Development of a non-stationary thermal environment analysis method for combined convection and radiation air conditioning

2021 ◽  
pp. 108559
Author(s):  
Tatsuhiro Yamamoto ◽  
Akihito Ozaki ◽  
Myongyang Lee ◽  
Keigo Aratsu ◽  
Ryo Fukui
Keyword(s):  
Air Conditioning ◽  
Thermal Environment ◽  
Analysis Method ◽  
Environment Analysis ◽  
Combined Convection

scholarly journals Optimal Air Conditioner Placement Using a Simple Thermal Environment Analysis Method for Continuous Large Spaces with Predominant Advection

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4663
Author(s):  
Tatsuhiro Yamamoto ◽  
Akihito Ozaki ◽  
Myonghyang Lee
Keyword(s):  
Air Conditioning ◽  
Thermal Environment ◽  
Fluid Dynamic ◽  
Optimal Placement ◽  
Air Conditioner ◽  
Analysis Method ◽  
Computational Fluid Dynamic Analysis ◽  
Environment Analysis ◽  
Air Conditioners ◽  
Energy Simulations

The number of houses with large, continuous spaces has increased recently. With improvements in insulation performance, it has become possible to efficiently air condition such spaces using a single air conditioner. However, the air conditioning efficiency depends on the placement of the air conditioner. The only way to determine the optimal placement of such air conditioners is to conduct an experiment or use computational fluid dynamic analysis. However, because the analysis is performed over a limited period, it is difficult to consider non-stationarity effects without using an energy simulation. Therefore, in this study, energy simulations and computational fluid dynamics analyses were coupled to develop a thermal environment analysis method that considers non-stationarity effects, and various air conditioner arrangements were investigated to demonstrate the applicability of the proposed method. The accuracy verification results generally followed the experimental results. A case study was conducted using the calculated boundary conditions, and the results showed that the placement of two air conditioners in the target experimental house could provide sufficient air conditioning during both winter and summer. Our results suggest that this method can be used to conduct preliminary studies if the necessary data are available during design or if an experimental house is used.

Application Study of Load Forecasting of Central Air-Conditioning System Based on Time Sequence Analysis Method

2012 ◽  
Vol 220-223 ◽  
pp. 622-625
Author(s):  
Xue Li Zhu ◽  
Bo Dong ◽  
Yong Jun Zhu
Keyword(s):  
Sequence Analysis ◽  
Air Conditioning ◽  
Time Lag ◽  
Load Forecasting ◽  
Time Sequence ◽  
Analysis Method ◽  
Air Conditioning System ◽  
Central Air Conditioning ◽  
Heating Load ◽  
Time Sequence Analysis

With the characteristics of non-stationarity, non-linearity, time-lag of refrigeration/ heating supplying in minds, load forecasting of central air-conditioning system is carried using time sequence analysis method. Firstly, acquisition sample data of central air-conditioning system is pretreated, and random time sequence AR model of system is formulated. Then, forecasting of AR refrigeration/heating load based on Yule-walker method is conducted. In order to enhance forecasting accuracy, crossover forecasting is introduced into the load forecasting, that is, to use vertical forecasting to follow household demands for load and horizontal forecasting to track changes of weather. Then, weight cross is made to vertical and horizontal forecasting results. Finally, refrigeration/heating load forecasting software of central air-conditioning system is developed, which is used in energy-saving monitoring and control of central air-conditioning system.

scholarly journals Thermal Environment Analysis for Preserving Ancient Mural Painting in Songsan-ri Tomb No. 6, Gongju, Korea

2016 ◽  
Vol 32 (4) ◽  
pp. 521-534 ◽  
Author(s):  
Dae Woon Kim ◽  
Sun Hye Jeong ◽  
Min Young Lee ◽  
Yong Jae Chung
Keyword(s):  
Thermal Environment ◽  
Mural Painting ◽  
Environment Analysis

Analysis of the influence of cooling jets on the wind and thermal environment in football stadiums in hot climates

2019 ◽  
Vol 41 (5) ◽  
pp. 561-585 ◽  
Author(s):  
Fangliang Zhong ◽  
John K Calautit ◽  
Ben R Hughes
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Optimized Design ◽  
Outdoor Temperature ◽  
World Cup ◽  
Wind Environment ◽  
The Spectator

