Richard Lupoff (1987). Sun’s End. Grafton.

The last thing computer circuit planner Daniel Kitajima remembered was being hit by a crane at an orbital construction site. Waking up 80 years later in 2089 he found that most of his body had been destroyed… but he had survived. A group of doctors had constructed an artificial body that gave him superhuman strength, the ability to survive without food or air, the powers of radar and infrared vision. All Daniel wanted to do was resume a normal life. But his new-found strengths had attracted the attention of powerful people with a devastating secret – that the solar system had only a few centuries to live.