Numerical Performance Comparison of Different Tube Cross–Sections for Heat Recovery From Particle-Laden Exhaust Gas Streams

In this study, energetic based fluid selection for a solid oxide fuel cell-organic rankine combined power system is investigated. 9 dry organic fluids with varied critical temperatures are chosen and their corresponding ORC cycle performances are evaluated at different turbine inlet temperatures and exhaust gas temperature (waste heat source) from the upper cycle. It is found that actual ORC cycle efficiency for each fluid strongly depends on the waste heat recovery performance of the heat recovery vapor generator. Exhaust gas temperature determines the optimal fluid which yields the highest efficiency.

Download Full-text

Prediction and Performance of Compact Latent Heat Recovery Heat Exchanger With Small Diameter Tubes

ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference, Volume 2 ◽

10.1115/ht2007-32071 ◽

2007 ◽

Cited By ~ 1

Author(s):

Masahiro Osakabe

Keyword(s):

Heat Exchanger ◽

Power System ◽

Latent Heat ◽

Heat Recovery ◽

Small Diameter ◽

Cooling Water ◽

Prediction Method ◽

Outer Diameter ◽

Exhaust Gas ◽

And Performance

The most part of energy losses in power system such as fuel cells is due to the heat released by the exhaust gas to atmosphere. The exhaust gas consists of non-condensable gas and steam with sensible and latent heat. As a lot of latent heat is included in the exhaust gas, its recovery is very important to improve the power system efficiency. Based on the previous basic studies, a thermal hydraulic prediction method for latent heat recovery exchangers was proposed. For the condensation of steam on heat transfer tubes, the modified Sherwood number taking account of the mass absorption effect on the wall was used. Two kinds of compact heat exchanger with staggered banks of bare tubes of 10.5 or 4mm in outer diameter was designed with the prediction method. The more compactness was obtained with the smaller tubes at a designed heat recovery. The thermal hydraulic behavior in the compact heat exchangers was experimentally studied with air-steam mixture gas. In the parametric experiments varying the steam mass concentration, the temperature distributions of cooling water and mixture gas were measured. The experimental results agreed well with the prediction proposed in this study and the more compactness with the smaller tubes was proved.

Download Full-text

Investigation of a Heat Pipe Heat Exchanger Integrated with a Water Spray for the Heat Recovery from Boil Exhaust Gas

Energy Procedia ◽

10.1016/j.egypro.2014.12.094 ◽

2014 ◽

Vol 61 ◽

pp. 2141-2144 ◽

Cited By ~ 4

Author(s):

Ye Yuan ◽

Yiji Lu ◽

Huashan Bao ◽

Yaodong Wang ◽

Wen Wang ◽

...

Keyword(s):

Heat Exchanger ◽

Heat Pipe ◽

Heat Recovery ◽

Exhaust Gas ◽

Water Spray ◽

Pipe Heat

Download Full-text

Investigation on the Influence of a Core Chevron Nozzle on the Performance of a Modern Bypass Engine

Volume 5: Turbo Expo 2004, Parts A and B ◽

10.1115/gt2004-53212 ◽

2004 ◽

Cited By ~ 2

Author(s):

Matthias Weißschuh ◽

Stephan Staudacher

Keyword(s):

Engine Performance ◽

Ambient Air ◽

Performance Comparison ◽

Turbine Engines ◽

Gas Streams ◽

Discharge Velocity ◽

Chevron Nozzle ◽

Nozzle Configuration ◽

Chevron Nozzles ◽

Considerable Work

In light of intensifying environmental concerns, the noise in aircraft gas turbine engines needs to be reduced significantly. Considerable work has been conducted to reduce jet noise produced by the mixing of high velocity gas streams with ambient air. Various nozzle designs such as lobed nozzles, serrated nozzles or chevron nozzles have been used and proposed to control and modify the velocity pattern of exhaust gas streams. This paper presents investigations on the influence of a core chevron nozzle on the performance of a modern bypass engine. The characteristic discharge, velocity and specific thrust coefficients of the chevron and non-chevron nozzles are determined by numerical calculations and are verified with experimental data. The nozzle coefficients form the basis for an engine performance comparison between the two hot nozzle configurations of the bypass engine. The effect of the nozzle configuration on overall engine performance and component working points has been investigated by applying an engine performance synthesis tool. The thrust loss and the corresponding SFC increase which has been observed by using the chevron nozzle have been related to engine internal rematching and changes in nozzle performance.

Download Full-text

Exergy Analysis of Natural Gas ICE-Based CHP System

ASME 2009 3rd International Conference on Energy Sustainability, Volume 2 ◽

10.1115/es2009-90013 ◽

2009 ◽

Cited By ~ 1

Author(s):

Xiling Zhao ◽

Lin Fu ◽

Shigang Zhang ◽

Jianzhang Zhu ◽

Baomin Huang ◽

...

Keyword(s):

