model, based on a logistic curve fit, gives a better estimate of mixed/boundary friction, provides good agreement with experimental friction data (from Mini Traction Machine experiments), and is much more straightforward for engineers and tribologists to apply for the estimation of mixed/boundary friction losses.

Assessment of Indoor Air Quality in Residential Buildings of New England through Actual Data

Several studies on indoor air quality (IAQ) and sick building syndromes have been completed over the last decade, especially in cold countries. Efforts to make homes airtight to improve energy efficiency have created buildings with low ventilation rates, resulting in the build-up of indoor pollutants to harmful levels that would be otherwise unacceptable outdoors. This paper analyzed the infiltration rates, indoor temperatures, and variations in CO2, 2.5 μm particulate matter (PM2.5), and total volatile organic compound (TVOC) concentrations over the fall of 2021 in several homes in New England, USA. A relationship between outdoor and indoor conditions and ventilation strategies has been set using the results from blower door tests and actual indoor air quality data. Although all case studies lacked mechanical ventilation devices, such as those required by ASHRAE Standard 62.2, natural ventilation and air leakage have been enough to keep VOCs and PM2.5 concentration levels at acceptable values most of the studied time. However, results revealed that 25% of a specific timeframe, the occupants have been exposed to concentration levels of CO2 above 1000 parts per million (ppm), which are considered potentially hazardous conditions.

НАУКОВА ПРОЄКТНА ДІЯЛЬНІСТЬ ЯК ПЕРЕДУМОВА ФОРМУВАННЯ ФАХОВИХ КОМПЕТЕНТНОСТЕЙ ЗДОБУВАЧІВ ВИЩОЇ ОСВІТИ З ЕЛЕКТРИЧНОЇ ІНЖЕНЕРІЇ

Purpose. Determination of the role of scientific project activity in the formation of professional competencies of applicants for higher education in the field of electrical engineering.Methodology. The method of scientific projects is used to form the professional competencies of applicants for higher education in the specialty “Electricity, electrical engineering and electromechanics”.Findings. The implementation of project scientific activities using the base of engineering and scientific projects to improve energy efficiency motivates applicants for higher education to acquire new knowledge, creates the preconditions for the development and implementation of a modern educational program in the field of electrical engineering, contributes to the integration of a new structure into the university system – an energy-innovative hub of knowledge.Originality. In the work design methods and teaching technologies in the field of electrical engineering were further developed, which provide the use of the university base of scientific and engineering projects on energy efficiency and participation in the implementation of projects of applicants for higher education, which allows to form professional (scientific-research) competencies of applicants and to develop modern educational program.Practical value. The research results can be used to update educational programs in electrical engineering and to support the development of energy efficiency at the university when creating an energy-innovative knowledge hub that will allow organizing a complex interaction of the components “education – science (innovation) – business (entrepreneurship) – state”.

Path Tracking of an Underwater Snake Robot and Locomotion Efficiency Optimization Based on Improved Pigeon-Inspired Algorithm

This paper considers the tracking control of curved paths for an underwater snake robot, and investigates the methods used to improve energy efficiency. Combined with the path-planning method based on PCSI (parametric cubic-spline interpolation), an improved LOS (light of sight) method is proposed to design the controller and guide the robot to move along the desired path. The evaluation of the energy efficiency of robot locomotion is discussed. In particular, a pigeon-inspired optimization algorithm improved by quantum rules (QPIO) is proposed for dynamically selecting the gait parameters that maximize energy efficiency. Simulation results show that the proposed controller enables the robot to accurately follow the curved path and that the QPIO algorithm is effective in improving robot energy efficiency.

Optimized Base Station Sleeping and Smart Grid Energy Procurement Scheme to Improve Energy Efficiency

In this chapter, the authors propose a joint BS sleeping strategy, resource allocation, and energy procurement scheme to maximize the profit of the network operators and minimize the carbon emission. Then, a joint optimization problem is formulated, which is a mixed-integer programming problem. To solve it, they adopt the bi-velocity discrete particle swarm optimization (BVDPSO) algorithm to optimize the BS sleeping strategy. When the BS sleeping strategy is fixed, the authors propose an optimal algorithm based on Lagrange dual domain method to optimize the power allocation, subcarrier assignment, and energy procurement. Numerical results illustrate the effectiveness of the proposed scheme and algorithm.

An IoT measurement solution for continuous indoor environmental quality monitoring for buildings renovation

The measurement of Indoor Environmental Quality (IEQ) requires the acquisition of multiple quantities regarding thermal comfort and indoor air quality. The IEQ monitoring is essential to investigate the building’s performance, especially when renovation is needed to improve energy efficiency and occupants’ well-being. Thus, IEQ data should be acquired for long periods inside occupied buildings, but traditional measurement solutions could not be adequate. This paper presents the development and application of a non-intrusive and scalable IoT sensing solution for continuous IEQ measurement in occupied buildings during the renovation process. The solution is composed of an IR scanner for mean radiant temperature measurement and a desk node with environmental sensors (air temperature, relative humidity, CO2, PMs). The integration with a BIM-based renovation approach was developed to automatically retrieve building’s data required for sensor configuration and KPIs calculation. The system was installed in a nursery located in Poland to support the renovation process. IEQ performance measured before the intervention revealed issues related to radiant temperature and air quality. Using measured data, interventions were realized to improve the envelope insulation and the occupant’s behaviour. Results from post-renovation measurements showed the IEQ improvement achieved, demonstrating the impact of the sensing solution.

