DE4143026C2 - Low temperature central heating system - Google Patents

Description

The invention relates to a central heating system for heating of residential houses and / or commercially used houses, in the a heating medium, in particular water by means of a circulation pump removed from an oil or gas heated boiler and is led to radiators via a flow line, while the cooled heating medium via a return line from the radiators flows back and is fed back to the boiler above.

Such heating systems have to do justice to the growing environmental awareness become. This is done by installing low temperature boilers and reached by condensing boiler. In the condensing boiler the heat of condensation of the exhaust gases is still used fed.

In the low-temperature boiler, the exhaust gases should be up to be cooled to the dew point. Cooling below the dew point causes the formation of aggressive condensates, which Reduce the service life of the boiler or the boiler must run out corrosion-resistant material can be made, which is very expensive is. In addition, there is the problem of disposal condensate.

Central heating systems were initially only using a liquid orbit built by gravity. This circulation was due to the expansion of the warm water, the warm water due to the low specific gravity rises while the cooled water is returned to the boiler below. With the Powerful pumps became a forced circulation introduced by means of a circulation pump. But you noticed soon that in the boiler at low return temperatures unwanted condensate formed.

If the cold return water is fed to the bottom of the boiler, it has it strives to remain below. This will form cold zones in the bottom of the boiler, where condensate is preferred education begins. The main heat takes place during the heating phase transition but above instead while lower in range Temperature should take place.

Therefore, mixing valves have been installed to control the return temperature not to let it sink too much. Next to it are, for example known from DE-OS 29 06 869 and DE-OS 28 17 538 bypass lines, some of the warm water down the kettle again respectively.

It is also from CH-PS 109 667 a hot water heating system known for pump and gravity operation, in which at Pump operation opposite gravity operation directed flow of the heating medium is generated.

With this arrangement, the boiler can not as low  temperature boilers are operated because gravity the cold back-flowing heating medium drove the boiler downstairs cools down in such a way that, as is known, condensates below Form boiler. Opposite a boiler that heats up continuously, there is even increased condensate formation.

The purpose of CH-PS 109 667 is to use the lower rooms during the day Heating the building vigorously with the circulation pump; at night though only the upper rooms with gravity and without other additional regulation.

The invention has for its object conventional price valued boiler can be used as a low temperature boiler without that the disadvantages of condensation occur.

This object is achieved with a central heating system System of the type mentioned solved in that the central heating system is operated in the low temperature range and between the boiler and a check valve is provided for the radiators, that forces the heating medium to leave the bottom of the boiler and to flow through the flow line to the radiators and from there again by means of the return line in the heater flow back to avoid a flow that is caused by gravity.

The advantages of the invention can be seen in the fact that through the return cooled down returned to the boiler Water yourself

• 1. immediately mix with the hot water in the top of the boiler and this prevents the formation of cold zones in the boiler. Also if the return temperature the dew point even significantly falls below, no condensate can form in the boiler because there are no surfaces in the boiler on which the Would fall below the dew point.
• 2. The cooled water is in the heating phase above in the most effective area of the boiler because the hot ones Always aim for flames. Therefore there arises there improved heat transfer due to the low boiler temperature and the increased temperature difference. The exhaust gases are optimally used and the exhaust gas temperature can be reduced, which leads to improved efficiency.

According to a further embodiment of the invention, this is shown below heated heating medium taken from the boiler to the radiator fed from below and removed from the top of the radiator.

The discharge of the heated water down into a radiator has the advantage that, especially with high radiators Temperature difference between the top and bottom is not so large. The warm water flowing into the radiator at the bottom warms up the radiator below more intensely than already cooled water,  that descends from above. Such radiators heat particularly in close to the floor because of the higher temperature better.

According to a further advantageous embodiment of the invention it is provided that a delay relay or a thermostat switch when moving to room temperature Switch on the heating system with a delay.

Every boiler must be started up once. Will during cold water to the boiler during this start-up process led, the lower temperature range in which theoretically could form a condensate, drive through quickly. As soon as the operating temperature is reached, the Heating circuit can be switched on. With this additional device the night reduction can be carried out optimally down to room temperature conditions without affecting operational safety in any way would. This is the only way to achieve minimal energy losses at night.

An embodiment of the invention is in the drawing is shown and described in more detail below:

Fig. 1 shows a boiler 1 in which the heating medium water is heated. The heated water is removed from the boiler below through the flow line 2 and pumped by means of a circulation pump 3 , which is located in the heating water circuit, via a check valve 4 to at least one radiator 5 . There it gives off part of its heat and is returned through the return line 6 to the top of the boiler.

Claims (3)

1. Central heating system for heating residential houses and / or commercially used houses, in which a heating medium, in particular water, is removed at the bottom by means of a circulation pump ( 3 ) from an oil or gas-fired boiler ( 1 ) and is fed to radiators via a flow line ( 2 ) ( 5 ) is passed while the cooled heating medium flows back via a return line ( 6 ) from the radiators ( 5 ) and the boiler ( 1 ) is fed up again, characterized in that the central heating system is operated in the low temperature range and between the boiler ( 1 ) and a check valve ( 4 ) is provided for the radiators, which forces the heating medium to leave the boiler ( 1 ) at the bottom and flow through the flow line ( 2 ) to the radiators ( 5 ) and from there back into the system by means of the return line ( 6 ) flow back the boiler ( 1 ) to avoid a flow caused by gravity. 2. Central heating system according to claim 1, characterized in that the heated heating medium removed from the bottom of the boiler ( 1 ) is fed to the radiator ( 5 ) from below and is removed from the top of the radiator ( 5 ). 3. Central heating system according to claim 1 and 2, characterized in that a delay relay or a thermostat switch is provided in order to switch on the circulation pump ( 3 ) only after a delay when the heating system is at room temperature.