• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.6
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• pp.441-448
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• 2011

The energy consumption of a condensing gas boiler may be greatly reduced by the effective operation of the unit. In this study, the supply water algorithm for a condensing gas boiler control was developed by using the fuzzy logic. This includes the supply water set temperature algorithm, and the control algorithms of a gas valve, a blower and a pump. For the set temperature algorithm, the outside air temperature and the return water temperature were used as input variables. The supply water temperature difference and its slope were used as input variables of the gas valve and blower control algorithm. And the supply water temperature and the return water temperature were used as input variables of the pump control algorithm. In order to analyse performances of these algorithms, the dynamic model of a condensing gas boiler was used. The initial start-up test, the supply water set temperature change test, the outside air temperature change test, and the return water temperature change test were performed. Simulation results showed that algorithms developed in this study may be practically applied for the effective control of a condensing gas boiler.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.111-112
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• 2014

Exhaust gas boiler system with respect to national and international safety standards, comparative study best suited to the realities of local exhaust and exhaust system manufacturing, certification standards and gas boiler installation, management, and mip draft inspection standards will proceed through this study.

• Journal of the Korean Society of Combustion
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• v.15 no.1
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• pp.43-49
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• 2010

Co-combustion of syngas in an existing boiler can be one of the options for replacing conventional fossil fuel with alternative fuels such as waste and biomass. This study is aimed to investigate effects of syngas cocombustion on combustion characteristics and boiler efficiency. An experimental study was performed for a pilot-scale furnace with 4 oil burners. Tests were conducted with mixture-gas as a co-combustion fuel and heavy oil as a main fuel. The mixture-gas was composed of 15% CO, 7% $H_2$, 3% $CH_4$ and 75% $N_2$ for simulating syngas from air-blown gasification. And LHV of the mixture-gas was 890 kcal/$Nm^3$. Temperature distribution in the furnace and flue gas composition were measured for various heat replacement ratio by the mixture gas. Heat loss through the wall was also carried out through heat & mass balance calculation, in order to obtain informations related to boiler efficiency. Experimental results show that similar temperature distribution and flue gas composition can be obtained for the range of 0~20% heat replacement by syngas. NOx concentration is slightly decreased for higher heat replacement by the syngas because fuel NOx is decreased in the case. Meanwhile, heat loss is a bit decreased for higher heat replacement by the syngas, which implies that boiler efficiency can be a bit decreased when syngas co-combustion is applied to a boiler.

• Journal of Energy Engineering
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• v.20 no.4
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• pp.330-337
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• 2011

In these days, the gas or kerosene boiler was usually used as heating system. This study was carried out to investigate the merits of X-L pipe boiler with electric heat line that was specially manufactured. The electric heat line was inserted into inside of X-L pipe and voltage was impressed to electric heat line and, as a result, temperature of X-L pipe filled with heat medium was increased. As changing the number of electric heat line and voltage, the characteristics of X-L pipe boiler and its mechanism on heat generation were studied. Furthermore, the economical efficiency was evaluated by comparing heating cost of X-L pipe boiler with those of kerosene boiler and natural gas boiler, respectively. As the results, it was confirmed that heating cost of X-L pipe boiler was showed as 28% of kerosene boiler and 58% of natural gas boiler.

• Korean Journal of Human Ecology
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• v.20 no.6
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• pp.1153-1165
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• 2011

Decision making for gas boiler consumers depends on the characteristics of products such as the price and quality as well as the brand image. Although a gas boiler is a high involvement product in terms of price, in fact, it is a low involvement product which is greatly affected by installers. This study examined variables which affect the level of satisfaction and repurchase intention by surveying about 1,000 housewives through an on-line questionnaire. The results were as follows: first, gas boiler users' general knowledge of gas boilers showed a correct-answer rate of 54.5%. The average satisfaction score of product quality (mean=5.61 out of 7) was higher than that of the satisfactionscore of the company's service (mean=5.46). Second, the level of repurchase intention was above the mid-point (mean=4.72). Multivariate regression found that product satisfaction, service satisfaction, household size, and information sources explained repurchase intentions for gas boilers to be about 50.7%. Gas boiler marketers should pay attention to the survey result in that the level of repurchase intention depends mainly on both consumer satisfaction and information sources.

