Lawrence Berkeley National Laboratory

In this paper we apply HVAC control modeling tools implemented in the OpenBuildingControl project. We utilize the Control Description Language, currently being standardized through ASHRAE Standard 231P, and our libraries of control sequences based on ASHRAE Guideline 36. We created a closed-loop model of a cooling plant that includes a chiller, a water-side economizer, and an evaporative cooling tower. The plant provides cooling at 27◦C zone supply air temperature to a data center in Sacramento, CA, USA. We present chiller plant energy use comparison using a base and an alternative (ASHRAE Guideline 36) set of control sequences. We compare annual and summer season power usage effectiveness and illustrate controller operation. The results show a 25% annual energy use reduction with the alternative controls. The capabilities of simulation-based control performance evaluation, enabled through our tools, will further support energy efficiency, grid flexibility, and resilience aspects of system controls.