Unused Energy Research Articles

Variable renewable energy penetration impact on productivity: A case study of poultry farming.

Like all current industrial systems, agriculture overwhelmingly relies on energy supply from controllable sources, mainly fossil fuels and grid electricity. Power supply from these sources can be adapted to perfectly match the timing of power requirements of demand systems. The energy transition largely consists in substituting renewable power-which is intermittent by nature-to controllable sources, leading to disconnection between instantaneous power production and demand. Energy storage is a potential solution for balancing production and demand and safeguarding the operating conditions of the demand system. In this paper we quantify the effects of renewable power supply (solar and wind) on the operation of a standard poultry farm. We model the balance of power generation and demand considering the growth conditions of poultry and local weather data including temperatures, wind speed and solar radiation. We assess scenarios of renewable power supply in function of the size of the power plant, the wind-to-solar power generation mix and energy storage, and assess the impact of power supply patterns on the operating intensity (productivity) of the demand system. We show that, with a limited storage capacity, it is possible to achieve non-negligible shares of renewable power penetration without major loss in farm productivity. However, a full transition to renewable power would require the combination of i)-large energy storage compared to the annual demand, ii)- significant oversizing of the power production plant, and iii)-the exclusion of power generation combinations (wind/solar) that deviate from the timing of demand. Storage and power plant oversizing is all the more critical as production and demand are uncorrelated over the year. The ratio of useful to unused energy storage by the end of the year varies with the energy mix and operating intensity (productivity) of the farm. We discuss the implications of different energy configurations on the performance of the demand system.

USE OF SECONDARY ENERGY RESOURCES TO PROVIDE HOT WATER SUPPLY TO BUILDINGS AND CONSTRUCTIONS

The paper assesses the possibility of using secondary energy resources to provide hot water supply to buildings and constructions. The introduction of recovery systems by using previously unused cheap waste heat energy helps to reduce the amount of energy produced and consumed, increase energy efficiency, and reduce greenhouse gas emissions, which correspond to the development strategy of the construction industry and housing and communal services in the field of environmental protection and energy saving. A method for using the waste heat energy of refrigeration plants to provide hot water supply to an apartment building is proposed. This method makes it possible to ensure uninterrupted supply of hot water to consumers with minimal dependence on the operation of centralized heat supply systems. The minimum power of waste thermal energy sources necessary for the organization of such systems is calculated, and possible sources of secondary energy resources are proposed.

Tapping the Unused Energy Potential of Solar Water Pumps in India.

India seeks to deploy millions of solar water pumps to farmers who often lack access to electricity or face an unreliable power supply. Improving the use of this technology can bolster sustainable agriculture and expand clean energy services. We investigate farm-level impacts and opportunities with primary survey data (n = 292 farmers) and a large real-time pump operational data set (n = 1106 pumps). By modeling the potential solar generation of off-grid solar water pumps, we estimate 300-400 kWh/month of unutilized solar energy per pumping system, representing up to 95% of potential generation. While farmers report increased revenues and ease of pump operation, unsolved challenges concerning the lack of panel cleaning and tracking remain. Pump operational data show pump usage in the summer and monsoon seasons and an expansion of irrigation to grow crops in the winter. Relative to emissions associated with the use of diesel pumps, solar pumps that are highly utilized reduced life cycle CO2-eq emissions by 93% on average, while the pumping systems with the lowest use result in a net increase of 26% relative to the diesel alternatives. Based on observed usage rates, approximately 70% of pumps had positive environmental benefits. The high share of unutilized solar energy provides a significant opportunity to use the energy for nonpumping purposes.

Unjuk Kerja Termal Kolektor Surya PV/T Bersirip Menggunakan Metode Computing Fluid Dynamic

Photovoltaic Thermal (PV/T) collector is a device that can produce electrical energy and thermal energy simultaneously. However, the thermal energy increases the surface temperature of the PV and therefore it may reduce electrical efficiency. To overcome this problem, a finned thermal collector should be joined underneath the PV surface. The aim of this study is to simulate the thermal performance of a PV/T collector by using staggered fins with air as a working fluid. The parameters are varied from 25 to 50 mm in the fin geometry and from 12 to 48 g/s in air mass flow rate, respectively. Furthermore, the heat radiation used was 860 W⁄m2 and Computing Fluid Dynamic (CFD) method was implemented in this research. The results showed that the PV/T surface temperature decreased by 7.04 % for the fin height of 37.5 mm and 11.9 % for the fin height of 50 mm when compared to the fin height of 25 mm. Thus, a greater cooling of the PV/T surface occurs in the fin height of 50 mm due to an increase in the heat transfer area which might absorb more of the unused thermal energy in comparison with others.

