# Formulas

##### FORMULAS FOR PIPE HEATING
1. Frost protection/heating of pipes. Pipes are covered with heating cable in order to compensate the heat losses through the thermal insulation and maintain a temperature over 0°C, maintain the required temperature.

Formulas

Heat loss calculation

Q = 2 x π  x Dt x k x 1,16 x s / In (dy / di)

 Q = The heat loss (W) Dt = The difference in temperature between the pipe and environment (°C) k = The permeability of the insulation material in W/m°C (Mineral wool = 0,045) dy = The outer diameter of the insulation (mm) di = The interior diameter of the insulation (mm) s = Safety factor (0 = indoors/1,5 = quay berth
1. Heating of pipes (unprogressive fluids). Pipes are covered with heating cable to rise the original temperature to a required temperature and to compensate heat losses through the thermal insulation.

Formulas

Calculation of required energy at heating of unprogressive fluids

P = Q + Ph

Ph = G x V x c x th / h

 P = Total required power for the required temperature rise (W) Q = Heat loss through the thermal insulation according to above (W) Ph = Required power to increase the temperature (W) G = Density (Kg/dm³) V = Volume dm³ (l) c = Heat permittivity  (Wh/Kg°C) th = Required temperature rise (°C) h = Required heating time
1. Heating of flowing fluids. Pipes are covered with heating cable to rise the temperature on a flowing fluid a number of degrees, while it passes the actual pipe length. At the same time the heat loss through the thermal insulation be compensated for.

Formulas

Calculation of energy requirement for heating of flowing fluids

P = Q + Phs

Phs = V x G x c x th