Heat Transfer Calculations for Cooling System Performance Prediction and Experimental Validation

2011 ◽  
Author(s):  
Manvendra M. Umekar ◽  
D. Govindaraj
Keyword(s):  
Heat Transfer ◽  
Performance Prediction ◽  
System Performance ◽  
Experimental Validation ◽  
Cooling System

Micro- and Nano- Technologies: Roadmap Enabling More Compact, Lightweight Thermoelectric Power Generation and Cooling Systems

2011 ◽  
Author(s):  
Terry J. Hendricks
Keyword(s):  
Heat Transfer ◽  
Power Generation ◽  
High Temperature ◽  
System Performance ◽  
Energy Recovery ◽  
Cooling System ◽  
System Level ◽  
Cooling Systems ◽  
Thermal Transfer ◽  
Micro Technology

Advanced thermoelectric (TE) energy recovery and cooling systems have critical benefits in transportation, industrial process, and military applications because of rising or uncertain energy costs and subsequent need for energy efficiency, geopolitical uncertainties impacting basic energy supplies worldwide, and the need for electrified, distributed cooling and heating systems in automotive applications. Advanced TE energy recovery and cooling technologies will require high-performance heat transfer characteristics to achieve system performance targets and requirements. However, TE energy recovery systems generally have high-temperature thermal transfer requirements (i.e., as high as 750–800 °C), while TE cooling systems require low temperature thermal transfer (i.e., 25 °C – 100 °C). Investigations have compared system power and cooling benefits and system thermal integration challenges of energy recovery and cooling systems using microchannel heat exchangers to provide high heat transfer performance in both high-temperature, high-enthalpy energy streams and low-temperature cooling streams. This work explores the roadmap and vision for using micro-technology solutions integrated with advanced thermoelectric materials in advanced TE power generation and cooling systems. Integrated system-level TE power generation and cooling system analyses demonstrate that inter-related system-level requirements on weight, volume, and performance lead to derived requirements for micro-technology solutions. Nano-technologies and micro-technologies will be presented that demonstrate where and how these technologies impact TE system designs. Of course, micro-technology manufacturing cost is critical in all energy recovery and cooling applications. Recent progress in microtechnology cost-modeling elucidates and quantifies key cost-manufacturing interdependencies, relationships, and sensitivities that will be explored in this presentation. This provides critical information on manufacturing processes, production volume dependence, material selections, and ultimately pathways forward leading to low-cost microtechnology heat and mass transfer devices that improve advanced TE energy recovery and cooling system performance (specifically including weight and volume impacts).

Experimental Validation of PRHR System for Low Temperature and Low Pressure Pool-Type LWR Using Thermosyphon

2014 ◽  
Author(s):  
Jangsik Moon ◽  
Byung-Hyun You ◽  
Yong Hun Jung ◽  
Yong Hoon Jeong
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Experimental Validation ◽  
Cooling System ◽  
Low Pressure ◽  
Calculation Model ◽  
Working Fluid ◽  
Primary System ◽  
Two Phase ◽  
Pool Type

PRHR system for low temperature and low pressure pool-type LWR, AHR400 is designed by two-phase closed thermosyphon and experimental validation is conducted. AHR400 is dedicated only to heat generation used in seawater desalination and operation temperature and pressure. LBLOCA is not considered as DBA due to no pipeline in primary system. There are LOHS and SBO for DBAs and PRHR system reduces damage during DBAs. Design of the PRHR system follows Direct Reactor Auxiliary Cooling System (DRACS) type. Two-phase closed thermosyphon, which uses phase change of working fluid, is applied to the PRHR system and the heat transfer in thermosyphon are analyzed by thermal resistance calculation model. Experimental thermosyphon that has similar thermal condition with the thermosyphon in designed PRHR system was explored for validation. The results show that the evaporation model overestimates heat transfer rate on the evaporator region.

Heat Transfer Characteristics of Downward Facing Hot Horizontal Surfaces Using Mist Jet Impingement

2017 ◽  
Author(s):  
Ashutosh Kumar Yadav ◽  
Parantak Sharma ◽  
Avadhesh Kumar Sharma ◽  
Mayank Modak ◽  
Vishal Nirgude ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Cooling System ◽  
Water Pressure ◽  
Jet Impingement ◽  
Surface Heat ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Transfer Characteristics

Impinging jet cooling technique has been widely used extensively in various industrial processes, namely, cooling and drying of films and papers, processing of metals and glasses, cooling of gas turbine blades and most recently cooling of various components of electronic devices. Due to high heat removal rate the jet impingement cooling of the hot surfaces is being used in nuclear industries. During the loss of coolant accidents (LOCA) in nuclear power plant, an emergency core cooling system (ECCS) cool the cluster of clad tubes using consisting of fuel rods. Controlled cooling, as an important procedure of thermal-mechanical control processing technology, is helpful to improve the microstructure and mechanical properties of steel. In industries for heat transfer efficiency and homogeneous cooling performance which usually requires a jet impingement with improved heat transfer capacity and controllability. It provides better cooling in comparison to air. Rapid quenching by water jet, sometimes, may lead to formation of cracks and poor ductility to the quenched surface. Spray and mist jet impingement offers an alternative method to uncontrolled rapid cooling, particularly in steel and electronics industries. Mist jet impingement cooling of downward facing hot surface has not been extensively studied in the literature. The present experimental study analyzes the heat transfer characteristics a 0.15mm thick hot horizontal stainless steel (SS-304) foil using Internal mixing full cone (spray angle 20 deg) mist nozzle from the bottom side. Experiments have been performed for the varied range of water pressure (0.7–4.0 bar) and air pressure (0.4–5.8 bar). The effect of water and air inlet pressures, on the surface heat flux has been examined in this study. The maximum surface heat flux is achieved at stagnation point and is not affected by the change in nozzle to plate distance, Air and Water flow rates.

scholarly journals Numerical Evaluation of a HVAC System Based on a High-Performance Heat Transfer Fluid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3298
Author(s):  
Gianpiero Colangelo ◽  
Brenda Raho ◽  
Marco Milanese ◽  
Arturo de Risi
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Cooling System ◽  
Electrical Energy ◽  
Simulation Software ◽  
Heat Transfer Fluid ◽  
Hvac System ◽  
Dynamic Simulations ◽  
Heating And Cooling ◽  
The University

Nanofluids have great potential to improve the heat transfer properties of liquids, as demonstrated by recent studies. This paper presents a novel idea of utilizing nanofluid. It analyzes the performance of a HVAC (Heating Ventilation Air Conditioning) system using a high-performance heat transfer fluid (water-glycol nanofluid with nanoparticles of Al2O3), in the university campus of Lecce, Italy. The work describes the dynamic model of the building and its heating and cooling system, realized through the simulation software TRNSYS 17. The use of heat transfer fluid inseminated by nanoparticles in a real HVAC system is an innovative application that is difficult to find in the scientific literature so far. This work focuses on comparing the efficiency of the system working with a traditional water-glycol mixture with the same system that uses Al2O3-nanofluid. The results obtained by means of the dynamic simulations have confirmed what theoretically assumed, indicating the working conditions of the HVAC system that lead to lower operating costs and higher COP and EER, guaranteeing the optimal conditions of thermo-hygrometric comfort inside the building. Finally, the results showed that the use of a nanofluid based on water-glycol mixture and alumina increases the efficiency about 10% and at the same time reduces the electrical energy consumption of the HVAC system.

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