scholarly journals Improving Comfort and Air Conditioner Performance by Optimizing Controllers under Actual Usage Conditions

2021 ◽  
Vol 11 (11) ◽  
pp. 4818
Author(s):  
Taebyoung Park ◽  
Byungsoon Kim ◽  
Gilun Hwang ◽  
Yulho Kang ◽  
Inwon Lee ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Control Method ◽  
Pressure Control ◽  
Load Estimation ◽  
Cooling Load ◽  
Air Conditioner ◽  
Actual Usage ◽  
Target Pressure ◽  
The Difference

This study is to increase the efficiency of the air conditioning system under actual conditions of use. In order to improve the increase in energy consumption due to control without considering indoor cooling load fluctuations, we review it compared to conventional control methods in two respects. First, we examined the control method to reduce energy consumption by varying the evaporative pressure of the system according to the cooling load, and secondly, further reducing energy consumption by controlling the revolutions per minute (RPM) of the fan of the indoor unit at the same time as the pressure fluctuation under the cooling load. We found that changing the target pressure depending on the difference between the target temperature and room temperature can control temperature more efficiently and save energy than using fixed target pressure, and that the effect increases when applying the control of the air volume of the indoor air. Cleaning up the resulting values, the fan-load-control condition of the cooling-load-estimation control method showed an energy savings effect of 16.1%–48.7% compared with the fixed-pressure control method and 1.2%–37.7% compared with the cooling-load-estimation control method.

scholarly journals Assessment of vehicle brake control functional stability

2021 ◽  
Vol 12 (2) ◽  
pp. 33-44
Author(s):  
Volodymyr Volkov ◽  
◽  
Igor Gritsuk ◽  
Tetiana Volkova ◽  
Volodymyr Kuzhel ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Control Method ◽  
Operating Conditions ◽  
National Standards ◽  
Passenger Vehicles ◽  
The Difference ◽  
Braking Control ◽  
The Stability ◽  
Friction Surfaces

The article is devoted to the study of the influence of the brake control elements of passenger vehicles on the stability of their braking properties. The analysis of the influence of uneven braking forces on the wheels of one axle of vehicles on the deviation of the distribution of braking forces between the axles from its calculated value is carried out. When assessing the error in regulating the distribution of braking forces between the axles of vehicles, three components were taken into account: the theoretical error due to the imperfection of the selected control method (the difference between the actual calculated control characteristic from the ideal), the error created due to the instability of the ratio of the braking forces on the front and rear wheels, an additional error caused by the unevenness of the braking forces on the wheels of individual axles, since the fulfillment of the most stringent requirements of international and national standards for the efficiency of braking of vehicles and is inextricably linked with the need to increase the energy consumption of brake mechanisms. The energy consumption of braking mechanisms is understood as the ability of the latter to dissipate the greatest amount of energy of the braking machine without reducing the braking efficiency indicators to the minimum permissible level. Excessive heating of the braking mechanisms leads to a decrease in the friction coefficient μ of the friction surfaces and increased wear of the friction linings, and the brakes are the most unstable element of the braking control, which ensures the absorption and dissipation of the vehicle's energy during braking. The instability of the braking torques on the front and rear wheels, caused by a change in the coefficients of friction of friction pairs, leads not only to a change in the distribution of braking forces between the axles and individual wheels, but also to a decrease in the braking efficiency of vehicles under operating conditions. A method is proposed that makes it possible to assess the quality of regulation of the distribution of braking forces between the axles of a car, taking into account the instability of the braking forces on the wheels.

scholarly journals Systematic Simplified Simulation Methodology for Deep Energy Retrofitting Towards Nze Targets Using Life Cycle Energy Assessment

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3038 ◽  
Author(s):  
José Sánchez Ramos ◽  
MCarmen Guerrero Delgado ◽  
Servando Álvarez Domínguez ◽  
José Luis Molina Félix ◽  
Francisco José Sánchez de la Flor ◽  
...  
Keyword(s):  
Life Cycle ◽  
Energy Consumption ◽  
Energy Savings ◽  
Residential Building ◽  
Energy Performance ◽  
Simulation Tools ◽  
Energy Assessment ◽  
Energy Efficiency Improvement ◽  
The Difference ◽  
Reduction Of Energy Consumption

The reduction of energy consumption in the residential sector presents substantial potential through the implementation of energy efficiency improvement measures. Current trends involve the use of simulation tools which obtain the buildings’ energy performance to support the development of possible solutions to help reduce energy consumption. However, simulation tools demand considerable amounts of data regarding the buildings’ geometry, construction, and frequency of use. Additionally, the measured values tend to be different from the estimated values obtained with the use of energy simulation programs, an issue known as the ‘performance gap’. The proposed methodology provides a solution for both of the aforementioned problems, since the amount of data needed is considerably reduced and the results are calibrated using measured values. This new approach allows to find an optimal retrofitting project by life cycle energy assessment, in terms of cost and energy savings, for individual buildings as well as several blocks of buildings. Furthermore, the potential for implementation of the methodology is proven by obtaining a comprehensive energy rehabilitation plan for a residential building. The developed methodology provides highly accurate estimates of energy savings, directly linked to the buildings’ real energy needs, reducing the difference between the consumption measured and the predictions.

