scholarly journals Development of Energy-Efficient Modes of Installations for Heat Treatment of Concrete Products Using Numerical Calculation Methods

2021 ◽  
Vol 20 (3) ◽  
pp. 195-206
Author(s):  
V. N. Romaniuk ◽  
A. M. Niyakovskii ◽  
A. N. Chichko ◽  
Yu. V. Yatskevich

Production of concrete and reinforced concrete products in the conditions of the Republic of Belarus and in the countries with similar climatic conditions requires heat treatment in heat-technological installations in order to achieve the desired strength of the products at the appointed time, which consumes a great amount of thermal energy.  In this case, the purpose of equipment operating  modes is associated with a number of difficulties when it comes to new products of complex spatial configuration and structure. The optimality criteria of such modes are, as a rule, the duration and temperature limits of processing, providing the required strength with minimal energy consumption. In the conditions of serial production in the case of structurally simple objects, the assignment of heat treatment modes is carried out empirically. As the analysis shows, the modes obtained in this way do not meet the above criteria, especially from the standpoint of energy saving. The paper, using a mathematical model previously developed by the authors, proposes dependencies for calculating the optimal modes of heat treatment of concrete products that are distinguished by a complex spatial shape and multi-component structure. The method is based on three-dimensional transfer equations, taking into account internal sources of heat release due to the ongoing hydration reaction of the active components of the cement clinker, and the boundary conditions corresponding to the structure of the processed product, as well as the type of heat technology device for accelerated hydration. Equations are proposed for calculating the amount of heat energy supplied to the processed product providing a given strength at a specified time. On the example of a manufactured industrial concrete product and for the conditions of an actually used device for accelerated hydration, a comparison has been made between two limiting modes of heat treatment: with isothermal exposure and in its absence. As a result of the performed calculations, the dependences of energy consumption, temperature fields and the degree of hydration in the product for both modes have been obtained and an energy-saving mode of heat treatment corresponding to the case under consideration has been developed. It is shown that the used numerical method allows to solve problems of this type and to achieve thermal energy savings.

2021 ◽  
Vol 8 ◽  
Author(s):  
Catherine Baxevanou ◽  
Dimitrios Fidaros ◽  
Ilias Giannenas ◽  
Eleftherios Bonos ◽  
Ioannis Skoufos

Broiler facilities consume a lot of energy resulting in natural source depletion and greater greenhouse gas emissions. A way to assess the energy performance of a broiler facility is through an energy audit. In the present paper, an energy protocol for an energy audit is presented covering both phases of data collection and data elaboration. The operational rating phase is analytically and extendedly described while a complete mathematical model is proposed for the asset rating phase. The developed energy audit procedure was applied to poultry chambers located in lowland and mountainous areas of Epirus Greece for chambers of various sizes and technology levels. The energy intensity indices varied from 46 to 89 kWh/m2 of chamber area 0.25–0.48 kWh/kg of produced meat or 0.36–1.3 kWh/bird depending on the chamber technology level (insulation, automation, etc.) and the location where the unit was installed. The biggest energy consumer was heating followed by energy consumption for ventilation and cooling. An advanced technology level can improve energy performance by ~ 27%−31%. Proper insulation (4–7 cm) can offer a reduction of thermal energy consumption between 10 and 35%. In adequately insulated chambers, the basic heat losses are due to ventilation. Further energy savings can be achieved with more precise ventilation control. Automation can offer additional electrical energy saving for cooling and ventilation (15–20%). Energy-efficient lights can offer energy saving up to 5%. The use of photovoltaic (PV) technology is suggested mainly in areas where net-metering holds. The use of wind turbines is feasible only when adequate wind potential is available. Solar thermal energy is recommended in combination with a heat pump if the unit's heating and cooling systems use hot/cold water or air. Finally, the local production of biogas with anaerobic fermentation for producing thermal or electrical energy, or cogenerating both, is a choice that should be studied individually for each farm.


