Excellent points. This should have been basic engineering.
Seems to me, that some energy must be expended, in order to remove moisture from the Titan sub atmosphere; plus, energy expended in order to heat the sub - given that the seawater temperature at depth below 4,000 ft is 1 - 4 F deg.
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Cooling System - Gemini Capsule
http://geminiguide.com/Systems/cooling.html#SUIT_And_CABIN_TEMP_Controls
EXCERPT:
The cooling circuit in which the cooling system operates is dependent upon the temperature loads generated by the equipment, spacecraft phase of flight and the temperature within the spacecraft cabin.
Cooling is provided throughout the mission up to pre-retrograde firing. At this time the coolant pump packages are Jettisoned with the adapter equipment section, terminating spacecraft cooling.
Spacecraft 5 and 8 through 12 require both loops to be operated contlnuously. In spacecraft 6 the primary circuit operates continuously providing the required cooling during low temperature loads. The secondary circuit is used, in conjunction with the primly circuit, during phases of high temperature loads; namely - launch, rendezvous, and pre-retrograde.
Under normal heat loads, the number 1 pump in the primary circuit provides the required cooling. Under peak heat loads, the number 1 pump in the secondary circuit is used with the primary circuit number 1 pump to provide maximum cooling. In the event of a number 1 pump malfunction in either circuit, the number 2 pump in that circuit is used.
In the event of both pumps failing in one circuit, both pumps of the remaining circuit can be used to provide the required cooling. (Spacecraft 6 does not have the number 2 pump in either circuit.)
