I was planning on installing a compact 110V water heater in my bus over the winter so as a temporary stop gap for the last couple months I just bought one of those 5 gallon solar shower bags and installed it in one of my skylights. Wow, not much water, but it warmed up fast and stayed warm for a while after sunset. (I'm not full-time boondocking, just weekends with generator)
Today, my inventor's imagination got fired up after seeing this on facebook:
I decided why not try the solar bag permanently as my daytime hot water supply. So I start planning the water lines and connections, took some time walking around the bus and it hit me.
Has anyone ever considered using the heated coils on the back of an RV fridge to heat fresh water? As with the above idea, why not repurpose the existing energy(heat) coming off the back of the fridge? I know this method will not be very efficient, but since the fridge will be running full-time (gotta keep the beer cold) and mine gets extremely cold, why can't I siphon off some of that energy thru a simple heat exchanger and heat the water to my sink ala point-of-use instant-on water heater?