Research

3832 KiB

Open AccessArticle

A Grey-Box Dynamic Model of Plate Heat Exchangers Used in an Urban Heating System

by Qingwei Miao, Shijun You, Wandong Zheng, Xuejing Zheng, Huan Zhang and Yaran Wang

Energies 2017, 10(9), 1398; https://doi.org/10.3390/en10091398 - 13 Sep 2017

Cited by 15 | Viewed by 7654

This paper deals with the establishment of a grey-box model of plate heat exchangers. First, a second-order state space model of plate heat exchangers is developed. Then, the model is solved by the white-box method and grey-box method, respectively. In the white-box method, [...] Read more.

This paper deals with the establishment of a grey-box model of plate heat exchangers. First, a second-order state space model of plate heat exchangers is developed. Then, the model is solved by the white-box method and grey-box method, respectively. In the white-box method, the linearization of the state space model is carried out by implicit difference scheme and the overall heat transfer coefficient was calculated with empirical correlation of the Nusselt number. In the grey-box method, a newly developed parameter identification method was established. The simulation results of two outlet temperatures by the grey-box and white-box method, respectively, are compared with the test data. It is shown that the grey-box method is more suitable and accurate for the simulations of outlet temperatures than the white-box method. Thus, it can provide practitioners and heating engineers with tools to design controllers for district heating systems. Full article

(This article belongs to the Special Issue Energy Management Control)

► Show Figures

Figure 1

412 KiB

Open AccessArticle

Evaluation of Demand-Side Management over Pricing Competition of Multiple Suppliers Having Heterogeneous Energy Sources

by Kireem Han, Joohyung Lee and Junkyun Choi

Energies 2017, 10(9), 1342; https://doi.org/10.3390/en10091342 - 05 Sep 2017

Cited by 12 | Viewed by 3362

Abstract

This study investigates a demand-side management problem in which multiple suppliers compete with each other to maximize their own revenue. We consider that suppliers have heterogeneous energy sources and individually set the unit price of each energy source. Then, consumers that share a [...] Read more.

This study investigates a demand-side management problem in which multiple suppliers compete with each other to maximize their own revenue. We consider that suppliers have heterogeneous energy sources and individually set the unit price of each energy source. Then, consumers that share a net utility react to the suppliers’ decisions on prices by deciding the amount of energy to request, or how to split the consumers’ aggregated demand over multiple suppliers. In this case, the consumers need to consider the power loss and the price to pay for procuring electricity. We analyze the economic benefits of such a pricing competition among suppliers (e.g., a demand-side management that considers consumers’ reaction). This is achieved by designing a hierarchical decision-making scheme as a multileader–multifollower Stackelberg game. We show that the behaviors of both consumers and suppliers based on well-designed utility functions converge to a unique equilibrium solution. This allows them to maximize the payoff from all participating consumers and suppliers. Accordingly, closed-form expressions are provided for the corresponding strategies of the consumers and the suppliers. Finally, we provide numerical examples to illustrate the effectiveness of the solutions. This game-theoretic study provides an example of incentives and insight for demand-side management in future power grids. Full article

(This article belongs to the Special Issue Energy Management Control)

► Show Figures

Figure 1

5935 KiB

Open AccessArticle

A Novel Method for Idle-Stop-Start Control of Micro Hybrid Construction Equipment—Part B: A Real-Time Comparative Study

by Truong Quang Dinh, James Marco, Hui Niu, David Greenwood, Lee Harper and David Corrochano

Energies 2017, 10(9), 1250; https://doi.org/10.3390/en10091250 - 23 Aug 2017

Cited by 3 | Viewed by 5442

Abstract

Micro hybrid propulsion (MHP) technologies have emerged as promising solutions for minimisation of fuel consumption and pollutant emissions of off-highway construction machines (OHCMs). Their performance and economic feasibility strongly depend on the way they utilize the idle-stop-start control (ISSC) concept. The ISSC design [...] Read more.

