Energy-saving potential for centrifugal pump storage operation using optimized control schemes

AbstractIn this paper, we present the energy-saving potential of using optimized control for centrifugal pump–driven water storages. For this purpose, a Simulink pump-pipe-storage model is used. The equations and transfer function for steady-state and transient system behavior are presented and verified. Two different control strategies—optimum constant flow rate and level guided speed control—are compared to an allegedly optimal-driven pump with constant rotational speed. Twelve centrifugal pumps between 1 and 120 kW nominal power are evaluated to analyze the influence of different system parameters. The system characteristics, which are the static head, dynamic head factor, and maximum filling head, are varied 25 times for each pump in consideration of the pump’s best efficiency point. Thus, 300 different systems are optimized for each control strategy and compared to the constant speed control. The results are analyzed and the relevant system’s parameters, which have the most significant impact on energy savings, are shown. This theoretical energy–saving potential is verified with measurements, which show the high impact of the part load losses of the frequency converter and the electric motor. A law for identifying and estimation potential energy savings is developed using this information. Four use cases are analyzed with this law. It is shown that for a cost-minimal operation, not only the savings potential but also the operating time is decisive.

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Demand Control Strategies of a PCM Enhanced Ventilation System for Residential Buildings

Applied Sciences ◽

10.3390/app10124336 ◽

2020 ◽

Vol 10 (12) ◽

pp. 4336

Author(s):

Yue Hu ◽

Per Kvols Heiselberg ◽

Tine Steen Larsen

Keyword(s):

New York ◽

Energy Storage ◽

Energy Saving ◽

Energy Savings ◽

Control Strategies ◽

Residential Buildings ◽

Ventilation System ◽

Airflow Rate ◽

Energy Saving Potential ◽

Demand Control

A ventilated window system enhanced by phase change material (PCM) has been developed, and its energy-saving potential examined in previous works. In this paper, the ventilation control strategies are further developed, to improve the energy-saving potential of the PCM energy storage. The influence of ventilation airflow rate on the energy-saving potential of the PCM storage is firstly studied based on an EnergyPlus model of a sustainable low energy house located in New York. It shows that in summer, the optimized ventilation airflow rate is 300 m3/h. The energy-saving of utilizing a ventilated window with PCM energy storage is 10.1% compared to using a stand-alone ventilated window, and 12.0% compared to using a standard window. In winter, the optimized ventilation airflow rate is 102 m3/h. The energy-saving of utilizing a ventilated window with PCM energy storage is 26.6% compared to using a stand-alone ventilated window, and 32.8% compared to using a standard window. Based on the optimized ventilation airflow rate, a demand control ventilation strategy, which personalizes the air supply and heat pump setting based on the demand of each room, is proposed and its energy-saving potential examined. The results show that the energy savings of using demand control compared to a constant ventilation airflow rate in the house is 14.7% in summer and 30.4% in winter.

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Reducing energy waste in centrifugal pump systems through the implementation of BEP optimized pressure and flow control

10.32469/10355/57757 ◽

2015 ◽

Author(s):

◽

Shane Corlman

Keyword(s):

Centrifugal Pump ◽

Energy Savings ◽

Control Valve ◽

Speed Control ◽

Variable Speed ◽

Centrifugal Pumps ◽

Efficiency Curve ◽

System Variable ◽

Applicable Range ◽

Drive And Control

There currently exists a gap in the technology surrounding centrifugal pumps. When looking at modern literature regarding the application of centrifugal pump systems, the existing methods for control are throttle and speed control. Herein is described a new method, one which uses both throttle and speed control simultaneously to allow for the ability to precisely regulate pressure and flow for an entire system. Variable speed pumping, when combined with a control valve allows for control techniques which have the goal of optimizing the efficiency of the pump instead of just controlling flowrate. Developing a variable speed characterization and finding the best efficiency curve of a pump gives all the necessary tools to create a "dual controller" to operate a pump in the region of greatest reliability, always. Experiments show that neither fixed speed operation nor variable speed operation without a control valve can accurately maintain operation at the best efficiency point of the pump. Therefore, a novel control system using both a variable speed pump and a control valve is proposed to replace individual throttle and speed control. The proposed system, when used with the best efficiency curve as the operational target, maintains the best efficiency point for any flow requirement within the applicable range of the pump. Additionally, experiments have shown that energy savings from the proposed control scheme can exceed 60% -- a savings which no fixed speed system can match. Dual control with a variable speed drive and control valve can reduce energy consumption and increase pump life and reliability when compared to throttle control or speed control alone by reducing the amount of time that the pump is operating away from its best efficiency point. Similarly, it provides the tools needed to produce any performance that an operator desires, whatever the application may be.