Optimization of Equipment Control Parameters to Minimize HVAC Energy Consumption

2011 ◽  
Author(s):  
Aaron P. Wemhoff
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Control Method ◽  
The United States ◽  
Lumped Parameter Model ◽  
Base Case ◽  
Control Parameters ◽  
Household Energy ◽  
Lumped Parameter ◽  
Air Conditioning Systems

Heating, Ventilating, and Air Conditioning Systems (HVAC) consume nearly one-third of household energy in the United States. The optimization of the control parameters in HVAC equipment allows for a reduction in energy consumption. In this study, a supervisory control method is applied to a lumped parameter model of an HVAC system of interest containing a chiller and three dampers. The method determines the choice of control parameters that minimize the energy consumption for 1000 sampled steady-state loads. An energy savings of 39% was achieved using the method in this study compared to the base case.

scholarly journals Alternativa energética sustentable mediante la utilización de aislantes térmicos de diferentes materiales en edificaciones con sistemas de aire acondicionado

2020 ◽  
pp. 1-8
Author(s):  
Edzel Jair Casados-López ◽  
Alvaro Casados-Sánchez ◽  
Raúl Cruz-Vicencio ◽  
Alvaro Horst-Sánche
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Energy Savings ◽  
Cooling Load ◽  
Test Models ◽  
Scale Models ◽  
Conditioning Equipment ◽  
Actual Energy Consumption ◽  
Reduction Of Co2 ◽  
The City

A methodology is proposed for calculating the cooling load and the energy consumption of air conditioning equipment in three scale models of buildings under study, using the ASHRAE CLTD / SCL / CLF method. The building in which the mentioned method is used are three scale models of buildings located in the city of Poza Rica, state of Veracruz, Mexico. This method is applied in order to obtain the cooling load as exact as possible and thus avoid oversizing in air conditioning equipment, and by using thermal insulation, achieve a decrease in energy consumption and thus contribute to the reduction of CO2 emissions, to energy saving and therefore to sustainable development. The cooling load is calculated by applying the proposed methodology to three cases: model A, B and C. The results for the three test models, object of this study, are compared. Measurements of energy consumption are made to perform the error analysis of the actual energy consumption with respect to that calculated using the method. Finally, energy savings are quantified, in the cases mentioned.

Research on the Active Pressurization Control Method of RBS

2014 ◽  
Vol 644-650 ◽  
pp. 4864-4868
Author(s):  
Liang Chu ◽  
Yi Yang ◽  
Chong Guo ◽  
Yu Ting Huang ◽  
Wen Hui Li
Keyword(s):  
Control Method ◽  
Modulation Frequency ◽  
Pulse Signal ◽  
Pressure Control ◽  
Ratio Method ◽  
Regenerative Braking ◽  
Duty Ratio ◽  
Braking System ◽  
Pressurization Rate ◽  
Target Pressure

This paper based on the regenerative braking system, which developed in the '863' project, designed pressure control method for RBS system in the condition of active pressurization state and conduct Bench experiments. The results show that, under the condition of high frequency, through modulation frequency of the pulse signal and duty ratio method can coordinate the regenerative braking and hydraulic braking force, meet target pressure and the pressurization rate requirements of RBS.

scholarly journals The Pressure Control of High-Pressure Tubing Based on Difference Equation

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yang Zhang ◽  
Rongjun Li ◽  
Linhai Zou
Keyword(s):  
High Pressure ◽  
Difference Equation ◽  
Fuel Injection ◽  
Control Method ◽  
Pressure Control ◽  
Needle Valve ◽  
Oil Pump ◽  
Pressure Tubing ◽  
The Difference ◽  
The One

The situation where fuel enters and exits the high-pressure tubing is one of the important factors that affect the working efficiency of the engine. Based on the simplified high-pressure tubing model, this paper studies the control problems of high-pressure tubing injection and fuel supply under certain circumstances. According to the idea of the difference equation, the paper obtains the opening time of the one-way valve when the pressure value of the high-pressure tubing is kept constant or rises to a specific value by enumerating the opening time of the one-way valve. By establishing the physical model of the high-pressure tubing and the fuel injection nozzle, and then using the enumeration method, the angular velocity of the high-pressure oil pump cam when the pressure of the high-pressure fuel pipe is kept constant can be obtained. Under the more complicated injector model, the control method of the injector is solved by the double enumeration method. The results show that the above model can quickly calculate the optimal working time of the high-pressure fuel pump and needle valve when the accuracy meets the requirements.

scholarly journals Improving Building Energy Performance Using Dual VAV Configuration Integrated with Dedicated Outdoor Air System

Buildings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 466
Author(s):  
Nabil Nassif ◽  
Iffat Ridwana
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Energy Savings ◽  
Energy Performance ◽  
Office Building ◽  
Effective Control ◽  
Cooling Load ◽  
Outdoor Air ◽  
System A ◽  
Cooling Loads

