USE OF PMV CONTROL TO IMPROVE ENERGY EFFICIENCY IN COMFORT COOLING APPLICATIONS

Traditionally HVAC systems are controlled based on the sensed air temperature. Human thermal comfort sensation is a result of a number of environmental factors and air temperature alone is not always an adequate parameter for controlling thermal comfort in a conditioned space. The Predicted Mean Vote (PMV) is a commonly used tool for assessing human comfort rating. It takes into consideration six key factors: metabolic rate, clothing level, air temperature, radiant temperature, air speed and humidity. A PMV based control HVAC system has the potential to provide improved thermal comfort inside a space and to reduce energy consumption by taking into consideration all major thermal comfort variables. Computational Fluid Dynamics (CFD) is used to investigate the combined effect of air temperature, radiant temperature and air velocity on thermal comfort inside a conditioned office space during a hot summer day. An assessment and comparison of two control strategies, PMV based and air temperature based on thermal comfort and energy consumption has been undertaken using a simplified CFD model of office spaces.