METHOD FOR STUDYING THE INFLUENCE OF THERMAL INERTIA ON THE ROOM TEMPERATURE

2021 ◽  
Vol 7 (2) ◽  
pp. 188-205
Author(s):  
Artur R. ROMAZANOV ◽  
Irina G. ZAKHAROVA
Keyword(s):  
Data Analysis ◽  
Thermal Energy ◽  
Thermal Regime ◽  
Thermal Inertia ◽  
Weather Conditions ◽  
Heating System ◽  
Lag Time ◽  
Classification Model ◽  
Time Interval ◽  
Factors Affecting

The efficiency of using thermal energy that is received from the central heating system to supply a building (a complex of interconnected rooms) is determined by the completeness of information available on the factors that affect the thermal regime. This article presents an approach that allows evaluating the significance for thermal management of such complex parameters as thermal inertia of a room and features of its use. The proposed methodology is based on the analysis of the dynamics of temperature changes in rooms, considering the standard characteristics that determine heat exchange, meteorological conditions, and the presence of people. The degree of the thermal inertia influence on a room is determined on the lag time, which is the time interval between a significant change in weather conditions or the supply of thermal energy and a change in the air temperature in the room. The initial data included the values of the temperature of the air and heating elements, that were obtained from the sensors located in a university building. The observation was conducted between 1 March and 19 April 2020 (measurement frequency — 10 minutes). The collected data consist of measurements gathered during room usage in different modes. Additionally, the presence of periods of complete shutdown of the heating system also affected the respective data. The module of the intelligent monitoring system for the thermal regime of the building was developed to perform data analysis. The module was implemented as a pipeline that sequentially performs the following operations: filtering and cleaning data; aggregation for specified periods; determination of the delay time. The results of the data analysis show the possibility of selecting groups of rooms that react to significant changes in external conditions and heating mode with a remarkable lag time. This confirms the importance of considering the thermal inertia for efficient heating control (intermittent operation). The results allow concluding that it is possible to build a classification model based on the thermal inertia parameter. These models will help in determining the most significant factors affecting the thermal regime of the room. In its turn, it allows producing recommendations for making decisions on heat supply management.

scholarly journals A Parametric Study of a Solar-Assisted House Heating System with a Seasonal Underground Thermal Energy Storage Tank

2020 ◽  
Vol 12 (20) ◽  
pp. 8686 ◽  
Author(s):  
Le Minh Nhut ◽  
Waseem Raza ◽  
Youn Cheol Park
Keyword(s):  
Mathematical Model ◽  
Energy Storage ◽  
South Korea ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage Tank ◽  
Fossil Fuels ◽  
Weather Conditions ◽  
Heating System ◽  
Thickness Effect

The requirement for energy is increasing worldwide as populations and economies develop. Reasons for this increase include global warming, climate change, an increase in electricity demand, and paucity of fossil fuels. Therefore, research in renewable energy technology has become a central topic in recent studies. In this study, a solar-assisted house heating system with a seasonal underground thermal energy storage tank is proposed based on the reference system to calculate the insulation thickness effect, the collector area, and an underground storage tank volume on the system performance according to real weather conditions at Jeju Island, South Korea. For this purpose, a mathematical model was established to calculate its operating performance. This mathematical model used the thermal response factor method to calculate the heat load and heat loss of the seasonal underground thermal energy storage tank. The results revealed that on days with different weather conditions, namely, clear weather, intermittent clouds sky, and overcast sky, the obtained solar fraction was 45.8%, 17.26%, and 0%, respectively. Using this method, we can save energy, space, and cost. This can then be applied to the solar-assisted house heating system in South Korea using the seasonal underground thermal energy storage tank.

