DE20014742U1 - Condensing heat exchanger for low and low temperature boilers - Google Patents

Description

Combustion heat exchangers for cryogenic and low-temperature boilers

The invention relates to a condensing heat exchanger for cryogenic and low-temperature boilers with an additional forced draught burner.

The previously known low- and/or low-temperature boilers operate according to the principle of taking the combustion air from the immediate environment.

In addition to the deterioration of the indoor climate over a defined period of time, the main disadvantage of such systems is that the utilisation of the calorific value or partial utilisation of the fuels is too low.

It is therefore necessary to overcome these disadvantages inherent in the state of the art.

It is therefore the object of the invention to propose a solution which, through simple and efficient technical measures, enables the new equipment as well as the conversion of existing low- and low-temperature boilers in such a way that outside air can be used from now on, while at the same time the use of condensing or low-condensing technology is raised to a higher level in order to improve the environmental balance.

According to the invention, the object is achieved as follows, with reference to claim 1 for the basic inventive idea. The further development of the invention results from claims 2 to 3.

Further explanations of the inventive solution will follow.

In an exhaust gas heat exchanger downstream of the burner and boiler, there is a heat exchanger connected to the flow and return lines as well as an air preheater, which on the one hand

• · ·Lt · «

-2-

&ngr;&ogr;&eegr; sucked in outside air and on the other hand can be affected by combustion exhaust gases. The cooled and excess burner exhaust gases find their way outside via the chimney connection located at the upper end of the exhaust gas heat exchanger.

The burner exhaust gases flowing parallel to the pipes of the air preheater and directly onto the heat exchanger not only contribute to the desired positive warming of the outside air taken in, but also raise the level of the return temperature.

The preheated outside air is fed into the burner chamber by means of a nozzle attached to the exhaust gas heat exchanger and a subsequent line, whereby an existing burner fan in combination with an additional fan is arranged in front of the burner chamber.

It can be provided that the amount of preheated outside air can also be used in part for direct interior heating via a branch using an additional fan that can be switched on. In this case, the supply line of the heated air that leads to the burner is divided in its capacity.

The control system for the burner and boiler is equipped with a return temperature limiter to prevent the temperature from falling below the dew point. If necessary, a second burner stage can be controlled via the outside temperature.

The invention will be explained in more detail below using an exemplary embodiment.
The following figures will be used.

Figure 1: Heating system with condensing heat exchanger - principle diagram

Figure 2: Exhaust gas heat exchanger in the condensing heat exchanger - sectional view

-3-

The reference symbols used in detail have the following meaning:

1 - Burner

2 - Boiler

3 - Air preheater

4 - Heat exchanger

5 - Heating flow

6 - Heating return \

7 - Burner exhaust gases (inlet)

8 - Burner exhaust gases (outlet)

9 - Line to burner

10 - Fresh air intake

11 - Fresh air

12 - Condensate nozzle towards condensate vessel

13 - Chimney

The burner 1 is directly connected to the compact condensing heat exchanger by means of the line to the burner 9. The hot burner exhaust gases enter the condensing heat exchanger via the inlet 7 and leave the unit of heat exchanger 4 and air preheater 3 via the outlet 8 for burner exhaust gases in the direction of the chimney 13. The double use of the hot burner exhaust gases after their supply via the inlet 7 by the application of the heat exchanger 4 and then the air preheater 3 consisting of parallel pipes has the particular advantage that the level of the return temperature of the heating return 6 increases and thus less heating energy has to be applied in a controlled manner.

-A-

Boiler 2 supplies the connected consumers, if necessary with a circulation pump - not shown here, via heating circuit 5. The circulation of the air turnover for burner 1 is supported in the known manner with a burner fan. It can be particularly advantageous if, if there is sufficient capacity, part of the preheated air is used at the same time for direct room heating.

In this case, an additional fan and a branch on the line to burner 9 can be added structurally.

A condensate nozzle in the direction of a condensate vessel 12, if present, serves to drain the condensate that has precipitated.

The condensing heat exchanger can be used universally for installation in new systems as well as for retrofitting existing old systems.

Claims (3)

1. Condensing heat exchanger for deep and low temperature boilers, characterized in that a combination consisting of the heat exchanger ( 4 ) and the air preheater ( 3 ) is arranged in the sucked in flow of fresh air ( 11 ), with an inlet ( 7 ) for hot burner exhaust gases in the upper part and, opposite, the outlet ( 8 ) for the cooled burner exhaust gases in the direction of the chimney ( 13 ) being provided and the heated fresh air, which is guided through parallel pipes of the air preheater ( 3 ), can be discharged via the line to the burner ( 9 ) by means of a burner fan. 2. Condensing heat exchanger according to claim 1, characterized in that a branch for direct room heating can be provided at the beginning of the line to the burner ( 9 ), an additional fan being connected to this circuit. 3. Condensing heat exchanger according to claim 1 and 2, characterized in that the combination of air preheater ( 3 ) and heat exchanger ( 4 ) designed as a structural unit is designed both for new systems and as a retrofit kit for systems already in operation.