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Energy consumption optimization for AC drives position control

COMPEL The International Journal for Computation and Mathematics in Electrical and Electronic Engineering ◽

10.1108/compel-10-2019-0429 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Branislav Ftorek ◽

Milan Saga ◽

Pavol Orsansky ◽

Jan Vittek ◽

Peter Butko

Keyword(s):

Control System ◽

Energy Saving ◽

Energy Savings ◽

Position Control ◽

Control Strategies ◽

Content Type ◽

Ac Drives ◽

Energy Demands ◽

Wide Range ◽

Energy Consumption Optimization

Purpose The main purpose of this paper is to evaluate the two energy saving position control strategies for AC drives valid for a wide range of boundary conditions including an analysis of their energy expenses. Design/methodology/approach For energy demands analysis, the optimal energy control based on mechanical and electrical losses minimization is compared with the near-optimal one based on symmetrical trapezoidal speed profile. Both control strategies respect prescribed maneuver time and define acceleration profile for preplanned rest-to-rest maneuver. Findings Presented simulations confirm lower total energy expenditures of energy optimal control if compared with near-optimal one, but the differences are only small due to the fact that two energy saving strategies are compared. Research limitations/implications Developed overall control system consisting of energy saving profile generator, pre-compensator and position control system respecting principles of field-oriented control is capable to track precomputed state variables precisely. Practical implications Energy demands of both control strategies are verified and compared to simulations and preliminary experiments. The possibilities of energy savings were confirmed for both control strategies. Originality/value Experimental verification of designed control structure is sufficiently promising and confirmed assumed energy savings.

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Energy saving potential of occupancy sensors in intermittent-use space types.

10.26686/wgtn.17151134.v1 ◽

2021 ◽

Author(s):

◽

Georgia Alexander

Keyword(s):

Time Delay ◽

Energy Saving ◽

Energy Use ◽

Energy Savings ◽

Cost Savings ◽

Sensor Technology ◽

Building Industry ◽

User Survey ◽

User Perceptions ◽

Energy Saving Potential

<p>For decades, studies have been suggesting the idea of occupancy sensors in intermittent use spaces for energy savings. This work investigates the potential energy savings of occupancy sensors in hallways, stairwells, seminar rooms and lavatories of an education building. Lighting is one of the largest consumers of energy in the building industry and these space types are often fully illuminated for long periods of vacancy. Lighting is for the user, not the building. Discussions centre around light use habits, energy saving behaviours and sensor technology such as time delay and daylight sensors. The experiment uses wireless light sensors and PIR sensors to measure light energy use and occupant use of 20 intermittent use spaces. A user survey was planned to run alongside the experiment to investigate user perceptions of changes in lighting but was discontinued due to unresolved software issues. Results of the experiment encouraged the use of occupancy sensors in intermittent use spaces. Lavatories attained highest energy saving potential 54%, seminar rooms highest annual cost savings per fitting $15.47 and highest annual energy savings 482kWh and hallways calculated the quickest payback of 8.6 years. Hallways, stairwells, seminar rooms and lavatories all offer potential for energy savings, supporting the theoretical ideas and success of occupancy sensors in intermittent use spaces.</p>

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CASE STUDY OF ENERGY CONSERVATION IN INDUSTRY BY APPLICATION OF LEAN TOOLS

International Journal of Engineering Applied Sciences and Technology ◽

10.33564/ijeast.2021.v05i12.018 ◽

2021 ◽

Vol 5 (12) ◽

Author(s):

N.Sujith Prasanna ◽

Dr.J.Nagesh Kumar

Keyword(s):

Energy Conservation ◽

Energy Saving ◽

Energy Cost ◽

Energy Use ◽

Energy Savings ◽

Sustainable Manufacturing ◽

Integrated Approach ◽

Energy Saving Potential ◽

Lean Tools

Energy cost is significant in many of the manufacturing activities. The efficiency of energy use is quiet low as there are substantial visible and hidden losses. Visible losses can be easily identified and corrective action can be taken. However hidden and indirect losses form a sizeable portion of the losses. Identifying these losses is not easy and requires an integrated approach which includes thorough study of process, operations and their interactions with energy use. Industries across sectors have implemented lean management principles which target various wastes occurring in the plant. This paper discusses case studies which highlight the exploitation of lean tools as a means for unearthing hidden energy saving potential that often go unnoticed. In addition to the energy savings which results in improved profits and competitiveness, the approach also aids the industry to pursue a path of sustainable manufacturing.

