• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.341-346
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• 2005

Nowadays, adsorption chillers have been receiving considerable attentions as they are energy-saving and environmental1y benign systems. A Fin & tube type heat exchanger in which adsorption/desorption take place is required more compact size. The adsorption chiller is expected to have high energy-efficiency in utilizing the waste heat exhausted from a process. The objectives of this paper are to investigate the effect of fin pitch of fin & tube on the adsorption performance and to develop an optimal design fin & tube heat exchanger in the silica gel/water adsorption chiller. Previous study concluded that optimal particle size selected 0.5mm, type HO silica gel, and fundamental heat transfer & mass transfer experiments carried out. From the numerical results, the adsorption rate for the fin pitch 2.5mm is the highest than that for the fin pitch 5mm, 7.5mm and 10mm. Also cooling water & hot water temperature affect the adsorption rate.

• 설비공학논문집
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• 제27권1호
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• pp.39-43
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• 2015

The Energy and Green House Gas target management system was launched by the Korean Government in 2010. The Korea Emission Trading System will start in 2015. Therefore, simultaneous pursuit of energy saving and greenhouse emission reduction through energy use rationalization is an important obligation of Korean engineers, who import about 97% of domestic energy consumption. Economic analysis of the GHG emission reduction methodologies registered and approved by Korea Voluntary Emission Reduction (KVER) program was conducted. The results for waste heat recovery employed in an energy intensive pulp, paper and wood industry were reported. The emission reduction intensities were 9.7 kg $CO_2$/ton_pulp production. Net Present Value analysis showed that the GHG emission reduction was economically beneficial with an internal rate return of 60%. The results of exergy analysis indicated that the second law efficiencies of waste heat recovery system employed in KVER program were 77.3% and 53.6%. NPV decreased as the exergy decreased.

• 전기학회논문지P
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• 제63권1호
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• pp.34-39
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• 2014

In cognitive radios, secondary users can use the spectrum exclusively allocated to a primary wireless system if the secondary users detect the spectrum in idle states. Because the secondary users can utilize the idle state of the spectrum, the utilization rate of the spectrum can be improved. The idle states can be detected by using secondary users' sensing schemes. However, the wireless channel environment where secondary users perform the spectrum sensing is not very friendly to secondary users because the signal-to-noise ratio of the received primary signal is very low. Hence, cooperative sensing scheme where more than one secondary user take part in the spectrum sensing is generally used in cognitive radios. In this paper, we investigate the cooperative sensing performance for machine-to-machine communication devices operated by batteries with limited energy. In general, the energy consumed for the spectrum sensing increases as the length of the sensing period and the number of cooperative sensing nodes. Accordingly, even though the total amount of the consumed energy is the same, an energy allocation methodology how to distribute the energy to the sensing period and sensing nodes can achieve the optimum sensing performance, which is numerically analyzed.

• KIEAE Journal
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• 제12권1호
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• pp.105-112
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• 2012

When a building is planned and designed, the design should be able to minimize the cost during the whole life cycle of the building. This study has begun to analyze LCC about the alternative design which is applicable to renewable energy facility construction. It is reviewed domestic and foreign papers about the trend of LCC technology and it is determined the analytical method to analyze the LCC of renewable energy. Regarding the review of alternatives, it is chosen the three alternatives which are able to designed combing the renewable energy facilities and it is performed the LCC analysis about each alternative. Alternative 1 is Photovoltaic + Solar Thermal + Photovoltaic /Wind Power, Alternative 2 is Geothermal + Photovoltaic, and Alternative 3 is Photovoltaic + Solar Thermal. The LCC analysis is present value method, its analytical period is 40 years and it is applied 3.2% of real discount rate. As a result, it is proved that Alternative 1 and Alternative 3 are not able to collectible the early investment cost during the analytical period and Alternative 2 is analyzed that its pay-back period of early investment cost is about 31 years. As the final outcome of this study on case analysis, it is more advantageous to use the combination of Geothermal and Photovoltaic energy than to use the other combination in LCC aspect.

• KIEAE Journal
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• 제9권1호
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• pp.85-90
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• 2009

The indoor air quality is one of the most important issues of designing ventilation in high rise apartment buildings. This study suggested proper ventilation rate in the apartment bedroom where mechanical ventilation system has installed. Six university students(four male and two female) were participating in the experiment. Experiments were performed in environmental chamber. Experimental conditions were combinations from three ventilation rate 0, 0.4 and 0.7. Measurement items during 8 hours of experimental time were temperature, humidity, carbon dioxide concentrations and questionnaire surveyed aftrer sleeping. The concentration of Carbon Dioxide depending on ventilation rate in the chamber was analyzed for proper ventilation rate. The results of this paper can be summarized as follows. (1) When two persons experiment, 0.7 ventilation rate was in excess of 1000ppm. (2) When one person experiment, 0.7 and 0.4 ventilation rates were satisfied the criteria of IAQ. (3) It compared 0.4 with 0.7 in the ventilation rate, 0.4 ventilation rate could reduced about 80% of the power by fan similarity law.

