Journal articles on the topic 'Air conditioning – Efficiency – Simulation methods'
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1
Wang, Jun, and Hai Xia Wang. "Air Flow in Large Space Building with CFD Model and Local Test." Advanced Materials Research 213 (February 2011): 260–66. http://dx.doi.org/10.4028/www.scientific.net/amr.213.260.
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Simulation with CFD and local test are two main methods in study on air flow in large space building. This paper tests and simulates thermal comfort and air distribution of existing air- conditioning mode of some exhibition center. Through comparison and analysis on existing and simulated air-conditioning pattern, draw a conclusion that it’s feasible to simulate thermal comfort and air distribution of air-conditioning. And the research is important to guide energy efficiency and design optimization of air-conditioning system in large space building.
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Ayaz, Murat, Volkan Aygül, Ferhat Düzenli˙, and Erkutay Tasdemi˙rci˙. "Comparative Study on Control Methods for Air Conditioning of Industrial Paint Booths." Advanced Science, Engineering and Medicine 11, no. 11 (November 1, 2019): 1053–59. http://dx.doi.org/10.1166/asem.2019.2454.
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It is of great importance that each product in industrial production facilities is to be produced in the same quality and standard. Especially in the automotive industry, the painting process needs to be done under certain environmental conditions according to the paint properties used. Therefore, the temperature, humidity and air quality values of the paint booth are very important for a quality painting operation. In this study, adaptive control has been proposed to control of one-zone heating-ventilation system for the paint booths. The system has been modelled by using the Matlab/Simulink. Performance of the proposed control method has been compared with conventional control methods such as On/Off, PID, fuzzy logic in terms of accuracy, efficiency and response time. Simulation results show that the proposed adaptive control is effective in the Heating, Ventilating, and Air Conditioning (HVAC) systems temperature control applications. In addition, energy efficiency in HVAC systems has been provided with the proposed control model. Furthermore, thermal analysis of the system has been done to corroborate simulation results.
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Kim, Younghyeon, Seokyeon Im, and Jaeyoung Han. "A Study on the Application Possibility of the Vehicle Air Conditioning System Using Vortex Tube." Energies 13, no. 19 (October 8, 2020): 5227. http://dx.doi.org/10.3390/en13195227.
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Since refrigerants applied to vehicle air conditioning systems exacerbate global warming, many studies have been conducted to supplement them. However, most studies have attempted to maximize the efficiency and minimize the environmental impact of the refrigerant, and thus, an air conditioning system without refrigerant is required. The vortex tube is a temperature separation system capable of separating air at low and high temperatures using compressed air. When applied to an air conditioning system, it is possible to construct an eco-friendly system that does not use a refrigerant. In this paper, various temperature changes and characteristics of a vortex tube were identified and applied to an air conditioning system simulation device. Additionally, an air conditioning system simulation device using indirect heat exchange and direct heat exchange methods was constructed to test the low-temperature air flow rate (yc), according to the temperature and pressure. As a result of the experiment, the temperature of the indirect heat exchange method was found to be higher than the direct heat exchange method, but the direct heat exchange method had low flow resistance. As a result, the direct heat exchange method can easily control the temperature according to the pressure and the low-temperature air flow rate (yc). Therefore, it was judged that the direct heat exchange method is more feasible for use in air conditioning systems than the indirect heat exchange method.
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Ni, Jing, Bowen Jin, Shanglei Ning, and Xiaowei Wang. "The Numerical Simulation of the Airflow Distribution and Energy Efficiency in Data Centers with Three Types of Aisle Layout." Sustainability 11, no. 18 (September 10, 2019): 4937. http://dx.doi.org/10.3390/su11184937.
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The energy consumption of fast-growing data centers is drawing attentions from not only energy organizations and institutions all over the world, but also charity groups, such as Greenpeace, and research shows that the power consumption of air conditioning makes up a large proportion of the electricity cost in data centers. Therefore, more detailed investigations of air conditioning power consumption are warranted. Three types of airflow distributions with different aisle layouts (the open aisle, the closed cold aisle, and the closed hot aisle) were investigated with Computational Fluid Dynamics (CFD) methods in a typical data center of four rows of racks in this study. To evaluate the results of thermal and bypass phenomenon, the temperature increase index (β) and the energy utilization index (ηr) were used. The simulations show that there is a better trend of the β index and ηr index both closed cold aisle and closed hot aisle compared with free open aisle. Especially with high air flow rate, the β index decreases and the ηr index increases considerably. Moreover, the results prove the closed aisles (both closed cold aisle and closed hot aisle) can not only significantly improve the airflow distribution, but also reduce the mixture of cold and heat flow, and therefore improve energy efficiency. In addition, it proves the design of the closed aisles can meet the increasing density of installations and our simulation method could evaluate the cooling capacity easily.
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Zhang, Dapeng, and Zhiwei Gao. "Improvement of Refrigeration Efficiency by Combining Reinforcement Learning with a Coarse Model." Processes 7, no. 12 (December 17, 2019): 967. http://dx.doi.org/10.3390/pr7120967.
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It is paramount to improve operational conversion efficiency in air-conditioning refrigeration. It is noticed that control efficiency for model-based methods highly relies on the accuracy of the mechanism model, and data-driven methods would face challenges using the limited collected data to identify the information beyond. In this study, a hybrid novel approach is presented, which is to integrate a data-driven method with a coarse model. Specifically, reinforcement learning is used to exploit/explore the conversion efficiency of the refrigeration, and a coarse model is utilized to evaluate the reward, by which the requirement of the model accuracy is reduced and the model information is better used. The proposed approach is implemented based on a hierarchical control strategy which is divided into a process level and a loop level. The simulation of a test bed shows the proposed approach can achieve better conversion efficiency of refrigeration than the conventional methods.
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Zhang, Dongxu, Kailiang Huang, Guohui Feng, Xue Lv, and Jintian Xu. "Study on fresh air load characteristics and energy saving measures of low energy consumption buildings in severe cold area." E3S Web of Conferences 356 (2022): 01059. http://dx.doi.org/10.1051/e3sconf/202235601059.
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In order to study the fresh air load characteristics of low energy consumption buildings with different envelope structure parameters, combined with the law of fresh air load, energy saving measures were studied. Taking the ultra-low energy consumption building of Shenyang Jianzhu University as an example, the DeST simulation software was used to establish five groups of models with different envelope structure parameters for load simulation. The simulation results show that the fresh air heat load in model 1 to model 5 is 29.89%, 34.66%, 38.60%, 44.68% and 53.36% of the building heat load, respectively. The seasonal fresh air cooling load of air conditioning accounted for 13.78%, 13.85%, 13.88%, 13.99% and 14.05% of the building cooling load respectively. The thermal insulation performance of the envelope has great influence on the thermal load of the building, but little influence on the cooling load of the building. The better the insulation performance of building envelope, the greater the energy saving potential of fresh air load. Fresh air heat load is sensible heat load, and fresh air cooling load is mainly latent cooling load. From the theoretical point of view, the building adopts a heat recovery device with a heat recovery efficiency of 0.6, which can save 5989.91kW • h in the heating season and reduce the building heat load by 32.02%. In the air conditioning season sensible heat recovery device can save energy 131.45kW • h, reduce building cooling load by 1.56%; Total heat recovery device can save energy of 708.73kW • h and reduce cooling load of building by 8.43%.With the development of zero-energy building technology, the requirement of fresh air energy consumption is more strict, and the active all-heat fresh air heat recovery device is more suitable for this building. It also has more space for future development. This paper analyzes the change of energy saving potential of fresh air with the development of building envelope. The methods and ideas of reducing energy consumption of fresh air in low energy consumption buildings are discussed.
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Wang, Shiqiang, Jianchun Xing, Ziyan Jiang, and Juelong Li. "A decentralized sensor fault detection and self-repair method for HVAC systems." Building Services Engineering Research and Technology 39, no. 6 (May 7, 2018): 667–78. http://dx.doi.org/10.1177/0143624418775881.
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This study proposes a novel decentralized sensor fault detection and self-repair method for heating, ventilation and air-conditioning systems. From the perspective of network structure, sensor fault diagnosis in heating, ventilation and air-conditioning systems is distributed to the updated smart sensors without the monitoring host, which is necessary in the traditional centralized method. A fully distributed flat sensor network is established based on fundamental physical equations. Similar to the structure, mechanism and characteristics of biological communities, a smart sensor needs only to communicate with adjacent nodes and operate collaboratively to complete sensor fault detection and self-repair tasks. These tasks are formulated as a constrained optimization and are solved by a decentralized algorithm with a penalty function executed in all the sensor nodes in parallel. The diagnosis model introduces an exponential function method to determine the precise location and undertake self-repair of a fault node. Simulation results on a chilled water system illustrate the effectiveness of the proposed method. Practical application: The traditional sensor fault detection and diagnosis methods for heating, ventilation and air-conditioning systems are based on a centralized structure with several deficiencies, such as high maintenance and labor costs, link congestion and operational lag. This study presents a decentralized sensor network structure and exponential-function-based method that possess the advantages of plug-and-play, rapid deployment, high flexibility and convenience for engineering implementation without having to build a central monitor. The efficiency and effectiveness of the proposed method are demonstrated via a case study.
