EngiRef / Thermodynamics Engineering Formula
First Law of Thermodynamics
First Law of Thermodynamics: Energy balance: change in internal energy equals heat added minus work done. A Laws formula in thermodynamics engineering.
Laws
Specification
- Name
- First Law of Thermodynamics
- Discipline
- thermodynamics
- Category
- Laws
- LaTeX
- \Delta U = Q - W
- Description
- Energy balance: change in internal energy equals heat added minus work done
- Conditions
- Sign convention: W is work done by the system
- Can solve for
- ΔU, Q, W
- Tags
- first law, energy, heat, work
Variables
| Symbol | Name | Unit | Si Unit | Imperial Unit |
|---|---|---|---|---|
| ΔU | Change in Internal Energy | J | J | BTU |
| Q | Heat Added | J | J | BTU |
| W | Work Done | J | J | BTU |
Common questions
- What is the First Law of Thermodynamics formula?
- Energy balance: change in internal energy equals heat added minus work done. It sits under Laws, Thermo engineering in the EngiRef reference.
- What do the symbols in the First Law of Thermodynamics formula mean?
- In First Law of Thermodynamics, ΔU is change in internal energy in J; Q is heat added in J; W is work done in J.
- When does the First Law of Thermodynamics formula apply?
- First Law of Thermodynamics holds under this condition: Sign convention: W is work done by the system.