Micro hybrid propulsion (MHP) technologies have emerged as promising solutions for minimisation of fuel consumption and pollutant emissions of off-highway construction machines (OHCMs). Their performance and economic feasibility strongly depend on the way they utilize the idle-stop-start control (ISSC) concept. The ISSC design process and performance evaluation are particularly challenging due to the peculiar structures and dynamics of OHCMs compared to other vehicles and, therefore, require significant development time and efforts. This paper is the second of a two-part study focusing on prediction-based idle-start-stop control (PISSC) for micro hybrid OHCMs. In part A, the powertrain model and the procedure to design the PISSC system have been presented. The PISSC-based engine control performance has been investigated through numerical simulations with the designed model. In this Part B, a hardware-in-the-loop (HIL) test platform is established in HIL Control Laboratory for the rapid validation of the proposed technique in terms of the fuel/pollutant emission saving in real-time. First, the powertrain architecture and PISSC algorithm presented in Part A are briefly reviewed. Second, the process to build the HIL test platform is clearly stated. Third, experiments and analysis are carried out for a number of comparative studies to validate the superiority and practical applicability of the PISSC approach. Full article

(This article belongs to the Special Issue Energy Management Control)

► Show Figures

Figure 1

10431 KiB

Open AccessArticle

Reduction of Stress Acting on a Thick, Deep Coal Seam by Protective-Seam Mining

by Rui Gao, Bin Yu, Hongchun Xia and Hongfei Duan

Energies 2017, 10(8), 1209; https://doi.org/10.3390/en10081209 - 15 Aug 2017

Cited by 25 | Viewed by 4218

Abstract

Aiming to reduce the high mining stress observed in large-space roof structures during mechanized mining of thick coal seams, a control technique based on protective-seam mining is proposed. This technique was used to investigate the 8108 working face of the No. 3–5 thick [...] Read more.

Aiming to reduce the high mining stress observed in large-space roof structures during mechanized mining of thick coal seams, a control technique based on protective-seam mining is proposed. This technique was used to investigate the 8108 working face of the No. 3–5 thick coal seam of the Tashan mine located in the Datong area of Shanxi, China, by means of simulations and field measurements. The numerical simulation revealed that the No. 3–5 coal seam undergoes expansion and deformation, accompanied by stress relief due to the mining of the overlying No. 4 coal seam. The physical simulation demonstrated that mining the protective seam changes the structural characteristics of the overlying strata in advance and reduces the integrity of the roof in the No. 3–5 coal seam. Field measurements showed that the support loads in the 8108 working face are significantly weaker than those in the adjacent 8107 working face, where protective-seam mining was not performed. In the absence of high resistance on the support and distinct periodic weighting characteristics, the rock masses around the 8108 working face and roadway could be easily supported. Full article

(This article belongs to the Special Issue Energy Management Control)

► Show Figures

Figure 1

1115 KiB

Open AccessArticle

Real-Time Distributed Economic Model Predictive Control for Complete Vehicle Energy Management

by Constantijn Romijn, Tijs Donkers, John Kessels and Siep Weiland

Energies 2017, 10(8), 1096; https://doi.org/10.3390/en10081096 - 27 Jul 2017

Cited by 9 | Viewed by 4803

Abstract

In this paper, a real-time distributed economic model predictive control approach for complete vehicle energy management (CVEM) is presented using a receding control horizon in combination with a dual decomposition. The dual decomposition allows the CVEM optimization problem to be solved by solving [...] Read more.

In this paper, a real-time distributed economic model predictive control approach for complete vehicle energy management (CVEM) is presented using a receding control horizon in combination with a dual decomposition. The dual decomposition allows the CVEM optimization problem to be solved by solving several smaller optimization problems. The receding horizon control problem is formulated with variable sample intervals, allowing for large prediction horizons with only a limited number of decision variables and constraints in the optimization problem. Furthermore, a novel on/off control concept for the control of the refrigerated semi-trailer, the air supply system and the climate control system is introduced. Simulation results on a low-fidelity vehicle model show that close to optimal fuel reduction performance can be achieved. The fuel reduction for the on/off controlled subsystems strongly depends on the number of switches allowed. By allowing up to 15-times more switches, a fuel reduction of 1.3% can be achieved. The approach is also validated on a high-fidelity vehicle model, for which the road slope is predicted by an e-horizon sensor, leading to a prediction of the propulsion power and engine speed. The prediction algorithm is demonstrated with measured ADASIS information on a public road around Eindhoven, which shows that accurate prediction of the propulsion power and engine speed is feasible when the vehicle follows the most probable path. A fuel reduction of up to 0.63% is achieved for the high-fidelity vehicle model. Full article