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Yan, Liangwen, Fengfeng Qian, and Wei Li. "Research on Key Parameters Operation Range of Central Air Conditioning Based on Binary K-Means and Apriori Algorithm." Energies 12, no. 1 (December 29, 2018): 102. http://dx.doi.org/10.3390/en12010102.
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As the energy-saving control of central air conditioning has been widely applied in modern architecture, research of real-time optimal control based on historical data and identification of its optimal control strategies are of great importance for reducing energy wasting of buildings. However, due to the property of easily falling into local optimum, conventional k-means approach cannot achieve the goal of real-time optimal control, we therefore propose an innovative binary k-means clustering algorithm which is used to adjust the target value of temperature difference (TD) in the control system of chilled water and cooling water of central air conditioning system (CACS). Thanks to the clustering control, among the 304 test data, the coefficient of performance (COP) of 211 sets of data, which accounted for 69.41%, are higher than those of the traditional control method. In the simulation system, the COP of 191 sets of data, which accounted for 62.83%, are higher than those of traditional control methods, achieving better energy efficiency. To achieve the goal of identify potential energy-saving control strategies, the Apriori algorithm is proposed to correlate the key parameters and energy consumption efficiency of the CACS. The results show when the chilled water temperature difference (CWTD) > 2.0 °C and the cooling water temperature difference (COWTD) > 2.4 °C, some rules are discovered as follows: 1. The probability of a larger system COP will increase if the CWTD is set lower than the third quartile value or the COWTD is set lower than the first quartile value. 2. The probability of a larger system COP will also increase if the CTWD is set lower than the first quartile and the COWTD is set between the first and the third quartile. These underlying regularity is useful for technicians to adjust the control parameters of the equipment, to improve energy efficiency and to reduce energy consumption.
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Zhao, Fei, Xiaowei Li, and Jiangli Hou. "Simulation and Multi-Objective Optimization of the Vehicle Thermal Management System of Electric Cars." International Journal of Heat and Technology 39, no. 3 (June 30, 2021): 969–78. http://dx.doi.org/10.18280/ijht.390334.
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The research on the vehicle thermal management (VTM) system is very important for ensuring the driving reliability of electric cars, however, currently there’re few research concerned about this topic, and the existing ones mostly focus on matching and optimizing parameters to improve the management of driving kinetic energy, and the heat dissipation and cooling performance of the cars; however, there isn’t a uniform standard for evaluating these performances, and the research on closed thermal energy management and control based on the evaluation results is pending. This paper studied the simulation and multi-objective optimization of the VTM system of electric cars, and proposed accurate methods and ideas for evaluating the heat dissipation efficiency of the engine cooling system, the cooling efficiency of the air conditioning system, and the thermal management performance of the VTM of electric cars. Based on the model predictive control (MPC) algorithm of vehicle motion control, this paper constructed temperature control optimization objective functions for electric cars under various thermal adaptation working conditions such as low-speed slope climbing, medium-speed gentle slope climbing, high-speed driving, and idling; and it designed several strategies for the coordinated control of the VTM system of electric cars. At last, this paper used test results to verify the effectiveness of the proposed strategies.
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Parzinger, Michael, Lucia Hanfstaengl, Ferdinand Sigg, Uli Spindler, Ulrich Wellisch, and Markus Wirnsberger. "Residual Analysis of Predictive Modelling Data for Automated Fault Detection in Building’s Heating, Ventilation and Air Conditioning Systems." Sustainability 12, no. 17 (August 20, 2020): 6758. http://dx.doi.org/10.3390/su12176758.
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Faults in Heating, Ventilation and Air Conditioning (HVAC) systems affect the energy efficiency of buildings. To date, there rarely exist methods to detect and diagnose faults during the operation of buildings that are both cost-effective and sufficient accurate. This study presents a method that uses artificial intelligence to automate the detection of faults in HVAC systems. The automated fault detection is based on a residual analysis of the predicted total heating power and the actual total heating power using an algorithm that aims to find an optimal decision rule for the determination of faults. The data for this study was provided by a detailed simulation of a residential case study house. A machine learning model and an ARX model predict the building operation. The model for fault detection is trained on a fault-free data set and then tested with a faulty operation. The algorithm for an optimal decision rule uses various statistical tests of residual properties such as the Sign Test, the Turning Point Test, the Box-Pierce Test and the Bartels-Rank Test. The results show that it is possible to predict faults for both known faults and unknown faults. The challenge is to find the optimal algorithm to determine the best decision rules. In the outlook of this study, further methods are presented that aim to solve this challenge.
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Cojbasic, Zarko, Milan Ristanovic, Nemanja Markovic, and Stefan Tesanovic. "Temperature controller optimization by computational intelligence." Thermal Science 20, suppl. 5 (2016): 1541–52. http://dx.doi.org/10.2298/tsci16s5541c.
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In this paper a temperature control system for an automated educational classroom is optimized with several advanced computationally intelligent methods. Controller development and optimization has been based on developed and extensively tested mathematical and simulation model of the observed object. For the observed object cascade P-PI temperature controller has been designed and conventionally tuned. To improve performance and energy efficiency of the system, several metaheuristic optimizations of the controller have been attempted, namely genetic algorithm optimization, simulated annealing optimization, particle swarm optimization and ant colony optimization. Efficiency of the best results obtained with proposed computationally intelligent optimization methods has been compared with conventional controller tuning. Results presented in this paper demonstrate that heuristic optimization of advanced temperature controller can provide improved energy efficiency along with other performance improvements and improvements regarding equipment wear. Not only that presented methodology provides for determination and tuning of the core controller, but it also allows that advanced control concepts such as anti-windup controller gain are optimized simultaneously, which is of significant importance since interrelation of all control system parameters has important influence on the stability and performance of the system as a whole. Based on the results obtained, general conclusions are presented indicating that meta-heuristic computationally intelligent optimization of heating, ventilation, and air conditioning control systems is a feasible concept with strong potential in providing improved performance, comfort and energy efficiency.
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Alajmi, Turki, and Patrick Phelan. "Modeling and Forecasting End-Use Energy Consumption for Residential Buildings in Kuwait Using a Bottom-Up Approach." Energies 13, no. 8 (April 17, 2020): 1981. http://dx.doi.org/10.3390/en13081981.
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To meet the rapid-growing demand for electricity in Kuwait, utility planners need to be informed on the energy consumption to implement energy efficiency measures to manage sustainable load growth and avoid the high costs of increasing generation capacities. The first step of forecasting the future energy profile is to establish a baseline for Kuwait (i.e., a business-as-usual reference scenario where no energy efficiency incentives were given and the adoption of energy efficient equipment is purely market-driven). This paper presents an investigation of creating a baseline end-use energy profile until 2040 for the residential sector in Kuwait by using a bottom-up approach. The forecast consists of mainly two steps: (1) Forecasting the quantity of the residential energy-consuming equipment in the entire sector until 2040 where this paper used a stock-and-flow model that accounted for the income level, electrification, and urbanization rate to predict the quantify of the equipment over the years until 2040, and (2) calculate the unit energy consumption (UEC) for all equipment types using a variety of methods including EnergyPlus simulation models for cooling equipment. By combining the unit energy consumption and quantity of the equipment over the years, this paper established a baseline energy use profile for different end-use equipment for Kuwait until 2040. The results showed that the air conditioning loads accounted for 67% of residential electrical consumption and 72% of residential peak demand in Kuwait. The highest energy consuming appliances were refrigerators and freezers. Additionally, the air conditioning loads are expected to rise in the future, with an average annual growth rate of 2.9%, whereas the lighting and water heating loads are expected to rise at a much lower rate.
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Becchio, Cristina, Marta Carla Bottero, Stefano Paolo Corgnati, Federico Dell’Anna, Valentina Fabi, Carola Lingua, Leonardo Prendin, and Micaela Ranieri. "The effects of indoor and outdoor air pollutants on workers’ productivity in office building." E3S Web of Conferences 111 (2019): 02057. http://dx.doi.org/10.1051/e3sconf/201911102057.
