Virtual Test Bed Research Articles

EnergyPlus and CHAMPS-Multizone co-simulation for energy and indoor air quality analysis

This paper presents a co-simulation method using EnergyPlus and CHAMPS-Multizone for combined energy efficiency and indoor air quality (IAQ) analysis. The energy simulation estimates the energy consumption of HVAC systems, lights, and electrical equipment. The Indoor Environmental Quality (IEQ) simulation predicts the indoor contaminate concentrations for IAQ, the zone air temperature and relative humidity for controlled zone conditions, the Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD) for thermal comfort, and the illumination for daylighting performance. The energy, thermal comfort, and daylighting simulation are performed by EnergyPlus while the CHAMPS-Multizone is used for the IAQ simulation. In each time step, the CHAMPS-Multizone simulates the pollutant balance, and the ventilation rate required to control the contaminant concentrations under pre-established threshold values. EnergyPlus uses the ventilation rate to simulate the heat, air, and moisture balance, and the energy and daylighting performance. The Building Controls Virtual Test Bed is used for the run-time data exchange. Simulation cases using a 3-zone building are used to validate and demonstrate the benefit of the method. The co-simulation model is developed and implemented in a Virtual Design Studio (VDS) software framework with graphical user interface for integrated building system design. The co-simulation method is found to be especially useful in analyzing the interaction between IAQ and energy efficiency measures.

Comfort-based fuzzy control optimization for energy conservation in HVAC systems

The work presented herein illustrates the use of computational intelligence and optimization approaches for improving the fuzzy controller׳s performance in architectural heating, ventilation, and air conditioning system (HVAC). The primary purpose of the performed research is to find a method to moderate the energy use without compromising the comforts of the inhabitants. The control design used to meet this purpose includes the predicted mean vote (PMV) and predicted percentage dissatisfied (PPD) indices. The software of choice for evaluating PMV and PPD is EnergyPlus. Whereas, for the fuzzy controller and the evolutionary optimization framework, the co-simulation tool with building controls virtual test bed (BCVTB) is used in conjunction with Simulink. The ensuing comparison between EnergyPlus׳s thermal control of HVAC and our fuzzy approach is the outcome of the present research.

The FEDERICA infrastructure and experience

The European Commission co-funded project FEDERICA started in 2008 with the objective to support Future Internet research and experimentation. The project created a Europe-wide infrastructure based on virtualization in wired networks and computing elements, offering fully configurable and controllable virtual testbeds as a service to researchers. This article reviews the architecture, its deployment and current active status, usage experience, including virtual resource reproducibility and elaborates on challenges for Future Internet testbed support facilities.

Dynamic Demand Response Controller Based on Real-Time Retail Price for Residential Buildings

Demand response and dynamic retail pricing of electricity are key factors in a smart grid to reduce peak loads and to increase the efficiency of the power grid. Air-conditioning and heating loads in residential buildings are major contributors to total electricity consumption. In hot climates, such as Austin, Texas, the electricity cooling load of buildings results in critical peak load during the on-peak period. Demand response (DR) is valuable to reduce both electricity loads and energy costs for end users in a residential building. This paper focuses on developing a control strategy for the HVACs to respond to real-time prices for peak load reduction. A proposed dynamic demand response controller (DDRC) changes the set-point temperature to control HVAC loads depending on electricity retail price published each 15 minutes and partially shifts some of this load away from the peak. The advantages of the proposed control strategy are that DDRC has a detailed scheduling function and compares the real-time retail price of electricity with a threshold price that customers set by their preference in order to control HVAC loads considering energy cost. In addition, a detailed single family house model is developed using OpenStudio and Energyplus considering the geometry of a residential building and geographical environment. This HVAC modeling provides simulation of a house. Comfort level is, moreover, reflected into the DDRC to minimize discomfort when DDRC changes the set-point temperature. Our proposed DDRC is implemented in MATLAB/SIMULINK and connected to the EnergyPlus model via building controls virtual test bed (BCVTB). The real-time retail price is based on the real-time wholesale price in the ERCOT market in Texas. The study shows that DDRC applied in residential HVAC systems could significantly reduce peak loads and electricity bills with a modest variation in thermal comfort.

