Cooling Water Pump Research Articles

Operational characteristics and performance optimizations of the organic Rankine cycle under different heat source/condensing environment conditions

The fluctuating heat sources and seasonal condensing environments are critical to the operation of Organic Rankine Cycle (ORC) under off-design conditions. This paper presents a comprehensive steady-state mathematical model developed using a newly built experimental platform. Focusing on the operational characteristics, including the evaporation pressure, condensation temperature, mass flow rate, and the performance of key equipment during the regulation of the expander, working fluid pump, and cooling water pump. Results show that the net efficiency initially increases before decreases, with both evaporation pressure and mass flow rate rising alongside the working fluid pump frequency. The quasi-two-stage single screw expander achieves an isentropic efficiency above 65 %. Additionally, flexible adjustments to the cooling water pump effectively regulate the cooling system, with timely cleaning of cooling pipelines enhancing net efficiency by up to 3.27 %. Optimization using the particle swarm algorithm improves system performance, achieving net efficiency enhancements of 1.8 % and 12.3 % under specific conditions. The novelty of this study lies in directly regulation of the expander, working fluid pump, and cooling water pump, significantly enhancing the off-design performance. This research provides valuable insights for researchers and designers, enabling flexible regulation of ORC operations to ensure efficient performance under varying conditions.

Construction of SuperKEKB vacuum control system and its eight years operation experience

SuperKEKB has two main rings (MRs), namely low- and high-energy rings, with circumferences of 3 km; beam transport (BT) lines; and a positron damping ring (PDR). We upgraded the MRs and BT line vacuum control systems and designed a new PDR vacuum control system for upgrading KEKB to SuperKEKB.Here, we describe the basic configuration of the vacuum control system, which includes the interlock logic (gate valve open/closed control, non-evaporable getter pump activation, and beam abortion). We subsequently present the collimator driving system and the cooling water control system for the beam pipe of the final focusing superconducting quadrupole magnet as examples of special SuperKEKB vacuum control systems. Examples of problems in the SuperKEKB vacuum control system, including the discharge at the high-voltage connector of the ion pump, stoppage of the cooling water pump for the vacuum system, and failure of the collimator position measurement device are described.

Energy Consumption Optimization for the Cold Source System of a Hospital in Shanghai - Part II: Operation Control Strategy Using EnergyPlus

Background: Energy consumption is a common problem in hospital buildings, which consume twice that of other public buildings. Therefore, it is of great significance to study the control strategy for the efficient operation of the cold source system. Objective: The study aimed to explore an efficient operation control strategy for cold source system, and new technologies and patents have emerged for the same. This work, utilizing EnergyPlus, modelled and analyzed the cold source system in a Shanghai hospital to optimize its operation. Methods: The accuracy of the simulation was verified by comparing it with experimental data. Based on the simulation results, the factors influencing the energy efficiency of the cold source system were analyzed, and then the operation control strategy of the cold source system was obtained. The XGBoost was used to fit the simulation results, and the operation strategy under full operating conditions was obtained. Results: The simulated results indicated the average energy saving rates during the summer season of the chillers, the chilled water pumps, the cooling water pumps, and the cooling towers to be 6.5%, -4.0%, 38.3%, and 5.4%, respectively, under the optimal operation control strategy. The average system Coefficient of Performance (COP) of the cold source system was 5.9, and the total energy consumption was 957016.3 kW·h, which was 7.1 % energy saving compared to that under the original operation. Conclusion: The conclusions of this study could provide references for the hospital buildings’ cold source system and group control method. This study has important practical significance for the efficient control strategy of cold source systems.

Study on Waste Heat Recovery of Fuel‐Cell Thermal Management System Based on Reinforcement Learning

Fuel cells are very sensitive to temperature. To enhance the temperature stability of fuel cells, in this article, a reinforcement learning control method is proposed to regulate the speed of the cooling water pump, and a waste heat recovery structure is designed based on this. First, the model's accuracy is validated by comparing it with experimental data. Subsequently, in the simulation results, it is shown that reinforcement learning control improves average temperature regulation capability by 5.6% compared to proportional‐integral‐derivative (PID) control. Following the incorporation of waste heat recovery, the energy consumption of the pump is reduced by 0.04 kWh in comparison to PID control. Similarly, for the air‐conditioning system, the energy consumption of the compressor is reduced by 0.63 kWh. For the same driving distance, hydrogen consumption decreases by 80 g. Additionally, the coefficient of performance increases by 1.5% in the waste heat recovery mode.

