Development of Plate-Type Heat Exchanger for Exhaust Gas Heat Recovery System

2003 ◽  
Author(s):  
Hyunjae Park ◽  
Anthony Bowman ◽  
Tod Stansfield ◽  
Brian Huibregtse

In this paper, an exhaust gas heat recuperation unit for use with a boiler is developed to improve the overall thermal efficiency of integral system. The heat recuperation unit includes a plate-type heat exchanger for exhaust gas heat recovery for exchanging heat between an exhaust gas and combustion air. A proto-type heat exchanger is designed and manufactured with a series of exhaust gas plates stacked alternatively with, and parallel to, a series of air plates. Each of the exhaust gas plates and air plates contain ridges to form a substantially sinusoidal path for directing the respective gas therealong. The combustion air flown in a countercurrent to the exhaust gas to facilitate maximum heat transfer. The heat exchanger is connected to exhaust gas inlet and outlet conduits and combustion air inlet and outlet conduits. Proper number of plates for the heat exchanger is selected to obtain laminar flow through plate flow channels, producing a low gas pressure drop in each channel. Using the proto-type heat exchanger, experimental work was primarily performed to measure temperature and pressure changes of exhaust gas and combustion air at various boiler firing conditions. These test results are compared with those obtained from numerical (CFD) and analytical works. The approximate analytical model developed in this work is used to investigate the effects of exchanger design parameters on the system performance, and eventually to develop the exchanger design curves for the optimal selection of exchanger design values.

2012 ◽  
Author(s):  
Sharifah Rafidah Wan Alwi ◽  
Muhammad Azan Tamar Jaya ◽  
Zainuddin Abdul Manan

Kilang penapisan minyak sawit lazimnya melibatkan proses penggunaan tenaga yang tinggi. Peningkatan kecekapan tenaga adalah amat penting bagi memastikan keuntungan tercapai. Kertas kerja ini menggunakan teknik analisis jepit bagi memaksimumkan penggunaan semula haba dan meningkatkan kecekapan sistem rangkaian haba sedia ada di kilang penghasilan minyak sawit, tertakluk kepada kekangan–kekangan proses. Langkah–langkah yang terlibat ialah penetapan sasaran guna semula haba maksimum diikuti dengan reka bentuk rangkaian haba yang ekonomik. Aplikasi teknik berkenaan kepada kilang penghasilan minyak sawit telah menghasilkan pengurangan penggunaan haba panas dan sejuk sebanyak 700 kW (21%), atau penjimatan kos utiliti sebanyak RM370,787, dengan pelaburan kapital sebanyak RM656,293 dan jangka pulangan balik selama 1.77 tahun. Kata kunci: Analisis jepit; minyak kelapa sawit; sedia ada; rangkaian pemindahan haba; kitar semula haba maksimum A palm oil refinery involves energy–intensive processes. Maximizing thermal efficiency of palm oil refinery is crucial for the plant profitability. This work implements a pinch analysis retrofit technique to maximize heat recovery and thermal efficiency of a palm oil refinery, subject to the existing process constraints. The procedures involve setting the maximum heat recovery targets and cost–effective retrofit of the heat exchanger network (HEN). Application of the technique on a palm oil refinery results in reduction of 700 kW (21%) heating and cooling loads or a saving of RM370,787, incurring a capital investment of about RM656,293 and a payback period of 1.77 years. Key words: Pinch analysis; palm oil; retrofit; heat exchanger network; maximum heat recovery


Author(s):  
Masahiro Osakabe

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.


2013 ◽  
Vol 21 (02) ◽  
pp. 1350009 ◽  
Author(s):  
HWATAIK HAN ◽  
SANG-HOON NAM ◽  
GEON-SOO HAN

This study experimentally investigates the effect of internal condensation on the performance of a heat recovery ventilator. Experiments were performed using a plate-type sensible heat exchanger element that was designed for very humid and dusty environments such as chicken broiler houses. The results of these experiments show that the temperature efficiency considering condensation is always greater than that without considering latent heat. As outdoor temperature decreases or indoor relative humidity increases, temperature efficiency increases owing to an increase in the rate of condensation. The present polypropylene-based sensible heat exchanger element could be a solution for harsh environments because it can discharge condensate water by gravity and is resistant to moisture and other toxic gases.


2014 ◽  
Vol 61 ◽  
pp. 2141-2144 ◽  
Author(s):  
Ye Yuan ◽  
Yiji Lu ◽  
Huashan Bao ◽  
Yaodong Wang ◽  
Wen Wang ◽  
...  

2018 ◽  
Vol 7 (2.12) ◽  
pp. 136
Author(s):  
Chan JungKim ◽  
Sank Wook-Han ◽  
Ki Hyun Kim ◽  
Moo Yeon Lee ◽  
Gee Soo Lee

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.  


2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Amnart Boonloi ◽  
Withada Jedsadaratanachai

Numerical assessments in the square channel heat exchanger installed with various parameters of V-orifices are presented. The V-orifice is installed in the heat exchanger channel with gap spacing between the upper-lower edges of the orifice and the channel wall. The purposes of the design are to reduce the pressure loss, increase the vortex strength, and increase the turbulent mixing of the flow. The influence of the blockage ratio and V-orifice arrangement is investigated. The blockage ratio, b/H, of the V-orifice is varied in the range 0.05–0.30. The V-tip of the V-orifice pointing downstream (V-downstream) is compared with the V-tip pointing upstream (V-upstream) by both flow and heat transfer. The numerical results are reported in terms of flow visualization and heat transfer pattern in the test section. The thermal performance assessments in terms of Nusselt number, friction factor, and thermal enhancement factor are also concluded. The numerical results reveal that the maximum heat transfer enhancement is found to be around 26.13 times higher than the smooth channel, while the optimum TEF is around 3.2. The suggested gap spacing for the present configuration of the V-orifice channel is around 5–10%.


