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![Fig. 1: Schematic diagram of the centrifugal chiller system [?].](profile/Abhisek-Ukil/publication/330081729/figure/fig1/AS:710545661497344@1546418695243/Schematic-diagram-of-the-centrifugal-chiller-system_Q320.jpg)
![Fig. 4: IE efficiency classes for 4 pole motors at 50 Hz [21].](profile/Abhisek-Ukil/publication/330081729/figure/fig4/AS:710545661509636@1546418695426/E-efficiency-classes-for-4-pole-motors-at-50-Hz-21_Q320.jpg)
![Fig. 5: Comparison of construction and losses of IM and SynRM [26].](profile/Abhisek-Ukil/publication/330081729/figure/fig5/AS:710545661509637@1546418695483/Comparison-of-construction-and-losses-of-IM-and-SynRM-26_Q320.jpg)
A significant portion (ca. 40%) of the world's total energy is utilized in buildings. Cooling of large buildings worldwide is done by centrifugal chiller systems, where the compressors, pumps, fans are driven by AC motors. These motors are energy hungry parts of the chiller. All-variable speed chillers, taking into account load variations, reduced...
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Heating, ventilation, and air-conditioning (HVAC) systems usually have a set-point temperature control feature that uses the indoor dry-bulb temperature to control the indoor environment. However, an incorrect set-point temperature can reduce thermal comfort and result in unnecessary energy consumption. This study focuses on a derivation method for...
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... However, the lack of price stability of the rare earth elements used for the production of neodymiumbased magnets has forced researchers and industry to search for alternatives [1]. Among the proposed rare-earth-free alternative machine topologies, Synchronous Reluctance Motors (RSMs) are gaining popularity, and they are gradually forcing the asynchronous machines out of the inverter-fed drives market due to their superior efficiency and simpler rotor construction [2]. ...
Machines with highly saturated magnetic circuits are utilized to maximize drive efficiency. However, their control is non-trivial due to highly non-linear characteristics, and therefore, an accurate parameter identification procedure is crucial. This paper presents and validates a comprehensive flux linkage identification procedure. Several steps needed for accurate parameter identification and their influence on the estimation results are described. The impact of all main parts of the electrical drive, i.e., dead times introduced between switching off and switching on the power transistors, phase delay from the current low-pass filters, delay from the control system, and misalignment of the d–axis angle due to the machine asymmetries is considered and partially eliminated. An improved identification procedure with the look-up table-based dead time compensation and estimation of equivalent circuit resistance is applied to estimate the parameters of the highly saturated PMSM traction machine from the fourth generation of the Toyota Prius, and the obtained results are compared with a Finite Element Method-based model of this machine. Finally, dynamic test results are conducted to prove the proposed approach’s accuracy.
... This is achieved by estimating the potential emission savings when one unit of the proposed GCCPS is installed. The calculation assumes a coefficient of performance (COP) of 4.0 for the conventional chiller, which falls within the typical COP range of 3.5 to 5 [59]. A grid emission factor (GEF) of 784 g CO 2 eq/kWh is taken, reflecting the present GEF of Indonesia [60]. ...
... However, IM efficiency declines significantly in partial-load conditions, making VSDPs a necessary alternative. In addition, SRMs can offer higher energy efficiency in VSDP applications, especially in systems such as chillers, where they have the potential to replace IMs [29]. The effectiveness of these technological advancements is strongly influenced by energy policies, which have driven industrial energy efficiency initiatives. ...
... Although many authors have recently focused on the energy efficiency of pump drives, a systematic approach to modelling the entire VSDP with detailed consideration of all its components is still difficult to find. Most research focuses on a specific component of the VSDP, e.g., the design of the impeller blades [14], the shape of the inlet pipe [15], or the selection of the optimal motor type [16,17,19,29]. Many of these studies also consider ...
... This fragmented approach often fails to capture the complex interactions within the entire system. Some recent studies have investigated the efficiency of the converter, motor, pump, and the entire system at different water flows [26], or compared energy consumption between IM and SRM motor types at different speeds and loads [18,19,29]. However, these studies do not comprehensively cover several pump types simultaneously and do not provide a complete map of operating efficiency. ...
Outdated, oversized variable speed pump drives (VSDPs) in industry lead to sub-optimal energy efficiency and considerable energy losses. This paper proposes methods to develop 2D efficiency maps for motors, converters, and pumps using polynomial surface fitting, which enables efficiency evaluation in a wide operating range. The method was applied to an oversized VSDP in an industrial chilled water supply system, comparing the original system with five alternative VSDP combinations with high-efficiency motors and pumps. The five VSDP variants demonstrated average energy savings of around 30%, with the synchronous reluctance motor (SRM) configurations outperforming the induction motor (IM) configurations by up to 7 percentage points, particularly at low loads. The high-efficiency SRM-based 252-IE5 variant delivered the best overall energy performance, highlighting the benefits of optimised system sizing and motor selection for energy savings. The proposed method can be used in both industrial and residential applications and offers great advantages in process systems that require variable flow and pressure of water or other fluids during operation, such as HVAC, water supply and wastewater treatment, district heating, etc. The development of a VSDP drive with efficient energy optimisation is an interdisciplinary problem of mechanical and electrical engineering, and without the interaction of engineers from both fields the result will not be optimal. We try to present our method so that it can be a reliable tool for mechanical, electrical, and other engineers or researchers to assist them in finding possible energy savings, performing energy audits, and selecting the most suitable components when modernising existing or developing new systems.
