How Heat Moves in Plant & Environmental Sciences

roof of PES
We're on the roof with John to learn how the building is heated. What a view!

UC Davis Campus Buildings: An Untold Story 

Ever wonder what goes on behind the scenes in each building on campus? What's in the basement and mechanical rooms, how do the heating and air conditioning systems work, and what resources heat and cool a building on campus? Where does it all come from and where does it all go?  To answer these questions, our Energy Project Manager John Coon, took us on an in-depth tour of the Plant and Environmental Sciences building. 

Building Spotlight: Plant and Environmental Sciences 

Built in 2002, the Plant and Environmental Sciences (PES) building is a three story building on the north side of campus.  PES has 260 different rooms and is home to two different departments.  

  • Plant Sciences
  • Land, Air and Water Resources

The PES building is primarily used as laboratory space; however, it also contains office, administration and classroom space as well. The various room uses are measured in ASF (Assignable Square Footage) which is the sum of the building spaces available for a specific use, excluding closets, mechanical, services, etc.

room breakdown 

Due to the heavy percentage of labs in this building, the mechanics of the chilled water, steam and electricity are more geared towards industrial use. Buildings that include laboratory spaces have an increased energy use due to the massive amount of required ventilation.  The air coming into the lab has to be 100% outside air, and then it must completely leave the building, through large exhaust vents on the roof like the one pictured below. These massive structures project the air that's already circulated through the building up into the atmosphere so it cannot affect people below.


On our tour of the building, we went into the basement to see how the building is heated and cooled. In the photo below, you can see a pipe labeled "High-Pressure Steam". This hot steam is coming from the Central Heating and Cooling Plant (CHCP), which then goes through a heat exchanger indicated by the orange arrows. The steam condenses in the heat exchanger to make hot water and the steam condensate returns to the central plant. 

High-pressure steam comes from the Central Heating and Cooling Plant (CHCP), which then goes through a heat exchanger.


The heated hot water supply circulates to the roof of the building to an air handler unit responsible for heating the building, as shown in the photo below. 

On the roof of PES, the heated hot water supply circulates to an air handler unit responsible for heating the building

    The hot water supply flows into the air handler unit. In the air handler, heat transfers from the water to the air, and the water returns back to the basement of the building to be reused again. The resulting warm air is circulated throughout the building as heating, and this is what you feel coming out of the vents


    Want to learn more?  

    Each building on campus uses energy differently, and the amount of energy it uses depends on the: 

    • Age of the building (building envelope)
    • Air temperature outside
    • How the building is used (laboratory, offices, classrooms, lecture hall)
    • Number and type of windows
    • HVAC schedules (Heating, Ventilation and Air Conditioning) 

    On our CEED website (Campus Energy Education Dashboard) we have a detailed map of campus pinpointing buildings and their energy usage. The different energy commodities and their usage that we keep track of at the Energy Conservation Office are electricity, steam, and chilled water.  We categorize each building on campus based on its Energy Use Intensity which is a building's annual energy use divided by its square footage.   



    You are able to select individual buildings and see various different types of statistics specific to that building, compare buildings to one another, and see energy supply, demand, and cost over periods of time. 



    CEED (Campus Energy Education Dashboard) is an awesome tool to find out more about the buildings you use on a regular basis!