Fan Speed Control Research Articles

An agent-based hardware-in-the-loop simulation framework for building controls

In general, a hardware-in-the-loop (HIL) building simulation has lower cost and fewer practical limitations (e.g., scheduling issues) than field tests in occupied buildings, while also overcoming limitations of simulations alone by capturing the full behavior of some physical systems, equipment, and components. However, the implementation of an HIL can be difficult due to the scarcity of appropriate tools. This paper presents an agent-based framework for HIL simulation. It can be used for investigation of controller performance via controller-in-the-loop simulations and also HIL for system synthesis. In the latter case, both controllers and major equipment participate in tests to ensure that dynamics of equipment operation are correctly captured in addition to controller performance. The HIL simulation framework presented allows such actual physical parts to be included in the framework while representing others for which behaviors are better known and modeled in simulation models. The mechanism implemented in the framework to synchronize simulations in software with real-time operation of physical equipment is described. As an example, use of the HIL simulation framework is illustrated through a brief study of speed control of the supply fan in the air handling unit of a variable-air-volume building heating, ventilating and air-conditioning system.

Laptop Cooling Pad Temperature Monitoring System

Cooling pads are commonly used to reduce temperature of laptop to avoid overheating problem. However, existing cooling pads are prone to various limitations: fixed voltage in the hardware component, inaccurate temperature readings and lacked of computer-based temperature monitoring functions. In this paper, a laptop cooling system with multivoltage fan speed controller using real-time processor temperature readings is proposed. A graphical user interface (GUI) and color coded LEDs are also implemented to provide visual inspection of the temperature values captured from the laptop. The temperature values are displayed in graph and tabular form. The performance of the proposed cooling pad with computer-based monitoring application is evaluated against two other types of existing cooling pad systems. The experiments have shown that the temperature values can be monitored clearly with the proposed GUI. More importantly, the proposed cooling pad system has the potential to achieve lower temperature faster than the rest of the existing cooling pad systems.

An optimized active disturbance rejection approach to fan control in server

As more and more massive data storage drives are used in super high density, the power used to cool the servers has become an increasingly large component of the total power consumption. Therefore, improving server cooling efficiency has become an essential requirement in data centers. However, because the thermal dynamics of the server system has characteristics such as nonlinearity, significant inter-loop coupling, and continuously fast-changing/unknown workload disturbances, these pose huge challenges to control engineers and data center architect engineers. To address the above concerns, this paper presents an active disturbance rejection control based decoupling control algorithm for flash storage systems and CPUs in a one-unit (1U) server to simultaneously improve fan power consumption efficiency and regulate the server components’ temperature to avoid downgraded performance caused by overheating. In the study, a benchmark system is established based on the Samsung Mission Peak (MP) server where the thermal characteristics and existing solutions are both systematically evaluated. Performance of the design concept is proven in both simulation and a hardware testbed. With the proposed control solution, experiment results show that the temperature overshoot is greatly eliminated, temperatures are more tightly controlled, and the drive throttling rate are greatly decreased. Furthermore, the proposed method is shown to be able to save up to 45% energy versus a PID controller, save about 77% energy versus dynamic fan speed control method, and save about 98% energy versus native fan speed control.

Impact of demand controlled ventilation on system performance and energy use

Demand-controlled-ventilation (DCV) refers to a ventilation system with controlled air flow rate based on indoor air quality. DCV operates at reduced air flow rates during most of the operation time. Therefore, less energy is required for fan operation, compared to a constant-air-volume (CAV) ventilation system.Typically, DCV has a two-layer control with variable-air-volume (VAV) valves, and a fan speed control to maintain a constant-static-pressure in the duct system based on a pressure set point.However, this nominal design based fan pressure setpoint is higher than required when all VAV-valves are closed to a certain extent. Therefore, advanced pressure-reset (PR) control - resetting the pressure set point - potentially reduces fan energy use even further.This paper assesses the impact of fan control on both fan energy use and ventilation performance in DCV system of a densely occupied office. Results of a simulation model and realistic measurement setup are compared. The PR control, using air flow rate and VAV-valve position measurements as feedback, causes significantly reduction on fan energy use. These reductions compared to conventional DCV and CAV respectively, are approximately 10% and 72% in case of high occupancy and 50% and 93% in case of low occupancy. Largely, DCV with PR control is strongly considered, especially when occupancy is often expected to deviate significantly from the nominal conditions. Moreover, both simulations and measurements show that there is a clear trade-off between air flow rate deficit and fan energy use, when the fan energy use is lower, the air flow rate deficit is higher and vice versa. Furthermore, the results show that VAV-valve accuracy, characteristics and its lower operational limit hamper the ventilation system in achieving the predicted performance as in the simulation.