scholarly journals STRUCTURAL SOLUTIONS IMPACT ON THERMAL ENERGY EFFICIENCY OF HEATING SURFACE AT AN OPEN SPACE

2013 ◽  
Vol 19 (6) ◽  
pp. 883-893 ◽  
Author(s):  
Dobrosława Kaczorek ◽  
Halina Koczyk
Keyword(s):  
Energy Efficiency ◽  
Thermal Energy ◽  
Open Space ◽  
Heating Surface ◽  
Ground Level ◽  
Weather Conditions ◽  
Heating System ◽  
Climatic Conditions ◽  
Simulation Research ◽  
Structural Solutions

This paper presents studies on thermal energy efficiency of heating surface at an open space according to structural solutions and climatic conditions. Numerical simulation research was conducted to assess three different types of heating surfaces at an open space over chosen period of time in real weather conditions. Performance parameters such as surface temperature, supply temperature and efficiency of heating surface relative to constructional designs and model of control strategy used were analysed. The number, thickness and type of material layers beneath ground level were modified. The distance between heating pipes and their diameters were kept constant. The carried out analyses show that the used solutions can lead to significant differences in the performance and consequently in the energy efficiency of the heating system for open spaces.

Joint Calculation of the Non-Stationary Thermal Mode of a Building and its Water Heating System

2018 ◽  
Vol 931 ◽  
pp. 905-909 ◽  
Author(s):  
Elena G. Malyavina
Keyword(s):  
Real Time ◽  
Thermal Energy ◽  
Thermal Regime ◽  
Energy Supply ◽  
Heating System ◽  
Thermal Processes ◽  
Thermal Mode ◽  
Water Heating ◽  
Time Step ◽  
Quantity Of Heat

The solution of the problem of joint cooling of the building and its water heating system, in case of the thermal energy supply termination, is relevant, since only it can determine the real time available to repair crews to restore the operation of the heating system of each object. The article gives a brief description of the algorithms for calculating the non-stationary hydraulic and thermal regime of the heating system and the algorithm for calculating the non-stationary thermal regime of the building. The joint implementation of both algorithms is based on taking into account the influence of the thermal regime of the system and the building on each other at each time step. Linking of thermal processes in a heating system and in a building is carried out taking into account in their thermal balances of the same quantity of heat flowing for a step on time from a heating system element to the room or vice versa. Calculations on the proposed PC program investigated the influence of different factors on the cooling time of the heating system and the whole building.

scholarly journals REQUIRED ADDITIONAL HEATING POWER OF BUILDING DURING INTERMITTED HEATING

2010 ◽  
Vol 16 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Darius Pupeikis ◽  
Arūnas Burlingis ◽  
Vytautas Stankevičius
Keyword(s):  
Energy Consumption ◽  
Thermal Energy ◽  
Energy Savings ◽  
Thermal Inertia ◽  
Heating System ◽  
Heating Power ◽  
Effective Solution ◽  
Intermittent Heating ◽  
One Year ◽  
Reduced Temperature

By introduction of intermittent heating of building we can reduce the thermal energy consumption for heating. But it requires the additional power of heating system. It is determined that the most effective solution for energy savings is to enlarge the heating power approximately by 50% for most of buildings. The simulation has showed that for buildings with a medium thermal inertia (time constant τ = 144 h) the expenses by employing the intermittent heating (reduced temperature period: 12 h on working days and 48 h at weekends), pays back after one year. By designing the heating system we must pay attention to thermal inertia of building. Our research showed that for various thermal inertias of building, the adequate modes of intermittent heating must be chosen. Santrauka Šildant pastata, esant papildomai šiluminei galiai, galima sumažinti sunaudojamos šilumines energijos. Nustatyta, kad papildomos šilumines galios (+50 %) sanaudos, siekiant pagreitinti temperatūros padidinima vidutinio masyvumo (τ = 144 h) pastatu patalpose ir taikant protarpini šildyma (12 h darbo dienomis ir 48 h savaitgaliais), atsiperka po vieneriu metu. Projektuojant reikia atsižvelgti i pastato paskirti, masyvuma ir šildymo sistemos galia, siekiant sutaupyti šilumines energijos bei gauti ekonomine nauda, taikant protarpini šildyma. Tyrimai parode, kad ivairaus masyvumo pastatams turi būti taikomi atitinkami protarpinio šildymo periodai.

