Explain how trending historical data from a BAS can be used to identify energy waste and optimize system performance.

Trending historical data from a Building Automation System (BAS) allows for the analysis of system performance over time, enabling the identification of energy waste and optimization of system operation. Trending involves collecting data from sensors and equipment over a specified period, such as hours, days, weeks, or months, and storing it in a database. This historical data can then be analyzed to identify patterns, trends, and anomalies. One way to identify energy waste is to analyze temperature trends. For example, if the temperature in a zone is consistently higher or lower than the setpoint, it indicates that the HVAC system is not operating efficiently. This could be due to a malfunctioning sensor, a poorly tuned control loop, or a problem with the equipment. By analyzing the temperature trends, the cause of the problem can be identified and corrected. Another way to identify energy waste is to analyze equipment runtime trends. For example, if a pump or fan is running for longer periods than necessary, it indicates that the equipment is consuming more energy than it should. This could be due to an inefficient control strategy or a problem with the equipment. By analyzing the runtime trends, the cause of the problem can be identified and corrected. Trending can also be used to optimize system performance by identifying opportunities for improvement. For example, by analyzing occupancy patterns, the HVAC system can be scheduled to operate only when the building is occupied, reducing energy consumption during unoccupied periods. By analyzing weather data, the HVAC system can be adjusted to compensate for changes in outdoor temperature and humidity, improving comfort and efficiency. To effectively trend data, it's necessary to choose relevant data points, set appropriate trending intervals, and establish baseline performance metrics. Regular review and analysis of the trends are crucial to identifying and addressing any issues in a timely manner.