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This paper reviews the literature on maintenance strategies for energy efficiency as a potential maintenance approach. The purpose of this paper is to identify the main concept and common principle for each maintenance strategy for energy efficiency.

A literature review has been carried out on maintenance and energy efficiency. The paper systematically classified the literature into three maintenance strategies (e.g. inspection-based maintenance [IBM], time-based maintenance [TBM] and condition-based maintenance [CBM]). The concept and principle of each maintenance strategy are identified, compared and discussed.

Each maintenance strategy's main concept and principle are identified based on the following criteria: data required and collection, data analysis/modeling and decision-making. IBM relies on human senses and common senses to detect energy faults. Any detected energy losses are quantified to energy cost. A payback period analysis is commonly used to justify corrective actions. On the other hand, CBM monitors relevant parameters that indicate energy performance indicators (EnPIs). Data analysis or deterioration modeling is needed to identify energy degradation. For the diagnostics approach, the energy degradation is compared with the threshold to justify corrective maintenance. The prognostics approach estimates when energy degradation reaches its threshold; therefore, proper maintenance tasks can be planned. On the other hand, TBM uses historical data from energy monitoring. Data analysis or deterioration modeling is required to identify degradation. Further analysis is performed to find the optimal time to perform a maintenance task. The comparison between housekeeping, IBM and CBM is also discussed and presented.

The literature on the classification of maintenance strategies for energy efficiency has been limited. On the other hand, the ISO 50001 energy management systems standard shows the importance of maintenance for energy efficiency (MFEE). Therefore, to bridge the gap between research and industry, the proposed concept and principle of maintenance strategies will be helpful for practitioners to apply maintenance strategies as energy conservation measures in implementing ISO 50001 standard.

The novelty of this paper is in-depth discussion on the concept and principle of each maintenance strategy (e.g. housekeeping or IBM, TBM and CBM) for energy efficiency. The relevant literature for each maintenance strategy was also summarized. In addition, basic rules for maintenance strategy selection are also proposed.

In recent years, fast urban expansion in China has stimulated rapid energy consumption growth and increased environmental pollution. Therefore, it is important to utilize clean and renewable energy in district heating for the sustainable urban development. This study aimed to investigate the environmental and economic impacts of one hot dry rock (HDR) geothermal energy-based heating system in a life cycle framework.

By using the input–output-based life cycle analysis model, the energy consumption, CO₂ emission and other pollutants of the HDR-based heating system were evaluated and then compared with those of other four heating systems based on burning coal or natural gas. The life cycle costs of the HDR-based heating system were also analyzed.

The results showed that using HDR geothermal energy for heating can significantly reduce fossil fuel consumption, CO₂ emission as well as environmental pollution, and its life cycle costs are also competitive.

This study not only evaluated the environmental and economic impacts of the HDR-based heating system in a life cycle framework but also provided a methodological life cycle assessment framework that can estimate both economic and environmental benefits, which can be used in policy making for China’s urban development.

This paper aims to present the details of a study undertaken to develop an energy-based time equivalent approach to obtain the fire resistance ratings (FRRs) of light gauge steel frame (LSF) walls exposed to realistic design fire curves.

The energy-based time equivalent method was developed based on the performance of a structural member exposed to a realistic design fire curve in comparison to that of the standard fire time – temperature curve. The FRR predicted by the energy-based method for LSF wall configurations exposed to both rapid and prolonged fires were compared with those from fire design rules and finite element analyses (FEA).

The proposed energy method can be used to obtain the FRR of LSF walls in case of prolonged fires and cannot be used for rapid fires as the computed FRRs were higher than the results from FEA and fire design rules due to the influence of thermal bowing and its magnification effects at a high temperature gradient across the studs for rapid fires.

The energy-based time equivalent method was developed based on equal fire severity principles. Three different wall configurations were considered and exposed to both rapid and prolonged fires. The FRR obtained from the energy-based method were compared with fire design rules and FEA results to assess the use of the energy-based method to predict the FRR of LSF walls.

