Academic literature on the topic 'Uninterruptible power supply unit cooling'

The problem of development and implementation of a simple and effective method of the rectifiers operation control for the modular uninterruptible DC power supply unit in order to increase its reliability is considered in this paper. The main idea of the method is to control the process of cyclic shifting of the switched-on power modules of the uninterruptible power supply by series switching into operation of each subsequent module from their unloaded reserve and switching out the previous one. The paper presents the control system structure where in addition to the central control module, it is proposed to add the control unit for power modules, which is responsible for implementing the process of their switching on and monitors their condition. In order to investigate the effectiveness of the proposed method, computer simulation model describing the power modules control logic is developed. The Simulink visual modeling environment and the mathematical tools of the Stateflow library component using state and transition diagrams are used in order to develop the simulation model. The developed simulation model is tested and the simulation results are given in the form of time diagrams of state change. The іmplementation of the developed method, due to the uniform reduction of the period during which the power modules of the uninterruptible power supply are on the switched-on loaded state, makes it possible to increase their operating time to failure, which in turn increases its reliability without deteriorating energy efficiency. The simulation results demonstrate the efficiency of the developed algorithm in various system operation modes. Based on the proposed method, hardware and software which is implemented as a part of intelligent computerized control system for uninterruptible DC power supply is created.

The article analyzes the operation of thyristor automatic switching devices for uninterruptible power supply units of nuclear power plants. They are part of the emergency power supply system for auxiliary electrical equipment with a rated voltage of 0.4 kV. In such a reliable power supply system for especially responsible consumers, alternative networks and backup sources are necessarily used. Typically, groups of consumers for auxiliary needs of nuclear power plants are powered from the inverter network, so that in the event of a shutdown of the backup bypass network, these loads continue to be powered by the uninterruptible power supply unit. It incorporates a charger – a controlled rectifier, a battery pack and a transistor inverter. The transition from one network to another in any direction must be “shockless” in order to avoid the operation of the protections of uninterruptible power units and other electrical protections of the reliable power supply system. If there are failures in the algorithms or their irrational organization, the processes of transition between networks may be accompanied by a violation of uninterrupted power supply or phase-to-phase short circuits. A structural simulation model has been created in the MatLab computer mathematics system for testing transition algorithms for various phase shifts of networks and transition directions. The algorithm of transition between networks for uninterruptible power units of one of the manufacturing companies that supplied equipment to nuclear power plants was analyzed. A safer optimal algorithm for controlling network switching with phase-by-phase control of the current drop in the disconnected network is proposed. The proposals are supported by the results of computer simulations.

Switch power module parallel operation system is one of the technological developing directions of power with high-power output and uninterruptible supply. The paper puts forward a concept to design switch power module parallel operation system, which adopts two TPS5430 chips to compose DC-DC cell parallel and through their load sharing to control chip UCC39002 to implement DC-DC unit outputting equalized current. It succeeds in building experimental prototype.

Hotel Grand Elite Pekanbaru mendapat suplai daya listrik dari PLN sebesar 1250 kVA dan mempunyai tiga buah unit Generator-set (Genset) kapasitas 500 kVA sebagai back-up suplai daya listrik apabila terjadinya pemadaman listrik dari PLN. Namun demikian penggunaan genset tersebut tidak dapat melayani beban secara cepat dimana hal ini disebabkan adanya kerusakan pada rangkaian Automatic Transfer Switch (ATS). Untuk itu diperlukan rancangan sistem suplai daya tak terputus yang dapat menyuplai beban, khususnya beban emergency dengan menggunakan Uninterruptible Power Supply (UPS). Dari hasil penelitian diperoleh total beban emergency Hotel Grand Elite Pekanbaru sebesar 125,779 kVA terdiri dari beban lift 32,670 kVA dan beban Elite Fitnes Center 67,952 kVA sehingga diperlukan kapasitas UPS sebesar 150 kVA. Penambahan suplai daya UPS sangat cocok karena disamping sebagai solusi akibat kurangnya daya listrik ketika terjadi pemadaman dari PLN dan juga dapat memback-up beban emergency pada Hotel Grand Elite Pekanbaru. Kata kunci : Generator-set, Uninterruptible Power Supply

