• 한국멀티미디어학회논문지
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• 제23권2호
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• pp.155-165
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• 2020

In this paper, we propose a smart thermostat temperature set-point control method based on machine learning and rule engine, which controls thermostat's temperature set-point so that it can achieve energy savings as much as possible without sacrifice of occupants' comfort while users' preference usage pattern is respected. First, the proposed method periodically mines data about how user likes for heating (winter)/cooling (summer) his or her home by learning his or her usage pattern of setting temperature set-point of the thermostat during the past several weeks. Then, from this learning, the proposed method establishes a weekly schedule about temperature setting. Next, by referring to thermal comfort chart by ASHRAE, it makes rules about how to adjust temperature set-points as much as low (winter) or high (summer) while the newly adjusted temperature set-point satisfies thermal comfort zone for predicted humidity. In order to make rules work on time or events, we adopt rule engine so that it can achieve energy savings properly without sacrifice of occupants' comfort. Through experiments, it is shown that the proposed smart thermostat temperature set-point control method can achieve better energy savings while keeping human comfort compared to other conventional thermostat.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.352-357
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• 2007

The objective of this study is to find the optimal set-point of a hybrid Plant, which is combined by renewable energy plant of the GSHP(Ground Source Heat Pump) and the conventional plant(chiller, boiler). The work presented in this study was carried out by using the EnergyPlus(Version 2.0). In order to validate the simulation model, field data were measured from a building. The GSHP was used as a base plant and the conventional plant as the assistant plant. Various temperatures were controlled (zone summer set-point, zone winter set-point, chilled water temperature, hot water temperature) to find the optimal set-point temperature of the system. The influence of the various set-points were analyzed seasonally.

• 설비공학논문집
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• 제27권3호
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• pp.137-145
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• 2015

In this study, the actual energy consumption of the secondary side of District Heating System (DHS) with different hot water supply temperature control methods are compared. Three methods are Set-point Control, Outdoor Temperature Reset Control and Outdoor Temperature Prediction Control. While Outdoor Temperature Reset Control has been widely used for energy savings of the secondary side of the system, the results show that Outdoor Temperature Prediction Control method saves more energy. In general, Outdoor Temperature Prediction Control method lowers the supply temperature of hot water, and it reduces standby losses and increases overall heat transfer value of heated spaces due to more flow into the space. During actual energy consumption monitoring, Outdoor Temperature Prediction Control method saves about 7.1% in comparison to Outdoor Temperature Reset Control method and about 15.7% in comparison to Set-point Control method. Also, it is found that at when partial load condition, such as daytime, the fluctuation of hot water supply temperature with Set-point Control is more severe than Outdoor Temperature Prediction Control. Therefore, it proves that Outdoor Temperature Prediction Control is more stable even at the partial load conditions.

• 한국농공학회논문집
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• 제48권5호
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• pp.51-60
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• 2006

In order to examine the heat transfer characteristic of a soil warming system and effects of soil warming on the greenhouse heating load, control experiments were performed in two greenhouses covered with double polyethylene film. One treated the soil warming with an electric heat wire and the other treated a control. Inside and outside air temperature, soil temperature and heat flux, and heating energy consumption were measured under the set point of heating temperature of $5,\;10,\;15,\;and\;20^{\circ}C$, respectively. Soil temperatures in a soil warming treatment were observed $4.1\;to\;4.9^{\circ}C$ higher than a control. Heating energy consumptions decreased by 14.6 to 30.8% in a soil warming treatment. As the set point of heating temperature became lower, the rate of decrease in the heating energy consumptions increased. The percentage of soil heat flux in total heating load was -49.4 to 24.4% and as the set point of heating temperature became higher, the percentage increased. When the set point of heating temperature was low in a soil warming treatment, the soil heat flux load was minus value and it had an effect on reducing the heating load. Soil heat flux loads showed in proportion to the air temperature difference between the inside and outside of greenhouse but they showed big difference according to the soil warming treatment. So new model for estimation of the soil heat flux load should be introduced. Convective heat transfer coefficients were in proportion to the 1/3 power of temperature difference between the soil surface and the inside air. They were $3.41\;to\;12.42\;W/m^{2}^{\circ}C$ in their temperature difference of $0\;to\;10^{\circ}C$. Radiative heat loss from soil surface in greenhouse was about 66 to 130% of total heating load. To cut the radiation loss by the use of thermal curtains must be able to contribute for the energy saving in greenhouse.