A Comprehensive Review on the Novel Principles, Development and Applications of Triboelectric Nanogenerators

AbstractThe major aim of this study is to provide a broad review of the fundamental ideas, progress, and utilization of triboelectric nanogenerators (TENGs). The modes and operations of numerous triboelectric nanogenerator configurations along with applications and materials are also discussed. Triboelectric nanogenerators, a ground-breaking power production technology, were unveiled in 2012 and classified as one of the most effective generators to convert unused mechanical energy into electrical energy to run a wide range of devices. Triboelectric nanogenerators have made significant progress since the creation of this novel power-generation technology. The operating principles of various modes, such as freestanding triboelectric-layer, single-electrode, lateral sliding, and vertical contact-separation have also been carefully investigated in order to give readers a deeper understanding of the technology. The key applications of TENGs, such as high voltage power supply, blue energy, self-power sensors, and micro/nano-energy, are also described in this work along with concepts for further research. As a result, triboelectric nanogenerators are very important and attractive technology with advantages of low cost, straightforward construction, simple fabrication, high efficiency, and relatively high output performance. Wide range of material choice allows researchers to use the technology in many configurations with multiple applications. Numerous scientific modeling and analysis are also reviewed for a more solid understanding of this revolutionary and unique technology.

Assessment of the Newcomen engine’s development potential as heat engine for low temperature waste heat

There is a large but mostly unused energy resource available from low temperature waste heat with temperatures of 80–150°C. The lack of a cost-effective technology prevents the generation of power from this potential. Recently, the Condensing Engine, which employs the condensation of steam and the arising vacuum as the driving force, had been developed to address this problem. Its simplicity and the use of water as working fluid promises cost-effectiveness. In the context of this work, it was decided to investigate the Newcomen Engine to assess its potential. This engine is usually neglected because of is low efficiency, thought to be caused by the continuous cooling and re-heating of the cylinder. A thermodynamic model of the engine was developed. Surprisingly, the model indicated that 78% of the heat losses are caused by the re-heating of the injection water and only 22% by the cooling and re-heating of the cylinder. This finding allowed to conceptualise a new engine, the Internal Condensation Engine, where plastic material for the cylinder and the forced ejection of the water minimise losses. The engine would have a similar or better efficiency than competitive technologies whilst being simpler, and therefore more cost-effective.

Energy flow analysis of grass carp pond system based on Ecopath model

Grass carp (Ctenopharyngodon idellus) is the most productive freshwater fish in China, but its traditional aquaculture model still has problems, such as poor water quality and frequent diseases. We have taken monoculture and 80:20 polyculture grass carp ponds as the research object and used EwE software to build the Ecopath model of two ponds. We analyzed and compared the characteristics of ecological structure and energy flow in two ponds. The result showed the highest effective trophic level in the polyculture pond that was higher than that in the monoculture pond, and fish in polyculture had higher EE values which showed the production of fish in polyculture contributed more to the energy conversion efficiency of the ecosystem. Flows into detritus were the largest component of TST both in the two ponds, which accounted for 49.34% and 50.37%. And the average transfer efficiency in monoculture was 13.07%, while that in polyculture was 15.6%. The ascendency/total development capacity (A/TDC) and overhead/total development capacity (O/TDC) were 0.35 and 0.65 both in the two ponds, respectively, which indicated that both systems had a strong anti-perturbation ability, but the stability could be improved. Finn’s cycling index (FCI) in polyculture was higher and showed that the polyculture pond was more mature and stable. Unused energy of functional groups will flow to detritus, and that in the monoculture pond was higher, the energy of C. idellus that flowed to detritus in monoculture was 48.17% higher than that in polyculture; unused energy of bacteria and phytoplankton were also high. The result showed that polyculture could improve energy utilization, increase transfer efficiency, and raise the stability of the ecosystem. Grass carp ponds still need to be improved in the aspects of mixed species and energy consumption. It is necessary to improve the ecological and economic benefits of grass carp ponds by optimizing the aquaculture structure and adjusting the aquaculture proportion.

