RU2464499C2 - Water heating system - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: on branches from a supply heat manifold to subsystems of heating there are control valves installed, which are controlled by temperature controllers with temperature sensors on supply and return pipelines of local heating subsystems. A recuperative heat exchanger at the heating side is equipped with a bypass pipeline with a control three-way valve installed on it and controlled by a temperature controller with temperature sensors. In order to use a water heating system as single-pipe and double-pipe heating systems are connected to the heat manifolds operating with temperature curves of 140-70°C, 150-70°C and higher, a return pipeline of a heating subsystem connected directly to an outlet nozzle of the recuperative heat exchanger at the cooling side, is connected to an inlet nozzle of the recuperative heat exchanger at the heating side via supply and return pipelines of one or several heating subsystems, directly connected to a supply heat manifold via control valves controlled by temperature controllers with sensors at supply and return pipelines of these heating subsystems.

EFFECT: higher efficiency of operation of heating subsystems connected to a supply heat manifold via a recuperative heat exchanger due to automatic control of temperature and hydraulic modes of operation of heating subsystems.

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Description

The water heating system is intended for use in district heating systems.

The closest technical solution to the invention is a water heating system containing a supply and return heating mains, supply and return pipelines of local heating subsystems, a supply piping with branches, a regenerative heat exchanger with inputs and outputs on the sides of heating and cooling, heating subsystems parallel to the supply heating main through the feed pipe [1].

The disadvantage of this system is that it cannot maintain the required temperature and hydraulic modes of operation of the heating subsystems that are directly connected to the outlet pipes of the regenerative heat exchanger during the entire heating season, since the regenerative heat exchanger will work with variable heat output and temperature during different periods of the heating season modes. As a result, a recuperative heat exchanger with a heating surface selected for operation under any design conditions, under other conditions, will have either an excess heating surface or insufficient. In addition, in the closest system there is no regulation of the flow rate of makeup water supplied to the heating subsystems directly from the supply heating main, which is necessary to maintain the standard temperature values in their supply and return pipelines.

The disadvantage of the system [1] is that it cannot be used to connect two-pipe heating systems during operation of heating mains according to temperature schedules above 120-70 ° C and for single-pipe heating systems when operating heating mains according to temperature schedules above 140-70 ° C.

The aim of the invention is:

1. - improving the efficiency of the heating subsystems connected to the supply heating main through a recuperative heat exchanger and heating subsystems directly connected to the supply heating main;

2. - expanding the scope of the system when operating heating networks with temperature schedules above 140-70 ° C for single-pipe heating systems and for two-pipe heating systems when operating heating networks with temperature schedules above 120 ° C.

1. The first goal is achieved by the fact that the water heating system (Fig. 1), comprising a supply 1 and a return 2 heating mains, a supply 3 and a return 4 pipelines of local heating subsystems 5, 6, 7, 8, feed pipelines 9, a regenerative heat exchanger 10 with inputs 11, 12 and outputs 13, 14 on the sides of heating and cooling, heating subsystems 7 and 8, connected in parallel to the heating supply 1 through the supply pipes 9, equipped with control valves 15, 16, 17 installed on the supply pipes 9, controlled by temperature controllers 18, 19 and 20 with temperature sensors (DТ) on the supply 3 and return 4 pipelines of local heating subsystems 5, 6, 7, 8, and a regenerative heat exchanger 10 for the ability to control the temperature conditions of the heating subsystems 5 and 6, directly connected to its outlet pipes 13 and 14, is equipped with a bypass pipe 21 on the heating side with a three-way control valve 22 mounted on it, controlled by a temperature controller 23 with temperature sensors (Dt) on the supply 3 and return 4 pipes rovodah said heating subsystem (5 and 6). This makes it possible to optimize the temperature regime of the heating subsystems (5 and 6). For example, during the operation of the system (Fig. 1) on various facades of buildings and in cases where heat-consuming installations work with different temperature schedules.

