The Product Ratio Method An approach for determining circuit flow rates in domestic hot water circulation systems

Introduction Domestic hot water circulation systems compensate for heat loss from piping segments by facilitating continuous flow through a heat source to maintain water temperatures throughout the system.To ensure that piping segments receive flow proportional to the heat loss imposed on the system,a balancing valve is provided at each circuit for flow regulation(see Figure 1).A circulation system with properly balanced circuits regulates flow to maintain a uniform temperature al.each balancing valve.Proper balancing of domestic hot water circuits is often overlooked or substituted with approximate methods by designengineers and installers,leading to significant inaccuracies.