DE3019198A1 - Central heating system assisted by district heating - uses remote controlled additional heat supply for full or partial heating at given times - Google Patents

Abstract

The central heating system for a household uses an internal central heating circuit which can also be combined with a district heating system. The remote heating source may be a power station with excess capacity available only at certain times. This can be connected so as to supply all or part of the heat required for the household. The changeover between the two alternative systems can be operated by remote control from a remote central station. Groups of buildings can be changed over at different times. Hot water from the remote supply can be used for room heating and also other purposes. Different circuits are used for direct and indirect connection for these purposes. One circuit includes cutting off or throttling members in the supply line.

Description

PATE N TA N SELECTION D-I BERLIN-DAHLEM 33 POD3IELSKIALLEE ββ D-θ MUNICH 22 WIDENMAYERSTRASSE 49

Günter Neumann

BERLIN! DIPL.-ING. R. MÜLLER-BORNER

MUNICH: DIPL.-INQ. HANS-HEINRICH WEY DIPL.-INQ. EKKEHARD KORNER

Berlin, May 16, 1989

Process for better utilization of district heating systems with combined heat and power

13 pages of description with. 6 claims 3 sheets of drawings

MP - 27 585

130048/0302

BERLIN .: TELEPHONE (03O) 8 31 2Ο88 CABLE: PROPINDUS TELEX OI 84Ο67 MUNICH: TELEPHONE (089) 2S668S CABLE: PROPlN DUS ■ TELEX O624244

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The invention relates to a method for better utilization of district heating systems with combined heat and power for the heat supply of buildings. Such heating systems are in a special way the requirements of Combined heat and power in the steam power plant adapted, with the transport of large amounts of heat under the streets of the City to the home stations of the customers.

In addition to the traditional two-wire system, consisting of from forward and reverse, the use of e.ines is also possible Three-wire system common. In the case of the latter, a head is used to supply the heat consumers throughout the year Use predominantly constant water temperatures for domestic water heating and for ventilation systems. The second Ladder is used exclusively for heating buildings used, the temperatures in this sliding ladder - centrally controlled by the power stations are adapted to the respective outside temperatures. The third conductor returns the common return water to the power plant (cf. ■ Bublitζ "City heating through combined heat and power · Coupling in Berlin "in the magazine Fernwärme International 4, pages 98-106). ■ -

The invention is based on the object of providing a sufficient To ensure that buildings are supplied with heat by district heating systems, even if they are fully heated Buildings with district heating is no longer possible because either the district heating network, the thermal power station or both are too critical Times are fully utilized.

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The invention provides for bivalent heating (internal or district heating supply) for these buildings. Included the switchover from one type of heat supply to the other is carried out centrally by a ripple control system, so that these buildings are only supplied with district heating when the district heating system has free capacity. In these When there is free capacity, the supplied heat can be withdrawn from the consumer in a regulated manner and, if necessary can also be stored in order to enable heating in the critical bottleneck times in which no heat is supplied. If the stored heat is insufficient for these critical times or if storage is dispensed with, the additional heating is carried out by the boiler installed at the consumer. The necessary during bottlenecks in the district heating system The ripple control system can switch off buildings with bivalent heating from the district heating supply take place that several shutdown groups are formed, which can be switched at different times. By Appropriate selection of the groups to be switched can, approximately the same supply times from the district heating network for all shutdown groups are aimed for.

The invention can be used in all district heating systems, especially with combined heat and power be applied. The only prerequisite are temporary, free capacities for heat generation in the thermal power station and for de / i transport in the district heating network. at The district heating networks can be heating steam or heating water networks. Heating water networks can use two-wire (pre- and Return) and three-wire networks (two separate forwards and one common return). In the case of three-wire networks

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the method is mainly suitable for the leader who with constant flow temperature and fluctuating hydraulic load is operated by local regulation at the customer. If the System uses a ladder with a sliding flow temperature and constant hydraulic load, then this is suitable Head only if there is free transport capacity for district heating in this network conductor. In general Are these free capacities available through design reserves or can they be planned for during construction? will.

