WO2007113613A1 - Tankless water heater - Google Patents

Abstract

The invention relates to a tankless water heater, both for supplying a house with hot domestic water via the use of electric heating devices and for feeding hot water into heating circuits for the purpose of space heating. The tankless water heater can also be used in a modified design for warming/heating liquids other than water, which in particular would necessitate a different material selection for the helical tubes arranged in it, wherein the helical tubes are also given a different tube diameter and a different spiral design dependent thereon. The great advantage of the invention consists in the fact that the liquid to be heated does not come directly into contact with the electric heating elements, which rapidly leads to scale in the case of water, but instead heating elements lie in a limited space in a rod-shaped manner in the midst of helical tubes through which water or other liquids flow and their heating energy is delivered to the helical tubes indirectly via an inert medium located in the aforesaid limited space and by convection. A preselected temperature of the liquid to be heated is detected via sensors at the outlet and inlet of the device and internally controlled in such a way that the preselected temperature remains constant for every extracted liquid quantity.

Description

 Containerless hot water heater

The invention relates to a container-free hot water heater, both to supply a house with hot household water on the use of electrical heaters as well as for feeding hot water in heating circuits for the purpose of space heating.

The containerless hot water heater is used in a modified form also for heating / heating liquids other than water, which would make a different choice of material in particular for the arranged in it helical tubes necessary, the helical tubes also with respect to a variable diameter of the coiled tube and in this sense trained spiral obtained.

The great advantage of the invention is that the liquid to be heated does not come into direct contact with the electrical heating elements, which quickly leads to scale in water, but instead arranged heating elements in a limited space, rod-shaped in the midst of water or with other liquids flowing through helical tubes and their heating energy is discharged indirectly via an inert medium located in the aforementioned limited space and convection to the helical tubes. A preselected temperature of the liquid to be heated is detected via sensors at the outlet and inlet of the device in such a way and controlled internally that the preselected temperature remains constant for each amount of liquid removed. From the prior art, a variety of solutions are known in which, with the aid of electrical heating energy, in particular hot water is prepared, namely in direct contact of the water and therein immersed electrically heated heating rods, -wendein or the like. According to this principle, the so-called instantaneous water heaters work, which usually still provide different tempered water in some adjustable heat settings. However, it is not resolved that with prolonged removal of hot water by the simultaneous cold water inlet, the temperature of the desired hot water drops sharply and reheating after closing the hot water removal must be done. Another disadvantage of such devices is that in areas with high degrees of water hardness, scale build-up covers the heating elements and thus greatly limits the efficiency.

Representative of the state of the art working according to the aforementioned principle shall be briefly discussed below on the documents known from the patent literature. Thus, according to US 6,909,843 Bl an electric water heater is offered, which is divided into different departments to produce a defined hot water temperature and quantity. Flow rates of the withdrawn hot water between 12 and 20 gallons per minute and constant temperatures within the individual withdrawal quantities of 100 ⁰ F to 180 ° F should be achieved.

A special valve design regulates the permissible flow rates as a function of the fluid pressure in the supply and discharge lines. According to this principle, no continuous control of the temperature is given, the heating departments are retrieved separately from each other and it can be generated within the liquid quantities of constant temperature and flow rates. Mixtures between the specified limits do not take place. It is also no preheating, without immediate maintenance of the heating elements, possible. However, the main drawback here is that the sensor-controlled heating elements come into direct contact with the water to be heated.

No. 6,240,250 B1 proposes a compact internal double-element water heater.

The device contains in its upper part a connection of several cold water inflows to a hot water drain with appropriate shut-off valve. Cold water is passed from top to bottom, filling four separate chambers separated from each other. Two opposing chambers are each separated by a diaphragm, wherein a first of the two chambers of each side has no outlet and the cold water pressure therein acts against a first side or against the diaphragm, while the second of the two chambers of each side has a separate one Has flow for hot water and also has a heating element. The movable diaphragm triggers a microswitch, with which the heating elements are put into operation. When the hot water valve is closed, the pressure in the two chambers equalizes, the spring force on the diaphragm decreases and the two heating elements stop heating.

In principle, the abovementioned solution can be seen in analogy to the former, when it comes to the fact that heating elements come into direct contact with the water to be heated. It differs only in that the regulatory mechanism of Switching the heating elements is solved differently. There are also the disadvantages of not maintenance-free operation of a device here.

According to these statements, it can be seen that the technically known solutions so far have been aimed at perfecting hot water heaters which function according to the classic "immersion head principle", considering the conditions under which water removal can achieve the desired temperature conditions, aspects of as long operating life as possible without any maintenance requirements An energy-saving and simple and space-saving design has hitherto not been emphasized in principle, which is to be changed with the solution according to the invention.

