Averages

Time Weighted Averages

This calculates the average flowrates over a single time period using one of three methods.

The flow time and total method requires the cumulative total over the time period and uses the flow time to determine the average.

The other methods are for use where the flow is different but constant at two separate time intervals within the selected period. The average is calculated using the set 1 and set 2 flowrates with reference to either the total elapsed time or samples. The averages can be formatted as flow per day, per hour, per period A or per period B.

Sample Count Method


One of the following calculations are carried out for each flowrate depending on whether the flowrate is mass based, gross volume based, standard volume based or energy based.
TWA SampleCount

Symbol Description Units
Inc1 Increment for data set 1 -
Inc2 Increment for data set 2 -
Qv,1 Gross volume flowrate for data set 1 m3/s
Qv,2 Gross volume flowrate for data set 2 m3/s
Qs,1 Standard volume flowrate for data set 1 Sm3/s
Qs,2 Standard volume flowrate for data set 2 Sm3/s
Qm,1 Mass flowrate for data set 1 kg/s
Qm,2 Mass flowrate for data set 2 kg/s
Qe,1 Energy flowrate for data set 1
Qe,2 Energy flowrate for data set 2 MJ/s
qv,TWA Gross volume flowrate time-weighted average m3/s
qs,TWA Standard volume flowrate time-weighted average Sm3/s
qm,TWA Mass flowrate time-weighted average kg/s
qe,TWA Energy flowrate time-weighted average MJ/s

Flow Time and Total Method



One of the following calculations are carried out for each flowrate depending on whether the flowrate is mass based, gross volume based, standard volume based or energy based.
Gas_TWA

Symbol Description Units
qv,TWA Gross volume flowrate time-weighted average m3/h
qs,TWA Standard volume flowrate time-weighted average Sm3/h
qm,TWA Mass flowrate time-weighted average kg/h
qe,TWA Energy flowrate time-weighted average GJ/h
Qv Gross volume total m3
Qs Standard volume total Sm3
Qm Mass total kg
Qe Energy total GJ