CN115574372A - Double-partition large-temperature-difference two-network water supply temperature self-control method and heat exchange device - Google Patents

Abstract

The invention discloses a double-partition large-temperature-difference two-network water supply temperature self-control method, which is based on a heat exchange system for controlling heat input by a unit by controlling the flow of one-network water, wherein the heat exchange system comprises two paths of output of first two-network water and second two-network water, the output flow of the first two-network water is F1, the output temperature is T1, the output flow of the second two-network water is F2, the output temperature is T2, feedback parameters in a closed-loop control loop for controlling the flow of the one-network water are set to be T = (F1 multiplied by T1+ F2 multiplied by T2)/(F1 + F2) + Delta T, wherein the Delta T is a compensation value, and a real-time measured value of T is recorded as T _PV The target value of the adjustment of T is set to T _SV . The invention also discloses a heat exchange device, which realizes the automatic control of one unit driving two different working condition requirements.

Description

Double-partition large-temperature-difference two-network water supply temperature self-control method and heat exchange device

Technical Field

The invention relates to the field of heating, in particular to a double-partition large-temperature-difference two-network water supply temperature self-control method and a heat exchange device.

Background

In the heating industry, a heat exchange station is a bridge connecting a heat source and a user, the heat exchange station is used as a boundary, water circulation from a heating company to the heat exchange station is called one-network water, and water circulation from the heat exchange station to the user is called two-network water.

The core equipment in the heat exchange station is a heat exchange device, namely, the heat exchange device realizes heat exchange, along with the continuous expansion of the heating area of a city, the traditional heating mode using a water-water plate type heat exchanger as the heat exchange device has very large requirements on the temperature and the water supply pressure of a heat source and one network of water (enough hot water must be supplied to ensure the working condition of two networks of water) is developed, in order to reduce the pressure of the heat source and a network, a mode of combining an absorption type large temperature difference heat exchange unit and a water-water heat exchanger is developed, the absorption type large temperature difference heat exchange unit is used for reducing the return water temperature of a primary side, the temperature of the primary side of water is increased, the temperature difference of the primary side of hot water supply and the temperature difference of the return water of the primary side of the hot water are increased, namely, the absorption type large temperature difference heat exchange unit is used for further absorbing the heat energy of the return water of the one network and further increasing the water supply temperature of a small part of the two networks of water, which is equivalent to increasing the heat exchange amount of the one network of water in the heat exchange station, the mode, the pressure on the heat source and the primary side of the heat source and the network can be effectively reduced, but the cost of the absorption type large temperature difference heat exchange unit is higher.

Under the common condition, the building heights of one district are the same, the heating working conditions are basically the same, if one heat exchange station only supplies heat for one district, only one set of heat exchange device is adopted in the heat exchange station, and the flow of network water is controlled by one PID controller, so that the stable supply of heating hot water supplied to users can be ensured.

However, with the development of society, the following problems arise:

one of the situations is: many districts have high-rise buildings (more than 11 floors) and multi-storey buildings (less than 6 floors), or some districts are built on hillside, even if the floors in the district are all 6 floors, but different buildings have great height difference, in this case, the pressure requirement of each building on the heating hot water is different;

in another case: the floor heating is adopted in part of buildings, the wall heating is adopted in part of buildings, the heating temperature of the floor heating is not too high, otherwise the problems that the floor tiles expand with heat and contract with cold, the bulges crack and the like are easily caused, the wall heating requires higher heating temperature to ensure the heating effect, and the temperature requirements for heating hot water between different buildings in the same community are different.

Based on the above situation, if the heat exchange device in the heat exchange station is a traditional plate heat exchanger, two sets of plate heat exchangers are adopted, one part of the building only passes through one set of heat exchanger, and one part of the building passes through two heat exchangers, so that the cost is not increased much, and the problem can be solved; if the heat exchange device is an absorption type large temperature difference heat exchange unit, if two sets of units are adopted to realize different working conditions, the investment is very huge, so that the heat exchange device needs to be designed into a mode of 'one driving two', one absorption type large temperature difference heat exchange unit is adopted, and heating hot water under two working conditions is output.

When the absorption type large-temperature-difference heat exchange unit is used for supplying one heating unit, the temperature of the water outlet of the two networks is unique, and the temperature is used as a unique control target and fed back to the control system to carry out PID (proportion integration differentiation) adjustment on the water regulating valve of the one network, so that the problem is solved, and the problem is solved. However, when a certain heating unit requires two different heating conditions, it is equivalent to generating two control targets of two-network water outlet temperatures, and the original PID control cannot realize the calculation of two target temperatures, which leads to the situation that the original scheme of controlling one-network water flow by one PID controller always easily causes "considering one another", and it is difficult to ensure that stable heating hot water is respectively provided for two partitions.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: when a set of absorption type large-temperature-difference heat exchange unit is used for heating, how to realize the stable and automatic control of the water supply temperature of the two-network water with different parameters of two subareas is realized.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a double-partition large-temperature-difference two-network water supply temperature self-control method is characterized in that a heat exchange system for controlling heat input by a unit is controlled by controlling the flow of one-network water, the heat exchange system comprises two paths of first and second network water for output, the output flow of the first and second network water is F1, the output temperature is T1, the output flow of the second network water is F2, the output temperature is T2, feedback parameters in a closed-loop control loop for controlling the flow of the one-network water are set to be T = (F1 xT 1+ F2 xT 2)/(F1 + F2) + Delta T, wherein the Delta T is a compensation value, and the real-time measured value of T is recorded as T _PV The target value of the adjustment of T is set as T _SV 。

Compared with the prior art, the invention has the following technical effects:

the outlet temperature and the outlet flow of the first net water and the second net water are comprehensively calculated and used as a feedback signal (namely an adjustment target) for controlling the flow of the first net water, so that the automatic control of the flow of the first net water under the situation that the temperature and the flow difference of two subareas are large under the one-to-two scene is realized, and the automatic control of the heat input of the first net water is realized.