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In the present-day society, people spend about 80% of their time inside buildings, and specifically 30-40% in workplaces. From this evidence, the indoor environmental quality needs to be investigated, and in particular, the possible sources of indoor-outdoor pollutants and their impact on the human health, comfort and productivity. First, through an examination of the indoor sources of pollution, the research analysed the main substances that affect indoor air quality in an office. Second, the pollution of external origin and its effects on the performance of employees were taken into consideration. Two scenarios were designed for a Heating Ventilation Air Conditioning (HVAC) system in an office building; one by the installation of a biocidal filter and the other by a traditional one. Two methods were applied to evaluate and compare those scenarios; the Cost Benefit Analysis and the Monte Carlo Simulation. From a financial point of view, the investment and management costs of the filters were considered. Instead, the annual benefits included increasing productivity and reducing days of absence from work due to illness. The results confirmed the energy and socio-economic efficiency of the antibacterial filter; it can be considered a solution to achieve the best income.
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Fořt, Jan, Jiří Šál, Jan Kočí, and Robert Černý. "Energy Efficiency of Novel Interior Surface Layer with Improved Thermal Characteristics and Its Effect on Hygrothermal Performance of Contemporary Building Envelopes." Energies 13, no. 8 (April 17, 2020): 2012. http://dx.doi.org/10.3390/en13082012.
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Facing the consequences of climate change and fuel price rises, the achievement of the requirements for low-energy consumption of buildings has become a challenging issue. On top of that, increased demands on indoor hygrothermal conditions usually require the utilization of additional heating, ventilation, and air-conditioning (HVAC) systems to maintain a comfortable environment. On this account, several advanced and modern materials are widely investigated as a promising way for reduction of the buildings’ energy consumption including utilization of passive heating/cooling energy. However, the efficiency and suitability of passive strategies depending on several aspects including the influence of location, exterior climatic conditions, load-bearing materials used, and insulation materials applied. The main objective of this study consists of the investigation of the energy performance benefits gained by the utilization of advanced materials in plasters by computational modeling. Results obtained from a computational simulation reveal the capability of the studied passive cooling/heating methods on the moderation of indoor air quality together with the reduction of the diurnal temperature fluctuation. Achieved results disclose differences in terms of energy savings for even small variation in outdoor climate conditions. Additionally, the effectivity of passive cooling/heating alters considerably during the summer and winter periods. Based on the analysis of simulated heat fluxes, the potential energy savings related to improved thermal properties of the applied plaster layer reached up to 12.08% and thus represent an interesting passive solution towards energy sustainability to meet the criteria on modern buildings.
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Yang, Ye, and Zhenyu Li. "Integrated Design and Assessment for Indoor Heating, Ventilation and Air-Conditioning in Hot Summer and Cold Winter Area: A Case Study in China." Buildings 12, no. 11 (November 1, 2022): 1844. http://dx.doi.org/10.3390/buildings12111844.
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Integrated design of the heating, ventilation and air-conditioning (HVAC) is indispensable to green design because the increasing demand for HVAC systems has led to the diversification of indoor terminals for residential buildings, either focusing on energy efficiency or specializing in creating comfortable indoor environments, and they have different impacts on architectural and engineering design. The paper discussed the assessment-based integration design of the HVAC system, and by introducing case experiences, the whole process of the collaboration between architects and engineers was explored. Various methods were used in the research. The analytic hierarchy process (AHP) was employed to develop the assessment structure and calculate weightings; employing fuzzy comprehensive evaluation (FCE), the social performances of HVAC systems were subjectively evaluated; simulation technology was used to calculate the energy performances; the final results were ranked by the order of preference by similarity to ideal solution (TOPSIS). The research perspective of the collaboration between architects and engineers contributed to the existing literature. Besides, different indoor terminals were analyzed from the two disciplines; an assessment tool (ATI) was conducted and could be referred to; the current green building rating tools were analyzed, and suggestions were proposed to promote the integrated design.
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Mui, Kwok Wai, Ling Tim Wong, Manoj Kumar Satheesan, and Anjana Balachandran. "A Hybrid Simulation Model to Predict the Cooling Energy Consumption for Residential Housing in Hong Kong." Energies 14, no. 16 (August 9, 2021): 4850. http://dx.doi.org/10.3390/en14164850.
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In Hong Kong, buildings consume 90% of the electricity generated and over 60% of the city’s carbon emissions are attributable to generating power for buildings. In 2018, Hong Kong residential sector consumed 41,965 TJ (26%) of total electricity generated, with private housing accounting for 52% and public housing taking in 26%, making them the two major contributors of greenhouse gas emissions. Furthermore, air conditioning was the major source consuming 38% of the electricity generated for the residential building segment. Strategizing building energy efficiency measures to reduce the cooling energy consumption of the residential building sector can thus have far-reaching benefits. This study proposes a hybrid simulation strategy that integrates artificial intelligence techniques with a building energy simulation tool (EnergyPlus™) to predict the annual cooling energy consumption of residential buildings in Hong Kong. The proposed method predicts long-term thermal energy demand (annual cooling energy consumption) based on short-term (hourly) simulated data. The hybrid simulation model can analyze the impacts of building materials, construction solutions, and indoor–outdoor temperature variations on the cooling energy consumed in apartments. The results indicate that using low thermal conductivity building materials for windows and external walls can reduce the annual cooling energy consumption by 8.19%, and decreasing the window-to-wall ratio from 80% to 40% can give annual cooling energy savings of up to 18%. Moreover, significant net annual cooling energy savings of 13.65% can be achieved by changing the indoor set-point temperature from 24 °C to 26 °C. The proposed model will serve as a reference for building energy efficiency practitioners to identify key relationships between building physical characteristics and operational strategies to minimize cooling energy demand at a minimal time in comparison to traditional energy estimation methods.
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Hegazi, Yasmine Sabry, Heidi Ahmed Shalaby, and Mady A. A. Mohamed. "Adaptive Reuse Decisions for Historic Buildings in Relation to Energy Efficiency and Thermal Comfort—Cairo Citadel, a Case Study from Egypt." Sustainability 13, no. 19 (September 23, 2021): 10531. http://dx.doi.org/10.3390/su131910531.
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Historic buildings still perform their role today by being utilized either for their original purpose or a new purpose for which they are adapted. These buildings have specific requirements that inhabitants must follow. These requirements and relating uses and maintenance procedures result from adaptive reuse decisions, which may not be the most optimal scenario. The imperative is that historic buildings are used in a manner that, on the one hand, does not endanger their value related to heritage and tradition, and on the other hand, guarantees a degree of utility for their inhabitants, such as acceptable performance with regards to either air cooling or heating. The challenge is how to optimize the use of energy for either air cooling or heating, provided that adaptive reuse decisions are grounded in certain very specific and very rigid principles. The latter render is extremely difficult to meet the twin challenges of ensuring energy efficiency and thermal comfort for inhabitants while at the same time complying with the adaptive reuse principles. To address this challenge and gain an insight into ways of navigating it, a Post Occupancy Evaluation (POE) is conducted in Former Soldier’s Residence in the Cairo Citadel, Cairo, Egypt, which is now used as the National Organization for Urban Harmony’s (NOUH) administrative head office, this research can be considered as a single domain from which many other possible multi-domains can be investigated while studying the case of adaptive reuse. Other aspects such as indoor environmental quality, air quality, acoustics and lighting might act as multiple approaches appear to be widely used according to this review study, and in the future, the authors intend to test this research with the current single approach used in this research, which is the thermal comfort. POE includes both objective and subjective assessment, the POE limitation at this research to those assessment while a multi-perceptional and behavioral factors might be used as physical, contextual, personal, and others. The simulation and the survey methods were employed consecutively to assess the case study. By considering the research results, it was determined that the building consumes unnecessary energy by its current use of air conditioning system.
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Poulsen, Søren Erbs, Maria Alberdi-Pagola, Davide Cerra, and Anna Magrini. "An Experimental and Numerical Case Study of Passive Building Cooling with Foundation Pile Heat Exchangers in Denmark." Energies 12, no. 14 (July 15, 2019): 2697. http://dx.doi.org/10.3390/en12142697.
