This paper shows scheduling methods to utilize heat pump systems as demand response resources in the smart grid environment. The heat pump system has a partial thermal storage tank which could be used at any time according to the consumer behavior based on the real time electricity tariff system. Some scheduling methods are proposed and an optimization basis is established considering areas, insulation conditions, heating set temperature, minimum heating maintaining period of thermal storage, maximum size of tank, etc.
In the study, space cooling performance of air source heat pump(ASHP) was evaluated in a pilot house. The ASHP, which provide for floor heating, domestic water heating and space cooling/heating, shows cooling capacity of 14.0 kW, when COP of ASHP was 3.21 based on test performance of KS C 9306. Test results shows that cooling capacity was depended on frequency of the compressor. The variable refrigerant flow rate for cooling were supplied into diverse room by using LEV. The COP at setting room temperature of 26℃ was 6.3% higher than the COP at that of 24℃, when the spending time in operation was decreased as 21.2%.
Structural insulated panels, which are structurally performed panels consisting of a plastic insulation bonded between two structural panel facings are one of emerging products with a viewpoint of its energy and construction efficiencies. These components are applicable to fabricated wood structures. By now, there are few technical documents regulated structural performance and engineering criteria in domestic market. This study was conducted to suggest fundamental reports such as racking resistance, axial capacity, transverse load capacity, and lintel load capacity for SIPs. Test results showed that maximum load was 44.3kN, allowable load was 14.7kN for racking resistance, and that maximum load was 137.6kN, allowable load was 37.4kN/m for axial compression capacity. For transverse load capacity, test results showed 10.3kN/㎡ of maximum load, 3.4kN/㎡ of allowable load. For lintel load capacity for SIPs dependent to lengths, allowable loads were 20.4kN for 600㎜ long lintel, 23.9kN for 1,200㎜ long lintel, 19.3kN for 1,800㎜ long lintel, and 2,400㎜ long lintel had 14.1kN of allowable load. In the near future, when the allowable load for wall application is established, SIPs is considered to substitute the existent post-and-lintel construction to bearing wall structure.
To analyze and verify the effect of replacing thermal storage heater by a cascade cycle heat pump using midnight electricity was installed and tested at a customer's house in Wonju, Korea. The electric night storage heater is consist of 30kW electric heater and 2,700 liters of thermal storage water tank to supply hot water for warming house floor. The power for electric heater was cut off and hot water was only generated by cascade cycle heat pump. Current thermal storage water tank was not eliminated and electric heater wiring was modified. Some operation logic of the heat pump was also modified for proper operation. The required capacity of the heat pump and hot water temperature for given warming condition were estimated. The estimated capacity of heat pump was about 19kW and estimated hot water temperature for proper heating was at least 75℃.
Recently, all-electrified houses have constructed and some tasks are being carried out to monitor energy consumption patterns. The energy monitoring includes various elements such as temperature, pressure, water flow, CO2, and electricity. In this monitoring, electricity consumption is one of the essential factors because the performance and energy saving levels are described by this physical quantity. This quantity depends on materials, structure, operation of the house, which operation means consumer's life style and usage patterns of home appliances furthermore. Firstly, this paper shows a control simulation method which were developed a few years ago. And some different methods are proposed considering flexible experimental condition.
The cost to electricity is cheaper at night due to electric supply and demand policy in Korea. During daytime the loads are higher and extra generators are brought "on-line" to meet the demand. In the middle of night loads are lower and they need to throttle back the generators. So KEPCO (Korea Electric Power Corporation) offers "time of use" (TOU) rates to balance the grid load. The night storage heaters are generally on a separate circuit which is only switched on when the night rate is activated. Since 2000 the price of NG, kerosene and other petroleum based fuel for heating has been increased rapidly and overtook the price of electricity at last, so more and more people have chosen night storage heaters to save energy price. Currently about 900,000 customers are using electric night heaters and this causes shift of peak demand time to night in winter and increase of deficit spending. To solve this problem, replacing electric night heater by air-source heat pump has been proposed. An air-source heat pump can provide efficient heating and cooling for building, especially in a warm climate. When properly installed, an air-source heat pump can deliver one-and-a-half to three times more heat energy to a building than the electrical energy it consumes. This is possible because a heat pump moves heat rather than converting it from a fuel, like in combustion heating systems.
In this paper, the situation of energy efficiency standards and MEPS (Minimum Energy Performance Standard) for motors and diffusion states are analyzed. For this purpose, a new methodology is used, which was proposed in the existing study, using diffusion models and learning curves. The existing diffusion models could not explain affects from new appliances' penetration during the diffusion. But a mixed diffusion model with learning curves or learning ratio is studied to explain this penetration.
The purpose of this study was to conduct a forest healing program for victims affected by the large forest fires of 2017 in Gangneung and to investigate its effects on the stress and physical health promotion of the victims. From January to March 2019, three forest therapy programs were conducted on 49 residents of four villages that suffered forest fires in the National Center for Forest Therapy, Daegwallyeong. The results showed that the degree of stress of forest fire victims decreased significantly by means of these programs. Furthermore, autonomic nerve activity, stress resistance, stress index, and fatigue decreased significantly and average heart rate and heart stability also improved.