Resolution of HEV Battery Cooling System Inlet Noise Issue by Optimizing Duct Design and Fan Speed Control Strategy

Resolution of HEV Battery Cooling System Inlet Noise Issue by Optimizing Duct Design and Fan Speed Control Strategy

Evaluation of thermo-energetic behavior for demand-oriented operating of machine tool cooling systems

In state of the art machine tools, structural thermal displacement is commonly reduced by cooling and tempering measures. The application of these measures frequently counteracts the original goal of energy efficiency. To design demand-oriented cooling systems, this paper presents a method to evaluate cooling measures and control parameters by means of a variance-based sensitivity analysis regarding the thermo-energetic efficiency. The evaluation is carried out by using the example of a machine bed made of high performance concrete. The integrated fluid-air cooling system with fan speed control and the bed structure are modelled by lumped elements. In addition to the PID-control of the cooling fluid temperature, the evaluation considers a two-position control of separately controllable cooling circuits and the influence of ambient temperature. The criteria to evaluate are temperature differences within the machine structure, the dissipated heat and their proportions to deployed electrical energy.

Design and Development of Fan Speed and Light Speed Control Systems with Android-Based Voice Commands

At this time controlling electrical equipment in the form of fans and lights are still mostly using conventional switches. By using an android voice command device with a bluetooth connection, controlling the equipment can be easier. Using a Bluetooth connection will reduce the use of cables and speed up the process of activating or deactivating electronic devices because they do not have to get close to reach the switch. With input in the form of voice commands is very easy in controlling electronic devices such as fans and lights. With the adjustment of the fan speed and brightness of the lights with voice commands can save electricity and more easily in its settings

Modular Web-Based Interactive Hybrid Laboratory Framework for Research and Education

Online laboratories are offering new experimental potential for research and education purposes. This paper investigates the design and implementation of a web-based hybrid laboratory framework for research and education. Based on the previous work of the Networked Control System Laboratory (NCSLab), a hybrid laboratory with a highly modular design providing plug-in free online experiments is discussed. The proposed modular design of the NCSLab is provided in four aspects as hardware, software, control algorithms, and deployment, which covers all of the phases that compose an online experimental platform. The experiments that are integrated into the NCSLab for research and education are also explored in detail. To verify the effectiveness of the proposed modular design, a virtual wiring fan speed control system and a physical wireless power transfer system are deployed as examples to illustrate the virtual and remote experiments, respectively. The modular hybrid laboratory has been applied to research and engineering education at Wuhan University, and the corresponding pedagogical evaluation verified the effectiveness of the NCSLab.

Temperature based fan speed control and observing utilizing arduino

For the most part in various climatic conditions individuals will attempting to control the speed of the roof Fan in their room by physically controlling the Fan controller. Yet, by doing this physically is somewhat repetitive undertaking and not exact. Switching Fan regulator more often through manual control may damage the regulator and sometimes leads to current shock. The above discussed problems can be avoided by implementing the speed control mechanism of the fan in automatic way. A sensor is placed in the room to sense the room temperature in degree centigrade. As indicated by distinguished temperature a control circuit will control the speed of the fan. On the off chance that the room temperature is all the more, at that point the speed of the fan will increment. In the event that the room temperature is less, at that point the speed of the fan will naturally diminishes by the control circuit. The innovation OR the circuits utilized as a part of this undertaking are temperature sensor like LM35, and an aurdino UNO.

Performance increase for an open-cathode PEM fuel cell with humidity and temperature control

Water and thermal management of an open-cathode proton electrolyte membrane (PEM) fuel cell is developed in this study. A bubble humidifier, which is one of the balance of plant (BOP) systems, is newly installed to control the humidity of the fuel cell. A multiple-input-multiple-output (MIMO) fuzzy controller is developed, and proven to be superior in controlling a strong non-linear dynamical fuel cell system in real-time. According to the fuzzy control stratagem, the two main control objectives are the axial fan speed control for regulating temperature and the solenoid valve on/off control of the bubble humidifier for humidity variation. First, the axial fan speed is controlled to keep the fuel cell temperature within the desired point. Second, the bubble humidifier is utilized to humidify the inlet hydrogen to manage the water content of a membrane. After simulating the electrochemical and thermal fuel cell models, the optimal operating conditions are determined. A fuzzy logic controller with five inputs and two outputs is constructed and utilized to regulate the temperature and relative humidity of an open cathode fuel cell in real time. Results show that the proposed fuzzy controller effectively increased the output power of PEM fuel cell.

