The heat is one of the most problematic topics in sci-fi (especially military sci-fi, or space opera). Every single process onboard the space warship produce heat - unless, of course, you managed to change the laws of thermodynamic... but Gods usually don't need spaceships to battle each other
The only way you could get rid of heat in tghe vacuum of space - before your ship melt, or your crew be disabled by overheating - is to radiate heat outside. And, since the radiation of heat is not highly efficient process, you need REALLY big radiator surface to get rid of all those nasty gigawatts that your lasers, grasers & sidewalls spend.Considering the Honorverse, the heat problem is quite important, because Honorverse's ships tended to be almost inconceivable owerpowered. They spend so much energy, that their fusion reactors are, basically, stellar-fusion type devices, that could vaporise the ship instantly if containment would be breached. They operate the propulsion systems, that required enormous ammount of energy (gravity isn't really a cost-efficient force...), and their weaponry & defense systems are even worse. And - because no process could be 100% effective - they surely create AN AWFUL LOT OF HEAT during operations.
So the question is - how they got rid of all those waste heat?
Problem is, that the total surface area of Honorverse ships isn't nearly big enough to simply radiate this heat from the ship's skin. For example, the good old "Fearless" have a total surface area of no more than 51522 square meters. Even assuming that each square meter could radiate 300 kWt of thermal waste heat, the brave little cruiser could not radiate more than 15,4 gWt of heat. And, obviously, this is far from sufficient for the energies that we observe (just to mantain a 500g acceleration of 88000 tons of mass we would need literally exawatt-level).
So, we need REALLY BIG RADIATORS on Honorverse's ships. Problem is, that their sizes and shapes are already established.
But... we have one REALLY BIG part that each Honorverse's ship bound to have. The impeller wedge, which is literally hundreds of kilometers in size. And if we could - somehow - let the impeller to radiate all our hit...
MY IDEA: let's use the impeller wedge as part of REALLY BIG droplet radiator! The liquid droplets have the best surface area to volume ratio; they are perfect way of getiing rid of the heat (just spray the heated liquid overboard, let it cool down and scope the droplets).
Problem is, usually liquid droplet radiators aren't well-suited for high-G maneuvering. Simply speaking - you would lose a lot of droplets with each turn, i.te your radiation system would quickly run dry.
But... in Honorverse we have our magical gravitech!
We have tractor beams, areas of controlled gravity and other cool stuff. So, we could actually build the droplet radiator, that would work in high-G environment!So how the Honorverse's ship could cool itself? I imagine, that the spray the liquid - probably liquid alluminium or even copper - from their bow thickening directly into the impeller bands. For any structured objects this would means immediate disintegration, but the droplets would be fine even under tremendous gravity stresses.
The droplets are spreading through the wedge plane - thus turning the whole wedge into one enormous radiator. They are radiating their heat all along - the wedge clearly didn't affect that. The cooled coolant droplets are scooped by sort-of "gravity ramscoop" system on the stern - probably the system of wide-area tractor beams - and recycled through the ship's coolant system. Again.
Now, assuming the previous 300 mWt per square meter, we could have about 1500000 gigawatts of waste heat radiated from the average 100 km * 50 km impeller. This is more like it.
P.S. Still have a problem with spider-drive ships... their thermal radiation are, clearly, the problem. Even the average Alliance officer would not be able to overlook something that radiating more heat than average planet... Hm... their propulsion system are able to partially penetrate the Alpha Wall - so, is it possible that they use their gravity "legs" to transfer heat (in some form) into hyperspace to dissipate unnoticed?