DE202023106588U1 - Heating pipe for preheating a heat transfer medium - Google Patents

Abstract

Heating pipe (1) for preheating a heat transfer medium for central heating or for preheating drinking water, the heating pipe (1) having a line (2) for transporting the heat transfer medium or drinking water, a heating resistor (4) which is wound around the line (2). , a heat-insulating cover (3) which encloses the line (2) and the heating resistor (4), a first temperature sensor (6) for measuring a first temperature of the heating resistor (4) and a second temperature sensor (7) for measuring a second temperature of the Heating resistor (4), characterized in that the heating tube (1) has at least one further sensor device (8) which detects at least one value of an external variable, and the heating tube (1) has a phase control (9) for adjusting the thermal output of the heating resistor ( 4) and a control device (10) for regulating the phase control (9), the control device (10) being suitable and intended to control the phase control (9) taking into account the first temperature, the second temperature and the value of the external variable regulate.

Description

The invention relates to a heating pipe for preheating a heat transfer medium for central heating or for preheating drinking water. The heating pipe has a line for transporting the heat transfer medium or drinking water, as well as a heating resistor which is wound around the line. In addition, the heating pipe has a heat-insulating cover that encloses the line and the heating resistor. Two temperatures of the heating resistor are measured using two temperature sensors.

Central heating systems are predominantly used to heat buildings. Central heating systems are characterized by the fact that they have a single central heating point and supply several rooms or a building with the heat generated via a heat transfer medium. In hot water heating systems, heated water serves as a heat transfer medium. Common heating points are boilers or combination boilers. The latter are heating devices that are used both to heat the heating medium and to heat the drinking water.

The heated heat transfer medium is fed into the rooms or in the building and distributed via a pipe system, the so-called heating circuit. The heat transfer medium heated at the central heating point is passed from the heating point via a flow in the heating circuit to radiators or radiators in the building. These radiators or radiators serve as heat exchangers and release part of the thermal energy transported by the heat carrier into the surroundings of the rooms to be heated. The heat transfer medium is returned to the central heating point via the return of the heating circuit. The temperature of the heat transfer medium arriving at the heating point via the return is lower than the temperature of the heat transfer medium heated by the heating point and passed over the inlet. The temperature difference is usually around 5°C.

In order to ensure constant heating of the building, the declining heat transfer medium must be heated back up to the desired temperature for the inlet by the heating point. Heating the returning heat transfer medium requires more energy, the greater the temperature difference between the heat transfer medium in the flow and return flow.

It is therefore desirable to keep the aforementioned temperature difference as small as possible. A passive measure consists of thermal insulation of the heating system pipes wherever no heat transfer is desired. Ideally, however, this measure can only maintain the temperature of the heat transfer medium after it has passed through the radiators.

The object of the present invention is therefore to reduce the temperature difference between the heat transfer medium in the flow and the heat transfer medium in the return flow or between cold and hot water in the drinking water in an energy-efficient manner.

This task is solved by a heating pipe for preheating a heat transfer medium for central heating or cold drinking water. The heating pipe has a line for transporting the heat transfer medium or drinking water, a heating resistor which is wound around the line and a heat-insulating cover which encloses the line and the heating resistor. A first temperature of the heating resistor is measured using a first temperature sensor, and a second temperature of the heating resistor is measured using a second temperature sensor. The heating pipe also has at least one further sensor device, which detects a value of an external variable. Furthermore, a phase control for adjusting the thermal output of the heating resistor and a control device for regulating the phase control are provided. The control device is suitable and intended to regulate the phase control taking into account the first temperature, the second temperature and the value of the external variable.

The heating pipe is therefore intended to support central heating or for hot water preparation of drinking water.

The central heating is preferably a hot water heating system, so that the heat transfer medium is preferably water. However, other heat carriers, such as thermal oils, are also conceivable, so that other types of heating can also be considered as central heating.

