ASME EA-2G:2010 pdf free download – Guidance for ASME EA-2, Energy Assessment for Pumping Systems
1.1 Scope
This guidance document provides an application guide on how to utilize ASME EA-2, Energy Assessment for Pumping Systems. This guidance document pro- vides background and supporting information to assist in applying the Standard.
1.2 Purpose
ASME EA-2 does not provide guidance on how to perform a pumping system energy effciency assess- ment, but sets the requirements that must be performed during such an assessment. EA-2 was written in a form suitable for a standard, with concise text and without examples or explanations. This document was devel- oped to be used in conjunction with the standard to give basic guidance on how to fulfll the requirements of the standard. This document is only a guide and does not set any new requirements. ASME EA-2 can be used with or without this document.
2 introduction to PuMPinG SySteMS
2.1 overview
Pumping systems are used widely worldwide to pro- vide cooling and lubrication services, to transfer fuids for processing, and to provide the motive force in hydraulic systems. In fact, most manufacturing plants, commercial buildings, and municipalities rely on pumping systems for their daily operation. In the manufacturing sector, pumping systems represent 27% of the electricity used by industrial systems. In the commercial sector, pump- ing systems are used primarily in heating, ventilation, and air-conditioning (HVAC) systems to provide water for heat transfer and water pressure boosting of domes- tic potable water. Municipalities use pumping systems for water and wastewater transfer and treatment and for land drainage. Since pumping systems serve such diverse needs, they range in size from fractions of a horsepower to several thousand horsepower.
Pumping systems are essential to the daily operation of many facilities. This tends to promote the practice of oversizing pumps to ensure that the needs of the system will be met under all conditions. Intent on ensuring that the pumps are large enough to meet system needs, engi- neers who design pumping systems often overlook the cost of oversizing pumps and add more pump capac- ity than is necessary. Unfortunately, this practice results in higher-than-necessary system operating and main- tenance costs. In addition, oversized pumps typically require more frequent maintenance than properly sized pumps. Excess fow energy increases the wear and tear on system components, often resulting in valve damage, piping stress, and excess system operation noise. It is important to keep in mind that pumping systems are often parts of larger systems, such as complex indus- trial processes or HVAC systems. Therefore, potential impacts on the larger systems should be considered when evaluating pumping systems.
2.2.1 Pumps. Although pumps are available in a wide range of types, sizes, and materials, they can be broadly classifed into the two categories: positive dis- placement (PD) and centrifugal. These categories relate to the manner in which the pumps add energy to the working fuid. Positive displacement pumps move a set volume of liquid per revolution or stroke, and pressure is developed as the liquid is forced through the pump discharge into the system. Centrifugal pumps work by adding kinetic energy to a fuid using a spinning impel- ler. As the fuid slows in the discharge passage of the pump, the kinetic energy of the fuid is converted into pressure. Centrifugal pumps include axial (propeller), mixed-fow, and radial types.