Discussion of Hydraulic Calculation Methods for Hot Water Heating Direct Return System

Abstract

For hot water heating direct return system, the common hydraulic calculation method in engineering design is constant temperature drop method,which is calculated from the farthest riser loop. Due to the limit of the minimum pipe size, the method is usually difficult to achieve the hydraulic balance for every riser loop, and it needs the utilization of valves to meet the need. In this paper, through a calculation example, it has explained that every riser loop is very easy to achieve hydraulic balance without the utilization of valves when the system is calculated from the nearest riser loop. Besides, the calculation order of this method has been given.