• Journal of Climate Change Research
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• v.6 no.2
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• pp.73-85
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• 2015

With 12 environmental basic facilities (EBF) in Busan, each business place's present situation of the operation of new and renewable energy as well as the feasibility to establish additional systems of utilizing solar energy (photovoltaic power generation system [PPGS] and solar heating system [SHS]) were investigated. Currently, with the environmental basic facilities, the new and renewable energies (such as, waste heat, biogas, PPGS, SHS, and small hydro power) can produce 195 GWh per year as electric power unit. Among the energy sources, except waste heat, biogas (154 GWh/yr) appears as the highest. Next, PPGS is the second most widely used system and produces 5,560 MWh/yr at 11 business places. Through a field survey, it appears that 19 business places of total 27 places at 12 EBFs have good locational conditions and they need an introduction of PPGS. Through it, it is investigated that it would be possible to produce 5,311 MWh/yr and to reduce $2,348tCO_2/yr$. And, it is identified that SHS can be additionally introduced in only 4 EBFs. This can reduce energy cost as much as one ten million won/yr and green-house gas as much as $28tCO_2/yr$. A cost-benefic analysis shows that the use of governmental support or private investment can be the most efficient way, when PPGS and SHS are introduced in EBFs.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.04a
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• pp.1-4
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• 1999

본 연구에서는 시설원예용 하우스의 난방방식별 온열환경특성 즉, 온도 분포상의 문제점을 파악하고, 하우스 난방시스템 선정 및 하우스 설계를 위한 기초자료를 제공하기 위하여 동일 부지에 동일한 형상으로 조성된 단동 하우스에 각각 심야전력 전기히터, 경유 보일러에 의한 온풍난방, 무가온 상태로 설정하여 하우스내 온열환경에 관한 분포특성을 검토하였다. (중략)

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.43-47
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• 2000

Two modes of shock waves, a compression shock wave and a thermal shock wave, propagating in He II have been investigated. The shock waves are at a time generated by the impingement of a gasdynamic shock wave onto a He II free surface in the newly developed superfluid shock tube facility. Superconductive temperature sensors, piezo-type pressure transducers and visualization photograph were used for the measurement of them and the phenomena induced by them were investigated in detail. It is found that the compression by a compression shock wave in He II causes temperature drop because He II has negative thermal expansion coefficient. the thermal shock wave is found to be of a single triangular waveform with a limited shock strength. The waveform is similar to that generated by stepwise strong heating from an electrical heater for relatively long heating time. In the experiments at the temperatures near the lambda temperature, no thermal shock wave is sometimes detected in shock compressed He II. It can be understood that shock compression makes He Ii convert to He I in which no thermal shock wave is excited.

• Advances in Automotive Engineering
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• v.1 no.1
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• pp.79-104
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• 2018

A detailed literature review is presented for the applications of the heat pump technologies on the electric vehicles Heating, Ventilation and Air Conditioning (HVAC) system. Due to legal regulations, automotive manufacturers have to produce more efficient and low carbon emission vehicles. Electric vehicles can be provided these requirements but the battery technologies and energy managements systems are still developing considering battery life and vehicle range. On the other hand, energy consumption for HVAC units has an important role on the energy management of these vehicles. Moreover, the energy requirement of HVAC processes for different environmental conditions are significantly affect the total energy consumption of these vehicles. For the heating process, the coolant of internal combustion (IC) engine can be utilized but in electric vehicles, we have not got any adequate waste heat source for this process. The heat pump technology is one of the alternative choices for the industry due to having high coefficient of performance (COP), but these systems have some disadvantages which can be improved with the other technologies. In this study, a literature review is performed considering alternative refrigerants, performance characteristics of different heat pump systems for electric vehicles and thermal management systems of electric vehicles.

• Journal of Biosystems Engineering
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• v.32 no.2 s.121
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• pp.102-108
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• 2007

Heat pump systems are recognized to be heating and cooing systems. In this study, to check the practical application possibility of heat pump systems as low temperature storage systems and get basic data, apples of a long term storage items were stored and performance of low temperature storage and quality changes of apples were evaluated. Cooling coefficient of performance of the system was from 1.1 to 1.3. Although ambient air temperature varied widely from $-13^{\circ}C$ to $29.6^{\circ}C$ during low temperature storage period from January to June, the average temperature of low temperature storage chamber was $1.1^{\circ}C$ at setting temperature of $1.5^{\circ}C$. Sucrose of apples stored by the heat pump decreased from initial sucrose of 15.4% (Brix number) to final sucrose of 14.3%. Weight loss ratio of apples was 9.7% and internal and external view of apples after low temperature storage were very satisfactory with the naked eye.

