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Massively trace forwards thermal-hydraulic regime for district heating network

Source: R/tracefw.R
tracefw.Rd

Trace values of thermal-hydraulic regime (temperature, pressure, flow rate, and other) in the bunched pipeline along the flow direction using user-provided values of specific heat loss power.

Usage

tracefw(
  sender = c(0, 1),
  acceptor = c(1, 2),
  temperature = c(70, NA_real_),
  pressure = c(pipenostics::mpa_kgf(6), NA_real_),
  flow_rate = c(20, NA_real_),
  d = rep_len(100, 2),
  len = rep_len(72.446, 2),
  loss = rep_len(78.4, 2),
  roughness = rep_len(0.001, 2),
  inlet = c(0.5, 1),
  outlet = c(1, 1),
  elev_tol = 0.1,
  method = "romeo",
  verbose = TRUE,
  csv = FALSE,
  file = "tracefw.csv",
  use_cluster = FALSE
)

Arguments

sender

identifier of the node which heat carrier flows out. Type: any type that can be painlessly coerced to character by as.character.

acceptor

identifier of the node which heat carrier flows in. According to topology of test bench considered this identifier should be unique for every row. Type: any type that can be painlessly coerced to character by as.character.

temperature

Sensor-measured temperature of heat carrier (water) sensor-measured on the root node, [°C]. Use NA_float_s for nodes without temperature sensor. Type: assert_double.

pressure

Sensor-measured absolute pressure of heat carrier (water) inside the pipe on the root node, [MPa]. Use NA_float_s for nodes without pressure sensor. Type: assert_double.

flow_rate

Sensor-measured amount of heat carrier (water) on root node that is transferred by pipe during a period, [ton/hour]. Type: assert_double. Use NA_float_s for nodes without flow rate sensor.

d

internal diameter of pipe (i.e.diameter of acceptor's incoming edge), [mm]. Type: assert_double.

len

pipe length (i.e. length of acceptor's incoming edge), [m]. Type: assert_double.

loss

user-provided value of specific heat loss power for each pipe in tracing path, [kcal/m/h]. Values of the argument can be obtained experimentally, or taken from regulatory documents. Type: assert_double.

roughness

roughness of internal wall of pipe (i.e. acceptor's incoming edge), [m]. Type: assert_double.

inlet

elevation of pipe inlet, [m]. Type: assert_double.

outlet

elevation of pipe outlet, [m]. Type: assert_double.

elev_tol

maximum allowed discrepancy between adjacent outlet and inlet elevations of two subsequent pipes in the traced path, [m]. Type: assert_number.

method

method of determining Darcy friction factor:

  • romeo

  • vatankhan

  • buzelli

Type: assert_choice. For more details see dropp.

verbose

logical indicator: should they watch tracing process on console? Type: assert_flag.

csv

logical indicator: should they incrementally dump results to csv- file while tracing? Type: assert_flag.

file

name of csv-file which they dump results to. Type: assert_character of length 1 that can be used safely to create a file and write to it.

use_cluster

utilize functionality of parallel processing on multi-core CPU. Type: assert_flag.

Value

data.frame containing results (detailed log) of tracing in

narrow format:

node

Tracing job. Identifier of the node which regime parameters is calculated for. Values in this vector are identical to those in argument acceptor. Type: assert_character.

tracing

Tracing job. Identifiers of nodes from which regime parameters are traced for the given node. Identifier sensor is used when values of regime parameters for the node are sensor readings. Type: assert_character.

backward

Tracing job. Identifier of tracing direction. It constantly equals to FALSE. Type: assert_logical.

aggregation

Tracing job. Identifier of the aggregation method associated with traced values. For forward tracing the only option is identity. Type: assert_character.

temperature

Traced thermal hydraulic regime. Traced temperature of heat carrier (water) that is associated with the node, [°C]. Type: assert_double.

pressure

Traced thermal hydraulic regime. Traced pressure of heat carrier (water) that is associated with the node, [MPa]. Type: assert_double.

flow_rate

Traced thermal hydraulic regime. Traced flow rate of heat carrier (water) that is associated with the node, [ton/hour]. Type: assert_double.

job

Tracing job. Value of tracing job counter. For forward tracing value of job counts the number of traced paths from root node. Type: assert_count.

Type: assert_data_frame.

Details

They consider the topology of district heating network represented by m325testbench:

Tracing starts from sensor-equipped root node and goes forward, i.e along the flow direction. Function traceline serves under the hood for tracing identified linear segments from root node to every terminal node. Hence they only need root node to be equipped with sensors. Sensors at other nodes are redundant in forward tracing, since the tracing algorithm by no means consider them for tracing.

Moreover in the forward tracing algorithm they assume the flow of heat carrier is distributed proportionally to the cross-sectional area of the outgoing pipeline. Actually, a lot of reasons may cause significant deviations from this assumption. As a result, the sequence of paired backward/forward tracing may be divergent for regime parameters.

Though some input arguments are natively vectorized their individual values all relate to common part of district heating network, i.e. associated with common object. It is due to isomorphism between vector representation and directed graph of this network. For more details of isomorphic topology description see m325testbench.

They are welcome to couple the algorithm with functionality of data.table.

See also

Other Regime tracing: m325tracebw(), m325tracefw(), m325traceline(), tracebw(), traceline()

Examples

library(pipenostics)

# Minimum two nodes should be in district heating network graph:
tracefw(verbose = FALSE)
#>   node tracing backward aggregation loss     flux        Q temperature
#> 1    1  sensor    FALSE    identity   NA       NA       NA    70.00000
#> 2    2       1    FALSE    identity 78.4 279.0696 136314.4    69.71603
#>    pressure flow_rate job
#> 1 0.5883990        20   0
#> 2 0.5813153        20   1

# Consider isomorphic representation of District Heating Network graph:
DHN <- pipenostics::m325testbench

# * remove irrelevant parameters from the test bench
DHN[c("year", "insulation", "laying", "beta", "exp5k")] <- NULL
DHN[c("temperature", "pressure", "flow_rate")] <- NA_real_

# * avoid using numeric identifiers for nodes:
DHN$sender   <- sprintf("N%02i", DHN$sender)
DHN$acceptor <- sprintf("N%02i", DHN$acceptor)

# * alter units:
DHN$d <- 1e3 * DHN$d  # convert [m] to [mm]

# * provide current regime parameters for root node
root_node <- 12
DHN[root_node, "temperature"] <-  70.4942576978  # [°C]
DHN[root_node, "pressure"]    <-   0.6135602014  # [MPa]
DHN[root_node, "flow_rate"]   <- 274.0           # [ton/hour]

# * provide actual values of specific heat loss power, [kcal/m/h], for each
# segment N01 - N26. Since N12 is a root node, the specific heat loss
# power for this acceptor is set to 0 (or may be any other numeric value).
actual_loss <- c(
  96.8,  96.8,  71.2, 116.7, 71.3,  96.8, 78.5, 116.7, 28.6, 24.5, 
 116.7,   0.0, 153.2,  96.8, 96.8, 116.7, 24.5, 116.7, 28.6, 96.8, 
  78.5, 116.7,  71.3,  96.8, 96.8,  71.1
)

# Trace the test bench forward for the first time:
fw_report <- do.call(
  "tracefw", c(as.list(DHN), list(loss = actual_loss), verbose = FALSE, elev_tol = .5)
)