Integrating phase-change thermal storage into the indirect dry-cooling system of a thermal power unit and optimal operation strategy

Extreme conditions (high ambient temperature and crosswind speed) reduce the cooling efficiency of dry cooling towers, consequently impairing the thermal performance of thermal power units (TPUs). Phase-change material thermal storage equipment (PCMTSE) is integrated into an indirect dry-cooling system of the TPU to realize a partial cooling load of the cooling tower, thereby stabilizing and improving the thermal performance of the TPU. A model of the TPU and numerical model of the hybrid indirect dry-cooling system are established and coupled, with the inlet cooling water temperature of the condenser serving as the iterative criterion. Two integration schemes are proposed, one with the PCMTSE downstream (Scheme A) and the other with it upstream (Scheme B) of the dry cooling tower. The results show that Scheme A is recommended owing to its superior efficiency in terms of coal savings. The effects of the unit power load on the coal-savings efficiency of the PCMTSE during its charging and discharging processes have been revealed. Operating the PCMTSE at higher power loads aids in improving the thermal efficiency of the TPU during the PCMTSE charging and discharging processes. The charging process should be started at the “three high” working conditions: a high ambient temperature, crosswind speed, and unit power load. The working conditions that allow only one cooling water pump to operate should first be considered for the discharging process, and the “three high” working conditions should then be selected. The TPU equipped with the PCMTSE can save 11.42 tons and 12.74 tons of coal in two typical extreme daily conditions with the implementation of the proposed operating strategy.

Energy consumption during transient operation of coal-fired generating units with cold end system back pressure regulation

The dynamic characteristics of key parameters were investigated in this study, which reflected the operational flexibility and efficiency of thermal power units during load regulation. A refined model of the cold end of the unit was proposed. Simultaneously, an innovative exploration was conducted into the coordinated achievement of flexible load regulation and the promotion of energy-efficient operations. Two variables, the variable load rate and cooling water flow, were selected, and the continuous dynamic characteristics of unit energy consumption during load adjustment were determined. The ratio of total variable load coal consumption to load regulation and variable load time was defined as the average regulated coal consumption BZ, which was introduced to enhance the intuitive evaluation of flexibility and efficiency. It was shown that with the increase in variable load rate, there was a decrease observed in the total coal consumption during the variable load process. This trend was consistent with earlier publications. Concurrently, a reduction in cooling water flow had resulted in an increase in power generation coal consumption and a decrease in coal consumption for circulating cooling water pumps. The elevated rate of load variation was attributed to the increased flow of cooling water. A decrease of 14.9 % in back pressure was noted with the increase in the flow of the cooling water. As a result of this reduction in back pressure, the coal consumption rate for power generation was decreased by 1.334 g/kWh, reflecting a decrease of 0.43 %. Additionally, a reduction in total coal consumption of 0.16 t during variable load operation was witnessed, while a 1.97 % increase in the variable load rate was recorded. The optimal flexibility and coal-saving effect were achieved under the conditions of 30 MW/min and 60000 t/h, with ΔBZ = −50 g/(MW·s). Finally, the feasibility of the proposed scheme was verified through the case of a 350 MW unit.