Experience From Hardware-in-the-Loop Testing of Drilling Control Systems

Summary Modern drilling ships and rigs are equipped with advanced computer systems for dynamic positioning, power generation and distribution, and drilling operations. It is well-known that software errors may lead to delays and nonproductive time and may compromise safety. Although the testing and verification regime for structures and machinery systems is well-established, most of the computer systems on today's drilling vessels are put into operation without independent testing and verification. Hardware-in-the-loop (HIL) testing is a test methodology used in several other industries. It facilitates the systematic testing of control-system design philosophy, functionality, performance, and failure-handling capability, in both normal and off-design operating conditions, and is conducted in a virtual test bed in which there is no risk to personnel, vessel, or equipment. Automatic drilling systems that rely on software to function properly often consist of a combination of components delivered by several suppliers. This means that, to maintain safety and to achieve the desired operational performance, control-system software from several suppliers must also run and work together as an integrated system. Marine Cybernetics has finalized the testing of drill-floor control systems for seven rigs, involving nine different vendors. This paper presents experiences from these projects in terms of project execution, test timing, and vendor cooperation and participation. Examples of typical observations are also presented.

Investigating communication and step-size behaviour for co-simulation of hybrid physical systems

This paper discusses the method of cooperative simulation of discrete and continuous models with the Building Controls Virtual Test Bed, a software environment that allows coupling different simulation programs. In the course of a project aiming the energy optimization in cutting factories, models of machines of differing complexity and a building containing them have to be implemented to further simulate the thermal processes. Since all partial models require individual modelling approaches, solver time steps, solvers or even simulators, the method of co-simulation is considered. The partial models will be implemented with Modelica, MATLAB, Simulink and Simscape and accessed with the co-simulation tool BCVTB. The simulation results show that this method of co-simulation can be sufficient for the needs of describing thermal systems with large time constants but has to be found insufficient for simulations requiring high accuracy and variable step solvers in the overall simulation.

Architecture and Modeling for Virtual Test Bed

Study of Virtual Test Bed theory is the prerequisite for further research and application. Contributions to its technology and implementation come from many directions and from many projects. The purposes and significance of Virtual Test Bed are described. The goals are analyzed. The conceptual architecture with generic relationships as the primary rack of Virtual Test Bed is build based on the hierarchical relationship between the concepts in simulation field, and the framework is proposed which lays the foundation for simulation system development based on Virtual Test Bed.

하이브리드 열펌프 동적 모델링 및 시뮬레이션

A hybrid heat pump is under development with the goal of utilizing 120% of primary energy resources. A plate heat exchanger is added between the compressor and air-cooled condenser of an ordinary heat pump to heat water. For successful operation of the heat pump, it is necessary to develop a control algorithm under various operating conditions. As a virtual test bed for that purpose, a dynamic model has been developed, to simulate its dynamic behavior. It was modeled in transient one-dimensions, with varying phase lengths considered. The model was implemented in Matlab and Simulink. Simulation results were effectively applied to design a control algorithm. They also provided physical insight into how to design and operate the system.

Development of a program complex for solving inverse problems of chemical kinetics and its implementation in a virtual test bed

Development of a program complex for solving inverse problems of chemical kinetics and its implementation in a virtual test bed

기상 예보 데이터와 일사 예측 모델식을 활용한 실시간 에너지 수요예측

This study was designed to investigate a method for short-term, real-time energy demand prediction, to cope with changing loads for the effective operation and management of buildings. Through a case study, a novel methodology for real-time energy demand prediction with the use of weather forecasting data was suggested. To perform the input and output operations of weather data, and to calculate solar radiation and EnergyPlus, the BCVTB (Building Control Virtual Test Bed) was designed. Through the BCVTB, energy demand prediction for the next 24 hours was carried out, based on 4 real-time weather data and 2 solar radiation calculations. The weather parameters used in a model equation to calculate solar radiation were sourced from the weather data of the KMA (Korea Meteorological Administration). Depending on the local weather forecast data, the results showed their corresponding predicted values. Thus, this methodology was successfully applicable to anywhere that local weather forecast data is available.