Natural Gas ◽

Heat Recovery ◽

Waste Heat ◽

Operation Mode ◽

Mode I ◽

Mode Ii ◽

Exhaust Gas ◽

Liquid Desiccant ◽

Water Flows ◽

Recovery Unit

A challenge for CHP (Combined heating and power) system is the efficient integration of distributed generation (DG) equipment with thermally-activated (TA) technologies. Tsinghua University focuses on laboratory and demonstration research to study the critical issues of CHP systems, advance the technology and accelerate its application. The Research performed at the Building Energy Research Center (BERC) Laboratory focuses on assessing the operational performance and efficiency of the integration of current DG and TA technologies. The test system is composed of a 70-kW natural gas-fired internal combustion engine (ICE) with various heat recovery units, such as a flue gas-to-water heat recovery unit (FWRU), a jacket water heat recovery unit (JRU), liquid desiccant dehumidification systems (LDS), an exhaust-gas-driven double-effect absorption heat pump (EDAHP), and a condensation heat recovery unit (CRU)). In the winter, the exhaust gas from the ICE is used in the FWRU (operation mode I) or used to drive the EDAHP directly, and the exhaust gas from the EDAHP is used in the CRU (operation mode II). The water flows from the CRU can be directed to the evaporator side of the EDAHP as the lower-grade heat source. The water flows from the condensation side of the EDAHP, in conjunction with the jacket water flows from the JRU, is used for heating. In summer, the exhaust gas from the ICE is used to drive the EDAHP for cooling directly, and the waste heat of the jacket water is used to drive the liquid desiccant dehumidification systems, to realize the separate control of heat and humidity. In this paper, the exergy and energy analysis has been done on operation mode I and II according to the actual testing results, and it is show that the exergy efficiency of operation mode II is improved by 1.5% than operation mode I, and the energy efficiency of operation mode II is improved by 11% than operation mode I. The only way to improve the whole CHP is to maximize the use of the heat recovered by the ICE and to utilize the remaining heat of exhaust gas in other waste-heat driven equipments capable of using low grade waste heat like the CRU.

Download Full-text

Effects of the exhaust gas heat recovery system with a plate heat exchanger on the warm-up performance characteristics of the gasoline engine

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i2.12.11110 ◽

2018 ◽

Vol 7 (2.12) ◽

pp. 136

Author(s):

Chan JungKim ◽

Sank Wook-Han ◽

Ki Hyun Kim ◽

Moo Yeon Lee ◽

Gee Soo Lee

Keyword(s):

Heat Exchanger ◽

Fuel Economy ◽

Heat Recovery ◽

Exhaust System ◽

Plate Heat Exchanger ◽

Exhaust Gas ◽

Warm Up ◽

Plate Heat ◽

Recovery System ◽

Heat Recovery System

Background/Objectives: To meet the regulations for the fuel economy, an EHRS (Exhaust gas Heat Recovery System, which was installed within the vehicle exhaust system and recovered the heat from the exhaust gas, were needed. The EHRS enabled the engine to achieve the fast warm-up performance for reducing friction loss during the cold start.The objective of this paper was to investigate the effects of the design parameters of the EHRS with a plate heat exchanger on the warm-up performance of a gasoline engine.Methods/Statistical analysis: The EHRS with the plate heat exchanger was manufactured and installed behind the catalyst in the exhaust system of the gasoline direct injection engine. The experimental study and multi-disciplinary analysis were carried out to investigate the effects of the EHRS on the warm-up performance of the engine, such as the coolant temperature, the exhaust gas temperature and the recovery heat at idle condition and the step-load condition.Findings: Because the recovery of heat was about 1. 7 kW at idle condition, the effect of the EHRS on the warm-up performance was negligible. However, due to 17.2 kW of the recovery of heat at the stepload condition of T=140 Nm at N=2,400 rpm, the EHRS enabled to shorten the warm-up time by 548 s comparison that of the base engine.Improvements/Applications: The fuel economy will be expected to be improved through an EHRS, which provides the improved combustion in the warm-up phase and a decrease in friction loss.

Download Full-text

Comparative analysis of working fluids for efficient waste heat recovery

Journal of Physics Conference Series ◽

10.1088/1742-6596/2057/1/012102 ◽

2021 ◽

Vol 2057 (1) ◽

pp. 012102

Author(s):

D Ye Lola ◽

A Yu Chirkov ◽

Yu A Borisov

Keyword(s):

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Exhaust Gas ◽

Water Cooling ◽

Working Fluids ◽

Gas Recovery ◽

Recovery System

Abstract The paper analyzes the implementation of plants with an organic Rankine cycle (ORC) on the example of the circuit of the regenerative gas turbine unit and exhaust gas recovery system of the compressor system of the gas-compressor unit. The theoretically achievable values of power generated by the ORC-installations are determined. A criterion is presented for comparing the working fluids according to the efficiency of use in ORC-installations. To evaluate the overall characteristics of the system, the parameters of heat exchangers for air and water cooling were determined. As a result, it is concluded that the use of ORC-installations allows to utilize up to 23% of the heat of exhaust gases (convert into useful work).

Download Full-text

Different Configurations of Exhaust Gas Heat Recovery in Internal Combustion Engine: Evaluation on Different Driving Cycles Using Numerical Simulations

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4039304 ◽

2018 ◽

Vol 10 (4) ◽

Cited By ~ 1

Author(s):

Hanna Sara ◽

David Chalet ◽

Mickaël Cormerais

Keyword(s):

Numerical Simulations ◽

Fuel Consumption ◽

Heat Recovery ◽

Combustion Engine ◽

Management Strategies ◽

Driving Cycle ◽

Maximum Temperature ◽

Exhaust Gas ◽

Direct Heating ◽

Driving Cycles

Exhaust gas heat recovery is one of the interesting thermal management strategies that aim to improve the cold start of the engine and thus reduce its fuel consumption. In this work, an overview of the heat exchanger used as well as the experimental setup and the different tests will be presented first. Then numerical simulations were run to assess and valorize the exhaust gas heat recovery strategy. The application was divided into three parts: an indirect heating of the oil with the coolant as a medium fluid, a direct heating of the oil, and direct heating of the oil and the coolant. Different ideas were tested over five different driving cycles: New European driving cycle (NEDC), worldwide harmonized light duty driving test cycle (WLTC), common Artemis driving cycle (CADC) (urban and highway), and one in-house developed cycle. The simulations were performed over two ambient temperatures. Different configurations were proposed to control the engine's lubricant maximum temperature. Results concerning the temperature profiles as well as the assessment of fuel consumption were stated for each case.

Download Full-text