scholarly journals Numerical Simulation Study of Three-Dimensional Flow Field on Roots- Type Power Machine Based on Dynamic Mesh Technique

2015 ◽  
Vol 9 (1) ◽  
pp. 402-410
Author(s):  
Xiao Yanjun ◽  
Liu Yuxiang ◽  
Wang Dayuan ◽  
Li Chunxia
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Operating Conditions ◽  
Waste Heat Recovery System ◽  
Dynamic Mesh Technique ◽  
Power Machine ◽  
Recovery System ◽  
Type Power ◽  
Mesh Technique

Expander which drives an electromotor to generate electricity is the core of low-temperature waste heat recovery equipment. At present, domestic expanders on waste heat recovery system mostly arise from exploration, research and improvement on the existing models of screw expanders and scroll expanders, which have complex structures and high costs. For overcoming the shortcomings mentioned above, a new roots-type power machine is researched and designed. In this paper, the working fluid of low pressure waste heat is stimulated according to both the different operating conditions and the different intake and exhaust pressure and flow, and the changing process of internal flow field is simulated over the time period using dynamic mesh technique when the power machine is in rotating work. Besides, the pressure field, velocity field and graph of mass flow rate are analyzed with the simulation results, thus obtaining the conclusion of optimum operating conditions of the roots-type power machine to guide selection method in practice, that is, selecting appropriate roots-type power machines according to different types of waste heat in industrial production. These efforts can therefore provide strong theoretical guidance and foundation for the subsequent engineering practice of waste heat recovery system on roots-type power machine, and can have a profound impact on further recovery and utilization of low-grade energy.

Design and Performance of a Fuel Cell Plant Heat Recovery System

2007 ◽  
Author(s):  
Robert G. Ryan ◽  
Tom Brown
Keyword(s):  
Fuel Cell ◽  
Latent Heat ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Operating Conditions ◽  
Hot Water ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

A 1 MW Direct Fuel Cell® (DFC) power plant began operation at California State University, Northridge (CSUN) in January, 2007. This plant is currently the largest fuel cell plant in the world operating on a university campus. The plant consists of four 250 kW DFC300MA™ fuel cell units purchased from FuelCell Energy, Inc., and a waste heat recovery system which produces dual heating hot water loops for campus building ventilation heating, and domestic water and swimming pool heating water for the University Student Union (USU). The waste heat recovery system was designed by CSUN’s Physical Plant Management and engineering student staff personnel to accommodate the operating conditions required by the four individual fuel cell units as well as the thermal energy needs of the campus. A Barometric Thermal Trap (BaTT) was designed to mix the four fuel cell exhaust streams prior to flowing through a two stage heat exchanger unit. The BaTT is required to maintain an appropriate exhaust back pressure at the individual fuel cell units under a variety of operating conditions and without reliance on mechanical systems for control. The two stage heat exchanger uses separate coils for recovering sensible and latent heat in the exhaust stream. The sensible heat is used for heating water for the campus’ hot water system. The latent heat represents a significant amount of energy because of the high steam content in the fuel cell exhaust, although it is available at a lower temperature. CSUN’s design is able to make effective use of the latent heat because of the need for swimming pool heating and hot water for showers in an adjacent recreational facility at the USU. Design calculations indicate that a Combined Heat and Power efficiency of 74% is possible. This paper discusses the integration of the fuel cell plant into the campus’ energy systems, and presents preliminary operational data for the performance of the heat recovery system.

scholarly journals Advance Exergo-Economic Analysis of a Waste Heat Recovery System Using ORC for a Bottoming Natural Gas Engine

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 267 ◽  
Author(s):  
Guillermo Valencia Ochoa ◽  
Jhan Piero Rojas ◽  
Jorge Duarte Forero
Keyword(s):  
Heat Exchanger ◽  
Economic Analysis ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Operating Conditions ◽  
Cost Rate ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

This manuscript presents an advanced exergo-economic analysis of a waste heat recovery system based on the organic Rankine cycle from the exhaust gases of an internal combustion engine. Different operating conditions were established in order to find the exergy destroyed values in the components and the desegregation of them, as well as the rate of fuel exergy, product exergy, and loss exergy. The component with the highest exergy destroyed values was heat exchanger 1, which is a shell and tube equipment with the highest mean temperature difference in the thermal cycle. However, the values of the fuel cost rate (47.85 USD/GJ) and the product cost rate (197.65 USD/GJ) revealed the organic fluid pump (pump 2) as the device with the main thermo-economic opportunity of improvement, with an exergo-economic factor greater than 91%. In addition, the component with the highest investment costs was the heat exchanger 1 with a value of 2.769 USD/h, which means advanced exergo-economic analysis is a powerful method to identify the correct allocation of the irreversibility and highest cost, and the real potential for improvement is not linked to the interaction between components but to the same component being studied.

An investigation of marine waste heat recovery system based on organic Rankine cycle under various engine operating conditions

2018 ◽  
Vol 233 (2) ◽  
pp. 586-601
Author(s):  
Mehmet Akman ◽  
Selma Ergin
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Pollution Prevention ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

Energy-saving, stricter regulations on pollution prevention, increasing energy efficiency and reducing operational costs have become common and primary issues for maritime industry, recently. One of the methods to improve these requirements onboard is to use a waste heat recovery system based on organic Rankine cycle. In this article, organic Rankine cycle–based waste heat recovery system for a chemical/oil tanker is investigated at different engine operating conditions by thermodynamic, environmental and economic analyses. The jacket cooling water, scavenge air, exhaust gas and combination of these three sources are used as the waste heat sources. R245fa is selected as the working fluid. The performance parameters of four different organic Rankine cycle–based waste heat recovery systems integrated with the main engine of the tanker are calculated and presented. The results show that by using the organic Rankine cycle–based waste heat recovery system onboard, it is possible to increase the overall thermal efficiency of the ship’s power plant by more than 6% and the combined organic Rankine cycle–based waste heat recovery system can meet all navigation electricity demand when the engine is operated at 82% maximum continuous rating or higher engine loads. In comparison with other organic Rankine cycle–based waste heat recovery systems, the combined organic Rankine cycle–based waste heat recovery system has the highest capital cost, but it has the shortest payback time. Furthermore, this system can reduce the ship emissions by about 6.9%.

ANALYSIS ON THE EFFECT OF NANO PARTICLES IN WASTE HEAT RECOVERY SYSTEM USING HEAT PIPES BY RSM

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Gunabal S
Keyword(s):  
Response Surface Methodology ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Heat Pipes ◽  
Filling Ratio ◽  
Nano Particles ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

Waste heat recovery systems are used to recover the waste heat in all possible ways. It saves the energy and reduces the man power and materials. Heat pipes have the ability to improve the effectiveness of waste heat recovery system. The present investigation focuses to recover the heat from Heating, Ventilation, and Air Condition system (HVAC) with two different working fluids refrigerant(R410a) and nano refrigerant (R410a+Al2O3). Design of experiment was employed, to fix the number of trials. Fresh air temperature, flow rate of air, filling ratio and volume of nano particles are considered as factors. The effectiveness is considered as response. The results were analyzed using Response Surface Methodology

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