Reversible computing paper talking about limiting heat generation This can be done as well as spacing out the system to be less dense.
Article exploring limits of computing
Another PHd dissertation that analyses the future limits to computing and cooling
Typical passive emission 3.5 * 10 ** 22 flux bits/s cm**2 (about 100W per square centimeter)
Drexler’s fractal plumbing 3.8 * 10 ** 24 flux bits/s cm**2 (about 10-100KW of heat removed per square centimeter)
Slow atomic ballistic (theoretical 1 m/s coolant) flux 10 ** 26 bits/s cm**2
Fast atomic ballistic (theoretical relativistic speed coolant) flux 3 * 10 ** 33 bits/s cm**2
Quantum maximum 5 * 10 ** 40 flux bits/s cm**2
Existing cooling is at about 1KW per square centimeter using microchannels with force d liquid convection (David Tuckerman)

Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
Known for identifying cutting edge technologies, he is currently a Co-Founder of a startup and fundraiser for high potential early-stage companies. He is the Head of Research for Allocations for deep technology investments and an Angel Investor at Space Angels.
A frequent speaker at corporations, he has been a TEDx speaker, a Singularity University speaker and guest at numerous interviews for radio and podcasts. He is open to public speaking and advising engagements.