Saving Energy by Recommissioning Buildings

My project concerns the building recommissioning process, specifically with building 192, "Engineering IV". I primarily investigated the building's VAV-box and HHW-CHW systems.

About Me

Alex Martinez

Mechanical Engineering

My name is Alex Martinez, I’m from Rocklin California, and I am a fourth year mechanical engineering student. Some of my hobbies include playing soccer, spike ball, and video games.  I have always enjoyed my thermodynamics classes and that led me to apply for this project.

My project involves investigating some of the major building systems in Engineering IV and considering how to make the building more energy efficient. With the help of my sponsor Professor Keller and Dr. McDaniel, I was able to put together something that I am proud of.

Acknowledgements

Special thanks to Professor Keller for selecting me for this project and supplying guidance throughout. Also, thank you to Dr. McDaniel for offering his expertise and helping with my analysis.

Our/My Project Video (optional)

Saving Energy by Recommissioning Buildings

Introduction

Problem Statement

Buildings are major consumers of energy and recommissioning buildings is an important step in maintaining building performance and overall sustainability.

Plan

  • Visit site and compare installed equipment to mechanical drawings and schedules
  • Organize findings into living document
  • Acquire and analyze building operation data
  • Determine problems and inefficiencies within building
  • Offer solutions to management

Screenshot of findings log

My primary job for this project involved investigating the operations of variable air volume boxes and the buildings heating hot water and chilled water system.

Variable Air Volume (VAV) box

VAV Study

Engineering IV utilizes an extensive system variable air volume (VAV) boxes to create separate heating and cooling zones in the building. To determine the efficacy of the individual VAV boxes, we acquired data over a 27-day period. After analyzing the data, we found that there were 5 VAV boxes that operated far from their respective setpoints with the most extreme case being VAV-333.  

Data Analysis

The above figure is a normalized Air Flow vs. Time chart for VAV-333. The setpoint is in red, and the actual flow, in blue, clearly falls short of that setpoint. Dampers are constricting airflow, making it difficult to control the temperature in the zone.

Shown above is the Temperature vs. Time chart for VAV-333. Once again, the setpoint is in red, and the recorded value does not match at all. The zone is reacting to the outside temperature rather than any HVAC control system. Conditioned air is being supplied, but the dampers are preventing its flow leading to wasted energy and dissatisfied occupants.

Zone Mapping

To make the analysis useful, we needed to understand where each zone (and associated VAV box) is within the building, so we created a zone map for the whole of Engineering IV. Unfortunately, the VAV labels on the mechanical drawings differ from the labels from the collected data. We need to contact the data collection agency to make our findings more useful.

HHW-CHW Study

To analyze the activity of the Heating Hot Water and Chilled Water system (HHW & CHW), we looked at the system operation across a 26-day period. The focus of this investigation was to monitor supply and return temperatures and pump operations.                                      

Findings

The data showed no signs of major inefficiencies in the pumping system. The hot water supply is around 180 °F which matches both the mechanical plans and sequence of operation (SOO). Furthermore, the supply and return temperatures are consistent from day-to-day for both the CHW and HHW loops. Also, both hot water pumps followed lead/lag procedure as outlined in the SOO. Seeing as this system is operating without glaring issues, we looked to another building system.

Going Forward

With the time we had for this project, we could only investigate the HHW-CHW system and VAV box systems to monitor efficiency. If I had more time, I would have moved finalized VAV identification and moved on to analyzing AHU operation.

Although out of the scope of this project, another task that would greatly benefit this building would updating a variety of documents. The mechanical schedules, drawings, and naming conventions for this building are strewn with inconsistencies and error.

Share

Share on facebook
Share on twitter
Share on linkedin

Coronavirus Update and Resources