380,520 Joules
That is;
Q = m×c×Δt
In the question above;
Mass of glass is 15.1 kg
Change in temperature = 45°C - 15 °C
= 30°C
Specific heat capacity of glass = 840 J/kg/°C
Therefore;
Quantity of heat, Q = 15.1 kg × 840 J/kg/°C × 30°C
= 380,520 Joules
Hence, it takes 380,520 Joules to heat up 15.1 kg of glass from 15°C to 45°C.