Strategic Maintenance Boosts Global Power Plant Efficiency and Safety

This study addresses the maintenance of the Main Cooling Water Pump (MCWP) in Gas and Steam Power Plants, crucial for performance and sustainability. Existing practices often lack a comprehensive approach, integrating routine inspections with proactive maintenance strategies. We aimed to develop a maintenance framework that improves operational efficiency, safety, and environmental sustainability. Over a 12-month period, data from various facilities indicated that our holistic approach increased pump efficiency by 15%, reduced downtime by 20%, and enhanced compliance with safety and environmental standards. These findings underscore the importance of integrated maintenance practices in responding to evolving industry challenges and regulations. Highlights: Holistic maintenance approach vital for MCWP performance. Safety compliance crucial for personnel and asset protection. Maintenance enhances efficiency and sustainability efforts. Keywords: Maintenance, Main Cooling Water Pump, Energy Efficiency

Analyzing the risk of the ammonia storage facility using extended FMEA model based on probabilistic linguistic GLDS method with consensus reaching

Due to the energy crisis, ammonia stands out as an efficient hydrogen energy carrier. However, liquid ammonia's nature of toxicity, corrosiveness, volatility, flammability, etc., make its storage highly risky. It is essential to analyze the risk of the ammonia storage facility for its safety improvement. Failure mode and effect analysis (FMEA) has been a popular risk analysis method due to its ease of implementation. However, traditional FMEA is insufficient to model the uncertainty of risk assessment information, enhance the consensus among experts, aggregate experts' risk evaluation information, and derive reliable risk analysis results. To address these limitations, we introduce a hybrid probabilistic linguistic FMEA framework to analyze failure risk in the ammonia storage facility. First, the probabilistic linguistic terms (PLTs) are introduced to express uncertain risk evaluation information of failure modes. Second, a risk acceptability-based consensus-reaching process is introduced to measure experts' consensus on each failure mode's risk and improve their consensus. Then, a consensus degree-based ordered weighted averaging operator is introduced to fuse experts' risk evaluation information, where experts' weight is determined by their consensus degree. Furthermore, the gained and lost dominance score method is improved on the basis of the expected value of the PLTs to prioritize failure modes' risk. Finally, a case study of the risk analysis for the ammonia storage facility is performed to show the efficiency of the extended FMEA. The case study indicated that condenser cooling water pump failure and failure of level transfer are the top two failure modes and have risk scores of 0.126 and 0.091, respectively.

Study on Unsteady Flow Characteristics of Cooling Water Pump for Nuclear Power Plant Equipment under Low Flow Rate Conditions

During the operation of cooling water pumps, it is necessary to operate them under conditions of low flow rate. In order to improve the unstable performance of the cooling water pump under low flow rate conditions. Taking the cooling water pump as the research object, the internal flow and pressure pulsation characteristics of the cooling water pump under 0.4Q to 0.6Q conditions were investigated, and the influence of different operating conditions on the performance and vibration of the cooling water pump was analyzed. The ANSYS CFX 2022 software and the SST k-ω turbulence model were used to perform a three-dimensional numerical simulation of the cooling water pump. After analyzing the simulation results, the velocity and pressure cloud and streamline diagram within the semi-spiral suction casing and impeller were obtained. The internal flow state of the cooling water pump was then analyzed in detail under low flow rate conditions. At the same time, a series of monitoring points were set up within the impeller, and the pressure pulsation within the impeller was analyzed using the frequency domain diagram and the radial force polar coordinate diagram. The results show that at flow rates between 0.4Q and 0.6Q, a certain amount of vortex has been generated in the suction casing, which affects the flow state when entering the impeller. Furthermore, significant vortices have been generated in the middle and back part of the blade and mainly concentrated in the pump cover of the mid-open pump. At the same time, when in low flow rate conditions, the primary frequency of pressure pulsation is mainly the axial frequency, with three times the axial frequency and blade frequency following. The amplitude of the pressure surface (PS) of the blade is greater than that of the suction surface (SS) and increases as the flow rate decreases. The internal radial force corresponds with the result of pressure pulsation and exhibits a certain pattern. This study outlines the coolant pump’s internal flow and pressure pulsation characteristics under low-flow conditions. It proposes a solution to stabilize the cooling water pump at low flow rates and provides theoretical guidance for optimizing its design.

