• Food Science and Preservation
• /
• v.14 no.5
• /
• pp.487-491
• /
• 2007

This study was conducted to investigate the effect of treatment with squeous chlorine dioxide and hot water on the germination of radish (Raphanus sativus L.) seeds, and reduction of microbial load on the seeds. Increases in treatment and the concentration of aqueous chlorine dioxide in water resulted in increasing reductions in the counts of total aerobic microbes. Seeds treated with aqueous chlorine dioxide (100 ppm/20min, 200ppm/20min) showed about a 10-fold decrease in microbial loads. Germination of seeds was not adversely affected by any treatment tested, although the germination rate of seeds in the group treated at $55^{\circ}C$ for 20 min was reduced by 10% compared to that of control. Combined treatment with hot water and aqueous chlorine dioxide yielded better out comes in both microbial reduction and seed germination rate than did single treatments. A combined treatment with 100 ppm aqueous chlorine dioxide and hot water($45^{\circ}C$ or $50^{\circ}C$) resulted in about a 100-fold decrease in microbial load whereas germination rate showed only a slight increase to $97.0{\sim}97.7%$. Total aerobic microbial counts in radish seeds were decreased by aqueous chlorine dioxide and hot water treatment in the order. aqueous $CIO_2$+ hot water > aqueous $CIO_2$ > chlorinated water > hot water > control.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.5
• /
• pp.296-303
• /
• 2010

An experimental study was carried out to investigate performance characteristics of the hybrid solar system during spring season. The system operating condition, each load, and heat pump performance were analyzed with the cloud cover. As a results, the collector heat, solar fraction, and hot water load were decreased with a rise of the cloud. The heating load was considerably effected by the ambient temperature regardless of the cloud cover. Besides, the temperature of hot water increased with the solar radiation. The COP of the heat pump was significantly influenced by the ambient temperature, that was 2.09~2.46 for gray day and 1.94~2.71 for fair day, respectively.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.21 no.12
• /
• pp.695-702
• /
• 2009

Dynamic behavior of Libr-water absorption system using low-temperature hot water was investigated numerically. Thermal-hydraulic model of single-effect/double-lift 100 RT chiller was developed by applying transient conservation equations of total mass, Libr mass, energy and momentum to each component. Transient variations of system properties and transport variables were analysed during start-up operation. Numerical analysis were performed to quantify the effects of bulk concentration and part-load operation on the system performance in terms of cooling capacity, coefficient of performance, and time constant of system. For an absorption chiller considered in the present study, optimum bulk concentration was found to exist, which resulted in the minimum time constant with stable cooling capacity. COP and time constant increased as the load decreased down to 40%, below which the time constant increased abruptly and COP decreased as the load decreased further.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.1037-1042
• /
• 2009

In connection with a recent research project dealing with heating system in apartment buildings by district heating, it was realised that in general very little information on the actual performance of heating and hot water systems in apartment buildings has been documented. In order to improve of district heating systems, a prediction of the heat demand first needs to be determined before a production plan. this is hot water heat system developed in this paper. this is also analyzed relation heat load with preheat load in hot water heating exchanger system.

• Journal of the Korean Solar Energy Society
• /
• v.32 no.6
• /
• pp.53-59
• /
• 2012

This study was carried out to evaluate thermal performance of the renewable hybrid heat supply system with solar thermal system and wood pellet boiler for Zero Carbon Green home of apartment houses. The hybrid heat supply system was set up at Korea Institute Energy Research in 2011. The system was comprised of the wood pellet boiler unit with heat capacity designed as 20,000kcal/hr, a $0.15m^3$ hot water storage tank for space heating, a evacuated tubular solar collector $3.74m^2$ of aperture area at the $20^{\circ}$ install angle, a $0.3m^3$ hot water storage tank. Thermal performance tests for one-house of apartment house were carried out by hot water load and heating load in winter season through the hybrid heat supply system. As a result, hot water energy supplied by the hybrid heat supply system was 11kWh in a day. Solar thermal energy portion was 2.99kWh which is 27% of the total hot water energy supply. wood pellet boiler supply portion was 8.017kWh which is 73% of the total hot water energy supply.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.34 no.11
• /
• pp.55-62
• /
• 2018

To receive financial support for the Green Remodeling, applicants must submit an energy simulation report. However, many of the applicants are not green remodeling specialist and energy simulation services are too expensive for them. For this reason, this study was to develop an energy simulation program to enhance green remodeling for the non-specialist such as housewives. Firstly, to enhance understanding and accessibility improvement energy simulation, simulation process was designed four steps and reducing input data. Specifically, input data was reduced by categorizing the following for the area, plan type, hot water load, electricity load, statistical inference. And then, to accurately verify the calculation result, the heat and hot water demand were derived and compared with ECO2 and Energy # program. Lastly, the calculation shows that there is a difference of 4% for the heat load and 15% to 33% for the hot water load respectively.

• Journal of the Korean Solar Energy Society
• /
• v.29 no.5
• /
• pp.1-7
• /
• 2009

Energy demands for offices in Korea are surveyed and analyzed to generate communicational models for simulations. Daily energy loads of 13 office buildings scattered in the 6 largest cities in the country are surveyed and analyzed based on energy consumption log sheets. Detailed hourly loads that are frequently required when a detailed operation simulation is performed are measured using remote data acquisition processes for 3 offices. The complete load demand models of electricity, cooling, heating and hot water are established by combining the daily and hourly patterns based on the statistical behavior of the hourly patterns.

• The KSFM Journal of Fluid Machinery
• /
• v.18 no.1
• /
• pp.29-36
• /
• 2015

Recently, Stirling engines are emerging as a key device for power conversion of renewable energy or waste energy. This study develops a LTDSE(Low Temperature Differential Stirling Engine) using a water spray for higher heat transfer and performs load performance tests for various flow rates and temperatures of hot water spray for variable engine loads emulated by a mechanical friction device. Internal temperature and pressure, working frequency and inlet and outlet temperature of the supply water are measured. As a result, the increases in flow rate and temperature of hot water respectively enhance the power output, efficiency and the working frequency, while the increasing engine load leads to decreases in working frequency but increases in the pressure amplitude. Eventually, it is revealed there exists a maximum shaft power of the test engine.

• Journal of Energy Engineering
• /
• v.21 no.4
• /
• pp.435-443
• /
• 2012

The combination of space shortage and the high population density concentrated in urban areas of South Korea has resulted in the growth of large-scale high-rise residential complexes, naturally affecting water and hot water usage patterns as well. But the current designs for water and hot water supply in South Korea rely mostly on international design standards and data calculated on site due to the severe shortage of basic data in relation to actual use, which result in the frequent problem of the under-or over-design of water and hot water supply. The following study measures the hot water supplier's conditions and the user's heat usage to realize the amount of time required for hot water supply load generation and the pattern of actual use in order to create basic data for effective hot water supply facility design and maintenance.

• Journal of the Korean Solar Energy Society
• /
• v.26 no.2
• /
• pp.103-109
• /
• 2006

The Purpose of this work is to investigate a long-term thermal performance of active solar hot water heating system for the dormitory of university. For this, monitering system including temperature sensors, flow-meters was installed in this system. Measurement was continued for 13 months between April 1st 2004 and May 31th 2005. As results, hot water demand, daily and monthly hot water load distribution which are necessary for the solar system design were suggested. Also thermal stratification in solar buffer tank was observed in the point of increasement of system efficiency. The yearly solar fraction and system efficiency of this system are about 29.5% and 44.9% respectively.