Understanding HVAC Systems, Processes, and Performance Through Hands-On Exercises

Instructor:  David Sellers, PE, Facility Dynamics

The fundamental goals of HVAC are to move energy to or remove energy from occupied spaces using systems composed of energy-consuming/conversion equipment, such as fans, pumps, boilers, and compressors, and heat transfer equipment, like coils, heat exchangers, and chillers. These components work together to maintain clean, safe, comfortable, and productive indoor environments.

Understanding HVAC processes, whether for design, operation, or optimization, requires a grasp of both the physics of heat and fluid flow and the behavior of the machinery involved. Key physical principles include the equations of state for fluids, the conservation of mass and energy, and the hydraulic power equation. Engineers often rely on visual tools like charts and tables to simplify these complex relationships.

Using SketchUp models and guided tours of on-site mechanical spaces, participants will follow a parcel of air as it travels from a ballroom through several HVAC processes—from the air handling unit to the chilled water system and chiller, through the condenser water loop, and finally to the cooling tower. Along the way, they will apply theoretical concepts to real-world system interactions.

Interactive segments will reinforce learning, such as using psychrometric charts to analyze energy transfer and explore how modifying parameters can enhance system efficiency. Additional modules will introduce other performance and thermodynamic charts, building a practical foundation in HVAC principles.

This session is designed for beginners or non-technical attendees looking to understand HVAC basics without being overwhelmed. It’s equally beneficial for technically trained professionals returning to HVAC topics. Supplemental resources, such as references to the Honeywell Gray Manual, will be provided for continued learning.

Learning Objectives

1. Describe the fundamental concepts behind an HVAC load, such as sensible gains, latent gains, and sensible heat ratio.
2. Detail how the fundamental concepts behind an HVAC load impact the design parameters for the HVAC system serving the load.
3. Express how systems work together to maintain clean, safe, comfortable, and productive indoor environments.
4. Recognize some tools for evaluating HVAC processes and equipment, such as psychrometric charts and pump and fan curves.
5. Summarize the interactive nature of the various HVAC processes in an HVAC system.