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Technologies for energy-efficient cooling of buildings are in high demand due to the heavy CO2 footprint of traditional air conditioning methods. The ground source heat pump system (GSHP) installed at the Rosborg Gymnasium in Vejle (Denmark) uses foundation pile heat exchangers (energy piles). Although designed for passive cooling, the GSHP is used exclusively for heating. In a five-week test during the summer of 2018, excess building heat was rejected passively to the energy piles and the ground. Measured energy efficiency ratios are 24–36 and the thermal comfort in conditioned rooms is improved significantly relative to unconditioned reference rooms. A simple model relating the available cooling power to conditioned room and ground temperatures is developed and calibrated to measured test data. Building energy simulation based estimates of the total cooling demand of the building are then compared to corresponding model calculations of the available cooling capacity. The comparison shows that passive cooling is able to meet the cooling demand of Rosborg Gymnasium except for 7–17 h per year, given that room temperatures are constrained to < 26 °C. The case study clearly demonstrates the potential for increasing thermal comfort during summer with highly efficient passive cooling by rejecting excess building heat to the ground.
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Shchetinin, E. Yu. "ENERGY SAVING TECHNOLOGIES IN POWER SUPPLY OF SMART BUILDINGS USING ARTIFICIAL INTELLIGENCE." Vestnik komp'iuternykh i informatsionnykh tekhnologii, no. 194 (August 2020): 29–37. http://dx.doi.org/10.14489/vkit.2020.08.pp.029-037.
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Intelligent energy saving and energy efficiency technologies are the modern large-scale global trend in the energy systems development. The demand for smart buildings is growing not only in the world, but also in Russia, especially in the market of construction and operation of large business centers, shopping centers and other business projects. Accurate cost estimates are important for promoting energy efficiency construction projects and demonstrating their economic attractiveness. The growing number of digital measurement infrastructure, used in commercial buildings, led to increase access to high-frequency data that can be used for anomaly detection and diagnostics of equipment, heating, ventilation, and optimization of air conditioning. This led to the use of modern and efficient machine learning methods that provide promising opportunities to obtain more accurate forecasts of energy consumption of the buildings, and thus increase energy efficiency. In this paper, based on the gradient boosting model, a method of modeling and forecasting the energy consumption of buildings is proposed and computer algorithms are developed to implement it. Energy consumption dataset of 300 commercial buildings was used to assess the effectiveness of the proposed algorithms. Computer simulations showed that the use of these algorithms has increased the accuracy of the prediction of energy consumptionin more than 80 percent of cases compared to other machine learning algorithms.
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Shchetinin, E. Yu. "ENERGY SAVING TECHNOLOGIES IN POWER SUPPLY OF SMART BUILDINGS USING ARTIFICIAL INTELLIGENCE." Vestnik komp'iuternykh i informatsionnykh tekhnologii, no. 194 (August 2020): 29–37. http://dx.doi.org/10.14489/vkit.2020.08.pp.029-037.
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Intelligent energy saving and energy efficiency technologies are the modern large-scale global trend in the energy systems development. The demand for smart buildings is growing not only in the world, but also in Russia, especially in the market of construction and operation of large business centers, shopping centers and other business projects. Accurate cost estimates are important for promoting energy efficiency construction projects and demonstrating their economic attractiveness. The growing number of digital measurement infrastructure, used in commercial buildings, led to increase access to high-frequency data that can be used for anomaly detection and diagnostics of equipment, heating, ventilation, and optimization of air conditioning. This led to the use of modern and efficient machine learning methods that provide promising opportunities to obtain more accurate forecasts of energy consumption of the buildings, and thus increase energy efficiency. In this paper, based on the gradient boosting model, a method of modeling and forecasting the energy consumption of buildings is proposed and computer algorithms are developed to implement it. Energy consumption dataset of 300 commercial buildings was used to assess the effectiveness of the proposed algorithms. Computer simulations showed that the use of these algorithms has increased the accuracy of the prediction of energy consumptionin more than 80 percent of cases compared to other machine learning algorithms.
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Oh, Jewon, Daisuke Sumiyoshi, Masatoshi Nishioka, and Hyunbae Kim. "Examination of Efficient Operation Method of ATES System by Comparison Operation with WTES System of Existent Heat Storage System." Applied Sciences 11, no. 21 (November 3, 2021): 10321. http://dx.doi.org/10.3390/app112110321.
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Aquifer thermal energy storage (ATES) system is widely used mainly in Europe and USA. In this paper, we examined the efficient operation method of ATES by comparing it with the water thermal energy storage (WTES) system of an existent thermal energy storage (TES) system using simulation. This study uses three aquifers: pumping wells, thermal storage wells, and reducing wells. The initial temperature is 19.1 °C groundwater from the surrounding area. ATES systems use the same operating methods as WTES systems to reduce heat storage efficiency and increase energy consumption. The operation that combines the ATES system with the pre-cooling/pre-heating coil can be used for air conditioning operation even if the heat storage diffuses or the pumping temperature changes. The aquifer heat storage system was used for the pre-cooling/pre-heating coil, and the cooling power consumption was reduced by 20%. The heating operation could not maintain heat for a long time due to the influence of groundwater flowing in from the surroundings. Therefore, it is recommended to use the stored heat as soon as possible. When energy saving is important by introducing a pre-cooling/pre-heating coil, the operation is performed by storing heat at a low temperature close to geothermal heat and also using groundwater heat. In addition, if the reduction of peak power in the daytime is important, it is appropriate to operate so that the heat stored in the pre-cooling/pre-heating coil is used up as much as possible. As a result, it was found that it is effective to operate the ATES system in combination with a pre-cooling/pre-heating coil. In cooling operation, ATES-C1-7 was the lowest at coefficient of performance (COP) 2.4 and ATES-C2-14 was the highest at COP 3.7. In heating operation, ATES-H1-45 was the lowest at COP1.2, and in other cases, it was about the same at COP2.4-2.8. In terms of energy efficiency, the heating operation ATES-H1-45 had a low energy efficiency of 4.1 for energy efficiency ratio (EER) and 3.9 for seasonal energy efficiency ratio (SEER). In other cases, the energy efficiency was 8.2–12.4 for EER and 8.7–15.3 for SEER.
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Smith, I. K., N. Stošič, and C. A. Aldis. "Development of the Trilateral Flash Cycle System: Part 3: The Design of High-Efficiency Two-Phase Screw Expanders." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 210, no. 1 (February 1996): 75–93. http://dx.doi.org/10.1243/pime_proc_1996_210_010_02.
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An extensive research and development programme carried out at City University, London, has led to an improved level of understanding of how Lysholm twin screw machines may be used to recover power from two-phase flash expansion processes. The mode of operation of such machines is described together with the various types of rotor shapes used. Details are given of a computer simulation of the expansion process which was used to analyse 636 test results. These were obtained from earlier investigations as well as those of the authors and include three different working fluids, varying rotor profiles and sizes and power outputs of 5–850 kW. Good agreement was obtained between predicted and measured performance parameters and statistical analyses of the results indicate that this is unlikely to be improved without the development of more refined methods of two-phase flow analysis than are currently in use. Included in the tests are a set of measurements of pressure-volume changes within the expander carried out by the authors which confirmed a hitherto unappreciated feature of the expansion process. This is the relatively large pressure drop associated with the initial filling of the volume trapped between the rotors and the casing. The analytical technique thus developed was used both to explain the poor results of earlier studies with water expanders and to estimate optimum design performance. It is shown that, when expanding wet organic fluids, adiabatic efficiencies of over 70 per cent may be obtained at outputs of only 25 kW while multi-megawatt outputs are possible from machines no bigger than large compressors with efficiencies of more than 80 per cent. Two-phase screw expanders may be used not only for large-scale power generation in trilateral flash cycle (TFC) systems, but also in place of throttle valves in vapour compression systems to drive screw compressors in sealed ‘expressor’ units. The coefficient of performance of large refrigeration, air conditioning and heat pump systems may thereby be raised by up to approximately 8 per cent.
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Chemingui, Yassine, Adel Gastli, and Omar Ellabban. "Reinforcement Learning-Based School Energy Management System." Energies 13, no. 23 (December 1, 2020): 6354. http://dx.doi.org/10.3390/en13236354.
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Energy efficiency is a key to reduced carbon footprint, savings on energy bills, and sustainability for future generations. For instance, in hot climate countries such as Qatar, buildings are high energy consumers due to air conditioning that resulted from high temperatures and humidity. Optimizing the building energy management system will reduce unnecessary energy consumptions, improve indoor environmental conditions, maximize building occupant’s comfort, and limit building greenhouse gas emissions. However, lowering energy consumption cannot be done despite the occupants’ comfort. Solutions must take into account these tradeoffs. Conventional Building Energy Management methods suffer from a high dimensional and complex control environment. In recent years, the Deep Reinforcement Learning algorithm, applying neural networks for function approximation, shows promising results in handling such complex problems. In this work, a Deep Reinforcement Learning agent is proposed for controlling and optimizing a school building’s energy consumption. It is designed to search for optimal policies to minimize energy consumption, maintain thermal comfort, and reduce indoor contaminant levels in a challenging 21-zone environment. First, the agent is trained with the baseline in a supervised learning framework. After cloning the baseline strategy, the agent learns with proximal policy optimization in an actor-critic framework. The performance is evaluated on a school model simulated environment considering thermal comfort, CO2 levels, and energy consumption. The proposed methodology can achieve a 21% reduction in energy consumption, a 44% better thermal comfort, and healthier CO2 concentrations over a one-year simulation, with reduced training time thanks to the integration of the behavior cloning learning technique.
