Journal of Thermal Energy Systems

Performance Analysis of Multi-Pressure Refrigeration System Using R12, R134 & R22 Refrigerant

Sumit Kumar Pandey — 2024-02-29

Three evaporators having their capillary for expansion in vapour compression refrigeration systems have been considered for experimentation where a single compressor having a single condenser is used. A hand-operated valve is used for controlling the mass flow rate. Refrigerant R-12, R134 and R-22 have been used to check the performance of Multiple VC systems for different conditions, where it was found that the performance of R22 is much better than R12 and R134. At present R22 is not used because of its chemical composition which can create problems for the ozone layer in the long term but replacement of R22 is available today with the R400 series. By using this type of system one evaporator can be used as a deep freezer, one evaporator as a frost-free and the other can be used as a normal refrigerator. A compressor with a capacity of 1.0 Tonnes is used. The heavy condenser is used which is generally used in air conditioning systems. The cooling capacity of each evaporator is controlled by an input valve provided, while the compressor and condenser use single-input, single-output point. This appliance has three compartments each having a common access door. The first evaporator is for the first compartment operating at the first pressure level, the second evaporator is for the second compartment operating at the second pressure level and the third evaporator is for the third compartment operating at the third pressure level. By changing the mass flow rate of each evaporator, we can produce different temperatures in each evaporator.

Experimental & Simulation Analysis of Convective Hot Air-Drying Chamber Used for Blood Bag Drying Operation

Shibulal S L — 2024-03-05

This study aimed to analyse the convective heat transfer rate in a hot air-drying chamber (tray type) used for blood bag manufacturing. After steam sterilization in an autoclave, blood bags retain moisture in the form of water droplets inside and outside the Polypropylene (PP) covers. Currently, only 45-50% of the products are acceptable after the drying operation, with more than 50% still containing moisture. Experimental analysis was conducted to calculate the drying efficiency, temperature distribution, and Relative Humidity (RH) inside the drying chamber. Drying experiments were performed under different drying hold temperatures (60°C, 65°C, 70°C, and 75°C) with uniform air velocity. The optimal drying hold temperature for blood collecting bags was found to be 70°C, resulting in a 65.53% acceptance rate of the product. The convective heat transfer coefficient was calculated from experimental data and found to range from 35 to 45 W/m²K. The drying efficiency of the system for the optimum temperature cycle (70°C) is 66.42%. A simulation study was conducted to obtain the air flow pattern, air velocity, and temperature distribution inside the drying chamber and among the product trays. The case with baffles placed normally to the X-axis (case 1) showed non-uniform velocity distribution inside the chamber, with an average convective heat transfer coefficient (h) of 36.36 W/m²K and a total heat transfer rate (Q) of 5819 W for the entire tray. In case 2, where the baffles were positioned at a 45° angle, the values of h and Q were 39.42 W/m²K and 6422 W, respectively. Similarly, in case 3, where the baffles were positioned at a 45° angle in a zig-zag manner at the chamber's inlet, enhanced drying rates and more uniform velocity distributions were achieved, with h and Q values of 45.39 W/m²K and 7544 W, respectively. The energy consumed for one cycle of operation was determined as 752.48 kWh, and the Specific Energy Consumption (SEC) was calculated as 54.60 kWh/kg at 70°C, 68.60 kWh/kg at 65°C, and 80.47 kWh/kg at 60°C based on the moisture removal rate. In conclusion, this study suggests possible changes to the chamber settings to improve drying performance and velocity distributions, leading to higher product acceptance rates and more efficient drying processes.

A Comprehensive Review of Advancements in Automotive Engine Cooling: Integrating Radiator and Air Conditioning Systems for Enhanced Performance