Preferably, the line serves, on the one hand, to transport the heat transfer medium or drinking water through the heating pipe. The heat transfer medium or the drinking water flows into the line at a first end of the heating pipe, then flows through the line and out of the line again at a second end of the heating pipe. On the other hand, the line serves as a heat exchanger. To do this, the line absorbs the thermal energy of the heating resistor and transfers it to the heat transfer medium or the drinking water in order to heat the latter. The line is therefore advantageously a pipe or hose made of copper or aluminum. However, other materials, preferably metals, are also conceivable. The line is preferably a straight pipe. This has the advantage that the heating pipe can be easily inserted into the piping system of the heating circuit or into the drinking water pipe, with a piece of the piping system being replaced by the heating pipe. However, it is also conceivable that the line and thus the heating pipe has a pipe bend or turns.

The heating resistor is used to convert electrical energy into thermal energy. In a very simple embodiment, the heating resistor is a heating conductor, i.e. a metal wire. However, other embodiments of the heating resistor are also conceivable, such as tubular heating elements in which the heating resistor is coiled or corrugated or has a meandering shape. The thermal energy generated by the heating resistor is transferred to the line and from there to the heat transfer medium or to the drinking water.

Alternatively, in addition to the heating resistor, an induction heater for heating the conductor is also conceivable so that the conductor can transfer the thermal energy to the heat transfer medium. It is also conceivable that a bare wire heating element is used instead of the heating resistor. This is directly surrounded by the heat transfer medium in order to heat it up.

Therefore, the bare wire heating element is arranged within the line. However, other concepts for converting electrical energy into thermal energy are also conceivable.

The cable and the heating resistor are enclosed in a thermally insulating cover. For this purpose, the sleeve can be wrapped around the line and the heating resistor, foamed or attached in another advantageous manner. The casing reduces the release of thermal energy to the environment and thus ensures that the thermal energy generated by the heating resistor is mainly transferred to the pipe and thus to the heat transfer medium or the drinking water. For this purpose, the shell can consist of natural and/or artificial insulating materials. For example, the insulation material can be a foam based on polyurethane (PU foam). Preferably, the casing is highly fire-resistant or at least fire-retardant.

A first temperature sensor is provided for measuring a first temperature of the heating resistor. A second temperature sensor is provided for measuring a second temperature of the heating resistor. All suitable temperature sensors can be used for this. These can have, for example, NTC thermistors or preferably PTC thermistors. Preferably, the first temperature sensor and the second temperature sensor are attached to the outside of the heating resistor and are spaced apart from one another along the longitudinal axis of the heating tube. It is preferred that the first temperature sensor tends to be attached closer to the first end of the heating tube and the second temperature sensor tends to be attached closer to the second end of the heating tube. In this way, the temperature of the heating resistor can be monitored with the two temperature sensors. This serves to protect the heating resistor. The thermal output of the heating resistor is regulated based on the two values determined by the temperature sensors.

Another sensor device is used to detect at least one value of an external variable. This external variable is preferably characteristic of the power provided by a solar power system. The external variable is particularly preferably characteristic of an excess of power generated by a solar power system. The external variable can therefore preferably be used to draw conclusions about the power that a solar power system produces, and particularly preferably about the power that is produced by a solar power system or that which remains unused.

The external variable is preferably the brightness and in particular the brightness of daylight. For this purpose, the incidence of light is preferably measured. The incidence of light on the solar power system is preferably determined. However, it is also conceivable that the incidence of light is determined in an outdoor area or, for example, near a window.

It is also conceivable that the external quantity is an electric current. This electrical current is preferably the one which is fed into the public power grid as surplus from the solar power system. It is conceivable that the presence of an excess of electricity produced by the solar power system is recognized based on the external quantity.

The thermal output that is converted by the heating resistor is set via a phase control. The phase control does not have to be in direct contact with the remaining components of the heating pipe, but can also be attached externally and preferably connected to them and in particular to the control device and the heating resistor via cable. The phase control can also be embedded in the casing of the heating pipe tet be. The phase control is operated with alternating voltage, the amplitude of the input voltage preferably being in a range from 200 V to 250 V and preferably being 230 V. The effective voltage with which the heating resistor is operated is adjusted using pulse duration modulation. For this purpose, the current flow within the phase control is preferably controlled by a triac.

