• Journal of Energy Engineering
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• v.28 no.3
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• pp.65-79
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• 2019

The study attempted to estimate the optimal facility capacity by combining renewable energy sources that can be connected with gas CHP in industrial complexes. In particular, we reviewed industrial complexes subject to energy use plan from 2013 to 2016. Although the regional designation was excluded, Sejong industrial complex, which has a fuel usage of 38 thousand TOE annually and a high heat density of $92.6Gcal/km^2{\cdot}h$, was selected for research. And we analyzed the optimal operation model of CHP Hybrid System linking fuel cell and photovoltaic power generation using HOMER Pro, a renewable energy hybrid system economic analysis program. In addition, in order to improve the reliability of the research by analyzing not only the heat demand but also the heat demand patterns for the dominant sectors in the thermal energy, the main supply energy source of CHP, the economic benefits were added to compare the relative benefits. As a result, the total indirect heat demand of Sejong industrial complex under construction was 378,282 Gcal per year, of which paper industry accounted for 77.7%, which is 293,754 Gcal per year. For the entire industrial complex indirect heat demand, a single CHP has an optimal capacity of 30,000 kW. In this case, CHP shares 275,707 Gcal and 72.8% of heat production, while peak load boiler PLB shares 103,240 Gcal and 27.2%. In the CHP, fuel cell, and photovoltaic combinations, the optimum capacity is 30,000 kW, 5,000 kW, and 1,980 kW, respectively. At this time, CHP shared 275,940 Gcal, 72.8%, fuel cell 12,390 Gcal, 3.3%, and PLB 90,620 Gcal, 23.9%. The CHP capacity was not reduced because an uneconomical alternative was found that required excessive operation of the PLB for insufficient heat production resulting from the CHP capacity reduction. On the other hand, in terms of indirect heat demand for the paper industry, which is the dominant industry, the optimal capacity of CHP, fuel cell, and photovoltaic combination is 25,000 kW, 5,000 kW, and 2,000 kW. The heat production was analyzed to be CHP 225,053 Gcal, 76.5%, fuel cell 11,215 Gcal, 3.8%, PLB 58,012 Gcal, 19.7%. However, the economic analysis results of the current electricity market and gas market confirm that the return on investment is impossible. However, we confirmed that the CHP Hybrid System, which combines CHP, fuel cell, and solar power, can improve management conditions of about KRW 9.3 billion annually for a single CHP system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.5
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• pp.321-326
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• 2008

This paper presents and analyzes the effects of on-grid electricity cost, fuel price and initial capital cost of a CHP system, on the optimum DG and AC capacity and NPV, by using the ORNL CHP Capacity Optimizer, which was applied to a library in a university. By considering the current domestic energy cost and initial capital cost, it is shown that the installation and operation of the CHP system is not economical. However, with the current domestic CHP installation cost and fuel price, the NPV achieved by the installation of CHP system is greater when the on-grid electricity price is a factor of ${\times}1.5$ the present value. Regarding the initial capital cost of the CHP system, the reduction of the DG cost is much more economical than that of the AC cost, with respect to NPV. Electricity cost and fuel price have opposite effects on NPV, and NPV is more sensitive to an increase of the electricity cost than an increase of the fuel price.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.2
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• pp.97-103
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• 2004

CHP system supplies electricity and heating together with high efficiency. Current utility's CHP system uses electric power by itself and sells thermal energy to KDHC(Korea District Heating Corporation). CHP's operation cost except sales revenue of heating was covered by the sale revenue of electricity. Thus Electric generation cost in district Heating CHP system has close relationship with the level of heating price. However, after the restructuring of electricity industry, the operation cost could not be covered by sales revenue of heating and electricity. This loss was compensated by energy subsidy program in the electric power industry infrastructure fund. This paper suggests reasonable evaluation and improvement methods of the loss calculation of CHP system utilizing the infrastructure fund efficiency In terms of the direction of support by the fund, it provides the methods to prevent inefficient operation through setting up the upper limit of subsidy and to improve the loss calculation. Moreover, it suggest fixed rate support by heating supply level and reducing subsidy gradually for an efficient operation of CHP system.

• Polymer(Korea)
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• v.24 no.2
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• pp.252-258
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• 2000

Various crosslinked poly(4-vinylpyridines) (CHP4VP) having different degrees of crosslinking were synthesized by radical copolymerization of 4-vinylpyridine with if N,N' -1, 6-hexamethylenebisacrylamide, and CHP4VP- Cu(II) complexes were prepared by the method of adsorption equilibrium. The catalytic activity of the complexes for the oxidation of ascorbic acid (AA) was investigated. The oxidation of AA by these complexes showed a kinetic behavior of the Michaelis-Menten type. The catalytic activity of CHP4VP-Cu(I ) catalytic system was increased with increasing the degree of crosslinking of CHP4VP, and its activity was scarcely decreased even after repeated use. However, the tendency of the catalytic activity of CHP4VP-Cu(II) complexes was decreased for the oxidation of AA when compared with that of the previously reported catalytic system containing crosslinked poly(4-vinylpyridine) prepared using N,N'-methylenebisacrylamide as a crosslinker. These results indicate that the degree of crosslinking of CHP4VP and the hydrophobicity of the crosslinker play an important role in the catalytic system of the oxidation of AA.

