METHODOLOGY AND DESIGN OF HIGH-EFFICIENT WATER HEATER TANK WITH ADDITIONAL TANKLESS HEAT EXCHANGER FOR RESIDENTIAL / COMMERCIAL APPLICATIONS

摘要

This invention mainly consists of a water tank with an additional heatexchanger installed at the exit of the water outlet of the tank. This heatexchanger is located inside the central tube of the water tank so that itreceives heat from the same tank burner providing an additional surfacearea. This extra heat exchanger behaves as a tankless water heaterreceiving pre-heated water form the water tank. Therefore, the water fromthe tank receives additional energy as it crosses the additional heatexchanger. This idea incorporates the advantages of both tank and tanklesswater heaters and allows existing water tank owners to install a muchbetter water heating system that can provide both large amounts of hotwater initially followed by a endless limited supply of hot water, similar totankless systems. Another advantage of the system is that it increasesoverall efficiency of tank water heaters with the addition of extra heatexchanger surface. Additionally, it allows lowering the water heater tankaverage temperature, which reduces the heat losses associated with the hotwater stored in the tank for long periods of time. The system needs heatmodulation, but different than conventional tankless system that requireburner control, it can be simply obtained by mixing utility cold water withwarm water from the tank before entering the tankless part of the heater,keeping the outlet water temperature constant. The system providesendless supply of a fixed amount of water even when the water tanktemperature has dropped to a certain level. When the burner is operating itheats both the water inside the tank and the water that leaves the tank,already pre-heated and as mentioned above.