The phase control is regulated by a control device taking into account the first temperature, the second temperature and the value of the external variable. The control device does not have to be in direct contact with the remaining components of the heating pipe, but can be attached externally, preferably being connected via cable to the first and second temperature sensors and the further sensor device as well as the phase control. The control device can also be embedded in the casing of the heating pipe. It is also conceivable that the control device can communicate wirelessly, in particular with the further sensor device.

In a further embodiment, the further sensor device is a brightness switch. This allows the brightness of daylight to be determined as an external variable.

The brightness is preferably determined on the solar power system. It is also conceivable that the brightness is determined at another location outside or near a window. The brightness switch is used to activate the heating tube at a certain brightness. If this brightness is not present, the heating tube is deactivated. This is advantageous when a certain level of brightness is reached at which the solar power system more than covers the building's energy needs. It is conceivable that the heating pipe is activated and thus feeds the excess electrical energy in the form of thermal energy into the heating circuit or into the hot water system. In this way, the excess electrical energy produced by the solar power system can be used effectively. At the same time, it can be avoided that the heating tube is operated with electricity from the public power grid if the brightness is too low.

In a further embodiment, the sensor device is a current intensity sensor.

The current sensor preferably measures the electrical current that is fed into the public power grid. This electricity fed in results from a surplus of electrical power that is produced by the solar power system but is not consumed. It is conceivable that the electricity is measured at the point where it is to be fed into the public grid. The current strength in the cable is preferably determined galvanically isolated.

Electricity meters are also conceivable as current sensors, preferably electronic electricity meters and particularly preferably intelligent electricity meters. The latter can send and receive digital data, so it is conceivable that they can communicate wirelessly with the control device.

The advantage of the current sensor is that an effective excess of current can be detected and the heating pipe can be activated or deactivated accordingly.

In a further embodiment, the heating pipe is operated by a solar power system.

The heating pipe can thus advantageously be operated using an excess of electricity produced by the solar power system.

Preferably, the heating pipe can be operated via the in-house power network, via which the electricity from the solar power system is provided. This has the advantage that the heating pipe can be operated using the electricity produced by the solar power system without having to be connected directly to the solar power system.

In a further embodiment, the heating pipe has fastening devices at a first end and at a second end for inserting the heating pipe into the return of the central heating or into the hot water system.

The fastening devices are preferably common connecting elements installed in the piping system of a heating circuit or hot water system.

The heating pipe is preferably integrated into the heating circuit of the central heating, preferably in the return of the central heating, particularly preferably directly in front of the heating point. It is conceivable that an existing central heating system is expanded to include the heating pipe, i.e. converted. Part of the existing return is removed and replaced by the heating pipe. It is also conceivable that the heating pipe is installed when installing a new central heating system.

The heating pipe is preferably integrated into the hot water system, preferably in the inlet of the cold water into the hot water system, especially This is preferably in the cold water inlet directly in front of the water heater. It is conceivable that an existing hot water system is expanded to include the heating pipe, i.e. converted. Part of the existing cold water inlet is removed and replaced by the heating pipe. It is also conceivable that the heating pipe is installed when a new hot water system is installed.

In a further embodiment, the heating resistor at least partially encloses the line. The heating resistor surrounds the cable with several turns, with the heating resistor and the cable being in direct contact with one another.

Due to the direct contact between the cable and the heating resistor, the thermal energy is transferred from the heating resistor to the cable in the best possible way. In order to achieve the largest possible contact area and to provide the largest possible heating resistance, the heating resistance is wound around the cable as often as possible. The heating resistor preferably encloses the conductor in such a way that only a small area at the ends of the conductor is not covered by the heating resistor. There should preferably be sufficient space for the fastening device and/or the cover.

In a further embodiment, the heating resistor consists of a wire made of an alloy. The alloy is preferably the alloy with the brand name Konstantan.

The diameter of the constantan wire is preferably 0.5 mm.

