• Title/Summary/Keyword: Heat Load Simulation

Search Result 250, Processing Time 0.021 seconds

A Simulation Study on Effect Analysis of EMS Combined Control of Central Cooling and Heating System (중앙냉난방시스템의 EMS 복합제어 효과 분석에 관한 시뮬레이션 연구)

  • Jae-Yeob Song;Byung-Cheon Ahn
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
    • /
    • v.18 no.4
    • /
    • pp.33-44
    • /
    • 2022
  • In this study, we analyze the existing heating and cooling operation method for an office-type complex building with a central heating and cooling system, and examine the effects of applying various EMS that can be applied according to the load size to save energy in the building. For this purpose, simulation analysis was performed. As a control method, reset control of chilled water, hot water, cooling water and supply air temperatures, optimal start/stop of heat source, and number of heat source control were applied according to the load size, and energy consumption was analyzed accordingly. In addition, when all of these control methods were applied, the overlapping energy saving effect was finally confirmed. As a result, it was possible to confirm the energy saving effect when EMS for reset control and heat source control were applied compared to the existing control method of the heating and cooling system, and the effect for the case of using all these control methods in combination was also confirmed.

A Study on Performance Analysis of the Helically Coiled Evaporator with Circular Minichannels

  • Kim Ju-Won;Im Yong-Bin;Kim Jong-Soo
    • Journal of Mechanical Science and Technology
    • /
    • v.20 no.7
    • /
    • pp.1059-1067
    • /
    • 2006
  • In order to develop a compact evaporator, experiments that show characteristics of evaporating heat transfer and pressure drop in the helically coiled minichannel were performed in our previous research. This study was focused on the performance analysis of helically coiled heat exchangers with circular minichannels with an inner diameter=1.0 mm. The working fluid was R-22, and the properties of R-22 were estimated using the REFPROP program. Numerical simulation was performed to compare results with the experimental results of the helically coiled heat exchanger. As the heat transfer rate and pressure drop were calculated at the micro segment of the branch channels, the performance of the evaporator was evaluated. The following conclusions were obtained through the numerical simulations of the helically coiled heat exchanger. It showed good performance when the flow rate of each branch channels was suitable to heat load of air-side. The numerical simulation value agreed with experimental results within ${\pm}15%$. In this study, a numerical simulation program was developed to estimate the performance of a helically coiled evaporator. And, an optimum helically coiled minichannels evaporator was designed.

Investigation of the Thermal Performance of a Vertical Two-Phase Closed Thermosyphon as a Passive Cooling System for a Nuclear Reactor Spent Fuel Storage Pool

  • Kusuma, Mukhsinun Hadi;Putra, Nandy;Antariksawan, Anhar Riza;Susyadi, Susyadi;Imawan, Ficky Augusta
    • Nuclear Engineering and Technology
    • /
    • v.49 no.3
    • /
    • pp.476-483
    • /
    • 2017
  • The decay heat that is produced by nuclear reactor spent fuel must be cooled in a spent fuel storage pool. A wickless heat pipe or a vertical two-phase closed thermosyphon (TPCT) is used to remove this decay heat. The objective of this research is to investigate the thermal performance of a prototype model for a large-scale vertical TPCT as a passive cooling system for a nuclear research reactor spent fuel storage pool. An experimental investigation and numerical simulation using RELAP5/MOD 3.2 were used to investigate the TPCT thermal performance. The effects of the initial pressure, filling ratio, and heat load were analyzed. Demineralized water was used as the TPCT working fluid. The cooled water was circulated in the water jacket as a cooling system. The experimental results show that the best thermal performance was obtained at a thermal resistance of $0.22^{\circ}C/W$, the lowest initial pressure, a filling ratio of 60%, and a high evaporator heat load. The simulation model that was experimentally validated showed a pattern and trend line similar to those of the experiment and can be used to predict the heat transfer phenomena of TPCT with varying inputs.

