• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.3
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• pp.155-166
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• 2008

The performance evaluation of a new building is becoming more important because efficient design alone is often not sufficient to deliver an efficient building. However, there is a lack of standard evaluation methods to measure the energy performance of a new construction that has Energy Conservation Design Measures(ECDMs). This study presents an enhanced method based on calibrated whole-building simulation for evaluating the energy performance of new commercial buildings and demonstrates its use using a case-study building, including: an Energy Use Index(EUI) comparison with sub-metered data and an evaluation of the performance of specific ECDMs. The use of this method has determined that the case-study building was shown to use approximately 47% less energy than the base-case building that has the same shape and function as the case-study building(i.e., calibrated as-built simulation mode]), but doesn't include the simulated ECDMs.

• KIEAE Journal
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• v.15 no.6
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• pp.69-80
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• 2015

Purpose: Since most simulation programs take the interface that lists up all the input variables representing all the functionalities, users must know where design variables of an Energy Conservation Measure (ECM) are located and also know what values are appropriate. This is why practitioner designers feel frustrated when they attempt to use simulation. The final objective of this study is to provide a building energy modeling guideline for practitioners in various fields such as architectural design and MEP. Method: As the first step of the modeling guideline, this study provides the Level of Detail (LOD) for simulation modeling of primary ECMs considering the design information available in each design phase. It is prepared by literature review, simulation functionality investigation, and field experts' survey. Result: The proposed simulation LOD offers a milestone at each design phases concerning what design variable and attributes need to be developed with how much of details in order to meet the project goal. Also each design team can set up a simulation usecase considering organizational characteristics based on the proposed LOD.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.31 no.3
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• pp.43-49
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• 2013

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.10
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• pp.879-885
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• 2000

It is a serious subject for energy conservation to prevent the energy loss caused by mixing of heated and cooled air jets in a building which two types of air-conditioning systems are adopted in perimeter and interior zone. The purpose of this paper is to clarify the quantitative and qualitative mechanisms of the mixing loss and to propose preventive methods for it. In this paper, by using the dynamic heat load calculation method, heat extraction loads of a typical office building in Pusan are calculated. According to the results, numerical simulation based on the computational fluid dynamics were peformed in order to measure the mixing loss in physical size HVAC system. Then, the distributions of air temperature and velocity are analyzed in order to grasp the relations by setting temperature differences influence on the mixing loss.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.353-363
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• 2023

The STELLA-2 is a large-scale sodium thermal-hydraulic integral effect test facility and supports the development of PGSFR. The facility adopted Pump Simulation Loop System (PSLS) concept for the mechanical sodium pump in the reference reactor to control and to measure the primary sodium flow. Since the component (mechanical pump) is replaced by the loop, it is very important to evaluate the similarity between the pump and the loop. In this paper, to simulate the characteristic of the mechanical sodium pump, the pressure loss along the various options of the loop was evaluated and the comprehensive validity of each design options was analyzed. Using the similarity criteria based on the Richardson number and Euler number conservation, the PSLS design was finalized and the result was within the acceptable error range. Finally, the result of this study was used for construction of the overall facility, STELLA-2.

• KIEAE Journal
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• v.16 no.6
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• pp.5-12
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• 2016

Purpose: Quasi-steady state simulations have played a pivoting role to expand the user group of simulation to design engineers and architects in Korea. Initially they are introduced in the market as a building energy performance rating tool. In domestic practice, however, quasi-steady state simulations seem to be regarded as a de facto simulation only available for energy retrofit. Selection of ECMs and economic feasibility analysis are being decided through these tools, which implies that running these tools has become a norm step of the Investment-grade Audit. Method: This study aims at identifying issues and problems with the current practice via test cases, analyzing the reasons and opportunities, and then eventually suggesting proper uses of quasi-steady state and dynamic simulations. Result: The functionality of quasi-steady state simulations is more optimized to the rating. If they are to used for energy retrofits, their off-the-shelf functions also need to be expanded for customization and detailed reports. Yet their roles may be limited only to the go/no go decision; because their algorithms are still weak at precisely estimating energy and load savings that are required for making investment decisions compared to detailed simulations.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.46-49
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• 2012