The renewed interest for power generation using renewables due to global trends provides an opportunity to rethink the approach to address the old yet existing load shedding problem. In the literature, limited studies are available that address the load shedding problem using a hybrid renewable energy system. This paper aims to fill this gap by proposing a techno-economic optimisation of a hybrid renewable energy system to mitigate the effect of load shedding at the distribution level. The proposed system in this work is configured using a photovoltaic array, wind turbines, an energy storage unit (of batteries), and a diesel generator system. The proposed system is equipped with a rule-based energy management scheme to ensure efficient utilisation and scheduling of the sources. The sizes of the photovoltaic array, wind turbine unit, and the batteries are optimised via the grasshopper optimisation algorithm based on the multi-criterion decision that includes loss of power supply probability, levelised cost of electricity, and payback period. The results for the actual case study in Quetta, Pakistan, show that the optimum sizes of the photovoltaic array, wind turbines, and the batteries are 35.75 kW, 10 kW, and 28.8 kWh, respectively. The sizes are based on the minimum values of levelised cost of electricity (6.64 cents/kWh), loss of power supply probability (0.0092), and payback period (7.4 years). These results are compared with conventional methods (generators, uninterruptible power supply, and a combined system of generator and uninterruptible power supply system) commonly used to deal with the load shedding problem. The results show that the renewable based hybrid system is a reliable and cost-effective option to address grid intermittency problem.

Objectives. Due to the continuous rapid development of renewable energy sources, requirements for secondary power supply systems keep increasing from year to year. Productive uptime for end users is dependent on the efficiency and stability of the power supply system. Such systems should be able to distribute and store energy from renewable sources having various parameters and configurations. Therefore, the present work is aimed at developing technical solutions for efficient uninterruptible secondary power supply systems in low voltage DC networks.Methods. Advanced circuitry solutions are used for performing pulse conversions with high efficiency. The flexible hardware-software system is used for implementing the parameter control system.Results. An uninterruptible power supply for low-voltage DC networks is developed. The description of subsystems and calculations for all main elements including the power ones are given. Using a contemporary component base, the system prototype is assembled, configured, and measured by parameters. The presented solutions allow achieving the universality of the system in terms of the input and output voltage range. Support for the fast-charging Power Delivery protocol is integrated. As well as regulating the battery charging current and voltage, the Li+ battery charging controller permits changes in the number of chargeable cells. The monitoring and control unit monitors network parameters and controls the system automation. Using a microcontroller as the control device, it is possible to easily change control parameters by changing software settings. Dual redundancy of the module monitoring the built-in battery parameters is used to ensure the reliability and safety of system functioning. Support for the standardized I2C communication protocol with a separate power bus allows any necessary sensors to be connected for monitoring system parameters. External high-power devices controlled by a PWM signal may be added, if required. In the paper, the Li+ battery charging profile recommended by the manufacturer is provided.Conclusions. The designed system provides stable power supply to end users at a power consumption up to 40 W for at least 45 min. The automation demonstrates reliable operation.

AbstractAt 5:30 pm on December 17, 2010, shortly after a power failure, smoke filled the Intensive Care Unit (ICU) of Federico II University Hospital in Naples, Italy, triggering the hospital emergency alarm system. Immediately, staff began emergency procedures and alerted rescue teams. All patients were transferred without harm. The smoke caused pharyngeal and conjunctival irritation in some staff members. After a brief investigation, firefighters discovered the cause of the fire was a failure of the Uninterruptible Power Supply (UPS).RispoliF, IannuzziM, De RobertisE, PiazzaO, ServilloG, TufanoR. Warning! Fire in the ICU. Prehosp Disaster Med. 2014;29(3):1-2.

Finite-set model predictive controls have been widely used in inverter control because of the flexible target control and no need of a modulation unit. However, the mismatching of prediction model parameters produces prediction errors, resulting in a significant decline in the performance of finite-set model predictive controls. Aiming at the problem of model parameter mismatch, an extended-state observer was proposed to accurately estimate the disturbance of the system in this paper, and the obtained disturbance value was added to a finite-set model predictive control controller to compensate for the prediction error and achieve parameter robustness. By constructing a prediction model of the inverter output voltage in αβ coordinates, all the possible output voltage values were predicted by using different voltage vectors and system measurement values. A set of voltage vectors that minimized the cost function was selected, and its corresponding switching state was applied to the inverter in the next sampling period to achieve control of the output voltage quality. Both the simulation and experimental results showed that the finite-set model predictive voltage control method based on the extended-state observer can estimate the total disturbance quickly and accurately, suppress the influence of capacitance parameter disturbance, and improve the control effect of an inverter.

