Can waterheater be laid on its side
I have a new rheem heat pump water heater that I will be installing to replace my Geospring that I have given up on. Been experimenting with 300 watt 24 volt dc element powered of my battery. 24/7. I t will make more hot water than I need so have to shut off the power some. I want to take the old 50 gal Geospring down in my celler crawl space which has block walls and cement floor. Just like a basement but only has 42 inch clearance under floor beams. I want to lay it on its side and connect the dc element to preheat the water some before it goes to my new waterheater in my ground floor utility room. I am going to use an unused solar panel to power The dc element. I know it will not overheat the water because it will only heat when the solar panel is working. A survey I read states that the well water temp. is 44 degree F. I have 2 175 watt solar panels that I can use and if 2 would make too much power I could also connect the 240 volt 4500 watt panel which only uses about 55 to 60 watts of 24 vdc. . I also bought 9 new panels to power my magnum inverter. Thinking of putting a 24 volt temperature guage in my power room to monitor the dc powered water tank. WHAT IS YOUR OPINION?