• Korean Journal of Hazardous Materials
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• v.6 no.2
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• pp.77-86
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• 2018

Interest in renewable energy is increasing for eco-friendly use of energy, and fuel cells are being used in various ways such as houses and buildings as power generation methods that have low emissions such as $NO_X$ and $CO_2$. As the supply of fuel cells expands, more and more boilers are installed in the existing buildings, but safety management is not being performed properly. Therefore, in this study, a prior study was conducted on the status of fuel cell-boiler complex installation and related criteria, and the risk factors were analyzed according to the installation environment and structure. Based on these standards, the safety performance of the fuel cell-boiler combined installation is assessed by conducting a demonstration using the starting product of the simulated operation to derive the installation criteria (proposal) for the fuel cell-boiler combined installation. The installation criteria (proposal) include the construction and connection method of the piping according to the fuel cell-boiler complex installation.

• Journal of Internet of Things and Convergence
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• v.8 no.1
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• pp.23-29
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• 2022

The product to be developed in this study is a heat recovery device which generates steam or hot water at high temperature and high pressure by heating water using exhaust gas from diesel engine, gas engine, gas turbine, etc. as an exhaust gas boiler off heat boiler(EGB) type for ship and power generation. The steam vapor or the created warm water is used as the power source required for the steerage heating and hot water facility or the HFO heating of the ship, and the turbine drive. The principle of waste heat boilers serves to heat water as high temperature exhaust gas with heat pass through the tube of the boiler. The heated water is a structure that is sent to a cabin or turbine device in the form of steam. In this study, the objective of this study is to maximize the efficiency by increasing the heat transfer surface by replacing the tube which is the heat transfer part of EGB with the plate tube.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.04a
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• pp.201-207
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• 2000

This study was carried out to optimize burner and heat exchanger of the condensing gas boiler which can save energy by utilizing latent heat of combustion gas and reduce pollutant in exhaust gas. The heat exchanger of the gas boiler was composed of three parts, which were an upper. lower , and coil heat exchanger . The upper heat exchanger was placed outside of the premixed burner and a lower heat exchanger was located under the upper heat exchanger. And, coil heat exchanger rounded the outer surface of an upper and lower heat exchanger. The boiler designed by this research reaches turn-down ratio 4 : 1 in the domain of equivalence ratio 0.75-0.8 and thermal efficiency of 97% . Emission of NOx and CO concentration was under 20ppm and 140ppm at equivalence ratio 0.8 . When diameter of the burner replace 60mm by 50mm. emission of CO was reduced about 50ppm remarkably.

• Plant Journal
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• v.4 no.3
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• pp.54-59
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• 2008

The resonance of boiler is caused by exciting force in the gas path and it generates the vibration by the harmony of boiler's dimensional factor. According to trending toward the boiler of increasing capacity and a bigger size, it has a problem of the vibration at back-pass heating surfaces. We can predict such vibrations as comparison between vortex frequency and gas column's natural frequency. We can't rely on the method for the past decades because of changing parameters, such as an allowable error, gas temperature, gas velocity, Strouhal number. We can reduce the vibration to use the seasoning effect and change the operating condition in coal fired boiler but it's not essential solution. When the vibration occurred in the model boiler, we must measures the acoustic pressure and frequency of places for considering the means. So far, we confirmed the problem from field measures and theoretical analysis about the acoustic vibration of boiler. We installed anti-acoustic baffle in a existing boiler to change the acoustic natural frequency at the cavity, which results in reducing the acoustic vibration. The first, we prove that the acoustic resonance is caused by harmonizing vortex shedding frequency of tube heat surface with acoustic natural frequency of cavity in the range of 650~750 MW loads. The second, the acoustic resonance at the back-pass heating surface has the third order of acoustic natural frequency at the second economizer. We install five anti-acoustic baffles at the second economizer to reducing the resonance. We confirm considerably reducing the acoustic vibration of boiler during the commercial boiler.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.2
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• pp.244-251
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• 2001

This paper describes a design study of heat exchanger assembly to be used for low NOx condensing gas boiler. In this study, specifications of each heat exchanger components(upper and lower fin-type HEX, coil-type HEX, baffle) were investigated experimently by using model apparatus and analytical model, and comprehensive performances of the pilot gas boiler were examined. As a result, the boiler efficiency for heating and hot-water reached 90% and 94%, respectively. NOx and CO emission are less than 50ppm and 200ppm (0$_2$0% basis), respectively, which are very improved results than those of conventional bunsen-type boiler. But it is considered that supplementary investigations necessary for CO emission improvement and optimum design with boiler capacity.