Global robust regulation control for a class of cascade nonlinear systems subject to external disturbance

The global robust regulation problem is studied for a class of cascade nonlinear systems subject to the external disturbance. The considered system represents more general classes of nonlinear uncertain systems, for example, the much weaker integral input-to-state stable (iISS) cascaded subsystem, the unknown control coefficients, the unmeasured states appearing in the nonlinear uncertainties and the external disturbance additively in the input channel. Combined the ideas of the Nussbaum-type gain and the disturbance as a generalized state, a dynamic extended state observer (ESO) based on a Riccati differential equation is constructed to overcome these difficulties. It is shown that the global robust regulation problem is well addressed by the proposed method. In the simulation part, the fan speed control system is used as a practical example to demonstrate its efficacy.

Experimental Demonstration of Frequency Regulation by Commercial Buildings—Part II: Results and Performance Evaluation

This paper is the second part of a two-part series presenting the results from an experimental demonstration of frequency regulation in a commercial building test facility. In part I, we developed relevant building models and designed a hierarchical controller for reserve scheduling, building climate control, and frequency regulation. In part II, we introduce the communication architecture and experiment settings, and present extensive experimental results under frequency regulation. More specifically, we compute the day-ahead reserve capacity of the test facility under different assumptions and conditions. Furthermore, we demonstrate the ability of model predictive control to satisfy comfort constraints under frequency regulation, and show that fan speed control can track the fast-moving RegD signal of the Pennsylvania, Jersey, and Maryland power market very accurately. In addition, we discuss potential effects of frequency regulation on building operation (e.g., increase in energy consumption, oscillations in supply air temperature, and effect on chiller cycling), and provide suggestions for real-world implementation projects. Our results show that hierarchical control is appropriate for frequency regulation from commercial buildings.

Experimental Demonstration of Frequency Regulation by Commercial Buildings—Part I: Modeling and Hierarchical Control Design

This paper is the first part of a two-part series in which we present results from one of the first worldwide experimental demonstrations of frequency regulation in a commercial building test facility. We demonstrate that commercial buildings can track a frequency regulation signal with high accuracy and minimal occupant discomfort in a realistic environment. In addition, we show that buildings can determine the reserve capacity and baseline power a priori , and identify the optimal tradeoff between frequency regulation and energy efficiency. In part I, we introduce the test facility and develop relevant building models. Furthermore, we design a hierarchical controller for the heating, ventilation, and air conditioning system that consists of three levels: 1) a reserve scheduler; 2) a building climate controller; and 3) a fan speed controller for frequency regulation. We formulate the reserve scheduler as a robust optimization problem and introduce several approximations to reduce its complexity. The building climate controller is comprised of a robust model predictive controller and a Kalman filter. The frequency regulation controller consists of a feedback and a feedforward loop, provides fast responses, and is stable. Part I presents building model identification and controller tuning results. Specifically, we find out that with an appropriate formulation of the model identification problem, a two-state model is accurate enough for use in a reserve scheduler that runs day-ahead. In part II, we report results from the operation of the hierarchical controller under frequency regulation.

Design of a climbing robot platform with protection device

In this article, a new wall-climbing robot platform with protection devices for city inspection is developed. After an overall structural introduction, the main protection devices of the robot are described in detail, including the support frame, the Ethylene Vinyl Acetate (EVA) shell, and the airbag. The support frame plays the roles of chassis and protection framework, so integrative and lightweight design is required. The EVA shell covers the support frame, and it protects the robot from overturn falling down from the wall. The airbag is designed both for sealing and protection. The mechanical model of the airbag is established based on the engineering thermodynamics theory and is used for force analysis when robot falls down on the ground. In addition, two-level distributed control system is designed to achieve the control of fan speed, straight moving, differential steering, position servo, and video transmission. To verify the feasibility of the climbing robot, many experiments are conducted, that is, experiments of movement, load capacity, adaptability to the wall surfaces, endurance, camera, sensor, and antithrow. The results show that the actual working performance of the climbing robot is favorable, thus providing a train of thought and inspiration for the antithrow design of climbing robot.

Closed-loop optimization control on fan speed of air-cooled steam condenser units for energy saving and rapid load regulation

In order to save more energy and quicken the load change speed of air-cooled steam condenser units, the closed-loop optimized control on the fan speed is proposed and its realization is worth making intensive study. In this regard, the study presents the static and dynamic models of air-cooled steam condenser, and the characteristics of turbine power output affected by fan speed. Then, the structure of closed-loop control on fan speed is designed. Furthermore, two optimized methods on condenser pressure based on fan speed control are separately discussed: the optimum condenser pressure is solved by the genetic algorithm to save more energy, and the condenser pressure regulation is combined with traditional boiler-turbine coordinated control to accelerate the load response. Case study in our paper proves that the fan speed optimization can significantly improve the unit load-following capability, and furthermore unit coal consumption has been significantly reduced when the unit operating in a stable load condition.

