• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.1
• /
• pp.131-139
• /
• 2018

Many ship researches have been carried out in connection with the fourth revolution, one of which focuses on EMS(energy management system). The EMS is referred to as systems for managing the energy of ships and include various systems. In this paper, we analyze the energy saving field in ship and propose a ship power energy management system including individual load control systems that can save energy in the engine room. EMS includes individual load control systems of PCS (Pump Control System), ERFCS (Engine Room Fan Control System), LCS (Load Control System), HVACS (Heating, Ventilation, Air conditioning Control System). Proposed EMS primarily conserves energy in the individual load systems of the engine room. Secondly, the integrated monitoring and control system is used to control the power generation system and the power load system to save energy.

• 한국태양에너지학회:학술대회논문집
• /
• 2008.04a
• /
• pp.342-347
• /
• 2008

A Microsoft $Access^{(R)}$ application that estimates hourly building energy load is developed based on statistical field measurements. Hourly patterns of heating, hot water, cooling, and electricity loads are evaluated for an energy consuming community composed of various types of buildings. Popular building types such as apartments, offices, hotels and accomodations, stores, churches, schools and educational institutes are included in the model. For each type of buildings, hourly patterns for a month are measured and compiled to derive a 24-hour load distributions. Daily sum of heating, hot water, cooling, and electricity loads are also measured for the building types. The annual energy need profiles are generated by combining the 24-hour distribution and 365-day consumption patterns. The annual maximum values of the 8760 hours of a year for each load type serves as a guide for selecting a device capacity. A user-friendly interface that ushers users throughout the whole process is provided.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.24 no.10
• /
• pp.733-738
• /
• 2012

It is important issue to reduce the electric energy to save the operating cost of HVAC system. Even if electrical energy is the clean energy, it is difficult and takes high cost for storage of electricity. These cause the high peak load of electric energy for HVAC in summer season. In korea, government impose the electric charge with several grade for the purpose of cut-off the peak load of electricity. Government has a policy to support to design and install the heat/ice storage system using midnight electricity. In this study, analysis of cooling load and operating characteristics for ice storage system are performed. And, also economical efficiency is compared between ordinary charge system of electricity and midnight rate charge of electricity. The systematic and economical supports are needed for expansion of usage of energy saving equipments.

• Journal of the Korean Solar Energy Society
• /
• v.24 no.4
• /
• pp.77-87
• /
• 2004

BIPV or double skin applied to the surface of the building, power and thermal load cannot both be increased. In the case of BIPV, because it is applied to the facade, incident solar energy decreases and efficiency drops off. The system in this paper complements these disadvantages and aims to decrease the heating & cooling load by transforming solar energy to electronic and thermal energy. The research in this paper is about the applicability of the clear PV attached double-skin system. And the PV electronic generation and the factors that affect the heating & cooling load such as the daily radiation, sun shading ratio, heating & cooling load, daylight luminance and glare distributions in the building are simulated.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.3
• /
• pp.1132-1136
• /
• 2014

In the context of increasing electric energy consumption in a data center, energy efficiency improvement is strongly emphasized. In a data center, electric energy is largely consumed by DC power supply system, which is based on a rectifier composed by multiple parallel converters. Therefore, rectifier efficiency must be improved for minimizing loss of DC power supply system. Rectifier efficiency can be modulated by load allocation to converters because converter efficiency depends on input AC power. In this paper, we propose a new control method to maximize rectifier efficiency. The method can control load allocation to converters by introducing active power converter control scheme and start-and-stop of converters. In order to illustrate optimal load allocations in a rectifier, a maximization problem of rectifier efficiency is formulated as a nonlinear optimization one. The problem is solved by Lagrangian relaxation method and the computation results provide the validity of proposed method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.27 no.9
• /
• pp.455-462
• /
• 2015