The constantan alloy has the advantageous property that it has an almost constant specific electrical resistance over wide temperature ranges and is therefore well suited as a heating resistor.

However, other known heating conductor alloys, such as Kanthal, are also conceivable for the heating resistor.

In a further embodiment, the wire of the heating resistor has insulation made of perfluoroalkoxy polymers (PFA).

The diameter of the heating resistor therefore preferably has a diameter of 0.8 mm.

PFA have the advantageous property of being thermoplastically processable, so that the PFA insulation can be applied to the wire by extrusion. PFA are also high temperature resistant and flame retardant.

It is also conceivable that the insulation consists of polytetrafluoroethylene (PTFE) or other suitable insulators.

In a further embodiment, the heating tube is constructed radially in such a way that the line is arranged on the inside and the heating resistor is arranged outside the line and the two temperature sensors are in turn arranged on the outside of the heating resistor. In addition, the sleeve is arranged outside the line and at least partially outside the heating resistor as well as outside the two temperature sensors. The cover completely encloses the heating resistor and the two temperature sensors and at least partially encloses the cable. The cover has at least a first layer which is intended and intended for thermal insulation.

The phase control and the control device are preferably embedded in the casing and particularly preferably in the first layer of the casing.

The casing preferably has a second layer on the outside, which is intended and intended to protect the first layer or the heating tube from external influences such as moisture, chemicals or mechanical influences.

The casing and/or the line preferably have radial feedthroughs through which connections and cables for the heating resistor, the flow sensor, the temperature sensors, the safety temperature limiter, the phase control and/or the control device are guided.

In a further embodiment, the heating pipe has a flow sensor for measuring the flow of the heat transfer medium or drinking water through the line.

The flow sensor measures the flow of the heat transfer medium or drinking water transported through the pipe. Different types of flow sensors can be used, such as turbine wheel flow meters. In this way, it can be detected whether the heat transfer medium or drinking water flows through the heating pipe line. Depending on the measurement result of the flow sensor, the thermal output of the heating resistor can be regulated. It is conceivable that at least two states are provided for the heating wire. In this way, the heating wire can be deactivated in a first state be fourth and give off the full heat output in a second state. However, other states are also conceivable, whereby the thermal output can take on a value between 0% and 100% of the maximum thermal output depending on the flow.

In a further embodiment, the heating pipe has a safety temperature limiter (STB). The safety temperature limiter serves to interrupt the preheating by means of a heating tube when the STB detects a temperature preferably greater than 200°C, preferably greater than 180°C and particularly preferably greater than 150°C.

In this way, damage to the heating pipe itself, or the destruction of individual components of the heating pipe, or damage to the central heating system is avoided. The heating tube can preferably only be reactivated by manually switching on the STB.

It is also conceivable that the STB is preceded by a safety temperature monitor (STW) whose temperature threshold is below that of the STB. The heating pipe is also deactivated when the temperature threshold of the STW is exceeded, but is activated again when the temperature threshold of the STW is undershot.

The heating pipe therefore offers a way to feed excess energy from a solar power system into the heating circuit of a central heating system or into a hot water system. For this purpose, the heating pipe is integrated into the heating circuit of the central heating or hot water system. The two temperature sensors and the other sensor device determine specific values that are transmitted to the control device. Based on the transmitted values, the control device regulates the phase control, which accordingly sets the heating resistor or the thermal output of the heating resistor.

The working range of the heating tube is preferably at a temperature of the heating wire, measured at the first and/or second temperature sensor, between 28°C and 150°C. The heating tube is preferably deactivated at a temperature of the heating wire, measured at the first and/or second temperature sensor, of 110°C.

Further advantages, aims and properties of the present invention are explained with reference to the following description of the accompanying figures. Similar components can have the same reference numerals in the different embodiments.