scholarly journals Online Implementation of a Soft Actor-Critic Agent to Enhance Indoor Temperature Control and Energy Efficiency in Buildings

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 997
Author(s):  
Davide Coraci ◽  
Silvio Brandi ◽  
Marco Savino Piscitelli ◽  
Alfonso Capozzoli
Keyword(s):  
Energy Consumption ◽  
Temperature Control ◽  
Weather Conditions ◽  
Heating System ◽  
Building Envelope ◽  
Indoor Temperature ◽  
Model Free ◽  
Occupancy Patterns ◽  
Online Implementation ◽  
Indoor Temperature Control

Recently, a growing interest has been observed in HVAC control systems based on Artificial Intelligence, to improve comfort conditions while avoiding unnecessary energy consumption. In this work, a model-free algorithm belonging to the Deep Reinforcement Learning (DRL) class, Soft Actor-Critic, was implemented to control the supply water temperature to radiant terminal units of a heating system serving an office building. The controller was trained online, and a preliminary sensitivity analysis on hyperparameters was performed to assess their influence on the agent performance. The DRL agent with the best performance was compared to a rule-based controller assumed as a baseline during a three-month heating season. The DRL controller outperformed the baseline after two weeks of deployment, with an overall performance improvement related to control of indoor temperature conditions. Moreover, the adaptability of the DRL agent was tested for various control scenarios, simulating changes of external weather conditions, indoor temperature setpoint, building envelope features and occupancy patterns. The agent dynamically deployed, despite a slight increase in energy consumption, led to an improvement of indoor temperature control, reducing the cumulative sum of temperature violations on average for all scenarios by 75% and 48% compared to the baseline and statically deployed agent respectively.

scholarly journals Financing Growth through Remittances and Foreign Direct Investment: Evidences from Balkan Countries

2021 ◽  
Vol 14 (3) ◽  
pp. 117
Author(s):  
Esmeralda Jushi ◽  
Eglantina Hysa ◽  
Arjona Cela ◽  
Mirela Panait ◽  
Marian Catalin Voica
Keyword(s):  
Developing Economies ◽  
Central Banks ◽  
Sustainable Growth ◽  
Time Interval ◽  
Foreign Direct Investments ◽  
Factors Affecting ◽  
Balkan Countries ◽  
To Come ◽  
Sustainable Economic Growth ◽  
The Impact

The ultimate goal of central banks, worldwide, is to promote the foundations for sustainable economic growth. In the case of developing economies, in particular, such objective requires time, huge efforts, attention, and plenty of resources in order to be accomplished to the fullest degree. This paper thoroughly investigates key factors affecting Balkan countries’ economic development (as measured by gross domestic product (GDP) growth), focusing especially on the impact of remittances. The analysis was done over an 18-year time interval (2000–2017) and builds on 144 observations. The data figures were retrieved from the World Bank database while two dummies were created to test the impact of the last financial crisis (2008–2012). Econometric tools were employed to carry out a broad analysis on the interdependencies that exist and, in particular, to determine the role of remittance income on growth. The vector auto regressive model was estimated using EViews software, and was used to come up with relevant insights. Empirical findings suggest the following: population growth, remittances, and labor force participation are insignificant factors for sustainable growth. On the other hand, previous levels of GDP, trade, and foreign direct investments (FDIs) appear to be relevant for the predictor. This research provides up-to-date conclusions, which can be considered during the decision-making process of central banks, as well as by government policymakers.

scholarly journals Computer-Assisted System in Stress Radiography for Anterior Cruciate Ligament Injury with Correspondent Evaluation of Relevant Diagnostic Factors