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Kotresha, Banjara, and Nagarajan Gnanasekaran. "Comparison of Fluid Flow and Heat Transfer Through Metal Foams and Wire Mesh by Using CFD." Recent Patents on Mechanical Engineering 12, no. 3 (September 26, 2019): 220–26. http://dx.doi.org/10.2174/2212797612666190717163207.
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Background: The unique structural characteristics of the metal foams, such as low density, large surface area, ability to increase turbulence, and increased heat transfer efficiency, are the advantages associated with thermal applications such as electronics cooling, refrigeration air conditioning, etc. The porous metal foam structures are extensively used to enhance heat transfer. Objective: This paper discusses the numerical simulations of a vertical channel filled with metal foam and wire mesh. The fluid flow and heat transfer phenomena of a wire mesh are compared with two different types of metal foams. Metal foams are made of aluminium and copper while the wire mesh is made of brass. The porosity of the metallic porous structures varies from 0.85 to 0.95. Methods: A Darcy extended Forchheirmer model is considered for solving fluid flow through the porous media while the heat transfer through the porous media is predicted using local thermal non-equilibrium model. Results: Initially, the results obtained using the proposed numerical procedures are compared with experimental results available in the literature. The numerical simulations suggest that the pressure drop increases as the velocity of the fluid increases and decreases as the porosity increases. The heat transfer coefficient and Nusselt number are determined for both the metal foams and the wire mesh. Conclusion: The Nusselt number obtained for wire mesh shows almost 90% of the copper metal foam in the same porosity range. The numerical results suggest that the brass wire mesh porous medium can also be used for enhancement of heat transfer. In this article, patents have been discussed.
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Kozminyih, Nicholas, Oleg Onishchenko, and Dmytro Vasylets. "Analysis methods of air conditioning simulation of ship premises." Bulletin of the National Technical University «KhPI» Series: New solutions in modern technologies, no. 7(1229) (February 2, 2017): 24–29. http://dx.doi.org/10.20998/2413-4295.2017.07.04.
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Zhang, Guang Ming, Xue Shen, and Gui Zhong Tang. "Energy Consumption Simulation of the Air Conditioning System in Large-Scale Buildings." Advanced Materials Research 724-725 (August 2013): 1506–9. http://dx.doi.org/10.4028/www.scientific.net/amr.724-725.1506.
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The working environment of air conditioning system in large-scale building is very complex, and there is no significant linear relationship between factors affecting energy consumption and energy demand of air conditioning system. This study adopts a nonlinear regression model: ANN (artificial neural network) model as energy model of air conditioning system. Take outdoor temperature, categorical day-of-week variable, equipment efficiency and terminal load as input, energy demand as output. Use energy consumption data in 2011 for network training, and energy consumption data in 2012 to verify the reliability of model. Based on energy analysis, the operation condition and the characteristics of energy consumption of air conditioning system for large-scale buildings in Nanjing could be precisely represented.
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Alva, Luis H., and Jorge E. Gonza´lez. "Simulation of an Air-Cooled Solar-Assisted Absorption Air Conditioning System." Journal of Solar Energy Engineering 124, no. 3 (August 1, 2002): 276–82. http://dx.doi.org/10.1115/1.1487885.
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This paper investigates the technical feasibility of using a compact, air-cooled, solar-assisted, absorption air conditioning system in Puerto Rico and similar regions. Computer simulations were conducted to evaluate the system’s performance when subjected to dynamic cooling loads. Within the computer model, heat and mass balances are conducted on each component of the system, including the solar collectors, thermal storage tank, the air-cooled condenser, and the air-cooled absorber. Guidance on component design and insight into the effects of such operating factors as ambient air temperature were gained from exercizing the simulation model. Comparisons are made with an absorption air conditioning system that uses a cooling tower instead of air-cooled components. The particular absorption system of study is one that uses lithium bromide and water as the absorbent and refrigerant, respectively. The heat input to the absorption system generator is provided by an array of flat plate collectors that are coupled to a thermal storage tank. Systems having nominal cooling capacities of 10.5, 14, and 17.5 kW were considered. Useful information about the number of collectors needed, storage tank volume, and efficiency of the overall system is presented.
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Liu, Bao Wei. "Distribution of Indoor Air Quality under Air Conditioning Running." Advanced Materials Research 945-949 (June 2014): 976–79. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.976.
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People are constantly committed to seeking new ways that energy saving ventilation can improve indoor air quality. In this paper, methods of theoretical analysis and numerical simulation combining established indoor ventilation jet crash fluid dynamics model to simulate the indoor air, thermal comfort and indoor air quality issues.
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Fan, Yi Peng, Yu Yun Li, Jun Zhou Yang, and Rui Huang. "The Comparative Analysis of an Official and Experimental Building." Advanced Materials Research 986-987 (July 2014): 2184–88. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.2184.
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The simulation software DeST developed by Air Conditioning Research Group Of Tsinghua University has been used in my thesis. We use this software to simulate an official and experimental building’s energy of air conditioning and heating, then compared to the measured efficiency. We analyzed what has caused the simulated and measured energy consumption data difference, providing a reference for rationality of consumption simulation and optimization of building’s operation management.
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Zhang, Hong, and Jia Ming Zhao. "Improvement Measures and Evaluation of Energy Efficiency of Air Conditioning." Advanced Materials Research 468-471 (February 2012): 1989–92. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.1989.
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Air conditioning and refrigeration equipment are more and more widely applied, It’s energy efficiency proportion of total energy consumption is growing. To evaluate energy efficiency and apply high grade energy efficiency of air conditioning , that can bring considerable economic benefits and improve energy-saving initiative for the enterprises. This has great practical significance to realize Chinese energy-saving task. In this paper the air conditioning energy efficiency ratio(EER), seasonal energy efficiency ratio(SEER) and integrated part load value(IPLV) are proposed and analyzed, Many evalution methods are put forword to provide appropriate evaluation criteria for enterprise, and the energy-saving measures on the different assessment criteria are also put forward, It has some guiding significance to improve the efficiency of air conditioning and refrigeration equipment.
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Li, Yong An, Xue Lai Liu, Jia Jia Yan, and Teng Xing. "Research on Wet Thermal Recovery Plant Used by Air Conditioning." Advanced Materials Research 424-425 (January 2012): 1155–58. http://dx.doi.org/10.4028/www.scientific.net/amr.424-425.1155.
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Based on the simulation Computational Fluid Dynamics method, in view of air conditioning with wet thermal recovery plant for heat and mass transfer characteristic, establishes air channels in three-dimensional laminar flow and heat transfer, mass transfer coupling process of mathematical physics model, discusses the air conditioning with wet thermal recovery plant air channels in temperature, concentration and pressure parameters such as distribution, application enthalpy efficiency analysis method to the heat transfer performance is evaluated. The results indicate that structure parameters of wet thermal recovery plant used by air conditioning play important influence for the heat transfer performance and flow resistance performance. The research conclusion provides guidance for air conditioning with wet thermal recovery plant of optimization.
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葉育君, 葉育君, 許云馨 Yu-Chun Yeh, and 王品心 Shin-Yun Hsu. "複合式木構造住宅之日常能源效益及環境衝擊評估研究." 建築學報 118-1, no. 118-1 (December 2021): 061–73. http://dx.doi.org/10.53106/101632122021120118011.
