I wash my clothes, and when they get off the washer, its weight was increased by 3.35kg (amount of water to be evaporated to get dry clothes).
Now, I have two options:
Use an electric dryer. It takes 2 hours to dry the clothes, it's a 2700W dryer, so I used 5.4kWh.
Use a dryer rack. Then, water is evaporated by latent heat. I washed at 40°C, so the 3.35kg of water to be evaporated is probably at 35°C. Considering this formula, I need
2500-2,36*35+0,0016*35*35-0,00006*35*35*35, which is 2416kj/kg to evaporate the water, so, according to google converted, this is 0.617kWH/kg, so 2.07kWh.
I'm really surprised an electric dryer only consumes twice the energy needed to naturally evaporate the water. If my room heater works with fuel or gas, the 2.07kWh consumed to dry the clothes on the rack may end up emitting more carbon than the electric dryer would (if the electricity is produced cleanly).
This result really surprises me (I would have expected the electric dryer to consume at least 10 times more than natural evaporation). It makes me believe that I did something wrong in my computation...did I?