630.941.7600 | [email protected] | valmatic.com 141 4/24 An important characteristic of valves in water pumping systems that is often overlooked is the valve’s ability to minimize energy consumption. Common flow coefficients for various valves used in pumping systems are shown below. Since Cv represents the flow through a valve with a 1 psi pressure drop, we can see that a Ball Valve provides the lowest headloss characteristics. The headloss from valves can be converted into the energy cost related to the pumping electrical power needed to overcome the additional headloss from the valve with the equation: A = (1.65 Q rH Sg C U) / E Where: A = annual energy cost, dollars per year Q = flow rate, gpm rH = head loss, ft. of water Sg = specific gravity, dimensionless C = cost of electricity, $/kW·h U = usage, percent E = efficiency of pump/motor set The table shows that the Val-Matic Ener•G® AWWA Ball Valve with its low energy cost pays for itself over its life. It consumes less than 1% the energy of a Globe-Style Control Valve. Larger systems and systems operating at higher velocities will provide even greater savings. If your goal is to design a “Green” pumping system, the Val-Matic Ener•G® Ball Valve is the valve of choice. 100 90 80 70 60 50 40 30 20 10 0 10 20 30 40 50 60 70 80 90 100 Valve Position, Percent Open Valve Inherent Flow Characteristics Globe Butterfy Ball Valve Cv, Percent of Max. Equal Percentage Quick Opening (Gate) Plug In addition to being the best selection for energy savings, the Val-Matic Ener•G® Ball Valve is the best selection for surge control. Its inherent flow characteristics are highly suited to control flow and pressure. Some valves like Globe and Plug will linearly reduce the flow rate in proportion to the movement of the closure member. Quick Opening valves, such as Gate Valves, only affect the flow during the last 30% of their closure. Equal percentage valves, like the Ball Valve, uniformly change the flow rate during the full travel. The graph below provides the Inherent Flow Characteristics of various types of valves. The data is expressed in terms of flow coefficient (Cv) at various percents of the valve’s position. The most desirable flow characteristic for surge control is equal percentage as provided by the Val-Matic Ener•G® Ball Valve. * Assumes 50% usage over 40 years, $.08/kw-hr, 12 ft/sec velocity, 0.8 efficiency 12 in. Valve Flow Data Type of Valve Cv rH 40-Year Energy Cost* Swing Check & Weight 3,395 3.58 $49,900 Globe-Style Control Valve 1,800 12.75 $177,800 Butterfly Valve 6,550 0.96 $13,400 Eccentric Plug Valve 4,750 1.81 $25,300 Ener•G® AWWA Ball Valve 22,800 0.07 $936 Inherent Flow Characteristics Ener•G® Ball Valves Ener•G® Ball Valves Energy Cost Savings Flow Characteristics
