Low-pressure area most active tropical cyclone basin on Earth. Wind is initially accelerated from areas of high pressure to areas of low pressure. This is due to density (or temperature and moisture) differences between two air masses. Since stronger high-pressure systems contain cooler or drier air, the air mass is denser and flows towards areas that are warm or moist, which are in the vicinity of low-pressure areas in advance of their associated cold fronts. The stronger the pressure difference, or pressure gradient, between a high-pressure system and a low-pressure system, the stronger the wind. Thus, stronger areas of low pressure are
Pressure exchanger rates to the device. One application in which pressure exchangers are widely used is reverse osmosis (RO). In an RO system, pressure exchangers are used as energy recovery devices (ERDs). As illustrated, high-pressure concentrate from the membranes [C] is directed [3] to the ERD [D]. The ERD uses this high-pressure concentrate stream to pressurize the low-pressure seawater stream (stream [1] becomes stream [4]), which it then merges (with the aid of a circulation pump [B]) into the highest-pressure seawater stream created by the high-pressure pump [A]. This combined stream feeds the membranes [C]. The concentrate leaves the ERD at low