An HVAC "process" is designed to offset loads and maintain comfort or operational conditions. Supply air is delivered at a state meant to address design loads. As air leaves the coil it experiences different loads traveling through the ducting, downstream treatment, and in the space that gradually change its state to what is measured at the thermostat. Actual loads are dynamic and seldom remain at design conditions. in this module we will use the psych chart to helps us visualize how loads can differ from design and what strategies can help improve operation. We will also introduce several key psychrometric equations to calculate HVAC energy using CFM and state changes in either temperature or enthalpy. When using these equations we always need to make sure the assumption of "standard air" applies.
Learning Objectives
Upon completion of this course, attendees will be able to:
- Relate the psychometric chart to actual building systems and loads;
- Understand and calculate the energy used through different processes and cycles;
- Identify problems or energy savings opportunities through setpoint changes.
