A Green Technology Challenge: Pressure reducing valve (PRV) is a valve that regulates the pressure, in our case, water or liquid fluid, from a higher pressure to a lower pressure. In other words, it is a devise to dissipate energy. For example, people living at the bottom of a hill usually experiences a higher than required water pressure. And in industries and large building complexes, some of the equipment, such as air conditioning units or chillers, do not require a higher pressure. In all cases typically, a PRV is installed upstream. It is this unnecessary pressure or energy that needs to be captured. How many cases are there that are presently using the PRV? There are hundreds of thousands of these PRVs presently used in the industries, federal facilities, commercial buildings and private homes. If some ambitious individual or company wishes to make $$, this is it. You may also get some federal grants, because of green technology. Example: A 4-inch pipe may have a nominal flow of 400 gallons per minute at an inlet pressure of 100 pisg. In most of the buildings, this pressure is too high and is reduced, by using a PRV valve, to 60 psig. The energy reduced at PRV valves are never recovered nor utilized for other purposes. For every 400 gallons per minute of water reduced from 100 psi to 60 psi pressure, 1. Pump brake horsepower = (400 gal/min x 40 lbs/sq in x 2.31 ft/lb) divided by 3960 x 80 % pump efficiency = 11.67 HP 2. Power lost = 11.67 HP x 0.745 KW/HP = 8.69 KW …