DE102005051663A1 - Circulatory heater for heating drinking water, has high-grade steel pipes, watered by drinking water, consists of thin-walled oval pipe with straight flanks - Google Patents

Abstract

Circulatory heater (2) has high-grade steel pipes, watered by drinking water, consists of thin-walled oval pipe with straight flanks. The flanks deforms elastic membrane shape with the recurring pressure fluctuation between the flow pressure of one bar and static pressure of ten bar and prevents formation of a lasting boiler scale at the tube wall. Independent claims are also included for the following: (1) Heating water separator; (2) Formation of heating water separator; and (3) Heating water stratified storage.

Description

In Germany, central drinking water heating systems are predominantly equipped with drinking water storage systems due to the previously assumed peak demand figures (DIN 4708). Even systems with thermal solar collectors are usually with bivalent heated storage water heaters after 7 equipped. The storage tanks have two heating surfaces and are heated up by primary energy to approx. 60 ° C and preheated in the lower storage part of solar energy to the respective possible temperature.

to Use, i. For Tap and circulation will be the outlet temperature of the store of 60 ° C over drinking water mixer for the Hot water distribution network with cold water down to 45 to 50 ° C mixed. The disadvantage of this usual Series connection with reheating to 60 ° C is guaranteed Primary energy consumption from 28% for an unnecessary one temperature increase from for example 50 ° C in preheater to 60 ° C in the reheater. (recommended minimum temperature 50 ° C for a- u. Two-family houses according to DVGW worksheet W551)

In Plants with a larger distribution network, in which the circulation can not be waived, takes one for comfort and hygiene reasons considerable heat losses for the Hot and circulation pipes in purchase. The by cooling the water Circulation losses occurring in the distribution network reduce the degree of utilization the central drinking water heating about 50%.

If the drinking water circulation line is connected as usual to bivalent solar storage tanks at the top of the tank and the connection line of the drinking water mixer to cold water, the circulation losses in the plants will be lost 7 covered almost exclusively by primary energy!

Also the heating water tank with integrated DHW cylinder after 8th has this disadvantage. Only when the solar energy is sufficient to heat the entire heating water and drinking water storage above 60 ° C, solar energy is also used to cover the circulation losses. However, experience has shown that this is only the case if, as on vacation, there is no need.

The drinking water temperature in the upper drinking water storage tank after 8th In winter, it even moves to the high level of the heating flow temperature, ie up to 85 ° C. The use of solar energy for DHW heating is about 0%. A 10 square meter collector field needed for a temperature increase of 10 K in memory over two hours! The solar heating surface is located outside the vertical baffle channel and must heat the entire volume under the drinking water storage tank to at least 60 ° C before solar heat can be used for the TWE. Otherwise, primary energy is used to heat the DHW heating system.

With the increasing use of alternative energy sources such as wood, pellets and straw, heating water storage tanks are also used instead of drinking water storage tanks. The DHW heating is integrated with memory, as in 8th or via external flow heaters or drinking water storage. For reasons of hygiene and to improve the Heizmittelauskühlung flow heater are increasingly used in the form of finned tube or plate heat exchangers

Drinking water heating systems in multi-family houses, Hotels etc. are however for hygienic reasons (legionella problem) with 60 ° C too operate (single- and two-family houses at least 50 ° C). As a result However, this mode of operation is in all drinking water areas with more as (8 ° dH) with calcification of the usual Flow heater to count.

One serious indication of this calcification risk of flow heaters is given in the new VDI guideline 6003. There are flow heaters and storage systems, depending on the design of the heat exchanger classified as "devices with increased calcification risk".

As Heizwasserspeicher various systems are used in which the supply and discharge of different temperature heating water in the container either very simple as in 8th and with adverse consequences for stratification and removal efficiency, or with high regulatory overhead, complicated and costly, as done for large scale facilities.

The it lead to, that economically usable Heizwasserschichtenspeicher the Also, with increasing domestic hot water temperatures higher requirements sufficient practically not available stand.

All known solar storage boilers and heating water storage systems for solar energy, Biofuels and alternative energy have in terms of use of primary energy a common disadvantage.

In any known solution, the upper part of the storage (ready volume) becomes like in the solar storage boiler 9 from the oil gas boiler heated with a minimum heating water temperature (standby temperature) operated, for example, "12 K on DHW temperature" is set.

at One- and two-family houses means that due to the hygiene regulations (DVGW 551) a heating water temperature of 65 ° C and at apartment buildings 75 ° C in Standby volume of the heating water storage tank.