Les centres de données consomment de grandes quantités d'énergie électrique pour alimenter leurs équipements informatiques, leurs systèmes de refroidissement et leur infrastructure. Cette forte consommation d'énergie contribue à la demande globale sur le réseau électrique et à l'émission de gaz à effet de serre. En optimisant les performances énergétiques, les centres de données peuvent réduire leurs factures d'électricité, leurs coûts d'exploitation globaux et leur impact sur l'environnement. L'adoption de nouvelles solutions de refroidissement, telles que le refroidissement par liquide et le refroidissement indirect par évaporation, offre une plus grande efficacité énergétique et peut réduire de manière significative la consommation d'énergie liée au refroidissement dans les centres de données.Dans ce travail, deux études expérimentales ont été menées sur de nouvelles topologies de refroidissement pour les baies informatiques. Dans la première topologie, le système de refroidissement des baies est basé sur une combinaison de refroidissement à couplage étroit et de refroidissement direct des puces. Cinq racks avec des serveurs opérationnels ont été testés. Deux différences de température (15 K et 20 K) ont été validées pour tous les racks informatiques. L'impact de ces profils de différence de température sur les performances du centre de données a été analysé en utilisant trois systèmes de rejet de chaleur dans quatre conditions climatiques pour un centre de données de 600 kW. L'impact du profil de température de l'eau sur l'efficacité de l'utilisation partielle de l'énergie et de l'eau du centre de données a été analysé pour optimiser le système de refroidissement indirect équipé d'un système de refroidissement par évaporation à travers deux approches : la différence de température des baies et l'augmentation de la température d'entrée de l'eau dans le centre de données. Dans la seconde topologie, une étude expérimentale menée sur une nouvelle technique de refroidissement liquide d'immersion monophasé a été développée. Le dispositif expérimental a testé l'impact de trois fluides diélectriques, l'effet de la configuration du circuit d'eau et la puissance/le profil du serveur. Les résultats suggèrent que la demande de refroidissement du système dépend de la viscosité du fluide. Lorsque la viscosité passe de 4,6 à 9,8 mPa.s, la performance de refroidissement diminue d'environ 6 %. En outre, tous les profils de serveurs informatiques ont été validés à différentes températures d'entrée d'eau jusqu'à 45°C et à différents débits. La performance énergétique de cette technique et de la technique précédente a été comparée. Cette technique a permis de réduire la consommation d'électricité en courant continu d'au moins 20,7 % par rapport au système de refroidissement par liquide. Les performances de refroidissement des systèmes à refroidissement par air et par liquide et de la solution proposée ont été comparées au niveau du serveur. En utilisant la solution proposée, l'énergie consommée par serveur a été réduite d'au moins 20 % par rapport au système de refroidissement par air et de 7 % par rapport au système de refroidissement par liquide.En outre, une nouvelle technologie de refroidissement par liquide a été mise au point pour les unités UPS de 600 kW. Cinq essais thermo hydrauliques ont été réalisés dans différentes conditions thermiques. Un profil de différence de température de 20 K a été validé avec un fonctionnement sûr pour tous les équipements électroniques de l'onduleur, résultant en une efficacité thermique de 82,27 %. L'impact de la diminution du débit d'eau et de l'augmentation des températures de l'eau et de l'air dans la pièce a également été analysé. Une diminution des températures d'entrée de l'eau et de l'air de 41°C à 32°C et de 47°C à 40°C respectivement augmente l'efficacité thermique de 8,64 %
Data centers consume vast amounts of electrical energy to power their IT equipment, cooling systems, and supporting infrastructure. This high energy consumption contributes to the overall demand on the electrical grid and release of greenhouse gas emissions. By optimizing energy performance, data centers can reduce their electricity bills, overall operating costs and their environmental impact. This includes implementing energy-efficient technologies, improving cooling systems, and adopting efficient power management practices. Adopting new cooling solutions, such as liquid cooling and indirect evaporative cooling, offer higher energy efficiency and can significantly reduce the cooling-related energy consumption in data centres.In this work, two experimental investigations on a new cooling topologies for information technology racks are conducted. In the first topology, the rack-cooling system is based on a combination of close-coupled cooling and direct-to-chip cooling. Five racks with operational servers were tested. Two temperature difference (15 K and 20 K) was validated for all the IT racks. The impact of these temperature difference profiles on the data-centre performance was analysed using three heat rejection systems under four climatic conditions for a data centre of 600 kW. The impact of the water temperature profile on the partial power usage effectiveness and water usage effectiveness of data centre was analysed to optimise the indirect free cooling system equipped with an evaporative cooling system through two approaches: rack temperature difference and by increasing the water inlet temperature of the data centre. In the second topology, an experimental investigation conducted on a new single-phase immersion/liquid-cooling technique is developed. The experimental setup tested the impact of three dielectric fluids, the effect of the water circuit configuration, and the server power/profile. Results suggest that the system cooling demand depends on the fluid’s viscosity. As the viscosity increased from 4.6 to 9.8 mPa.s, the cooling performance decreased by approximately 6 %. Moreover, all the IT server profiles were validated at various water inlet temperatures up to 45°C and flow rates. The energy performance of this technique and the previous technique was compared. This technique showed a reduction in the DC electrical power consumption by at least 20.7 % compared to the liquid-cooling system. The cooling performance of the air- and liquid-cooled systems and the proposed solution was compared computationally at the server level. When using the proposed solution, the energy consumed per server was reduced by at least 20 % compared with the air-cooling system and 7 % compared with liquid-cooling system.In addition, a new liquid cooling technology for 600 kW Uninterruptible Power Supply (UPS) units. This cooling architecture gives more opportunities to use free cooling as a main and unique cooling system for optimal data centres (DCs). Five thermal hydraulic tests are conducted with different thermal conditions. A 20 K temperature difference profile was validated with a safe operation for all UPS electronic equipment resulting with a thermal efficiency of 82.27 %. The impact of decreasing water flow rate and increasing water and air room temperatures was also analysed. A decrease in inlet water and air temperatures from 41°C to 32°C and from 47°C to 40°C respectively increases the thermal efficiency by 8.64 %. Furthermore, an energy performance analysis comparison is made between air cooled and water cooled UPS units on both UPS and infrastructure levels

