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Table 4 Expressions linking PR (Atsu et al. 2021; Bansal et al. 2021; Shrivastava et al. 2021)

From: Assessment and performance analysis of roof-mounted crystalline stand-alone photovoltaic (SAPV) system at selected sites in South Africa



Equation number


Performance ratio (PR)

\(\begin{aligned} {\text{PR}} & = \frac{{{\text{PV}}_{{{\text{outspecific}}}} }}{{{\text{GTI}}}} = \frac{{Y_{{\text{f}}} }}{{Y_{{\text{r}}} }} \\ & = {{\left( {\frac{{E_{{{\text{out}}}} }}{{P_{o} }}} \right)} \mathord{\left/ {\vphantom {{\left( {\frac{{E_{{{\text{out}}}} }}{{P_{o} }}} \right)} {\left( {\frac{{H_{{\text{i}}} }}{{G_{{{\text{i}},{\text{ref}}}} }}} \right)}}} \right. \kern-\nulldelimiterspace} {\left( {\frac{{H_{{\text{i}}} }}{{G_{{{\text{i}},{\text{ref}}}} }}} \right)}} \\ \end{aligned}\)



Final PV system yield (Yf)

\(Y_{{\text{f}}} = \frac{{E_{{{\text{out}}}} }}{{P_{o} }}\)



Reference yield (Yr)

\(Y_{{\text{r}}} = \frac{{H_{{\text{i}}} }}{{G_{{\text{i}}} }}\)



  1. Here, PVOUTspecific is the specific photovoltaic power output (kWh/kWp); GTI is the global tilted irradiance; Gi is the sum of direct, diffuse, and ground-reflected irradiance incidents upon an inclined surface parallel to the plane of the modules in the PV array, Hi is the in-plane irradiation kWh/m2, Eout is the energy output from PV system (AC) (kWh); Po is the array power rating, AC (kW)