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<p>近年來許多研究都指出木材有助於降低室內溫度，提升室內環境品質，更有益於居住使用者的身體健康，但目前卻缺乏木構造對於改善熱能的效益多寡的研究，無法驗證木構造所改善之實際效益。此外，目前台灣建造木構造之建築價格比鋼筋混凝土貴了1.5倍左右，這些因素均使木構造建築在台灣建築產業無法像鋼筋混凝土構造相同普及，對於一般民眾、建築產業選擇木構造做為建材使用之誘因不足。台灣近年於政策中開始推廣綠建材，推行多項鼓勵綠建材標章申請的措施與多方進行綠建材觀念之推廣宣導，企圖創造綠色環境。然而，台灣習慣性經常使用高耗能及高傳導係數的材料來建構房屋，接著再陸續研究許多降溫與節能的節能綠建築技術，除了增加營運成本以外，也製造額外的耗能與碳排量，這種現象與全球的發展趨勢背道而馳。因此，改造現有的建築材料，以滿足台灣現在和未來的熱舒適性、生活方式、能源效率等對應氣候減緩的問題，是必須思考的課題。木構造建築具有輕質量、永續性等優點，但同時存在耐震、防火等需持續改善的問題，而鋼筋混凝土構造則具有高強度、剛性、造價成本低、跨度較大等優勢。而台灣地區氣候潮濕、悶熱，若居住於複合式木構造住宅可以隔絕地面的濕氣，也可以減少害蟲入侵住宅等情況，同時對於室內具有調節溫濕度的功能，增加環境與居住者之熱舒適。 故本研究嘗試提出台灣高雄地區發展複合式木構造之可能性，在符合相同空調容積的前提之下，模擬可能的住宅型態樣式進行耗能差異及回收年限，再透過生命週期評估於使用維護階段進行環境衝擊的比較。因此本研究將透過EnergyPlus以及SimaPro軟體來進行模擬，比較高雄平地型地區的鋼筋混凝土與複合式木構造連棟式街屋之建築物使用階段日常使用耗能以及廢氣處理階段環境衝擊，期望作為台灣木構造建築未來發展的新選擇。</p> <p> </p><p>Greenhouse gas emissions increase global temperature and cause abnormal climate changes, which led to global warming. Due to the rise of environmental awareness, many countries have successfully implemented energy conservation and carbon reduction policies to curb the speed of global warming and reduce the carbon footprint. There are around 60% houses constructed by reinforced concrete buildings in Taiwan. It leads almost 70% of the energy use of the buildings from the consumption of air conditioners in residential and commercial buildings, which shows that the impact of the construction industry on the environment is very serious. Also, to reduce the heat transfer conductivity of reinforced concrete buildings, Taiwan has studied many international building materials for building insulation performance in recent years. In response to the problem of the climate change, the development of new regulations and materials, leads the development of construction to hybrid construction methods in Taiwan. The hybrid structure of wood construction combines the advantage of rigidity, sustainability and enhance efficiency. At the same time, the international community is actively discussing the possibility of future development of wood construction cities Therefore, this study attempts to propose the possibility of developing hybrid wood construction in Kaohsiung, Taiwan. The energy consumption of Reinforced Concrete and Hybrid wood construction are simulated under the premise of meeting the same air-conditioning volume. Also, through the life cycle assessment for the daily use and maintenance session, environmental impacts and carbon emission are calculated. EnergyPlus and SimaPro software are used for simulation It is expected that a new choice for the future development of wooden construction would be proposed.</p> <p> </p>
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Li, Kui Ning, and Shuai Chen. "Design of Air Conditioning Unit Performance Test Bench for Rail Vehicles." Applied Mechanics and Materials 701-702 (December 2014): 666–74. http://dx.doi.org/10.4028/www.scientific.net/amm.701-702.666.
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Based on the methods and standards related to both domestic and overseas air conditioning unit performance testing, a new air conditioning unit performance test bench for measuring refrigerating capacity has been developed. The test bench, which includes removable exterior environment simulation room and interior environment simulation room, applies air enthalpy method to measure refrigerating capacity of air conditioning unit. The experiment result shows that exterior environment simulation room can save 50% construction cost by using removable room. Its room temperature has high accuracy and stability by using hot air of air conditioning unit and exterior air, which can save 50%-60% energy consumption. The accuracy of testing Bench is less than 4%, which is better than the national standard GB/T 19842-2005.
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SAITO, KIYOSHI, and JONGSOO JEONG. "LATEST SYSTEM SIMULATION MODELS FOR HEATING, REFRIGERATION, AND AIR-CONDITIONING SYSTEMS, AND THEIR APPLICATIONS." International Journal of Air-Conditioning and Refrigeration 20, no. 01 (March 2012): 1230001. http://dx.doi.org/10.1142/s2010132512300017.
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The energy consumption of the systems used in the heating, refrigerating, and air-conditioning field continues to increase. This necessitates improvements to the efficiency of these systems. However, in Japan, the performance of heating, refrigerating, and air-conditioning systems has already been improved greatly owing to the considerable efforts of manufacturers, the government, and academia. Therefore, it will not be easy to further decrease energy consumption simply by improving the efficiency of each system. In order to adhere to the demands of the worldwide energy saving policy, we need to investigate the best combinations and total energy management schemes for heating, refrigeration, and air-conditioning systems. To this end, simulation holds greater promise than actual field-testing because it is not easy to carry out such experiments on actual large-scale systems. High-precision simulation models are necessary for these investigations. Hence, we are developing simulation models for a heat pump, room air-conditioner, desiccant dehumidifier, indirect evaporative cooler, fuel cell, solar panel, and so on. This paper describes high-accuracy simulation models for a CO2 heat pump, absorption heat pump, and desiccant dehumidification system. We also discuss the simulator that we have developed, based on those models. This simulator is called "Energy Flow + M". It is very easy to use because it has a user-friendly GUI. It has already been made available worldwide through the Internet. It is expected to be used to decrease the energy consumed by heating, refrigeration, and air-conditioning systems.
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Luo, Chao, Yulie Gong, Weibin Ma, and Jun Zhao. "Building energy efficiency in Guangdong province, China." Thermal Science 23, no. 5 Part B (2019): 3251–62. http://dx.doi.org/10.2298/tsci170909105l.
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Because of irreversibility on building construction, building energy efficiency design is more depended on simulation technology. Ministry of Housing and Urban?Rural Development of China also stated that China?s building energy consumption accounted for 27.5% of the total energy consumption in 2012. Energy consumption is simulated based on the heat transfer principle of building wall, windows, roof and ventilation. Improved measurements are proposed for simulation cases. The heating, ventilation, and air conditioning energy consumption of benchmark and energy efficiency building are simulated based on EnergyPlus software. The most effective energy-saving measurements of energy efficiency building are improving air-conditioning system performance and thermal properties of wall and window. The results show that the energy efficiency ratio of refrigeration system should be more than three and energy-saving ratio is about 30%. Heat transfer coefficient of wall and window should be less than 1.0 W/m2k- and 2.0 ,W/m2k- the energy-saving ratio is more than 16% and 10%, respectively. The sum energy-saving ratios of refrigeration system, wall and window are about 56%. The energy efficiency ratios of roof and air exchanges number are not very obvious. Some energy-saving technologies with high cost are put forward based on simulation results which provide effective ways for building energy efficiency in Guangdong province, China.
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Chen, Ruijun, Yu-Tung Liu, and Yaw-Shyan Tsay. "An Air Conditioning Design Strategy of the Stepped Hall Based on Building Performance Simulation." Buildings 12, no. 8 (August 19, 2022): 1269. http://dx.doi.org/10.3390/buildings12081269.
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This study proposed an improved air conditioning design strategy based on building performance simulation for a stepped hall. The air velocity and air change rate of the case were measured on-site, which were compared with the simulation data to verify the reliability of the building simulation model. Then, the fully mixing ventilation scheme and the design schemes proposed in this study were simulated. Finally, the building simulation results were summarized to confirm the applicability of the air conditioning design strategy. The building performance results showed that the air distribution performance index (ADPI) value was 76.95% in the original case. Nevertheless, the effective draft temperature (EDT) in the middle seat area exceeded the standard value, indicating that a local cold shock would occur. Moreover, its scale for ventilation efficiency (SVE6) in the residential area was 2.54. However, the SVE6s in the other schemes were between 0.89 and 0.92. It means that the proposed schemes only needed to take one-third of the time to exhaust air. These three indicators’ visualization results can analyze the advantages and disadvantages of each scheme. Therefore, the improved building performance simulation strategy could inspect the design effect and give suggestions quickly for air conditioning design.
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Osipov, S. N., A. V. Zakharenko, and E. M. Shirokova. "On the Energy Efficiency of Indoor Air Conditioning." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 62, no. 4 (August 2, 2019): 325–40. http://dx.doi.org/10.21122/1029-7448-2019-62-4-325-340.
