Heat Charging Characteristics of 42MJ_th Scale Thermal Energy Storage System using Organic Phase Change Materials

( Dong-ju Kim ),( Dong-kyoo Park ),( Bup-mook Jeong ),( Jae-hoi Gu ),( Dong-cheol Kim ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-

Due to the increase in fuel and power generation costs worldwide, there is growing interest in the use of waste heat from nonrecycling industry. The waste heat recovery market is expected to grow at a CAGR of 6.74% from 2017 to 2021. Low temperature waste heat of less than 300 ℃ generated in power plants and industries is mostly being abandoned due to economical efficiency and lack of demand. And the waste heat utilization rate of domestic industrial waste treatment companies is only 38 %. Organic Rankine cycle power generation, thermoelectric power generation, and thermal energy storage system based on phase change materials or chemical storage heat are attracting attention as measures for increasing the utilization rate of low-grade waste heat. Thermal energy storage technology has been developed and applied mainly in USA, Germany and Japan, but it has not yet been put into practical use in Korea. In this study, a 42MJth scale Thermal Energy Storage(TES) system was developed. The thermal storage characteristics of organic phase change materials such as internal temperature distribution, heat charging/discharging rate and heat transfer time and efficiency were studied using TES system. The phase change temperature of the organic phase change material used was 68 ~ 71 ℃ and low pressure steam and air were used as heat transfer medium for heat charging and discharging. Most of the waste heat generated by the industry is discharged in the form of steam, it is possible to use waste heat without using extra heat exchanger. This work was supported by the Energy Efficiency & Resources of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20162010104620)

원자력 발전소 온배수 이용 농산물에 대한 소비자 인식조사

허승욱 한국유기농업학회 2018 韓國有機農業學會誌 Vol.26 No.3

This study examines consumers’ perception of agricultural products using nuclear power plants waste heat. This study surveyed 348 consumers and found that presenting information about safety of waste heat utilization increased appropriacy of waste heat; after providing the information, the percentage of respondents in favor of using waste heat increased 27.5% point from 38.3% to 65.8%. The most important reason against using waste heat was because it threatened the safety of agricultural products, and the most important reason for its support was to reduce farm production costs. The purchase intention for agricultural products using waste heat had risen by at least 10% point after providing the information about safety of waste heat. Those means that it important provision of accurate and reliable information on the safety of waste heat to encourage the utilization of waste heat from nuclear power plants. Purchase intention for flowers using waste heat was most, followed by vegetables, fruits (including fruits and vegetables).

4세대 지역 냉난방을 위한 폐열 회수 및 활용에 대한 기존 논문 검토

장재혁(Jae Hyuck Chang),이호성(Hoseong Lee) 대한설비공학회 2020 대한설비공학회 학술발표대회논문집 Vol.2020 No.6

In this study, the potential of waste heat in the previous studies is reviewed. Based on this, all possible applicable waste heat recovery technologies for 4<SUP>th</SUP> generation district heating and cooling are classified. There has been research on the potential of waste heat by industry and country. Currently, research on waste heat recovery is actively studied in various applications. Waste heat was classified into waste heat utilization which is used for electricity, heat, and cooling, and waste heat storage used for storing waste heat. The use of waste heat recovery technologies for district heating and cooling will have advantages in terms of environment and economy.

Heating performance characteristics of a dual source heat pump using air and waste heat in electric vehicles

Ahn, J.H.,Kang, H.,Lee, H.S.,Jung, H.W.,Baek, C.,Kim, Y. Applied Science Publishers 2014 APPLIED ENERGY Vol.119 No.-

A heat pump has been considered as an alternative to an electric heater to increase the efficiency of the heating unit in electric vehicles. However, the heating performance of a single source heat pump has yet to be improved at low outdoor temperatures. This study investigates the feasibility of a dual source heat pump using both air and waste heat in electric vehicles. The performance of the dual source heat pump was measured at various operation modes: air source-only, waste heat-only and dual heat source. The heating performance of the dual source heat pump was higher than those of the single source heat pumps. In addition, an alternating single mode operation of air source-only and waste heat-only modes was proposed to improve performance at low outdoor air temperatures.

다단압축 중간주입을 통한 폐열회수 히트펌프 시스템 연구

이상욱(Sangwook Lee),김귀택(Gwitaek Kim),정융(Yoong Chung),김민수(Min Soo Kim) 대한설비공학회 2020 대한설비공학회 학술발표대회논문집 Vol.2020 No.6

This study suggest a multi-level heat pump system with vapor injection using waste heat recovery. Electric vehicle (EV) cannot obtain waste heat from power generation system like internal combustion engine. Therefore, EV needs extra heat from heat pump or positive tempeature coefficient heater (PTC) in winter for cabing heating. These auxiliary devices consume power from battery, resulting in reduction of driving range. And this phenomenon cause a fear called ‘Range anxiety’, which is a major obstacle from purchasing EV. To solve this problem, this study suggests a vapor injection system using waste heat from electric devices, including motor and battery. General waste heat recovery system in EV absorbs heat at the evaporator. However, large temperature difference between refrigerant and waste heat recovery system entails low heat exchange efficiency and high irreversibility. Suggested mid-level waste heat recovery can recover heat more efficiently. The performance of this heat pump system is investigated with numerical model. Results shows improvement in heating capacity, consequently coefficient of performance and driving range.

