AT400362B - HEATER WITH A HEAT EXCHANGER INACTED BY A HEAT SOURCE - Google Patents

Description

AT 400 362 B

The invention relates to a heater with a heat exchanger acted upon by a heat source, which is connected to a heating circuit having a radiator, a flow and a return line and a circulation pump, a primary branch of a domestic water heat exchanger being switchable in parallel with the heating circuit via a changeover valve and a heating water tank is connected in 5 rows to the primary branch of the domestic water heat exchanger.

The heat requirement of single-family houses and apartments continues to decrease due to the modern construction with very effective thermal insulation. A heating system must therefore be adapted to the reduced heat requirement and designed for smaller nominal outputs in order to be able to operate with a high degree of efficiency. jo For domestic hot water preparation, on the other hand, the increased comfort requirements of the users require higher heat outputs and improved outlet conditions.

The combination devices of the type mentioned at the outset are increasingly difficult to meet the very different heating capacities for heating operation and for hot water preparation with increasing usage requirements and increasing comfort conditions. 75 In order to be able to meet the conflicting requirements, various solutions have been proposed, such as a high-performance circulation water heater with a large indirect store or with stratified storage tank, a directly heated domestic hot water tank with heating heat exchanger, a directly heated heating water tank with integrated hot water heat exchanger or - from the DE-OS 40 28 490 known - a downstream of a primary heat exchanger 20 heating water storage tank with integrated domestic water heat exchanger.

However, there are several disadvantages with these systems. For example, the first-mentioned system has the disadvantage of a large hot water heat exchanger surface, a large hot water tank being required.

In the case of a directly heated domestic hot water tank with a heating heat exchanger, there is the disadvantage of a heating flow temperature of 25, limited to approximately 60 ° C., at a high hot water temperature, which leads to rapid calcification of the tank. This system also requires a heater mixer.

With a directly heated heating water tank with hot water heat exchanger, there is the disadvantage of a constantly high heating water temperature, which makes a heating mixer necessary. 30 Furthermore, the heat content of the storage tank below 60 * C cannot be used and there is a noticeable drop in the hot water temperature when tapping, unless a correspondingly large storage tank is provided.

In the case of an indirectly heated heating water tank according to the above-mentioned DE-OS, the process water heat exchanger is hydraulically connected downstream of the heating water tank. As a result, an increase in the temperature in the primary branch of the domestic water heat exchanger is only possible indirectly, that is to say an increase in the temperature of the total amount of water in the heating water storage tank is greater than 35.

The aim of the invention is to avoid these disadvantages and to propose a heater of the type mentioned at the outset, which enables a high level of comfort when drawing off hot water, although its output is adapted to the heating requirements.

According to the invention, this is achieved in that the primary branch of the domestic water heat exchanger 40 is connected to the latter via a line opening into a lower region of the heating water reservoir and an open region in the flow direction of the heating water leads to the changeover valve.

These measures make it possible, on the one hand, to keep a supply of hot service water available through the heating water in the service water heat exchanger, which means that hot service water is immediately available at the start of tap 45, and on the other hand, through the heating water tank, which is connected downstream of the primary branch of the service water heat exchanger , also ensures that the cold process water can be supplied with more energy than the heat source provides, so that this can be dimensioned solely according to the needs of the heating circuit. This is possible because the stored, relatively hot, heating water can be fed to the primary heat exchanger of the heat source and further heated in this, whereby the hot water can be heated quickly via the hot water flow-through primary branch of the hot water heat exchanger, or a relatively large hot water throughput can be sufficiently heated .

Sufficient can be found with relatively small process water heat exchangers and heating water storage tanks, since in the arrangement according to the invention the heat content of the heating water storage tank and the heating output of the heating device can be fully used during a tap operation. In addition, only a heating water tank is required, which, in contrast to a domestic hot water tank, does not have to be protected against corrosion and can be designed for a much lower pressure, with no calcification problems to be expected. 2nd

AT 400 362 B

The process water is heated according to the flow principle, so that · significantly smaller heat transfer surfaces are required than in the process water storage tanks mentioned above. During the tapping process, the primary heat exchanger of the heat source increases the temperature of the stored heating water, so that a high flow temperature is applied to the process water heat exchanger even at lower storage temperatures.

In order to avoid mixing of the relatively cool water emerging from the hot water heat exchanger with the warm water in the heating water tank so that relatively long hot water can be supplied to the primary heat exchanger, one of the primary branch of the hot water heat exchanger can flow into the heating water tank opposite baffle plate be provided.

Furthermore, a temperature sensor can be arranged in the lowest area of the heating water tank, which is connected to a burner control, the heat source, for example a burner, being in operation at least as long and the flow through the primary branch of the hot water tank and the heating water tank being maintained until the whole Heating water tank is filled with hot heating water again.

According to a further feature of the invention, it can be provided that the process water heat exchanger is arranged in the heating water tank, the heating water tank surrounding a chamber receiving the heat source and the primary heat exchanger in a ring.

This results in a particularly compact structure of the heater.

The invention will now be explained in more detail with reference to the drawing.

