WO2000029789A1

WO2000029789A1 - Accumulation vessels for hot water heating systems

Info

Publication number: WO2000029789A1
Application number: PCT/NL1999/000691
Authority: WO
Inventors: Johannes Petrus Wesseling
Original assignee: Johannes Petrus Wesseling
Priority date: 1998-11-13
Filing date: 1999-11-11
Publication date: 2000-05-25
Also published as: AU1190800A; NL1010546C1; EP1157240A1

Abstract

Hot water heating system for use with central heating of living space accomodations, comprising one or more heating units for heating of circulation water, one or more heat emission points for emmission of heat by the circulation water, a system of pipelines for the circulation of the circulation water from the heating units to the heat emission points and back again, characterized in that in the system an accumulation vessel is provided, with at least one hot water inflow pipe for the intake in the vessel of hot water from the heating unit, with at least one hot water outflow pipe for the leading away of hot water from out of the vessel to the heat emission points, with at least one cold water inflow pipe for the intake of cooled off water from the heat emission points, and with at least one cold water outflow pipe for the leading away out of the vessel of cooled off water to the heating unit.

Description

Accumulation vessels for hot water heating systems.

The present invention relates to hot water heating systems for use with living space accomodations, com- prising a heating source such as a boiler for the heating of circulation water, several heat emission points such as radiators for the emission of heat to the living space accomodations by means of the hot circulation water and a system of pipelines for the circulation of heated and cooled off circulation water from the heating source to the heat emission points and back.

The present invention further relates to tap water heating systems for the use of hot tap water for sanitary purposes and kitchen use in said living space accomodations.

Such heating systems are known.

The present invention relates to an accumulation vessel, in which both above-mentioned systems are integrated. Characterizing for the accumulation vessel is a layered temperature build up of the in- and out- flo- wing circulation water within the vessel. The layered building up of temperature is essental for the well functioning of the accumulation vessel.

The present invention aims to provide an accumulation vessel in which hot circulation water from the heating source first is accumulated and separated before this is further transported to the heat emission points. Cooled off circulation water from the heat emission points is first accumulated and separated in the accu- mulation vessel and isolated before this is further transported to the heating source. In this manner both of the connected circuits are separated hydraulically from each other by means of the accumulation vessel, whereby each circuit can operate independant and optimal.

The present invention aims to provide an improved hot water heating system for extra energy saving as a result of efficiency improvement, universal connection of diverse heating sources, improved operation of the hot tap water system and improved operation of the heating systems in the living space accomodations.

The hot water heating system for heating of living space accomodations according to the invention is characterized in that in the system an accumulation vessel is provided, by means of which the system is functionally separated in two, a separate circuit for the heating source (a boiler circuit) and a separate circuit for the heat emission points (the radiator circuit) . The accumulation vessel is therefore provided with at least one hot water inflow pipe for the intake in the accumulation vessel of heated hot circulation water from one or more heating units, with a cold water outflow pipe for the leading away out of the vessel of cooled off water to one or more heating units, with a hot water outflow pipe for the leading away of hot circulation water from out of the vessel to the heat emission points, and with at least one cold water inflow pipe for the intake in the accumulation vessel of cooled off cold circulation water from the heat emission points.

With this it is aimed for that both circuits, independant from each other, can function optimal with as a result an improvement in comfort and efficiency.

The accumulation vessel according to the invention has the characteristic that each hot and cold water inflow pipe is provided with an inflow construction which transforms turbulent flow patterns in the connection pipe into laminar flow patterns within the accumulation vessel, whereby a layered building up of temperatures of the in- and outflowing circulation water is obtai- ned.

The inflow constructions according to the invention take away the speed of the inflowing circulation water during the passage through two metal plates disposed at short distances from each other, one behind the other, which plates are provided with a certain pattern of apertures. The inflow constructions are connected within the accumulation vessel to riser and fall pipes of which the walls are provided with slit-shaped perfo- rations, through which the inflowing circulation water can flow out at the upper side, the bottom side as well as sideways. With this it is obtained that a layered building up of temperatures of inflowing water temperatures is brought about, hot circulation water in top, cooled off circulation water at the bottom and warm circulation water in layers in between.