With the invention, a better utilization of the district heating systems in both ^; Cogeneration plant as well as in the distribution area (network). The greater supply of heat from the combined heat and power unit, which is associated with higher utilization, leads to fuel savings. For the bivalent-heated buildings, to greater economic benefit and better environmental protection as a result of fuel savings, higher chimneys, better technical equipment and stricter monitoring in the thermal power stations. The invention can also be used for premature partial district heating of the buildings until the completion of additional thermal power stations for full heating, provided that there is free capacity.

The connection of a generally existing heating system to a district heating network for bivalent supply is shown below using only three selected examples described because the variety of district heating and house heating systems does not allow a uniform connection circuit. Reason-

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In addition, heating systems can directly or indirectly via heat exchangers to the district heating networks for bivalent Supply. To be connected. Because of the greater importance of hot water heating systems today, these are only connection examples from this area shown in the drawings. Figures 1, 2 and 3 show connection circuits for heating systems for bivalent supply to district heating water networks, namely Fig. 1 the direct connection of a hot water heating system for space heating and special consumers (hot water preparation, ventilation and air conditioning systems); Fig. 2 the indirect connection a hot water heater for space heating and special consumers; and Fig. 3 direct connections of hot water heating systems with the possibility of barriers or throttling of the heating water flow to the consumers for space heating and special consumers in advance.

The system to be connected, thinly drawn in Figure 1 and marked with numbers from 0.10 to 0.21, exists in the boiler area from the heating boiler 0.10, the boiler pump 0.14 and a boiler mixing valve 0.21 to avoid. Too low boiler inlet temperatures. The heat consumers are used by the radiators of the room heating 0.15 and the special consumers 0.16 (hot water preparation, ventilation, air conditioning units) shown. The heat supply of these consumers is for the room heating through aas control valve 0.11 with the sensors 0.20 (outside temperature) and 0.18 (flow temperature) in connection with the circulation pump 0.13 and the mixing line (Non-return valve) 0.17 regulated. For each special consumption group (e.g. the central hot water storage tank or air heater)

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is the heat supply through a control valve O.12 with the Sensor 0.19 regulated. "

The minimal change in the heating system through the direct. District heating connection is shown thick on picture 1 and through the. Numbers 1.1 to 1.7. In the flow line, which is to be connected to the district heating flow, is a shut-off device 1.1, a pressure reducer. 1.2, -a safety valve 1.3 and a temperature sensor 1.7 installed. In the return, which is connected to the return of the district heating network, there is a shut-off device with motor drive 1.6. and connection to the ripple control system, a measuring and power limiting device .1.5 to install a non-return valve 1.4 in the return of the house system for billing purposes.

If necessary, a heat storage tank 2.1 can also be installed - shown in Fig. 1 with a medium thickness and marked "with numbers from 2.1 to 2.4 - which works according to the displacement principle of the control valves is controlled 0.11 to 00:12, controls the charging process. the return of connectable heating system is interrupted by the blind flange. the boiler pump Q.Xk of connectable heating system receives a switching device which operates in dependence on the position of the obturator 1.6.

The heating system to be connected is supplied either by the boiler 0.10 or the district heating network guaranteed. The heat is then supplied in the boiler,

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if a specified water temperature in the boiler is fallen below. On a central command from the Pernheiz operator via the ripple control system, the Shut-off element .1.6 are opened so that heating water from the flow of the district heating network through the fittings and 1.2 the return before the boiler enters the heating system to be connected and after passing through the heating system and emitting heat to consumers 0.15 and 0.16 through 1.5 and 1.6 in the Return of the district heating network flows out again. The non-return valve 1..A prevents delivery from the district heating network bypassing the heating system in a short circuit.

In addition to this type of connection, the flow of the district heating connection could from 1.2 behind the boiler outlet (0.10). This alternative would then be useful if boiler operation can be dispensed with for a longer period of time. This measure would have the advantage that at boiler losses can be avoided when the boiler is switched off. It would be disadvantageous if the boiler was not switched off and district heating, keeping the boiler warm by the Firing (increased fuel consumption).

