scholarly journals Mathematical Analysis of Optimal Operating Conditions in Heating Systems

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Chan Kong ◽  
Yong Sun ◽  
Hongxi Zhang ◽  
Yongjiang Shi
Keyword(s):  
Water Temperature ◽  
Flow Rate ◽  
Heating System ◽  
Optimal Operation ◽  
Operating Conditions ◽  
Experimental Results ◽  
Optimal Operating ◽  
Heating Systems ◽  
Operation Conditions ◽  
Supply Water

With changes in the outdoor air temperature, the heat consumption of buildings also changes. Timely adjustment of the heating systems to ensure optimal operating conditions is extremely significant to save energy. In this study, the operation conditions of a heating system were analyzed numerically, and the existence, uniqueness, and stability of the optimal operation conditions of the heating system were proved. An operation optimization model that could obtain the optimal operation conditions was also established, and the correctness of the model was verified experimentally. Experimental results showed that when the flow rate was 0.606 m3/h, the supply water temperature was 67.13°C, water return temperature was 65.90°C, and the pump consumed the least amount of electricity. The experimental results and model calculation results showed that the operating cost is lower when the system flow rate is low and the supply water temperature is high under the same heat dissipation and indoor temperature.

scholarly journals STUDY AND OPTIMIZATION OF ELECTRIC HEATING FOR OIL AND PETROLEUM PRODUCTS PIPELINE

2017 ◽  
Vol 3 ◽  
pp. 242 ◽  
Author(s):  
Alexander Pavlov ◽  
Igor Plohov ◽  
Sergei Drozdov ◽  
Vadim Smirnov
Keyword(s):  
Electric Heating ◽  
Heating System ◽  
Petroleum Products ◽  
Operating Conditions ◽  
Design Parameters ◽  
Energy Losses ◽  
The Finite Element Method ◽  
Optimal Operating ◽  
Heating Systems ◽  
Products Pipeline

The objectives of the study are to analyze the transients in heated pipelines using the finite element method and the achievement of reduction of energy losses during transportation of liquids in pipelines with electric heating systems by determining the optimal operating conditions and design parameters of the pipeline and electric heating system

scholarly journals Chemical–Electrochemical Process Concept for Lead Recovery from Waste Cathode Ray Tube Glass

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1546
Author(s):  
Árpád Imre-Lucaci ◽  
Melinda Fogarasi ◽  
Florica Imre-Lucaci ◽  
Szabolcs Fogarasi
Keyword(s):  
Flow Rate ◽  
Current Density ◽  
Complete Recovery ◽  
Electrochemical Process ◽  
Operating Conditions ◽  
General Effect ◽  
Optimal Operating ◽  
Recirculation Flow ◽  
Lead Recovery ◽  
Cathode Ray Tube

This paper presents a novel approach for the recovery of lead from waste cathode-ray tube (CRT) glass by applying a combined chemical-electrochemical process which allows the simultaneous recovery of Pb from waste CRT glass and electrochemical regeneration of the leaching agent. The optimal operating conditions were identified based on the influence of leaching agent concentration, recirculation flow rate and current density on the main technical performance indicators. The experimental results demonstrate that the process is the most efficient at 0.6 M acetic acid concentration, flow rate of 45 mL/min and current density of 4 mA/cm2. The mass balance data corresponding to the recycling of 10 kg/h waste CRT glass in the identified optimal operating conditions was used for the environmental assessment of the process. The General Effect Indices (GEIs), obtained through the Biwer Heinzle method for the input and output streams of the process, indicate that the developed recovery process not only achieve a complete recovery of lead but it is eco-friendly as well.

Photo-degradation of butyl parahydroxybenzoate by using TiO2-supported catalyst

2013 ◽  
Vol 67 (10) ◽  
pp. 2141-2147 ◽  
Author(s):  
Patrick Atheba ◽  
Patrick Drogui ◽  
Brahima Seyhi ◽  
Didier Robert
Keyword(s):  
Flow Rate ◽  
Photocatalytic Oxidation ◽  
Supported Catalyst ◽  
Operating Conditions ◽  
Treatment Efficiency ◽  
Optimal Operating ◽  
Photo Degradation ◽  
Photochemical Process ◽  
Recirculation Flow ◽  
High Treatment

The present work evaluates the potential of the photocatalysis (PC) process for the degradation of butylparaben (BPB). Relatively high treatment efficiency was achieved by comparison to photochemical process. Prior to photocatalytic degradation, adsorption (AD) of BPB occurred on the titanium dioxide (TiO2)-supported catalyst. AD was described by Langmuir isotherm (KL = 0.085 L g−1, qm = 4.77 mg g−1). The influence of angle of inclination of the reactor, pH, recirculation flow rate and initial concentration of BPB were investigated. The PC process applied under optimal operating conditions (recirculation flow rate of 0.15 L min−1, angle of inclination of 15°, pH = 7 and 5 mg L−1 of BPB) is able to oxidize 84.9–96.6% of BPB and to ensure around 38.7% of mineralization. The Langmuir–Hinshelwood kinetic model described well the photocatalytic oxidation of BPB (k = 7.02 mg L−1 h−1, K = 0.364 L mg−1).