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 419
Author(s):  
Chien-Kuo Wang ◽  
Liang-Ching Lin ◽  
Yung-Nien Sun ◽  
Cheng-Shih Lai ◽  
Chia-Hui Chen ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Cruciate Ligament ◽  
Anterior Tibial Translation ◽  
Computer Assisted ◽  
Time Interval ◽  
Stress Radiography ◽  
Factors Affecting ◽  
Anterior Tibial ◽  
Anterior Cruciate ◽  
Tibial Translation

We sought to design a computer-assisted system measuring the anterior tibial translation in stress radiography, evaluate its diagnostic performance for an anterior cruciate ligament (ACL) tear, and assess factors affecting the diagnostic accuracy. Retrospective research for patients with both knee stress radiography and magnetic resonance imaging (MRI) at our institution was performed. A complete ACL rupture was confirmed on an MRI. The anterior tibial translations with four different methods were measured in 249 patients by the designed algorithm. The diagnostic accuracy of each method in patients with all successful measurements was evaluated. Univariate logistic regression analysis for factors affecting diagnostic accuracy of method four was performed. In the inclusive 249 patients, 177 patients (129 with completely torn ACLs) were available for analysis. Mean anterior tibial translations were significantly increased in the patients with a completely torn ACL by all four methods, with diagnostic accuracies ranging from 66.7% to 75.1%. The diagnostic accuracy of method four was negatively associated with the time interval between stress radiography and MRI as well as force-joint distance on stress view, and not significantly associated with age, gender, flexion angle, intercondylar distance, and force-joint angle. A computer-assisted system measuring the anterior tibial translation in stress radiography showed acceptable diagnostic performance of complete ACL injury. A shorter time interval between stress radiography and MRI as well as shorter force-joint distance were associated with higher diagnostic accuracy.

Ultrasonic device for real-time sewage velocity and suspended particles concentration measurements

2009 ◽  
Vol 60 (1) ◽  
pp. 117-125 ◽  
Author(s):  
F. Abda ◽  
A. Azbaid ◽  
D. Ensminger ◽  
S. Fischer ◽  
P. François ◽  
...  
Keyword(s):  
Data Analysis ◽  
Suspended Solids ◽  
Weather Conditions ◽  
Suspended Particles ◽  
Inversion Method ◽  
Ultrasonic Device ◽  
Size Classes ◽  
Identification Method ◽  
Spectral Identification ◽  
Water Height

In the frame of a technological research and innovation network in water and environment technologies (RITEAU, Réseau de Recherche et d'Innovation Technologique Eau et Environnement), our research group, in collaboration with industrial partners and other research institutions, has been in charge of the development of a suitable flowmeter: an ultrasonic device measuring simultaneously the water flow and the concentration of size classes of suspended particles. Working on the pulsed ultrasound principle, our multi-frequency device (1 to 14 MHz) allows flow velocity and water height measurement and estimation of suspended solids concentration. Velocity measurements rely on the coherent Doppler principle. A self developed frequency estimator, so called Spectral Identification method, was used and compared to the classical Pulse-Pair method. Several measurements campaigns on one wastewater collector of the French city of Strasbourg gave very satisfactory results and showed smaller standard deviation values for the Doppler frequency extracted by the Spectral Identification method. A specific algorithm was also developed for the water height measurements. It relies on the water surface acoustic impedance rupture and its peak localisation and behaviour in the collected backscattering data. This algorithm was positively tested on long time measurements on the same wastewater collector. A large part of the article is devoted to the measurements of the suspended solids concentrations. Our data analysis consists in the adaptation of the well described acoustic behaviour of sand to the behaviour of wastewater particles. Both acoustic attenuation and acoustic backscattering data over multiple frequencies are analyzed for the extrapolation of size classes and respective concentrations. Under dry weather conditions, the massic backscattering coefficient and the overall size distribution showed similar evolution whatever the measurement site was and were suggesting a global wastewater particles behaviour. By comparison to sampling data, our data analysis lead to the characterization of two particle groups: the ones occurring during rain events and the ones typical of wastewater under dry weather conditions. Even with already encouraging results on the several weeks of data recorded on several wastewater collectors, the validation of our data inversion method is still under progress.

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