Me testing how fast the induction cooker boils 1L of water. By my reckoning it takes approx 2:18 to boil from 21° C.
Works out at about 75% thermal efficiency, and costs around 2.9c (AUD). Not bad.
Maths:
79° difference = 79° * 4.1813J/(g * K) * 1000g = 330,322.7 J
330,322.7J / 138s = 2,359W output
The hob I used specifies 3.2kW, so it's 2,393 / 3200 = 75% efficient.
3,200W * 138s = 441,600J input
441,600J / 3,600,000 = 0.123kWh
I pay roughly 24c/kWh, so 0.123kWh * 24c = 2.9c
FWIW the cooktop is a Westinghouse PHN644DU, connected to a 32amp circuit at 240V.