The Standby temperature is so high because of the entern connected Flow water heater this Temperature to cover the demand peaks in the drinking water heating system needed.

The standby volume heated by the integrated oil-gas boiler via primary energy in the upper part of the solar storage boiler 9 is heated to 65 ° C. (Standby temperature in one and two-family house)

The heating water volume of the solar storage boiler, which is heated by solar energy and usually has a lower temperature level (example 55 ° C), is located in 9 below the oil-gas boiler.

With the usual removal of amounts of heating water for the external flow DHW heater at the top of Heizwasserspeicher by the series connection of the temperature-stratified Heizwasservolumina after 9 an unintentional primary energy consumption of at least 25% based on the drinking water heating capacity for the unnecessary temperature increase from 55 ° C to 65 ° C accepted. In multi-family houses, the share of primary energy is even over 33% due to the 10 K higher operating temperatures.

Of the same drawback related to the use of alternative energy arises for solar storage boilers and heating water storage tanks with standby volume and minimum heating water temperature also for the heating connected in the same way.

All in all arises from the use of solar energy for DHW heating and Heating by the described disadvantages of the known systems an unwanted primary energy consumption of 30%.

novelty

The Condensing use, the use of bio-fuels, the use of solar energy and the use of heat pumps and fuel cells for heating and drinking water heating Can be used in systems with drinking water circulation through appropriate design and Arrangement of the flow heater in the heating water tank, by introducing a innovative heating water distributor and the improved connection the consumer to the Heizwasserschichtenspeicher energetically 25-40 % be improved.

To eliminate the described calcification risk for flow heater is proposed according to claim 1 instead of plate heat exchangers and heat exchangers with finned tubes thin-walled flat-oval tubes (membrane oval tube) after 2 use.

It There are experiences, according to which the self-cleaning property such heating surfaces the occurring pressure fluctuations between approx. 1 bar flow pressure and about 10 bar static pressure is given in the drinking water.

The Tubes deform resiliently in a membrane shape whereby a permanent scale formation prevents the pipe wall becomes.

The flat-oval shape can be used for the preheater ( 5 ) in 1 easy when winding thin tubes on the Leitmantel ( 4 ) are produced by running parallel side rollers in one operation with the winding.

For the plate-shaped spirals of the Nachwärmers ( 6 ) in 1 and the heating surface for the circulation ( 11 ) is the flat oval profile after winding round tube by subsequent pressing of the spirals between two flat tools to achieve.

The Novel construction of the flow heater according to claim 1 allows the maintenance-free use in all today occurring waters and for every Type of heat generation.

By forced Heizwasserumströmung the preheating ( 5 ) between outer jacket ( 1 ) and baffle ( 4 ) are controlled by means of the speed-controlled circulating pump ( 22 ) reaches such high heat transfer coefficients that the cooling of the heating water up to the vicinity of the cold water temperature is possible. This feature in turn allows a reduction in the required heating water storage capacity, the additional use of the boiler water content, the improvement of condensation conditions for condensing boilers and the better cooling of the return water for district heating and solar collectors.

calculations have shown that in housing construction and in hotels with today's usual interpretation the boiler output for the heating heat demand and a surcharge for the drinking water heating (DIN 4708) from 1 to 1000 apartments in addition to the usual boiler water content only a small storage volume in Heizwasserspeicher required is for ale objects between 1 and 1000 apartments less than 250 liters Content).

The new requirements for DHW generators in relation to a variety of heat sources such as solar energy, condensing boilers, wood heating, heat pump, fuel cell with the special installation of the flow heater ( 2 ) in a vertical Heizwasserspeicher ( 1 ) with centrally arranged heating water distributor ( 13 ) and the arrangement of the heating surface for the circulation ( 11 ) Fulfills. 1 shows the required according to claim 2 equipment of the Heizwasserschichtenspeichers with the drinking water mixer ( 9 ), circulation ( 3 ), the variable speed heating water circulation pump ( 22 ) and the connection of alternative heat energy sources to the flow ( 17 ) and the return ( 21 ).