Enhanced Mechanical Energy Harvesting in Triboelectric Nanogenerator by the Reinforcement of Polypyrrole‐Decorated rGO Sheets in PDMS

Energy harvesting triboelectric nanogenerators (TENGs) to scavenge unused mechanical energy have received significant attention in this decade. Herein, the development of reduced graphene oxide (rGO):polypyrrole (PPy) hybrid‐modified polydimethylsiloxane (PDMS) as TENG for various device applications is reported. The bulk of PDMS is altered by different fillers such as rGO, PPy, and the binary hybrids of rGO and PPy with varying weight ratios. Among various PDMS composites, 1 wt% of 1:8 rGO:PPy–PDMS composite exhibits higher TENG responses than other PDMS composite. The superior TENG performances of 1 wt% 1:8 rGO:PPy–PDMS composite are attributed to the formation of intensified negative charges inside the PDMS matrix. This charge intensification in the composite is due to various mechanisms, including the charge trapping ability of rGO:PPy filler, microcapacitor formation by introducing hybrid filler in the system with proper conducting networks, and the electron‐donating nature of PPy conducting polymer. A 3D stacked device proposed using 1 wt% 1:8 rGO:PPy–PDMS composite delivered a short‐circuit current of 16 μA and an open‐circuit potential of 60 V by simple palm pressing. Also, the ability of the stacked device for charging/powering portable devices and light‐emitting diodes is demonstrated.

Technical modelling of solar photovoltaic water pumping system and evaluation of system performance and their socio-economic impact

Water is a precious resource for agriculture and most of the land is irrigated by tube wells. Diesel engines and electricity-operated pumps are widely used to fulfill irrigation water requirements; such conventional systems are inefficient and costly. With rising concerns about global warming, it is important to choose renewable energy source. In this study, SPVWPS has been optimally designed considering the water requirement, solar resources, tilt angle and orientation, losses in both systems and performance ratio. A PVSyst and SoSiT simulation tools were used to perform simulation analysis of the designed solar photovoltaic WPS. After designing and performance analysis, farmers were interviewed during fieldwork to assess socioeconomic impacts. In the result section, performance of PV system is analyzed at various tilt angles and it is established that system installed at a 15° tilt angle is more efficient. The annual PV array virtual energy at MPP of designed photovoltaic system is 33342 kWh and the annual energy available to operate the WPS is 23502 kWh. Module array mismatch and ohmic wiring losses are 374.16 kWh and 298.83 kWh, respectively. The total annual water demand of the selected site is 80769 m³ and designed SPWPS pumped 75054 m³ of water, supplying 92.93% of the irrigation demand. The normalized values of the effective energy, system losses, collection losses and unused energy in the SPVWP system are 2.6 kW/kWp/day, 0.69 kW/kWp/day, 0.72 kW/kWp/day and 0.48 kW/kWp/day, respectively. The annual average performance ratio of the proposed system is 74.62%. The results of the interviews showed that 70% of farmers are extremely satisfied with the performance of SPVWPS and 84% of farmers indicated that they did not incur any operating costs. The unit cost of the SPWPS is 0.17 €/kWh, which is 56.41% and 19.04% less expensive than the cost of diesel and grid electricity.

A novel dynamic pricing model for a microgrid of prosumers with photovoltaic systems

