Over the last few months, the ESI News Brief has been exploring the intricacies of pump system operation and optimization. We have covered the challenges faced when establishing a pump system improvement program, how to develop an Energy Cost Balance Sheet for each element, and how to work through the assessment process for a simple system. This month, for our final installment in this series, we will explore how to evaluate a system with multiple loads by breaking the system into circuits with various elements.
Figure 1 – Image of circuit with multiple circuits
In the system shown in Figure 1 there are three circuits: Circuit 1 consists of the tank (GS-TK-001), pump (GS-PU-001), heat exchanger (GS-HX-001), process element (GS-PE-001), control element (GS-FCV-002), the destination tank (GS-TK-001), and the interconnecting pipelines. Notice the supply tank (GS-TK-000), pump (GS-PU-001), and heat exchanger (GS-HX-001) are common elements of all three circuits.
Circuit 2 consists of the supply tank, pump, heat exchanger, GS-PE-02, GS-FCV-03, and the destination tank (GS-TK-002).
Earlier in this series we discussed that the total head produced by the pump element equals the head consumed by the process elements(static head, losses in pipelines, and process equipment) and control elements (the control valve). Another way of saying this is that the energy added to the fluid by the pump element equals the energy consumed by the process elements and control elements.