Lee W.-N.,Konkuk University |
Kim H.-J.,Korea Energy Management Corporation |
Park J.-B.,Konkuk University |
Cho K.-S.,Korea Electrotechnology Research Institute |
And 2 more authors.
Renewable and Sustainable Energy Reviews | Year: 2012
Energy flow from the primary energy to the final energy use varies depending on which device is used for the heating and cooling energy service. This paper presents economic analyses of medium capacity space heating and cooling systems from three perspectives - primary energy, final consumer, and social cost perspective. From the analysis results of primary energy and final consumer perspective, electric heat pump (EHP) system is found to be superior to the gas engine driven heat pump (GHP) system for the energy consumption and cost-effectiveness due to its higher system efficiency. However, the result of social cost perspective shows the GHP system is superior to the EHP system considering incurred incremental electricity generation capacity construction cost and avoided gas storage tank construction cost due to a new installation of each system. And this paper suggests three analysis methodologies - the primary energy, final consumer, and social cost perspective - can be used for developing various measures and policies for integrated demand side management. © 2012 Elsevier Ltd. All right reserved.
Oh M.-W.,Korea Electrotechnology Research Institute |
Kang T.-G.,Korea Energy Management Corporation |
Ryu B.,Korea Electrotechnology Research Institute |
Lee J.E.,Korea Electrotechnology Research Institute |
And 5 more authors.
Journal of Korean Institute of Metals and Materials | Year: 2014
Electronic structures and X-ray absorption spectra of rutile TiO2were obtained with the firstprinciples calculation. Density of states, charge density and differential charge density were obtained, from which charge transfer characteristics between Ti and 0 was well confirmed. Direct and indirect band gap of 1.99 and 2.03 eV were evaluated, respectively. X-ray absorption spectra of rutile TiO2was also calculated, in which the gap between main peaks was comparable with experiment. From band structure calculations, anisotropic electrical transport properties were expected, which was in good agreement with experiment. © The Korean Institute of Metals and Materials.
Cho S.-H.,Jeonju University |
Kim H.-J.,Korea Energy Management Corporation |
Zaheeruddin M.,Concordia University at Montreal
Building Services Engineering Research and Technology | Year: 2011
Because of the rapid rise in ambient temperatures in urban cities due to global warming, this research study was conducted to revise the heating degree days (HDDs) for main cities of South Korea. Current HDDs used in the design of heating systems were established some 30 years ago. Therefore, there is a need to revisit and revise the HDDs used in Korea. The HDDs were computed at five different indoor set-point and unloaded temperatures. The validity of the methodology used for computing HDDs was ascertained by comparing the calculated HDDs with the published values. The impact of the length of time on total annual HDDs was examined. The results show that higher temperature trends due to global warming witnessed over the past decade in general decreased the HDDs. The impact was higher for warmer climate cities than the cold regions. The revised annual HDDs for 15 major cities of South Korea are presented in this paper.Practical applications: The HDDs corrected for global warming effects for 15 major cities of South Korea presented in this article are useful for designers in estimating the impact on equipment size and energy consumption. Towards this end, several scenarios of global warming effects are presented by assuming several unloaded temperature levels. This is useful for the designers in examining the uncertainties in the estimation of energy consumption. The results published are also important for policy makers in South Korea to examine the need for revising the degree day database in light of the global warming trends. © The Chartered Institution of Building Services Engineers 2011.
Song B.J.,Korea Research Institute of Chemical Technology |
Song B.J.,Sungkyunkwan University |
You N.,Korea Research Institute of Chemical Technology |
Lee J.H.,Korea Research Institute of Chemical Technology |
And 2 more authors.
Applied Chemistry for Engineering | Year: 2014
SAGD (steam assisted gravity drainage) process is the most commonly used in-situ technology for the recovery of bitumen from oil sand. It was investigated that the effects of different additives on bitumen recovery rate from oil sand in SAGD process among many possible mechanisms studied throughout the study. Bitumen recovery from thin layer oil sand reservoirs was simulated by using an experimental SAGD apparatus with scale of 150:1. To improve the simulation accuracy of thin layer oil reservoir, we have attached geological model (GM). Oil sand was simulated by using a mixture of extra heavy oil and glass beads with a diameter of 1.5 mm. CO2 was used as an additive and the evolution of steam chambers were closely monitored, and the effects of CO2 as an additive was investigated. Two types of injection methods were tested; continuous (cCO2-SAGD) and sequential interruption (sCO2-SAGD) CO2 injection. For the sCO2-SAGD experiment, it was observed that the recovery rates and CSOR were efficiently improved control experiment from 60.2% to 69.3% and 7.1 to 6.0, respectively, whereas cCO2-SAGD experiment decreased from 60.2% to 57.6% and 7.1 to 7.3. © 2014 The Korean Society of Industrial and Engineering Chemistry. All rights reserved.
Kwak H.-Y.,Chung - Ang University |
You Y.,Blue Economy Strategy Institute |
Oh S.-D.,Blue Economy Strategy Institute |
Jang H.-N.,Korea Energy Management Corporation
International Journal of Energy Research | Year: 2014
A thermoeconomic analysis of a ground-source heat pump (GSHP) system with a vertical or horizontal ground heat exchanger, a type of heat delivery system, was performed using the modified productive structure analysis method. In this analysis, the unit cost of geothermal heat delivered to a room using GSHP system was estimated. The unit cost of heat delivered was calculated to be $0.063/kWh for input of electricity with a unit cost of $0.140/kWh for a GSHP with a coefficient of performance (COP) of 3.27. Exergy destruction and monetary losses due to the irreversibility that occurs at each component of the system were also estimated. The unit cost of heat was found to be inversely proportional to the COP of the heat pump and proportional to the electricity input. The greatest monetary loss occurs in the geothermal heat exchanger in which considerable mass of brine flows in long pipes and in the fan-coil unit which features a complex configuration of pipes in the air passages, respectively. © 2013 John Wiley & Sons, Ltd.