DK200200188U3 - Water heating system for heating domestic water in a water heater - Google Patents

Abstract

In order to tap bacteria-free hot domestic water at a tapping point, such as a wash basin, shower and similar point of use, in a simple manner, use is made of a method according to the invention which incorporates a heat exchanger (4), from whose secondary side the hot domestic water (18) is tapped directly and without being mixed with domestic water already heated. The risk of bacteria, including the feared legionella bacteria, is eliminated hereby, since no hot water is left between the tappings, as the heating takes place only in connection with the tapping. The heat exchanger (4) may be included in a water heater (1) which may be installed directly at the tapping point, thereby making the installation very compact and direct such that a high water rate and a low consumption of energy are ensured.

Description

DK 2002 00188 U3

WATER HEATING SYSTEM FOR HEATING WATER WATER IN A WATER HEATER

The prior art

The generation relates to a water heating system for heating domestic water in a water heater with a heat exchanger whose primary side is allowed hot water and whose secondary side is allowed colder water.

Hot water, especially in larger plants, is often of poor quality, with bacterial growth and mucus due to physical / bacterial conditions.

Bacterial growth can be pathogenic, and where legionella is present, there is a risk of legionnaires' disease.

This disease is an airway infection which can be fatal when it occurs in hospitals etc. with immunosuppressed patients.

The factors that have the greatest influence on the bacterial growth in the water are the temperature, the residence time of the water in the pipe system and the area of the internal surfaces. Bacterial growth occurs especially at temperatures between 20 ° and 50 ° C, long residence times and large surfaces.

The traditional way of countering the risk of bacterial growth is to keep a relatively high water temperature, or to drain all the water heated in the container and possibly. flush out sludge formation as needed. However, it is a problem that the heated water from the container and in the wiring to the tapping point often stands still between the taps, thereby losing temperature with the resulting opportunities for bacterial growth.

To remedy this disadvantage, it is known from Japanese Patent Application 101 959 45 2 DK 2002 00188 U3 to sterilize the hot water in a heat exchanger, electric water heater, in a container from which a limited amount of sterile water can be drained.

The disadvantage of this is that the stagnant water outside the tapping periods constitutes a relatively large amount of water corresponding to the volume of the container, which water must be sterilized before it can be drained. This requires both time and energy, in addition to the risk of scalding damage.

Furthermore, from EP 621 450 A2 a water heating system for heating domestic water is known through a heat exchanger with heat supply via a buffer vessel.

This buffer tank is needed where the heat source is limited such as with solar heating systems. In order to ensure a suitable use water temperature from the beginning of the bottling at the bottling point, circulation of the tap water is installed. This means that in the circulation line there will always be a water temperature of about 40 ° C, precisely the temperature which is the optimal propagation temperature for iegionella bacteria. As the circulation line has a length at least equal to the double distance between the exchanger and the tapping point, this means that a relatively large amount of water that is constantly kept heated to about 40 ° C will pose a significant risk of infection. In this connection, it should be remembered that the bacterial growth under these conditions doubles at least every two hours.

Purpose of production:

The purpose of the generation is to remedy these shortcomings and disadvantages, and this is achieved according to the generation by a water heating system where the water on the secondary side of the water heater, ie the hot utility water, is drained directly from the heat exchanger without being mixed with already heated water.

In this simple way, the risk of bacteria in the tapped heat is reduced for the simple reason that the propagation of the Legionella bacteria during the periods between the taps cannot take place, as the heating and the tapping take place simultaneously, thereby leaving no water. , in which bacteria can thrive.

The installation can therefore be made so compact and the mains network so direct that a high water velocity, low return and return temperature as well as minimal storage of stagnant water can be achieved. In addition to low installation costs, it also results in low energy consumption.

The heating takes place when the tapping is started, and it takes place completely at the tapping point itself. This provides the greatest possible assurance that the water does not contain the dreaded Legionella bacteria.

By supplying district heating water or possibly hot domestic water as claimed in claim 2 to the primary side of the heat exchanger, a simple installation is obtained, since existing hot water installations can be used already, thereby considerably reducing installation costs.

By providing fresh cold water to the secondary side of the heat exchanger as claimed in claim 3, assurance is obtained that it will not be mixed with previously heated water.

By regulating the water supplied to the primary and secondary side by means of a pressure controlled regulator, as defined in claim 4, the operation of the system is ensured, since the regulator will act as an on / off valve at start-up and end of the tap.