• 1 eine perspektivische Darstellung des Heizrohrs mit Teilschnitt
• 2 eine schematische Darstellung einer Ausführungsform des Heizrohrs

Show in the figures:

• 1 a perspective view of the heating pipe with a partial section
• 2 a schematic representation of an embodiment of the heating pipe

In the 1 an embodiment of the heating pipe 1 is shown with a partial section. In this embodiment, the heating tube 1 extends along the axis A. The heating tube has a line 2, which also extends along the axis A. The line 2 is designed as a tube which has a circular cross section. In this embodiment, the longitudinal axis of the line 2 is congruent with the axis A. The line 2 has a first end 11 along the longitudinal axis on one side and a second end 12 on the opposite side of the line.

The line 2 has an opening at the first end 11 and at the second end 12. Through these openings, for example, a heat transfer medium can flow into the line at the first end 11 and flow out of the conductor at the second end 12. The direction of flow within the conductor 2 is predominantly in the direction 16, this direction 16 running parallel to the axis A.

Viewed radially, the heating resistor 4 is arranged outside the line 2, the heating resistor 4 being in contact with the line 2 and being wound around it with a large number of turns. The heating resistor 4 thus extends in the direction of the axis A over an area B1 of the line 2, the area B1 not extending to the ends 11 and 12.

Viewed radially, a casing 3 is also arranged outside the line 2. The casing 3 extends in the direction of the axis A over an area B2, the area B2 being larger than the area B1. In addition, viewed radially, the sleeve 3 is also arranged outside the heating resistor 4 in the area B1, the sleeve 3 being in contact with the heating resistor 4 within the area B1. Outside the area B2, the casing 3 is in contact with the line 2.

The cover 3 has a first layer 14 and a second layer 15. The second layer 15 forms the outside of the casing 3, so that the second layer 15 forms the two end faces and the outer surface of the casing 3. Inside the casing 3, i.e. enclosed by the second layer 15 with respect to the end faces and the outer lateral surface, is the first layer 14. The inner lateral surface of the casing 3 forms the first layer 14.

2 shows a schematic representation of a further embodiment of the in 1 shown heating pipe 1, a schematic being Ten view of the heating pipe 1 is shown. Similar components are identified with the same reference numbers.

The longitudinal axes of the line 2 and the casing 3 continue to coincide with the axis A. The heating resistor 4 is wound around the line 2 with several turns.

Fastening devices 13 are provided around the line 2 at the first end 11 and at the second end 12. These fastening devices 13 protrude beyond the line 2 at the second end 12 along the axis A and in the direction 16, and at the first end 11 along the axis A and in the opposite direction to the direction 16. The fastening devices 13 are flush with the casing 3 at the second end 12 along the axis A and in the opposite direction 16, and at the first end 11 along the axis A and in the direction 16, so that the fastening devices 13 lie outside the area B2. The cover 3 and the fastening devices 13 touch each other with the end faces.

The heating pipe 1 has a first temperature sensor 6 and a second temperature sensor 7 inside the line 2, the temperature sensors 6 and 7 being spaced apart from one another and the first temperature sensor 6 preferably being located at the first end 11 and the second temperature sensor 7 preferably being located at the second end 12 located. The first temperature sensor 6 and the second temperature sensor 7 are each outside the area B1 and within the area B2. The two temperature sensors 6 and 7 are each connected to the control device 10 via separate cables. The cables run out of the line 2 and through the casing 3 in the radial direction.

The flow sensor 5 is arranged inside the line 2. This is connected to the control device 10 via a cable. The cable runs out of the line 2 and through the sheath 3 in the radial direction.

The control device 10 is located decentrally to the line 2, the casing 3 and the heating resistor 4. The control device 10 is therefore arranged externally to these components of the heating tube 1. The control device 10 is each connected by a cable to the temperature sensor 6, the temperature sensor 7, the flow sensor 5 and the further sensor device 8, and receives data from these components. In addition, the control device 10 is connected to the phase control 9 via a cable.

The phase control 9 is located decentrally to the line 2, the casing 3 and the heating resistor 4. The phase control 9 is therefore arranged externally to these components of the heating tube 1. The phase control 9 is connected to the control device 10 via a cable and to the heating resistor 4 via another cable.

