scholarly journals Fireside Corrosion on Heat Exchanger Surfaces and Its Effect on the Performance of Gas-Fired Instantaneous Water Heaters

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2583
Author(s):  
Xiaomei Huang ◽  
Mengxiao Sun ◽  
Yinhu Kang
Keyword(s):  
Heat Exchanger ◽  
Corrosion Product ◽  
Heat Input ◽  
Heat Exchangers ◽  
Test Duration ◽  
Water Heater ◽  
Fireside Corrosion ◽  
Water Heaters ◽  
Corrosion Deposits ◽  
Corrosion Deposit

The heat exchanger in a gas instantaneous water heater is a thermal device used for heat transfer from the high-temperature flue gas to the low-temperature water. The fireside corrosion, due to the reaction of acidic condensate formed on the heat exchanger surfaces and its metallic material, is one of the major hazards for gas instantaneous water heaters. This paper focuses on identifying and quantifying the fireside corrosion on the surface of heat exchangers in gas-fired instantaneous water heaters. Durability tests lasting for 2000 cycles were undertaken for five gas-fired instantaneous water heaters, which were different in terms of the heat input and coating of heat exchangers. The corrosion deposits on the surface of the heat exchangers were surveyed by several methods. The results show that the corrosion deposit grew as the test duration increased. The fins of the heat exchanger with a lead coating had been corroded and copper was exposed. Cu4(OH)6SO4 was the main corrosion product of heat exchangers without a lead coating, whereas PbSO4 was the main corrosion product of heat exchangers with a lead coating. The experiments demonstrate that the corrosion rate decreased with the increase of the heat input. The experiments also show that the thermal efficiency of gas instantaneous water heaters decreased by 2.4% to 6% at the end of the test duration.

Thermal Properties Study of a Solar Water Heater Tank with a Mantle Exchanger

2014 ◽  
Vol 3 (1) ◽  
pp. 92-100 ◽  
Author(s):  
Mourad Chikhi ◽  
Rabah Sellami ◽  
Nachida Kasbadji Merzouk
Keyword(s):  
Heat Exchanger ◽  
Renewable Energy Sources ◽  
Supply And Demand ◽  
Research Work ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Incentive Programs ◽  
Water Heaters ◽  
Solar Water Heaters

The development and use of renewable energy sources and technologies are becoming vital for the management of energy supply and demand. For development solar water heaters, the incentive programs are supported by the Algerian government to generalize the using of this kind of energy especially in Sahara. This study is a part of program to develop a new solar water heater in UDES (Algeria). In this research work, the thermal performance of a solar water heater with a mantle heat exchanger is investigated numerically using Comsol Multyphysics software. The objective is to investigate the influence of the mantle heat exchanger thickness on the performance of solar water heaters. The results show, for 160 liters capacity of the solar water heaters tank, the 13mm of the heat exchanger thickness leads to improve the efficiency of the solar water heater.

Performance and Modeling of Thermosyphon Heat Exchangers for Solar Water Heaters

1997 ◽  
Vol 119 (3) ◽  
pp. 193-200 ◽  
Author(s):  
S. D. Dahl ◽  
J. H. Davidson
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Heating Systems ◽  
Solar Water ◽  
Water Heaters ◽  
Prandtl Numbers ◽  
Area Product ◽  
Solar Water Heaters

Determining the performance of indirect solar heating systems that use thermosyphon heat exchangers requires knowledge of how thermosyphon flow rate and heat exchanger performance vary with operating conditions. In this paper, measured performance of a two-pass, tube-in-shell, double-wall heat exchanger is discussed in terms of modeling issues. Thermosyphon heat exchangers may operate in the developing, mixed convection regime where natural convection effects can significantly influence overall heat transfer and friction coefficients. Existing models which assume the thermal and hydraulic behaviors of thermosyphon heat exchangers are only functions of the thermosyphon and collector flow rates may not be suitable for all heat exchanger types. For example, the overall heat-transfer coefficient-area product for the two-pass, tube-in-shell heat exchanger is best expressed as a function of Reynolds, Grashof, and Prandtl numbers on the thermosyphon side of the heat exchanger. It is proposed that annual simulations of solar water heaters with thermosyphon heat exchangers use this type of relationship to characterize heat transfer in the heat exchanger.

