BITS Faculty Publications

Permanent URI for this communityhttp://localhost:4000/handle/123456789/1867

Browse

Subject: search.filters.subject.Energy efficiency

Search Results

Now showing 1 - 10 of 36
  • No Thumbnail Available
    Item
    A comprehensive review on composite phase change materials for sustainable thermal energy solutions: Advances and barriers
    (Elsevier, 2025-10) Bhattacharyya, Suvanjan
    Composite Phase Change Materials (CPCMs) have gained significant attention for their potential in thermal energy storage (TES) due to their high latent heat capacity. These materials offer a promising solution for addressing global energy challenges, especially in renewable energy applications. This review summarizes recent advances in CPCMs, discusses existing challenges, and suggests future research directions. While phase change materials (PCMs) are key for thermal management due to their high energy density, they face limitations such as low thermal conductivity, leakage during phase transitions, and poor stability. To address these issues, additives like nanoparticles, expanded graphite, and polymers have been incorporated into CPCMs, improving thermal conductivity, stability, and energy storage efficiency. Research has shown that carbon-based nanomaterials can enhance thermal conductivity by up to 137% and improve thermal cycling durability. Innovative CPCM formulations, such as eutectic mixtures and hybrid composites, help overcome phase stability and leakage issues. Microencapsulation has also made strides, enhancing PCM containment and functionality, with dual-layer encapsulated CPCMs maintaining latent heat efficiency for over 200 cycles with minimal degradation. Nanomaterials like graphene and carbon nanotubes further reinforce thermal properties. CPCMs are widely used in solar thermal systems, building temperature regulation, and industrial waste heat recovery. In concentrated solar power systems, CPCMs have shown outstanding thermal storage capabilities and efficiencies, with some surpassing 90% solar-to-thermal conversion. Despite these advances, challenges remain, including high production costs, material degradation, and environmental concerns. Future research should focus on improving stabilization, scalability, and eco-friendly materials. The review concludes by highlighting research gaps and the potential of integrating CPCMs with smart technologies for dynamic thermal management, underscoring the need for cross-disciplinary strategies to optimize CPCM performance for broader adoption.
  • No Thumbnail Available
    Item
    Prospects of open cathode fuel cells in future powertrains
    (Springer, 2025-08) Verma, Saket
    Fuel cell technology shows great potential as an eco-friendly alternative to conventional internal combustion engines. Conventional internal combustion engines only manage efficiencies of 20–30%, whereas fuel cells can attain efficiencies of up to 40–60%. In contrast to internal combustion engines (IC engines), which release pollutants into the air and worsen global warming, fuel cells only release water (or vapour) in the exhaust. Despite the fast advancements in fuel cell technology, it still lags IC engines in terms of maturity and encounters challenges such as low life, high costs, unreliability, and a lack of hydrogen refuelling infrastructure. Furthermore, fuel cell vehicles are expensive because of the high price of fuel cell stacks and hydrogen storage systems. Therefore, improving fuel cell performance and reducing costs are of utmost importance to fully utilize its potential and make it practical in future powertrains. A noteworthy advancement in clean energy technologies is open cathode fuel cells that generate power reliably and in an eco-friendly manner. There is no longer a requirement for compressed oxygen or air supply systems in open cathode fuel cells, as they offer an exposed cathode surface that allows direct access to ambient air, in contrast to typical closed cathode designs. Open cathode fuel cells are a promising alternative for several renewable energy applications due to their dependence on natural convection for oxygen delivery, which simplifies the system structure and reduces complexity. Moreover, open cathode fuel cells are more efficient at converting energy and provide more power when operated at higher temperatures. Their exceptional power density and efficiency make them ideal for transportation and distributed power generation, among other uses. However, there are still uncertainties that prevent this technology from being widely used, such as managing humidity, temperature, and durability in exposed locations. This chapter provides an overview of open cathode fuel cell technology, including its background, current uses, and potential future developments. In addition, it outlines a strategy for optimizing and characterizing the performance of open cathode fuel cells using a simplified electrochemical–thermodynamic modelling approach.
  • No Thumbnail Available
    Item
    Performance evaluation of natural refrigerant pairs R744/R717 and R744/R290 in cascade systems with IHX and economizer configurations for individual quick freezers
    (Springer, 2025-07) Dasgupta, Mani Sankar