Due to the inflow of sufficiently warm heating water into the Boiler, the heat supply is cut off by the furnace or restricted. The heating water flowing through the boiler is fed to the consumers. The inflow amount is regulated by the control valves 0.11 and 0.12. In the Room heating is the flow temperature - measured by 0.18 - via the mixing flap 0.17 by a Outside temperature-dependent (0.20) setpoint specification regulated. Such a regulation can also be used as a preliminary regulation for others

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Special consumers make sense. The heat output held by the district heating network, which may be used by the house system, "is limited by the district heating operator via device 1.5 by throttling the flow of heating water supplied. This device also serves to ¹ ; record the heat supplied. '_ ■ -" · '.

The heat supply is also interrupted by a central command from the heating operator, in which the valve 1.6 is closed again. Mach closed valve 1.6. pump 0.14 is automatically switched on again. The heat demand is covered by boiler 0.10, the return water from the consumer flows to the boiler via flap 1.4 and heating water flows into the return of the heating system via mixing valve 0.21 to raise the boiler inlet temperature. If the boiler operation is also to be restricted during the times when there is no heat supply from the district heating network, it is possible to operate the storage system 2.1. The part of the delivery capacity contractually agreed by the district heating operator (measured and limited by 1.5) not used by consumers 0 * 15 and 0.16 can be used as charging capacity in storage tank 2.1. Heating water flows from the flow of the district heating network from above into the displacement storage tank 2.!, There displaces colder return water, which _{leaves the storage tank via 2 ". 3 3 of} the measuring station 1.5 and the open shut-off valve 1.6 into the return of the district heating network.

This heating water flow is limited by the control valve 2.3 · If the heat supply to the consumer is 0.15 and O.16 disturbed by the memory loading (full opening of the

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Control valves 0.11 or 0.12), valve 2.3 is throttled. This valve 2.3 is completely closed when the temperature, measured by 2.2, exceeds a limit value, i.e. when the memory is loaded.

If the district heating operator has interrupted the heat supply by closing 1.6, the heat supply in the boiler can be restricted by allowing the return water of the heating system over. 1. ¹ I (the 'return is interrupted by 2. 4) flows from below into the storage tank 2.1 and the charged warmer flow water pushes upwards out of the storage tank, which then flows over 0.14 to the boiler 0.10. The boiler then only has to provide the missing residual heat output through additional firing. In extreme cases, if there is sufficient stored heat, the boiler may not operate at all. Even when the storage tank 2.1 is discharged, the system is operated hydraulically in the same way as during the described discharging process of the storage tank. .

The heating system to be connected indirectly - shown thinly in Figure 2 and marked with numbers from 0.11 to 0.22 - differs from the system, which is described in Figure 1, essentially only in a different one, Very common, outside temperature-dependent control of the flow temperature 0.1.8 via a four-way mixing valve il 0.11. In addition, a separate circulation pump is used for special consumers 0.16. In contrast, the boiler pump 0.14 is missing as well as the boiler mixing valve 0.21. Otherwise, all have names compared to the arrangement in Fig! the same meaning, the minimum required additional units for the heat delivery from the district heating network (thick on picture 2 and identified by numbers 1.1 to 1.91) differ significantly from the arrangement in Fig. lim by the additional heat exchanger 1.8, the return

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flow temperature limiter 1.9 "with temperature sensor 1.91 ■ and the absence of the non-return valve 1Λ. All units not mentioned here have the same task in Figure 2 as in Figure 1. If the strength design of the heat exchanger allows it, fittings 1.2 and can be dispensed with Thermal storage tanks are / are installed to further restrict boiler operation (shown in "Fig. 2, medium-thick and identified by numbers from 2.1 to 2.5), the storage tank discharge pump 2.5 with temperature sensors 2.k and 2.6 must be installed in addition to the units described in Fig. 1. ■ Alternatively, the storage unit could also be installed on the secondary side of the heat transfer (consumer side).