Research on energy consumption analysis of air conditioning and refrigeration equipment based on perceptron model

Abstract This paper mainly studies the energy consumption of air conditioning and refrigeration system from the perspective of the dynamic operation of air conditioning systems and selects the energy consumption of a chiller system, cooling tower system, chilled water pump system and fan coil system, which affect the energy consumption of air conditioning system, as model variables. An integrated learning method based on a multilayer perceptron is proposed to integrate spatial features with temporal features, and a spatio-temporal prediction model for air conditioning energy consumption analysis is established under the Seq2Seq framework, and then the input curves of the four variables with load change under the optimal operation of the air conditioning system under dynamic load are derived. The results show that the deviation between the simulated value and the measured, calculated value of the energy consumption analysis model of air conditioning and refrigeration equipment based on the multilayer perceptron is within 5%, which can effectively and accurately predict and reduce air conditioning energy consumption by 15% to 20%. The maximum energy-saving efficiency can reach 30% when the air conditioning system is in optimal operation under dynamic load, and the energy-saving effect of the chiller, chilled water pump and cooling water pump is relatively significant. The research results of this paper have a certain reference value for reducing the energy consumption of air conditioning systems in practice.

Control strategies of pumps in organic Rankine cycle under variable condensing conditions

The working medium pump and cooling water pump are important components in organic Rankine cycle system. However, they have not received as much attention as the expander and working medium. Simultaneously, the dramatic changes in condensing environment deviate the organic Rankine cycle working point from the designed operating conditions. Hence, this paper focused on the performance improvements and control strategies of working medium pump and cooling water pump in small-scale organic Rankine cycle under variable condensing conditions. A model was established to predict the performances of an organic Rankine cycle system with R245fa, especially the pumps in the system, under variable condensing conditions. The results showed that the overall efficiency of multi-stage centrifugal pump was between 14% and 39% at an estimated speed of approximately 1600 RPM to 2328 RPM. In winter conditions, the back work ratio increased from 0.05 to 0.19 with increasing evaporation pressure and decreasing mass flow rate. In other words, it is unnecessary to pursue excessively high evaporation temperature at low rotational speed of multi-stage centrifugal pump. As for the cooling water pump, it is feasible to reduce the power consumption of the cooling system through changing the rotational speed of water pump. The water pump can be operated with high efficiency (between approximately 58.4% and 65.3%, corresponding to an estimated speed range of 1374 RPM to 1813 RPM) when the system run in optimum operating conditions. It is also found that the performance of organic Rankine cycle was strongly influenced by fluctuating ambient temperature, with the net efficiency and net power increase of 3.36 % and 5.11 kW in winter compared to summer.

Comparative study on different energy-saving plans using water-side economizer to retrofit the computer room air conditioning system

An energy efficient, environmentally friendly and economical retrofit plan of traditional computer room air conditioning system is necessary to reduce energy consumption of data centers. In this study, two energy-saving retrofit plans, a computer room air handler system with water-side economizer (Plan 1) and a loop thermosyphon system with water-side economizer (Plan 2), are compared with an air-cooled computer room air conditioning system (existing cooling system) in a data center. To analyze and compare the energy efficiency, environmental and economic potential, energy models of the existing cooling system and retrofit plans are established. Under different set points (including supply chilled water temperature and supply air temperature) and 2.08–6 kW average electric power of racks, the free cooling periods of Plan 1 and Plan 2 reach 3878–5867 h and 4541–7661 h, respectively, which lead to the annual energy consumption of Plan 1 and Plan 2 decreases by 27.6–47.3% and 53.4–63.6%, respectively. Due to the lower annual energy consumption of main equipment (including chillers, chilled water pumps, cooling water pumps and terminal equipment), Power Usage Effectiveness of Plan 2 is 0.049–0.090 lower than that of Plan 1, and Global Coefficient of Performance of Plan 2 is 23.3–67.3% higher than that of Plan 1. Furthermore, the annual CO2 emissions of Plan 1 and Plan 2 are 337.3–557.1 tons and 599.8–1106.9 tons less than those of the existing cooling system at different operating stages respectively. Finally, the dynamic payback periods of Plan 1 and Plan 2 are 4.11–5.42 years and 1.64–3.57 years.

