What temperature does propane stop flowing?
Getting a tad nippy out, living here in the TT. Supposed to get down to minus 32C tonight. (about -25.6F) Cooking dinner just now, oven on baking some salmon, furnace trying to keep this thing w...
Forum Discussion
MEXICOWANDERER wrote:
LPG needs an appropriately large SURFACE AREA to vaporize liquid into gas. I installed a large hydronic heating system in a repair garage in the Sierra Nevada Mountains many years ago. A one million BTU boiler. At -25C it took four 500 gallon tanks set to offer enough surface area to gasify fuel for the boiler.
A vertical tank offers a poor relationship of surface area to gas storage. But nothing can be done about it except heat the tank. I've seen folks use an infrared LPG heater placed a meter distant from a big tank in an emergency.
yes. In fact most propane suppliers have graphs that will show the max BTU/hr that can be drawn from a tank at a given min ambient temperature when the tanks is at a low level, say 10% off initial capacity.
They use those graphs to determine the minimum size tank to supply an application taking into account the maximum draw. And why the bigger tanks are horizontal cylinders. But even with a horizontal cylinder, as you get near empty, the surface area is going down as well as you get near the bottom of the tank.
IIRC while a 7.5 gallon vertical tank is common for RV applications, it is actually undersized for a typical furnace draw below about 40F. And it gets worse when the furnace and HWH turn on.
I know my 7.5 gallon tank will switch over with about 1.5 gallons left if the HWH and furance come on in the morning with temps in the low 40's. I just wait till late in the morning and switch back to get the last gallon or so out of the tank.