Due to the growing demand for electricity and the increasing number of consumers who can produce energy (prosumers) using photovoltaic systems today, energy generated by prosumers can be utilized in the microgrid instead of selling it to the main utility grid. Pricing is one of the most important mechanisms for motivating prosumers to interact with each other in the microgrid. Many works have proposed different pricing models that mostly focus on optimizing prosumers’ behavior and energy usage costs. However, most of the proposed models require constant involvement of the end-user to adjust energy consumption profiles, which is not always possible in a real-world scenario. In this paper, a novel pricing model is presented with the aim of maximizing the utilization of energy generated in the microgrid and reducing the import of energy from the utility grid, whereas ensuring more beneficial prices for energy within the microgrid compared with the utility grid. Mathematical models based on the supply and demand ratio and prosumers’ absolute deviation from the predicted energy usage profiles are developed to determine the internal equilibrium price and the amount of energy each prosumer can buy and sell by interacting with the microgrid. To cover the energy transfer losses in the microgrid, a dynamic loss allocation mechanism is proposed. The proposed pricing model is validated using real energy usage profiles from 100 prosumers. The results show that the total energy usage cost can be decreased, whereas the amount of unused energy that is shared outside the microgrid is minimized.

Credibility-based cascading approach to achieve net-zero emissions in energy symbiosis networks using an Organic Rankine Cycle

Industrial symbiosis (IS) integrates multiple industries to share resources (e.g., energy, water, by-materials) for economic and environmental reasons. Energy demand is dynamic, imposing financial and logistical barriers to achieving Circular Energy (CEn). This paper addresses this by proposing a new framework that integrates central heating networks of an Organic Rankine Cycle (ORC) system to recover unused low-temperature energy. The framework is formulated as a stochastic programming problem to capture the uncertainty of some parameters to reduce the costs arising from fluctuations in energy supply and demand and, subsequently, wasted energy. Disruption management is also applied to handle the risk of suppliers becoming unavailable due to unforeseen events. The proposed multi-objective mixed-integer linear programming model optimizes the conflicting sustainability value preferences in the IS-based CEn network. The paper presents a novel robust possibilistic programming technique to control the epistemic uncertainty of the developed mode and develops a robust variant of the augmented ε-constraint algorithm (AUGMECON-R) to obtain the Pareto optimal solutions. The results provide a new platform for reducing the undesirable effects of worst-case energy symbiosis scenarios. The results show that using ORCs in an IS network increases the economic benefits of such a system by about 20% and reduces customer dissatisfaction from energy supply disruptions by about 27%.

Household Energy Conservation Practices Used in Chalimbana Ward, Chongwe District

Energy conservation is a subject that has continued to attract global attention as it essential in ensuring that the growing energy demand does not pose a threat to the environment. In view of this, the aim of this study was to find out the household energy conservation practices used in Chalimbana ward of Chongwe district, Zambia. The study adopted a convergent mixed method research design. Qualitative data from 10 purposively sampled key informants was collected through in-depth-interviews using semi-structured interview guides. Additionally, quantitative data from 175 households selected through cluster sampling technique was collected using a questionnaire. The qualitative data was analysed though content analysis whereas quantitative data was analysed through descriptive statistics and multiple linear regression. The study found that most households in Chalimbana ward depend on traditional biomass energy (Charcoal and firewood). Through multiple linear regression, the study found that expenditure on household energy consumption in the study area is influenced is influenced by social economic factors such as family size, house size and education. To conserve energy, the households in this area use a variety of conservation methods of which the most used involves switching or putting off unused household energy appliances or sources. The energy used among these households causes air pollution, habitat loss, land use change, exposure to hazardous waste among other environmental atrocities While the study findings show that households in Chalimbana ward do practice energy conservation, this is not done at a substantive level that can yield sustainable environmental, economic and social benefits of household energy conservation.

Effects of Fin Height, Fin Thickness and Reynolds Number on Heat Transfer Enhancement of Flat-Plate Thermal Collector: A Numerical Analysis

