Calculate normative heat loss of the supplying pipe mounted in underground 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.

## Usage

m278hlcha(
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,
b = 0.5,
h = 0.5,
len = 1,
duration = 1
)

## Arguments

t1

temperature of heat carrier (water) inside the supplying pipe, [°C]. Type: assert_double.

t2

temperature of heat carrier (water) inside the returning pipe, [°C]. Type: assert_double.

t0

temperature of environment, [°C]. In case of channel laying this is the temperature of subsoil. Type: assert_double.

insd1

thickness of the insulator which covers the supplying pipe, [m]. Type: assert_double.

insd2

thickness of the insulator which covers the returning pipe, [m]. Type: assert_double.

d1

outside diameter of supplying pipe, [m]. Type: assert_double.

d2

outside diameter of returning pipe, [m]. Type: assert_double.

lambda1

thermal conductivity of insulator which covers the supplying pipe [W/m/°C]. Type: assert_double.

lambda2

thermal conductivity of insulator which covers the returning pipe [W/m/°C]. Type: assert_double.

k1

technical condition factor for insulator of supplying pipe, []. Type: assert_double.

k2

technical condition factor for insulator of returning pipe, []. Type: assert_double.

lambda0

thermal conductivity of environment, [W/m/°C]. In case of channel laying this is the thermal conductivity of subsoil. Type: assert_double.

z

channel laying depth, [m]. Type: assert_double.

b

channel width, [m]. Type: assert_double.

h

channel height, [m]. Type: assert_double.

len

length of supplying pipe, [m]. Type: assert_double.

duration

duration of heat loss, [hour]. Type: assert_double.

## Value

Normative heat loss of supplying cylindrical pipe mounted in channel during duration, [kcal]. If len of pipe is 1 m (meter) as well as duration is set to 1 h (hour) (default values) then the return value is also the

specific heat loss power, [kcal/m/h] and so comparable with those prescribed by Minenergo Order 325. Type: assert_double.

## Details

k1 and k2 factor values equal to 1 mean the best technical condition of insulation of appropriate pipes, whereas for poor technical state factor values tends to 5 or more.

Nevertheless, when k1 and k2 both equal to 1 the calculated specific heat loss power [kcal/m/h] is sometimes higher than that listed in Minenergo Order 325. One should consider that situation when choosing method for heat loss calculations.

Other Minenergo: m278hlair(), m278hlund(), m278insdata, m278inshcm(), m278soildata, m325beta(), m325nhl(), m325nhldata, m325testbench

## Examples

 library(pipenostics)

m278hlcha()
#> [1] 86.92977
#

## Naive way to find out technical state (factors k1 and k2) for pipe
## segments constructed in 1980:
optim(
par = c(1.5, 1.5),
fn = function(x) {
# functional to optimize
abs(
m278hlcha(k1 = x[1], k2 = x[2]) -
m325nhl(year = 1980, laying = "channel", d = 250, temperature = 110)
)
},
method = "L-BFGS-B",
lower = 1.01, upper = 4.4
)\$par
#> [1] 4.285442 4.323628
# [1] 4.285442 4.323628