Process or Heating boiler for combined heating of a building heater and storage tank for drinking water

摘要

In order to increase the thermal efficiency of a three-pass boiler which is used for combined heating of a domestic hot water accumulator and a building heating system, it is proposed to surround the second and third pass with a first water space (5) having a comparatively low water volume. The first water space (5) is at least partly separated from a second water space (7) by a boundary surface (8). Whereas the heating of the water in the first water space (5) via heat-exchanger surfaces takes place directly by means of the hot waste gases, the second water space (7) is heated via the boundary surface (8) indirectly and by means of gravity circulation. The first water space serves solely to heat the accumulator, whereas the second water space has the connections for the heating-system circuit. The connection piece (9) for the flow of the accumulator circuit is situated at the highest point of the boiler and the return connection (10) at the lowest point of the first water space (5). At the same time, the water spaces (5, 7) are interconnected in this region, so that a normal gravity-flow operation of the boiler is possible. On the other hand, when a feed pump for the accumulator circuit is switched on, the gravity flow is cut off. IMAGE