Finally, as claimed in claim 5, it is expedient to control the tapping by means of solenoid valves, thereby being able to automate the tapping and control its course.

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the drawings:

An example of an embodiment of an installation according to the invention will be described in more detail below with reference to the drawing, which shows a perspective view of a water heater and with a partially cut-away housing.

Description of embodiment:

The example of an embodiment of a water heater 1 illustrated in the drawing is constructed on a backplate 3 which can be fixed to the wall just above the tapping point so that the drained water 18 exits the water heater through the outlet line 17 directly and not through valves, outlet nozzles and the like. .

To the primary side of the heat exchanger 4 is fed hot media 5, which can either be district heating water or existing hot water supply through a stud 6, pipeline 15 and a solenoid valve 12.

To the secondary side of the exchanger 4, fresh drinking water 7 is supplied through a stud 8 and a regulator 9.

The controller 9 is preferably of the kind described in Danish utility model registration no. 2000 00320.

The draining of the heated domestic water 18 from the secondary side of the exchanger 4 is effected via a temperature sensor 13, which is connected via a capillary tube 14 to the regulator 9 and to a solenoid valve 11 inserted on the outlet line 17.

The heated and now cooled media is diverted from the primary side of the exchanger 4 through the regulator 9 to an outlet line, as illustrated by arrow 16.

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A switch 19 connects the current to the water heater including the solenoid valves 11, 12 and a microprocessor not shown and various control lamps 20 on the front of the cabinet 2. Finally, there is a water temperature regulator 10 on the regulator 9 for determining the temperature of the hot tap water 18.

The regulator 9 and valves 11, 12 are made of drinking water approved materials. The exchanger 4 is preferably soldered of pure copper or silver, and the pipes and exchangers are preferably made of acid-resistant stainless steel AISI 316. The exchanger and the pipes can be cleaned and supplied with chlorine in reasonably high concentration without corrosion and are made in minimal pipe dimension and exchanger size so that at each tapping, a strong flow and large exchange of water occurs in a predetermined amount, temperature and time, which in turn causes degraded environment for biofilm formation, protozoa and thus propagation of the legionella bacteria.

Outside of the tap period, there are approx. 3 dl. stagnant water in the exchanger 4. Unlike containers and / or long tubes of larger diameter with many times larger stagnant water volumes and thus a potential, far greater risk of legionella problems. If necessary, the exchanger 4 can be flushed automatically only with respect to the use water in x-number of times / time / day, so that the limited amount of stagnant use water in the exchanger is replaced according to the specific need, which is dependent on specific propagation conditions for the legionella bacteria.

The temperature of the stagnant drinking water must be lower than 20 ° C or higher than 50 ° -60 ° C to prevent the propagation of the legionella bacterium. The exchanger 4, as mentioned, soldered with pure copper or silver, delivers copper or silver ions to a minimal extent to the stagnant water in the exchanger 4, which can at the same time limit the bacterial propagation environment and reduce the number of bacteria.

For heating the primary side of the exchanger, district heating water is usually used, but according to the production, the secondary water which is already heated to 50 ° C and which is in the existing hot water network can also be used as heating medium. This method of heating can give use water of 40 ° -45 ° C. This avoids, inter alia, lime precipitation and scalding.

Using the already heated domestic water as a heating medium, which often contains an undesirable number of Legionella bacteria, can be of particular practical importance when renovating and not least where there are older, long pipe installations, since the water heater 1 can only be mounted directly over - and continue to use - the existing ex. wash basin and connect to the existing hot water tap as a heating media source regardless of the content of legionella bacteria. This simplifies and cheapens the installation.

There is no need for a mixer battery or other option for mixing the tap water with "old" possibly legionella infested, heated tap water - just a drainpipe.

In the water heater 1, there is only one tap option for cold and / or hot tap water, which comes directly from the exchanger 4 to the point of consumption. No faucet / valve is required. The heated domestic water needs to reach the area as quickly and directly as possible. The system can thus replace previously used luminaires.

On the system are mounted one, two or more solenoid valves 11, 12. Basically one on the secondary side and one on the primary side, each and independently controlled by a microprocessor.

On the tap water side, the solenoid valve 11 - also for safety reasons - is supplemented by a pressure controlled regulator 9.1 in cases where only a solenoid valve is fitted and the solenoid valve possibly fails ex. due to impurities or other malfunctions, the use water will in such cases undesirably continue to run 7 DK 2002 00188 U3. Here, however, the pressure-controlled regulator 9 comes into operation, since the pressure-controlled regulator will always function with an on / off function at start-up and end of the drain.