The speed of the pump ( 22 ) is dependent on the temperature after the preheater in the connection ( 7 ) at the measuring point ( 27 ) controlled. At the measuring point ( 27 ) in circulation mode, the outlet temperature of the circulation water after the heating surface ( 11 ) detected. If the temperature increase is sufficient, the pipeline network ( 10 ) with water from the connection ( 7 ) provided. For example, in the case of alternative heating with solar energy, with the solar flow connected to the connection ( 17 ) and solar return connected to connection ( 21 ) at a slightly higher temperature of the solar flow compared to the circulation drinking water, the circulation heat losses to 100% covered with solar energy.

The selected according to claim 3 arrangement of preheater ( 5 ), Reheater ( 6 ) and the heating surface for the circulation ( 11 ) in conjunction with the separating plate ( 4 ) allows, for example, the use of solar energy for one- and two-family houses in three temperature levels. Stage 1 from 10 to 45 ° C with the preheater ( 5 ), Level 2 of 45-50 ° C for the circulation on the heating surface ( 11 ) and stage 3 from 50 ° C to 55 ° C for reheating to 55 ° C at the reheater ( 6 ).

The prerequisite for the described stepwise heating of the flow heater with solar energy, however, is the self-regulating layer-forming supply line of the solar flow ( 17 ) so that, depending on the respective temperature of the solar flow water and the respective temperature zone in the container, the solar heat supply is optimal and at the right height.

According to claim 4, this problem is for both the incoming solar supply water ( 17 ) at the top of the container as well as for the incoming return water ( 18 ) at the bottom of the tank through the heating water distributor ( 12 ) in conjunction with the baffle ( 13 ) solved. 3 shows the cross section through the double-spiral for heating water, which by winding a simple cheap rectangular sheet on the central tube ( 12 ) with the slot ( 14 ).

In 4 is the one possible distribution of at ( 17 ) and ( 18 ) entering Heizwassermengen represented by flow arrows. The flow rate of the heating water is determined by the inlet ( 17 ) or ( 18 ) via the double spiral ( 13 ) is reduced by the factor 60 on the rectangular outlet cross-section into the container so that the desired temperature-stratified true distribution of the inflowing heating water is self-regulating, using the physical properties of the heated water in a colder or warmer container environment. Cold water is distributed downwards, warm water rises on the way up through the spiral. Negative effects of the temperature difference between the water in the pipe ( 12 ) and the water in the container ( 1 ) (Temperature compensation) are due to the insulating effect of the multi-start spiral 13 prevented. (low heat transfer through several walls and layers of water at laminar flow).

In the manner described above, according to claim 4 and 5 by a single component not only the forced consumption of primary energy as shown in Figure 1 and 2 avoided, but at the same time the thermal efficiency of the solar panels is improved. The improvement of the thermal efficiency for the collectors results from a considerable increase of the removal quantities from the solar-heated preheating ( 5 ) (better cooling, better use).

The heating of the stratified storage ( 1 ) from the boiler via the boiler flow at the connection ( 15 ). The speed-controlled heating water pump ( 22 ) is in the boiler return ( 16 ), for example in conjunction with a spring-loaded overflow valve ( 26 ) installed in such a way that all normal drinking water taps can be covered by the heat content of the heating water storage tank. In this case, the return water flows from the connection ( 16 ) via the pump ( 22 ) to the connection ( 18 ) and via the heating water distributor ( 12 ) and the lower part of the baffle ( 13 ) self-regulating temperature-layered back into the container.

Only with top taps and then, if the, in the container ( 1 ) stored amount of heat is no longer sufficient to cover the tap capacity increases the speed of the circulating pump ( 22 ), controlled by the temperature sensor ( 27 ), so high that the required differential pressure to open the spring-loaded spill valve ( 26 ) is exceeded and the container via the flow ( 15 ) is heated by the heat generator.

For large drinking water heating systems with more than 3 liters of pipe capacity, the DVGW worksheet W 551 for the hot water distribution network ( 10 ) 60 ° C required. This high drinking water temperature is not reached by all heat pump types. For this reason, the installation of an electric immersion heater ( 24 ) above the heating surface for the circulation ( 11 ) intended. This makes it possible to connect the heat pump flow to the connection ( 17 ) the preheating of the drinking water via the preheater ( 5 ) and the heating surface ( 11 ) of, for example, 10 ° C to 50 ° C with the heat pump and the reheating to 60-70 ° C via the reheater ( 6 ) with the help of the electric heating cartridge.

