Close to the end of our hot-box tests, we made a point of taking a couple photographs of the PSU with a FLIR camera set to take pictures at an IR resolution of 320x240 (76,800 pixels).
Outside the hot box.
Here you can see the load cables heating up since lots of amperes were passing through them during the full load tests.
The situation was pretty hot internally and right at the PSU's exhaust grill.
The PSU while delivering 2.2 kW inside the hot box.