A heater warms up water using butane, with a heating value of *p _{c}*=MJ/kg, and it has an efficiency of

**b)***q*, fuel consumption in grams per second._{comb}**c)***c*, cost in €, and*m*mass of the fuel consumed during a time frame of_{comb}*t*=min.

**a)**\[P=\frac{E}{t}=\frac{Cp*m*Δt}{t}=Cp*q*ρ*Δt\]*P=*W

Note:ρ represents water's density, which is ρ=1kg/L-
**b)**\[q_{comb}=\frac{m_{b}}{t_{b}}=\frac{m_{b}*P_{b}}{E_{b}}=\frac{m_{b}*P_{b}}{p_{c}*m_{b}}=\frac{P}{p_{c}*η}=\frac{Cp*q*ρ*Δt}{p_{c}*η}\]*\[q_{comb}=\]*g/s

Note:ρ represents water's density, which is ρ=1kg/L -
**c)**\[c=\frac{m_{comb}*c_{b}}{m_{b}}→m_{comb}=?→m_{comb}=q_{comb}*t=\frac{Cp*q*ρ*Δt*t}{p_{c}*η}\]\[m_{comb}=\]kg

\[c=\frac{m_{comb}*c_{b}}{m_{b}}\]\[c=\]€

Note:ρ represents water's density, which is ρ=1kg/L