Generation and Rendering of Interactive Ground Vegetation for Real-Time Testing and Validation of Computer Vision Algorithms

In recent years, the realistic rendering of natural outdoor sceneries has become more and more important in many application areas. Regarding the development process of new algorithms for computer vision applications, testing and evaluation in real outdoor environments is time-consuming or hardly applicable in many cases. As a result,artificial testing environments are used, which differ from real-world environments, especially regarding realistically reacting ground vegetation. Thus, developers try to simulate natural environments in real-time virtual reality applications, which are commonly known as Virtual Testbeds. Since the first basic usage of Virtual Testbeds several years ago, the image quality of recent virtual environments has almost reached a level close to photorealism even in real-time due to new rendering approaches and increasing processing power of current graphics hardware. Thus, Virtual Testbeds can recently be applied in application areas like computer vision, that strongly rely on realistic scene representations. In this article, we introduce a novel ground vegetation rendering approach that is capable of generating large sceneries with realistic appearance and excellent performance. Our approach features wind animation, as well as object-to-grass interaction and delivers realistically appearing grass and shrubs at all distances and from all viewing angles. This greatly improves immersion, as well as acceptance, especially in virtual training applications. Nevertheless, the rendered results also fulfill important requirements for the computer vision aspect, like plausible geometry representation of the vegetation as well as its consistence during the entire simulation. Feature detection and matching algorithms are applied to our approach in localization scenarios of mobile robots in natural outdoor environments. We will show how the quality of feature matching results is influenced by violating the static scene constraint in the Virtual Testbed, as observed in highly unstructured, real-world outdoor scenes with wind and object-to-vegetation interaction.

A co-simulation method as an enabler for joint analysis and design of MAS-based electrical power protection and communication

Multi-agent system (MAS) protection is under investigation as a potential method for distributed control in modern electrical power systems. The coordination of the MAS is based on local measurements available to each agent’s site as well as on the information exchanged between agents over the communication network. Hence, the communication network should be considered to be a main factor in determining overall system performance. Numerical simulation is a fundamental tool of the design process. Existing electric power simulation tools can satisfactorily model traditional power systems where power and communication are considered to be decoupled and MAS are not present. Similarly, the simulation tools for communication systems have been developed independently from the application, particularly power system scenarios, so they are decoupled from the actual use of the information. If the loop between communication and power is closed and the coupling is strong, as in MAS-controlled power systems, such a simulation environment may yield unrealistic results. Aiming at filling this gap, this paper proposes a co-simulation solution for power systems, communication networks, and MAS, based on the extended capability of the co-simulation platform called VPNET. VPNET consists of three parts: Virtual Test Bed for time domain simulation of power systems, OPNET for the simulation of communication networks, and the Co-simulation Coordinator for data exchange and time synchronization between the other two simulators. The Co-simulation Coordinator has been exploited for MAS integration, as the rules of each agent are defined in the modules provided by the Co-simulation Coordinator. The proposed extended co-simulation platform is tested in the analysis of the performance of the MAS-based protection schemes of a medium-voltage DC shipboard power system. Numerical simulations have been performed for communication testing and protection testing. In the communication test, the network parameters (bandwidth and transmission time) are analyzed to evaluate the performance of the communication network under various conditions; in particular, links failure. The MAS-based protection system was then tested under various operating conditions of the communication network (latency and links failure). From the simulation results it can be seen that the designed MAS protection can handle these conditions successfully. Particularly in the link failure conditions, this co-simulation platform could simulate the re-routing process of the communication network and lead to correct protection performance, which is impossible with individual simulators alone. These simulation results show the utility of VPNET in exploring the design trade-offs between protection strategies and communication in the design phase.

Exploring the Possibilities of Co-Simulation with CATIA V6 Dynamic Behavior Modeling

This study shows how to utilize the CATIA V6 Dynamic Behavior Modeling (DBM) software environment for the purpose of co-simulation of physical models. The implementation of a co-simulation using Building Controls Virtual Test Bed (BCVTB) is demonstrated and the pros and cons are discussed. Further the methods for FMI export and import in CATIA are explored with respect to implementing a co-simulation either in CATIA itself or other host programs. The two approaches are displayed by implementing simple examples. Ultimately possible applications for an advanced tool to link 3D geometric data and systems simulation, with the potential to perform co-simulation, are presented.

Simulation-Based BEMS Control Through BCVTB and Its Application to a Ventilation System Under Operation

This paper aims to establish a simulation-based control system for better building performance with low energy cost during the operational stage. This integrated system utilizes BCVTB (Building Control Virtual Test Bed) as a middleware to connect a BEMS(Building Energy Management System) and simulation programs, including monitoring and measurement devices, an analysis model (EnergyPlus), and control algorithms. In addition, the co-simulation between EnergyPlus and Matlab/Simulink is conducted as well. The integrated system is applied to a mechanical ventilation system in a residential building. This simulation-based control approach shows energy saving potentials while maintaining good indoor air quality in the case study.