The accumulation vessel according to the invention has the characteristic that also outflow constructions are provided. These outflow constructions are dependant from the positioning of the outflow pipes for hot, warm and cooled off circulation water from out of the vessel. The outflow construction for the leading away of cooled off circulation water from out of the accumulation vessel to the heating sources is provided as an outflow opening at the bottom of the accumulation vessel. The outflow pipe for the leading away of hot and warm circulation water from out of the accumulation vessel to the heat emission points and/or the heating source (boiler) is provided as an open insert pipe, which opens into approximately the middle of the vessel. The length of the insert pipe is determined by the power relation of the hot tap water installation and the central heating installations involved for a certain type of accumulation vessel.

The accumulation vessel according to the invention has the characteristic that the outflow constructions functionally separate the content of the accumulation vessel in two, in a top volume and in a bottom volume corresponding to the above-mentioned power relation of the hot tap water installation and the central heating installation.

The upper side of the insert pipe is the natural separation surface for the said top and bottom volume.

The accumulation vessel according to the invention has the characteristic that inflowing hot circulation water through the riser pipe primarily flows to the top volume and secondary to the bottom volume. The top volume therefore is, for the inflowing hot circulation water, in a preferred arrangement relative to the bottom volume. With this it is aimed for that the heating capacity of the upper volume is intended for the hot tap water installation and the heating capacity of the bottom volume is intended for the central heating installation.

The accumulation vessel according to the invention has the characteristic that the vessel is provided with a closed insert pipe for inserting control thermostats for controlling the temperature of the circulation water in the top volume and/or the bottom volume of the accumulation vessel. For controlling the temperature of the circulation water in the top and/or bottom volume of the accumulation vessel three control thermostats are provided, a single thermostat for controlling the on and off swit- ching of the heating source for the top volume and two thermostats in cascade arrangement for on- and off switching of the heating source for the bottom volume, whereby the bottom thermostat switches the heating source on and the upper thermostat switches the heating source off. With this a permanent high temperature is obtained of the circulation water for hot tap water in the upper volume and/or a maximum volume of cooled off water in the bottom volume for optimizing the effi- ciency of the heating source (boiler efficiency) .

The control thermostats can be combined with an outside thermostat for gradual control of temperature of the circulation water. With this a winter operation, a spring and autumn operation and a summer operation is realized. During summer operation the central heating function for the bottom volume is switched off, whereby the bottom volume becomes completely available for the solar energy installation. With this it is achieved that the accumulation vessel also functions as a solar boiler, such that solar energy that is available can be used optimal for the hot tap water as well as the central heating installa- taion with as a result an extra energy saving. For after heating of the solar energy in the top volume in the outflow pipes to the boiler three-way valves have to be provided.

The accumulation vessel according to the invention has the characteristic that in the upper volume of the accumulation vessel a tap water spiral is provided for use of hot tap water in living space accomodations. The tap water spiral is provided of copper pipe with an outwardly enlarged heating surface with an open structure, through which circulation water can more or less freely flow.

The tap water spiral according to the invention has the characteristic that this is provided inwardly with a circulation casing, by means of which a circulation shaft is provided. With this a natural circulation of hot and cooled off circulation water in the circulation shaft is obtained. At the top side hot circulation water flows in the circulation shaft along the tap water spiral. The hot circulation water cools off along the tap water spiral and the cooled off circulation water falls down in the circulation shaft. With this a heat exchanger is obtained according to the principle of cross and counter current for an optimal heat exchange of the circulation water to the hot tap water.

Because of the natural circulation according to the invention of hot circulation water along the tap spiral, cold tap water running through the tap water spiral is heated to hot and warm tapwater.

In the outflow pipe of the tap spiral according to the invention a hot water tap point is provided for kitchen use and a tap water thermostat is provided for warm water use for sanitary purposes.

With the construction of a tap water spiral in the top volume it is aimed for to obtain a warm water device according to the flow through and storage principle with an optimal output of hot and warm tap water for kitchen use and for sanitary purposes in living space accomodations .

In the circulation casing of the circulation shaft according to the invention slit shaped perforations are provided which are formed in such a way that cooled off circulation water can flow out at the sides from out of the circulation shaft to a corresponding temperature level of the layered temperature building up of circulation water within the accumulation vessel. With this it is aimed for that the natural circulation can opera- te optimal and that the layered temperature building up remains maintained.

The accumulation vessel according to the invention has the characteristic that the bottom volume of the accumulation vessel is intended for the central heating installation. The bottom volume is in turns recharged by the heating source (s) and uncharged by the heat emission points. The bottom volume according to the invention is dimensioned in such a way that, during the heating season, at an average of two to three times per hour the bottom volume is recharged and uncharged. With this it is aimed for that the number of burner switches of the boiler is substantially reduced, with as a result less maintenance of the boiler, long life and an improved efficiency of the boiler.

