. 2020 Aug 24;135:110254. doi: 10.1016/j.rser.2020.110254

Table 3.

The mathematical equations of PV/T with heat exchanger of galvanized steel system [67].

Description	Equations
Glass	$T_{i}^{n + 1} = T_{i}^{n} + \frac{λ_{υ} Δ t}{ρ_{v} c_{v}} [\frac{T_{i - 1}^{n} - T_{i}^{n} + T_{i + 1}^{n}}{{(Δ x)}^{2}}] + \frac{Q_{υ} ρ_{υ} \cdot c_{υ} \cdot Δ x Δ t}{λ_{υ}}$
Cell PV	$T_{i}^{n + 1} = T_{i}^{n} + \frac{λ_{P V} Δ t}{ρ_{P V} c_{P V}} [\frac{T_{i - 1}^{n} - T_{i}^{n} + T_{i + 1}^{n}}{{(Δ x)}^{2}}] + \frac{Q_{P V} ρ_{P V} \cdot c_{P V} \cdot Δ x Δ t}{λ_{P V}}$ $Q_{e l e} = τ_{g} A_{c e l} η_{r e f} \exp [β (T_{c e l} - T_{r e f})]$
Tedlar	$T_{i}^{n + 1} = T_{i}^{n} + \frac{λ_{T e d} Δ t}{ρ_{T e d} c_{T e d}} [\frac{T_{i - 1}^{n} - T_{i}^{n} + T_{i + 1}^{n}}{{(Δ x)}^{2}}] + \frac{Q_{T e d} ρ_{T e d} \cdot c_{T e d} \cdot Δ x Δ t}{λ_{T e d}}$ $Q_{T e d} = \frac{h_{c o n d P V - T e d}}{ρ_{T e d} \cdot c_{T e d} \cdot \frac{Δ x}{2}} (T_{T e d} - T_{P V}) - \frac{h_{c o n d T e d - P}}{ρ_{T e d} \cdot c_{T e d} \cdot \frac{Δ x}{2}} (T_{P} - T_{T e d})$
Tube	$T_{i}^{n + 1} = T_{i}^{n} + \frac{λ_{t u b} Δ t}{ρ_{t} c_{t}} [\frac{T_{i - 1}^{n} - T_{i}^{n} + T_{i + 1}^{n}}{{(Δ x)}^{2}}] + \frac{Q_{t} ρ_{t} \cdot c_{t} \cdot Δ x Δ t}{λ_{t u b}}$ $Q_{t} = \frac{h_{c o n d p - t u b}}{ρ_{t} \cdot c_{t} \cdot \frac{Δ x}{2}} (T_{t u b} - T_{p}) - \frac{h_{c o n v t u b - f}}{ρ_{t} \cdot c_{t} \cdot \frac{Δ x}{2}} (T_{f} - T_{t u b}) - \frac{h_{c o n d t u b - i s o}}{ρ_{t} \cdot c_{t} \cdot \frac{Δ x}{2}} (T_{i s o} - T_{t u b})$
Fluid	$\frac{m_{f} c_{f}}{S} \frac{d T_{f}}{d t} + \frac{m c_{f}}{l} \frac{d T_{f}}{d y} = h_{c o n v f} (T_{t u b} - T_{f})$
Useful heat gain	$Q_{u s e} = A_{c} F_{R} {(τ α)}_{PV} G$ $Q_{u s e} = - A_{c} F_{R} U_{pv - a} (T_{i n} - T_{a})$
PV/T efficiency	$Q_{u s e} = F_{R} [(τ α) - U_{L} \frac{T_{s} - T_{a m b}}{G}]$