A novel method of variable flow operation in district cooling system: A case study

The district cooling system (DCS) is generally considered to be a key efficient cooling technology to cope with the increasing cooling demand. However, the energy consumption of pumps in DCS accounts for a large proportion. This work demonstrated a novel variable flow control strategy based on measured operating parameters. An existing DCS in a subtropical climate zone was used as the baseline model, denoted as Case A. Furthermore, using TRNSYS software, the variable flow control of the chilled water pumps and the cooling water pumps in Case A was performed in turn, and two variable flow models were established, denoted as Case B and Case C, respectively. The operation strategies capable of dealing with the diversified cooling loads were developed and simulated. The results indicated that compared with Case A, the newly proposed models Case B and Case C reduced the energy consumption by 9.50% and 14.15%, cut down CO2 emissions by 9.45% and 14.18%, saved costs by 10.34% and 15.16%, respectively. Moreover, the efficiency of the two models was also improved by 10.70% and 16.67%, respectively, compared with the Case A. Effective operation strategies can further improve the performance of DCS, thereby providing energy-saving and efficient cooling solutions.

Design and operation of high-power permanent magnet speed regulator used in industry

A high-power permanent magnet speed regulator is applied to a cooling water pump for conserving energy during the steel production in Magang (Group) Holding Co., Ltd. The designed setup of high-power permanent magnet speed regulator with a mobile base is shown in this manuscript, and the magnetic eddy under the different meshing area between driving and driven shafts has been simulated. And estimation indicates that the magnet speed regulator-controlled cooling water pump can save electric energy by 22%, about 1,756,400 kW·h per year, compared to the traditional valve-controlled pump, and the waste heat generated by this setup is below 5 ten-thousandths of the shaft power. Meanwhile, the permanent magnet speed regulator has a much lower vibration because of this non-contact way between the driving and driven shafts.

Stepwise Optimization Method of Group Control Strategy Applied to Chiller Room in Cooling Season

Central air-conditioning systems account for the largest share of energy consumption in public buildings, wherein the chiller room is the main source. The current empirical strategies of chiller room group control have difficulty realizing integrity, timeliness, and equipment adjustment accuracy and lead to energy wastage. Therefore, the operation strategy optimization model is of great value for achieving energy savings. This study proposed a stepwise optimization method for central air-conditioning systems, which is divided into the chilled side (the chiller and chilled water pump) and the cooling side (the chiller, cooling water pump, and cooling tower). The optimal points of the two sides are calculated sequentially and integrated as the global optimization result. To construct the stepwise optimization model, mathematical power models of the equipment in use were established to provide mathematical support for objective functions, and a short-term load prediction model with a matching optimization step size was established for energy constraints. The TRNSYS simulation model was developed to verify the energy-saving effects of the stepwise optimization model according to the energy-saving rates of 6.41% and 13.56% attained in both cases. The stepwise optimization strategy can more effectively guide practical applications and provide another way of thinking with respect to the group control optimization of chiller rooms in public buildings.

Numerical modelling of the cooling water system of a 106MW Hydro-Power Plant using EPANET

The present paper studies the behavior of the new proposed cooling water pumps for a 106 MW Hydro-Power Plant using EPANET. This case-study Hydropower Plant, located in the south of Romania and equipped with two Francis units 53 MW each, processing a 269m gross head, presently goes through a rehabilitation process. The cooling water system of this Hydro-Power Plant consists in four centrifugal pumps, two for each unit, and two additional pumps for the 130 MVA step-up transformer. The rehabilitation process involves the replacement of these pumps. A numerical model following the exact configuration of the cooling water system in what regards pipes diameters, lengths and roughness was designed in EPANET. The focus is to verify if the required pressure is ensured at the cooling water consumers of the plant considering their specific flow demand and if the velocity in the system pipes is within the acceptable limits during the power production process.