The novel heating water distributor with the components ( 12 ), and ( 13 ) is just as advantageous as in the previously described drinking water heater with Heizwasserspeicherung also used in pure Heizwasserschichtenspeichern after 5 , In order to be able to connect for larger objects also several heat sources and several consumers here according to claim 7, the central tube ( 12 ) by installing two additional dividers ( 28 ) and ( 29 ) and the two closure sheets ( 45 ) and ( 46 ) equipped. By the cultivation of 4 connections ( 30 ) 31 ) 32 ) and ( 34 ), two separately usable heating water distribution systems are created, for example for solar energy ( 43 ) and ( 44 ) and heat pump ( 35 ), can be used.

The usual connection of the primary energy heated boiler ( 42 ) at the connections ( 47 ) and ( 48 ) with the standby temperature of about 75 ° C in the upper tank has the disadvantage in all known heating water storage systems that by the series connection of preheated and nachwärärmem (minimum temperature for readiness) Heizwasservolumen when supplying the consumer heating ( 36 ) and drinking water heating ( 37 ) over the usual connecting piece ( 38 ) an unwanted consumption of primary energy arises.

Example: In large plants, to cover the circulation losses at the DHW cylinder ( 37 ) requires a heating water inlet temperature of approx. 63 ° C. The return temperature is approx. 58 ° C. With the usual heating water storage tanks, even if the solar flow temperature at the connection ( 30 ) above 63 ° C by using the, at 75 ° C overheated heating water at the top of the container only primary energy to cover the circulation losses consumed.

Only when more than 75 ° C in the solar circuit ( 30 ) are offered, with conventional systems, the coverage of the circulation losses with solar energy is possible.

In order to eliminate this disadvantage, according to claim 8 proposed Heizwasserschichtenspeicher with an additional connecting piece ( 39 ) just below the return pipe ( 47 ) for the boiler ( 42 ) and the heat consumer heating ( 36 ) and drinking water heating ( 37 ) via a conventional 3-way mixer ( 40 ) to the connecting pieces ( 38 ) and ( 39 ) so that at a sufficiently high temperature at the neck ( 39 ) automatically both systems ( 36 and 37 ) are supplied with heating water from this connection, without the boiler ( 42 ) or the E-cartridge ( 43 ) higher heated Heizwasservolumen in the upper part of Heizwasserspeichers to complete.

In the manner described above, not only the compulsory consumption of primary energy described for known systems is avoided, but at the same time the thermal efficiency for the solar collectors is lowered by lowering the temperature in the collector ( 49 ) improved. The expected improvement in the efficiency of DHW heating in the summer is around 25% for solar systems with heating water layer storage

The same benefits arise from the proposed connection ( 39 ) in connection with the mixer ( 40 ) even if as alternative heat generators ( 35 ) Heat pumps, fuel cells or CHP are operated whose flow temperature is limited. For example, with a heat pump suitable for a maximum of 60 ° C flow temperature, up to which heating flow temperature of 60 ° C behind the mixer ( 40 ), on the thermal heat of the above in the memory additionally installed e-cartridge ( 43 ) completely omitted. The heat content of the heating water above the E-cartridge ( 43 ) is only used for demand temperatures exceeding 60 ° C. The standby volume above the E cartridge ( 43 ) can now be heated without disadvantages up to 95 ° C (higher heat storage and longer burner run times on the boiler ( 42 )).

6 shows a so-called solar storage boiler with a, in the Heizwasserspeicher integrated condensing boiler ( 54 ). The solar storage boiler is both with the proposed according to claim 1 and 2 flow heater ( 2 ) as well as with a heating water distributor ( 12 ) according to claim 4 with guide plate ( 13 ) as well as with the Dreiwe mixed ( 40 ), which according to claim 8 for avoiding unnecessary primary energy consumption to the terminal ( 39 ) is connected so that at sufficient temperature at the port ( 39 ) the heating is fed exclusively or at not quite sufficient temperature partially with amounts of heating water from this connection piece. The heating water distributor with guide plate ( 13 ) and the separating plates ( 28 ) has two ways according to claim 5 and is provided with a way for the distribution of the heating return and the second way for the distribution of, from the solar circuit on the finned tube heating surface ( 56 ) heated heating water between the lower floor ( 16 ) and a baffle ( 57 ) used.