As building systems account for almost half of the total energy consumed by the building sector to provide space heating, cooling, and ventilation, efficiently designing these systems can be the key to energy conservation in buildings. Dual VAV systems with an effective control strategy can substantially reduce the energy consumption in buildings, providing a significant scope of further research on this system configuration. This paper proposes to utilize the warm air duct of the dual VAV system as a dedicated outdoor air (DOA) unit when no heating is required, which allows the cooling load to be effectively distributed between two ducts. A specific control sequence is proposed with different supply air temperature reset strategies to estimate the heating, cooling loads, and fan power energy consumption of the proposed system. A simple two-zone office building is taken as a preliminary case study to simulate the airflow rates and fan power of a single duct VAV and proposed dual VAV systems to illustrate the concept. Finally, a larger multi-zone office building is simulated to measure the annual heating, cooling loads, and fan power energy and compare the energy savings among the systems. The results show significant fan power reduction ranging from 1.7 to 9% and notable heating energy reduction up to 76.5% with a small amount of cooling load reduction varying from 0.76 to 2.56% depending on the different locations for the proposed dual VAV systems. Further energy savings from different supply air temperature reset strategies demonstrate the opportunity of employing them according to climates and case studies. The proposed dual VAV system proves to have the potential to be adapted in buildings for the purpose of sustainability and energy savings.

scholarly journals Techno-Economic Assessment of an Air-Multiple PCM Active Storage Unit for Free Cooling Application

2021 ◽  
Vol 13 (23) ◽  
pp. 12936
Author(s):  
Muriel Iten
Keyword(s):  
Energy Consumption ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Economic Assessment ◽  
Environmental Benefits ◽  
Office Building ◽  
Cooling Load ◽  
Storage Unit ◽  
Air Channels ◽  
Maintenance Requirements

A latent energy storage (LES) unit is presented in this paper for free space cooling and ventilation application. The unit includes multiple phase change materials (PCM) to advance the thermal performance of common LES units. It is composed by metallic rectangular panels containing commercial paraffins with melting temperatures ranging among 20 °C and 25 °C and surrounded by air channels. The average cooling load of the unit corresponds to approximately 1 kW over 8 h. It fulfils the peak ventilation cooling load during summer of an office building in Portugal. The study provides a techno-economic analysis and the environmental benefits of the LES technology compared to a traditional air conditioning (AC) unit for the cooling and ventilation of an office building. During daytime, the air-multiple PCM unit allows reducing the energy consumption by nearly 200 kWh. The full charging of the PMs during nighttime, requires significant energy consumption due to the high air flowrate demand for full solidification. The competitiveness of such units can be achieved by introducing fins into the panels, allowing double the energy savings. In an overall perspective, the unit presents several benefits such as lower initial cost and reduced maintenance requirements (non-use of refrigerants and batteries) that also allows better personal health issues when related to traditional ACs.

The Temperature Control Based on the AHU of Fuzzy-PID

2013 ◽  
Vol 427-429 ◽  
pp. 537-540
Author(s):  
Xiang Dong Wang ◽  
Xin Wang ◽  
Jing Liang Wei ◽  
Shu Jiang Li
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Control Method ◽  
Air Conditioner ◽  
Fuzzy Pid ◽  
Control Effect ◽  
Fuzzy Pid Control ◽  
General Control ◽  
Input Quantity ◽  
Central Air Conditioning

Air conditioner unit which is a significant part of central air-conditioning is a multiinput-multioutput system.Because the input quantity of it is related with each other and influenced by multifarious interference, an ideal control effect is unavailable by general control method. It is also the main unit of energy consumption, so the refrigeration effect and the energy consumption of the central air-conditioning are determined by the control effect and efficiency of it. A neural network model is made according to the unit of air handing and controlled by the strategy of fuzzy-PID. It is proved by experiment that favorable control effect is available in case that the fuzzy-PID control strategy meets requirements when either there is interference or the target quantity changes.

scholarly journals Electric Air Conditioning Control Method of Electric Bus Based on Driving Conditions

2018 ◽  
Vol 232 ◽  
pp. 04011
Author(s):  
Yong Luo ◽  
Li-fu Li ◽  
Yan-ping Tan
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Control Method ◽  
State Of Charge ◽  
Cooling Load ◽  
Electric Bus ◽  
Driving Conditions ◽  
Avl Cruise ◽  
The Relationship ◽  
Conditioning Control

For reducing energy consumption of electric air conditioning (E-A/C) in electric bus, an E-A/C control method based on driving conditions (including the temperature of bus compartment, the number of passengers, the state of charge (SOC) of battery) is proposed. Firstly, the relationship between E-A/C cooling load and driving conditions is theoretically researched, then an E-A/C control method by dynamically adjusting compartment temperature is proposed. Secondly, an E-A/C model and a bus model are established and simulated in AVL Cruise and MATLAB, the results indicate that the proposed control method can reduce the energy consumption of E-A/C significantly, and effectively improve electric bus performance.

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