Show:

Figures 1 to 3 schematically different embodiments of heating devices according to the invention.

In the embodiment according to FIG. 1, a burner 2, which acts on a primary heat exchanger 3, is arranged in a combustion chamber 1. A lower hood 4 is arranged above this primary heat exchanger 3, above which a flow safety device 5 and an exhaust gas hood 6, which leads to an exhaust pipe 7, are arranged.

The primary heat exchanger 3 is switched into a heating circuit which is formed by a flow line 8, a radiator arrangement (not shown) and a return line 9, as well as a changeover valve 10 arranged in this and a circulation pump 11.

In parallel to the radiator arrangement, a bypass circuit is provided, which is formed by a primary branch 12 of a domestic water heat exchanger 13 and a heating water tank 14 connected in series with the latter. This bypass circuit is connected directly to the flow line 8 and can be connected via the changeover valve 10 to the return line 9 instead of the radiator arrangement.

In the case of a tap of domestic water, a water switch 15 switches and gives a signal that leads to a start of the burner 2 and a switchover of the changeover valve 10 in such a way that a connection is established between the heating water tank 14 and the primary heat exchanger 3 and the heating circuit is interrupted.

Heating water flows from the uppermost areas of the heating water tank 14 to the changeover valve 10. This is ensured in that a line 16 is drawn up in the heating water tank 14 and is provided with an opening in the upper area or away from the inlet of the heating water tank 14. The line 17 coming from the service water heat exchanger 13 protrudes only slightly into the service water heat exchanger 13, a baffle plate 18 being arranged above the end of this line 17.

Furthermore, a temperature sensor 19 is arranged in the lower area of the heating water tank 14, which is connected to a control, not shown, of a solenoid valve 30 for the burner 2 and the changeover valve 10.

When the process water is drawn off, the warm water first located in a secondary branch 20 of the process water heat exchanger 13 flows out to a delivery valve 31. At the same time, the burner is started by the responsive water switch 15 and the bypass circuit is activated by the changeover valve 10. As a result, the circulation pump 11 draws approximately 65 * to 70 * C warm water from the heating water tank 14 and feeds it to the primary heat exchanger 3 of the heat source, which further heats it up. This water flows into the process water heat exchanger 13, or its primary branch 12. In the process water heat exchanger 13, this water is cooled to approx. 25 to 30 * C and the process water is heated to approx. 55 to 60 ºC.

This cooled heating water flows into the heating water storage 14, whereby the baffle plate 18 prevents the inflowing relatively cold water from mixing with the relatively hot water in the upper region of the heating water storage 14 and a stratification of the differently warm water masses is formed. 3rd

Claims (3)

AT 400 362 B This results in a largely constant outlet temperature over the entire tap cycle. The result of this is that approximately 2/3 of the power required for heating the process water is taken from the heating water tank 14 during the start of the peg and only approximately 1/3 of this power is introduced by the burner. The hot water tank 14 can be charged immediately after the tap operation. The heat source 2 remains activated and the circulation pump 11 continues to run until the heating water tank 14 is fully charged and has reached a sufficiently high temperature even in its lowest region. The embodiment according to FIG. 2 differs from that according to FIG. 1 in that the process water heat exchanger 13 is installed in the heating water tank 14. A pipe 21 is used in the process water heat exchanger 13 through which the inflowing heating water is deflected in accordance with the arrows 22 and thereby heats the process water located in the secondary branch 20 before it enters the heating water tank 14 in its lower region via the line 17. A baffle plate 18 is also built into this in order to force a stratification of the differently warm water masses. The embodiment according to FIG. 3 differs from that according to FIG. 2 in that the heating water reservoir 14 is designed in a ring shape and encloses a chamber 23 in which the combustion chamber 1 is arranged. The burner 2 is designed as a fall burner, which is supplied with a fuel gas / air mixture via a fan. The air flows into the chamber 23 through an opening 25 and is sucked in by the fan, which is simultaneously supplied with fuel gas via the gas line 26 in which the gas solenoid valve 30 is arranged. The bottom region of the chamber 23 is designed to slope away and is connected to a condensate drain 26, which leads to a siphon 27, an exhaust pipe 28 being arranged above the condensate drain 26, via which the exhaust gases are discharged. 1. Heater with a heat exchanger acted upon by a heat exchanger, which is switched into a heating circuit having a radiator, a flow and a return line and a circulation pump, a primary branch of a domestic hot water heat exchanger being switchable in parallel with the heating circuit via a switching valve and a heating water tank is connected in series to the primary branch of the domestic water heat exchanger, characterized in that the primary branch (12) of the domestic water heat exchanger (13) is connected to the latter via a line (17) opening into a lower region of the heating water reservoir (14) and one in Flow direction of the heating water upper area of the heating water tank (14) open line (16) leads to the changeover valve (10). 2. Heater according to claim 1, characterized in that the process water heat exchanger (13) is arranged in the heating water tank (14), the heating water tank (14) having a heat source (2) and the primary heat exchanger (3) together with a combustion chamber (1) receiving chamber (23) surrounds in a ring. Towards that 3 sheets of drawings 4