A flat-plate thermal collector combined with a PV panel also called a PV/T collector is a device that converts solar irradiation into thermal energy and electrical energy simultaneously. The unused thermal energy of the PV/T collector is absorbed by the flat-plate thermal collector. This may then contribute directly to an enhancement of the electrical efficiency of the PV/T collector. In the present study, the effect of geometry and Reynolds Number on the thermal performance of flat-plate thermal collectors is numerically investigated. Thereafter, CFD simulation is then implemented to characterize the thermal performance in terms of absorber temperature and convection heat transfer coefficient. To disturb the fluid flow pattern in this work the 45o inclined fins are attached underneath the surface of the collector model and they act as an absorber. Monthly average weather data of inlet fluid temperature and ambient temperature as well as solar irradiation level implemented in this study were obtained from the Meteorological, Climatological and Geophysical Agency of Bandarlampung regency. Several different cases have been considered by varying the fin height from 20 to 80 mm, fin thickness from 1 to 4 mm, and Reynolds number from 1500 to 6000. The results show that increasing the fin geometry (the fin thickness and fin height) and Reynolds Number reduce the flat-plate surface temperature due to the more conductive and convective heat transfer process. However, in terms of the convective heat transfer coefficient parameter, the Reynolds Number implemented has a dominant effect compared to the fin geometry. Moreover, by increasing Reynolds Number by four times, there is a decrease in the mean surface temperature by 26% and an increase in the mean convective heat transfer coefficient of 146% compared to the initial conditions

Actual issues of Russian energy sector development

The article is devoted to the consideration of the most pressing issues related to the development of the modern energy sector of Russia. Among them there are the technical obsolescence of energy production facilities, a huge amount of unused energy equipment, serious disruption of the innovation cycle in the energy industry, and inefficient management. The authors pay special attention to the difficulties associated with the ever-accelerating process of digitalization of economy in general and the energy industry in particular. The article also predicts the most probable possibilities for the emergence of environmental problems initiated by the development of renewable energy. The priority tasks for the development of the energy sector are determined. The list of the mentions tasks includes domestic power equipment competitiveness increasing; ensuring full utilization of energy capacities; restoration of the innovation process; improving the quality of strategic decisions; solving the problem of negative impacts of digitalisation.

Impact of the EPBD on Changes in the Energy Performance of Multi-Apartment Buildings in Lithuania

As per general provisions of European Directive 2010/31/EU on the energy efficiency of buildings (recast), the Lithuanian government transposed the Directive into Lithuanian national law. In the process, the Lithuanian government prepared strategic documents in the field of energy performance and renewable energy that were integrated together through the National Energy and Climate Plan for 2021–2030 (NECP). To better understand the current situation vis-à-vis energy performance, the main characteristics of buildings pertaining to the Lithuanian multi-apartment building stock, classified according to their energy performance class, are analysed and discussed in this paper. Through the exploitation of data from the national Energy Performance Certificate (EPC) register, an overview of the energy performance of the existing Lithuanian residential building stock is presented along with an analysis of the unused potential energy savings pertinent to this building category. The results obtained from the analysed data of energy consumption in buildings shows that the policies adopted over the years were successful in improving the building stock, promoting the move towards the specifications required by a Class A++ (nearly zero energy buildings—NZEB) by 2021. The results show that this was primarily achieved by a significant reduction in the thermal energy used for space heating.

Autonomous Resonance‐Tuning Mechanism for Environmental Adaptive Energy Harvesting (Adv. Sci. 3/2023)

Piezoelectric Energy Harvester A piezoelectric energy harvester (PEH) that converts unused ambient vibration energy into useful electricity can alleviate issues related to the battery maintenance and power line installation of IoT sensors. To maximize the harvesting power, the resonance frequency of the PEH should match the dominant frequency of the ambient vibrations. In article number 2205179, Kyung-Hoon Cho, Hyun-Cheol Song, and co-workers report a novel autonomous resonance-tuning (ART) PEH that autonomously adjusts its resonance frequency in accordance with ambient vibrations without any external assistance or human intervention. The PEH design methodology to implement the ART function is provided along with its real-world validation under low-frequency (<100 Hz) complex vibrations in which the acceleration and frequency change simultaneously.

Energy Management for Renewable Microgrid Cooperation: Theory and Algorithm

In the microgird (MG) system, cooperation of microgrids is a very essential issue. Hence, multi-microgrid (MMG) system has been proposed to allocate the energy and information exchange for each MG. However, the uncertainties of generations and loads are very difficult to deal with when considering the utilization of renewable energy (RE) resources. To tackle this issue, we study the optimal energy management for the cooperation of multiple MGs in this work. We propose an adaptive energy scheduling algorithm for MMG systems in order to reduce the long-term time-averaged operation cost under the constraints of renewable energy resource utilization. To deal with the unused renewable energy, virtual queues are constructed and Lyapunov framework are adopted to improvement of reliability, reduction of end-user power loss, and cultivation of renewable resource penetration. The simulation results show that the proposed algorithm is effective in coordinating multiple MGs within an MMG system so as to reduce the operation cost and improve the utilization of RE resources dramatically.