It is therefore the object of the invention to propose a solution with which tankless a liquid, in particular water, can be made constant in a pre-settable temperature level, irrespective of the withdrawal amount, the electric heating elements via an inert liquid medium surrounding an indirect heating of the cause flowing through coiled liquid transport pipes water, while an energy saving function, by means of the already constantly at a certain temperature level inert liquid medium, with a view to delayed Einschaltzyklen the heating elements is achieved, the device works largely maintenance-free and made of relatively few components consisting of uncomplicated and in addition to Hot water preparation can also be used to operate a space heater. Furthermore, the containerless hot water heater should be hedgeable in its specific training against freezing if necessary. Failure of the power supply and have means of integrated circuits control options to prevent overheating and a display for notifying an evaluable test error codes.

According to the invention the object is achieved as follows, reference being made to the basic inventive idea of claim 1. The further embodiment of the invention results from the claims 2 to 8.

The following additional information on the teaching of the invention are required. In a rectangular and relatively flat forward-opening housing made of sturdy sheet metal are all elements for supply, distribution, dissipation and defined heating z. As of drinking water, the liquid of a space heating system or other liquids and the associated monitoring elements for detecting and forwarding determined operating conditions, which evaluated via an integrated circuit of a printed circuit and continuously adjusted to secure a pre-selected via input keys a Tableaus temperature to a certain level become.

The construction of the containerless hot water heater can be described as follows.

In the lower part of the compact housing is located, occupying about half of the existing space, a liquid-tight pipe coil tank, in which one or more z. B. water-carrying helical tubes are placed horizontally, which are surrounded in the tube coil tank by a heat-storing, inert liquid. The inert liquid should have a lower freezing point than, for example, the helical tubes flowing through water.

In one or in the arranged to several helical tubes, the latter aspect is dependent on the amount of liquid volume, which should be available in a certain time unit and with a desired temperature level, are centrally positioned horizontally rod-shaped heating elements, which are then put into operation when the temperature preset via the input keys on a proportional controller is no longer measured by means of an outlet sensor on the hot water outlet during a liquid extraction. An analogue function is carried out by an inlet temperature sensor, which is located after the cold water inlet before the cold water enters the tube coil tank, just like the outlet sensor, in a T-piece. The mutual interaction of said sensors consists of the following: If there is a need for hot liquid and an extraction takes place, the inlet temperature sensor detects a temperature drop in the incoming cold liquid and the heating elements are switched on, the required heating energy being determined by means of the proportional controller Temperature difference between the inlet temperature sensor and the outlet temperature sensor is monitored. The sensors used behave redundantly to one another and ensure that the tank-free hot water heater remains functional even if one of the sensors fails. If the need for hot liquid expires or falls, the outlet temperature sensor is activated a rise in temperature, whereupon the proportional controller throttles the supply of energy to / to the heating element / heating elements. As soon as the pre-set temperature is reached in the coil coil tank and all sensors, the energy supply to the heating element (s) is interrupted. The containerless hot water heater is then in standby mode.

A controllable anti-freeze circuit prevents the temperature in the tube coil tank from falling below a set value, thus preventing freezing of the existing coil tube (s).

Since the inert medium in the tube coil tank - also acts as a "buffer" - stores heat and the coil or the coil due to the spiral shape of known metallic properties can absorb temperature fluctuations elastic, the containerless hot water heater can not be damaged in principle in its function.

In addition to the protection circuit against freezing, the device has several thermal overload sensors, which are housed in the pipe coil tank and there not only monitor the temperature in the pipe coil tank, but also switch off the entire device in case of overload. The overload sensors are coupled to the main power supply relays of the controlling proportionality controller so that each time the temperature is exceeded, the line to the relay coil is disconnected or closed, opening the main power relay and disconnecting the heating elements from the power supply. The overtemperature contactors reset themselves so that the user does not have to intervene to restore the device to a ready state. A BIT (Built-In Test Flag) may be sent to the controller in the event of an error, and after a preset number of over-temperature conditions have been registered, a coded error message will be issued on the LED display on the front of the device.

The Proportionality Controller has a built-in Start Damping feature that prevents the power supply to the heaters from being fully turned on and off abruptly, which can cause voltage drops in the rest of the building or dwelling with the result that lights flicker or other visible electrical noise may occur. The containerless hot water heater can be energetically lowered into a resting or standby condition due to absence or weather conditions. It still has the protective function against freezing.