The hot water heating system according to the invention has the characteristic that the system of accumulation vessel has a modular nature, that is to say, that the top and bottom volume are dimensioned such that this gradually corresponds with the conventional powers of hot tap water installations and central heating instal- lations for living space accomodations. With this it is aimed for that for each desired combination hot tap water power and central heating capacity modular an optimal accumulation vessel is available.

The hot water heating system according to the invention has the characteristic that by the use of separate central heating and radiator circuits, the central heating unit can operate optimal as a low water temperature system, whereby it is aimed for that the tempe- rature of the return water is as low as possible. The cooled off circulation water of the low water temperature system is accumulated in layers in the bottom volume of the accumulation vessel. The volume of cooled off circulation water is lead through the cold water outflow pipe to the heating source (s), with which an improvement of the efficiency of those heating sour- ce(s) is aimed for.

The accumulation vessel according to the invention has the characteristic that in top of the vessel een expansion volume is provided for accumulating expansion water from the alternating heating and cooling of circulation water in the accumulation vessel and in the connected circuits. With this it is aimed for that the expansion volume can take the place of the conventional expansion vessel.

The hot water heating system according to the invention has the characteristic that the accumulation vessel by means of the expansion volume is the hydraulic zero point for all the connected circuits, with which it is aimed for that each desired heating source can be universally connected.

The invention will now be described further with reference to the drawings of a number of embodiments .

Figure 1 shows a schematic view of the hot water heating system according to the invention, with a side view in longitudinal section of the accumulation vessel with several connected circuits according to the inven- tion.

Figure 2 shows a top view in cross section of the accumulation vessel with inflow constructions according to the invention. Figure 3 shows a side view in longitudinal section of the accumulation vessel with inflow constructions complete with riser and fall pipes according to the invention. Figure 4 shows a side view in longitudinal section of the accumulation vessel with outflow constructions and a volume partition in an expansion volume, a top volume and a bottom volume, according to the invention. Figure 5 shows a side view in longitudinal section of the accumulation vessel with in the top volume a tap spiral for hot tap water complete with circulation casing according to the invention.

Figure 6 shows an overview of several connection possi- bilities of several durable and non durable heating sources.

As can be seen in figure 1, in the hot water heating system 1 for central heating of living space accomoda- tions an accumulation vessel 11 is centrally arranged, to which are connected one or more heating sources 2 and 3 for heating of hot circulation water 4 , several heat emission points 5 and 6 for the emission of heat by hot circulation water 4, a tap water spiral 7 for heating of cold tap water 8 to hot tap water 9 by hot circulation water 4, which circulates internally in the vessel according to the thermosiphon system, and a system of pipelines for the external circulation of hot and cooled off circulation water 4 and 15 by means of circulation pumps 29 from and to the heating sources 2 and 3 and the heat emission points 5 and 6. The accumulation vessel 11 is formed with at least one hot water inflow pipe 12 for the intake in the accumulation vessel 11 of hot circulation water 4 from the heating source (s) 2 and 3, with a hot water outflow pipe 13 for the leading away of hot circulation water 4 from out of the accumulation vessel 11 to the heat emission point (s) 5 and 6, with at least one cold water inflow pipe 14 for the intake in the accumulation vessel 11 of cooled off circulation water 15 from the heat emission point (s) 5 and 6, and with a cold water outflow pipe 16 for the leading away from out of the accumulation vessel 11 of cooled off circulation water 15 to the heating source (s) 2 and 3.

As can be seen in figure 2, 3, 4 and 5, the accumulation vessel 11 can be carried out as a steel plate tank with a cilindrical body 17 and two welded bottoms 18. The steel plate tank can be installed standing or hanging and is provided on the outside with an isolation casing 19.

As can be seen in figure 1, 2 and 3 inflow constructions 20 are provided after the hot water inflow pipes 12 and after the cold water inflow pipes 14 which transform the turbulent flow patterns in the connection circuits to the inflow pipes 12 and 14 into laminar flow patterns 21 and 22 within the accumulation vessel 11.

The inflow constructions 20 are formed substantially by two metal plates 23 and 24 located at short distances one behind the other and which are provided with certain aperture patterns, whereby, as seen in the direction of the flow, the perforations in the metal plates 23 have another passageway than those of the metal plates 24 placed behind. In this manner the speed of the inflowing circulation water that passes the two perforated metal plates 23 and 24 is lowered in two steps, such that the turbulent flow patterns in the inflow pipes 12 and 14 are transformed into laminar flow patterns 21 and 22 within the accumulation vessel 11.

