[Exeric]

You're doing a fantastic job analyzing and documenting with numbers and graphs your results. Kudos!

I think you're right that getting the water to condense is where a lot of heat is released. It's a hard nut to crack without some kind of heat pump arrangement. But I think I have come up with an idea that "might" work. My first thought was that you could just change the room air ducting so that it uses outside cold air to chill the heated dryer air in the exchanger. The dryer would still heat the room air and exhaust the less hot less humid air to the room. But the more I thought about the more it seems like this idea would end up as an energy wash. You definitely would get more condensation this way because you would be using much colder air to chill the dryer air. But most of that heat released from condensation would be used to heat the outside air. Soooo, in theory its pretty much a wash.

But what if you used the outside air in the heat exchanger just to cool the hot air to just above the dew point? Since most of the energy released at condensation comes exactly at the transition temperature you could use a second heat exchanger using room temperature air to do the final cooling to the dew point. There would certainly be a lot of details to work out that you have a lot more expertise about. But theoretically this seems like it could work well. This kind of arrangement wouldn't work in summer. You'd have to dry things outdoors then.

EDIT:
Actually you wouldn't need a second exchanger unless you wanted one just to optimize the different cooling phases. You could get by with just one exchanger if you used some automatic damper valves that controled the input and output of the cooling air. You could use some kind of dew point computer using temperature and humidity to divert the incoming and outgoing outside air to incoming and outgoing room air just above the dew point.