Experimental investigation on thermal inertia characterization of commercial buildings for demand response

Abstract

Characterizing the thermal inertia of commercial buildings is of great importance in quantifying demand flexibility, and experimental tests can be used for this purpose. However, existing studies tend to be qualitative and have a limited scope. In this study, a comprehensive experimental study has been performed to assess the thermal inertia of commercial buildings. In this field test, six buildings were selected with different sizes, vintages, and types of heating, ventilation, and air conditioning (HVAC) systems. The studied HVAC systems are used for comfort heating and cooling in over 80% of the U.S. commercial building stock. We quantified thermal inertia using building operation data collected under various thermostat excitation signals. We then studied the relationship between thermal inertia and intrinsic properties, such as floor area, HVAC system, etc., as well as operation condition indicators including outdoor air temperature, zone temperature, and occupancy. The test results indicate that the median values of the normalized charge response time and the normalized discharge response time of the five buildings are 1–5 hr/°C and − 5 to − 1 hr/°C, respectively. The results also show that the thermal inertia of commercial buildings may be sensitive to the HVAC system type but not the floor area or location of zones, i.e., core vs. perimeter. Furthermore, our results suggest that the relationships between the normalized charging/discharge response time and the zone/outdoor temperature may vary among zones and be highly nonlinear.