Performance of chillers under variable operating conditions and the effectiveness of energy recovery via enthalpy wheels for building applications.

The in-situ performance of the chillers and energy recovery via enthalpy wheels in air handling units in the HVAC system in the Baylor Research and Innovation Collaborative (BRIC) were evaluated. The data used in the evaluation were collected by the Siemens Building Automation System (BAS). Data were measured on the two identical 500-ton York chillers in the building for over twelve months and coefficient of performance (COP) was calculated. Each chiller operated over a range of chilled water and condenser water temperatures. Performance was modeled with the universal Gordon-Ng chiller model. Data were measured on the enthalpy wheels in four air handling units and was used to estimate sensible and total energy removed from the incoming air for an eight month period. For three of those months, additional data were collected to estimate the sensible and latent effectiveness of each enthalpy wheel which was used to estimate energy cost savings.