xv_721_scfm and xv_721_scfm_v2

For sites ARS14002, ARS16006, ARS19004, ARS20009 and ARS15002 xv_721_scfm_v2 is returned as base xv_721_scfm metric

xv_721_scfm metric.

• ARS15002 = 59.9 if XV_801A_OUT or XV_801B_OUT or XV_801C_OUT or XV_801D_OUT
• ARS15008 = sum(XV_801A_OUT, XV_801B_OUT, XV_801C_OUT, XV_801D_OUT) * 16.0
• ARS16006 = 26.5 if (XV_801A_OUT or XV_801B_OUT or XV_801C_OUT or XV_801D_OUT) and XV_721A_OUT and VFD_800A_FREQ_OUT == 0 and VFD_800B_FREQ_OUT == 0 and VFD_800C_FREQ_OUT == 0 and VFD_800D_FREQ_OUT == 0
• ARS13007 = 0.0 if XV_801A_OUT or XV_801B_OUT or XV_801C_OUT or XV_801D_OUT else NaN
• 0.04 * (pumpAFlow + pumpBFlow + pumpCFlow + pumpDFlow) if XV_721A_OUT else NaN

PumpFlow (A, B, C, D):

• ARS13007 = (10, 10, 10, 10)
• ARS15002 = (318, 318, 318, 318)
• ARS15008 = (70, 70, 70, 70)
• ARS14002 = (600, 600, 600, 600)
• ARS16005 = (1500, 1500)
• ARS16006 = (1200, 1200, 1200, 1200)
• ARS19004 = (1200, 1200, 600, 600)
• ARS20009 = (1200, 1200, 600, 600)

Version 2 of the xv_721_scfm metric.

This metric is calculated in 2 steps.

• Every day the model is created for xv_721 and xv_802 flow
• during metric calculation the output of the model is usd as metric value.

Model

This metric is based on precomputed flow based on 721 and 802 Tool.

The XV_721_SCFM_V2 calculation estimates the flow through the XV_721 valve using the values calculated using the XV_802 tool.

This calculation uses a combination of data filtering and mass balances to estimate the XV_721 flow. The primary principle of this tool is that all gas that enters TK_700 through either the XV_802 lines, or the XV_721 lines can only escape by being vented through the FCV_605 line. The flow through FCV_605 is already estimated using a Cv calculation according to FCV_605_SCFM. To estimate the XV_721 and XV_802 flows, FCV_605_SCFM flow data is filtered and averaged according to different scenarios:

1) Base Idle Use: no pumps are operational and system is idle. The only reason for FCV_605_SCFM flow is due to heat leak to TK_700 vaporizing the argon in it, also called argon boil off. 2) Flow is going though one or more pumps as defined by one or more XV_801 valves being open, and the Low-Pressure pump discharge line XV_721 is also open. This excess flow into TK_700 increases FCV_605 activity. 3) Flow is going though one or more pumps as defined by one or more XV_801 valves being open, and one or more High-Pressure pump discharge lines are also open, as defined by one or more XV_802 valves being open. Pumps are not pumping yet, and all VFD_FREQ_OUT tags = 0. This excess flow into TK_700 further increases FCV_605 activity. 4) Flow is going though one or more pumps as defined by one or more XV_801 valves being open, and one or more High-Pressure pump discharge lines are also open, as defined by one or more XV_802 valves being open. Pumps are pumping, and one or more VFD_FREQ_OUT tags > 0. This excess flow into TK_700 further increases FCV_605 activity

With each subsequent scenario the number of causes of increased FCV_605 activity goes up. Therefore the activity attributed to the flows from each cause/valve must be determined applying a mass balance to the filtered data.

The average FCV_605_SCFM flow rate is filtered according to the following filter criteria to isolate the data into the different flow scenarios detailed above. It is assumed that when more pumps are active there will be increased flow to TK_700, and therefore increased FCV_605_SCFM flow. Therefore, filtering is also applied dependent on the number of pumps active.

As an example, scenario 1 for argon boil off logs FCV_605_SCFM every time no XV_801 valves are open and averages the value for the time period selected. Scenario 2 logs FCV_605_SCFM every time 1 XV_801 is open (=1) and XV_721 is also open (=1). All filtering criteria are explained fully in the table.

Pump Recycle Filtered Table.xlsx

To back out the flows attributed to individual valves a mass balance approach is applied to the filtered data as follows:

Argon_Boil_off = FCV_605_SCFM if XV_801 == 0

XV_721_SCFM = (FCV_605_SCFM – Argon_Boil_off) if XV_801 == 1 and XV_721 == 1

These mass balances are applied to the averaged FCV_605_SCFM values filtered according to whether 1 or 2 pumps are running. If more than 2 pumps are running then the values calculated from the 2-pump active filtering and mass balances are used for XV_721_SCFM. This is because there is not enough time periods where 3 pumps run for there to be enough data points for the output to be statistically significant enough to perform this analysis.

It always takes the last computed value to estimate the flow

input

• XV_721_OUT
• XV_802A_OUT
• XV_802B_OUT
• XV_802C_OUT
• XV_802D_OUT
• XV_801A_OUT
• XV_801B_OUT
• XV_801C_OUT
• XV_801D_OUT
• VFD_800A_FREQ_OUT
• VFD_800B_FREQ_OUT
• VFD_800C_FREQ_OUT
• VFD_800D_FREQ_OUT
• FCV_605_SCFM
• 721 and 802 Tool

Metric calculation

This metric is based on precomputed flow based on 721 and 802 Tool. (Check previous section for model explanation)

It always takes the last computed value to estimate the flow

input

• XV_721_OUT
• 721 and 802 Tool

Site specific behavior

Sites ARS15002, ARS15008, ARS13007 don’t have XV_721_OUT sensors, so for them it is assumed that this valve is always open.