Heat pumps are great, thank you Technology Connections for turning me on to them. If you don’t know, they can heat and cool in a very efficient manner. Powering a heat pump to heat a space vs an equal wattage electric heater (about three times more heat for the same power use!).
As you can see, the temp sensor labeled “RV Bedroom Temp” that is placed right above our heads, it’s not the most comfortable being blasted right on our faces and bodies with temps between 75-85F degrees all night in 15~ minute cycles.
Meet cardboard duct
Now air is being directed towards the front of the RV, with a bit into the bedroom. I can control how much goes into the bedroom vs front by controlling the horizontal vanes.
Temps now look like:
With “Outlet” being the temp coming right out of the heat pump. Front/bedroom temps are solid at 68F bedroom and 71F front, which is perfect! The electricity usage is also constant, instead of the compressor running in a “bang-bang” type fashion
I have some ideas to over-complicate this that involve 3D printing. I’ll print a shroud and I’m thinking about “assist” fans on each side which I can control the speed of to not only help draw the air through the air exchanger, but to also more directly guide the flow front vs bedroom.
The only shortcoming so far is that I need to set the thermostat higher than actual on the heat pump, more experimentation is required and you can still see the limiter being hit at full blast in the last chart between 120F-130F (with the thermostat at 88F/Max and fan on Turbo).
I bet forcing some more air through will increase the max heat output, especially as I’m restricting the flow with my shroud.
Ross Fisher 