A non-magnetic solenoid valve may also be supplemented in cases where a portion of the primary and / or secondary water is used, e.g. it is desirable to supply the sewerage system for a shorter or longer period directly before or after finishing, cf. set out below.

For example, the system can optionally be set for activation with simultaneous opening to / of the primary and secondary side. However, short waiting times may occur here, for example, if the utility water is heated to 40 ° C because the heating medium must heat the wiring harness and the exchanger and / or be set to activate the secondary side first in x-number of time and / or quantity units and / or temperature-determined so that fresh water is supplied to the exchanger until the "old" stagnant water is rinsed before the primary side is connected. The secondary side can, with an additional solenoid valve instead of the sink, be directed directly to the sewer until the primary side comes into operation, and / or to the desired DHW temperature is obtained and / or set to activate the primary side first in x-number of time and / or quantity units and / or temperature-determined such that the heated DHW in the exchanger has the desired temperature before opening to the tapping point or starting the primary and secondary side simultaneously and so that the secondary side is first fed directly to the sewer until the required drinking water temperature is obtained and then direct ex. to the sink.

This results in partly that the secondary side is flushed with / to clean, cold hot water, and partly that the hot water temperature has the desired temperature when the tapping point comes into operation and / or is set for activation only on the secondary side with predetermined time interval in x-number of time units or quantity per . time regardless of whether the water heater 1 has been a person affected for use or not in the short or long term, or similarly automatically activated x-number of time units 8 DK 2002 00188 U3 units after the last taping, so that the secondary side always contains the use water of an optimal quality, whether the plant is personally activated or not in the short or long term and / or set to activation so that upon completion of the desired tapping, the primary side stops immediately, while the secondary side continues the flow in the exchanger in x-number of time and / or quantity units and / or temperature determined for sewage to immediately cool the exchanger 4 and thus also the "stagnant" water in the exchanger 4 to the desired temperature below 20 ° C, for example, to prevent the Legionella bacteria from multiplying.

The process can also be reversed so that after the final taping, the primary side is activated only in x-number of time units / quantities and / or temperature-determined, thereby raising the temperature of the use water, the "stagnant" water in the exchanger 3 dl to the desired temperature ex. 60 -70 ° C to destroy any Legionella or other bacteria, however, this does cause a water spill and can cause scalding and / or calcification of the exchanger, however, the latter is a minor problem as it can be acidified as a coffee maker and / or set to activation so that the temperature range of the exchanger on both the primary and secondary side, regardless of activation of the tapping point, is always at least 50 ° C and possibly below 50 ° C after tapping has begun, for example due to scalding risk by limiting the propagation ability of the legionella bacterium or also excluded during the standstill period of the water heater.

Depending on the composition of components used, including the microprocessor, the alternative combination and safety options are manifold and / or set to activate so that the use water in ex. a buffer container with optimum temperature and / or time horizon for any. to kill bacteria and the like located immediately in front of the water heater 1, and then to subsequently cool the utility water from the buffer vessel to the exchanger 4 - which instead of receiving ex. district heating water 5 - instead of in this case cold / cooled water which can be recycled and thus first bring the optimally heated and stored container use water down to the desired tapping temperature at 9 DK 2002 00188 U3.

The temperature of the domestic water is generally controlled by a thermostat 10, which can be connected to a pressurized domestic water part to obtain an optimal solution in terms of both safety and temperature. The thermostat 10 can be adjusted immediately to the desired circular temperature.

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REQUIREMENTS

5 1. Water heating system for heating domestic water in a water heater (1) with a heat exchanger (4) whose primary side is allowed hot water (5) and whose secondary side is allowed colder water (7), which is new in that the water (18) the secondary side is drained directly from the heat exchanger (4) without being mixed with already heated water.

A water heating system according to claim 1, which is new in that the hot water (5) on the primary side is constituted by district heating water or hot domestic water.

A water heating system according to claim 1, which is new in that the water (7), which is supplied on the secondary side, is fresh water.

Water heating system according to claims 1-3, which is new in that the entrained water (5, 7) for the primary and secondary side is regulated by a pressure controlled regulator (9).

Water heating system according to claims 1-4, which is new in that the discharge of the heated domestic water (18) is controlled by a solenoid valve (11, 12) on the secondary side and the primary side respectively.

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