A complete engineering resource for HVAC design and commissioning professionals. Covers Manual J residential load calculations, Manual D duct sizing, Manual S equipment selection, ASHRAE 62.1/62.2 ventilation requirements, psychrometric analysis, and chilled water/VRF system design — with interactive simulators for refrigeration cycles, zone control, and air handling unit processes.
Built for HVAC design engineers, mechanical contractors, commissioning agents, and PE Mechanical exam candidates. Covers the thermal and fluid systems calculations tested on the PE Mechanical (HVAC & Refrigeration) depth exam.
Interactive 3D walkthrough of a 3-story commercial building. Explore AHUs, VAV boxes, chiller plant, boiler, hydronic piping, ductwork, and BAS controllers with ASHRAE references.
Split-screen interactive designer for a complete central-plant commercial HVAC system. Explore a 3D building — rooftop AHU, DOAS/energy recovery, cooling tower, mechanical-room chiller/boiler/pumps, VAV boxes with reheat, ductwork, diffusers, and BAS sensors — alongside a connected system diagram (airside loop + chilled/condenser/hot water loops + controls). Click any component or node to cross-highlight across both views, and toggle to a top-down Floor Plan with duct/pipe runs. Covers ASHRAE 90.1, 62.1, 15, and 55.
Split-screen 3D building viewer + live system schematic. Click any device — AHU, VAV, DDC, chiller, boiler, pump — to cross-highlight across both panels. Covers BACnet controls, CHW/HHW piping, and air distribution per ASHRAE 90.1.
Animated P-h diagram for the vapor-compression cycle. Adjust evap/cond temps, superheat, and subcooling — watch state points shift and COP update live. Supports R-410A, R-32, R-22.
Interactive psychrometric chart with animated process lines. Simulate heating, cooling/dehumidification, humidification, and air mixing between plotted states.
Multi-zone thermostat simulation over a 24-hour day. Set setpoints and occupancy per zone, then watch the HVAC system cycle as outdoor temps change and internal gains build up.
Animated SVG duct tree from AHU to diffusers. Color-coded velocity bands flag over- and undersized ducts. Shows CFM, velocity (fpm), and pressure drop per segment.
Two-chiller plant with cooling tower and primary/secondary pumps. Vary building load 0–100% and watch the sequencing logic stage equipment on/off. Tracks kW/ton efficiency.
Animated AHU cross-section with airflow particles through mixed-air dampers, preheat, cooling coil, supply fan, and reheat. Temperatures update at every section in real time.
Manual J simplified cooling load: envelope conduction, solar gain, occupant loads, equipment, and lighting. Outputs tons and BTU/hr.
Heating loss by component: walls, ceiling, floor, windows, and infiltration. Enter 99% design temps. Outputs MBH and BTU/hr.
Rule-of-thumb tonnage sizing using ft²/ton zone factors and construction efficiency adjustments. Gives min/max range.
ACCA Manual D equal friction method. Inputs: CFM and friction rate. Outputs round diameter, standard size, velocity, and pressure drop.
Supply CFM from BTU/hr load and ΔT. Adds ASHRAE 62.1 minimum outdoor air by space type. Outputs CFM/ton and OA flow.
From dry-bulb and RH: wet-bulb, dew point, humidity ratio, enthalpy, and specific volume using Magnus formula.
ASHRAE 62.1 outdoor air requirements by space type. People and area components, zone OA flow, CFM/person and CFM/ft².
Commercial chiller plant capacity: building loads, diversity, redundancy. Outputs tons, kW, kW/ton, CHW GPM, and cooling tower sizing.
Boiler output from heat loss + DHW loads with piping loss and redundancy. Fuel type, AFUE, annual fuel cost, and hot water GPM.
ACR copper pipe sizes for liquid, suction, and discharge lines. Supports R-410A, R-32, R-22, R-134a, and R-407C. Velocity check included.
Fan and motor sizing from CFM and total static pressure. BHP, motor kW, W/CFM efficacy, altitude correction, and standard motor size.
Hazen-Williams pipe sizing for chilled/hot water systems. Velocity check, friction loss, pump head, glycol correction, and BTU/hr capacity.
Instantly convert between BTU/hr, tons of refrigeration, kW, MBH, and kcal/hr. Live 5-way conversion with reference table of common HVAC equipment capacities.
HVAC spans an engineering license track and a strong technician certification/licensing track. This overview covers the FE and PE Mechanical (HVAC & Refrigeration) path, the federally required EPA 608, NATE technician certification, and state HVAC/mechanical trade licenses.
FE Mechanical prep: thermodynamics, fluids, heat transfer and HVAC/refrigeration — first step toward the PE.
PE Mechanical: HVAC & Refrigeration prep: psychrometrics, loads, air distribution, hydronics and refrigeration.
EPA 608 prep: the federally required refrigerant certification — Core plus Type I/II/III (or Universal).
NATE certification prep: the leading HVAC technician credential — AC, heat pumps, heating, and air distribution.
State HVAC license prep: mechanical (IMC) code, load/duct calcs, combustion/venting and refrigeration — journeyman to contractor.
Interactive 14-section ASHRAE reference guide covering psychrometrics, cooling/heating load calculations, duct sizing, refrigeration cycle, chillers, VRF systems, ASHRAE 62.1 ventilation, and energy codes.
Comprehensive HVAC licensing exam preparation guide covering load calculations, equipment selection, refrigeration cycles, and code requirements.