After winning the bid of the FIFA’s World Cup 2022, Qatar is facing the greatest challenges in terms of minimizing substantial energy consumptions for air-conditioning of stadiums and maintaining aero-thermal comfort for both players and spectators inside stadiums. This paper presents the results of temperature distributions and wind environment of the original stadium under the hot-humid climate and improvements on them for optimized scenarios of cooling jets. A combined computational fluid dynamics and building energy simulation approach was used to analyse the cooling performance and energy consumption per match of cooling air jets for 10 scenarios with different supply velocities, supply temperatures and locations of jets. The optimal scenario is to employ vertical jets above the upper tiers at supply temperature of 20°C and velocities of 2–12 m/s, integrated with horizontal jets of the same temperature at the lower tiers with 4 m/s and around the pitch with 7 m/s. This scenario can maintain the spectator tiers at an average temperature of 22°C and reduce the maximum predicted percentage of dissatisfied of thermal comfort from the original 100% to 63% for the pitch and 19% for the tiers, respectively. In terms of the energy consumption for the air-conditioning system per match, compared with one of the 2010 South Africa World Cup stadiums Royal Bafokeng stadium which consumed approximately 22.8 MWh energy for air-conditioning in winter (highest outdoor temperature 24.4°C), the maximum energy consumption of the optimal scenario in November (highest outdoor temperature 34.2°C) can reach 108 MWh. In addition, the spectator zones with scenario 8 have the potential to be resilient to the seasonal change of outdoor temperature if slight modifications of the supply velocities and precise temperature control on the spectator zones are applied. Moreover, the configurations presented in this paper can be used as a foundation of jets arrangement for future stadium retrofits in the hot climates. Practical application: This study assesses the aero-thermal conditions of a case study stadium under the hot climate of Qatar and explores the potential of applying cooling jets with different supply velocities, supply temperatures and their locations on the enhancement of both thermal and wind environment of spectator tiers and pitch. The assessment of the original stadium indicates that the ascending curved roof structure impedes the fresh air entering into the stadium and results in an asymmetric temperature distribution on the spectator tiers. The optimized design suggests a combination of vertical jets under the roof and both three arrays of horizontal jets at lower tiers and around pitch for future stadium optimizations in hot climates. It also recommends enhancing the thermal conditions on the pitch by optimizing the velocity of horizontal jets around the pitch. Moreover, the future design of the exact stadiums to be resilient to the seasonal changing outdoor temperature can be implemented based on scenario 8.

Optimal Operational Planning of Cogeneration Systems With Microturbine and Desiccant Air-Conditioning Units

2004 ◽  
Author(s):  
Satoshi Gamou ◽  
Koichi Ito ◽  
Ryohei Yokoyama
Keyword(s):  
Energy Flow ◽  
Energy Demand ◽  
Air Conditioning ◽  
Optimization Problem ◽  
Energy Charge ◽  
Ambient Air ◽  
Operational Planning ◽  
Optimization Approach ◽  
Analysis Method ◽  
Air Humidity

Economic and energy-saving characteristics of cogeneration systems with microturbine and desiccant air-conditioning units are investigated on system operational planning. An optimization approach is adopted to rationally evaluate these characteristics. In this approach, on/off and rated/part load status of operation of equipment and energy flow rates are determined so as to minimize the hourly energy charge subject to satisfaction of energy demand requirements. In this optimization problem, performance characteristics of the microturbine and desiccant air-conditioning units are modeled in consideration of the influence due to ambient air temperature. Moreover, the influence due to ambient air humidity is also considered in the desiccant air-conditioning unit using the psychrometric diagram. The implementation of the numerical analysis method, discussed in this paper, to two cogeneration systems, clearly shows economic and operational benefits of using desiccant air-conditioning.

scholarly journals Simulation and experimental study of phase change cooling and heating wall radiation air conditioning system

2020 ◽  
Vol 143 ◽  
pp. 02044
Author(s):  
Gao Chunxue ◽  
Wu Songlin ◽  
Lang Junqian ◽  
Liu Qiuxin
Keyword(s):  
Phase Change ◽  
Thermal Performance ◽  
Air Conditioning ◽  
Field Experiments ◽  
Thermal Environment ◽  
Operating Conditions ◽  
Operation Condition ◽  
Heating Wall ◽  
Air Conditioning System ◽  
Winter Operation

This paper presents a case study of phase change cooling and heating wall radiant (PC-CHWR) air conditioning system application in an energy-saving renovation project in a laboratory in Wuhan, Hubei province in China. To test the thermal performance of the system, the PHOENICS software was utilized to simulate and analyse the indoor thermal environment in the laboratory under both winter and summer operating conditions. In addition, field experiments were also conducted under winter operation condition. By comparing the results between numerical simulation and field experiment, it is found that thermal performance of the PC-CHWR air conditioning system evaluated by these two evaluation methods are quite match. Moreover, the results also show that the PC-CHWR system can meet the cooling and heating load of the building within the acceptable range.

Sign in / Sign up

Export Citation Format

Share Document