A 39-chapter interactive guide to HVAC systems — fundamentals and psychrometrics, residential and multi-family systems, commercial and industrial plants, VAV and chilled-water distribution, ventilation and energy recovery, controls and building automation, equipment schedules and construction documentation, and technician fundamentals and troubleshooting. Every reference drawing gets its own full-size slide so schedules, legends, and dimensions stay legible.
Chapters 1–6 build the fundamentals: what HVAC means, the residential refrigerant cycle, whole-house airflow paths, a mechanical-room furnace/water-heater layout, and the psychrometric chart processes behind every system. Chapters 7–19 cover residential, multi-family, commercial, and industrial systems — split systems, chiller/FCU and DOAS apartment systems, commercial VAV plants, and industrial/warehouse ventilation with equipment schedules. Chapters 20–21 cover VAV airflow and reverse-return chilled-water piping. Chapters 22–26 cover ventilation, ASHRAE 62.1 outdoor-air calculations, energy recovery, and CO2-based demand-controlled ventilation. Chapters 27–31 cover feedback control loops, AHU sequences of operation, and BAS network architecture. Chapters 32–36 cover equipment schedule formats and full construction documentation sets. Chapters 37–39 close with electrical fundamentals, troubleshooting techniques, and a unifying control-sequence diagram.
Use the Prev / Next buttons at the bottom, or press the arrow keys on your keyboard. Click the ☰ menu button in the top-right to open the table of contents and jump to any section. Each chapter's reference figure follows immediately after its text as its own dedicated slide, so you can view the full diagram, schedule, or chart at a readable size before moving to the next chapter.
HVAC designers and mechanical engineers who want a structured visual reference spanning residential through industrial scale; controls and BAS technicians learning network architecture, sequences of operation, and feedback loops; construction and estimating professionals who need to read equipment schedules and documentation sets fluently; and engineering students and FE/PE exam candidates studying psychrometrics, ventilation code, and system fundamentals through complete, real-world diagrams.
Residential HVAC typically uses a split system or heat pump with a single indoor air handler and outdoor condenser serving the whole home through one duct system. Commercial HVAC scales this up with rooftop air handling units (AHUs), central chiller/boiler plants, and VAV terminal units that give independent temperature control to many separate zones from one central air source.
A constant-volume system delivers a fixed airflow to a zone and varies only supply air temperature to meet load. A VAV (variable air volume) system holds supply air temperature relatively constant and instead modulates the volume of air delivered to each zone through a VAV box, often adding reheat when a zone needs heat at minimum airflow — giving much finer, more energy-efficient zone-by-zone control.
An Energy Recovery Ventilator (ERV) transfers heat and moisture between outgoing exhaust air and incoming outdoor air, pre-conditioning ventilation air before it reaches the mechanical coils. Demand Controlled Ventilation (DCV) uses CO2 or occupancy sensors to modulate outdoor airflow down when a space is lightly occupied, rather than always ventilating for full design occupancy — both reduce the mechanical cooling and heating load tied to ventilation air.
A BAS is organized into three layers: a supervisory layer (BAS server and operator workstation over BACnet/IP), a control layer (DDC controllers for each AHU, chiller, boiler, and VAV box communicating over BACnet MS/TP or Modbus), and a field device layer (sensors and actuators wired to each DDC controller over a local fieldbus).
Most mechanical equipment schedules share a common column set: a tag that uniquely identifies the unit across every drawing sheet, a type/description, capacity (tons, kW, or GPM depending on equipment type), airflow (CFM), voltage/electrical for coordination with the electrical engineer, and notes/remarks — the same format is used whether scheduling an AHU, a pump, a rooftop unit, or a VAV terminal.
Disclaimer: This guide summarizes general HVAC design and system concepts, including illustrative worked examples, for educational purposes only. All projects, equipment schedules, and capacities shown are representative examples, not specifications for any real project. Always consult a licensed mechanical engineer and the applicable ASHRAE, SMACNA, and building/mechanical code requirements for actual project design.