선박메인엔진 냉각수를 활용한 선박폐열발전-담수화 시스템 성능평가 시뮬레이션

임승택,김현주,문정현,이호생 한국마린엔지니어링학회 2019 한국마린엔지니어링학회지 Vol.43 No.9

The demand for high efficiency vessels is increasing due to the problems of international marine environments and rising ship oil prices. As a result, research on power generation methods that utilize waste heat from ships has begun. In this study, organic Rankine cycle (ORC)-based waste heat power is designed using engine cooling water of a 58MW ship and is compared through simulation with the desalination capacity of a desalination plant that uses cooling water of 80 °C passed through a waste heat power. The power output and heat transfer performance are assessed by applying various refrigerants to select the working fluid for ship waste heat recovery, and then the performances of new refrigerants are compared to identify one with a low global warming potential. The study also compared the output of a ship waste heat recovery system with generated waste heat discharged to the sea by applying various types of engine types and cooling water flow rates. The power output and thermal power are compared when engine coolant is supplied at temperatures of 80 °C, 85 °C, and 90 °C. Finally, the optimal operating conditions of the ship waste heat–desalination system are determined by comparing the evaporation temperature and fresh water production rate based on the evaporation pressure of the ship desalination plant. The waste heat recovery–desalination system using a 90 °C heat source from the 10S90ME 58MW ship confirmed a pure water output of 564.4 kW and fresh water production of 1.278 kg/s when the R245fa working fluid was applied, and a reduction of 35%. 국제적 해양 환경문제와 선박유의 가격상승으로 고효율 선박의 수요가 증가하고 있으며, 선박에서 발생하는 폐열을 활용한 발전 방식의 연구가 진행되고 있다. 본 연구에서는 58MW급 선박의 엔진 냉각수를 활용하여 ORC를 기반으로한 폐열발전을 시뮬레이션을 통해 설계하였으며, 폐열발전을 통과한 80℃의 냉각수를 활용한 담수화 설비의 담수생산량을 비교하였다. 선박폐열발전의 작동유체의 선정을 위한 다양한 냉매를 적용하여 발전출력과 열전달 성능을 비교하였으며, 저 GWP 냉매를 적용하기 위하여 신냉매의 성능을 비교하였다. 다양한 선종의 엔진타입과 냉각수 유량을 적용하여선박폐열발전의 출력과 바다로 배출되는 폐열 발생을 비교하였으며, 엔진 냉각수 온도가 80℃, 85℃, 90℃로 공급될 때발전 출력과 페열량을 비교하였다. 또한, 선박 담수화 설비의 증발압력의 변화에 따른 담수 생산량과 증발 온도를 비교하여 선박폐열발전-담수화 시스템의 최적 운전조건을 도출하였다. 10S90ME의 58MW급 선박의 90℃ 열원을 활용한 폐열발전-담수화 시스템은 R245fa 작동유체를 적용하여 564.4kW의 순수 발전출력과 1.278kg/s의 담수생산량을 확인하였으며, 기존 폐열 발생량 대비 35%의 감소량을 확인하였다.

Thermal Analysis of Cylindrical Model of Waste Form Containing High Heat-generating Nuclides Using Analytical and Numerical Methods

Jong Kwang Lee,Jung-Hoon Choi,Byeonggwan Lee,Hwan-Seo Park 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

The fabrication of waste forms with high thermal and structural stability is an essential technology for the safe management and disposal of radioactive wastes. In particular, the thermal characteristics of waste forms containing high heat-generating nuclides such as Cs and Sr can be used for the optimized design of the waste form to secure its thermal safety, and they also provide basic design data for the safe management of canisters, storage systems, and repositories. The Korea Atomic Energy Research Institute is actively developing processes and equipment for fabricating various types of high-level wastes into a stable glass or ceramic waste form. In previous research related to the thermal analysis of the waste form, a relatively simple analysis was performed by using the analytic solution of the one-dimensional steady-state heat conduction equation considering the decay heat properties of the waste. As a specific application study, the optimized diameter of the cylindrical glass waste form was proposed by evaluating the centerline temperature of the waste form. In this study, we extended previous research by introducing a more complicated model, and the main results are summarized as follows. First, an analytical solution was derived by applying the temperaturedependent thermal conductivity expressed in the general form of polynomial function to the onedimensional heat conduction problem previously studied. Second, the two-dimensional axisymmetric steady-state heat conduction problem with a more realistic cylinder model with finite length was modeled and solved by using the finite element method via Matlab’s PDE (partial differential equation) toolbox. Third, thermal analysis was performed on the SrTiO3 waste form, selected as a stable form of strontium nuclide, using the developed analytical and numerical methods. The differences in the temperature distribution and computation time were evaluated through a comparative study of both solutions. Although the problem considered in this study could easily be solved by using commercial CFD software such as ANSYS or SolidWorks, a code-based program was developed to facilitate parametric design study in conjunction with optimization algorithms. The analysis results could be used to evaluate the thermal stability of waste form and to optimize the shape and size of the waste form in consideration of the design constraints of storage systems or repositories.

