Misunderstanding in hydraulic balance of HVAC systems

For hydraulic balance in a water system, usually applies balance valves, and adds regulative valve to follow varying load. Assumes that water velocity in the system falls in resistance squared area, and if the geometric parameters of resistance elements are determined, the integrated resistance coefficient is constant. Calculates varying condition performance of four systems. The results show that the system operation efficiency greatly decreases when adding balance valves and regulative valves, and the performance of the water system constituted with by system conception is superior to that of conventional water system.