Younghoon Kwak

This study investigated the applicability of a tracking photovoltaic (PV) system installed in the roof area of a commercial building. Because PVWatts is the only PV module with a tracking feature in EnergyPlus, its electricity generation was validated through comparisons with detailed PV modules in EnergyPlus. The tracking PV system generated 26.8–35.5% more electricity annually than a fixed system in the climate of Incheon (S. Korea). The load coverage analysis of the tracking PV system was conducted with the reference commercial building model in EnergyPlus. Approximately 14% of the total building electric demand, including heating, ventilation, and air-conditioning; lighting; and equipment, was met by one PV array. Finally, the life cycle cost analysis of the tracking PV system was conducted by considering the net present value, which includes the initial installation and operation costs. The initial investment was returned after approximately 8 years, assuming between two and six tracking PV arrays were installed. Moreover, up to 26.8% cost savings were achieved in 15 years compared to the case without any PV arrays.

To implement smart livestock operations based on information and communication technology, a field monitoring environment based on measured data must be established. Ammonia should be managed more carefully than other environmental monitoring items because it is related to the comfort and production of livestock. Moreover, it is related to odor complaints and environmental protection issues. However, existing studies that propose ammonia measurement standards for each purpose differ from one another or are unclear, and ammonia sensors in the actual field have problems such as durability and management constraints; nonetheless, there is a lack of research on these aspects. Accordingly, for effective ammonia monitoring of smart livestock operations, the necessity of ammonia monitoring for smart livestock operations is first presented, after which a plan for ammonia monitoring of smart livestock operations, supplemented with sensor specifications and maintenance standards, is proposed. This study presents a clear measurement standard based on a comprehensive literature review, as well as an effective monitoring standard reflecting field operation information. This can lead to reliable ammonia data collection and can be a starting point for smooth smart livestock operation.

The behavior of building occupants has been studied by researchers for building control as well as for predicting energy use. In this study, we analyzed the effect of the application of single and complex behavior models on the simulation results of residential buildings. Two occupant behaviors—window opening and closing and air conditioner (AC) usage—were simulated, which are known to be interconnected. This study had two purposes: The first was to integrate data analysis tools (R in this study) and building simulation tools (EnergyPlus in this study) so that two behaviors with interconnectivity could be reflected in building simulation analysis. The second purpose was to apply the behavior models in residential buildings to an integrated simulation environment in stages to analyze their relative influence on the building energy and indoor environment. The results of the study prove that the application of complex behavior is important for research regarding the prediction of actual energy consumption. The results help identify the gap between reality and the existing simulation methods; thereby, they can help improve methods related to energy consumption analysis. We hope that this study and its results will serve as a guide for researchers looking to study occupants’ behavior in the future.

This paper proposes a flexible modeling approach to develop a theoretical reference building (RB) for energy analysis. We designed an RB for five non-residential buildings, using dynamic simulation from statistically analyzed data of building stock in South Korea. For modeling, four subsets of data—form, envelope, system, and operation—were assessed. This study uses the autosizing function within EnergyPlus, to develop the RB. The proposed approach allows for a flexible design where capacities and flow rates of the heating, ventilation, and air-conditioning (HVAC) system match the newly defined RB model. This approach would be ideal for closing the gap between the architectural data and equipment elements. The RB developed in this study allows for performing energy performance analysis by end-use. The analysis results by the end-use can provide support for country-level greenhouse gas (GHG)-mitigation-strategy development.

This paper examines the effectiveness of South Korea’s policy for reducing greenhouse gas (GHG) emissions in office buildings and evaluates if national targets can be met. A sample of office buildings was categorized into two groups—conventional (Group A) and new (Group B)—based on when their construction was approved. Furthermore, data regarding the three design elements of the building envelope, that is building form, window systems, and U-values were collected. By statistically processing data of each element, reference building models were developed and a case study was conducted for each building. Design changes that were incorporated, keeping in mind the GHG reduction policy, showed 13.1% of saving energy in case 8 (reference building of Group B) than case 1 (reference building of Group A). The savings in case 8 were more than the average GHG reduction rate (12.8%) compared to business as usual (BAU). However, case 4 (a conventional (Group A) building form with new (Group B) window systems and U-values) achieved the greatest savings in building loads. The policy to enhance insulation in new buildings to reduce GHG emissions in the building sector has prompted changes in building forms and window systems and has reduced emissions by 10%, that is 3% more than the expected value. Thus, new innovations in building envelope design could achieve an average 12.8% reduction in emissions in buildings.

In this study a quantitative analysis was performed on the effect on thermal comfort of the stand fan, a personal cooling device that creates local air currents. A total of 20 environmental conditions (indoor temperatures: 22, 24, 26, 28, and 30 °C; fan modes: off, low (L) mode, medium (M) mode, and high (H) mode) were analyzed using questionnaires on male and female subjects in their 20s and a thermal manikin test. The contents of the questionnaire consisted of items on thermal sensation, thermal comfort, thermal acceptability, and demands on changes to the air velocity. This step was accompanied by the thermal manikin test to analyze the convective heat transfer coefficient and cooling effect quantitatively by replicating the stand fan. Given that this study provides data on the cooling effect of the stand fan in quantitative values, it allows for a comparison of energy use with other cooling systems such as the air conditioner, and may be used as a primary data set for analysis of energy conservation rates.