Effect of Surface Roughness and Micro-Grooves on Condensed Water Removal in Latent Heat Recovery Heat Exchanger

2011 ◽  
Author(s):  
Kenta Kimoto ◽  
Hitoshi Asano ◽  
Masafumi Sakurai ◽  
Tetsuro Hamada ◽  
Makoto Hirotsu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Latent Heat ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Horizontal Tube ◽  
Hot Water ◽  
Water Heater ◽  
Water Heaters ◽  
Condensed Water

Hot-water supply has high percentage of energy consumption in Japanese civilian sector. Gas water heaters are used in most cases. Therefore, improvement in thermal efficiency of a gas water heater is an important issue for energy saving. In order to improve thermal efficiency of a gas water heater, an additional heat exchanger is required for latent heat recovery from exhaust humid combustion. The purpose of this study is to develop a compact latent heat recovery heat exchanger with a simple configuration. It is necessary for compactness to reduce the gap between the heat transfer tubes. However, the narrow gap will cause stagnation of condensed water. In order to remove the condensed water from horizontal tube bank, three kinds of tubes with different surface treatments, polished tubes, unpolished tube, and smooth tube with circular micro-grooves, were examined. As the result, condensed water was easily removed by the groove with the 0.7mm depth, to avoid the formation of water bridges between tubes. The effect could lead to no deterioration in the heat transfer performance by decreasing the tube clearance to 1.0mm.

scholarly journals Experimental Study of the Efficiency of a Solar Water Heater Construction from Recycled Plastic Bottles

2021 ◽  
Vol 16 (2) ◽  
pp. 121-126
Author(s):  
Besma Chekchek ◽  
Mohamed Salmi ◽  
Abdelhakim Boursas ◽  
Giulio Lorenzini ◽  
Hijaz Ahmad ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Water Temperature ◽  
Heat Exchangers ◽  
Polymeric Materials ◽  
Solar Water Heater ◽  
Water Heater ◽  
Conservation Of Energy ◽  
Flow Rates ◽  
Primary Materials

A solar polymer heat exchanger is designed to heat water; its primary materials are plastic water bottles with a capacity of 1.5 liters. These materials were recycled to preserve the environment and to make use of it again. The thermal insulation properties are adopted for the characterization of polymeric materials. These properties concern the conservation of energy for the longest period of time and the absence of problems caused by rust and corrosion, which are usually encountered in traditional heat exchangers. The heat exchanger experiments start by tracking the flow of water inside the pipes by a valve. The water temperature and flow rates are determined at the inlet and outlet surfaces of the exchanger. The obtained results indicated an increase in water temperature exceeding 10℃ in an ideal spring day. The thermal efficiency of the solar collector was about 62% under the sunlight, and 44% in the laboratory where halogen lamps were used as an industrial light source.

Modeling and Optimization of Heat Exchangers Within Gas Turbine Systems

2012 ◽  
Author(s):  
Georgiana Tirca-Dragomirescu ◽  
Monica Costea ◽  
Michel Feidt ◽  
Jim McGovern ◽  
Alexandru Dobrovicescu ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Combustion Chamber ◽  
Detailed Analysis ◽  
Gas Turbine ◽  
Heat Exchangers ◽  
Operating Regime ◽  
The Other ◽  
Perfect Gas ◽  
Water Heater ◽  
Heating Water

The paper presents an analysis of a recuperative gas turbine system used for micro-cogeneration based on energetic and exergetic principles. The system is composed of two compressors (one for the fuel, the other for air), a combustion chamber, a gas turbine, a recuperator used to preheat the air before entering the combustion chamber and a heat exchanger for heating water. The analysis compares three different configurations obtained by placing the recuperator upstream of, downstream of, or in parallel with the water heater. It is subject to the following assumptions: the fuel is injected steadily and ideally (without irreversibility), the air is a perfect gas, the heat exchangers are adiabatically isolated from the surroundings and the compressors and the turbine are adiabatic. A detailed analysis of the thermal and mechanical irreversibilities of the cycle is also presented. The optimization goal is to minimize the entropy generation or to maximize the useful exergy output of the system. With this approach the best configuration for a specified operating regime of micro-cogeneration can be determined.

scholarly journals Residential Drain Water Heat Recovery Systems: Modeling, Analysis, and Implementation