(This article belongs to the Special Issue Energy Management Control)

► Show Figures

Figure 1

5054 KiB

Open AccessArticle

A Novel Method for Idle-Stop-Start Control of Micro Hybrid Construction Equipment—Part A: Fundamental Concepts and Design

by Truong Quang Dinh, James Marco, Hui Niu, David Greenwood, Lee Harper and David Corrochano

Energies 2017, 10(7), 962; https://doi.org/10.3390/en10070962 - 10 Jul 2017

Cited by 6 | Viewed by 5650

Abstract

Although micro hybrid propulsion (MHP) systems are recognized as a feasible solution for off-highway construction machines (OHCMs), there is still a lack of understanding how existing MHP technologies can be transferred effectively from the automotive sector to the construction sector. To fill this [...] Read more.

Although micro hybrid propulsion (MHP) systems are recognized as a feasible solution for off-highway construction machines (OHCMs), there is still a lack of understanding how existing MHP technologies can be transferred effectively from the automotive sector to the construction sector. To fill this gap, this paper is the first of a two-part study which focuses on micro hybrid construction machines paying attention to a novel idle-stop-start control (ISSC) strategy. Part A presents the system concepts and design procedure while Part B studies on a hardware-in-the-loop test platform for a comprehensive analysis on the potential fuel/emission saving of the proposed system in real-time. In this study—Part A—different types of OHCMs are briefly discussed to identify the target machine. The procedure to model the machine powertrain is also concisely introduced. Next, to minimize the fuel consumption and emissions without degrading the machine performance, a prediction-based idle-stop-start control (PISSC) approach is properly designed. The core of the PISSC is to estimate online the future engine working state changes in order to directly shut down the engine or shift it to low power regions during idle periods. Numerical simulations have been carried out to validate the potential of the proposed PISSC method. Full article

(This article belongs to the Special Issue Energy Management Control)

► Show Figures

Figure 1

2570 KiB

Open AccessArticle

Switched Control Strategies of Aggregated Commercial HVAC Systems for Demand Response in Smart Grids

by Kai Ma, Chenliang Yuan, Jie Yang, Zhixin Liu and Xinping Guan

Energies 2017, 10(7), 953; https://doi.org/10.3390/en10070953 - 09 Jul 2017

Cited by 19 | Viewed by 4027

Abstract

This work proposes three switched control strategies for aggregated heating, ventilation, and air conditioning (HVAC) systems in commercial buildings to track the automatic generation control (AGC) signal in smart grid. The existing control strategies include the direct load control strategy and the setpoint [...] Read more.

This work proposes three switched control strategies for aggregated heating, ventilation, and air conditioning (HVAC) systems in commercial buildings to track the automatic generation control (AGC) signal in smart grid. The existing control strategies include the direct load control strategy and the setpoint regulation strategy. The direct load control strategy cannot track the AGC signal when the state of charge (SOC) of the aggregated thermostatically controlled loads (TCLs) exceeds their regulation capacity, while the setpoint regulation strategy provides flexible regulation capacity, but causes larger tracking errors. To improve the tracking performance, we took the advantages of the two control modes and developed three switched control strategies. The control strategies switch between the direct load control mode and the setpoint regulation mode according to different switching indices. Specifically, we design a discrete-time controller and optimize the controller parameter for the setpoint regulation strategy using the Fibonacci optimization algorithm, enabling us to propose two switched control strategies across multiple time steps. Furthermore, we extend the switched control strategies by introducing a two-stage regulation in a single time step. Simulation results demonstrate that the proposed switched control strategies can reduce the tracking errors for frequency regulation. Full article