The Role Of Time-Oriented Functions based cost system In Reducing Costs Under The Strategic Cost Management Approach

Technological progress and development and the automation of production processes have made the traditional approach to cost management incompatible with these developments and the administration's need for a complex mixture of quantitative information related to the objective measurement of costs, especially indirect ones, as well as non-quantitative information related to the customer, his needs and desires, all of which reflected the need to move to an approach based on customer relationship management With a strategic dimension that takes into account the developments in the competitive environment, the current research aims to demonstrate the extent of the ability of cost technology to operate on the time-drive functions based cost as a strategic tool that is compatible with developments in the process of allocating indirect costs and the extent of its ability to provide financial and non-financial information on unutilized energy and jobs non-adding value with the aim of eliminating it by achieving a real reduction in product costs. The results of the statistical analysis indicated the highest mean (4.15), standard deviation (86%), and coefficient of variation (20.09) within the percentage weight of (73.33) that the agreement of the cost technique on the time-drive functions based cost and the strategic approach to cost management works to reallocate indirect costs based on the time vectors used to complete each function of the product, providing information to the management of the economic unit about unused energy and non-value-adding functions in a way that achieves the possibility of reducing production costs without affecting the quality of the product and the customer's desires

Metro traction power measurements sizing a hybrid energy storage system utilizing trains regenerative braking

The paper describes the measuring systems and methodology for acquiring traction power measurements on the on-board traction systems of two metro trains and three 750 V DC rectifier substations in the Athens Metro Line 2. Being part of a wider investigation to develop a Hybrid Energy Storage System (HESS), the purpose of the present measurements is to provide traction systems experimental and operational data that would assist in the understanding of the dynamic characteristics of train braking regeneration and quantify the available energy that could be stored in a super-capacitors/batteries hybrid storage system for further use, which would otherwise be wasted and consumed as heat in stations and tunnels through the trains' braking resistors. In turn the stored energy could power upon demand selected stationary electrical loads in Metro stations of a non-safety critical character (such as lighting, ventilation, pumps, etc.) leading to very significant energy savings and to a corresponding reduction of greenhouse gases. Preliminary results confirm the feasibility of the energy saving concept indicating a significant potential for the hybrid energy storage devices and subsequent energy re-use of 4000–6000 kWh/day per rectifier substation of otherwise unused train braking energy, with a typical Metro station stationary loads consumption of 2000 kWh/day.

Experimental investigation and validation of solar PV cooling for enhanced energy conversion efficiency for Indian climatic conditions

Solar Photovoltaic (PV) cells convert an average of 10 to 15% of the incident solar radiation into electricity and remaining energy is wasted as unused heat energy. The p erformance of solar PV is largely dependent on its operating temperature, which is again dependent on solar irradiation. The efficiency of solar PV reduces the higher PV temperature due to charge carrier recombination. The solar PV efficiency drops considerably wit h increasing temperature. Dust deposition on the surface of solar PV cells reduce incident energy and no technology is commercially available to mitigate the problem. The objective of the present work is to enhance the energy conversion efficiency of solar PV by adopting Front Water (FW) cooling technique. The FW cooling technique maintains the cell temperature at Standard Test Conditions (STC) irrespective of ambient air conditions and also washes away dust deposits, thereby providing maximum energy conversion efficiency specified by the cell manufacturer during the operation with increased lifecycle of solar cells. The experiment was carried out on a 100 W solar panel for a period of 2 weeks and data acquisition system with Arduino controller was used to analyze and maintain STC of the panel to obtain maximum power. The mathematical model of the system was analyzed and obtained results were in good agreement with the experimental measurements. The solar PV panel with FW cooling yielded an efficiency improvement of 9% with 17 W of increased power output at Maximum Power Point (MPP). MATLAB Simulink software is used to model t he FW cooling technique. The model is able to predict the power generated by the solar PV cells for the given irradiance with and without cooling. The developed model can now be utilized to design cooling systems for larger installation of solar PV systems.