An analysis of stochastic properties of room temperature, cooling load and air-conditioning systems

1993 ◽  
Vol 28 (4) ◽  
pp. 497-508 ◽  
Author(s):  
Shuichi Hokoi ◽  
Mamoru Matsumoto
Keyword(s):  
Air Conditioning ◽  
Room Temperature ◽  
Cooling Load ◽  
Air Conditioning Systems ◽  
Stochastic Properties

Simulation Research About Air Conditioning Load Calculation

2012 ◽  
Vol 433-440 ◽  
pp. 6023-6027
Author(s):  
Hui Fan Zheng ◽  
Ting Ting Xiao
Keyword(s):  
Air Conditioning ◽  
Cooling Load ◽  
Theory Analysis ◽  
Simulation Research ◽  
New Period ◽  
Simulation Calculation ◽  
Load Calculation ◽  
Calculation Point ◽  
History Of ◽  
Air Conditioning Systems

Theory analysis method is adopted in this paper to review the development history of air-conditioning loads calculation, point out that the air-conditioning loads calculation went through from steady calculation to periodic unsteady calculation and then to new period of dynamic load calculation. Simulation calculation of air-conditioning cooling load have been developed deeply, and many software can be used to calculate the hourly cooling load about building. At last, The application of neutral network for prediction of cooling load in air conditioning systems have been introduced.

scholarly journals Support Vector Regression and Genetic Algorithm for HVAC Optimal Operation

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Ching-Wei Chen ◽  
Yung-Chung Chang
Keyword(s):  
Genetic Algorithm ◽  
Power Consumption ◽  
Air Conditioning ◽  
Support Vector ◽  
Operating Parameters ◽  
Cooling Load ◽  
Unit Load ◽  
Air Handling Unit ◽  
Consumption Model ◽  
Air Conditioning Systems

This study covers records of various parameters affecting the power consumption of air-conditioning systems. Using the Support Vector Machine (SVM), the chiller power consumption model, secondary chilled water pump power consumption model, air handling unit fan power consumption model, and air handling unit load model were established. In addition, it was found thatR2of the models all reached 0.998, and the training time was far shorter than that of the neural network. Through genetic programming, a combination of operating parameters with the least power consumption of air conditioning operation was searched. Moreover, the air handling unit load in line with the air conditioning cooling load was predicted. The experimental results show that for the combination of operating parameters with the least power consumption in line with the cooling load obtained through genetic algorithm search, the power consumption of the air conditioning systems under said combination of operating parameters was reduced by 22% compared to the fixed operating parameters, thus indicating significant energy efficiency.

scholarly journals Experimental Investigation of a Split Air Conditioning Using Condensate as Direct Evaporative Cooling

2021 ◽  
Vol 86 (1) ◽  
pp. 140-153
Author(s):  
Azridjal Aziz ◽  
Muhammad Rif’at Syahnan ◽  
Afdhal Kurniawan Mainil ◽  
Rahmat Iman Mainil
Keyword(s):  
Air Conditioning ◽  
Evaporative Cooling ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Air Conditioner ◽  
Direct Evaporative Cooling ◽  
Compressor Power ◽  
Discharge Pressure ◽  
Air Conditioning Systems

Split air conditioning systems produce reasonable amount of condensate which is usually not utilized and thrown away to the environment. On the other hand, it consumes a lot of energy during operation. The aim of this study is to investigate the improvement of air conditioning systems performance utilizing condensate. A direct evaporative cooling using condensate is incorporated on a 0.74 ton-cooling capacity of split air conditioning to decrease the air temperature before entering the condenser. Performances of the split air conditioning with and without direct evaporative cooling are compared and presented in this paper. The results show that the use of direct evaporative cooling using condensate into the air before passing through the condenser reduces the compressor discharge pressure. The decrease of the condenser pressure led to 4.7% and 7% reduction of power consumption for air conditioner without cooling load and air conditioner with 2000 W cooling load, respectively. The cooling effect and coefficient of performance (COP) increase with the decrease of compressor power. The use of direct evaporative cooling with condensate into the air before entering the condensing system can enhance the system performance and protect the environment.

scholarly journals Air conditioning predictive control for rail transit vehicles based on load prediction

2020 ◽  
Vol 165 ◽  
pp. 04071
Author(s):  
Yichen Zhao ◽  
Haiquan Bi ◽  
Honglin Wang
Keyword(s):  
Feedback Control ◽  
Energy Saving ◽  
Predictive Control ◽  
Air Conditioning ◽  
Room Temperature ◽  
Control Method ◽  
Air Cooling ◽  
Load Prediction ◽  
Dynamic Correction ◽  
Air Conditioning Systems