Author(s):  
Ivan M. Gryshchenko ◽  
Svitlana V. Bebko

The article reveals the essence of the key motivation drivers to save energy and increase the energy efficiency in higher education institutions. In particular, a low level of interest of higher education institutions in the implementation of strategies to reduce energy consumption has been observed. The findings suggest that the lack of interest in energy saving is primarily affected by budget legislation since the energy cost calculation was based on the consumption norms for a particular budgetary institution and the current (planned) electricity and heat tariffs. Recently, it has been decided that from now on universities will not obtain budget funding to cover utility costs; the amount of subsidies from the Ministry of Education and Science of Ukraine for the implementation of the government objectives will comprise regulatory costs for public service provision according to the student contingent. Standard property maintenance costs will not be covered by the Ministry anymore which will impose the burden of paying the utility bills upon the University’s gross income. Hence, there is a need to take efforts to enhance energy efficiency and energy saving in higher education institutions which was implemented using a foresight methodology. Within the scope of this study, the foresight project to improve the energy efficiency of buildings in the frameworks of the University energy hub is based on the following calculations: thermal energy consumption for heating public buildings, estimated hourly heating load to ensure heating in the building, verifying the feasibility of heating standby regulation, measuring energy savings through the creation of an automated heat supply station, as well as annual savings in monetary terms. In order to save resources and boost energy efficiency based on the University energy hub using an automated heat supply station, the study offers a mathematical toolkit to justify the choice of minimum and maximum values of optimal microclimate parameters; reduce infiltration, increase the efficiency of indoor air distribution; optimal modes of local air conditioning, preheating and cooling; utilizing of "waste" and natural heat and cold; "combining" microclimate systems with other systems; improving automation devices in technical systems. It is argued that increasing the energy efficiency of heating systems in University buildings on the basis of its own energy hub will contribute to gaining significant savings in thermal energy for heating and significantly reduce carbon dioxide emissions into the environment. In addition, the study reveals that the cost of thermal energy for heating depends upon a building design, modernization quality, reconstruction and insulation, applied building materials, spatial planning solutions, the presence or absence of control and automated systems, maintenance systems and attitude of owner’s attitude to innovations. The conclusions summarize that the cost of thermal energy can vary significantly in buildings of the same type.


2015 ◽  
Vol 8 (1) ◽  
pp. 206-210 ◽  
Author(s):  
Yu Junyang ◽  
Hu Zhigang ◽  
Han Yuanyuan

Current consumption of cloud computing has attracted more and more attention of scholars. The research on Hadoop as a cloud platform and its energy consumption has also received considerable attention from scholars. This paper presents a method to measure the energy consumption of jobs that run on Hadoop, and this method is used to measure the effectiveness of the implementation of periodic tasks on the platform of Hadoop. Combining with the current mainstream of energy estimate formula to conduct further analysis, this paper has reached a conclusion as how to reduce energy consumption of Hadoop by adjusting the split size or using appropriate size of workers (servers). Finally, experiments show the effectiveness of these methods as being energy-saving strategies and verify the feasibility of the methods for the measurement of periodic tasks at the same time.


Author(s):  
Hui Yang ◽  
Anand Nayyar

: In the fast development of information, the information data is increasing in geometric multiples, and the speed of information transmission and storage space are required to be higher. In order to reduce the use of storage space and further improve the transmission efficiency of data, data need to be compressed. processing. In the process of data compression, it is very important to ensure the lossless nature of data, and lossless data compression algorithms appear. The gradual optimization design of the algorithm can often achieve the energy-saving optimization of data compression. Similarly, The effect of energy saving can also be obtained by improving the hardware structure of node. In this paper, a new structure is designed for sensor node, which adopts hardware acceleration, and the data compression module is separated from the node microprocessor.On the basis of the ASIC design of the algorithm, by introducing hardware acceleration, the energy consumption of the compressed data was successfully reduced, and the proportion of energy consumption and compression time saved by the general-purpose processor was as high as 98.4 % and 95.8 %, respectively. It greatly reduces the compression time and energy consumption.


Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 81
Author(s):  
Rongjiang Ma ◽  
Shen Yang ◽  
Xianlin Wang ◽  
Xi-Cheng Wang ◽  
Ming Shan ◽  
...  

Air-conditioning systems contribute the most to energy consumption among building equipment. Hence, energy saving for air-conditioning systems would be the essence of reducing building energy consumption. The conventional energy-saving diagnosis method through observation, test, and identification (OTI) has several drawbacks such as time consumption and narrow focus. To overcome these problems, this study proposed a systematic method for energy-saving diagnosis in air-conditioning systems based on data mining. The method mainly includes seven steps: (1) data collection, (2) data preprocessing, (3) recognition of variable-speed equipment, (4) recognition of system operation mode, (5) regression analysis of energy consumption data, (6) constraints analysis of system running, and (7) energy-saving potential analysis. A case study with a complicated air-conditioning system coupled with an ice storage system demonstrated the effectiveness of the proposed method. Compared with the traditional OTI method, the data-mining-based method can provide a more comprehensive analysis of energy-saving potential with less time cost, although it strongly relies on data quality in all steps and lacks flexibility for diagnosing specific equipment for energy-saving potential analysis. The results can deepen the understanding of the operating data characteristics of air-conditioning systems.


Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 344
Author(s):  
Alejandro Humberto García Ruiz ◽  
Salvador Ibarra Martínez ◽  
José Antonio Castán Rocha ◽  
Jesús David Terán Villanueva ◽  
Julio Laria Menchaca ◽  
...  

Electricity is one of the most important resources for the growth and sustainability of the population. This paper assesses the energy consumption and user satisfaction of a simulated air conditioning system controlled with two different optimization algorithms. The algorithms are a genetic algorithm (GA), implemented from the state of the art, and a non-dominated sorting genetic algorithm II (NSGA II) proposed in this paper; these algorithms control an air conditioning system considering user preferences. It is worth noting that we made several modifications to the objective function’s definition to make it more robust. The energy-saving optimization is essential to reduce CO2 emissions and economic costs; on the other hand, it is desirable for the user to feel comfortable, yet it will entail a higher energy consumption. Thus, we integrate user preferences with energy-saving on a single weighted function and a Pareto bi-objective problem to increase user satisfaction and decrease electrical energy consumption. To assess the experimentation, we constructed a simulator by training a backpropagation neural network with real data from a laboratory’s air conditioning system. According to the results, we conclude that NSGA II provides better results than the state of the art (GA) regarding user preferences and energy-saving.


2021 ◽  
Vol 11 (2) ◽  
pp. 542
Author(s):  
Jaqueline Litardo ◽  
Massimo Palme ◽  
Rubén Hidalgo-León ◽  
Fernando Amoroso ◽  
Guillermo Soriano

This paper compares the potential for building energy saving of various passive and active strategies and on-site power generation through a grid-connected solar photovoltaic system (SPVS). The case study is a student welfare unit from a university campus located in the tropical climate (Aw) of Guayaquil, Ecuador. The proposed approach aims to identify the most effective energy saving strategy for building retrofit in this climate. For this purpose, we modeled the base line of the building and proposed energy saving scenarios that were evaluated independently. All building simulations were done in OpenStudio-EnergyPlus, while the on-site power generation was carried out using the Homer PRO software. Results indicated that the incorporation of daylighting controls accounted for the highest energy savings of around 20% and 14% in total building energy consumption, and cooling loads, respectively. Also, this strategy provided a reduction of about 35% and 43% in total building energy consumption, and cooling loads, respectively, when combined with triple low-e coating glazing and active measures. On the other hand, the total annual electric energy delivered by the SPVS (output power converter) was 66,590 kWh, from where 48,497 kWh was supplied to the building while the remaining electricity was injected into the grid.


Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 442
Author(s):  
Xiaoyue Zhu ◽  
Bo Gao ◽  
Xudong Yang ◽  
Zhong Yu ◽  
Ji Ni

In China, a surging urbanization highlights the significance of building energy conservation. However, most building energy-saving schemes are designed solely in compliance with prescriptive codes and lack consideration of the local situations, resulting in an unsatisfactory effect and a waste of funds. Moreover, the actual effect of the design has yet to be thoroughly verified through field tests. In this study, a method of modifying conventional building energy-saving design based on research into the local climate and residents’ living habits was proposed, and residential buildings in Panzhihua, China were selected for trial. Further, the modification scheme was implemented in an actual project with its effect verified by field tests. Research grasps the precise climate features of Panzhihua, which was previously not provided, and concludes that Panzhihua is a hot summer and warm winter zone. Accordingly, the original internal insulation was canceled, and the shading performance of the windows was strengthened instead. Test results suggest that the consequent change of SET* does not exceed 0.5 °C, whereas variations in the energy consumption depend on the room orientation. For rooms receiving less solar radiation, the average energy consumption increased by approximately 20%, whereas for rooms with a severe western exposure, the average energy consumption decreased by approximately 11%. On the other hand, the cost savings of removing the insulation layer are estimated at 177 million RMB (1 USD ≈ 6.5 RMB) per year. In conclusion, the research-based modification method proposed in this study can be an effective tool for improving building energy efficiency adapted to local conditions.


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