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Dry-air mass and actual volume flow
Carry conservation on the dry-air basis when air density and measured volume flow change.
Open the complete sample →PE Mechanical: HVAC and Refrigeration · Foundations refresher library
Engineering foundations: beyond the handbook
Understand why a method applies, work a case, then choose a route under fresh conditions.
The NCEES PE Mechanical Reference Handbook is the supplied examination reference. No separate design standards are listed for PE Mechanical: HVAC and Refrigeration. Refresh physical behavior, modeling choices and equation applicability alongside handbook navigation.
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The list identifies the available refreshers. A concept being taught here does not mean it is absent from your examination reference.
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Open and closed system boundaries
Choose a batch-energy balance or a flow-energy balance from what crosses the boundary.
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Energy and moisture are separate balances
Use enthalpy for total coil load and humidity ratio for moisture removal on a common dry-air basis.
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Absolute pressure in compression ratios
Use absolute inlet and outlet pressures when forming a compressor pressure ratio.
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Equipment and system operating point
Find the flow where available head equals required head instead of reading equipment capacity alone.
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Heat-exchanger physical bounds
Test the requested heat transfer against capacity rates and inlet temperatures before using a detailed exchanger equation.
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COP and refrigeration energy conservation
Separate transferred cooling from input work and include both in condenser heat rejection.
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Fluid, shaft, and electrical power
Follow the power boundary through the pump and motor before applying efficiencies.
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Choose a response before opening the explanation. If the basis or assumption is unclear, revisit the worked case and follow its related lesson. If your reasoning fits, move to targeted practice with new conditions. A single learning check does not establish mastery or predict a passing result.
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