    This study presents a comprehensive analysis of the effectiveness of two different sub cooling arrangements in natural refrigerant cascade systems (CRS) R744/R717 and R744/R290 having solitary evaporator maintained at −45°C, which is an individual quick freezer (IQF) for seafood application. The assessed sub-cooling configurations, denoted as CRSI and CRSE, involve specific arrangements: CRSI incorporates an intermediate heat exchanger (IHX) within the high-temperature circuit (HTC), whereas CRSE integrates an economizer arrangement within a screw compressor in the HTC. Performance comparisons are drawn with a conventional R404A system under an ambient temperature of 40°C. The polytropic compressor equations are employed to model system performance under design conditions. The cooling load data from a seafood processing unit in Kochi, Kerala, India is utilized. It is found that for both R744/R717 and R744/R290 CRSs, the CRSE configuration shows a higher COP compared to the CRSI configuration. The CRSE setup with R744/R717 refrigerant had the best cooling COP of 1.06, while the second highest COP is found for CRSE R744/R290, reaching 1.03. The COP improvement obtained is 50.5 and 46.7% over the conventional R404A system. The heat recovery potential of the proposed CRSs is lower than the R404A system. R744/R717 in CRSI configuration have higher heat recovery potential than other CRSs. However, the overall (combined heating cooling) COP of R744/R717 in the CRSE configuration was found to be the highest and is 43% higher than the R404A system. The annual energy consumption (AEC) and total equivalent warming impact (TEWI) are also compared and it is found that adoption of R744/R717 CRSE can lower the AEC and TEWI in an IQF application by 33.6 and 68.8% respectively. Further, the economic analysis of the systems shows that although the CRS systems require a higher initial investment, the same can be mitigated by lower operating costs and reduced environmental penalty costs.
  • No Thumbnail Available
    Item
    Design and simulation of energy efficient OLEDS for flexible electronics applications
    (IEEE, 2025-05) Gupta, Navneet
    Organic Light Emitting Diodes (OLEDs) are a promising technology known for their thin, energy-efficient, and high-quality light emission, making them ideal for displays and lighting applications. Flexible OLEDs, an emerging development from conventional rigid OLEDs, can be integrated into curved or bendable surfaces, enabling new design possibilities in wearable electronics, foldable screens, and innovative lighting solutions. In this work, we designed and simulated a multilayer OLED structure using TCAD (Technology Computer-Aided Design) software, focusing on material selection for the emission layer to optimize energy efficiency and performance. Three candidate materials—Alq3, PPV, and PFO—were evaluated, with PFO demonstrating superior luminescent power and energy efficiency. Through geometry optimization of the PFO layer, we achieved an energy efficiency of 14.08%, highlighting its potential as a suitable alternative to Alq3 for flexible OLED applications.
  • No Thumbnail Available
    Item
    Sustainable marine surveillance sensor network aided by swipt-enabled auvs
    (IEEE, 2025-08) Tripathi, Sharda
    Oceans are vital for Earth's climate stability, oxygen production, and as sources of food and energy for countless organisms. However, human-induced climate change significantly disrupts marine ecosystems, emphasizing the need for advanced underwater monitoring. The Internet of Underwater Things (IoUT), composed of marine sensor networks, offers a promising solution, nonetheless, challenges such as limited communication range and constrained power supplies. To address these issues, this work proposes using simultaneous wireless information and power transfer (SWIPT) from autonomous underwater vehicles (AUVs) to enhance sensor node efficiency. We formulate an integer linear programming (ILP) problem aimed at optimizing AUV trajectories through marine sensor networks, minimizing propulsion energy and mission duration while ensuring adequate energy harvesting at each node. The problem is proven to be NP-hard, resembling the well-known traveling salesman problem (TSP). Further, we introduce CLEAR, a multi-agent deep-Q-network (DQN) framework that effectively selects optimal path for AUV-based data muling. Experimental results demonstrate that CLEAR significantly improves network energy-efficiency, reduces mission duration, boosts harvested energy, and decreases age-of-information (AoI) of sensor data.
  • No Thumbnail Available
    Item
    Towards low carbon economy: role of green finance in climate change mitigation
    (Elsevier, 2024) Giri, Arun Kumar
    In leveraging carbon capture, carbon taxation, technological innovations, and energy transition to tackle environmental degradation in pursuit of the COP-28 vision, there is also a need to consider the viability of green financing to facilitate climate mitigation and achieve a low-carbon economy. The present study investigates the pivotal role green finance can play in mitigating the effects of climate change. The findings from the LCM OLS, LCM FMOLS, and LCM dynamic ARDL model estimators showed that green financing and energy efficiency have a negative and significant effect on climate mitigation. Although the long-run outcome of the dynamic ARDL regression revealed that they have a negative and insignificant effect on climate mitigation, it goes on to suggest that with proper policies in place to sustain energy efficiency and green financing, climate mitigation will be sustained in the long run. While economic growth and technological innovation have a positive effect on climate mitigation, this is indeed expected because economic growth at the initial stage of industrialization encourages environmental destruction. The recommendations are to increase green financing and the adoption of energy-efficient technologies and fuels.
  • No Thumbnail Available
    Item
    Energy efficient data communication for WSN based resource constrained IoT devices
    (Elsevier, 2024-10) Haribabu, K.
