Performance Evaluation and Comparison of Different HVAC Systems for Indoor Temperature Control and Energy Savings

Abstract

HVAC systems are primarily designed to ensure the thermal comfort of building occupants. Traditionally, HVAC systems regulate the fixed temperature to maintain thermal comfort by constantly monitoring the interior air temperature. ASHRAE 55 is a standard that provides acceptable ranges of operational temperatures for air-conditioned buildings. The HVAC system's set-temperature may be adjusted based on the operational temperature, which is influenced by both indoor air temperature and mean radiant temperature, in order to provide neutral thermal comfort for occupants. This research examines the thermal comfort and energy consumption of two identical HVAC systems that are controlled based on interior air temperature and operating temperature, respectively. Two office rooms with identical architectural arrangements situated in Hong Kong were chosen for a case study. The HVAC systems were controlled according to interior air temperature and operational temperature simultaneously, following occupancy schedules. The study found that an HVAC system regulated by operational temperature provides improved thermal comfort at the expense of a modest increase in energy usage. The study's primary results are valuable for designing energy-efficient HVAC systems and improving comfort in indoor spaces.