The invention will be explained with reference to an exemplary embodiment. The individual figures show:

Figure 1: Front view of the open tankless hot water heater (perspective

Presentation)

Figure 2: Opened tube coil tank (perspective view) Figure 3: Electrical circuit diagram (schematic diagram)

The reference symbols used mean:

1 - Cold water inlet 9 - Inlet temperature sensor

2 - Pipe tank 10 - containerless hot water heater

3 - T-piece 11 - cover

4 - heating element 12 - helical tube

5 - Proportionality controller 13 - Reflective plate

6 - outlet temperature sensor 14 - screw-in opening

7 - hot water drain 15 - supply opening

8 - Control buttons 16 - Ground 17 terminal strip

18 - Transformer

19 - printed circuit

20 - control line

21 - thermal overload switch

22 - energy supply

A containerless hot water heater 10 has in the present embodiment, two in a tube coil tank 2 horizontally disposed helical tubes 12, in which also inserted horizontally positioned heating elements 4 in the horizontal position and are firmly connected to the housing of the containerless hot water heater 10. Within the tube coil tank 2 is a heat energy storing inert liquid, the has the property of an oil, wherein the applied with cold water through the cold water inlet 1 or flowing through tubes 12 - each comprising a reflective plate 13 from three sides - take over the heat energy emitted by the heating elements 4 indirectly.

The level of the required energy supply for the heating elements 4 can be controlled by the specification of a controllable via control buttons 8 on the proportionality controller 5 temperature and thereby constant up to a maximum removable amount of hot water, inlet and outlet temperature sensors 9, 6 at the T-pieces. 3 transmit their temperature readings to the proportional controller 5 for further evaluation, which activates or deactivates the heating elements 4 to achieve the desired temperature level with respect to a current hot water removal quantity via control commands which can be derived therefrom. The switch-on of the heating elements 4 are reduced by the "heat-buffering" oil liquid in the tube coil tank 2 and by further action of acting outwardly isolation of the tube coil tank 2.

The containerless hot water heater 10 can be increased in terms of its capacity deliverable hot water by further integration of helical tubes 12 with heating elements 4, while expanding the tube coil tank 2. In a simplified representation, an overview of the electrical / electronic mode of operation of the containerless hot water heater 10 is shown in FIG. It should again be emphasized that the container-free hot water heater 10 is not only used to produce hot household water, but also as an alternative to conventional heating systems - acting on the basis of natural gas / petroleum - for space heating in z. B. single-family homes can be seen, since the electric energy, if necessary. Originating from Fotovoltaikanla- gen, very efficient and is usable in total no environmental impact.

According to Figure 3, the wiring of the already partially mentioned electrical components is shown in a simplified representation.

The understanding of the operation of the components used in it follows from their arrangement to each other.

The advantages of the invention can be summarized as follows: - Microprocessor-controlled proportional controller for maximum energy efficiency

- User selectable temperature settings for both power and sleep modes.

- Built-in anti-freeze circuit

- Soft-start function to avoid voltage peaks in the power supply lines

- Built-in heat overload protection and factory-set safety features

- High performance insulation and thermal barriers to minimize energy losses

- Self-contained circulatory system to meet all drinking water conditions

- User-selectable sleep (sleep) mode to minimize energy consumption.

Claims

claims 1. Containerless hot water heater (10), consisting of a metallic housing with a cover (11) and with a cold water inlet (1) and a hot water outlet (7), characterized in that a tube coil tank (2) filled with an inert liquid is, horizontally arranged and centrally provided with heating elements (4) and liquid-flowed helical tubes (12), wherein at one of the cold water inlets (1) and at one of the hot water drains (7) of one of the helical tubes (12) T-pieces (3) are present, in which the inlet temperature sensors (9) and outlet temperature sensors (6) are located and which are connected via the evaluation of the temperatures of the aforementioned sensors specifically with electric energy heated heating elements (4) by means of a proportional control (5) on or off. 2. Containerless hot water heater (10) according to claim 1, characterized in that the helical tubes (12) with reflective plates (13) are covered on at least three sides. 3. Containerless hot water heater (10) according to claim 1, characterized in that the inert liquid of the tube coil tank (2) is a heat-storing oil. 4. A containerless hot water heater (10) according to claim 1, characterized in that it can activate an electrical circuit against the risk of freezing, regardless of an electric power failure. 5. Containerless hot water heater (10) according to claim 1, characterized in that in the tube coil tank (2) thermal overload sensors are arranged, which trigger in the event of overheating overtemperature contactors, via the control of the proportionality controller (5) the relay of the main power supply for the heating elements (4) interrupt. 6. Containerless hot water heater (10) according to claim 1, characterized in that an internal test error code can be displayed on an LED display on the proportional controller (5). 7. Containerless water heater (10) for use in heating other liquids than water. 8. Containerless hot water heater (10) for the purpose of heating circuits of space heating in single-family homes.