스팀헤더 운전조건 변경에 따른 소각 폐열 회수 효율성 비교

정구황,현재혁,최경훈,윤주영,서승덕,채상협 한국폐기물자원순환학회 2015 한국폐기물자원순환학회지 Vol.32 No.4

Recently, many countries have been interested in waste-to-energy policy and technology due to the economic crisis from high oil price and the demands on securing the sustainable energy sources. As one of the efforts to achieve the sustainable society and maintain low impact of global warming in Korea, the act on the promotion of saving and recycling resources was enacted to implemetnt the effective reduction of waste at source level, reduce, recycling and recovery of waste to energy. Attaining an efficient recovery of waste heat in a cogeneration plant from incineration facilities is important as a resource recovery of waste to energy. In this study, the waste heat recoveries changed by reducing feed pressure in incineration conditions were analyzed. As results, changing the operating condition in steam header resulted in stable heat supply and increase of waste heat recovery.

사업장간 폐열이동용 배관건설 및 이를 열원으로 이용한 흡수식냉동기 적용에 의한 온실가스 저감사례

최동규(Dong Kyoo Choi),도양희(Yang Hee Do),김해봉(Hae Bong Kim),인성범(Seong Bum In) 대한설비공학회 2022 대한설비공학회 학술발표대회논문집 Vol.2022 No.11

This study aimed to make the solution that the industries do not recover the waste heat because of its low temperature. Industries like the chemical plant have the process in higher temperature comparing the temperature of waste heat. Main purpose of transporting the heat from one site to the other site is to use waste heat effectively. The pilot project has been done by constructing the piping to move waste heat between two sites and installing the absorption chiller to use waste heat transported in the other site. The site supplying heat can make a profit by selling waste heat and the other site also save the cost by using cheaper chilled water. Feasibility study also has been done to show the reduction of green house gas.

Design of a Pure Paraffin Separating Machine From Concentrated Waste Solidified With Paraffin by Using Heating Vaporization and Pressure Difference

Tae-Yang Noh,Byeong-Mok Park,Cheol-Wan Park,Ah-Ran Cha,Sang-Hwan Jun,Seong-Won Baek 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

In domestic nuclear power plants, drums of concentrated radioactive waste solidified with paraffin that do not meet radioactive waste disposal standards are stored temporarily. In this paper, the design of a machine that separates these paraffin drums into paraffin and concentrated waste using heating vaporization and pressure difference is described. The separation process is as follows. First, the paraffin solid is indirectly heated by heating the outside of the drum. The paraffin solid is partially melted to increase the fluidity and is easily detached from the drum. The detached solid is transferred to the melting tank, and further heated in the melting tank. When the temperature is sufficiently high, paraffin is melted and becomes a mixture of liquid paraffin and concentrated waste homogeneously. The mixed solution is transferred to a paraffin recovery vessel and further heated. The vaporization point of paraffin is 370°C under atmospheric pressure, and becomes lower depending on the pressure decreasing in the vessel. The vaporization point of the paraffin is a relatively low value compared to the radioactive elements in the concentrated waste, and therefore only paraffin would be vaporized. A paraffin transfer pipe is installed on the upper part of the paraffin recovery vessel, and is connected to another tank called the paraffin capture vessel. The pressure of the paraffin capture vessel is reduced (i.e. vacuum condition), only gaseous paraffin is transferred to the paraffin capture vessel by the pressure difference. When the paraffin capture vessel is cooled below the vaporization point of the paraffin, the paraffin is liquefied or solidified, and only the paraffin is recovered. Based on the above process, the solidified paraffin could be separated into pure paraffin and concentrated waste. However, if a radioactive element with a lower vaporization point than paraffin exists in the concentrated waste, it may be mixed with paraffin and separated together. Therefore, it is necessary to measure the radioactivity or radiation dose rate for the separated paraffin, and to verify that it is sufficiently low. If necessary, additional separation process may be considered for removing radioisotopes from the paraffin.