Gears are reliable and efficient power transmission elements. They have been widely used in all kinds of machinery. Nowadays, resource conservation energy conservation environmental improvements from the request of the compact, light weight, high efficiency, low cost Higher efficiency is required. Tooth root and bottom profiles of cylindrical gears affect bending fatigue life, but they are hard to measure with conventional gear measuring machine(GMM), because GMM is normally customized to measure only gear working flanks. The authors try to develop a new type of GMM by installing an extra 3D scanning probe and control software to measure tooth root and bottom profiles. First, in order to measure in various directions, a 3D scanning probe has been attached to the GMM developed. Next, calibration algorithm has been developed. Deviations of the calibration results are measured and it is found that systematic error must be caused by heat from driving motors. A new alternative GMM with driving motors generating less heat was designed and two GMMs are compared. Finally, 3 Dimension measurement of tooth root and bottom profiles of cylindrical gears is described.

• Advances in Energy Research
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• v.4 no.2
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• pp.107-120
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• 2016

The aim of this research is to apply the eQuest model to investigate the energy conservation in a multifamily building located in Dayton, Ohio by using a Trombe wall and an ammonia ground source heat pump (R-717 GSHP). Integration of the Trombe wall into the building is the first retrofitting measure in this study. Trombe wall as a passive solar system, has a simple structure which may reduce the heating demand of buildings significantly. Utilization of ground source heat pump is an effective approach where conventional air source heat pump doesn't have an efficient performance, especially in cold climates. Furthermore, the type of refrigerant in the heat pumps has a substantial effect on energy efficiency. Natural refrigerant, ammonia (R-717), which has a high performance and no negative impacts on the environment, could be the best choice for using in heat pumps. After implementing the eQUEST model in the said multifamily building, the total annual energy consumption with a conventional R-717 air-source-heat-pump (ASHP) system was estimated as the baseline model. The baseline model results were compared to those of the following scenarios: using R-717 GSHP, R410a GSHP and integration of the Trombe wall into the building. The Results specified that, compared to the baseline model, applying the R-717 GSHP and Trombe wall, led to 20% and 9% of energy conservation in the building, respectively. In addition, it was noticed that by using R-410a instead of R-717 in the GSHP, the energy demand increased by 14%.

• Journal of Energy Engineering
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• v.29 no.1
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• pp.25-33
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• 2020

Recently, as the mandatory policy of zero energy building is promoted, policies / systems for transition to Zero Energy School are being promoted, but there is no method to systematically analyze and verify the results of energy saving activities for school buildings. For the study of energy performance verification methodology, the current status of related standards was referred to, and the case study of other methodologies was conducted to examine the tools that can analyze the performance in the field. In addition, this study analyzed the current status and characteristics of energy management through domestic school visits. In this paper, we presented various energy saving projects such as air conditioning and heating facilities, lighting, insulation, change operation behavior, and improve operation methods in new and existing school buildings, and M & V methods for verifying energy savings before and after implementation of energy conservation projects.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.225-227
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• 2004

A sensor networkis composed of a large number of sensor nodes, which are densely deployed either inside the phenomenon or very close to it. One of the most important constraints on sensor nodes is the low power consumption requirement. Sensor nodes carry limited, generally irreplaceable, power sources. Therefore, while traditional networks aim to achieve high quality of service (QoS) provisions, sensor network protocols must focus primarily on power conservation. This paper presents the characteristics of energy consuming, average delay in 802.11 MAC, S-MAC that is specifically designed for wireless sensor networks. We analyze the energy consuming state in the 802.11 MAC in the simulation topology nodes, and measure average delay in 802.11 and S-MAC. Energy efficiency is the primary goal in this protocol design. 802.11 MAC is more efficient than S-MAC in the average delay, throughput. However S-MAC is an energy efficient protocol, a tradeoff between energy efficiency and delay.