A study on the saving of energy consumption load using electrical heat control system (전기적 열제어 시스템을 사용한 에너지 소비량 감소에 관한 연구)

  • Han, Kyu Il
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.49 no.1
    • /
    • pp.58-66
    • /
    • 2013
  • Most of steam power plant in Korea are heating the feed water system to prevent freezing water flowing in the pipe in winter time. The heating system is operated whenever the ambient temperature around the power plant area below 5 degree Centigrade. But this kind of heat supplying system cause a lot of energy consuming. If we think about the method that the temperature of the each pipe is controled by attaching the temperature measuring sensor like RTD sensor and heat is supplied only when the outer surface temperature of the pipe is under 5 degree Centigrade, then we can save a plenty of energy. In this study, the computer program package for simulation is used to compare the energy consumption load of both systems. Energy saving rate is calculated for the location of Youngweol area using the data of weather station in winter season, especially the January' severe weather data is analyzed for comparison. Various convection heat transfer coefficients for the ambient air and the flowing water inside the pipe was used for the accurate calculation. And also the various initial flowing water temperature was used for the system. Steady state analysis is done previously to approximate the result before the simulation. The result shows that the temperature control system using RTD sensor represents the high energy saving effect which is more than 90% of energy saving rate. Even in the severe January weather condition, the energy saving rate is almost 60%.

Development of Optimum Design Method for Geothermal Performance based on Energy Simulation (지열 성능해석 시뮬레이션에 기반한 최적 설계 수법 개발)

  • Moon, Hyeongjin;Kim, Hongkyo;Nam, Yujin
    • Journal of the Architectural Institute of Korea Structure & Construction
    • /
    • v.35 no.3
    • /
    • pp.43-48
    • /
    • 2019
  • Since the revision of the Rationalization of Energy Use Law, the spread of new and renewable energy in buildings has been promoted. In addition, the production of electric power and thermal energy is an important issue in the change of energy paradigm centered on the use of distributed energy. Among them, geothermal energy is attracting attention as a high-performance energy-saving technology capable of coping with heating / cooling and hot water load by utilizing the constant temperature zone of the earth. However, there is a disadvantage that the initial investment cost is high as a method of calculating the capacity of a geothermal facility by calculating the maximum load. The disadvantages of these disadvantages are that the geothermal energy supply is getting stagnant and the design of the geothermal system needs to be supplemented. In this study, optimization design of geothermal system was carried out using optimization tool. As a result of the optimization, the ground heat exchanger decreased by 30.8%, the capacity of the heat pump decreased by 7.7%, and the capacity of the heat storage tank decreased by about 40%. The simulation was performed by applying the optimized value to the program and confirmed that it corresponds to the load of the building. We also confirmed that all of the constraints used in the optimization design were satisfied. The initial investment cost of the optimized geothermal system is about 18.6% lower than the initial investment cost.

Analysis of Life Cycle Cost for Heat Source Equipments in Buildings for Adolescent Trainees (청소년 수련관의 열원설비 대안별 생애주기 비용에 관한 연구)

  • Ahn, Chang-hwan;Pang, Seung-ki;Baik, Yong-gyu
    • KIEAE Journal
    • /
    • v.5 no.3
    • /
    • pp.25-31
    • /
    • 2005
  • Computer simulations were performed for Heating Ventilating and Air-Conditioning (HVAC) systems to figure out more efficient maintenance methods for the building used for adolescent trainees. This study aims at suggesting design alternatives for optimum operation and performing life cycle cost (LCC) for each alternative. First, the capacity of the heat source equipment was determined using annual maximum heating and cooling loads. Annual loads were calculated and applied to the alternative for the purpose of calculating annual energy cost. Second, several types of data were collected to predict energy cost. Finally, the pay back period for each alternative was calculated using total cost estimation during standard duration period. This study indicates that the absorption chiller that does not occupy most part of a mechanical room, and does not need much operation cost was most economical.