2010 ◽  
Vol 5 (3) ◽  
pp. 85-94 ◽  
Author(s):  
Scott Bartkowiak ◽  
Ryan Fisk ◽  
Andrew Funk ◽  
Jonathan Hair ◽  
Steven J Skerlos
Keyword(s):  
Heat Exchanger ◽  
Natural Gas ◽  
Flat Plate ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Cold Water ◽  
Hot Water ◽  
Published Data ◽  
Drain Water ◽  
Water Heaters

This paper describes the design and environmental improvements that can be achieved using drain water heat recovery systems (DWHR) to reduce the energy consumption associated with residential showering. DWHR systems transfer heat from hot drain water to the shower's incoming cold water stream, thus reducing the demand on the hot water heater. There are various DWHR systems available that differ in heat exchanger type, cost, and performance. This article focuses on designing a flat plate and gravity fed heat exchangers for a range of residential showering conditions. This is useful since there currently is no peer-reviewed published data on the effectiveness of DWHR, nor is there published research considering the emissions reductions that can be achieved with realistic DWHR systems. The governing equations for heat exchangers are used to model empirical data and to derive implementation recommendations for DWHR design. The model is validated using a prototype flat plate heat exchanger and test stand under varying flow rates and temperatures. A Monte Carlo simulation of the results showed that DWHR could save an average $74 a year for homes with natural gas water heaters and $160 a year for homes with electric water heaters. This corresponds to 0.3 metric tons and 1.5 metric tons of CO2offset per home per year for natural gas and electric water heaters, respectively. The results are compiled and organized into a software program that allows consumers to input their household showering habits and location to get an estimate of their CO2, energy, and cost savings to determine if they should install a DWHR system.

scholarly journals A New Approach for Characterizing Pile Heat Exchangers Using Thermal Response Tests

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3375
Author(s):  
Charles Maragna ◽  
Fleur Loveridge
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Thermal Response ◽  
Cost Effective ◽  
Thermal Capacity ◽  
Study Data ◽  
Design Parameters ◽  
Test Duration ◽  
Ground Source

Pile heat exchangers offer a cost effective route to implementation of ground-source heat pump systems for many large commercial buildings compared with traditional boreholes. Such projects typically use thermal response tests to determine the key input parameters for system design, namely soil thermal conductivity and heat exchanger thermal resistance. However, this brings challenges for pile heat exchanger based systems, where in situ thermal response tests are known to be less reliable due to the large thermal capacity of the pile. This paper presents a new “black box” resistance capacitive model for applications to pile thermal response tests. The approach is tested against case study data and shown to perform well. Additional test duration savings are shown to be possible if a novel combination of borehole and pile thermal response tests is applied together to determine design parameters.

REVERE No. 508

Alloy Digest ◽  
1959 ◽  
Vol 8 (9) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Heat Exchanger ◽  
Physical Properties ◽  
Nickel Alloy ◽  
Salt Water ◽  
Heat Treating ◽  
Feed Water ◽  
Water Heater ◽  
Corrosion Resistant ◽  
Copper Nickel Alloy

Abstract Revere No. 508 is a highly ductile, malleable and corrosion resistant copper-nickel alloy suitable for condenser and heat exchanger tubes and many engineering applications such as salt water piping aboard ship, many components of salt water and fresh water stills, feed water heater tubes and marine coolers. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-81. Producer or source: Revere Copper and Brass Inc..

MUELLER ALLOY 7060

Alloy Digest ◽  
1985 ◽  
Vol 34 (10) ◽  
Keyword(s):  
Heat Exchangers ◽  
Cold Working ◽  
Elevated Temperatures ◽  
Salt Water ◽  
Iron Alloy ◽  
Heat Treating ◽  
Good Resistance ◽  
Nickel Iron ◽  
Water Heaters ◽  
Nickel Iron Alloy

Abstract MUELLER Alloy 7060 is a copper-nickel-iron alloy. It has good strength at moderately elevated temperatures and can be fabricated by both hot and cold-working procedures. It contains nominally 11/4 iron to increase its resistance to corrosion and erosion. It has good resistance to corrosion by salt water and is used in marine service. It is used widely for condenser tubes, distiller tubes, heat exchangers, evaporators and water heaters for domestic service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-501. Producer or source: Mueller Brass Company.

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