scholarly journals Globally Optimal Synthesis of Heat Exchanger Networks.Part III:Non-isothermal Mixing in Minimal and Non-Minimal Networks

2021 ◽  
Author(s):  
Chenglin Chang ◽  
Zuwei Liao ◽  
André Costa ◽  
Miguel Bagajewicz
Keyword(s):  
Energy Consumption ◽  
Heat Exchanger ◽  
Search Algorithm ◽  
Global Optimum ◽  
Mixing Model ◽  
Optimal Synthesis ◽  
Convex Model ◽  
New Models ◽  
Enumeration Algorithms ◽  
Isothermal Mixing

In this work, the enumeration algorithms presented in parts I and II for the globally optimal synthesis of heat exchanger networks are extended to consider non-isothermal mixing. The previous models are modified by adding non-isothermal mixing constraints and new models are constructed to target the bounds of the energy consumption and the binding exchanger minimum approximation temperature. These new models are solved using algorithms that involve solving the solution of systems of equations instead of mathematical programming. We also present two alternatives for optimizing each enumerated structure, namely, the use of a global solver, or the use of a golden search with simple resolution of non-isothermal mixing model for fixed energy consumption. The non-isothermal mixing model is reformulated as a convex model, either solved using nonlinear programming or a programming-free methodology, i.e. solving Karush-Kuhn-Tucker equations. A global optimum search algorithm is developed and examples are tested comparing the proposed strategies.

scholarly journals Heat Exchanger Network Retrofit of an Oleochemical Plant through a Cost and Energy Efficiency Approach

2021 ◽  
Vol 5 (2) ◽  
pp. 17
Author(s):  
Valli Trisha ◽  
Kai Seng Koh ◽  
Lik Yin Ng ◽  
Vui Soon Chok
Keyword(s):  
Energy Consumption ◽  
Heat Exchanger ◽  
Cost Effective ◽  
Capital Cost ◽  
Global Market ◽  
Annual Saving ◽  
Heat Exchanger Network ◽  
First Case ◽  
Payback Time ◽  
Better Than

Limited research of heat integration has been conducted in the oleochemical field. This paper attempts to evaluate the performance of an existing heat exchanger network (HEN) of an oleochemical plant at 600 tonnes per day (TPD) in Malaysia, in which the emphases are placed on the annual saving and reduction in energy consumption. Using commercial HEN numerical software, ASPEN Energy Analyzer v10.0, it was found that the performance of the current HEN in place is excellent, saving over 80% in annual costs and reducing energy consumption by 1,882,711 gigajoule per year (GJ/year). Further analysis of the performance of the HEN was performed to identify the potential optimisation of untapped heating/cooling process streams. Two cases, which are the most cost-effective and energy efficient, were proposed with positive results. However, the second case performed better than the first case, at a lower payback time (0.83 year) and higher annual savings (0.20 million USD/year) with the addition of one heat exchanger at a capital cost of USD 134,620. The first case had a higher payback time (4.64 years), a lower annual saving (0.05 million USD/year) and three additional heaters at a capital cost of USD 193,480. This research has provided a new insight into the oleochemical industry in which retrofitting the HEN can further reduce energy consumption, which in return will reduce the overall production cost of oleochemical commodities. This is particularly crucial in making the product more competitive in its pricing in the global market.

Lower limb exoskeleton robots’ dynamics parameters identification based on improved beetle swarm optimization algorithm

Robotica ◽  
2022 ◽  
pp. 1-16
Author(s):  
Peng Zhang ◽  
Junxia Zhang
Keyword(s):  
Optimization Algorithm ◽  
Robot Control ◽  
Search Algorithm ◽  
Optimal Solution ◽  
Global Optimum ◽  
Identification Accuracy ◽  
Dynamic Parameters ◽  
Dynamics Modeling ◽  
Swarm Optimization ◽  
Exoskeleton Robot

Abstract Efficient and high-precision identification of dynamic parameters is the basis of model-based robot control. Firstly, this paper designed the structure and control system of the developed lower extremity exoskeleton robot. The dynamics modeling of the exoskeleton robot is performed. The minimum parameter set of the identified parameters is determined. The dynamic model is linearized based on the parallel axis theory. Based on the beetle antennae search algorithm (BAS) and particle swarm optimization (PSO), the beetle swarm optimization algorithm (BSO) was designed and applied to the identification of dynamic parameters. The update rule of each particle originates from BAS, and there is an individual’s judgment on the environment space in each iteration. This method does not rely on the historical best solution in the PSO and the current global optimal solution of the individual particle, thereby reducing the number of iterations and improving the search speed and accuracy. Four groups of test functions with different characteristics were used to verify the performance of the proposed algorithm. Experimental results show that the BSO algorithm has a good balance between exploration and exploitation capabilities to promote the beetle to move to the global optimum. Besides, the test was carried out on the exoskeleton dynamics model. This method can obtain independent dynamic parameters and achieve ideal identification accuracy. The prediction result of torque based on the identification method is in good agreement with the ideal torque of the robot control.