Performance Characteristics of the Desiccant Cooling System in Various Outdoor and Load Conditions (외기조건에 따른 제습냉방시스템의 성능 특성)

  • Lee, Dae-Young;Chang, Young-Soo
    • Proceedings of the SAREK Conference
    • /
    • 2009.06a
    • /
    • pp.623-628
    • /
    • 2009
  • Desiccant based air conditioning system offers a promising alternative to conventional one using vapour compression refrigeration for energy saving and greenhouse gas reduction. It is a heat driven cycle which has high potential for the use of low grade heat source such as the waste heat from the cogeneration plant or the solar thermal energy. In this study, the cooling performance of a desiccant cooling system incorporating a regenerative evaporative cooler was characterized in various operation conditions through numerical simulation. The cooling capacity and COP were evaluated at various outdoor conditions, regeneration temperatures, and supply flow rates. Based on the performance characteristics, the optimal control scheme was discussed to minimize the cooling cost at part load condition.

  • PDF

Impact of Power System Interconnection to Embedded Generation and simulation (분산전원의 전력계통연계에 따른 영향 및 시뮬레이션)

  • Park, Jee-Woong;Kim, Jong-Hyung;Shin, Myong-Chul
    • Proceedings of the KIEE Conference
    • /
    • 2002.11b
    • /
    • pp.280-282
    • /
    • 2002
  • As EG(Embedded Generation : photo-voltaic, wind, combined heat and power, fuel cell, small hydro etc.) grows fast in adopting to peak load reducing at the middle or the end of distribution system, there much has been interested in interconnection of EG. This paper discusses the various issue of a embedded generator to power system and shows the simulation of its various situation that could happen (focusing on load-flow by EG) by using a commercial software CYME(PSAF) for load-flow. With a result of above simulation, this paper shows a way of possible solution briefly.

  • PDF

Analysis of Thermodynamic Design Data for Heating of Double - Effect Solar Absorption System using LiBr - water and Ethylene Glycol Mixture (에틸렌글리콜 혼합액을 사용하고, 태양열을 보조열원으로 하는 이중효용 흡수식 시스템의 난방 특성해석)

  • Won, S.H.
    • Journal of the Korean Solar Energy Society
    • /
    • v.22 no.4
    • /
    • pp.51-61
    • /
    • 2002
  • Analysis of thermodynamic design data of double effect solar absorption heat pump system for heating has been done to find the property of Libr-water + ethylene Glycol mixture for working fluid by computer simulation. Derived thermodynamic design data. enthalpy based coefficient of performance and flow ratio for possible combinations of operating temperature for water - LiBr and Ethylene Glycol mixture (H2O: CHO ratio 10:1 by mole) by computer simulation. The obtained results, COP and mass flow ratio of the water-lithium bromide-ethylene glycol system, are compared with data for the water-Libr pair solution.

A Study on the High Efficiency Ground Source Heat Pump System (1) (부하추종형 고효율 지열히트펌프 시스템에 관한 연구 (1))

  • Koh, Deuk-Yong;Kim, Ook-Joong;Choi, Sang-Kyu;Chang, Ki-Chang
    • New & Renewable Energy
    • /
    • v.1 no.4 s.4
    • /
    • pp.30-37
    • /
    • 2005
  • Cycle simulation of Ground Source Heat Pump[GSHP] system was carried out to determine the design specification of basic components such as turbo compressor and heat exchangers. Part load operation characteristics of the designed GSHP system was estimated using the compressor and heat exchanger performance data. A 50RT class turbo compressor for GSHP system is now under development, in which R134a refrigerant is adopted as working fluid. The compressor with variable cascade diffusers is designed to work both in cooling and heating modes so that it can actively keep up with the climate change with high efficiency. The normal running speeds of the compressor are 59000rpm for heating mode and 70000rpm for tooling mode respectively. It has two identical impellers at both ends of the rotor so as to minimize aero-induced thrust force effectively. GSHP system was coupled with a vortical type heat exchanger, and heat gain and heat loss from ground were evaluated per a bore hole. For the optimal integration of the heat pump system, its header for circulating fluid was combined with the ground heat exchangers in parallel and series configuration.

  • PDF