This case describes the growth of ReNew Power during its first decade of operation. Sumant Sinha, a first-generation entrepreneur and former banker, founded the company, which grew from a modest generator-cum-developer of wind energy-based electricity to one of India's largest companies in the renewable energy sector. With the entry of large, well-funded players such as Tata Power and Adani Green into the Indian renewable sector by the end of 2020, Sinha had to make a strategic decision: should ReNew continue to organically scale up its presence in an increasingly competitive yet expanding Indian renewable energy sector, should it diversify geographically, or should it pursue emerging opportunities for vertical or horizontal integration within the sector? The case provides an opportunity to discuss how alternative business models and competitive scenarios may facilitate or inhibit the growth of a player in the renewable energy sector.

The aim of this paper is to present the rationale, a numerical example and a case study of the application of an algorithm to convert non‐calendar based preventive maintenance (PM) schedules into calendar‐time format for semiconductor manufacturing systems (SMS). The resulting calendar‐time PM schedules can be utilized as a baseline within a PM scheduling optimization process.

The algorithm utilizes estimations of work‐in‐process (WIP) and system parameters to estimate an equivalent calendar‐time schedule for PM schedules based on different units. A numerical example based on fictitious data illustrates the utilization of the conversion algorithm within a mixed PM scheduling scenario, including wafer, processing‐time and energy‐based PM tasks for multi‐chamber tools. In addition, a case study illustrates the accuracy of the algorithm by comparing estimated PM targets (i.e. due, warning and late dates) with historical data from a real semiconductor fabrication facility.

Results from the case study validated the conversion algorithm by showing accurate estimations of PM targets (i.e. due, warning and late dates). The accuracy of the algorithm depends, however, on good estimates for WIP levels within the planning horizon.

The conversion algorithm may be utilized not only in SMS but also in other industries that require the conversion of non‐calendar based PM schedules into calendar‐time format for PM optimization and operational purposes.

The purpose of this paper is to assess renewable energy‐based cooling technologies using multi‐criteria methodology.

Analytic hierarchy process (AHP) methodology is applied to obtain the ranking of renewable energy options for cooling technology using five different criteria. In total, seven technologies were analyzed, based on the opinions obtained from experts and the extensive literature survey made and the ranking was obtained using AHP method.

The present findings revealed that the ranking for the renewable energy‐based cooling technologies were in the following order: biomass combustion, biogas, trigeneration, SPV, biomass gasifier, solar thermal storage, and hybrid technology. Only 5 per cent variation in global priority exists among top three options. This variation is considered insignificant due to rapidly varying factors such as technological advancements, government promotional schemes, fuel availability, etc. and hence these three options may be ranked equally.

The research output is helpful in identifying the technology, with promising potential for promoting technology on a wider scale. Additional attributes and sensitivity analysis can be included for further research.

The paper usefully describes the AHP methodology utilized in the present study and the ranking made for the evaluation of renewable energy‐based cooling systems. The outcome of the present study would benefit policymakers, researchers and entrepreneurs when choosing the appropriate cooling technology.

Electric motor heating during biomass recovery and its handling on conveyor is a serious concern for the motor performance. Thus, the purpose of this paper is to design and develop a hardware prototype of master–slave electric motors based biomass conveyor system to use the motors under normal operating conditions without overheating.

The hardware prototype of the system used master–slave electric motors for embedded controller operated robotic arm to automatically replace conveyor motors by one another. A mixed signal based embedded controller (C8051F226DK), fully compliant with IEEE 1149.1 specifications, was used to operate the entire system. A precise temperature measurement of motor with the help of negative temperature coefficient sensor was possible due to the utilization of industry standard temperature controller (N76E003AT20). Also, a pulse width modulation based speed control was achieved for master–slave motors of biomass conveyor.

As compared to conventional energy based mains supply, the system is self-sufficient to extract more energy from solar supply with an energy increase of 11.38%. With respect to conventional energy based \ of 47.31%, solar energy based higher energy saving of 52.69% was reported. Also, the work achieved higher temperature reduction of 34.26% of the motor as compared to previous cooling options.