The heating system to be connected works in principle like the above-described system in Figure 1, except that the flow temperature of the room heating is controlled by a four-way mixing valve O.il with an outside temperature-dependent setpoint, while the return to boiler 0.10 is routed via this mixing valve at the same time. At the same time, the return is heated up by mixing the flow water from the boiler 0.10. The minimum necessary measures for connecting this heating system to a Fernheizne.tz - drawn in bold in Figure 2 and marked with numbers from 1.1 to 1.91 - have, so far. previously described, same function. The additional heat exchanger is intended to separate the heat carrier of the district heating from that of the heating system. The reason could be, for example _, a different pressure rating for the heating system. The temperature limiter 1.9 with temperature sensor 1.91 is intended to prevent consumer 0.15 and 0.16

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the heating water from the district heating network leaves the heat exchanger 1.8 with too little cooling. If the temperature is too high 1.91, the control valve 1.9 is throttled. The accumulator charging operation runs, as described above, with the units 2.1, 2.2. And 2.3. If the passage through the four-way mixing valve from the boiler flow to the suction side of the circulation pump 0.13 is fully open, the valve 2.3 is throttled here, as described above. When the valve 1.6 is closed by the district heating operator, valve 2.3 opens automatically and the storage tank discharge pump 2.5 starts to work. This pump pushes return water from below through the open valve 2.3 into the memory 2.1. As a result, any warmer heating water in the storage tank is pressed into the heat exchanger 1.8 and can there give off heat to the return water of the heating system flowing through the apparatus on the secondary side. The discharge operation is ended by switching off the pump 2.5 when the temperature 2.U at the upper end of the storage tank is sufficiently low compared to the temperature 2.6 of the return water to be heated (discharge criterion).

The type of circuit shown in Figure 3 for heating systems to be connected could harbor the risk of heating water flowing from high-lying parts of the system into the return line (draining) and causing malfunctions. This risk can be countered by installing an overflow valve I.6I in front of the shut-off element 1.6 in 'Figure 3 -'

With this type of connection there are also changes in the heating system compared to Fig. 2 the non- return valves ΙΛ, 1.4l and 1.411 in the boiler circuit and in the return of the special

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consumer provided. All other aggregates have same meaning as in the arrangements according to the picture! and Fig. 2. ■

The function of the circuit according to Figure 3 is similar to the Arrangement, according to Fig. 2. As a deviation, the "non-return valve "1.4 are considered, which in district heating operation, bypassing the boiler with flow water. should prevent as well as the non-return valve 1.41, -. the at Fernhe is supply is closed and opened when the boiler is supplied. The non-return valve -1.411 should bypass the non-return valve 0.17 when the heating system is self-supplied by: Prevent the return water from the room heating over 1.4l. The overflow valve 1.6l "guaranteed by throttling or close a sufficient "pressure in the heating system. The functional connection of the control valve 2.3 to the valve 1.6 (2.3 closes when 1.6 closed) has the same function as the non-return valve ■ 1.411. -

MBi / MP - 27 585

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BATH ORIGINAL

Claims (6)

P a t en t a η .s .ρ .r ü, α he /1.j Method for better utilization of district heating systems with combined heat and power for the heat supply of buildings, dad · u ν ch characterized that the buildings are bivalent, that is, wholly or partially heated by district heating, with the supply of district heating for buildings with Self-sufficiency ■ is only possible when the district heating system has free capacity. 2. The method according to claim 1, characterized in ζ e i c h η e t that switching from one to . the other type of supply through a ripple control system is carried out centrally. 3 · Method according to claim 1, and 2, d a d u r c h g e k e η η ζ ei c h η e t that switching or switching off the buildings in groups at different times is carried out. . . 4. The method according to any one of claims 1 to 3, g e k e η η ζ e i c h η e t through direct connection of Hot water heating for space heating and special consumers (Fig. 1). ■ 5 «Method according to one of claims 1 to 3, g e k e η η ζ e i.c h η e t through indirect connection of Hot water heating for space heating and special consumers (Fig. 2). 130048/0302 6. The method according to any one of claims 1 to 5, ge k en η is characterized by direct connections of hot water heating systems, with shut-off or throttling .des Heizwasserstroms are carried out in the flow '■■■ /.- (Figure J). · MB '/ MP - 27 585 * - 3 - 130048/0302