Model Based Design and Hardware in the Loop Testing in Power Electronics Courses

In this paper a low cost virtual test bed for educational purposes is developed and tested. Hardware-In-the-Loop (HIL) design concept as an experimental part of power electronics is considered. Software simulations lead to develop control of the studied system. Before a real-time implementation of the control, HIL simulations could be a very useful intermediary step. Thus a hardware device is introduced in the loop in order to take its real constraints into account. Used equipment is general purposes and can be utilized for controller implementation as well as virtual plant model. Simulations are performed under different conditions and results are presented graphically using virtual instruments on the designed front panels.

Feasibility study on a novel methodology for short-term real-time energy demand prediction using weather forecasting data

This study was designed to investigate a method for short-term, real-time energy demand prediction to cope with changing loads for the effective operation and management of buildings. Through a case study, a novel methodology for real-time energy demand prediction with the use of weather forecasting data was suggested. To perform the input and output operations of weather data, and to calculate solar radiation and EnergyPlus, a BCVTB (Building Control Virtual Test Bed) was designed. The BCVTB was used to predict daily energy demand, based on four kinds of real-time weather data and two kinds of solar radiation calculations. Weather parameters that were used in a model equation to calculate solar radiation were sourced from weather data of the KMA (Korea Meteorological Administration). After conducting energy demand prediction for four days, it was found that all inputted weather data have an effect on the prediction results. These data were applied to real buildings in order to examine their validity. The information data exchange between real-time weather data and simulation data was carried out fairly through the BCVTB.

Testing Technology of Tether Net System Based on Simulation

Performance testing and evaluation of system of systems has always been a challenge. In this paper, on the base of analyzing and concluding the traditional testing technology of tether net system, a method of tether net system testing based on simulation is posed. Discuss the conception, target, principle of system testing, the basic configuration and supporting technology of tether net system simulation environment are presented, and finally build virtual test bed environment , finish testing.

An open virtual testbed for industrial control system security research

Industrial control system security has been a topic of scrutiny and research for several years, and many security issues are well known. However, research efforts are impeded by a lack of an open virtual industrial control system testbed for security research. This paper describes a virtual testbed framework using Python to create discrete testbed components including virtual devices and process simulators. The virtual testbed is designed such that the testbeds are inter-operable with real industrial control system devices and such that the virtual testbeds can provide comparable industrial control system network behavior to a laboratory testbed. Two virtual testbeds modeled upon actual laboratory testbeds have been developed and have been shown to be inter-operable with real industrial control system equipment and vulnerable to attacks in the same manner as a real system. Additionally, these testbeds have been quantitatively shown to produce traffic close to laboratory systems.

A Research Framework for the Clean-Slate Design of Next-Generation Optical Access

A comprehensive research framework for a comparative analysis of candidate network architectures and protocols in the clean-slate design of next-generation optical access is proposed. The proposed research framework consists of a comparative analysis framework based on multivariate non-inferiority testing and a notion of equivalent circuit rate taking into account user-perceived performances and a virtual test bed providing a complete experimental platform for the comparative analysis. The capability of the research framework is demonstrated through numerical results from the study of the elasticity of hybrid time division multiplexing/wavelength division multiplexing–passive optical network based on tunable transceivers.

A framework for simulation-based real-time whole building performance assessment

Most commercial buildings do not perform as well in practice as intended by the design and their performances often deteriorate over time. Reasons include faulty construction, malfunctioning equipment, incorrectly configured control systems and inappropriate operating procedures. One approach to addressing this problems is to compare the predictions of an energy simulation model of the building to the measured performance and analyze significant differences to infer the presence and location of faults. This paper presents a framework that allows a comparison of building actual performance and expected performance in real time. The realization of the framework utilized the EnergyPlus, the Building Controls Virtual Test Bed (BCVTB) and the Energy Management and Control System (EMCS) was developed. An EnergyPlus model that represents expected performance of a building runs in real time and reports the predicted building performance at each time step. The BCVTB is used as the software platform to acquire relevant inputs from the EMCS through a BACnet interface and send them to the EnergyPlus and to a database for archiving. A proof-of-concept demonstration is also presented.