The further sensor device 8 is located decentrally to the line 2, the casing 3 and the heating resistor 4. The sensor device 8 is therefore arranged externally to these components of the heating tube 1. In this embodiment, the sensor device 8 is connected to the control device by a cable.

The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided that they, individually or in combination, are new compared to the prior art. It should also be noted that the individual figures also describe features that can be advantageous in themselves. The person skilled in the art immediately recognizes that a specific feature described in a figure can be advantageous even without adopting further features from this figure. Furthermore, the person skilled in the art will recognize that advantages can also arise from a combination of several features shown in individual or different figures.

Reference symbol list

1

heating pipe

2

Line

3

Covering

4

Heating resistance

5

Flow sensor

6

First temperature sensor

7

Second temperature sensor

8th

Further sensor device

9

Phase control

10

Control device

11

First end of the heating pipe

12

Second end of the heating tube

13

Fastening device

14

first layer / insulation material

15

second layer

16

Flow direction of the heat transfer medium

A

Longitudinal axis of the heating tube

B1

first area

B2

second area

Claims (11)

Heating pipe (1) for preheating a heat transfer medium for central heating or for preheating drinking water, the heating pipe (1) having a line (2) for transporting the heat transfer medium or drinking water, a heating resistor (4) which is wound around the line (2). , a heat-insulating cover (3) which encloses the line (2) and the heating resistor (4), a first temperature sensor (6) for measuring a first temperature of the heating resistor (4) and a second temperature sensor (7) for measuring a second temperature of the heating resistor (4), characterized in that the heating tube (1) has at least one further sensor device (8) which detects at least one value of an external variable, and the heating tube (1) has a phase control (9) for adjusting the thermal output of the Heating resistor (4) and a control device (10) for regulating the phase control (9), the control device (10) being suitable and intended to control the phase control (9) taking into account the first temperature, the second temperature and the value of the external to regulate size. heating pipe (1). Claim 1 , characterized in that the further sensor device (8) is a brightness switch with which the brightness of daylight can be determined as an external variable. heating pipe (1). Claim 1 , characterized in that the further sensor device (8) is a current sensor. Heating pipe (1) according to one of the preceding claims, characterized in that the heating pipe (1) is operated by a solar power system. Heating pipe (1) according to one of the preceding claims, characterized in that the heating pipe (1) has fastening devices (13) at a first end (6) and at a second end (7) for inserting the heating pipe (1) into the return of the central heating or into the hot water system. Heating pipe (1) according to one of the preceding claims, characterized in that the heating resistor (4) at least partially encloses the line (2), the heating resistor (4) enclosing the line (2) with several turns and the heating resistor (4) and the line (2) is in direct contact with each other. Heating tube (1) according to one of the preceding claims, characterized in that the heating resistor (4) consists of a constantan wire. Heating pipe (1) according to the previous claim, characterized in that the constantan wire has insulation made of extruded PFA. Heating pipe (1) according to one of the preceding claims, characterized in that the heating pipe (1) is constructed radially in such a way that the line (2) is arranged inside and the heating resistor (4) is arranged outside the line (2) and the first and second temperature sensors (6, 7) are arranged on the outside of the heating resistor (4), and that the casing (3) is both outside the line (2) and at least partially outside the heating resistor (4) and the first and second temperature sensors (6, 7) is arranged, wherein the casing (3) completely encloses the heating resistor (4) and the first and second temperature sensors (6, 7) and the line (2) at least partially, the casing having at least a first layer (14), which is intended and intended for thermal insulation. Heating pipe (1) according to one of the preceding claims, characterized in that the heating pipe (1) has a flow sensor (5) for measuring the flow of the heat transfer medium or drinking water through the line (2). Heating pipe (1) according to one of the preceding claims, characterized in that the heating pipe (1) has a safety temperature limiter, the safety temperature limiter being used to interrupt the preheating by means of the heating pipe (1) at a first and/or second temperature of preferably greater than 200°C, preferably greater than 180°C and particularly preferably greater than 150°C.

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