• Journal of the Korean Society for Railway
• /
• v.3 no.4
• /
• pp.177-184
• /
• 2000

In this paper, a HVAC controller which has a bilinear system is designed to control the air temperature in building room and a saving of energy on the HVAC system. For modeling of the HVAC bilinear system, AHU(Air Handling Unit) is modeled on the control of inside-outside air flow using three dampers in a duct. A heat exchanger and the single room are also modeled by the energy conservation law. Under the modeling of the HVAC bilinear system, the control's law of the bilinear HVAC system is derived by Lyapunov's non-linear theory and Deress's the linear feedback laws for bilinear system. In this paper it was proved that the controller of the HVAC bilinear system is able to control the air temperature with a disturbance in order to get a target of temperature in the building room by the computer simulation when the control inputs regulate the air flow rate and a capacity of the heat exchanger.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.9 no.2
• /
• pp.76-82
• /
• 2009

A Heating, Ventilating and Air Conditioning (HVAC) system is a nonlinear multi-input multi-output (MIMO) system. This system is very difficult to control the temperature and the humidity ratio of a thermal space because of complex nonlinear characteristics. This paper proposes an adaptive fuzzy output feedback control based on observer for the nonlinear HVAC system. The nonlinear HVAC system is linearized through dynamic extension. State observers are designed for estimating state variables of the HVAC system. Fuzzy systems are employed to approximate uncertain nonlinear functions of the HVAC system with unavailable state variables. The obtained controller compares with an adaptive feedback controller. Simulation is given to demonstrate the effectiveness of our proposed adaptive fuzzy method.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.1081-1082
• /
• 2008

This paper presents adaptive fuzzy control based on observer for nonlinear HVAC system whose states are not available. Fuzzy systems are employed to approximate the unknown nonlinear functions of the HVAC system and the state observer is designed for estimating the states of the HVAC system. An adaptive fuzzy controller is firstly constructed without the controller singularity problem. The obtained control system shows robustness and effectiveness compared with classical feedback controller. Simulation results are provided to illustrate the control performance.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1205-1210
• /
• 2004

The 4-20mA analog signal used in the various industrial fields to interface sensor in distributed process control has been replaced with relatively simple digital networks, called "fieldbus, and recently by Ethernet. Significant advances in Internet and computer technology have made it possible to develop an Internet based control, monitoring, and operation scheduling system for heating, ventilation and air-conditioning (HVAC) systems. The seamless integration of data networks with control networks allows access to any control point from anywhere. Field compatible field devices become so-called "smart" devices, capable of executing simple control, diagnostic and maintenance functions and providing bidirectional serial communication to higher level controller. The most important HVAC of BAS has received nationwide attention because of higher portion of more than 40% in building sector energy use and limited resources. This paper presents the Internet-based monitoring and control architecture and development of LonWorks control modules for AHU (air handling units) of HVAC in viewpoint of configuring BAS network. This article addresses issues in architecture section, electronics, embedded processors and software, and internet technologies.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.3 no.2
• /
• pp.31-37
• /
• 2007

The fuzzy control algorithm for HVAC system has been developed for minimizing energy consumption while maintaining the comfort of indoor thermal environment in terms of the environmental variables such as time varying indoor cooling load and outdoor temperatures. The optimal set-points of control parameters with fuzzy control are supply air temperature, chilled water temperature and condenser temperature. This study has been done by using TRNSYS program in order to analyze the HVAC system response. As a result, the fuzzy control algorithm with PID algorithm shows good energy performance in comparison with conventional one.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.1014-1019
• /
• 2009

The optimal control system for heat source and HVAC system has been developed for minimizing energy consumption while maintaining the comfort of indoor thermal environment in terms of the environmental variables such as time varying indoor load and outdoor temperatures. The optimal set-points of control parameters are supply air temperature and chilled or hot water temperatures. The optimal control study has been implemented for biosafety laboratory by using TRNSYS simulation program in order to investigate energy performance for heat source and HVAC system.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.4
• /
• pp.365-370
• /
• 2007

This paper studies an automation problem of a heating, a ventilating, and an air conditioning (HVAC) for the development of smart space. The HVAC system is described by the fuzzy system for the stability analysis and the controller design. The linear matrix inequalities (LMIs) conditions are derived for the stabilization problem of the closed-loop system under the analog control. Also, it is required to digitally redesign the pre-designed the analog HVAC control system in order to accomplish the remote control via web. It is shown the this digital redesign problem can be converted to the convex optimization problem with the LMI constraints. An example is provided to show the effectiveness of the proposed method.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.84-89
• /
• 2008

The biosafety laboratory HVAC control technology may be applied in order to protect contamination of the researcher, supervisor and to prevent diffusion of biological pollution. In this study, a biosafety level, general configuration of control system, differential pressure control, distributed control system and network structure were discussed. These systems able to increase laboratory safety and efficiency of HVAC system.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.14 no.4
• /
• pp.138-146
• /
• 2006

Recently, a technology based on the proportional integral (PI) control have grown rapidly owing to the needs for the robust capacity of the controllers from industrial building sectors. However, PI controller generally requires tuning of gains for optimal control when the outside weather condition changes. The present study presents the possibility of reinforcement learning (RL) control algorithm with PI controller adapted in the HVAC system. The optimal design criteria of RL controller was proposed in the environment chamber experiment and a theoretical analysis was also conducted using TRNSYS program.

• Journal of Institute of Control, Robotics and Systems
• /
• v.18 no.8
• /
• pp.750-757
• /
• 2012

This paper focuses on human adaptive HVAC system that can regulate the thermal comfort of the resident in intelligent buildings. The thermal comfort is represented in this paper by PMV (Predicted Mean Vote) as defined by ISO 7730. This PMV value indicates how hot or cold a resident feels by considering temperature, humidity, resident's metabolic rate, relative air velocity, and clothing insulation. In order to develop such a system, a location detection system based on ZigBee module was used along with temperature sensors, other environment sensors. The human adaptive HVAC system was evaluated experimentally on a test bed emulating a room.