This paper proposes a predictive control method for rail vehicle air-conditioning systems. Due to heat transfer and diffusion, the air-conditioning system is a long-time-delay system. However, most air-conditioning systems use feedback control, which has problems such as long transition time, system shock, and mismatch between air cooling capacity and load, resulting in the waste of energy. Combined with feedforward and feedback control, a predictive control method with dynamic correction is proposed to solve this problem. Based on the load prediction, the real-time indoor temperature feedback link is added to send the cold air into the room in advance, which makes the room temperature stable, and the energy-saving effect significant. In the study, variance analysis of environmental factors is performed to improve the accuracy of the load prediction system, and the mean relative error (MRE) of the prediction reached 0.0112. By comparing the simulation results of predictive control and feedback control, it is proved that the predictive control with correction has a smoother room temperature curve. The energy-saving rate is about 25.2%.

Retrofitting R-22 Split Type Air Conditioning with Hydrocarbon (HCR-22) Refrigerant

2013 ◽  
Vol 388 ◽  
pp. 91-95 ◽  
Author(s):  
Henry Nasution ◽  
Abdul Latiff Zulkarnain ◽  
Azhar Abdul Aziz ◽  
Mohd Rozi Mohd Perang
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Room Temperature ◽  
Internal Heat ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Refrigeration System ◽  
Electrical Energy Consumption ◽  
The One

An experimental study to evaluate the energy consumption of a split type air conditioning is presented. The compressor works with the fluids R-22 and HCR-22 and has been tested varying the internal heat load 0, 500, 700 and 1000 W. The measurements taken during the one hour experimental periods at 10-minutes interval times for temperature setpoint of 20oC. The performance data considered where the evaporator cooling load, the condenser heat rejection, the electrical energy consumption, the refrigeration system temperatures, and the room temperature. And hence the Coefficient of Performance (COP) could be determined. The final results of this study show an overall better energy consumption of the HFC-22 compared with the R-22.

scholarly journals Effects of Time to Unactuate Air Conditioning on Fire Growth

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3100
Author(s):  
Teng-Yi Wang ◽  
Kuang-Chung Tsai
Keyword(s):  
Air Conditioning ◽  
Room Temperature ◽  
Heat Radiation ◽  
Air Conditioner ◽  
Fire Growth ◽  
Fire Dynamics ◽  
Air Inlet ◽  
Air Supply ◽  
Fire Safety Design ◽  
Air Conditioning Systems

Air conditioning systems have become essential equipment in many buildings. However, fire safety design and management in buildings rarely consider whether to turn the system off or keep it on in a fire. This study ignites a stack of wood in a room center or corner to explore the influence of air inlet actions of a fan coil unit (FCU) with the door opened or closed. Simulation results using Fire Dynamics Simulator (FDS) demonstrate that the heat release rate (HRR) and room temperature obviously decrease when the room doorway is closed, regardless of whether the air conditioner is turned on. The air supply for combustion is poor. When the door of the room is opened, turning off the air conditioner can effectively reduce the HRR and the room temperature in the early stages of fire growth. However, along with the fire growth, turning on air conditioning can help decrease the heat radiation feedback and the consequent HRR. Therefore, the conclusion that air conditioning always enhances a fire because it provides oxygen may not always be correct.

scholarly journals Comparison of cooling load and air conditioning systems in a lecture hall located in Poland and Spain

2018 ◽  
Vol 44 ◽  
pp. 00081
Author(s):  
Dorota Anna Krawczyk ◽  
Bernadetta Wądołowska ◽  
Antonio Rodero
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Lecture Hall ◽  
Cooling Load ◽  
Heat Sources ◽  
Air Conditioning System ◽  
Air Infiltration ◽  
Electrical Devices ◽  
Air Conditioning Systems ◽  
North And South

This paper discusses issues related to cooling load and energy consumption for air conditioning systems and presents the results of calculations conducted for six different climate localizations: three in Poland (Bialystok, Warsaw, Wroclaw) and three in Spain (Burgos, Madrid, Cordoba). Analysis was conducted for a same lecture hall design for 100 users locates in the different cities. During cooling load calculations, we focused on gains from diverse type of heat sources: electrical devices, air infiltration, heat transfer trough envelope and occupants. Calculations were made for a comfort temperature that was set at 22°C in Poland and 24°C in Spain following previous studies [11]. The highest contributions to cooling load correspond to occupancy and solar gains which depends mainly on outdoor conditions. In Poland, cooling load was found similar for different locations, while in Spain, they are big differences between cities located in North and South of this country by effect of different outdoor conditions. The work also compares cost of air condition annual energy consumption costs for the air conditioning system. Highest cost for cooling was found in Spain (Cordoba) with value (2629 €) almost 378% higher than average Polish cost.

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