The proposed technique is free from air, liquid and phase-changing material based cooling materials. As a consequence, the work prevents the wastage of these materials and does not cause the risk of health hazards. Also, the motors are used with their original dimensions without facing any leakage problems.

This study aims to examine the farmers’ awareness level and explores the factors, which may influence their adoption intention regarding solar powered pumps.

The study consist of a sample of 510 respondents selected from the rural region of Punjab (India) by using convenience sampling. Descriptive analysis, exploratory factor analysis, confirmatory factor analysis and multiple regression analysis techniques have been used for the analytical purpose.

The study reveals that dimensions such as perceived benefit, perceived compatibility and government incentives have a significant impact on intention to use solar powered pumps, whereas high investment cost and lack of awareness regarding government subsidies are the main reason for non-adoption of the same.

The sample size has been selected on the basis of convenience sampling and has been taken from the rural area, which may affect its generalizability.

The present research is expected to be useful for the manufacturers, regulators, customers, commercial banks, product and service providers, and other environmental institutions.

The study has acknowledged various intentional factors, which influence the adoption decision of solar powered pumps. Therefore, the present study will be useful to formulate action plans to improve the environmental quality.

The rapid rising of renewable energy sources particularly wind energy cannot be ignored. The numerical increase in wind energy farms throughout the world is the best example. The purpose of this paper is to assess the basic question of whether wind characteristics affect the performance and cost of energy. The importance of this question cannot be ruled out while comparing renewable energy to a conventional form of energy more specifically especially for the developing country where the cost of energy is very high.

The research design of this paper is consists of an assessment of local wind characteristics of the wind farm site using Weibull k and c parameters. The performance model is used to assess the performance of the wind turbine (WT) corresponding to local wind characteristics. The wind correlation with WT in terms of changing wind speed has been assessed to quantify the effects of wind speed on the WT behavior and failure of WT components. Similarly, the power curve of WT is assessed and compared with the International Electrotechnical Commission standards 61400-12-2. The WT power coefficient and tip speed ratio corresponding to wind speed is also investigated. The energy volume and cost of energy lost model is used to determine the cost and volume loss of energy/kWh of the wind farm.

The findings of practical wind farms showed that the wind conditions of the site are showing a strong tendency that can be determined from the results of Weibull k and c parameters. The k and c parameters are observed to be 3.44 and 9.16 m/s, respectively, for a period of a year. The standard deviation is observed to be 2.56 for a period of a year. WT shows the efficient behavior can be obtained from the power coefficient and tip speed of WT at different wind speeds. Also, wind farm observation showed that to be some increasing wind speed cause of based WT component failures. The results of energy volume and cost/kWh assessment showed that the major portion of energy volume and cost of energy is lost owing to network, voltage dip and frequency surge, electrical and mechanical components failures.

Generally, it can be concluded that the WTs are now able to cope with variable wind speeds. However, the results of this paper are showing that WT performance and availability decreased due to increased wind speeds. It can also be a reason to decreased volume and increase the cost of energy/kWh.

Recently, there has been a shift toward the embodied energy assessment of buildings. However, the impact of material service life on the life-cycle embodied energy has received little attention. We aimed to address this knowledge gap, particularly in the context of the UAE and investigated the embodied energy associated with the use of concrete and other materials commonly used in residential buildings in the hot desert climate of the UAE.

Using input–output based hybrid analysis, we quantified the life-cycle embodied energy of a villa in the UAE with over 50 years of building life using the average, minimum, and maximum material service life values. Mathematical calculations were performed using MS Excel, and a detailed bill of quantities with >170 building materials and components of the villa were used for investigation.

For the base case, the initial embodied energy was 57% (7390.5 GJ), whereas the recurrent embodied energy was 43% (5,690 GJ) of the life-cycle embodied energy based on average material service life values. The proportion of the recurrent embodied energy with minimum material service life values was increased to 68% of the life-cycle embodied energy, while it dropped to 15% with maximum material service life values.

The findings provide new data to guide building construction in the UAE and show that recurrent embodied energy contributes significantly to life-cycle energy demand. Further, the study of material service life variations provides deeper insights into future building material specifications and management considerations for building maintenance.