RP-321 -- HVAC Systems Dynamics and Energy Use in an Existing Building ✓ Most Recent

The overall objective of the project was to determine operating strategies for HVAC systems which incorporate system dynamics and interactions and which will potentially reduce energy use. In keeping with the overall objective of the project the following specific goals were established:

1) To study the process dynamics and interactions of a building HVAC system through the use of collected test data and equipment computer models;
2) To determine, via computer simulations, the effect of the time between control decisions in the dynamic control of an HVAC system;
3) To determine, via computer simulations, dynamic HVAC operating strategies that will potentially reduce the HVAC system energy consumption.

The subject building for the project was the IBM National Marketing Division Headquarter's located in Atlanta, Georgia. The building is an 11-story structure that is used mainly for office space. A large computing center is located on the 11th floor. The load from this center represents a major portion of the cooling load throughout the entire year. The core zone load of the building is met by two variable air volume systems. The perimeter zones are handled by four constant volume air handling units. There are five water chillers available to meet the chilled water requirements for the building. Three of the chillers are centrifugal type chillers, while the remaining two chillers are reciprocating chillers with heat recovery capability. A two-celled, induced-draft cooling tower with two-speed fans is used to reject the heat from the chillers.

The computer algorithms that were developed for the modeling of the HVAC equipment (cooling tower, water chillers, air handling units, etc.) are described.

The results of the optimization study showed the importance of defining the operating ;limits for the HVAC equipment and the building comfort zone. The end results of this proejct were the identification and investigation of potential energy saving HVAC operating strategies and the availability of "reliable" equipment models.