The inflow constructions 20 are connected within the accumulation vessel 11 to riser and fall pipes 25 which are provided in the pipe walls with slit-shaped perforations 26, through which the circulation water can flow out at the top side, at the bottom side as well as sideways. In this way a layered building up of several inflowing water temperatures can be realized, hot circulation water in top, cooled off circulation water with the lowest temperature in the bottom and warm water in layers in between.

The riser and fall pipes 25 are provided with a fine- meshed wire gauze 27 in which the obtained laminar flow patterns can be continued within the riser and fall pipes 25.

In the riser and fall pipes 25 inflowing hot circulation water 4 will rise up and inflowing cooled off circu- lation water 15 will fall down. If one of both temperature flows passes on its way a corresponding temperature level, that temperature flow will pass to the outside sideways through the perforations 26 to the temperature level involved, by which the layered tempe- rature building up is maintained optimal.

As can be seen in figure 1 and 4 the accumulation vessel 11 is provided with two outflow constructions 13 and 16, which are related to the positioning of the outflow pipes for hot, or warm, or cooled off circulation water 4 or 15. The outflow construction 16 for the leading away of cooled off circulation water 15 from out of the accumulation vessel 11 to the heating sources 2 and 3 is provided as the outflow opening 16 below in the accumulation vessel 11.

The outflow construction 13 for the leading away of hot circulation water 4 to the heat emission points 5 and 6, of warm circulation water 4 to the heating sources 2 and 3, is provided as an open insert pipe 30. The length of the insert pipe 30 is determined by the volume partition of the content of the accumulation vessel 11 in an top volume 31 and in a bottom volume 32. The volume partition of the top and bottom volume 31 and 32 is determined by the power proportion of the hot tap water installation 7 and 9 and the central heating installation 5 and 6 for a particular type of accumulation vessel for a particular living space acco odation.

The top side of the insert pipe 30 is the natural separation surface 33 of the top and bottom volume 31 and 32.

As can also be seen in figure 1, 4 and 6 an expansian volume 34 is provided in top of the accumulation vessel 11 for accumulating and recuperating of expansion water, that is a result of the temperature fluctuations which occur regularly of the total volume of circulation water in the accumulation vessel 11 and in the connected circuits.

The expansion volume is filled with a certain volume of air 35. The size of the expansion volume 34 is partly determined by the length of the open insert pipe 36, which is provided outside the accumulation vessel 11 with an automatic de-aerator 37. The expansion volume 34 replaces the expansion vessel in the conventional hot water heating systems and is more efficient in function and maintenance. By means of the expansion volume 34 the accumulation vessel 11 is the hydraulic zero point 38 for all the connected circuits, whereby each connected circuit can function optimal with its own independant volume flow and control.

As can also be seen in figure 1 and 4, in top of the accumulation vessel 11 a closed insert pipe 39 is provided for the insertion of control thermostats for the control of the temperature of the circulation water in the top and bottom volume and for starting the heating sources 2 and 3.

As can be seen in figure 1, 3, 4 and 5 in the top volume 31 of the accumulation vessel 11 a tap water spiral 7 is provided for heating of cold tap water 8 to hot tap water 9. The tap water spiral 7 is provided on the outside with an enlarged heating surface 40 for an optimal heat transfer of the hot circulation water 4 to the cold tap water 8. The tap water spiral 7 is on the inside provided with a circulation casing 41, by means of which a circulation shaft 42 is formed for bringing about a natural circulation of the circulation water according to the ther- mosyphon system. According to that thermosyphon system hot circulation water 4 flows at the top side into the circulation shaft 42, cools off along the tap spiral 7 and the cooled off circulation water 15 falls down in the circulation shaft 42. The circulation casing 41 is provided with slit-shaped perforations 43 through which the cooled off circulation water 15 can eventually flow out sideways to a corresponding teperature level in the layered temperature build up of the accumulation vessel. The tap water spiral is provided in top of the accumulation vessel 11 with connection pipes for the inflow of cold tap water 8 and for the outflow of hot tap water 9. The connection pipe for hot tap water 9 is provided with a tap point for hot water use in the kitchen and a tap water thermostat 10 for warm tap water for sanitary purposes .

As can be seen in figure 6 several alternative and/or durable energy sources can be connected universally at once or later.

Alternative and/or durable energy sources can be subdivided in:

- Individual installations; - Collective installations.