• 한국식품영양학회지
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• 제31권2호
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• pp.272-277
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• 2018

This research was conducted to elucidate the optimum conditions for the antibacterial activity of konjak jelly using the evolutionary operation-factorial design technique. In the first set of experiments, concentration of a coagulation agent, soaking liquid, and temperature of water were set to 0.4%, $0.6{\times}10^{-2}N$, and $65^{\circ}C$ as a central point, respectively. The highest antibacterial activity was acquired at E21, in which the number of bacteria was 1.25 log cfu/g. Because the code of changes in the main effect was (-), it could be decided that the central point of the first set was not the optimum point. Although antibacterial activity in the second set was improved, the values of the main effect were higher than that of changes in the mean effect. The central point of third set was concentration of coagulation agent 0.8%, concentration of soaking liquid $1.0{\times}10^{-2}N$, and temperature of water $65^{\circ}C$. It was found that the antibacterial activity of central point in the third set was highest among all the tested set. Further, all the necessary conditions were appropriate to reach the optimum condition. The antibacterial activity of the central point in third set was more than 1,000 times higher than that of E11, in first set.

• 한국의류산업학회지
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• 제6권5호
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• pp.613-617
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• 2004

The intent of this study was to determine whether different light exposure could modify the clothing behavior in the evening cold environment or not. Nine female subjects volunteered to this study. In a bright light or a dim light condition, light intensity was controlled 3000 lx or 10 lx respectively. Subjects were introduced to wear various kinds of garments whenever they need to feel comfortable as the room temperature began to decrease. The room temperature was lowered from $30^{\circ}C$ to $15^{\circ}C$ for one hour (21:00 h~22:00 h) and maintained at $15^{\circ}C$ for additional one hour (22:00 h~23:00 h). Subjects stayed in chamber from 08:00 to the next day 07:00. Clothing behavior, core temperature, subjective temperature sensation and melatonin secretion were measured. Most subjects put on the clothing more quickly and more thickerly in the bright light rather than in the dim light condition. The fall of core temperature during night was significantly less under the bright light in the late afternoon, suggesting that the set-point of core temperature has been set at a higher level during the evening and the night, being supported by the less amount of melatonin secretion. Thus, it is concluded that the quicker dressing behavior with thicker clothing in the "Bright" condition is advantageous in evening cold exposure, since it enables the core temperature to reach its set-point value more easily.

• 한국주거학회논문집
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• 제14권5호
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• pp.75-82
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• 2003

In this study, the thermal performance of the room control system is analyzed in terms of control performance, potential for coil expansion and energy consumption through experiments comparing the individual room control system and an existing system. The results of this study show that the existing system is not able to supply design water flow rate and does not accurately maintain the set point temperature in each room. However, the individual room control system can set a room air temperature for each room, for it is able to supply design water flow and accurately control the set point temperature in each room and can reduce the energy consumption compared to the existing system. Moreover, the individual room control system can reduce the number of coil division zone and facilitates the construction process, because it can extend the length of the coil division.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.46-51
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• 2007

The near-optimal control algorithm for central cooling system has been developed for minimizing energy consumption while maintaining the comfort of indoor thermal environment in terms of the environmental variables such as time varying indoor cooling load and outdoor temperatures. The optimal set-points of control parameters with near-optimal control are supply air temperature and chilled water temperature. This study has been done by using LapVIEW program with PID control in order to analyze the central cooling system energy saving.

• 한국지열·수열에너지학회논문집
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• 제6권1호
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• pp.1-7
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• 2010

In this paper, an experimental study on the cooling operation characteristics for different entering water temperatures in geothermal heat pump system are carried out by using Lab VIEW system program Set-point temperature controls for cooling water and supply air temperatures is applied to analyze the energy consumption and control performances. As a result, the system responses show that different entering water temperatures(EWT) effect greatly on the energy consumption and system COP.

• International Journal of Advanced Culture Technology
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• 제4권2호
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• pp.47-56
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• 2016

In transformer cooling systems, oil temperature is controlled through the use of a blower and oil pump. For this paper, set-point algorithms, a reset algorithm and control algorithms of the cooling system were developed by neural networks and fuzzy logics. The oil inlet temperature was set by a $2{\times}2{\times}1$ neural network, and the oil temperature difference was set by a $2{\times}3{\times}1$ neural network. Inputs used for these neural networks were the transformer operating ratio and the air inlet temperature. The inlet set temperature was reset by a fuzzy logic based on the transformer operating ratio and the oil outlet temperature. A blower was used to control the inlet oil temperature while the oil pump was used to control the oil temperature difference by fuzzy logics. In order to analysis the performance of these algorithms, the initial start-up test and the step change test were performed by using the dynamic model of a transformer cooling system. Test results showed that algorithms developed for this study were effective in controlling the oil temperature of a transformer cooling system.