• Journal of Korean Academy of Nursing
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• v.24 no.4
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• pp.568-583
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• 1994

In the changing social and economic conditions, reorientation of the health care system is a process of rearranging health care resources keeping in mind the appropriativeness, relevancy, and efficacy of health care programs. Also it has been recognized recently that the CHP program is in need of review for the same reasons, that is to say, the ease in which health care facilities are available, the high rate of coverage with insurance and the development of an effective transportation system. Therefore there is a social inclination to think that there are no remote areas and to question the roles of public health facilities, health centers, health sub centers and CHP posts. This paper was done to review problems and to propose new directions for the CHP system. The findings of this study are as follows ; 1) It is necessary that primary health care should be simplified into three parts, medical treatment, preventive care services and the organization of administration and logistics. Also each department should be supplemented with the appropriate professional personnel in order to develop a task oriented system. The reorientation of the CHP system should be managed in keeping with that of other public health care systems. Therefore it is necessary to look at the CHP system problems as one aspect of the reorientation process of public health care systems, and to work to find new ways to address these problems. 2) The location of the CHP post should be decided by the needs of the community in both the medical and preventive areas. If the people have a minimum need, the location of the CHP post should be altered and the existing roles of the CHP should be modified to allow for flexibility according to the community needs. 3) Use of the problem solving method in regular team meetings will prove to be as efficient as continuing education programs in improving job competancy. 4) The supervision of CHP's activities should be made by the same type professional personnel, that is, senior CHPs or charge nurses in the public health center at the county level. 5) The operational expensies of CHP post should be supported by the administrative department of the public health center and should create working conditions that will allow the CHP to concentrate on community health service programs. 6) The organizations for community participation, working committees, community health workers and a number of the local assembly, should be activated to provide for participation in finding solutions to health related problems in the com-munity.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.118-124
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• 1997

In the previous study(6), we constructed the CheY-OmpR hybrid, Chp, which affects the expressions of ompF and om pC genes. Here we further characterize these effects and present the regulatory mechanism based on in vivo and in vitro data. Although Chp retained the sequence-specific DNA-binding ability, it was not possible to enhance transcriptional activity, suggesting that it may act as a competitive inhibitor to OmpR. The DNA-binding affinity of Chp was not modulated by phosphorylation of its Che Y portion. Chp was able to increase ompR transcription. FurthemlOre, it was found that the wild-type OmpR also exerts the same effect, which is also eOlltrolled by changes in medium osmolarity and in EnvZ activity.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.251-258
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• 2016

This article reports current status of micro fuel cell-combined heat and power (${\mu}FC$-CHP) systems which utilize both power and heat generated by fuel cells. There are several options for constructing CHP systems and among them, fuel cells are the most useful and their total energy efficiency combining heat and power can reach up to about 90%. Fuel cells are classified as five types based on the electrolyte, but the most suitable fuel cell types for the ${\mu}FC$-CHP system are proton exchange membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs). ${\mu}FC$-CHP systems have several advantages such as decrease of the transmission-distribution loss, reduced costs of electricity due to distributed power generation, and environmental-friendliness owing to zero emission. The main drawback of the ${\mu}FC$-CHP systems is the high initial investment, however, it keeps decreasing as the technology development reduces production costs. Currently, Japan is the most leading country of the ${\mu}FC$-CHP market, however, Korea tries to expand the market by planning the deployment of 1 million units of ${\mu}FC$-CHP systems and governmental subsidiary supporting of half of the install price. In this report, integration technologies for connecting FC and CHP, and technology trends of leading countries are presented as well.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.655-662
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• 2018

To respond effectively to climate change following the launch of the new climate system, the government is seeking to expand the use of distributed power resources. Among them, the district heating system centered on Combined Heat and Power (CHP) is accepted as the most realistic alternative. On the other hand, the government recently announced the change of energy paradigm focusing on eco-friendly power generation from the base power generation through $8^{th}$ Basic Plan for Long-term Electricity Supply and Demand(BPE). In this study, we analyzed the quantitative effects of profit and loss on the CHP operating business by changing patterns of the heat production, caused by the change of energy paradigm. To do this, the power market long-term simulation was carried out according to the $7^{th}$ and $8^{th}$ BPE respectively, using the commercialized power market integrated analysis program. In addition, the CHP operating model is organized to calculate the power and heat production level for each CHP operation mode by utilizing the operating performance of 830MW class CHP in Seoul metropolitan area. Based on this, the operation optimization is performed for realizing the maximum operating profit and loss during the life-cycle of CHP through the commercialized integrated energy optimization program. As a result, it can be seen that the change of the energy paradigm of the government increased the level of the ordered power supply by Korean Power Exchange(KPX), decreased the cost of the heat production, and increased the operating contribution margin by 90.9 billion won for the 30 years.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.12
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• pp.873-880
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• 2010

The present study developed a computer simulation program to determine the optimum strategy and capacity of a micro combined heat and power(CHP) system. This simulation program considered a part-load electrical/thermal efficiency and transient response characteristics of CHP unit. The result obtained from the simulation was compared with the actual operation of 30 kW gas engine driven micro CHP system. It was found that the simulation could reproduce the daily operation behavior, such as operating hours and mean load factor, closely to the actual behavior of the system and could predict the amount of electrical/thermal output and fuel consumption with the error of less than 12%.

• The KSFM Journal of Fluid Machinery
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• v.13 no.6
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• pp.57-62
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• 2010

MW-class gas turbines are suitable for distributed generation systems such as community energy systems(CES). Recently, biogas is acknowledged as an alternative energy source, and its use in gas turbines is expected to increase. Steam injection is an effective way to improve performance of gas turbines. This study intended to examine the influence of injecting steam and using biogas as the fuel on the operation and performance a gas turbine combined heat and power (CHP) system. A commercial gas turbine of 6 MW class was used for this study. The primary concern of this study is a comparative analysis of system performance in a wide biogas composition range. In addition, the effect of steam temperature and injected steam rate on gas turbine and CHP performance was investigated.