... The speed of machines used in driving loads within this system can be controlled for an effective response, and this can also improve system efficiency [13,14,15,16,17]. Technologies have made it possible to achieve efficient speed control with vector control technique long with nonlinear [18][19][20][21]. Where conventional controllers like PID and nonlinear controllers like fuzzy logic and sliding mode and so on are employed to a realistic specific speed requirement in a given operating condition. ...
... The model gave an improved response when compared to either fuzzy logic or PID controller. In Oliveira and Uki [19], dynamic response using a fuzzy logic controller (FLC) was compared with a proportional integral (PI) controller; the latter showed superior performance at low speed. Umoette et al. [4] presented variable refrigerant flow (VRF) technology using variable speed drives. ...
Induction motor (IM) is the most used AC machine, and it is a constant speed device. If induction motion must be used in variable speed applications, its speed must be controlled. Speed control of a squirrel cage induction motor (SCIM) using a control algorithm with proportional integral derivative (PID) and sliding mode controller (SMC) was designed, simulated, and analyzed in this paper. Three-phase SCIM was considered, MATLAB software was used for both design and simulation and decoupling of the flux and torque-producing components for separate control was done for the actual control of the SCIM drive. The motor drive was used in driving a constant load of 0% (0 Nm), 28% (4 Nm), and 62% (12 Nm) of the rated torque with a variable speed of 0 rad/s, 10 rad/s, and 25 rad/s. It is observed that SMC gave the best speed performance compared to other controllers. The steady-state error, rise time, settling time, and overshoot of the SMC model were 0.1%, 0.01 sec, 0.05 sec, and 4%, respectively while that if PID were respectively 2 %, 0.02 sec, 0.2 sec, and 16 %, when driving 4Nm under intermittent speed. The improved speed performance of the proposed SM controller can be used in robotics where high precision speed performance is required.
... Technologies have made it possible to achieve efficient speed control with vector control techniques along with artificial and hybrid controllers in variable applications [10][11][12][13]. Control of IM behavior has been developed over the years, tailored to a lot of modern industrial operations. ...
... For example, [4] revealed that adequate speed control is required for proper energy management and efficiency improvement in the central chiller system. In [11], dynamic response using a fuzzy logic controller (FLC) was compared with a proportional integral (PI) controller, which showed superior performance at low speed. [5] presented variable refrigerant flow (VRF) technology using variable speed drives. ...
Speed control of a squirrel cage induction motor (SCIM) using a novel control algorithm with proportional integral derivative (PID), fuzzy logic (FL) controller, hybrid controller (FL-PID), and optimized hybrid controller (FL-PID-PSO) was designed, simulated, and analyzed in this paper. 2.5kW three-phase SCIM was considered, and decoupling of the flux and torque-producing components for separate control was done for the actual control of the SCIM drive. The motor drive was used to drive a constant load of 0% (0 Nm), 50% (7 Nm), and 80% (12 Nm) of the rated torque with a variable speed of 0 rpm, 15 rpm, and 30 rpm. It was observed that FL-PID-PSO gave the best speed performance compared to other controllers. The steady-state error, rise time, settling time, overshot, and undershoot of the proposed model were 0.04 rpm, 0.01 sec, 0.02 sec, 0.06%, and 0%, respectively, when driving 12 Nm at intermittent speed. The improved speed performance of the proposed FL-PID-PSO controller can be used in robotics where high precision speed performance is required.
... While the application of optimization algorithms in improving operational efficiency of chiller plants has been explored [26]- [36], significant gaps remain in their adaptation to real-time dynamic environments. Current methodologies often fail to fully integrate fluctuating environmental and operational parameters, which are crucial for the sustainable management of energy resources in industrial settings. ...
This study aims to enhance operational efficiency in chiller plants by implementing the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm. The primary objectives are to simultaneously reduce energy consumption and increase cooling efficiency, addressing the challenges posed by variable environmental and operational conditions. Employing the MOPSO algorithm, this research conducts a detailed analysis using real-time environmental data and operational parameters. This approach facilitates a dynamic adaptation to changes in ambient temperature and electricity pricing, ensuring that the algorithm's application remains effective under fluctuating conditions. The application of MOPSO has resulted in significant reductions in energy use and improvements in cooling efficiency. These results demonstrate the algorithm's capacity to optimize chiller plant operations dynamically, adapting to changes in environmental conditions and operational demands. The study finds that MOPSO's adaptability to dynamic operational conditions enables robust energy management in chiller plants. This adaptability is crucial for maintaining efficiency and cost-effectiveness in industrial applications, especially under varying environmental impacts. The paper contributes to the field by enhancing the understanding of how advanced optimization algorithms like MOPSO can be effectively integrated into energy management systems for chiller plants. A novel aspect of this research is the integration of real-time data analytics into the optimization process, which significantly improves the sustainability and operational efficiency of HVAC systems. Furthermore, the study outlines the potential for similar research applications in large-scale HVAC systems, where such algorithmic improvements can extend practical benefits. The findings underscore the importance of considering a broad range of environmental and operational factors in the optimization process and suggest that MOPSO's flexibility and robustness make it a valuable tool for achieving sustainable and cost-effective energy management in industrial settings.