2. In order to be able to use a heating system with a recuperative heat exchanger according to claim 1 for connecting single-pipe and two-pipe heating systems to heating mains operating with temperature schedules of 140-70 ° C ÷ 150-70 ° C and above, the return pipe of the heating subsystem 5, connected directly to the outlet pipe of the recuperative heat exchanger 10 on the cooling side is connected to the inlet pipe 13 of the recuperative heat exchanger 10 on the heating side through one supply 3 and return 4 pipelines (Fig. 2, item 6) or several b (fig. 3, pos. 6, 6.1) additional heating subsystems directly connected to the heating supply 1 through control valves (fig. 2, pos. 17 and fig. 3, pos. 17, 17.1), controlled by temperature regulators (fig. 2 pos.20 and Fig.3 pos.20, 20.1) with temperature sensors on the supply 3 and return 4 pipelines of the heating subsystems (Fig.2 pos.6 and Fig.3 pos.6, 6.1). As a result, in the schemes (FIG. 2 and FIG. 3), it is possible to increase the flow of water through the regenerative heat exchanger on the heating side, i.e. cooling water to the required values when using systems (Fig. 2 and Fig. 3) for connecting both single-pipe and two-pipe heating systems to heating mains that work with almost any temperature graphs, including the one most widely used in modern centralized systems heat supply schedule of 150-70 ° C. Calculations show that when connecting single-pipe heating systems when connecting to heating mains operating with temperature schedules of 150-70 ° C, it is enough to supplement the circuit (Fig. 1) with one additional heating subsystem (Fig. 2, pos. 6), and to connect two-pipe heating systems - two additional subsystems (Fig.3 pos.6, 6.1). In some cases, the necessary ratio of costs on the sides of cooling and heating of the regenerative heat exchanger can be maintained by using a bypass pipe 21 with a three-way control valve 22.

Moreover, the flow rate of the coolant supplied to the heating subsystem through the control valves can be carried out by temperature regulators according to the water temperature in the supply pipes of the heating subsystems with a correction for the water temperature in the return pipes of the heating subsystems or with a correction for the air temperature in the heated rooms, depending on the outdoor temperature air, and depending on the temperature of the coolant in the heat supply pipe.

The water heating system (figure 2) works as follows. Hot network water from the supply pipe 1 of the heating network enters the feed pipes 9 through the control valves 15, 16 and 17 installed on them with temperature controllers 18, 19 and 20, respectively. In this case, the network water first enters the regenerative heat exchanger 10 through the control valve 15, where during the billing period it is cooled to a temperature of 95 ° C for two-pipe systems, and to 105 ° C for single-pipe heating systems, and then it enters the supply pipe 3 of the heating subsystem 5, from which it is fed through the return pipe 4 flow into the supply pipe 3 of the heating subsystem 6 together with the water mixed with it from the feed pipe 9, the amount of which is regulated by a valve 17 controlled by a temperature controller 20 that maintains the temperature of the water in the supply pipe 3 of the heating subsystem 6 according to a predetermined temperature schedule depending on the outdoor temperature or water temperature in the heating supply line, measured using temperature sensors Dt, with correction for the temperature of the water in the return pipe 4 or for the temperature during spirit in the heated rooms.

Accordingly, in the supply pipe 3 of the subsystem 6 and the recuperative heat exchanger 10, the water flow enters along the heating side (during operation of the heating system according to the schedule of 150-70 ° C and heating subsystems according to the schedule of 105-70 ° C) is 1.78 times more than the water consumption, passed through the control valve 15 and the recuperative heat exchanger 10 on the cooling side. The latter allows you to cool the network water in the recuperative heat exchanger 10 from 150 to 105 ° C and, accordingly, heat the return water after subsystem 6 from 70 to 105 ° C with a partial passage of return water from subsystem 6 through the three-way valve 22 and the bypass pipe 21 of the regenerative heater 10. Moreover in the case considered, the relative thermal power of the heating subsystems 6 and 7 should be 1.78 times greater than the power of the subsystem 5, and the power of the subsystem 8 should be respectively 1.78 times higher than the power of the heating subsystems 6 and 7 and whether in relation to the power of subsystem 5 by 3.16 times, since the flow rate of the mixed water through valves 16 and 17 at the indicated schedules of 150-70 ° C in the primary heating system and 105-70 ° C in heating subsystems 5, 6, 7, 8 is a value equal to 0.78 of the water flow in the return pipelines of the heating subsystems 5 and 7. When operating the heating mains according to the temperature schedule of 150-70 ° C, and local subsystems according to the schedule of 95-70 ° C, it is necessary to supplement the circulation loop of the heating subsystems 5 and 6 with the subsystem 6.1 to the inlet pipe 12 of the recuperative heat exchanger 10 (Fig.3).

In the latter case, the flow rate of water entering the recuperative heat exchanger 10 on the heating side will be 2.1 times greater than the flow rate of water flowing from the supply heating main to the recuperative heat exchanger 10 on the cooling side through valve 15, since in this case the flow rate in the supply pipe of subsystem 6 water will increase by 1.45 times compared to the flow rate in subsystem 5, and in subsystems 6.1 and 7, the water flow will increase by 1.45 times compared to the water flow rate in subsystem 6. Accordingly, the water flow in subsystem 8 will also increase by 1.45 times n compared with the water flow in the heating subsystems 6.1 and 7. In this case, the primary network water is cooled in the recuperative heat exchanger from 150 ° C to 95 ° C, and the return water after the subsystems 5, 6, 6.1 is heated from 70 ° C to 96 ° C.

Thus, in the thermal circuit (Fig. 3), the required temperature and hydraulic modes of operation of all the heating subsystems connected to the primary heating network are practically achieved while observing the exact distribution of thermal loads between them in the following percentage of the total thermal load:

- Subsystem 5 -10.3%

- Subsystem 6 - 14.5%

- Subsystems 6.1 and 7 - 21.6% each

- Subsystem 8 - 32.0%

In general, the number of subsystems connected to the heating system and their thermal loads are determined by calculation in each case, depending on the temperature schedule of the heating networks and local heating systems.

In the above thermal circuits (FIGS. 1, 2 and 3), the last heating subsystems (respectively 7 and 8 in FIGS. 1 and 8 in FIGS. 2 and 3) can be excluded. Then in the first case (figure 2) the power of the subsystem 5 should be 22.0% of the total heat load, and the power of the subsystems 6 and 7 - 39.0% each. In the second case (Fig. 3), the power of subsystem 5 should be 15.0% of the total heat load, the power of subsystem 6 is 21.0%, and the power of subsystems 7 and 8 should be 32.0% each.

The minimum number of connected heating subsystems is possible during operation of heating networks with temperature schedules of 120-70 ° C ÷ 130-70 ° C. In the latter case, it is sufficient to divide the connected heating load into two equal parts between two heating subsystems.

References

1.SU 1135972 A, F24D 11/00.

L.F. Krasnoshchekov and E.L. Trukhmanov.

No. 2977205 / 29-33 dated 01.09.80, bull. No. 3, 01/23/.85.

Claims (1)

A water heating system containing a supply and return heating mains, supply and return pipelines of local heating subsystems, a supply piping with branches, a regenerative heat exchanger with inputs and outputs on the heating and cooling sides, heating subsystems, parallel to the heating supply supply via supply pipelines, characterized in that, with a view to the possibility of using a water heating system when connecting one-pipe and two-pipe heating systems to a heating system For rails working with temperature schedules 140-70 ° С, 150-70 ° С and higher, the return pipe of the heating subsystem connected directly to the outlet pipe of the regenerative heat exchanger on the cooling side is connected to the input pipe of the regenerative heat exchanger on the heating side through the supply and return risers one or more heating subsystems directly connected to the heating supply via control valves controlled by temperature controllers with sensors on the supply and return pipes circuits of these heating subsystems, and the recuperative heat exchanger, for controlling the temperature conditions of the heating subsystems connected directly to its outlet pipes on the cooling and heating sides, is equipped with a bypass pipe with a regulating three-way valve installed on it, controlled by a temperature regulator with temperature sensors in the supply and return pipelines of these heating subsystems.

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