Hydraulic Simulation Model for Close Loop Cooling water/Chilled water system

Cooling/Chilled Water Systems in industrial/Building facilities alike comprises a large fraction of total energy consumption of the facility. These systems therefore offer substantial energy savings potential.

A system approach rather than individual component study in isolation can be effective in assessing system performance of CW/CHW systems. Consequently it is important to assess system efficiency based on how well the end users are served by the pumps.

There are several steps involved in optimizing the configuration of a pumping system. These include determining the proper pipe size, designing a piping system lay-out that minimizes pressure drops and selecting low loss components. When a system needs to be modified or upgraded, the available pumping capacity should also be assessed.

It is in this context, piping network software has proved to be an effective tool in achieving optimization in CW/CHW SYSTEMS.  

About Software

The software performs extended period simulation of hydraulics within pressurized pipe networks.  A network consists of pipes, nodes (pipe junctions), pumps, valves and storage tanks or reservoirs.  The software tracks the flow of water in each pipe, the pressure at each node, the height of water in each tank throughout the network during a simulation period comprised of multiple time steps

The software contains a state-of-the-art hydraulic analysis engine that includes the following capabilities:

  • Places no limit on the size of network that can be analyzed.
  • Computes friction head loss using Hazen-Williams, Darcy-Weisbach, or Chezy-Manning equations.
  • Models constant or variable speed pumps
  • Models various types of valves including shutoff, check, pressure regulating, and flow control valves.
  • Allows storage tanks to have any shape (i.e., diameter can vary with height)
  • Considers multiple demand categories at nodes, each with its own pattern of time variation.

The hydraulic simulation model computes hydraulic heads at junctions and flow rates through links for a fixed set of reservoir levels, tank levels, and water demands over a succession of points in time. From one time step to the next reservoir levels and junction demands are updated according to their prescribed time patterns while tank levels are updated using the current flow solution. The solution for heads and flows at a particular point in time involves solving simultaneously the conservation of flow equation for each junction and the head loss relationship across each link in the network.

This process, known as hydraulically balancing the network, requires using an iterative technique to solve the nonlinear equations involved. The software employs the Gradient Algorithm for this purpose.

Below is a hydraulic network model snapshot captured for one of the sites of Reliance Industries Limited (RIL). While this closed loop network, as can be seen, comprises of primary and secondary circuits adding to the complexity for analysis, the hydraulic software renders easy and accurate analysis of various aspects of the operating parameters and system components viz. flow, pressure, velocity as well as network upgrade/modification needs.

Aditya Energy Services (AES) has successfully carried out such studies across different Industry sectors. List of the industries of repute studies are: Reliance Industries Limited (RIL – Vadodara, Hazira, Dahej facilities); Gujarat State Fertilizers Limited (GSFC, Vadodara); United Phosphorus Limited (UPL – Ankleshwar, Jhagadia, Vapi); ATUL Limited (Valsad); Asian paints Limited (APL – Ankleshwar, Kasna, Rohtak, Patancherru, Sriperumbudur & Hatauda, Nepal); Kansai Nerolac Paints Limited (KNPL – Jainpur, Hossur, Pune); Reliance Industries Limited (Textile Division, Naroda); JK Paper Mills Limited (JKPM – Rayagada, Odisha); ITC Limited (ITC – Bhadrachalam); Welspun India Limited (Vapi – Textiles); AYM Syntex Limited (Silvasa); Asian Paints Limited (Nepal); Pran Industries (Bangladesh); Dubia International Airport (Dubai) etc.