Application of Additives in 1,8-Cineole Purification

2013 ◽  
Vol 634-638 ◽  
pp. 382-385
Author(s):  
Ke Guo Liu ◽  
Li Li Gu ◽  
Hui Guang Hu ◽  
Rong Yang ◽  
Jun Tao
Keyword(s):  
Experimental Studies ◽  
Optimal Operation ◽  
Experimental Results ◽  
Second Step ◽  
Reflux Ratio ◽  
Batch Distillation ◽  
Operation Temperature ◽  
Operation Conditions ◽  
Vacuum Degree

The experimental studies for purification of 1,8-cineole by vacuum batch distillation as well as the application of additives in 1,8-cineole purification were carried out. There were two steps during the purification. In the first step, experimental results showed that the optimal operation conditions for purification of 1,8-cineole were the temperature of the reboiler at about 320.15 K under a certain vacuum degree. In the second step, the optimal operation temperature of the reboiler was 331.15 K. The optimal reflux ratio was generated finally. Vacuum degree was controlled between 1.1 kPa and 1.3 kPa.

The Influence of Ambient Pressure on the Dynamic Response of RF MEMS Switches

2010 ◽  
Author(s):  
Avihay Ohana ◽  
Oren Aharon ◽  
Ronen Maimon ◽  
Boris Nepomnyashchy ◽  
Lior Kogut
Keyword(s):  
Rf Mems ◽  
Ambient Pressure ◽  
Actuation Voltage ◽  
Operating Conditions ◽  
Experimental Results ◽  
Release Time ◽  
Q Factor ◽  
Optimal Operating ◽  
Mems Switches ◽  
Rf Mems Switches

A study of the dynamic behavior of an RF MEMS switch is presented at different operating conditions. Experimental results for the actuation and release time and Q-factor as a function of the ambient pressure and actuation voltage are compared to theoretical predictions based on existing model. Optimal operating conditions (ambient pressure and actuation voltage) are determined based on two criterions: minimal actuation and release time and minimal oscillations upon switch release. In light of the experimental results optimal operating conditions determined to be 1.4Vpi at a pressure of a few torrs where actuation and release time are equal and short enough with no release oscillations. Three pressure regimes are identified with characteristic behavior of the Q-factor and actuation and release time in each regime. These behaviors have significant implications in many MEMS devices, especially RF MEMS switches.

Experimental Study on the Desalination System Using Humidification-Dehumidification Technology

2020 ◽  
Vol 1008 ◽  
pp. 177-185
Author(s):  
Hamed Abbady ◽  
Mahmoud Salem Ahmed ◽  
Hamdy Hassan ◽  
A.S.A. Mohamed
Keyword(s):  
Water Temperature ◽  
Water Flow ◽  
Flow Rate ◽  
Water Flow Rate ◽  
Cooling Water ◽  
Operating Conditions ◽  
Outlet Temperature ◽  
Major Objective ◽  
Cooling Water Flow Rate ◽  
Output Ratio

In this paper, an experimental work studies the principal operating parameters of a proposed desalination process using air humidification-dehumidification method. The major objective of this work is to determine the humid air behavior through the desalination system. Different operating conditions including the effect of the water temperature at the entry to the humidifier, the ratio of the mass of water to the air, the air/water flow rate, and cooling water at entry the dehumidifier on the desalination performance were studied. The results show that the freshwater increases with increasing the water temperature at the inlet of the humidifier, the ratio of the mass of water to air, and cooling water flow rate in the dehumidifier. Cooling water outlet temperature at the condenser increases with increasing the water temperature at humidifier inlet. Also, it decreases as increasing cooling water flow rate while the ratio of the mass of water to air achieves the highest productivity and gained output ratio (GOR). The achieved mass ratio (MR) is 4.5 and the mass flow rate of air is 0.8 kg/min.

The Application of Genetic Algorithm on the Regulation of Central Heating System

2014 ◽  
Vol 672-674 ◽  
pp. 1712-1716
Author(s):  
Lin Hua Zhang ◽  
Dong Yang ◽  
Ling Liu ◽  
Ting Ting Chen
Keyword(s):  
Genetic Algorithm ◽  
Water Temperature ◽  
Water Flux ◽  
District Heating ◽  
Heating System ◽  
Flux Analysis ◽  
Flow Adjustment ◽  
Operational Optimization ◽  
Set Up ◽  
Supply Water

For the operational optimization problem of supply temperature and flow adjustment (known as “quality-quantity” regulation) in district heating system.To meet user needs hot,an operational cost equation of primary network is set up, taking the supply water temperature and the water flux as variables. The optimization objective of this equation is to minimize operational cost.Based on the genetic algorithm,and finally get the optimal water temperature and water flux. Analysis the several regulation of supply water temperature and water flux, finally proposed heating system integrated regulation.

scholarly journals Investigation of the influence of operation conditions on the discharge of PCM ceiling panels.