This master’s thesis deals with the basic design of diesel injection control unit hardware. There is a description of the whole blocks of Motorpal Common Rail diesel injection system in the introduction. Next are described requirement of control unit hardware. In the following are descriptions of parts, which was choosed for adjustment. The second part of thesis describes the whole design of control unit wiring diagram. There is described each block in detail in this part. Next part describes component placement on printed circuit board. The conclusion of thesis compare designed version of control unit with elderly versions.

碩士
國立中山大學
電機工程學系研究所
91
The thesis is one DSP-based On-Line UPS with USB2.0 communication interface and monitor software. The system is consisting of three sub-systems. The sub-system one is the DSP development system:First step, it uses the DSP to generate the PWM signal to inverter.Second step,ultilizes the ADC module of the DSP to implement the P type current controller in the inner feedback loop and P-I type voltage controller in the outer feedback loop.Third step,accomplishes the synchronous detection via ETU. And then transfer the UPS system parameters to USB2.0 development board through EMI.The sub-system two is the USB2.0 development system and the monitor software:The function of this sub-system is to transmit the parameters from DSP to PC in the specification of USB2.0.In order to achieve the goal, the firmware is required for the USB development board.Once the monitor software is activated, the firmware is downloaded to the board.The sub-system three is the electronic devices:like inverter、converter、pfc、power board、battery etc.Those devices constitute the fundamental hardware circuits modules of the UPS.

AbstractEnergy-efficient heating and cooling systems as well as intelligent systems for energy distribution are urgently required in order to be able to meet the ambitious goals of the European Union to reduce greenhouse gas emissions. The present article is intended to show that intelligent system extensions for the area of heating, cooling and electricity production for the industrial sector can lead to significant increase in efficiency. For this purpose, a simulation study for the expansion of a combined heat and power (CHP) plant with 2 MW thermal output using a 1.4 MW absorption chiller has been carried out. This shows that a heat-controlled CHP unit can significantly increase its running time. A system model was created for the initial situation and validated with existing measurement data. In the second step, this model was expanded to include the ACM module. The simulation was able to prove that in the event of a system expansion, the run time of the CHP unit can be increased by 35%. In addition to then increase of energy efficiency in the supply system, the analysis also focuses on the efficiency of the energy distribution via thermal networks in an industrial environment. The presented paper therefore also highlights the optimization potentials in the operation of thermal supply networks for industrial applications. For this purpose, a mathematical model has been developed which in addition to the components of the thermal network itself also comprises the producers and consumers. The specific construction of thermal networks for the supply of industrial properties requires adapted solutions for the simulation of such systems. Therefore, amongst other things, in the paper, solutions are shown for the modelling of direct flow local heating networks as well as for the operation of a cascade-controlled pump group.

