2017 ASHRAE Annual Conference

Automated tools facilitate an ongoing commissioning process to improve occupant comfort, ensure the persistence of correct system operation and reduce energy consumption. These tools decrease the time and the skill level required to carry out necessary quality assurance measures, and as a result they enable more thorough testing of building heating, ventilating and air-conditioning (HVAC) systems. This paper describes the algorithm developed by the U.S. National Institute of Standards and Technology (NIST) to analyze chiller loops and presents the results of a passive monitoring investigation using field data obtained from BACnet controllers and field validation of the findings. The tool was successful in detecting faults in system operation in its first field implementation for performance monitoring.

Design of chilled water plants has a very large impact on building energy uses and energy operating costs. This paper proposes a design tool for optimal design of chilled water plants. The tool that integrates system models with a genetic algorithm optimization solver minimizes the life cycle cost by finding the design variables such as chilled water and condenser piping diameters, chilled and condenser water temperature differences and chilled water supply temperature. The proposed modeling methods depend on detailed cooling load analysis and head and energy calculations. The pump head calculations including piping, all fittings, valves, and devices are achieved by using the Darcy-Weisbach equation with given flow parameters. The energy calculations are done by using generic chiller, fan, and pump models. The hourly cooling loads need to be obtained from any energy simulation software. The method is tested on an existing three-story, eighty-eight thousand square foot building.

A preliminary evaluation of the performance of a consumer-based control system was conducted by the Oak Ridge National Laboratory (ORNL) and Southwest Gas as part of a cooperative research and development agreement (CRADA) authorized by the Department of Energy (DOE) (Mahderekal et al. (2013). The goal of the research was to evaluate the low-cost approach as a solution for implementing a supervisory control system for a residential gas-operated heat pump. This technical paper explains the research process. A robust data set was produced that allowed detailed assessment of the reliability and the operational performance of the newly developed control system. Experiences gained from the test provided important points of improvement for subsequent evolution of the heat pump technology.