A charge exchanger combines the advantages of both a traditional domestic hot water exchanger and a hot water vessel. The domestic hot water is contained in the vessel, which is charged with the domestic hot water that is produced in the heat exchanger. When the hot water demand is less than then charge exchanger flow, energy is stored by heating the water in the vessel.
When demand exceeds production, hot water is drawn from the vessel. The exchanger is often called a charging loop exchanger. If the domestic hot water system also contains circulation, then the system should be created using a heat exchanger with five connections.
The circulation pipe is connected directly to the heat exchanger. The system can be established with one or two pumps. The pump that circulates water between the heat exchanger and the vessel is called a charging loop pump.
If the system only contains one pump, then it serves as both the hot water circulator pump and the charging loop pump. Note that the pump is mounted on the supply side of the hot water loop.
A charging loop system is relatively complex to size and demands exact commissioning to function properly. A domestic hot water system with a charging loop is relatively more expensive than traditional solutions with either an exchanger or a tank.
Grundfos supplies a broad range of circulator pumps that meet requirements for charge exchangers in domestic heating and hot water applications.