• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.10
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• pp.1262-1272
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• 1997

An experimental study on the frequency control of an inverter heat pump to get the desired indoor room temperature has been conducted for the performance characteristics during the steady, 4, 8, and 16 step frequency operations. The heat pump model used in this study was operated to meet the experimental conditions of ASHRAE standard. The performance of the system was tested by measuring the temperature and pressure of the refrigerant, and cooling capacity, power consumption, etc. of the system. As the controlling frequency steps increased, the running time of the compressor increased as well as the electric consumption of the system and the cooling energy due to the wall heating load. However, the average cooling COP was improved.

• New & Renewable Energy
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• v.7 no.2
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• pp.10-17
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• 2011

Korea is the 11th largest energy consumption country and 96% of its total energy consumption depends on imports from overseas. Therefore it is a very important task to secure renewable energy sources which can reduce both the carbon-dioxide emission and dependency on overseas energy imports. Among the various renewable energy sources, organic wastes are important sources. In Korea, 113 million toe of methane is generated from organic wastes annually, but only 3.7% is effectively used for energy conversion. Thus, it is very important to make better use of organic wastes, especially for power generation. The goals of this project are to develope the fuel supplying system of Bio Gasturbine (GT) for 5MW-class co-generation system. The fuel supplying system mainly consists of $H_2S$ removal system, Bio Gas compression system, Siloxane removal system and moisture separating systems. The fuel requirement of 5MW-class GT is at around 60% of $CH_4$, $H_2S$ (<30 ppm), Siloxane(<10 mg/$nm^3$) and supply pressure (> 25 bar) from biogas compressor. Main mechnical charateristics of Bio Gasturbine system have the specific performance; 1) high speed turbine speed (12,840 rpm) 2) very clean emmission NOx (<50 ppm) 3) high efficiency of energy conversion rate. This paper focuses on the development of design technology for food waste biogas pretreatment system for 5MW-class biogas turbine. The study also has the plan to replace the fuel of gas turbine and other distributed power systems. As the increase of bioenergy, this system help to contribute to spread more New & Renewable Energy and the establishment of Renewable Portfolio Standards (RPS) for Korea.

• Architectural research
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• v.17 no.3
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• pp.109-115
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• 2015

The dynamic pricing of electricity, where the electricity rate increases in a time zone with a high demand for electricity is typically applied to a building whose power reception capacity is greater than a certain size. This includes the time of use(TOU) electricity pricing in Korea which can induce the effect of reducing the power demand of a building. Meanwhile, a VRF (Variable Refrigerant Flow) system that uses electricity is regarded as one of the typical heating and cooling systems along with central air conditioning (central HVAC) for its easy operation and application to the building. Thus, to reduce power energy and operating costs of a building in which the TOU and VRF systems are applied simultaneously, we suggested a control for changing the indoor temperature setting within the thermal comfort range or limiting the rotational speed of an inverter compressor. In this study, to describe the features of the above-mentioned control and verify its effects, we evaluated the results obtained from the analysis of its operation data. Through the actual measurements in winter operations for 73 days since mid- December 2014, we confirmed a reduction of 10.9% in power energy consumption and 12.2% in operating costs by the new control. Also, a reduction of 13.3% in power energy consumption was identified through a regression analysis.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.657-668
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• 2023

It's important to note that air compressors in the industrial sector are major energy consumers, accounting for a significant portion of total energy costs in manufacturing plants, ranging from 12% to 40%. To address this issue, researchers have compared forecasting models that can predict the power consumption of air compressors. The forecasting models were designed to incorporate variables such as flow rate, pressure, temperature, humidity, and dew point, utilizing statistical methods, machine learning, and deep learning techniques. The model performance was compared using measures such as RMSE, MAE and SMAPE. Out of the 21 models tested, the Elastic Net, a statistical method, proved to be the most effective in power comsumption forecasting.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.489-494
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• 2006

Electronic and telecommunication industries are constantly trying to develop compact components having high power density. Therefore, a proper heat dissipation method is very important to allow reliable operation of the telecommunication equipment. In this study, a hybrid refrigeration system for a telecommunication equipment room was designed to save energy consumption and improve reliability of the compressor In addition, the performance of the hybrid refrigeration system was measured with a variation of outdoor load. The designed hybrid refrigeration system for the telecommunication equipment shelter saved the energy approximately 50%e at the mode switch temperature of $8.3^{\circ}C$.