Individual installations can be formed by:

- Gas- or oilfired central heating boilers 2; - SOLAR-installations 3 with water circulating solar collectors;

- Heat pumps 43, on the basis of ventilating air of the living space, terrestrial heat, heat from industrial waste water, or from surface water;

- Total energy 44 with a hot gas motor. Collective installations can be:

- Block heating 45, 46 or 47, whereby the appartments are connected to a central boilerhouse and/or a total energy installation;

-District heating 45, 46 or 47, whereby the residences in the district are connected to for instance a waste heat installation or a STEG-unit;

- Urban heating 45, 46 or 47, whereby the residences are connected to a distribution network of industrial waste heat from for instance a waste incineration plant or a power station.

Claims

C l a i m s

1. Hot water heating system for use with central heating of living space accomodations, comprising one or more heating units for heating of circulation water, one or more heat emission points for emission of heat by the circulation water, a system of pipelines for the circulation of the circulation water from the heating units to the heat emission points and back again, characterized in that in the system an accumulation vessel is provided, with at least one hot water inflow pipe for the intake in the vessel of hot water from the heating unit, with at least one hot water outflow pipe for the leading away of hot water from out of the vessel to the heat emission points, with at least one cold water inflow pipe for the intake of cooled off water from the heat emission points, and with at least one cold water outflow pipe for the leading away out of the vessel of cooled off water to the heating unit.

2. Hot water heating system according to claim 1, characterized in that the opening of the cold water outflow pipe for the leading out of the vessel of cooled off water to the heating unit is located in the lower part of the vessel.

3. Hot water heating system according to claim 1 or 2, characterized in that the opening of the hot water outflow pipe for the leading out of the accumulation vessel of heated water to the heat emission points is located at a distance from the lower part of the vessel, more in particular substantially halfway the height of the vessel or in the middle of the vessel.

4. Hot water heating system according to one of the preceding claims, characterized in that the opening of the hot water inflow pipe for the intake in the vessel of heated water from the heating unit is located above the opening in the vessel of the cold water inflow pipe for the intake of cooled off water from the heat emission points.

5. Hot water heating system according to one of the preceding claims, characterized in that in the vessel one or more riser and fall pipes are provided.

6. Hot water heating system according to claim 5, characterized in that the riser and fall pipe is disposed vertically in the vessel.

7. Hot water heating system according to claim 5 or 6, characterized in that the riser and fall pipe opens out into the bottom part and into the top part of the vessel.

8. Hot water heating system according to claim 5, 6 or 7, characterized in that the riser and fall pipe is provided with perforations, more in particular slit- shaped perforations.

9. Hot water heating system according to claim 5, 6, 7 or 8, characterized in that the riser and fall pipe is provided on the inside with a wire gauze, more in particular a fine-meshed wire gauze.

10. Hot water heating system according to claim 5, 6, 7, 8 or 9, characterized in that the hot water inflow pipe and the cold water inflow pipe in the vessel are connected to the riser and fall pipe.

11. Hot water heating system according to claim 10, characterized in that the hot water inflow pipe and the cold water inflow pipe at the place where they are connected to the riser and fall pipe are provided with means, by which the turbulent flow patterns in the pipe are transformed into laminar flow patterns within the accumulation vessel.

12. Hot water heating system according to claim 11, characterized in that the means are formed by one or more perforated plates, such that the water flowing through these perforations passes the connection to the riser and fall pipe.

13. Hot water heating system according to claim 12, characterized in that the hot water inflow opening and the cold water inflow opening at the location where these are connected to the riser and fall pipe are provided with at least two perforated plates, one disposed behind the other, whereby, as seen in the direction of the flow, the perforations in the first plate have another passageway than the perforations in the plate located behind that.

14. Hot water heating system according to one of the preceding claims, characterized in that a hot tap water pipe is provided in the upper part of the vessel.

15. Hot water heating system according to one of the preceding claims, characterized in that in the vessel a cilinder is provided, of which the outer wall is located at a distance from the inner wall of the vessel.

16. Hot water heating system according to claim 15, characterized in that the hot tap water pipe is provided in the space between the outer wall of the cilinder and the inner wall of the vessel.

17. Hot water heating system according to claim 15 or 16, characterized in that the cilinder is provided with perforations.

18. Hot water heating system according to one of the preceding claims, characterized in that the accumulation vessel is formed by a steel plate tank which is intended to be installed standing or hanging.