Application of the Tabu Search Algorithm on Solving the Optimum Heating Institution of Reheating Furnace

2011 ◽  
Vol 130-134 ◽  
pp. 1725-1729
Author(s):  
Ye Jian Yang ◽  
Ze Yi Jiang ◽  
Xin Xin Zhang ◽  
Peng Jin
Keyword(s):  
Mathematical Model ◽  
Energy Consumption ◽  
Tabu Search ◽  
Search Algorithm ◽  
Tabu Search Algorithm ◽  
Reheating Furnace ◽  
Consumption Cost ◽  
Optimum Heat ◽  
Heating Model ◽  
Oxidation Loss

With the aim of minimizing the energy consumption cost and taking the billet heating quality as the constraint condition, a mathematical model was established based on the billet heating model to solve the optimum heat institution of the reheating furnace. The tabu search algorithm was employed to solve the model. The results of the industrial production data optimization showed that the proposed mathematical model and the solving method could fully meet the practical production demand of the reheating furnace. In addition to satisfying the heating quality requirements, the energy consumption is reduced and the oxidation loss is decreased. Compared with the original one, the heating institution obtained from the mentioned model and algorithm had a better performance on energy efficiency.

Reactive Power Compensation of Oilfield Distribution Systems Based on Tabu Search Algorithm

2013 ◽  
Vol 397-400 ◽  
pp. 1113-1116
Author(s):  
Xiao Meng Wu ◽  
Wang Hao Fei ◽  
Xiao Mei Xiang ◽  
Wen Juan Wang
Keyword(s):  
Power Loss ◽  
Distribution Systems ◽  
Reactive Power ◽  
Search Algorithm ◽  
Global Optimum ◽  
Reactive Power Compensation ◽  
Active Power ◽  
Voltage Profile ◽  
Voltage Range ◽  
Shunt Capacitors

In order to solve the problem in reactive power compensation of oilfield distribution systems at present, a Taboo search algorithm is proposed in this paper, by which the optimal location and size of shunt capacitors on distribution systems are determined. Then the voltage profile is improved and the active power loss is reduced. In this paper, Voltage qualified is used as objective function to search an initial solution that meets the voltage constraints so that it is feasible in practicable voltage range; then the global optimum solution can be got when taking the reduced maximum of active power loss as objective unction. The examples show that the improved algorithm is feasible and effective.

scholarly journals Yearly Cost Saving by Using Enthalpy Heat Exchanger During Cooling and Heating

2020 ◽  
Vol 328 ◽  
pp. 01014
Author(s):  
Kamil Križo ◽  
Andrej Kapjor ◽  
Martin Vantúch
Keyword(s):  
Energy Consumption ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Building Energy ◽  
Sensible Heat ◽  
Oxygen Level ◽  
Optimal Temperature ◽  
Air Handling Unit ◽  
Save Energy ◽  
Yearly Cost

Fresh air has to be constantly supplied to the building by air handling unit, where supplied air is mixed with inside air and optimal temperature, oxygen level is adjusted and level of dust and smoke is reduced. Supply air demand of the building is determined according to number of persons in the room, room area and regulations. Necessity of ventilation rely in supplying room with oxygen, cleaning the air, adjusting temperature and moisture and reduction of odours, gases, dust, bacteria and viruses. Achieving optimal properties of supply air creates huge portion of building energy consumption. To save energy during ventilation, standard air to air sensible heat exchangers are used. They purpose is to recover sensible heat from exhaust air and at the same time avoid contamination of supply air. Drawback of these types of exchangers is limit of recovering moisture, therefore huge portion of energy in form of latent heat is lost. On top of classical plate air to air heat exchanger, enthalpy heat exchanger allows to exchange latent as well as sensible heat [1].

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