2013 ◽  
Vol 21 (01) ◽  
pp. 1350002 ◽  
Author(s):  
YOUNES KARTACHI ◽  
ABDELLAH MECHAQRANE

In this study, we analyze the impact of ventilation heat recovery with the heating and cooling potential of earth air heat exchanger in real climatic conditions in domestic buildings in the Middle Atlas region. In our case study, we calculate the primary energy used by a domestic building built as per the conventional house design parameters required by the Moroccan regulation. We use climate data for the city of Fes in Northern Moroccan. Three system configurations were considered. The first was the mechanical extract ventilation system both with and without heat recovery. The second was the mechanical extract ventilation system with earth to air heat exchanger system (EAHEX), and the third system was the mechanical balanced ventilation system coupled with EAHEX system. Primary energy use strongly influences natural resources efficiency and the environmental impacts of energy supply activities. In this study we explore the primary energy implications of the mechanical balanced ventilation system coupled with the EAHEX system in residential buildings. The results of this study shows that the use of a balanced ventilation system, with a high efficiency instead of a mechanical extract ventilation system, decreases the final and primary energy consumption. Moreover, it decreases or increases the CO2 emission depending on the primary energy sources.


1991 ◽  
Vol 113 (3) ◽  
pp. 294-300 ◽  
Author(s):  
Ching Jen Chen ◽  
Ramiro H. Bravo

In this study, fluid flow and heat transfer in two-dimensional staggered thin rectangular blocks in a channel flow heat exchanger is analyzed by the Finite Analytic Numerical Method. The heat exchanger consists of four staggered thin rectangular blocks at temperature T1 placed inside a channel which is formed by two plates maintained at constant temperature T0. The fluid is considered to be incompressible and the flow laminar. Flow and heat transfer from the inlet of the heat exchanger to the outlet are simulated by solving Navier-Stokes and energy equations. Results were obtained for different block spacing and different size of the blocks. Computations were made for Reynolds numbers 100, 500, and 1,000, and Prandtl numbers 0.7 and 4.0. The results are presented in the form of velocity vector fields, isotherms, and local and global Nusselt numbers. The characteristics of the heat transfer and pressure drop in different block size and block separation are analyzed. The optimal length of separation between thin blocks and the optimal block length for maximum heat transfer are determined.


2019 ◽  
Vol 25 (8) ◽  
pp. 39-51
Author(s):  
Nassr Fadhil Hussein ◽  
Abdulrahman Shakir Mahmood

Enhancement of heat transfer in the tube heat exchanger is studied experimentally by using discrete twisted tapes. Three different positions were selected for inserting turbulators along tube section (horizontal position by α= 00, inclined position by α= 45 0 and vertical position by α= 900). The space between turbulators was fixed by distributing 5 pieces of these turbulators with pitch ratio    PR = (0.44). Also, the factor of constant heat flux was applied as a boundary condition around the tube test section for all experiments of this investigation, while the flow rates were selected as a variable factor (Reynolds number values vary from 5000 to 15000). The results show that using discrete twisted tapes enhances the heat transfer rate by about 60.7-103.7 % compared with plane tube case. Also, inserting turbulators with inclined position offers maximum heat transfer rate by 103.7%.  


Author(s):  
Zhihang Chen ◽  
Colin Copeland ◽  
Bob Ceen ◽  
Simon Jones ◽  
Alan Agurto Goya

The exhaust gas from an internal combustion engine contains approximately 30% of the thermal energy of combustion. The exhaust-gas heat-recovery systems aim to reclaim a proportion of this energy in a bottoming thermodynamic cycle to raise the overall system thermal efficiency. The inverted Brayton cycle (IBC) considered as a potential exhaust-gas heat-recovery system is a little-studied approach, especially when applied to small automotive power-plants. Hence, a model of the inverted Brayton cycle using finite-time thermodynamics (FTT) is presented to study heat recovery applied to a highly downsizing automotive internal combustion engine. IBC system consists of a turbine, a heat exchanger (HE), and compressors in sequence. The use of IBC turbine is to fully expand the exhaust gas available from the upper cycle. The remaining heat in the exhaust after expansion is rejected by the downstream heat exchanger. Then, the cooled exhaust gases are compressed back up to the ambient pressure by one or more compressors. In this paper, the exhaust conditions available from the engine test bench data were introduced as the inlet conditions of the IBC thermodynamic model to quantify the power recovered by IBC, thereby revealing the benefits of IBC to this particular engine. It should be noted that the test bench data of the baseline engine were collected by the worldwide harmonized light vehicles test procedures (WLTP). WLTP define a global harmonized standard for determining the levels of pollutants and CO2 emissions, fuel consumption. The IBC thermodynamic model was simulated with the following variables: IBC inlet pressure, turbine pressure ratio, heat exchanger effectiveness, turbomachinery efficiencies, and the IBC compression stage. The aim of this paper is to analysis the performance of IBC system when it is applied to a light-duty automotive engine operating in a real-world driving cycle.


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