DE202005018362U1 - Exhaust system for exhaust of flue gases from heat generating devices e.g. boiler has integrated heat recycling system and water is led in annular gap between flue gas pipe and external pipe for absorption of heat of flue gases - Google Patents

Abstract

The exhaust system has an integrated heat recycling system. The water is guided in an annular gap between the flue gas pipe and the external pipe for absorption of the heat of the flue gases. The flue gas blower generates a predetermined pressure at the discharge of heat generating system by means of a pressure sensor and a frequency converter.

Description

The The invention described here serves to improve the efficiency of heat generation plants such as. shown in picture 0. The main application area is in buildings with a boiler plant or a cogeneration plant to generate heat for heating and Hot water.

existing Heat plants Some have exhaust gas temperatures of over 200 ° C. As the temperature level for the useful heat in the range Heating and hot water is only 30-70 ° C, there is a high potential for use for heat the exhaust.

Around can use this potential new plants with integrated additional heat exchangers are used. The other alternative is downstream external heat exchangers, thus the degree of utilization through heat recovery can be increased. External heat exchangers are already on Market available.

Of the The subject of this invention is an exhaust system for Nach equipment of heat generation plants, with exhaust gas heat as useful heat back can be won. The exhaust system with heat recovery can -as in picture 1 shown installed in an existing chimney or flue become. Alternatively, as shown in Figure 2, it can also be outside be installed.

The exhaust system with heat recovery is made up of pluggable exhaust pipe elements. An exhaust pipe element is shown in Figure 3. It consists of a socket end ( 1 ) in which during assembly the tail ( 2 ) of the next exhaust pipe element is introduced. The connection is sealed with the O-ring ( 3 ). The flue gas ( 4 ) flows through the exhaust pipe ( 5 ) from bottom to top. The exhaust pipe ( 5 ) is concentric in an outer tube ( 6 ) arranged. Through the annular gap located between the exhaust pipe and outer tube, the return water flows ( 7 ) of the heating system in countercurrent to the flue gas. The return water is in the riser ( 8th ) and in the end piece shown on Figure 4 at the deflection ( 9 ) passed into the annular gap.

The flue gas exiting at the end piece shown in Figure 4 cools in the exhaust pipe with heat recovery so far that it is only a few degrees above the temperature of the return water. Depending on the temperature of the return water, more or less strong condensation of the water content in the flue gas occurs in the exhaust pipe. The condensate is in the condensate collecting channel ( 10 ) and via the condensate drain ( 11 ) into the condensate collecting line ( 12 ) guided.

The connection between two exhaust pipe elements is shown in Figure 5. Due to the almost same temperature in the exhaust and in the outer tube-due to the significantly better heat transfer coefficient on the water side than on the exhaust side compensation of the linear expansion between exhaust and flue gas pipe is not required. The connections of the connections for the riser, the condensate line and the connections for the connection of the annular gaps ( 13 ) are carried out with fabric hose pieces and clamping or pressing clamps. The fabric hose pieces serve to accommodate expansion differences.

In order to avoid cooling and thus unnecessary heat loss at the outlet of the exhaust pipe, a closure flap (as shown in Figure 3) is at the end of the exhaust system ( 15 ) appropriate. The flap is opened by the flue gas flow and closed again by its own weight.

The double pipe and the condensate pipe are insulated in insulating foam ( 14 ) held firmly.

At consists of the connection points between the exhaust pipe elements the possibility of intermediate pieces like e.g. Sheets use, which also does not have straight exhaust paths with the modules and corresponding fasteners can be created. At the places where intermediate pieces be used for the Connection of the condensate and return water lines accordingly longer Used fabric hose pieces become.

The Exhaust technology integration takes place according to Fig. 1 or 1a. or picture z. In an integration according to Figure 2, the flue gas sucked by the fan from the existing flue gas pipe. At the Failure of the fan, the exhaust gases through the old flue directed.

With an integration according to picture 1 and 1a, the old flue 16 ) are used for receiving the heat exchanger. However, it is important that during operation of the heat generation plant exactly the amount of exhaust gas produced is absorbed. This is done with the aid of a variable speed blower ( 17 ), a frequency converter ( 18 ) and a pressure sensor ( 19 ). The pressure at the outlet of the heat generator is controlled by the flue gas blower ( 17 ) kept constant. The flue gas fan starts when the heat request to the boiler, ie before the ignition of the Bren and regulates the pressure at the flue gas outlet of the heat generator by varying the speed to the desired value. If the target pressure can not be maintained, the heat generation system goes to fault.

Simultaneously with the flue gas blower goes the return water circulation pump ( 20 ) and conveys the cold return water to the mouth of the exhaust system. From there it flows down in countercurrent to the flue gas and heats up or cools the flue gas. The warmed up water is then fed to the water room of the boiler.

The Not described here exhaust system with heat recovery as a heat exchanger, but at the same time as exhaust flue until it leaves the roof. Augrund the forced tour the flue gas becomes a much smaller cross-section for the exhaust flue needed as in an exhaust system with natural train. The resulting small footprint allows the Insert the exhaust pipe elements from above into the old flue. The Fixation in the old flue is done with spacers.

The Elements of the exhaust system with heat recovery are actually a series of heat exchangers. Every module has to be built vertically, so that the resulting calorific value Condensate can run down into the condensate collection channel.

at Exhaust gas temperatures of 160 ° C and 10 meters of usable exhaust train length, can save fuel between 10% and 20%.

For older boiler systems who work reliably, However, too high exhaust losses may be due to the installation the exhaust system described here with heat recovery a boiler replacement be avoided. As the boiler exchange often the exhaust system This must also be omitted.

Claims (7)

Exhaust system for the removal of flue gases from heat generation systems (eg boiler or CHP systems) with integrated heat recovery, characterized in that water to absorb the waste heat of the flue gas in an annular gap between the exhaust pipe (Figure 3, pos. 5 ) and outer tube (Fig. 3, Pos. 6 ) to be led. Exhaust system according to claim 1, characterized that the exhaust gas is conveyed through a flue gas blower, which by means of a pressure sensor and a frequency converter a desired Target pressure at the outlet of the heat generation plant generated. Exhaust system according to one of the preceding claims, characterized in that at the outlet of the exhaust pipe, a flap (Figure 4, Pos. 15 ) is attached to reduce the heat losses, which is opened by the flue gas flow and closed by its own weight. Exhaust system according to one of the preceding claims, characterized in that the exhaust system consists of plug-in exhaust pipe elements each element has the function of a stand-alone water / flue gas heat exchanger has. Exhaust system according to one of the preceding claims, characterized in that each element of the exhaust system a riser (Figure 3, pos. 8th ) for the water, in which this up to the deflection (Figure 4, Pos. 9 ), from where it is then passed in countercurrent to the flue gas. Exhaust system according to one of the preceding claims, characterized in that each element of the exhaust system, a channel for collecting the resulting condensate has. This channel is equipped with a condensate drain (Fig. 3, Pos. 11 ) connected to a condensate collector (Fig. 3, pos. 12 ) opens. The condensate is discharged through the manifold. Exhaust system according to one of the preceding claims, characterized in that each element of the exhaust system including the condensate collecting line (Figure 3, Pos. 12 ) and the riser (fig. 3 and fig. 4, pos. 8th ) to avoid heat loss in hard foam insulation (fig. 3 and fig. 4, pos. 14 ), which also serves to fix all foamed with the insulation parts.