• KIEAE Journal
• /
• v.7 no.5
• /
• pp.81-86
• /
• 2007

The research analyzes the arrangement of boiler and hot water header, the method of radiator pipe setting, hot water supply control, hourly heating situation of each room for underfloor radiant heating systems in Korea and suggests an alternative to improve to efficient heating method. One of the best options for install position of hot water distributor is under kitchen sink which is center point of all rooms, according to previous research of the energy saving strategies. When the radiator pipes are arranged to each individual room instead of bedrooms through livingroom and kitchen, it has energy saving effects. For rooms without occupancy according to a time period, hot water supply method should be intermittent heating rather than continuous heating. For this intermittent heating method, individual control of hot water supply is more practical, and it can lead to massive energy savings. The intermittent heating system has time-lag, so it is more effective in energy saving with mild and comfort condition if the spaces are preheated by automatic control equipment prior to required time.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.26 no.5
• /
• pp.224-230
• /
• 2014

The purpose of this paper is to investigate the performance of supplemental cooling and heating system equipped with the 1 kW thermoelectric module. The system consist of 96 thermoelectric modules, heat sink with louver fin and water cooling jacket which is attached on the hot side of the thermoelectric module. The cooling and heating performance test of the thermoelectric system is conducted with various conditions, such as intake voltage, air inlet temperature, air flow volume, water inlet temperature and water flow rate at calorimeter chamber in consideration of environmental conditions in realistic vehicle drive. The experimental results of a thermoelectric system shows that the cooling capacity and COP is 1.03 kW, and 1.0, and heating capacity and COP is 1.53 kW, and 1.5 respectively.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.7
• /
• pp.17-25
• /
• 2017

To resolve the problem of the temperature rise in LED or OLED lighting, until now a thick metal film has been used as a heat-sink. Conventionally, this thick metal film is made by the electroplating method and used as the heat-dissipating plate of the electronic devices. However, nowadays there is increasing need for a Cu metal film with a thickness of several hundred micrometers that can be formed by the dry deposition method. In this work, we designed and fabricated a Cu film deposition system where the heating element is separated from the ceramic crucible, which makes ultra-rapid deposition possible by preventing heat loss. In addition, the resulting induction heating also contributes to the high deposition rate. By tuning the various parameters, we obtained a $100-{\mu}m$ thick Cu film whose heat conductivity is high and whose thickness uniformity is better than 2%, while the deposition rate is as high as $1000{\AA}/s$.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.630-633
• /
• 2008

Geothermal heat pump systems use the earth as a heat source in heating mode and a heat sink in cooling mode. These systems can be used for heating or cooling systems in farm facilities such as greenhouses for protected horticulture, cattle sheds, mushroom house and etc. A horizontal type means that a geothermal heat exchanger is laid in the trench buried in 1.2 to 1.8 m depth. Because a horizontal type has advantages of low installation, operation and maintenance costs compared to a vertical type, it is easy to be adopted to agriculture. In this study, to heat and cool farm facilities and obtain basic data for practical application of horizontal geothermal heat pump system in agriculture, a horizontal geothermal heat pump system of 10 RT was installed in greenhouse. Heating and cooling performance of this system was estimated. The horizontal geothermal heat pump used in this study had heating COP of 4.57 at soil temperature of $14^{\circ}C$ with depth of 1.75m and heating COP of 3.75 at soil temperature of $7^{\circ}C$ with the same depth. The cooling COP was 2.7 at ground temperature at 1.75m depth of $25.5^{\circ}C$ and 2.0 at the temperature of $33.5^{\circ}C$.

• Journal of computational fluids engineering
• /
• v.19 no.4
• /
• pp.1-7
• /
• 2014

A numerical study of transient conjugate heat transfer on micro heater in a micro-channel substrate under a sinusoidal heat load was conducted. It was found that the time constant is not affected by the maximum heating magnitude of the sinusoidal heat load. However, the time constant increases with low duration of the sinusoidal heating period and low Reynolds number. Moreover, there is a threshold where a heater temperature do not reach to time constant at low thermal diffusivity, low flow rate, and low pulse duration of the sinusoidal heating. The time constant should be considered for transient convective heat transfer under transient sinusoidal heat load in a micro heat sink.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.752-757
• /
• 2001

