The formula to calculate the design power of a biomass cookstove is:

\[ P_d = 0.7 \cdot (P_c + P_v) \]

Where:

• \(P_d\) is the design power in KCal/hr.
• \(P_c\) is the charcoal power in KCal/hr.
• \(P_v\) is the max volatile in KCal/hr.