... Its manufacturing cost is about 15÷20% lower, and the efficiency is up to 4% better than that of a squirrel cage induction motor (SCIM) [1]. Thus, the RSM drives become popular in such industrial applications as pumps, fans, compressors [3], lift traction [4], and finally, electric vehicles (EVs) [5]. The proper selection of a drive system is application-driven; among several criteria like dynamics, robustness, and efficiency, another criterion becomes important, i.e., acoustic noise generation [6], especially in the EVs area. ...
... Since the operation principle of RSMs is based on the magnetic reluctance phenomenon, no eddy currents are produced for rotor excitation, in contrast to SCIMs [3,7]. Thus, a specific salient pole rotor construction is necessary, which ensures energy-effective operation [1,7]. ...
This article discusses an identification and modeling approach of a reluctance synchronous motor (RSM) based on the running rotor technique. The applied flux linkage approximation functions reflect the self-saturation and cross-saturation effects, and the applied mathematical model is continuous and differentiable. The proper design of the experiment is discussed, and relevant recommendations are made to ensure the mitigation of procedural mistakes in the experiments. A detailed analysis of the impact of configuration faults on the obtained experimental data is provided, considering distortions in the obtained flux linkage and inductance surfaces. Considering the achieved model accuracy, a novel model evaluation considering the achieved model accuracy technique based on transient current response is proposed.
... E FFICIENCY enhancement has become an essential topic in electrical engineering due to increasing environmental concerns, worldwide power demand growth, the depletion of non-renewable energy resources, and the impact on electric vehicles [1]. Synchronous reluctance motors (SynRM) are particularly notable, known for their robust construction and absence of rare-earth magnets, and are widely used in industrial applications; therefore, improvements in their efficiency can significantly reduce overall energy consumption. ...
In pursuit of improving energy efficiency in the industry, this paper proposes two model-based loss-minimization techniques for synchronous reluctance motors (SynRM): the model-based loss-minimization robust method (MLR) and the simplified model-based loss-minimization robust method (SMLR). Both techniques belong to the broader category of model-based methods, which are known for their fast dynamic convergence, low torque ripple, and reduced computational load compared to search-based and hybrid methods. Results reveal that both MLR and SMLR exhibit appropriate performance against motor parameter variations, particularly in the components of stator inductance (
Ldq
), while maintaining high efficiency and minimal power loss. The study paves the way for the integration of these techniques into control strategies that use active flux to further enhance the efficiency of SynRM in industrial applications. The paper presents a comprehensive and thorough sensitivity analysis, along with detailed experimental results, that effectively verify the proper and consistent performance of the proposed methods across various operating points.
... ECWT also showed an improvement after the servicing process where there is a decreasing entering temperature value as in Figure 12. Therefore, understanding the FLA and current usage of a cooling tower can help to optimize its energy efficiency and reduce operating costs (Oliveira & Ukil, 2019). ...
This paper presents the result of a study of the effect of cooling tower system in terms of performance and cost of maintenance. The study was conducted in a two-storey shopping complex building. Observation on site was held to obtain data on full load amp (FLA) and chilled water temperature (CWT) before and after servicing cooling tower unit. Energy of cooling tower were evaluated by analysis of FLA and CWT in percentage value. The condition on the system and component were also observed to differentiate the condition before and after treatment. The result obtained showed that cooling system performance after the treatment was increased.
... Its manufacturing cost is about 15÷20% lower, and the efficiency is up to 4% better than that of a squirrel cage induction motor (SCIM) [1]. Thus, the RSM drives become popular in such industrial applications as pumps, fans, compressors [3], lift traction [4], and finally, electric vehicles (EVs) [5]. ...
... Since the operation principle of RSMs is based on the magnetic reluctance phenomenon, no eddy currents are produced for rotor excitation, in contrast to SCIMs [3,6]. Thus, a specific salient pole rotor construction is necessary, which ensures energy-effective operation [1,6]. ...
The paper presents a practical approach for identifying and dynamic modeling reluctance synchronous motor’s (RSM) electrical circuit. The mathematical modeling for the electrical circuit is provided in a current-based state-space representation. The flux linkage estimation technique with assumed approximation functions is discussed, emphasizing proper experimental data collection. The quality of the developed model is investigated using static approximation and current transient response.
