Calculate values of heat flux emitted by underground pipeline segment which is not mounted in channel as a function of construction, operation, and technical condition specifications according to Appendix 5.1 of Minenergo Method 278.

This type of calculations is usually made on design stage of district heating network (where water is a heat carrier) and is closely related to building codes and regulations.

m278hlund(
t1 = 110,
t2 = 60,
t0 = 5,
insd1 = 0.1,
insd2 = insd1,
d1 = 0.25,
d2 = d1,
lambda1 = 0.09,
lambda2 = 0.07,
k1 = 1,
k2 = k1,
lambda0 = 1.74,
z = 2,
s = 0.55,
len = 1,
duration = 1
)

## Arguments

t1 temperature of heat carrier (water) inside the supplying pipe, [°C]. Type: assert_double. temperature of heat carrier (water) inside the returning pipe, [°C]. Type: assert_double. temperature of environment, [°C]. In case of underground laying this is the temperature of subsoil. Type: assert_double. thickness of the insulator which covers the supplying pipe, [m]. Type: assert_double. thickness of the insulator which covers the returning pipe, [m]. Type: assert_double. external diameter of supplying pipe, [m]. Type: assert_double. external diameter of returning pipe, [m]. Type: assert_double. thermal conductivity of insulator which covers the supplying pipe [W/m/°C]. Type: assert_double. thermal conductivity of insulator which covers the returning pipe [W/m/°C]. Type: assert_double. technical condition factor for insulator of supplying pipe, []. Type: assert_double. technical condition factor for insulator of returning pipe, []. Type: assert_double. thermal conductivity of environment, [W/m/°C]. In case of underground laying this is the thermal conductivity of subsoil. Type: assert_double. underground laying depth, [m]. Type: assert_double. distance between supplying and returning pipes, [m]. Type: assert_double. length of pipeline segment, [m]. Type: assert_double. duration of heat flux emittance, [hour]. Type: assert_double.

## Value

Heat flux emitted by pipeline segment during duration, [kcal]. If len of pipeline segment is 1 m and duration of heat flux emittance is set to 1 hour then the return value is equal to that in [kcal/m/h] units and so comparable with values of heat flux listed in Minenergo Order 325. Type: assert_double.

## Details

Details on using k1 and k2 are the same as for m278hlcha.