(This article belongs to the Special Issue Energy Management Control)

► Show Figures

Figure 1

4483 KiB

Open AccessArticle

Frequency Control Ancillary Service Provided by Efficient Power Plants Integrated in Queuing-Controlled Domestic Water Heaters

by Yebai Qi, Dan Wang, Xuyang Wang, Hongjie Jia, Tianjiao Pu, Naishi Chen and Kaixin Liu

Energies 2017, 10(4), 559; https://doi.org/10.3390/en10040559 - 19 Apr 2017

Cited by 10 | Viewed by 3931

Abstract

Frequency is an important parameter of a power system. It is of great significance to maintain its stability, especially in the current development scenario of large-scale interconnected power systems. Thermostatically controlled appliances (TCAs) are good controllable resources for demand response owing to their [...] Read more.

Frequency is an important parameter of a power system. It is of great significance to maintain its stability, especially in the current development scenario of large-scale interconnected power systems. Thermostatically controlled appliances (TCAs) are good controllable resources for demand response owing to their rapid response capabilities and relatively wide controllable ranges. In this study, domestic water heaters, which have wider deadbands compared with other typical TCAs, such as heat pumps, are used as frequency regulation resources. The main contribution of this paper is that it proposes a queuing-controlled strategy with lock-on and off constraints for controlling an efficient power plant consisting of water heaters (EPP-WH). The queuing-controlled strategy enables TCAs to provide frequency regulation ancillary service for the normal operation of the power system. The thermal dynamic process of the water heater and the formation of the EPP-WH are first discussed. Based on the developed model, a series of strategies are proposed, including load shedding calculation, top layer optimization, and improved temperature priority list (TPL) strategy with lock-on and off constraints. Finally, typical case studies are discussed to illustrate the frequency regulation effects and the effects of two characteristic parameters—users’ willingness and lock time limits. Reasonable targets are generated based on various consideration from top layer optimization module. The results indicate that using the model and proposed strategies, the EPP-WH has good frequency regulation performance. Full article

(This article belongs to the Special Issue Energy Management Control)

► Show Figures

Figure 1

563 KiB

Open AccessArticle

Performance Analysis of Data-Driven and Model-Based Control Strategies Applied to a Thermal Unit Model

by Cihan Turhan, Silvio Simani, Ivan Zajic and Gulden Gokcen Akkurt

Energies 2017, 10(1), 67; https://doi.org/10.3390/en10010067 - 07 Jan 2017

Cited by 8 | Viewed by 5351

Abstract

The paper presents the design and the implementation of different advanced control strategies that are applied to a nonlinear model of a thermal unit. A data-driven grey-box identification approach provided the physically–meaningful nonlinear continuous-time model, which represents the benchmark exploited in this work. [...] Read more.

The paper presents the design and the implementation of different advanced control strategies that are applied to a nonlinear model of a thermal unit. A data-driven grey-box identification approach provided the physically–meaningful nonlinear continuous-time model, which represents the benchmark exploited in this work. The control problem of this thermal unit is important, since it constitutes the key element of passive air conditioning systems. The advanced control schemes analysed in this paper are used to regulate the outflow air temperature of the thermal unit by exploiting the inflow air speed, whilst the inflow air temperature is considered as an external disturbance. The reliability and robustness issues of the suggested control methodologies are verified with a Monte Carlo (MC) analysis for simulating modelling uncertainty, disturbance and measurement errors. The achieved results serve to demonstrate the effectiveness and the viable application of the suggested control solutions to air conditioning systems. The benchmark model represents one of the key issues of this study, which is exploited for benchmarking different model-based and data-driven advanced control methodologies through extensive simulations. Moreover, this work highlights the main features of the proposed control schemes, while providing practitioners and heating, ventilating and air conditioning engineers with tools to design robust control strategies for air conditioning systems. Full article

(This article belongs to the Special Issue Energy Management Control)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Energy Management Control

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (9 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI