①The heat absorbed (or released) during a process with a temperature change of Δt is denoted as Q (J).
Q = c · m · Δt.
Qabsorbed = c · m · (t - t0)
Qreleased = c · m · (t0 - t)
(t0 is the initial temperature; t is the final temperature)
Where c is the specific heat capacity related to the process.
The unit of heat is the same as that of work and energy. In the International System of Units (SI), the unit of heat is the joule (J), named in honor of scientist James Joule. Historically, the calorie (cal) was also used as an auxiliary unit of energy, where 1 cal = 4.184 J.
Note: 1 kilocalorie = 1000 calories = 1000 Calories = 4184 joules = 4.184 kilojoules
The balance maintained between the heat absorbed, released, and stored in a region over a certain period.
ΔT = (t1 - t0)
②The formula for calculating the heat released by the complete combustion of solid fuels: Qreleased = mq. The formula for calculating the heat released by the complete combustion of gaseous fuels: Q = Vq. Here, Q represents heat (J), q represents the calorific value (J/kg), m represents the mass of solid fuel (kg), and V represents the volume of gaseous fuel (m^3).
q = Qreleased/m (for solids); q = Qreleased/V (for gases)
W = Qreleased = qm = Qreleased/m; W = Qreleased = qV = Qreleased/V (W: total work)
(Calorific value is related to pressure)
SI Units:
Q — Heat released by the complete combustion of a fuel — Joule (J)
m — Mass of the fuel — Kilogram (kg)
q — Calorific value of the fuel — Joule per kilogram (J/kg)
Formula for Thermal Energy Calculation
Q = Δt · m · C
(Specific heat capacity is C, mass is m, Δt is the temperature difference)