The characteristics of heat energy distribution on the fire-proof clay with microwave heating drying are numerically investigated using finite element method. The modelled regular hexahedron chamber$(50cm\times50cm\times50cm)$ filled with air consists of vertical heat source and sink walls, a fire-proof clay model, and adiabatic plates on the top and bottom walls. With different geometrical aspect ratios of the fire-proof clay model, the heat energy distribution is throughly investigated. The model gave a good prediction of the microwave heating characteristics of fire-proof clay. The optimal shape of the fire-proof clay for given chamber geometry and microwave power is analyzed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.24 no.2
• /
• pp.196-203
• /
• 2012

Energy foundations and other thermo-active ground structure, energy wells, energy-slab, and pavement heating and cooling represent an innovative technology that contributes to environmental protection and provides substantial long-term cost savings and minimized maintenance. This paper focuses on earth-contact concrete elements that are already required for structural reasons, but which simultaneously work as heat exchangers. Pipes, energy slabs, filled with a heat carrier fluid are installed under conventional structural elements, forming the primary circuit of a geothermal energy system. The natural ground temperature is used as a heat source in winter and a heat sink in summer. The geothermal heat pump system with energy-slab represented very high heating and cooling performance due to the stability of EWT from energy slab. However, the performance of it seemed to be affected by the atmospheric air temperature.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.171.1-171.1
• /
• 2010

Riverbank filtration wells have been developed to supply a heat source/sink of water in the alluvium aquifer to ground water heat pumps for cooling and heating of a green house. In order to look for an appropriate site to carry out the research, two sites of Jinju and Gumi areas were investigated. In the results of the electrical resistivity surveys, Jinju and Gumi areas have the alluvium aquifer in the depth of 6~17 m and 10~20 m under the ground respectively. Two boreholes have been drilled in each site of both areas. The averaged water level at Jinju site is about 3 m under the ground, and 3.5 m and 6.5 m of sandy gravel aquifer layers are existed in each site. While Gumi site has 10 m water level and 2.5 m and 4.6 m of sandy gravel aquifer. Therefore, it is expected that $1,000m^3$/day of water could be withdrawn at Jinju site rather than Gumi site.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.24 no.3
• /
• pp.230-239
• /
• 2012

Ground-coupled heat pump (GCHP) systems utilize the immense renewable storage capacity of the ground as a heat source or sink to provide space heating, cooling, and domestic hot water. The main objective of the present study is to investigate the cooling and heating performance of a small scale GCHP system with horizontal ground heat exchanger (HGHE). In order to evaluate the performance, a water-to-air ground-source heat pump unit connected to a test room with a net floor area of 18.4 m2 and a volume of 64.4 m3 in the Korea Institute of Construction Technology ($37^{\circ}39'N$, $126^{\circ}48'E$) was designed and constructed. This GCHP system mainly consisted of slinky-type HGHE with a total length of 400 m, indoor heat pump, and measuring devices. The peak cooling and heating loads of the test room were 5.07 kW and 4.12 kW, respectively. The experimental results were obtained from March 15, 2011 to August 31, 2011 and the performance coefficients of the system were determined from the measured data. The overall seasonal performance factor (SPF) for cooling was 3.31 while the system delivered heating at a daily average performance coefficients of 2.82.

• Journal of the Korean Society of Safety
• /
• v.36 no.4
• /
• pp.12-19
• /
• 2021

This paper presents a safety assessment method for FTA-based induction heating systems; the failures and causes of electrical fire are first analyzed for each part and module qualitatively, and methods to manage high probabilities of failure and electrical fire are considered, thereby improving the reliability of the induction heating system. The cumulative importance value (ACC) of the minimal cut set is drawn by setting failure as the top event, and STACK and SMPS are observed to account for about 70% of the induction heating system failures. Thus, intensively managing the basic events contained in the minimal cut set of failures for STACK and SMPS is expected to provide effective and stable operation of the induction heating system. When electrical fire is set as the top event, the STACK percentage is 90%. Accordingly, the current IGBT is changed to a FET to increase the applied voltage and prevent induction heating system failure, and a heat sink plane is installed to prevent FET heating caused by switching, thereby preventing an electrical fire. By classifying the parts and modules of the induction heating system in detail and by applying FTA based on actual failure rates and relevant data, more practical and reasonable results may be expected. Hence, continuous research must be conducted to ensure safety when using induction heating systems.