Which one is more accurate to use? and what is the heat loss coeficient since the defult value is 2.5 kJ/h.m2.K in Type 158 and 5 kJ/h.m2.K in type 534?
The heat loss coefficient depends on the type of tank and the insulation level. The model can handle both insulated and un-insulated tanks so it's up to the user to put in a representative value based on the tank that they will be studying.
In addition, in Type 534, what is the gas flue in the storage tank? Is it related to the gas flue from the boiler?
A gas flue is used in bottom-fired gas water heaters and provides an escape route through the tank for the products of combustion.
Jeff -- Jeff W. Thornton President Thermal Energy System Specialists LLC 3 N. Pinckney Street, Suite 202 Madison WI 53703 USA (608) 274-2577 www.tess-inc.com