• Solar Energy
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• v.19 no.3
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• pp.63-73
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• 1999

Ice storage systems are used to shift the peak load in day time into night time in summer. This paper describes a system simulation of partial ice storage system composed of an encapsulated ice storage tank, a screw compressor chiller, a heat exchanger, and a brine pump. For the system simulation, a one-dimensional model of ice storage tank is developed and validated by comparison with the performance data from measurements of an ice storage tank installed at a building. The control strategies considered in this study are chiller priority and storage priority being used commercially. The system is simulated with design cooling load of 600 RT peak load in design day and with off-design day cooling load, and the electric energy costs of the two control strategies for the same system size are compared. As a result of calculation, the energy consumption in a week for storage priority is higher than that for chiller priority control. However due to lower cost of night electric charge rate, energy cost for storage priority control is lower than chiller priority.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.12
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• pp.1730-1738
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• 2001

This paper presents an overview of testing and analyzing field performance of a centrifugal chiller which has a rated capacity of 200 RT(703 kW). Field data of a chiller installed in the cleanroom research building of KIST has been collected far performance analysis. The operating data included start-up, shut-down, and quasi-static state where cooling capacity and compressor power consumption varied cyclically. It was found that the steady-state thermodynamic model could be applied to relate the cooling capacity and COP under quasi-static conditions. The results led to finding the required cooling load pattern and a possible energy saving method. This study provides a method of evaluating performance of a large capacity centrifugal chiller in which field test is necessary.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_3
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• pp.1205-1213
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• 2023

This study delves into methods for enhancing the power efficiency of air compressor systems, with the primary objective of significantly impacting industrial energy consumption and environmental preservation. The paper scrutinizes Shinhan Airro Co., Ltd.'s power efficiency optimization technology and employs machine learning ensemble models to simulate power efficiency optimization. The results indicate that Shinhan Airro's optimization system led to a notable 23.5% increase in power efficiency. Nonetheless, the study's simulations, utilizing machine learning ensemble techniques, reveal the potential for a further 51.3% increase in power efficiency. By continually exploring and advancing these methodologies, this research introduces a practical approach for identifying optimization points through data-driven simulations using machine learning ensembles.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.10
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• pp.791-799
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• 2006

The fault diagnosis technologies may be applied in order to decrease the energy consumption and the maintenance cost of an air-conditioning system. In this paper, a fault diagnosis algorithm was developed by using a neural no-fault model and a dual fuzzy logic. Five different faults, such as the compressor valve leakage, the liquid line blockage, the condenser fouling, the evaporator fouling, and the refrigerant leakage of an air-conditioning system, were considered. The fault diagnosis algorithm was tested by using a fault simulation facility. Test results showed that the algorithm developed for this study was effective to detect and diagnose various faults. Therefore, this algorithm may be practically used for the fault diagnosis of an air-conditioning system.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.12
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• pp.821-827
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• 2012

Air drying is a technology to dry sludge at the ejector and multi cyclone as intaking and blowing air from outside. So, this technology has a weak point that operating fluctuation is large according to an outside conditions as well as energy consumption is also large due to open loop structure. This is to develop the closed-loop air drying system to be built the dehumidifier consisted of condenser, cooler and compressor at rear side of separator of air dryer, as a way to solve some problem. Air is circulation by the method of blowing-drying-dehumidifying-blowing within this system. It is analyzed that an air circulated at closed-loop air drying equipment contains the energy of 50% more compared with open-loop air drying and is operated regularly because of quality maintenance of air to dry sludge. And also it is analyzed that the cost of drying sludge of 1 ton by closed-loop air drying equipment is lower about 35% than conventional equipment. Therefore, this is evaluated by useful drying technology to face an unexpected climatic conditions due to regular operation as well as low energy consumption.