Its not nessiarly the heat that kills eletronics but thermal stresses… if you keep your components at the same tempature all the time, i.e turned on all the time so long as they are below their thermal overlaod setpoint you will be ok.. it’s the heating up and cooling down of eletronics that kills them, the thermal stresses palced on the solderjoints will cause them to break over a period of time. The trick is to minimize the amount of thermal stress, and by adding a fan it will do wonders to keep your components as close to room tempature as possible. In my last job, we would have servers up for years, and they ran at about 90 degrees or so… but this was never an issue sense the computers were never turned off. And with my current job we have eletronics that never get turned off and they have been running for 10+ years now.and operate ad 90-100 degrees or so, and no problems with any of them.
What I would recommend doing is build your av rack, and built it with a 4 inch clearance and get 2 fans one for intake and one for exhaust. This should keep your reciever very cool and you should have no problem at all, if you add a fan you can almost negate the clearance that the manufacture reccomends, sense the manufactures are not planning on you adding fans, they are just planning on convection to cool the fan..
Hope this helps.
