Designing Intelligent MIMO Nonlinear Controller Based on Fuzzy Cognitive Map Method for Energy Reduction of the Buildings

Farinaz Behrooz,Norman Mariun,Rubiyah Yusof,Zool Hilmi Ismail,Uswah Khairuddin

doi:10.3390/en12142713

Abstract

Designing a suitable controller for air-conditioning systems to reduce energy consumption and simultaneously meet the requirements of the system is very challenging. Important factors such as stability and performance of the designed controllers should be investigated to ensure the effectiveness of these controllers. In this article, the stability and performance of the fuzzy cognitive map (FCM) controller are investigated. The FCM method is used to control the direct expansion air conditioning system (DX A/C). The FCM controller has the ability to do online learning, and can achieve fast convergence thanks to its simple mathematical computation. The stability analysis of the controller was conducted using both fuzzy bidirectional associative memories (FBAMs) and the Lyapunov function. The performances of the controller were tested based on its ability for reference tracking and disturbance rejection. On the basis of the stability analysis using FBAMS and Lyapunov functions, the system is globally stable. The controller is able to track the set point faithfully, maintaining the temperature and humidity at the desired value. In order to simulate the disturbances, heat and moisture load changed to measure the ability of the controller to reject the disturbance. The results showed that the proposed controller can track the set point and has a good ability for disturbance rejection, making it an effective controller to be employed in the DX A/C system and suitable for a nonlinear robust control system.

Highlights

Heating, ventilating, and air-conditioning (HVAC) systems are a major cause of energy consumption in the building automation systems (BAS)
Structure and its ability for designing the controller on the basis of the system requirements and what outcomes are expected from the system, not in what way it works, the fuzzy cognitive map (FCM) method could be an appropriate solution for HVAC and air conditioning (A/C) systems
A new intelligent FCM control system was designed on the direct expansion air-conditioning (DX A/C)

Summary

Introduction

Heating, ventilating, and air-conditioning (HVAC) systems are a major cause of energy consumption in the building automation systems (BAS). Because of the depletion of energy sources in the world and the worsening fuel crisis, the need for advanced, improved control systems designs aimed at less energy usage and better performance are becoming a significant challenge for control engineers [1]. Because of the critical influence of HVAC systems on energy and power consumption, it is imperative to be familiar with the operation as well as the structure of HVAC systems [2]. The use of different controllers on HVAC systems is considered as an important issue, with the aim of increasing the system performance, by reason of their high installation demand in buildings and their huge energy consumption. The direct expansion air-conditioning (DX A/C) system is considered as a subgroup of HVAC systems. The mentioned system has two types of units, window units and split units, which are frequently employed in small- to medium-sized buildings by reason of having a simple configuration, low cost maintenance, and higher energy efficiency [3,4]

Methods

Discussion

Conclusion