The Compressor Cycle method derives the required storage volume directly from the compressor's load/unload pattern. The effective net capacity is the fraction of the compressor's rated output consumed over a full cycle; the tank must store the air that accumulates during the unloaded phase so that system pressure stays within \(P_{load}\) to \(P_{unload}\).

\begin{equation}\label{eq:receiver-tank-compressor-cycle-size} V_{required} = \frac{Q_{comp} \cdot t_{load} \cdot t_{unload} \cdot P_{atm}} {60 \cdot (t_{load} + t_{unload}) \cdot (P_{unload} - P_{load})} \cdot k_{gal} \end{equation}

Derivation

The effective net capacity consumed per unit time is:

\begin{equation}\label{eq:receiver-tank-compressor-cycle-capacity} Q_{eff} = \frac{t_{load}}{t_{load} + t_{unload}} \cdot Q_{comp} \end{equation}

The volume (ft³) that must be stored during the unloaded phase is:

\begin{equation}\label{eq:receiver-tank-compressor-cycle-vcf} V_{cf} = \frac{Q_{eff} \cdot t_{unload} / 60}{(P_{unload} - P_{load}) / P_{atm}} \end{equation}

Converting to gallons gives \(V_{required} = V_{cf} \cdot k_{gal}\).

Symbols

\(V_{required}\)	Required receiver tank size (liquid storage volume) \([\unit{ \gallon}]\)
\(V_{cf}\)	Required storage volume (area storage volume) \([\unit{ \cubicFoot}]\)
\(Q_{comp}\)	Rated compressor capacity at full load \([\unit{ \cubicFoot\per\minute}]\)
\(Q_{eff}\)	Effective net capacity consumed per cycle \([\unit{ \cubicFoot\per\minute}]\)
\(\Delta P\)	Pressure band width ( \(P_{unload} - P_{load}\)) \([\unit{ \psi}]\)
\(t_{load}\)	Compressor loaded time per cycle \([\unit{ \minute}]\)
\(t_{unload}\)	Compressor unloaded time per cycle \([\unit{ \minute}]\)
\(P_{atm}\)	Atmospheric pressure \([\unit{ \psi}]\)
\(P_{unload}\)	Compressor unload (cut-out) pressure \([\unit{ \psi}]\)
\(P_{load}\)	Compressor full-load (cut-in) pressure \([\unit{ \psi}]\)
\(60\)	Seconds per minute conversion \([\unit{ \second\per\minute}]\)
\(k_{gal}\)	Gallons per cubic foot (7.48) \([\unit{ \gallon\per\cubicFoot}]\)

Returned intermediate results

In addition to \(V_{required}\), the calculation returns:

• effectiveCapacity ( \(Q_{eff}\)) — average flow delivered over a full cycle \([\unit{\cubicFoot\per\minute}]\)
• pressureChange ( \(\Delta P\)) — operating pressure band width \([\unit{\psi}]\)
• volumeCf ( \(V_{cf}\)) — required area storage volume before gallon conversion \([\unit{\cubicFoot}]\)