According to claim 9 of the heating water distributor ( 12 ) with a large entrance opening ( 55 ) into which the solar heating surface ( 56 ) heated heating water enters, so that the distribution of differently heated heating water from the space between floor ( 16 ) and baffle ( 57 ) is achieved with the described advantages for the temperature stratification in the container for the case of the integrated solar heating without additional circulation pump (gravity heating).

Claims (9)

Flow heater ( 2 ) for DHW heating 1 characterized in that the water flowing through the stainless steel tubes made of thin-walled oval tube with straight flanks after 2 exist, which deform resiliently in the pressure fluctuations occurring between 1 bar flow pressure and 10 bar static pressure and prevent permanent scale formation on the pipe wall. Flow heater ( 2 ) according to claim 1, characterized in that it consists of a preheater ( 5 ) and a reheater ( 6 ) whose withdrawals ( 7 ) and ( 8th ) on a mixer ( 9 ) are guided so that with sufficient outlet temperature of the preheater at the connection ( 7 ) the total power for the distribution network ( 10 ) alone from the preheater ( 5 ) is provided. Flow heater ( 2 ) according to claim 1 and 2 for systems with circulation ( 3 ) and drinking water mixer ( 9 ), characterized in that for reheating the circulation losses a predominantly horizontal part of the flow heater ( 11 ) between preheaters ( 5 ) and reheater ( 6 ) is arranged so that a centrally supplied Heizwassermenge with slightly higher temperature than that of the drinking water in the circulation ( 3 ) can take over the heating of the circulation water. Heating water distributor after 3 characterized in that for the distribution of heating water of different temperature and quantity a single simple component, the spirally wound baffle ( 13 ) is used to reduce the rate of entry of the heating water into the container, to prevent the temperature compensation to the contents of the container through several walls and layers of water and thus the temperature stratified supply of heating water without disturbing the existing temperature stratification in the container caused by the use of simple physical laws. Heating water distributor according to claim 4, characterized in that after 4 the spiral ( 13 ) below for the amount of water from the connection ( 18 ) to the end plate ( 20 ) in both ways and up to the end plate ( 19 ) is used with a path while the double-flighted spiral ( 13 ) above for the amount of water from the connection ( 17 ) to the end plate ( 19 ) in both ways and up to the end plate ( 20 ) is used with a way, so that the. Connections ( 17 ) and ( 18 ) can be used with the same advantages for layering in the container. Formation Heizwasserverteilers according to claim 4 and 5, characterized in that the central tubes ( 12 ) with slot ( 14 ) and the end plates ( 19 ) and ( 20 ) at the same time as a tool for winding the baffle ( 13 ), as a pipe anchor between the upper floor ( 15 ) and lower ground ( 16 ) and with the inserted pipe ends ( 17 ) and ( 18 ) is used as connection for heating water inlet and outlet. Heizwasserschichtenspeicher after 5 with Heizwasserverteiler according to claim 4, 5 and 6, characterized in that by installation of two additional separating plates ( 28 ) and ( 29 ) in the central tube ( 12 ) and the installation of 4 connections ( 30 ) to ( 34 ), two separately usable distribution systems are emerging, for example, for solar energy ( 43 and 44 ) and heat pump ( 35 ), can be used. Heizwasserschichtenspeicher after 5 with Heizwasserverteiler according to claim 4, 5, 6 characterized in that the heat consumer heating ( 36 ) and drinking water heating ( 37 ) individually or together over the mixer ( 40 ) to the connecting pieces ( 38 ) and ( 39 ) are connected so that at a sufficiently high temperature at the neck ( 39 ), both systems are automatically supplied with heating water quantities from this connection, without that from the boiler ( 42 ) or the E-cartridge ( 43 ) higher heated Heizwasservolumen in the upper part of Heizwasserspeichers to complete. Heizwasserschichtenspeicher or solar storage boiler after 6 with flow heater ( 2 ) according to claim 1, 2, 3 and Heizwasserverteiler after Claim 4, 5, 6, 7 and connection of the heat consumer according to claim 8, characterized in that a heating surface ( 56 ) with guide plate ( 57 ) is arranged so that the Heizwasserverteiler is designed according to claim 7 in one of the two ways to gravity conditions and the temperature-layered distribution of, for example, heated by solar energy heating water is used.