Pipe Junction SRG

Pipe junction functionality is provided in Source to allow modelling of pumping water from one place to another. It can be used to model pumped water supply and bidirectional flows between storage's.

Scale

Model operates at the site scale and at any time step Source is capable of using (e.g. daily).

Principal developer

eWater Solution

Version

Source version 4.5

Dependencies

At least two Pipe Junctions are required in the network to define connections.

Availability

Automatically installed with Source.

Rule based ordering

In a rule based ordering system, for each pipe junction relationship, the expected pump volume can be defined through a function which should take into account any possible losses, such as evaporation and other transmission losses from channels. It is assumed that there are no losses during the pump process. The amount of water pumped out equals the amount of water pumped in. No time delays apply in pipe junction, the water pumped out gets to its destination within the same model time step.  

The volume of water pumped in the flow phase is calculated through a function which is also used in the order phase and water user and constraint phase as the expected pump volume:

• Water User and Constraint Phase: the minimum and maximum constraints are affected by the expected pumping and whether it is incoming or outgoing,
• Order Phase: the orders will be affected (incoming water reduces water, outgoing water may generate an additional order),
• Flow Phase: moves the water in or out.

If the storage's upstream do not release enough water to meet the expected pump requirement, or there are losses between the storage and the pipe junction, then the actual water that arrives at the pipe junction is less than what has been requested, the pipe junction would still pump the requested volume. E.g. If the Pipe Junction requests 100ML, but only 80ML arrives, the Pipe Junction would still pump 100ML and the system will give an error indicating that there is a difference between the requested and pumped volumes. The losses used in the pump flow function should be reviewed to account for this discrepancy.

NetLP

In NetLP system, Source works out an optimal way to pass water requirements and release water to meet these requirements at the lowest cost, so the expected pump volume will always be the same as actual pump volume. For each pipe junction relationship, pump capacity and pump cost are the key factors that will affect flow direction in the whole system. Capacity determines the maximum pump capability a pipe junction can pump out for that pump direction. Cost defines pump cost per ML. It can be quite sensitive for a certain cost range compared to costs of other water supply options.

Key assumptions

Assumptions:

• In rule based ordering system, the volume of pumped water is assumed to be the same as expected pump volume even there is shortfall. So it is important to take all possible losses into consideration when defining the expected pump volume. 
• No loss and no time delay apply during pump process.

Input Data

Refer to the Source User Guide for detailed data requirements and formats.

Output Data

Outputs include the following results:

• Actual Flux: actual flow that has been pumped
• Actual Flux Volume: actual flow volume that has been pumped
• Expected Flux: expected flow that plan to pump
• Expected Flux Volume: expected flow volume that plan to pump
• Difference between expected and actual flux
• Difference between expected and actual flux volume
• Capacity: maximum pump capacity,only available with NetLP
• Cost: pump cost per ML, only available with NetLP 
• Flow Volume: actual pumped volume