Hydrogen systems for home heating are now very expensive. Partly due to the fact that they are designed to heat large rooms on average 200-500 m2 and consume a fairly large amount of energy on average 100-300 watt-hours, which is a very large figure. But for heating an average room where one person lives, one does not need to consume so much energy, the rooms in which a person is located rarely exceed 20 m2 in area. To heat such a room, the installation that I am developing will require approximately 3 watt-hours, such indicators can be achieved by using a special catalyst in my installation, the installation of processing ordinary water into distilled water will also reduce costs, which will make the installation autonomous at home. To operate this unit, only an electrical connection is required, and it is possible to periodically connect a plant for processing water into distilled water. Of the pluses, of course, I would like to note the absence of any emissions other than ordinary water, which makes this and any other hydrogen heating system completely environmentally friendly. And in total with low energy consumption, the system looks like a profitable analogue against the background of other heating systems. Also, if the system becomes more popular, it will be possible to build a production line and, having established production, reduce the price of the installation in order to make it even more affordable on the market.

For the accurate simulation about the heat transfer between the flowing oil coolant and ball screw structure, a heat-fluid-solid interaction transient FE (finite element) modeling method of precision ball screw unit is presented in this paper. This FE modeling method allows a supply power prediction of the oil coolant for precision ball screw unit. Then based on predictions, influencing tendencies from oil cooling strategy (oil supply temperature and volume flow rate) onto the time-varying supply powers of oil coolant are investigated. The research results demonstrate that: Firstly, the supply power of oil coolant has the increasing tendency with the time increase. Besides, the steady scale of oil supply power is in proportion to the oil supply volume flow rate, and in inverse proportion to the oil supply temperature. Finally, the maximum steady supply cooling power brings the guidance for the capacity selection of recirculation cooler for the precision ball screw unit.

A high efficient co-generation system named “Neighboring Communities Co-generation System” is proposed to a multiple dwelling house. The key technology of this system is to connect home and home with one loop of heat transfer line of one-inch diameter, and to level the heat demand by a heat storage unit in each house. This system requires a compact heat storage unit of quick response. In this study, a plate fin type brazing heat exchanger was built and tested as the heat storage unit. Sodium acetate trihydrate with a melting point of about 58 °C and a paraffin wax with a higher value of 74.8 °C were used as the phase change material (PCM). As a result, it was shown that the heat transfer in the heat storage unit was dominated by thermal conductivity in PCM. The paraffin wax showed higher responsibility and higher heat output due to its higher melting point and quite lower super cooling in solidification.

Most air handling units (AHUs) in commercial buildings have an air economizer cycle for free cooling under certain outside air conditions. During the economizer cycle, the outside air and return air dampers are modulated to seek supply air temperature at its setpoint. The supply air temperature is typically set at 13 °C (55 °F) to control humidity in the space. However, dehumidification is not necessary when the outside air is dry. Meanwhile, the space may have less cooling load due to envelope heat loss and/or occupant schedule changes. These facts provide an opportunity to use higher supply air temperature to reduce or eliminate mechanical cooling and terminal box reheat. On the other hand, a higher supply air temperature requires increased air flow as well as fan power. Therefore, an optimization question was formed, through which an optimal supply air temperature is identified to minimize total energy consumption. In our previous studies, through simulation, 90% of energy savings were concluded and a universal control sequence was also proposed for implementing the optimal control strategy. In this paper, experiments were conducted to validate the previously documented theory concerning the optimal supply air temperature reset. The previously recommended universal control sequence is implemented into the building automation system for an air-handling unit control to make the program ready for the next step of verifying energy savings previously simulated. This paper presents optimization control system setup and experimental results showing the program tuning procedures, through which the program is ready for the next step.