2019 ◽  
Vol 111 ◽  
pp. 03021
Author(s):  
José Quesada Allerhand ◽  
Ongun Berk Kazanci ◽  
Bjarne W. Olesen
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Thermal Environment ◽  
Water Discharge ◽  
Water Flow Rate ◽  
Water Circulation ◽  
Operating Conditions ◽  
Cooling Period ◽  
Operation Conditions ◽  
Office Rooms

The aim of this study was to determine favorable operation conditions for ceiling panels containing phase change materials (PCM) for cooling applications in office rooms. A recently renovated room in the Technical University of Denmark was used to have realistic boundary conditions. Using TRNSYS 17, the performance of the PCM panels during the cooling season in passive operation, discharge by air, and discharge by water circulation were investigated. A set of simulations were performed during a representative week in the cooling period. The room was simulated with no climatic systems, PCM without active discharge, ventilation during occupied hours only, and PCM with ventilation during occupied hours. Afterwards, two discharge methods were investigated, night ventilation at different flow rates and water circulation in pipes embedded in the panels. A parametric analysis was performed to identify the influence of operation factors in the thermal environment of the room. The parameters studied were the water flow rate, supply water temperature and circulation schedule as well as the conductivity of the PCM. After selecting different operating conditions of the water discharge, simulations were performed from May to October to observe the performance of the selected operation conditions. The results show that the PCM is more effective to provide adequate indoor thermal conditions if it is discharged actively by means of water. The parameters that affect the thermal indoor environment the most are the water circulation schedule, the water supply temperature, and the PCM thermal conductivity. The water flow rate did not have a significant influence. The study shows the importance of selecting an appropriate operation and control strategy for the PCM system. The process used in the study can be potentially used as a procedure for the design of similar climatic systems to determine if active discharge of the PCM is needed and if yes, which discharge method is needed.

Heating Systems

2019 ◽  
pp. 283-307
Author(s):  
Teodora Melania Şoimoşan ◽  
Raluca Andreea Felseghi ◽  
Maria Simona Răboacă ◽  
Constantin Filote
Keyword(s):  
Fossil Fuels ◽  
Energy Use ◽  
Renewable Energy Sources ◽  
Heating System ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Energy Sources ◽  
Total Energy Consumption ◽  
Heating Systems ◽  
Heating And Cooling

Within the current context of energy, there are several ways to meet the challenges of durable development. Efficiency in energy use, considered to be the fifth energy source, as well as the use of sustainable energy sources represent critical objectives. Nowadays, almost 50% of the total energy consumption in Europe is consumed by building heating and cooling. The current heat demand is mainly covered by conventional energy—fossil fuels. Consequently, there is a significant growth potential for the use of renewable energy sources (RES) in order to produce heat. One can expect in the near future that the energy systems would include a larger percentage of renewable sources, so the increase of the RES share is one of the main objectives of the thermoenergetic field. This chapter approaches heating system typology, the performance indicators used to asses the hybrid heating systems, and at the same time synthetising the assumptions of ensuring the optimum operating conditions.

scholarly journals Solar Desalination by Humidification-Dehumidification of Air

2018 ◽  
Vol 149 ◽  
pp. 02092 ◽  
Author(s):  
J. Moumouh ◽  
M. Tahiri ◽  
L. Balli
Keyword(s):  
Water Temperature ◽  
Flow Rate ◽  
Energy Use ◽  
Mechanical Energy ◽  
Water Flow Rate ◽  
Operating Conditions ◽  
Water Desalination ◽  
Arid Zones ◽  
Transfer Coefficients ◽  
System Productivity

The importance of supplying potable water can hardly be overstressed. In many arid zones, coastal or inlands, seawater or brackish water desalination may be the only solution to the shortage of fresh water. The process based on humidification-dehumidification of air (HDH) principle mimic the natural water cycle. HDH technique has been subjected to many studies in recent years due to the low temperature, renewable energy use, simplicity, low cost installation and operation. An experimental test set-up has been fabricated and assembled. The prototype equipped with appropriate measuring and controlling devices. Detailed experiments have been carried out at various operating conditions. The heat and mass transfer coefficients have been obtained experimentally. The results of the investigation have shown that the system productivity increases with the increase in the mass flow rate of water through the unit. Water temperature at condenser exit increases linearly with water temperature at humidifier inlet and it decreases as water flow rate increases. HDH desalination systems realised on also work at atmospheric pressure; hence they do not need mechanical energy except for circulation pumps and fans. These kinds of systems are suitable for developing countries. The system is modular, it is possible to increase productivity with additional solar collectors and additional HDH cycles.

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