Gasification process of palm kernel shell to fuel gas: Pilot-scale experiment and life cycle analysis

This research demonstrates a palm kernel shell gasification system for producing fuel gas, also known as producer gas. Using air as an oxidant, the gasification process converts palm kernel shells into fuel gas which contains combustible gases, such as hydrogen, carbon monoxide, and methane with nitrogen dominating the composition of the gas. This fuel gas can supply heat via direct combustion or generate electricity for fossil fuel substitution of an internal combustion engine. As a biomass-derived gas, the fuel gas is characterized as carbon-neutral inherently. During the conversion process, the system needs electricity to power the screw feeder, air blowers, and cooling-water pumps, and to rotate the gasifier's bottom plate to take the char out. Based on the experiments, mass balance, and energy balance calculations, this study examines the global warming, acidification, and eutrophication potential using the openLCA v1.10.3 software and Environmental Footprint (MID-Point indicator) database for impacts assessment when the system is operated in Indonesia and Malaysia with various electricity sources. It is found that the feedstock contributed most of the global warming potential and eutrophication potential, while the electricity dominated the acidification potential. This study recommends operation at a lower equivalent ratio to reduce environmental impacts.

Deep Forest-Based DQN for Cooling Water System Energy Saving Control in HVAC

Currently, reinforcement learning (RL) has shown great potential in energy saving in HVAC systems. However, in most cases, RL takes a relatively long period to explore the environment before obtaining an excellent control policy, which may lead to an increase in cost. To reduce the unnecessary waste caused by RL methods in exploration, we extended the deep forest-based deep Q-network (DF-DQN) from the prediction problem to the control problem, optimizing the running frequency of the cooling water pump and cooling tower in the cooling water system. In DF-DQN, it uses the historical data or expert experience as a priori knowledge to train a deep forest (DF) classifier, and then combines the output of DQN to attain the control frequency, where DF can map the original action space of DQN to a smaller one, so DF-DQN converges faster and has a better energy-saving effect than DQN in the early stage. In order to verify the performance of DF-DQN, we constructed a cooling water system model based on historical data. The experimental results show that DF-DQN can realize energy savings from the first year, while DQN realized savings from the third year. DF-DQN’s energy-saving effect is much better than DQN in the early stage, and it also has a good performance in the latter stage. In 20 years, DF-DQN can improve the energy-saving effect by 11.035% on average every year, DQN can improve by 7.972%, and the model-based control method can improve by 13.755%. Compared with traditional RL methods, DF-DQN can avoid unnecessary waste caused by exploration in the early stage and has a good performance in general, which indicates that DF-DQN is more suitable for engineering practice.

중대형 선박 엔진용 냉각수 펌프 개발

The cooling pump for medium and large marine engines is a centrifugal pump, which circulates the coolant to cool the engine, lubricating oil and fresh water. As the built-in engine cooling water pump uses a large amount of power compared to other auxiliary equipment driven by the engine power of a ship, proper design of components, such as the impeller, is required to improve the pump efficiency to 60% or more, and without appearance of cavitation. In this study, the impeller, volute casing, and housing that correspond to various engine specifications of marine engine manufacturers, were used. The pump installed marine engines with a total efficiency of 60% or more were designed with CFturbo S/W. Performance tests of prototypes were conducted and the results were compared and reviewed. Ultimately, high efficiency and cavitation avoidance design technology of cooling water pump were acquired.

Digital twin-driven intelligent maintenance decision-making system and key-enabling technologies for nuclear power equipment

In the life cycle of nuclear power equipment (NPE), the long-term high-safety maintenance services play a vital role in ensuring their optimal operation. However, as the complex system equipment with high-safety requirements and high costs, there are lots of limitations of traditional time-based maintenance strategies for NPE. For example, the maintenance service process is invisible, the condition monitoring is mainly based on manual inspection, and the maintenance decision-making mainly depends on personal experience passively. Digital twins (DT) are an effective way to break the “information isolated island” in the whole life cycle, which can give full play to the value of data to realize the visualization of operation process of NPE. Nevertheless, nowadays, the application of DT in the field of nuclear industry is at the exploration stage, and there is lacking systematic and practical research. Thus, a novel DT-driven intelligent maintenance decision-making system involving three key-enabling technologies is proposed in this paper. Firstly, the DT-driven maintenance service mode is introduced, and its corresponding system framework is built. Then, the key enabling technologies such as DT modeling, condition monitoring and dynamic pre-alarm, and systematic intelligent maintenance decision-making and verification are expounded in detail. Finally, the cooling water pump is regarded as the case to verify the proposed method. The DT prototype system is developed and verified in the novel system, which demonstrates the novel system and the three key-enabling technologies are feasible and practical.