Sambhav Jain — 2024-03-07

This comprehensive review explores recent advancements in the integration of radiator and air conditioning systems for automotive engine cooling, aiming to enhance overall performance. The automotive industry is witnessing a paradigm shift in thermal management strategies to meet the increasing demands for efficiency, sustainability, and environmental responsibility. In the realm of radiator advancements, we delve into cutting-edge materials, design configurations, and manufacturing processes. Noteworthy innovations contributing to improved heat dissipation, corrosion resistance, and overall efficiency are scrutinized, providing a foundation for understanding the evolving landscape of radiator technology. The integration of radiator and air conditioning systems presents unique challenges. This review identifies and analyzes these challenges while concurrently exploring the engineering solutions and technological breakthroughs that have been devised to address them. The focus is on optimizing the overall system to achieve superior performance and efficiency. Energy-efficient cooling strategies represent a crucial aspect of our investigation, encompassing smart control algorithms, thermal management integration, and the utilization of advanced materials. By evaluating these strategies, we aim to unveil approaches that optimize energy consumption in engine cooling systems without compromising performance. Environmental considerations play a pivotal role in our review, assessing the impact of current technologies on the ecosystem. Sustainable practices, the adoption of eco-friendly refrigerants, and initiatives to reduce the carbon footprint emerge as integral components in the pursuit of environmentally responsible automotive thermal management. Ultimately, this review synthesizes key findings, providing valuable insights into the current state and future trajectories of integrated radiator and air conditioning systems for automotive engine cooling. The analysis spans advancements in radiator design, integration challenges, energy-efficient strategies, and environmental considerations, and outlines potential trends shaping the future of vehicle thermal management.

Experimental Investigation on Performance of a Double Pass Solar Air Heater Using Black Coated Porous Wire Mesh as Packed Bed in Rajshahi Division

Md. Mukul Uddin — 2024-02-06

In this experimental study, a double pass Solar Air Heater (SAH) utilizing black coated porous wire mesh as a packed bed was subjected to rigorous analysis. The research focused on assessing the system's performance using efficiency as a key metric, while also considering the temperature differential between the inlet airflow at ambient conditions and outlet airflows. Throughout the investigation, solar intensity was continuously monitored over a day to gauge the availability of solar energy at the experimental location, demonstrating satisfactory levels. Additionally, the heat-absorbing characteristics of the packed bed were scrutinized under three distinct flow rates (0.0115 kg/s, 0.028 kg/s, and 0.038 kg/s). The findings demonstrated that with an increase in flow rate, the temperature difference between the incoming and outgoing airflows exhibited a decrease. Nevertheless, this was accompanied by a noteworthy enhancement in overall system efficiency. Notably, the maximum efficiency exhibited a substantial improvement with increasing flow rate, reaching an impressive gain of 120% to 150%. Moreover, the performance of the solar collector exhibited a characteristic trend of increasing to decreasing throughout the whole day, corresponding to the varying solar intensity levels.

Numerical Analysis of Heat Transfer in Stainless Steel Blade with Short Fin Configurations Using C Programming

Dhakshna Moorthy D — 2024-05-01

This research focuses on the computational analysis of heat flow at the root of a stainless steel blade equipped with short fins, with the assumption of negligible heat loss. The study aims to employ Artificial Intelligence (AI) techniques in C programming to model and simulate the heat transfer phenomenon. By utilizing C's numerical computing libraries and AI algorithms, such as machine learning and optimization techniques, the objective is to accurately predict the heat distribution at the blade root under various operating conditions. This research contributes to the advancement of computational methods for heat transfer analysis in engineering applications, particularly in the optimization of blade designs for enhanced thermal performance. This study delves into the intricate dynamics of thermodynamics fins and heat transfer phenomena, with a focus on utilizing C programming for analysis and exploration. Fins, as integral components in engineering systems, play a pivotal role in enhancing heat dissipation efficiency by increasing surface area. The research investigates the fundamental principles governing heat transfer mechanisms, encompassing conduction, convection, and radiation, within the context of fin structures. Mathematical models, including the one-dimensional heat conduction equation, serve as foundational frameworks for understanding heat transfer in fins. Leveraging C's robust numerical computing libraries, such as NumPy and SciPy, enables the implementation of Finite Difference Methods (FDM) for solving heat conduction equations numerically. Additionally, the study explores the application of Computational Fluid Dynamics (CFD) simulations to provide comprehensive insights into fluid flow and heat transfer interactions around fins. Furthermore, optimization techniques facilitated by C's optimization libraries are employed to optimize fin designs for maximizing heat transfer efficiency. Through C programming, this research endeavours to advance our understanding of thermodynamics fins and heat transfer processes, offering practical insights for engineering applications and system design optimization.