Spacecraft radiate infrared energy into space to keep systems from overheating. There are other forms of energy emitted by spacecraft as well. Generally, the energy emitted is in the form of electromagnetic radiation, unless actual matter is leaving the spacecraft. Sound can be created by a spacecraft, but will not travel through space. Spacecraft emit radio waves, purposely broadcasting them back to Earth for communication with Earth.
Some ships emit light.
Other forms of electromagnetic energy could be radiated incidentally to high power operations on the ship.