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Energy Saving Potential from Shading Design for Residential House in Rural Area

MATEC Web of Conferences ◽

10.1051/matecconf/201816401007 ◽

2018 ◽

Vol 164 ◽

pp. 01007

Author(s):

Dany Perwita Sari ◽

Yun-shang Chiou

Keyword(s):

Energy Saving ◽

Rural Area ◽

Energy Savings ◽

Simulation Analysis ◽

Residential Buildings ◽

Substantial Impact ◽

Energy Saving Potential ◽

Key Factor ◽

Residential House ◽

Shading Devices

There are some architectural factors in the energy saving design of residential houses in Taiwan. In addition, in rural area, window glazing is a key factor to reducing electricity. For these purposes, a simulation model of exterior shading has been done in this study. Various types of shading devices have been analysed and compared in terms of energy savings. Simulation analysis by DesignBuilder reveals that shading devices has substantial impact to minimizing energy consumption. The results derived in this paper could provide useful suggestions for the shading design of residential buildings at rural area in Taiwan.

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Study on movable light-shelf system with location-awareness technology for lighting energy saving

Indoor and Built Environment ◽

10.1177/1420326x16659691 ◽

2016 ◽

Vol 26 (6) ◽

pp. 796-812 ◽

Cited By ~ 7

Author(s):

Heangwoo Lee ◽

Sang-hoon Gim ◽

Janghoo Seo ◽

Yongseong Kim

Keyword(s):

Energy Consumption ◽

Energy Saving ◽

Energy Savings ◽

Full Scale ◽

Location Awareness ◽

Energy Saving Potential ◽

Recent Increase ◽

Lighting Energy ◽

External Conditions ◽

Incoming Light

Various ongoing studies regard light-shelves as one solution to the recent increase in lighting energy consumption. However, in previous light-shelf systems, the direction of incoming light was determined by external conditions, thereby limiting the efficiency of lighting energy saving. The purpose of the present study was to develop a movable light-shelf system with location-awareness technology and verify its performance. In this study, a full-scale testbed was established in order to test the proposed movable light-shelf system with location awareness as well as to verify its energy saving potential. The results were analysed and compared with the performances of previous fixed (Case 1) and movable (Case 2) light-shelf systems without location-awareness technology. The obtained results were as follows. (1) The proposed light-shelf system can respond to external conditions and to the location of the occupant by means of the control axis of the light-shelf module angle through modulation between the control axis of the angle of the previous light-shelf and the reflector of the light-shelf. (2) The proposed light-shelf system provides 90.0% and 86.6%/91.0% energy savings in comparison to Case 1 and Case 2, respectively.

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Analysis of Electrical Energy Savings From Daylighting Through Skylights

Solar Energy ◽

10.1115/isec2005-76077 ◽

2005 ◽

Author(s):

Abdelkarim Nemri ◽

Moncef Krarti

Keyword(s):

Energy Use ◽

Energy Savings ◽

Simulation Analysis ◽

Control Strategies ◽

Electrical Energy ◽

Office Building ◽

Analysis Tool ◽

Energy Saving Potential ◽

Lighting Energy ◽

The Impact

This paper provides a simplified analysis tool to assess the energy saving potential of daylighting for commercial buildings through skylights. Specifically, the impact of daylighting is investigated for various fenestration opening sizes, glazing types, control strategies, and geographic locations. A top floor of a prototypical office building has been considered in the analysis. The results obtained for the office building can be applied to other types of buildings such as retails stores, schools, and warehouses. Based on the simulation analysis results, it was determined that skylight to floor ratio more than 0.3 does not affect significantly the lighting energy savings. An optimum value of skylight to floor area ratio was found to be 0.2 to minimize the annual total building energy use.

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Analysis for Energy Savings Potential and Economics of Combined Air-Conditioning System with Temperature and Humidity Decoupled Treatment

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.280.71 ◽

2011 ◽

Vol 280 ◽

pp. 71-75

Author(s):

Zhong Chao Zhao ◽

Dong Hui Zhang ◽

Yu Ping Chen

Keyword(s):

Energy Consumption ◽

Energy Saving ◽

Air Conditioning ◽

Energy Savings ◽

Operating Cost ◽

Air Conditioning System ◽

Operation Mechanism ◽

Energy Saving Potential ◽

Temperature And Humidity

In this paper, the operation mechanism of combined air-conditioning system with temperature and humidity decoupled treatment (CACSTHDT) was presented, and the energy saving potential and economics of CACSTHDT were primarily analyzed through compared with a traditional air-conditioning system. The results indicated that CACSTHDT could save up to 28.64% energy consumption in comparison with a traditional air-conditioning system. The operating cost in one summer only was 71.36% of that cost of traditional air-conditioning system.

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