Episode 50 of The Trigan Empire
The Heat Controller
aka Het kasteel in de bergen (Dutch title)
The Castle in the Mountains (Dutch title, translated)
Written by Mike Butterworth
Illustrated by Philip Corke
The Heat Controller was originally published in 8 instalments in issues 682 (8 February 1975) to 689 (29 March 1975) of Look and Learn magazine.
It is reprinted in Volume 4 of The Rise and Fall of the Trigan Empire (Rebellion).
Links
https://www.catawiki.com/en/l/58769643-wood-gerry-original-cover-in-direct-colors-the-trigan-empire-trigie-l-empire-de-trigan-1985
Plot summary (Dutch)