Abstract As a clean energy source, Low Temperature Reactor can be used for heating, desalination, industrial steam production, summer cooling, etc. It still has good application prospects at present. The reactor protection system is one of the important safety systems in Low Temperature Reactor, thus improving the reliability of the protection system can enhance the safety level and economic benefits of the reactors. The reliability of the protection system is directly related to its system structure, the quality of its components, and the power supply topology. The effect of the third factor is analyzed in this article. In the aspect of system reliability analysis, the RBD method is widely used and has many public research results. Based on the block diagram of protection system, this article establishes the RBD that considers the operation failure. According to the foregoing RBD, the protection system reliability is calculated, the minimum cut sets that can cause the protection system failure are analyzed, the different importance measures of each device in the protection system is determined, and the occurrence probability of the minimum cut sets and the importance measures are sorted as a basis for subsequent optimization of power supply topology. The Low Temperature Reactor protection system in this article is mainly composed of transducer, set-point comparison unit, logic coincidence unit, and safety trigger unit. The power supply of these units have many possible topological structures, which have different complexity and different reliability levels. Three improvement approaches are proposed for the power supply topological structure of transducer, set-point comparison unit and logic coincidence unit, the reliability of the optimized protection system is calculated and analyzed. The results show that by improving the power supply topology, the reliability of the protection system is improved without increasing the components’ quality and redundancy.

Abstract A typical northern nuclear power plant and a typical southern nuclear power plant are selected to optimize the cold end of the circulating water system with one machine and two pumps in an expanded unit system. And study the optimal operation mode of the circulating pump and the cold end configuration scheme with the minimum annual cost in this water supply mode. It is discussed how to combine the site conditions of the nuclear power plant, the price of raw materials and the main cold-end equipment of the steam turbine, the cost of the main structures of the water supply and drainage system and the related annual operating costs, power generation income and other factors, to seek the optimal solution through economic and technical comparison of multiple schemes. That is to select the optimal matching combination scheme of the configuration of the cooling water system such as the configuration scheme of the low-pressure cylinder of the steam turbine, the area of the condenser, the flow rate of the cooling water pump, and the cooling water pipe trench, and determine the economical and reasonable design parameters of the equipment at the cold end. By comparing the cold end optimization results of the constant speed scheme of 1 machine with 2 pumps, the frequency conversion scheme of 1 machine with 2 pumps and the expansion unit system scheme of 1 machine with 2 pumps, the frequency conversion scheme of 1 machine with 2 pumps is superior in terms of technology and economy and has a great advantage for the northern site. For the southern site, due to the higher water temperature and smaller variation, the advantage is less.

Combined heat and power (CHP), is an application that utilizes the exhaust heat generated from a gas turbine and converts it into a useful energy source for heating & cooling, or additional electric generation in combined cycle configurations. Compared to simple-cycle plants with no heat recovery, CHP plants emit fewer greenhouse gasses and other emissions, while generating significantly more useful energy per unit of fuel consumed. Clean plants are easier to permit, build and operate. Because of these advantages, Aeroderivative gas turbines will be a major part of global CHP growth, particularly in China. In order to improve energy efficiency and reduce CO2 emissions, China is working to build ∼1000 new plants of Natural Gas Distributed Energy System (NG-DES) in the next five years. These plants will replace conventional coal-fired plants with combined cooling, heating and power (CCHP) systems. China power segments require an extensive steam supply for cooling, heating and industrial process steam demands, as well as higher peak loads due to high population densities and manufacturing growth rates. GE Energy Aero recently entered the CCHP segment in China, and supported the promotion of codes and standards for NG-DES policy, and is developing optimized CCHP gas turbine packages to meet requirements. This paper reviews those policies and requirements, and presents technical case studies on CCHP applications. Appendix B highlights China’s draft “Guidance Opinions on Developing Natural-Gas Distributed Energy.”