• 설비공학논문집
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• 제25권7호
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• pp.392-397
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• 2013

To fulfill the demands concerning energy efficiency for zero energy buildings, various technologies of architects and engineers are required. This study aims to estimate the thermal performance of heat source equipment in which part load characteristics are considered in an office building. Overestimation of heat source equipment was reviewed through literature survey, and heating and cooling loads depending on the capacity and division of the equipment were analyzed through a simulation program (DOE-2.1E). The conclusions gained from this study are as follows; 1) The more the division of equipment, the less the heating and cooling energy consumption. 2) When a large item of equipment is divided into two small items of equipment, the optimum application rate showed as 5:5 for chiller, and 7:3 for boiler, respectively.

• 자원ㆍ환경경제연구
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• 제20권2호
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• pp.291-308
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• 2011

정부의 '저탄소 녹색성장' 정책기조의 실현가능성 여부는 에너지절약 자본시설에 투자할 경우 과연 산업의 생산성 증가로 이어질 수 있는지 여부에 달려 있다. 본 논문에서는 1차 금속산업을 대상으로 쌍대 비용함수로부터 총 요소생산성을 정의하고 산업생산성 증가의 요인별 분석을 통하여 에너지효율화 투자의 생산성 증가 파급효과를 측정하였다. 1982년~2006년 기간 동안 에너지효율화 투자로 인하여 평균적으로 연간 생산성은 1.16% 포인트 증가한 것으로 추정되었다. 또한 규모경제효과는 에너지효율화 투자의 생산성 증가 기여도를 향상시키는 것으로 나타났다.

• 설비공학논문집
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• 제16권1호
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• pp.26-33
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• 2004

In general, an absorption chiller or heat pump is operated under the constant cooling water flow rate condition even though the system works with a partial load. The objective of this paper is to study the effect of the cooling water flow rates and the temperature of cooling water on the system performance to find the energy saving methode for the partial load operation of the double effect $H_2O$/LiBr absorption chiller. It is found that the performance of the system is sensitive to the temperature of cooling water than the cooling water flow rate, so the decrease of the performance due to reducing the cooling water flow rate can be overcome with the reduction of the cooling water temperature by 1$^{\circ}C$. The flow rate of the cooling water flow rate ranges from 50％ to 100％ of the flow rate at normal conditions with a partial load. It is also found that the operation cost of the cooling water pump and the cooling tower can be reduced by 23％.

• 설비공학논문집
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• 제21권1호
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• pp.49-54
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• 2009

Ventilation requirement of apartment was mandated according to building equipment standards in 2006. When ventilation unit was considering for indoor air quality maintenance, we needed energy saving and efficiency ventilation control methods. This study carried out experiment of ventilation rate 0.7 adequacy. When we lived in apartment, we assumed that sleeping time was long stayed time in unconsciousness. Experiments carried out ventilation rate 0, 0.1, 0.4 and 0.7 in environment chamber from 22 o'clock to 06 o'clock, the concentration of $CO_2$, temperature and humidity rate measured. Analyzing the results, conclusions are as follows. 1) When we sleep in bedroom, ventilation rate 0.4 meet the requirements of domestic legal standards. Conform fan of similarity law, ventilation rate 0.4 reduced power cost about 80% than 0.7. 2) In generally sleeping time 8 hours, peak point control reduced running time of ventilation unit about 43% than normal control.

• 한국통신학회논문지
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• 제34권10A호
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• pp.760-768
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• 2009

본 논문에서는 선박에 적용할 e-네비게이션을 위한 HR(high rate)-WPAN(Wireless Personal Area Network) 시스템에 대한 전송 파라미터를 분석하여 최적 전송파라미터 선택방식을 제시한다. 본 논문에서는 IEEE 802.15.3 CSMA/CA기반의 HR-WPAN을 SAN(Ship Area Network)에 적용할 경우에 고려되어야하는 에너지 효율성 측면에서의 전송파라미터들을 분석하고 에너지를 절약할 수 있는 전송파라미터 결정방식에 대하여 각 선박환경별로 분석하여 제안한다. 특히 SAN환경에서 무선채널의 경로손실(path loss)을 결정하는 가장 큰 파라미터인 선박의 다양한 재질을 고려하여 각 HR-WPAN의 전송파라미터별로 에너지 소모량을 분석하여 파라미터 선택방안을 제시한다. 시뮬레이션 결과 선박환경에 따라서 전송률 선택방식, 전송전력 조절 방식 및 데이터 분할크기의 적절한 선택에 따라 에너지 효율성능이 결정됨을 보였다.