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The increase of average outdoor temperatures and their fluctuations over the past 20 years (as evidenced by the records of summer temperatures in our country) has significantly increased the need for air conditioning premises where people are present for a long time, especially when they are crowded (shops, entertainment halls, classrooms, etc.). The air conditioning process is quite energy-intensive, but the growth of well-being in many republics of the former USSR, as well as the increasing complexity of the physiological adaptation of the human body to rising outdoor temperatures make it possible (and at the same time necessary) to implement these systems on a large scale. It is important to take into account that electricity prices are currently maintained at a high level for homeowners, and in the coming years the prices will only grow. Therefore, the development of new ways of significant increase of the energy efficiency of the indoor air conditioning process is of a great interest. One of these methods is the use of laminar (or close to them) moving layers of conditioned air in a limited area of work or rest of people. Such a zone, about 1.0‒1.2 m height from a floor in each apartment is, e.g., living rooms (bedroom) in which standard temperature conditions are created by means of simple air supplying and air intake devices. In the case of sedentary work of people, the height of such a zone of conditioned air should be increased to 1.3‒1.5 m. It has already been established that the use of laminar (or close to them) air flows allows to reduce the power consumption by two or more times due to significantly reduced heat exchange with the surrounding heated surfaces. Besides, the simplicity of such systems ought to be noted. In particular, in conditions of modern systems of control and management of air conditioning, the "duties" of consumers include only the installation on the control device of the initial data relating directly to the required parameters of the microclimate. At the same time, it should be noted that there is currently no complete scientific and technical description of aerodynamic and heat exchange processes in the air conditioning zone. Even in modern conditions for countries with a sharply continental climate (Russia, Kazakhstan, etc.), the problem is the choice of the type of air conditioner for its effective use in hot periods of summer. In general, it can be noted that all the problems of energy-efficient use of air conditioners must find a comprehensive solution.
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Zhang, Qianru, Yuhong Liu, Jinchi Zhao, and Xin Wang. "Numerical Simulation of Gas-Liquid Two-Phase Leakage of R-290 Refrigerant in Split Air Conditioner." E3S Web of Conferences 356 (2022): 04023. http://dx.doi.org/10.1051/e3sconf/202235604023.
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R290 as a refrigerant has significant advantages of low cost, high energy efficiency, and more environmental protection, but the leakage will form a hazardous area inside the indoor unit and the room where the concentration exceeds the lower flammable limit of propane. In this paper, we focus on the gas-liquid two-phase leakage of R-290 indoor air conditioner at the evaporator, and use Computational Fluid Dynamics (CFD) method to numerically simulate the refrigerant leakage dispersion at three air conditioning supply volumes of 178.2 m3/h, 342 m3/h and 576 m3/h, and analyze the indoor velocity distribution and concentration distribution. The results show that the trajectory of the refrigerant jet changes under different air supply volumes, and the simulation results show that the spatial extent of the combustion explosion limit is mainly distributed at the air conditioning leak and the air conditioning outlet. Vortices were formed in the local area above the propane leakage port and then spread.
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Jalal M. Jalil, Jalal M. Jalil. "CFD Simulation for a Road Vehicle Cabin." journal of King Abdulaziz University Engineering Sciences 18, no. 2 (January 1, 2007): 129–48. http://dx.doi.org/10.4197/eng.18-2.7.
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A numerical study of a two-dimensional, turbulent, recirculating flow within a passenger car cabin is presented. The study is based on the solution of the elliptic partial differential equations representing conservation of mass, momentum, temperature, turbulence energy and its dissipation rate in finite volume form. Algebraic expressions for the turbulent viscosity and diffusion coefficients are calculated using the two-equation model(k − ε). Different parameters are considered to illustrate their influences on the flow filed and temperature distribution inside car cabin. These parameters include number and location of the air conditioning systems inlets inside car cabin, different air temperatures at the inlets, different air velocities at the inlets, different solar intensity during day-time for a certain day of the year, different diffuse solar radiation (variation in the kind of car glass). Generally, the results indicate some of negative effects such as development of zones of low air circulation. Also it is found that the number of inlets inside car cabin play an important role in determining car air conditioning system efficiency. Moreover, the air temperature and velocity at inlets play an important role in determining cabin climate. The results are used to enhance the understating of the airflow fields within a road vehicle passenger cabin.
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Koçak, Sinan, and László Pokorádi. "Comparison of Defuzzification Methods in The Case of Air Conditioning Systems." Műszaki Tudományos Közlemények 9, no. 1 (October 1, 2018): 115–18. http://dx.doi.org/10.33894/mtk-2018.09.24.
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Abstract This paper provides the design for air conditioning system and two different defuzzification methods. The air conditioner intelligent system is the control of two control parameter: the temperature and the humidity of the area. The inputs received by the temperature and humidity sensors give the closest output values for the air conditioning system. The simulation result shows temperature and humidity of the heat exchange by using defuzzification methods of centroid and middle of maxima (MoM) in the Fuzzy Logic Toolbox of MATLAB package program.
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Ablanque, Nicolás, Santiago Torras, Carles Oliet, Joaquim Rigola, and Carlos-David Pérez-Segarra. "Dynamic simulation of indirect air conditioning systems with optimized computational time." E3S Web of Conferences 111 (2019): 04042. http://dx.doi.org/10.1051/e3sconf/201911104042.
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The simulation of HVAC systems is a powerful tool to improve the energy efficiency in buildings. The modelling of such systems faces several obstacles due to both the physical phenomenology present and the numerical resolution difficulties. The present work is an attempt to develop a robust, fast, and accurate model for HVAC systems that can interact with the other relevant systems involved in buildings thermal management. The whole system model has been developed in the form of libraries under the Modelica language to exploit its advantageous characteristics: object-oriented programming, equationbased modelling, and handling of multi-physics. The global resolution is carried out dynamically so that not only steady-state predictions can be conducted but also control strategies can be studied over meaningful periods of time. This latter aspect is crucial for optimizing energy savings. The libraries include models for all the system individual components such as pumps, compressors or heat exchangers (operating with twophase flows and/or moist air) and also models assemblies to account for vapour compression units and liquid circuits. An illustrative example of an indirect air conditioning system is detailed in the present work in order to highlight the model potential.
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Landage, Ajay. "Modeling and Simulation of Heat Pump Air-Conditioning System using Ecofriendly Refrigerants." International Journal for Research in Applied Science and Engineering Technology 9, no. VI (June 15, 2021): 1166–70. http://dx.doi.org/10.22214/ijraset.2021.35145.
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A simulation approach to heat pump systems is proposed in this paper. The evaluation of working fluids is conducted. Moreover, the selected refrigerants are used in the simulation. Subsequently, the system is analyzed in terms of the coefficient of performance (COP) and energy efficiency. Some alternative refrigerants, instead of R22 used R290 refrigerent. It is described the selection of refrigerants adapted to each utilization, based on the thermodynamic and -physical properties, the technological behaviour, costs and use constraints as principal aspects of the environmental protection. Also, it is performed a comparative analysis in function of the total equivalent warming impact (TEWI) for some possible substitutes of refrigerant R22 used in various refrigeration and heat pump systems.
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He, Jiahao. "Design and Optimization of Automotive Air Conditioning Duct Based on CFD Algorithm." Journal of Physics: Conference Series 2386, no. 1 (December 1, 2022): 012095. http://dx.doi.org/10.1088/1742-6596/2386/1/012095.
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Abstract Nowadays, the air conditioner (AC), as an important guarantee for driving comfort and endurance, has attracted more and more attention. The pipe connecting the air conditioner refrigerator and the air outlet of the cockpit instrument panel is known as the air duct. Its structural characteristics and fluid flow characteristics are related to the refrigeration efficiency of the whole air conditioning system. The air supply performance of the air duct directly affects the uniformity of the temperature field and speed field in the car, thus affecting the comfort performance of the car [2]. Limited by the layout space, the design of air conditioning duct is the most difficult part of the design of automobile air conditioning system [1]. Therefore, how to optimize the air duct of automotive air-conditioning to meet the size design of the car while being more energy-efficient is an important research direction. This paper focuses on the simulation design and further optimization of the model of the air duct of automotive air conditioning through CFD algorithm. The author uses the Soildworks software for preliminary modeling, meshes the established model with Meshing, and applies the Fluent software to simulate the fluid flow characteristics in the pipe. By inputting a given flow to the inlets, the air volume of each outlet can be simulated. Based on the initial air-conditioning duct model of a vehicle model, the pipe turbulence problem and the uneven distribution of air volume at each outlet in the simulation process are improved under the condition of ensuring the existing size, and finally the rationality of the improvement is verified.
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Morsli, Souad, Amina Sabeur, Harry Ramenah, Mohammed El Ganaoui, and Rachid Bennacer. "Thermo-Fluid Simulation for Indoor Air Quality and Buildings Thermal Comfort." MATEC Web of Conferences 307 (2020): 01032. http://dx.doi.org/10.1051/matecconf/202030701032.