Determining the awareness and knowledge of officers towards ship energy efficiency measures

Improving energy efficiency practices on ships is crucial for both economic and environmental purposes. Both technical and operational applications are made to increase energy efficiency on ships. The success of energy efficiency applications on ships depends on the effective work of seafarers. Therefore, awareness and knowledge about the energy efficiency of seafarers should be enough. The aim of the study is to determine the awareness and knowledge level of seafarers on energy efficiency on ships and to evaluate energy efficiency practices in maritime transportation companies from the perception of seafarers. In the study, the survey method was used. As a result of the survey, it was found that the knowledge level of the seafarers on ship energy efficiency was low, almost half of them did not receive energy efficiency training but they were informed about the importance of the issue. At the end of the study, it was evaluated that the awareness and knowledge level of officers should be increased in order to improve energy efficiency on ships and suggestions on this issue were determined.

Energy Recovering Using Regenerative Braking in Diesel–Electric Passenger Trains: Economical and Technical Analysis of Fuel Savings and GHG Emission Reductions

Rail transport, specifically diesel–electric trains, faces fundamental challenges in reducing fuel consumption to improve financial performance and reduce GHG emissions. One solution to improve energy efficiency is the electric brake regenerative technique. This technique was first applied on electric trains several years ago, but it is still considered to improve diesel–electric trains efficiency. Numerous parameters influence the detailed estimation of brake regenerative technique performance, which makes this process particularly difficult. This paper proposes a simplified energetic approach for a diesel–electric train with different storage systems to assess these performances. The feasibility and profitability of using a brake regenerative system depend on the quantity of energy that can be recuperated and stored during the train’s full and partial stop. Based on a simplified energetic calculation and cost estimation, we present a comprehensive and realistic calculation to evaluate ROI, net annual revenues, and GHG emission reduction. The feasibility of the solution is studied for different train journeys, and the most significant parameters affecting the impact of using this technique are identified. In addition, we study the influence of electric storage devices and low temperatures. The proposed method is validated using experimental results available in the literature showing that this technique resulted in annual energy savings of 3400 MWh for 34 trains, worth USD 425,000 in fuel savings.

The Effect of Urban Spatial Form on Energy Efficiency: A Cross-Sectional Study in China

Rational planning and optimization of urban spatial form to achieve the goal of energy efficient utilization and carbon emission reduction is one of the important ways to improve energy efficiency. We deconstruct urban spatial form into centrality, aggregation and complexity, and analyze net effect and its heterogeneity of urban spatial form on energy efficiency with OLS, quantile regression model as well as grouped regression model. The results show that the effects of urban spatial centrality and complexity on energy efficiency are nonlinear. For the vast majority of cities, strengthening urban spatial centrality will significantly improve energy efficiency, but the growth rate will gradually decrease. The impact effect of urban complexity on energy efficiency has the characteristics of U-shaped trend with an inflection point value of 0.429. And for the three-quarters of urban samples, enhancing urban spatial complexity will reduce energy efficiency. The positive effect of urban spatial aggregation on energy efficiency is only significant in cities with high quantile for energy efficiency. In terms of urban heterogeneity, the positive effects of spatial centrality and aggregation on energy efficiency are more obvious in megacities with a permanent population of more than 5 million, and the negative effect of spatial complexity on energy efficiency is more obvious in small and medium-sized cities. Whether it is promotion or inhibition, the urban samples with high energy efficiency are more affected by the change of urban spatial form. Optimizing the urban spatial form is one of the important ways to improve the energy efficiency, and the policy setting should give full consideration to the urban heterogeneity and classified policies.

PECULIARITIES OF DETERMINATION OF ECONOMIC INDICATORS OF EXECUTIBILITY OF IMPLEMENTATION OF MEASURES TO INCREASE ENERGY EFFICIENCY

The work is devoted to the analysis of the peculiarities of determining the economic indicators of the feasibility of implementing measures to improve energy efficiency. In contrast to energy saving, which aims to reduce the consumption of energy resources, energy efficiency is a matter of appropriate energy consumption. That is, the use of less energy for the same level of supply of buildings or industries. The topic is relevant, because now energy prices are rising every year. At the same time, the International Energy Agency estimates an increase in total resource needs by 25% by 2040. To achieve this goal, standard measures aimed at improving the energy efficiency of buildings, the effects of the implementation of these measures, a number of economic indicators, including PP, ARR, NPV, PI, BCR, SIR, MARR, IRR and DPP, were analyzed, evaluated and grouped. The focus was on the dynamic group of indicators due to the fact that their calculation involves the use of a discounting procedure. The general scheme of all dynamic indicators is the same and is based on forecasting costs and revenues for the planning period. The indicators of this group take into account changes in the value of money over time, which is neglected by the indicators of the static group. The most popular indicators are the calculation of net present value (NPV) and the definition of profitability index (PI). This work can be used to solve the problem of low energy efficiency and insufficient funding for the modernization of the building