[rcheshire (Rowland)]

Has anyone considered modifying the airflow through the heat exchanger. Theoretically, when air is expanded into a plenum it cools. If airflow inside the cooler box is ducted through a narrow duct (between the vanes of a heat sink at the point of maximum cooling) and then expanded into the camera box would there be a further and measurable drop in temperature.

Rather than locate the fan over the heatsink (exchanger) place it to one side and cover the top of the heat sink with a plate to form a series of parallel ducts and channel the flow through the heatsink, expanding it into the cooler box.