Experimental feasibility study of a new load-based method of testing for light commercial unitary heating, ventilation, and air conditioning (ASHRAE RP-1608)

This article investigated the feasibility a new load-based method of test for assessing the comprehensive performance figure of merit of roof top units. The measurements, according to the new load-based approach, characterize the relative changes in the unit performance when it operates in the field as if the unit was installed in an actual building. Depending on the mode of operation and on the outdoor air dry-bulb temperature, the roof top unit efficiency was about 41% to 9% lower than the steady state efficiencies determined by using the ASHRAE 116 Standard if the operation mode of the roof top unit was with economizer closed to the fixed minimum outside air position and without any speed control. When both the economizer and speed control technologies were activated, the measured efficiency increased to 205% with respect to the steady state efficiency. The focus of the load-based test was to provide data that could be used to project energy use and change point linear inverse modeling following ASHRAE Guideline (2014) could be applied to the data to compare expected annual energy use for the baseline (i.e., roof top unit with minimum outside air) to the improved modes of operation with fan speed control and outside air economizer control.

Development of an Integrated Cooling System Controller for Hybrid Electric Vehicles

A hybrid electrical bus employs both a turbo diesel engine and an electric motor to drive the vehicle in different speed-torque scenarios. The cooling system for such a vehicle is particularly power costing because it needs to dissipate heat from not only the engine, but also the intercooler and the motor. An electronic control unit (ECU) has been designed with a single chip computer, temperature sensors, DC motor drive circuit, and optimized control algorithm to manage the speeds of several fans for efficient cooling using a nonlinear fan speed adjustment strategy. Experiments suggested that the continuous operating performance of the ECU is robust and capable of saving 15% of the total electricity comparing with ordinary fan speed control method.

Constant design air flow industrial ventilation systems with regenerative dust filters: Economic comparison of fan speed-controlled, air damper controlled and uncontrolled operation

Variable speed drives for fans in small and medium-size ventilation systems with a constant design air flow, including a regenerative filter for dust separation, are evaluated in this paper. In the past, variable speed drives were considered for systems with varying air flow. It was found that this is also an appropriate measure to reduce the operating costs of such systems. With the chosen approach the calculated payback period based on 24h operation is between 0.7 and 1.7 years, depending on the size of the system. For systems in a two-shift operation the payback periods are still in the range of 1.4–3.4 years. The profitability of the installation of fan speed-control based on 12,000 service hours is in the range of 80–150%. A new operation mode, in which the filter cleaning is triggered at a fixed pressure drop of the filter cake, would further reduce the payback period and improve profitability. Systems with automatic damper flow control are much less economical. However, for the assumed conditions such systems are still better than uncontrolled systems. The installation of speed-control for fans in ventilation systems with a constant design air flow is therefore highly recommended for an economical design.

Effects of work practices and upper body movements on the performance of a laboratory fume hood

A hood user's work practices and upper body movements can adversely affect the performance of a laboratory fume hood. To quantify the possible effects, hood performance was measured while simulating typical user activities scenarios. The tested variables were two sash opening heights, two hood clutter settings, two thermal loads, and three hand–arm–trunk motions, totaling 24 (2 × 2 × 2 × 3) different test conditions. Hood face velocity was maintained at 0.5 m/s for all tests, using a fan speed controller. For each test condition, the hood's performance was evaluated using the ASHRAE 110-1995 tracer gas test method. Duplicate measurements were made for each condition, so that a total of 48 tests were conducted, in random order. Three-way ANOVA was performed to find significant effects of work practices and upper body movements on breathing concentrations. The degree of sash opening was the most significant factor affecting hood performance, followed by hand–arm–trunk motions and thermal load. The effect of hood clutter was not statistically significant, but the interaction effect with other factors was. The highest breathing concentration value occurred during the test with the sash fully open, arms-down posture, thermal load present, and hood clutter present. These conditions created complex airflow patterns inside the hood that resulted in leakage into the breathing zone. Although the test conditions were limited, the results of this study suggest that good work practices in combination with good hood design and adequate face velocity can significantly reduce worker exposure. Reducing sash height while working in front of a laboratory fume hood is vital to reducing potential exposure to the air contaminant generated inside the hood.

English

English