19. Hot water heating system according to one of the preceding claims, characterized in that the hot water outflow pipe for the leading away of hot circulation water from the accumulation vessel to the heat emission points is located down below in the accumulation vessel, and is formed as an insert pipe of a determined length, which corresponds to a certain volume partition of the vessel, according to the power ratio of the hot tap water installation and the central heating installation.

20. Hot water heating system for use with central heating of living space accomodations, comprising a heating source, such as a central heating boiler, for heating of hot circulation water, several heat emission points, such as radiators, for emission of heat by the circulation water to the living space accomodations and a system of pipelines for the circulation of circulation water from and to the heating source and the heat emission points, characterized in that the system is provided with an accumulation vessel with an integrated hot tap water heating system for the use of hot tap water for sanitary purposes and kitchen use in the living space accomodations.

21. Hot water heating system according to claim 20, characterized in that the accumulation vessel is provided with at least one hot water inflow pipe for the intake in the accumulation vessel of hot circulation water from the heating source (s) , with a hot water outflow pipe for the leading away of hot circulation water from the accumulation vessel to the heat emissi- on points, with at least one cold water inflow pipe for the intake from cooled off cold circulation water from the heat emission points, and with a cold water outflow pipe for the leading away out of the accumulation vessel of cooled off cold circulation water to the heating source (s) .

22. Hot water heating system according to claim 21, characterized in that the opening of the cold water outflow pipe for the leading out of the accumulation vessel of cooled off cold circulation water to the heating source (s) is located at the bottom of the vessel.

23. Hot water heating system according to claim 21, characterized in that the opening of the hot water inflow pipe for the intake in the accumulation vessel of hot circulation water from the heating source (s) is located at the side of the vessel, above the opening of the cold water inflow pipe for the intake in the vessel of cooled off cold circulation water from the heat emission points.

24. Hot water heating system according to claim 21, characterized in that the opening of the hot water outflow pipe for the leading away of hot circulation water from out of the vessel to the heat emission points is located at the bottom of the vessel, more in particular substantially approximately in the middle of the vessel by means of the insert pipe as an extension of the hot water outflow pipe.

25. Hot water heating system according to claims 21 and

23, characterized in that the hot and cold water inflow pipes are provided with inflow constructions, which, more in particular, are formed by two perforated plates, such that the speed of the circulation water flowing through is diminished and that the turbulent flow patterns in the circulation water flowing through are transformed in laminar flow patterns.

26. Hot water heating system according to claim 25, characterized in that in the accumulation vessel at least one vertical riser and fall pipe is provided which is connected to the inflow constructions of the hot and cold water inflow pipes.

27. Hot water heating system according to claim 26, characterized in that the wall of the riser and fall pipe is provided with perforations, more in particular slit-shaped perforations.

28. Hot water heating system according to claim 25, characterized in that the riser and fall pipe is provided on the inside with a wire gauze, more in particular a fine-meshed wire gauze.

29. Hot water heating system according to claim 20, 21 and 24, characterized in that the volume of the accumulation vessel 11, at the height of the upper level of the insert pipe of the hot water outflow pipe, is divi- ded in two separate volumes functioning independantly from one another, more in particular, in a bottom and a top volume.

30. Hot water heating system according to claim 20 and 29, characterized in that in the top volume of the accumulation vessel a tap water spiral is provided for heating of cold tap water to warm and hot tap water for sanitary purposes and kitchen use in living space accomodations .

31. Hot water heating system according to claim 30, characterized in that the tap water spiral is provided with a circulation casing, more in particular a circulation shaft for generating a natural circulation flow of hot circulation water along the tap water spiral.

32. Hot water heating system according to claim 31, characterized in that the circulation casing of the circulation shaft is provided with perforations, more in particular slit-shaped perforations.

33. Hot water heating system according to one of the preceding claims, characterized in that in the accumulation vessel a layered building up is obtained of inflowing hot, warm, and cold circulation water with as a result hot circulation water in top, cooled off cold circulation water at the bottom and warm circulation water in layers in between.

34. Hot water heating system according to one of the preceding claims, characterized in that the accumulati- on vessel can also function well as solar boiler for a connected solar installation.

35. Hot water heating system according to one of the preceding claims, characterized in that in top of the accumulation vessel an expansion volume is provided for accumulating and recuperating of expansion water from out of the vessel and from out of the connected installations .

36. Hot water heating system according to one of the preceding claims, characterized in that the accumulation vessel by means of the expansion volume is the hydraulic zero point of all the connected installations, by means of which all of these installa- tions can function independantly from one another.