    In the Internet of Things (IoTs) and wireless sensor networks (WSNs), improving security and energy efficiency are key concerns. Clustering, which involves managing cluster heads, plays a pivotal role in extending network lifetime. The selection of a cluster head, responsible for data transfer between nodes, is a key aspect of network management. This paper proposes two variants of a novel algorithm designed for energy efficient communication in a resource constrained IoT environments. One variant considers remaining energy, distance, and node degree for cluster head selection, while the other focuses on remaining energy and distance only. Including node degree ensures cluster heads do not waste energy by remaining idle or performing unnecessary tasks such as the cluster head selection process in every round. The authors tested these variants against several well known algorithms using MATLAB simulation environment, evaluating factors such as operating nodes, number of clusters, transmission energy, and remaining energy. The proposed algorithm extends network lifetime by maintaining more operating nodes for longer, not changing clusters or cluster heads frequently, minimizing energy consumption for transmission, and conserving more remaining energy. Consequently, the proposed algorithm outperforms existing approaches by addressing issues like zero cluster head selection, compulsory cluster head selection in every round, avoiding cluster heads that connect to no nodes, and preventing network destabilization due to unnecessary re-elections.
  • No Thumbnail Available
    Item
    An energy efficient data dissemination and information retrieval scheme for VANET
    (IEEE, 2016-02) Dua, Amit
    With the increasing scarcity of resources, the need for energy efficient solutions has reached its pinnacle. Vehicular ad hoc networks (VANETs) is no exception and there is a need for exclusive solutions for energy efficient data dissemination and information retrieval. The proposed scheme classifies the vehicles into different types based on their storage and computation capacity. Cluster heads (CHs) are elected for each energy zone according to type of vehicle, and act as information center. Apart from CHs, the dissemination of data and access of information in efficient and correct manner is made possible with the help of vehicles having high processing capability. The broadcast storm problem that consumes high energy in terms of bandwidth, is solved using proposed game theoretic decision model. The proposed model gives suggestion to vehicles whether to disseminate the information or not based on the current energy situation of the network. Simulation results prove that the proposed model saves energy and time by minimizing the overhead and delay. The network energy is efficiently utilized by achieving higher packet delivery ratio and lower delay than other state-of-art protocols.
  • No Thumbnail Available
    Item
    Passive solar design for energy efficiency in buildings in composite climate
    (IOP, 2019) Gupta, Rajiv
    Renewable energy sources offer an unlimited supply of energy. Solar energy can be utilized to supplement energy needs of a building either passively or actively. It is feasible to reduce consumption of energy usage for heating, cooling and lighting requirements of a building by adopting a climate sensitive approach for design of building elements like static sunshade, wall and roof. To study the effect of passive building elements in composite climate zone, four rooms were designed with a different combination of type of static sunshade, wall and roof. The static sunshade and brick cavity wall with brick projections were designed using sunpath diagram and shadow angles. Air cavity was introduced in the reinforced cement concrete (RCC) roof by laying hollow stoneware pipes. This paper presents theoretical and simulation studies to compare thermal performance of the four rooms. Theoretically, the four rooms were compared by steady state method based on total heat load in every month and on representative days in different seasons throughout the year. The extreme and most frequently occurring temperature values (mode) in every season were identified by obtaining the frequency distribution of the outdoor air temperature with the software SPSS Statistics (IBM Corp. 2012). Results showed that room with designed passive elements gained minimum heat in summer and moderate summer, while it lost minimum heat in winter and moderate winter. This shows the effectiveness of the designed passive elements in insulating the room interiors from the extreme climatic conditions. The rooms were also simulated using software Autodesk Ecotect Analysis 2011 and their performance was compared on a typical day in each month. Results showed that this software can be helpful for preliminary design to get an idea about the room performance that can help to create thermally comfortable indoor environment for the well being of occupants.
  • No Thumbnail Available
    Item
    Environment-Aware Green UAV-Assisted, CubeSat Communication Network Energy Efficiency and Outage Probability Analysis
    (IEEE, 2024-08) Bitragunta, Sainath
    Rapid advancements in internet-of-things (IoT), unmanned aerial vehicles (UAVs), and energy harvesting (EH) technologies can be leveraged to design and develop green and reliable cooperative Cube satellite communication (CSC) systems and networks. In this work, we propose a novel cooperative CSC system model comprising green UAVs as intelligent relays equipped with IoT sensors, intelligent processing and EH modules, and transceivers. Using a novel and intelligent probabilistic transmission policy (PTP) that we propose, CubeSats can conserve energy by deactivating transmissions in unfavorable weather conditions based on control signals from the smart UAV via a telemetry link. We extend this model to include multiple CubeSats and analyze it by deriving and evaluating network energy efficiency and its lower bound. Our numerical plots show that the proposed PTP significantly outperforms the continuous transmission policy (CTP). At a specific transmission probability of 0.125, PTP is 40 times more energy efficient than CTP. We extend the work and develop a novel and insightful performance analysis for energy efficiency outage (EEO) probability. Specifically, we derive closed-form approximate expressions for EEO probability and present numerical results. Furthermore, we analyze the performance of clustered CSC networks and present numerical results to assess EEO probability, providing valuable insights for future large-scale green CSC network design and deployment.