## 1 Introduction
[13] investigated experimentally two configurations of a ventilated opaque double-skin facade (parietodynamic wall) based on hollow clay bricks. The laboratory tests for the supply-air facade configuration showed that, depending on the airflow rate, a preheating efficiency of 9 to 20% can be achieved. The heat loss reduction for the exhaust-air facade configuration was measured as being between 43 and 68%. [PERSON] and [PERSON] [19] investigated through experiments and numerical simulations the performance of a solar dynamic buffer zone (SDBZ) within a curtain wall system. This SDBZ is a facade system capable of collecting heat from outside. The authors found that the SDBZ developed a thermal efficiency of 25 to 30%, placing this system in the medium range for solar air collectors. * Performance indicators  
Many indicator definitions can be used to evaluate the thermal performance of ventilated solar facades under different operating configurations. \[\text{A}:\ \eta_{A}=\frac{T_{out}-T_{ext}}{T_{in}-T_{ext}} \tag{1}\]  
\[\text{B}:\ \eta_{B}=\frac{Q_{u}}{AI} \tag{2}\]  
where \(Q_{u}(W)\), the useful heat gain, is given by the following equation:  
\[Q_{u}=\dot{m}C_{p}(T_{out}-T_{in}) \tag{3}\]  
where \(\dot{m}\) (kg\(\cdot\)s\({}^{-1}\)) is the mass flow rate, \(C_{p}\) (\(\cdot\)kg\({}^{-1}\cdot\)K\({}^{-1}\)) is the specific heat capacity of the air, and \(T_{out}(^{\circ}\)C). and \(T_{in}(^{\circ}\)C). are, respectively, the air temperature at the outlet and the \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Type of Solar Wall** & **References** & **Operating** & **Operating** & **Approach** & **Ventilated Air** & **Thermal** \\  & **Mode** & **Condition** & **Condition** & **Chavity** & **Performance** \\ \hline SAF & _[PERSON] and A._ & natural & & & & \\ _(Double-skin facade)_ & _[PERSON]_[11] & convection & steady & numerical & 50 mm & A = 80 to 85\% \\ \hline IAC & _[PERSON]_ et al. [20] & natural & & & & \\ _(Trombe wall)_ & _[PERSON]_ et al. [20] & convection & dynamic & numerical & 45 mm & C = 20 to 30\% \\ \hline SAF & _[PERSON]_ et al. & forced & & & & \\ _(Parietodynamic_ & [21] & convection & dynamic & & & \\ _window)_ & _[PERSON]_ et al. & forced & & & & \\ _(Parietodynamic wall)_ & _[PERSON]_ et al. & forced & & & & \\ _(Parietodynamic wall)_ & _[PERSON]_ et al. [22] & & & & & \\ \hline IAC & _[PERSON]_ et al. [22] & & & & & \\ _(Trombe wall)_ & _[PERSON]_ et al. [23] & & & & & \\ _(Trombe wall)_ & _[PERSON]_ et al. [23] & & & & & \\ \hline IAC & _Jaber and Ajib_ & & & & & \\ _(Trombe wall)_ & _[PERSON]_ et al. [24] & & & & & \\ \hline SAF & _[PERSON] and_ & forced & & & & \\ _(Solar dynamic_ & _Pressnail_ [19] & convection & steady & experimental & & \\ _buffer zone)_ & _[PERSON] and_ & _[PERSON]_ [19] & & & & \\ \hline SAF & _[PERSON] and_ & forced & & & & \\ _(Solar dynamic_ & _Pressnail_ [25] & & convection & & & \\ _buffer zone)_ & _[PERSON] and_ & _[PERSON]_ [25] & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of a selection of solar wall configurations. inlet of the VSW. Moreover, \(I\) is the irradiance (W\(\cdot\)m\({}^{-2}\)) and A(m\({}^{2}\)) is the surface area of the VSW.