Abstract Essential Service Water System (WES) is part of the nuclear power plant cooling system which provides the final heat sink for nuclear power plants. Therefore, WES must operate stably, safely and reliably for a long time. The total loss of WES accident is a design extended condition and will result in the loss of the final heat sink of the unit. The consequences of the accident are severe. In order to deal with the accident quickly and effectively and ensure the safety and economics of the power plant in accident condition, it’s necessary to formulate corresponding treatment strategy to deal with the transient. This paper developed a strategy for dealing with the total loss of WES with Residual Heat Removal System (RHR) not connected condition in Generation III nuclear power plant. The structure of the WES system and the types of failures that may occur are analyzed, and thus the symptoms of the faults are obtained and the entry conditions for the operating strategy are determined. The effect of faults on unit equipment and safety functions and the impact on nuclear steam supply system (NSSS) control are analyzed in this paper. Combined with the unit design, the system and equipment for controlling and mitigating related safety functions are analyzed, and the mitigation method and the fallback strategy of the fault are determined. Thereby a complete operating strategy of total loss of WES with RHR not connected is obtained. In addition, this paper analyzes and evaluates the operating strategy by simulating thermal hydraulic calculation for the first time. The results show that without staff intervention Component Cooling System (WCC) temperature reached 55°C limits after running a few minutes. Based on the intervention of the operating strategy proposed in this paper, WCC temperature reached the 55°C limits when the unit was operated at about 4 hours and 55 minutes. The result shows that and the strategy can effectively alleviate the failure and provide sufficient intervention time for the operator to bring the unit to a safe state.

Diffusion absorption refrigeration (DAR) cycles enable passive fully thermally-driven refrigeration for off-grid purposes. Typically, DAR units are designed for a given heat supply load and temperature, although real operation inevitably involves unsteady variations in these inputs. In this study, a thermally-driven DAR unit with a nominal cooling capacity of 120 W is connected to an electric heat source. The working fluid is ammonia-water NH3/H2O, with hydrogen (H2) added as an auxiliary gas to keep the system pressure constant and to decrease the partial pressure of the refrigerant (ammonia) in the evaporator. A control unit is used to adjust and measure the input heat-source power applied to the unit. The operating pressure of the system is 20.7 bar, the ambient temperature is 22 °C and the input thermal power is in the range 250 to 700 W. The cooling capacity of the unit and the input heat load are measured simultaneously at different operation conditions. To measure the cooling power, a cold box is constructed around the evaporator, and a second heater is located inside the cold box which sets the cold space temperature equal to that of the ambient. This allows the coefficient of performance (COP) to be evaluated. The COP and cooling capacity of the unit are investigated at part load by varying the heat supply, from which maximum values are obtained (0.28 and 110 W, respectively). Finally, experimental results are compared to the theoretical predictions from a thermodynamic model of a DAR cycle. Once validated, the model is also used to find the properties of the fluid mixture in different states in the DAR cycle.

Steam powered electrical generation, and nuclear generation in particular, requires significant water resources. Water resources throughout the world, and in many geographic areas in the United States, are challenged to meet environmental needs and the requirements of a steadily growing population including uses for the production of essential societal needs (food, hygiene, electricity). In Florida, ecosystem restoration is also recognized as a priority and places additional claims on a limited resource. Siting of a new nuclear generation facility in South Florida poses a considerable challenge, but also offers a unique opportunity. Florida Power & Light Company is proposing a new two unit AP-1000 project in southern Miami-Dade County that has included regional water issues in the conceptual design process. The project has selected reclaimed wastewater as its primary cooling water supply and, through specifically engineered mitigation projects, seeks to support regional ecosystem restoration projects. Disposition of power plant waste streams will be conducted by deep well injection, the first application of this established method for an operating nuclear facility. This paper identifies the design challenges presented by these regional issues and how they have been addressed by the engineering team.

With the rapid growth of data centers worldwide and the global shift towards energy sustainability, deploying new cooling technologies has an utmost importance. Conventional cooling systems such as chilled water system, usually have high capital costs and relatively low energy efficiency, leading to a high PUE and TCO values. Indirect evaporative cooling is a promising technology, which offers air cooling with high efficiency, hygiene air quality, and lower total cost. This paper details the design of a proof-of-concept data center with indirect evaporative cooling, which will be eventually deployed at megawatt-scale Baidu datacenters. BIN data analysis and CFD simulation are performed to optimize the physical design and operating conditions. CFD analysis of the data center room is established to optimize rack placement, air flow management, and cold aisle hot aisle configuration. A comprehensive TCO analysis is established, which shows a total savings of 9% using IDEC technology compared to chilled water system for cooling. In addition, TCO analysis indicates small to negligible effect of air supply temperature. Hence, air supply to the cold aisle is set to 27 °C to improve cooling performance. Finally, ROI sensitivity analysis is performed to measure the sensitivity of ROI on power usage effectiveness of the IDEC unit.