Residential buildings account for a significant portion of the total building-energy usage in Korea, and a variety of research studies on the domestic boiler have therefore been carried out; however, most of these studies examined the boiler itself, whereby the part-load ratio characteristics and the corresponding gas-energy consumption patterns were not analyzed. In this study, the part-load ratio and operating characteristics of a domestic gas boiler were analyzed within a residential building equipped with a radiant floor-heating system; in addition, the energy consumption between condensing and conventional boilers was comparatively analyzed. Our results show that significant portions of the total operating hours, heating load, and energy consumption are in the part-load ratio range of 0 through 40%, whereby the energy consumption was significantly affected by the boiler efficiency under low part-load conditions. These results indicate that the part-load operation of a boiler is an important factor in residential buildings; furthermore, replacing a conventional boiler with a condensing boiler can reduce annual gas-energy usage by more than 20%.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.29 no.2
• /
• pp.43-50
• /
• 2017

The purpose of this study is to develop a control algorithm for outdoor air cooling based on the prediction of cooling load, and to evaluate the building energy saving using outdoor air cooling. Outdoor air conditions such as temperature, humidity, and solar insolation are predicted using forecasted information provided by the meteorological agency, and the building cooling load is predicted from the obtained outdoor air conditions and building characteristics. The air flow rate induced by outdoor air is determined by considering the predicted cooling loads. To evaluate the energy saving, the benchmark building is modeled and simulated using the TRNSYS program. Energy saving by outdoor air cooling using load prediction is found to be around 10% of the total cooling coil load in all locations of Korea. As the allowable minimum indoor temperature is decreased, the total energy saving is increased and approaches close to that of the conventional enthalpy control.

• Advances in aircraft and spacecraft science
• /
• v.2 no.3
• /
• pp.345-365
• /
• 2015

This paper focuses on the design, fabrication, testing and analysis of a novel load-bearing element with energy dissipation capability. A single element comprises two von-Mises trusses (VMTs), which are sandwiched between two plates and connected to dashpots that stroke as the VMTs cycle between stable equilibrium states. The elements can be assembled in-plane to form a large plate-like structure or stacked with different properties in each layer for improved load-adaptability. Also introduced in the elements are pre-loaded springs (PLSs) that provide high initial stiffness and allow the element to carry a static load even when the VMTs cannot under harmonic disturbance input. Simulations of the system behavior using the Simscape environment show good overall correlation with test data. Good energy dissipation capability is observed over a frequency range from 0.1 Hz to 2 Hz. The test and simulation results show that a two layer prototype, having one soft VMT layer and one stiff VMT layer, can provide good energy dissipation over a decade of variation in harmonic load amplitude, while retaining the ability to carry static load due to the PLSs. The paper discusses how system design parameter changes affect the static load capability and the hysteresis behavior.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.21 no.10
• /
• pp.553-558
• /
• 2009

Energy demand characteristics of hotel, hospital, and office building are compared to provide guidelines for combining building in community energy system design. The annual, monthly, and daily energy demand patterns for electricity, heating, hot water and cooling are qualitatively compared and important features are delineated based on the energy demand models. Key statistical values such as the mean, the maximum are also provided. Important features of the hourly demand patterns are summarized for weekdays and weekends. Substantial variations in both magnitudes and patterns are observed among the 3 building types and smart grouping or combination of building type and size is essential for a successive energy supply.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.21 no.11
• /
• pp.636-642
• /
• 2009

Energy consumption data are surveyed and measured to develop energy demand models for hospital buildings as part of a complete package. Daily consumption profiles for electricity, heating, cooling and hot water are surveyed for 14 carefully chosen hospitals to establish energy demand patterns for a time span of a year. Then the hourly demand patterns of the 4 loads are field-measured for different seasons and statistically analyzed to provide higher resolution models. Used in conjunction with energy demand models for other types of buildings, the high resolution of 8760 hour energy demand models for a hospital for a typical year will serve as building blocks for the comprehensive model that allows the estimation of the combined loads for arbitrary mixtures of buildings.