• Solar Energy
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• v.8 no.1
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• pp.57-67
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• 1988

The task, development of the exemplary patterns for the application of passive solar systems in residential buildings, is very crucial regarding government policies toward energy conservation. So various measurements, evaluation, and feasibility studies are performed in addition to their architectural design and detailed drawings. In conclusion, passive solar systems are effective and economical when they are applied to residential buildings for heating systems.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.3
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• pp.43-48
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• 2008

The economics of a passive solar heating system (PSHS) with the pebble bed heat storage was evaluated, and the applications of the PSHS were analyzed, in this study. The results are as follows: The heating load, solar heat gain, and stored heat/year of the PSHS in the solar house model were found to be 10,778MJ, 3,438MJ, and 11,682MJ, respectively. The yearly energy expenses of the PSHS and the alternative heating system (conventional coal heating system, CCHS), which uses coal, were found to be USD 1.60/year and USD 60.90/year, respectively, and the yearly expenses of the PSHS were found to be 38 times less than those of the alternative heating system (CCHS). If it will be supposed that the life cycle of the passive solar heating system, according to the results of the LCC analysis in the two systems, is 40 years, the total expenses for the life cycle of the PSHS and the CCHS will be USD 1,431.50 and USD 2,740.00, respectively. The period for the investment payback of the PSHS is six years.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.6
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• pp.45-52
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• 2009

This study was conducted in the process that the basic plan of the formation of the thermal energy complex in the Iwon reclaimed land of Taean was being made. Targeting for the large-sized greenhouse to be made in this area, it examined the cooling and heating load and the amount of ventilation, and also analyzed the economic efficiency of heating. The research results are as per the below: The minimum ambient temperature of this area was measured on January 7, 2001, which was $-18.7^{\circ}C$, and the maximum ambient temperature of this area was measured on July 24, 1994, which was $36.7^{\circ}C$. The maximum heating load was 39,011 MJ/h, but the date when the maximum heating load was not consistent with the date when the minimum temperature was measured. The maximum cooling load was 88,562MJ/h, It was approximately 2.3 times of the maximum heating load, which was measured at 14:00 hours on September 4, 2000. The maximum amount of ventilation heat was 138,639MJ/h. Assuming the rate of solar heat use as 10%, 20%, 50%, and 100%, the total sum of cost-benefit would be ￦-193,450,000, ￦-634,930,000, ￦-3,372,960,000, and ￦-9,850,420,000, respectively 20 years later. The break-even point of the geothermal heat pump would be about 4 years for 10% use, about 3 years for 20% or 50% use, and approximately 6 years for 100% use. It was found that 50% use would be most advantageous. In case two systems are combined, the break-even point will be 10 years, 8 years, and 11 years respectively.

• Journal of the Korean Solar Energy Society
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• v.22 no.3
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• pp.1-10
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• 2002

Relatively being economical in installation and easy in operation, hot-air heating system has been generally used in greenhouse for heating system regardless of high cost in maintenance and uneven distribution of air temperature. Therefore to overcome the disadvantages in maintenance and in distribution of air temperature and to improve efficiency of heating system, this experimental study is performed. This experimental study aims to improve the character of uneven temperature distribution in vertical direction and to reduce energy consumption for heating in a greenhouse. The experiment had been performed to investigate change of thermal environment and effects on reducing energy consumption for heating in greenhouse by additional surface insulation and reduction of indoor-air volume that come by installing transparent vinyl membranes with different height in each house. The results show that there is a wide difference in oil-energy consumption between houses according to condition of surface insulation and change of indoor-air volume. Furthermore, the results show that the efficiency of dual surface is higher than that of change of indoor-air volume in terms of energy saving.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.379-384
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• 2000

In order to use the natural thermal energy as much as possible for greenhouse heating, the air-air heat pump system involved PCM(phase change material) latent heat storage system was composed, and three types of greenhouse heating system(greenhouse system, greenhouse-PCM latent heat storage system, greenhouse-PCM latent heat storage-heat pump system) were recomposed from the greenhouse heating units to analyze the heating characteristics. The results could be concluded as follows; 1) In the greenhouse heated by the heat pump under the solar radiation of 406.39W/$m^2$, the maximum PCM temperature in the latent heat storage system was 24$^{\circ}C$ and the accumulated thermal energy stored in PCM mass of 816kg during the daytime was 100,320kJ. In the greenhouse without heat pump under the maximum solar radiation of 452.83W/$m^2$, the maximum PCM temperature in the latent heat storage system was 22$^{\circ}C$ and the accumulated thermal energy stored during the daytime was 52.250kJ. 2) In the greenhouse-PCM system without heat pump the heat stored in soil layers from the surface to 30cm of the soil depth was 450㎉/$m^2$. 3) In all of the greenhouse heating systems, the difference between the air temperature in greenhouse and the ambient temperature was about 20~23$^{\circ}C$ in the daytime. In the greenhouse without heat pump and PCM latent heat storage system the difference between the ambient temperature and the air temperature in the greenhouse was about 6~7$^{\circ}C$ in the nighttime, in the greenhouse with only PCM latent heat storage system the temperature difference about 7~13$^{\circ}C$ in the nighttime and in the greenhouse with the heat pump and PCM latent heat storage system about 9~14$^{\circ}C$ in the nighttime.