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Air conditioning systems are seen as a crucial part of any structure because they are directly related to the comfort of the occupants. Finding a conditioning system that exhibits not only a high level of comfort, but also a decrease in energy consumption and cost of the system is now very much preferable, especially with the ever-increasing cost of energy. Mixed convection for different boundary conditions and different configuration is carried out. In addition, a flow is injected through a window and extracted through an opposite window. In this work we examine the influence of the value of the Rayleigh number on the flow structure. The numerical analysis was carried out using the ‘Fluent’ software. To deal with turbulence the RNG k-ε model was adopted in this study. The study of ventilation efficiency has shown that the intensity of the recirculation flow increases near the adiabatic wall with the increase of Rayleigh number.
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Mothiravally, Sachin Sunil, and Sachidananda Hassan Krishanmurthy. "Design of an adiabatic air conditioning package system." International Journal for Simulation and Multidisciplinary Design Optimization 13 (2022): 8. http://dx.doi.org/10.1051/smdo/2021041.
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Air conditioning plays a significant role to maintain a cool atmosphere in warm conditions, However, the power consumed by the machine is higher. The commercial prevailing cooling systems are required to operate ventilation and cooling systems in buildings and in turn consumes more power. These systems apart from consuming electricity it also adds to the CO2 emissions to our environment. These energy consumption and CO2 emissions can be decreased by the assistance of energy effective frameworks to the prevailing air conditioning system. The study was conducted on a package unit of 414.2 kW by measuring the relative humidity, dry bulb, and wet bulb temperature to investigate the effect of indirect evaporative cooling on the systems COP. Also, the modelling of the package unit was done using Creo software and the analysis was carried out using ANSYS considering the flow and thermal analysis for different components of the package units. From this analysis it can be observed that by implementing the adiabatic cooling in package unit it is possible to save energy consumption. From the results it can be concluded that energy efficiency was more and the return on investment is high. Also, coefficient of performance of this machine is high and consumes less electricity and the expected energy savings is 20%.
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Трушляков, Євген Іванович, Андрій Миколайович Радченко, Сергій Анатолійович Кантор, Веніамін Сергійович Ткаченко, Сергій Георгійович Фордуй, and Ян Зонмін. "ВИЗНАЧЕННЯ ПРОЕКТНОЇ ХОЛОДОПРОДУКТИВНОСТІ СИСТЕМИ КОНДИЦІЮВАННЯ ПОВІТРЯ В КОНКРЕТНИХ КЛІМАТИЧНИХ УМОВАХ І РІЗНИМИ МЕТОДАМИ." Aerospace technic and technology, no. 6 (December 24, 2019): 15–19. http://dx.doi.org/10.32620/aktt.2019.6.03.
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The cold output for the heat-moisture treatment of ambient air in air conditioning systems depends on its parameters (temperature and relative humidity), which vary significantly during operation. To determine the installed (design) cooling capacity of air conditioning system chillers, it is proposed to use a reduction in fuel consumption of a power plant or cooling capacity generation following its current conditioning spending over a certain period, since both of these indicators characterize the efficiency of using the installed cooling capacities of the air conditioning system. To extend the results of the investigation to a wide range of air conditioning units, two methods were used to determine the design cooling capacity (refrigerating capacity): by the maximum annual value and by the maximum growth rate of the efficiency indicator. The first method allows choosing the design cooling capacity, which provides a maximum annual reduction in the specific fuel consumption due to air cooling or maximum cooling capacity generation, which is necessary for air cooling following current climatic conditions. The second method allows determining the minimum design (installed) cooling capacity of chillers, which provides the maximum rate of reduction in fuel consumption by the power plant and the increment in the annual cooling capacity generation following the installed cooling capacity of chillers. The efficiency of air conditioning systems was analyzed for different climatic conditions: a temperate climate using the example of Voznesensk city (Ukraine) and the subtropical climate of Nanjing city (China). It is shown that the design cooling capacity values calculated by both indicators of its use efficiency are the same for the same climatic conditions. Wherein, if to determine the design cooling capacity by both methods - by the maximum annual value and the maximum rate of growth of the indicator, its values turned out to be quite close for tropical climatic conditions and somewhat different for a temperate climate.
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Li, Jun, Bo Geng, Zhixian Lin, Min Chen, Liangyou Shao, Yanmin Zhou, and Yuqing Bao. "Multiagent Consensus Control Strategy considering Whole-Process Thermodynamic Characteristics of Air Conditioning Process." Journal of Electrical and Computer Engineering 2021 (July 28, 2021): 1–10. http://dx.doi.org/10.1155/2021/5543298.
Full textAbstract:
Due to the distributed and decentralized characteristics of air conditioning load, the distributed control strategy has advantages for the air conditioning load to participate in the demand response. However, existing approaches focus on the dynamic control performance with very few considerations on the cost. To fill this gap, this paper proposes a multiagent consensus control method considering the whole-process response cost of air conditioning. Based on the thermodynamic characteristics of air conditioning load in the load reduction process and recovery process, the cost function curve of air conditioning load is established. Then, the multiagent consensus control strategy is adopted to send the power adjustment information to each air conditioner to realize the optimal control of the air conditioning load. The simulation results verify that the proposed method can take into account the whole-process response cost of air conditioning loads and result in smaller control cost than existing methods.
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Zhang, Wenhao, and Zhiang Zhang. "Energy Efficient Operation Optimization of Building Air-conditioners via Simulator-assisted Asynchronous Reinforcement Learning." IOP Conference Series: Earth and Environmental Science 1048, no. 1 (July 1, 2022): 012006. http://dx.doi.org/10.1088/1755-1315/1048/1/012006.
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Abstract At present, buildings are the major energy consumers in most developed and developing countries. Energy efficiency is one of the primary objectives of today’s building projects, especially in the context of carbon-peak and carbon-neutral. In buildings, air-conditioning systems account for nearly half of total building energy consumption. Optimal control and operation can significantly improve air-conditioning’s energy efficiency but the key challenge is the complex dynamics of air-conditioning systems. This study focuses the energy efficient operation of air-conditioners in office buildings, and proposes a simulation-assisted reinforcement learning (RL) method to develop energy efficient operation strategies. This study uses a whole building energy simulation model to build the environmental simulator for the air-conditioning system, and uses asynchronous RL algorithm to learn energy efficient operation strategies. Energy saving and Setpoint Not Met is used as the optimization objective as well as the criteria for evaluating the performance of the RL operation strategies. A validation simulator with varied weather conditions is also built to validate the robustness of reinforcement learning. The results show that, compared to common rule-based control strategy, 16.1% energy saving with better thermal comfort can be achieved by the RL operation strategy. In addition, the results also show the RL operation strategy has a certain level of robustness.
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Shi, Wen Ku, Jian Peng Yao, Suo Jun Hou, Fu Xiang Guo, and De Guang Fang. "A Simulation on Aerodynamic Noise of an Air-Conditioning Duck." Advanced Materials Research 466-467 (February 2012): 778–83. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.778.
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The transient flow field is needed in order to predict the aerodynamic noise of an automotive HVAC duck by conventional methods. However, it is time-consuming when are several improved schemes .To solve the problem, schemes with large sound power can be discarded using Broadband Noise Source (BNS) model at first. Then, the best scheme can be found after the transient flow simulation .In this paper, an automotive HVAC duck is used as an example. Firstly BNS is used to predict which scheme is noisier, secondly the aerodynamic noise is computed using Fluent coupled with Sysnoise. At last they come to the same conclusion. The simulation results indicate BNS model can be used to find which scheme is the best without computing the transient flow field. So it can shorten the cycle of developing new products.
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Chen, Yong-Liang, Zi-Qiang Qin, Yao Li, Hai-Bo Wang, Sheryar Muhammad, and Hai-Qing Si. "Optimization of modular data center air conditioning system." International Journal of Modern Physics B 34, no. 14n16 (June 3, 2020): 2040123. http://dx.doi.org/10.1142/s0217979220401232.
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In high-density data center, energy consumption is increasing dramatically. For reducing the energy consumption, CFD software, Fluent 15.0, is used to simulate the flow and temperature field distribution with [Formula: see text] turbulence model and fluid–solid coupling method. Fans on the back of racks are simplified as walls with a certain pressure jump. Severs are treated as solid heat sources and porous media. Simulation results reveal that the temperature distribution on the back of racks is not uniform when air conditioners are arranged face-to-face, and local high temperature points emerge near the side wall of air conditioners. Factors affecting cooling efficiency, such as location of air conditioners, speed of inlets, distance of racks, etc., need to be improved. Geometric model is optimized by using a diagonal rack arrangement and drilling holes on the side wall. Based on this, four different cases with various hot aisle distance are proposed. Single and double modular data center are both simulated. Results of new model are better than those of baseline model.