On the basis of the technical scheme, the invention can be further improved as follows.

Preferably, the flow of the water in the first network is controlled by a two-way valve arranged on a water pipeline in the first network, and the opening degree of the two-way valve is controlled based on a PID closed-loop control principle to realize the regulation and control of the flow of the water in the first network.

Preferably, when measuring T in real time _PV Less than the adjustment target value T _SV And increasing the opening degree of the two-way valve, and conversely, decreasing the opening degree of the two-way valve.

Preferably, the first net water is divided into a first second net water and a second net water through a three-way valve, the opening degree of the three-way valve is controlled based on a PID control principle, and the difference value of the output temperatures of the first second net water and the second net water is taken as a feedback signal for closed-loop control of the opening degree of the three-way valve.

A heat exchange device comprises an absorption heat exchange main machine, a first heat exchanger and a second heat exchanger,

the absorption type heat exchange main machine comprises a net water supply inlet, a net water supply outlet, a net water return inlet and a net water return outlet, a two-net water return first inlet, a two-net water return first outlet, a two-net water return second inlet and a two-net water return second outlet;

the first heat exchanger comprises a tube side inlet, a tube side outlet, a shell side inlet and a shell side outlet;

the second heat exchanger comprises a tube side inlet, a tube side outlet, a shell side inlet and a shell side outlet;

a two-way valve is arranged on the one-network water supply main pipe connected with the tube pass inlet of the absorption heat exchange main machine or the one-network water return main pipe connected with the one-network water return outlet of the absorption heat exchange main machine;

a net water supply outlet of the absorption type heat exchange host is connected to a three-way valve through a pipeline, and the remaining two outlets of the three-way valve are respectively communicated to a tube pass inlet of the first heat exchanger and a tube pass inlet of the second heat exchanger through pipelines; the tube pass outlet of the first heat exchanger and the tube pass outlet of the second heat exchanger are communicated to a net water return inlet of the absorption heat exchange host machine through pipelines; a first inlet of the secondary-net water backwater is communicated to a shell pass inlet of the first heat exchanger through a pipeline, a first outlet of the secondary-net water backwater is communicated to a second inlet of the secondary-net water backwater through a pipeline, and a second outlet of the secondary-net water backwater is communicated to a shell pass outlet of the first heat exchanger through a pipeline;

a shell pass outlet of the first heat exchanger is connected to a first two-network water supply pipeline, and a first two-network water return pipeline is communicated to a shell pass inlet of the first heat exchanger;

a shell side outlet of the second heat exchanger is connected to a second net water supply pipeline, and a second net water return pipeline is communicated to a shell side inlet of the second heat exchanger;

a first temperature sensor and a first flow sensor are arranged on the first two-network water supply pipeline;

a second temperature sensor and a second flow sensor are arranged on the second network water supply pipeline;

the two-way valve and the three-way valve are electric control valves, and an actuating mechanism of the two-way valve, an actuating mechanism of the three-way valve, the first temperature sensor, the first flow sensor, the second temperature sensor and the second flow sensor are respectively and electrically connected to an automatic control system;

the automatic control system realizes automatic control of the opening degree of the two-way valve based on the automatic control method.

The beneficial effect of adopting the scheme is that

Based on above-mentioned device, can utilize the return water heat that the absorption formula heat transfer host computer further absorbed a net water, and will promote the temperature that a net water supplied water, promote the heat exchange efficiency to a net water heat, and according to the export temperature of first two net waters and second net waters, export flow carries out the overall planning and calculates, as the unit to a net water flow control's feedback signal (also be exactly the adjustment target), realized one drag under two scenes, and two subregion heat supply temperatures, the automatic control of a net water flow under the great situation of flow difference, and then realize the automatic control who drops into heat to a net water.

Furthermore, a condenser, a generator, an evaporator and an absorber are arranged in the absorption type heat exchange host machine, and the condenser, the generator, the evaporator and the absorber are heat exchangers substantially;

the tube pass inlet and the tube pass outlet of the condenser are respectively communicated to a second net water return inlet and a second net water return outlet of the absorption heat exchange host machine through pipelines;

the tube pass inlet and the tube pass outlet of the generator are respectively communicated to a net water supply inlet and a net water supply outlet of the absorption heat exchange host machine through pipelines;

the tube pass inlet and the tube pass outlet of the evaporator are respectively communicated to a net water return inlet and a net water return outlet of the absorption heat exchange host machine through pipelines;

and a tube pass inlet and a tube pass outlet of the absorber are respectively communicated to a first two-network water return inlet and a first two-network water return outlet of the absorption type heat exchange host through pipelines.

Furthermore, a first flow sensor is arranged on the first two-network water supply pipeline, and a second flow sensor is arranged on the second two-network water supply pipeline.

Drawings

FIG. 1 is a schematic structural diagram of a dual-zone large-temperature-difference two-network water supply temperature self-control method of the present invention;

in the drawings, the parts names represented by the respective reference numerals are listed as follows:

1. an absorption heat exchange host; 101. a net water supply inlet; 102. a net water supply outlet; 103. a net water return inlet; 104. a net water backwater outlet; 105. returning water to the first inlet of the second network; 106. returning the water of the second network to the first outlet; 107. a second inlet of the second-network water backwater; 108. the second network water returns to a second outlet;

2. a first heat exchanger; 3. a second heat exchanger; 4. a two-way valve; 5. a three-way valve; 6. a net water supply main pipe; 7. a net water return main pipe; 8. a first two-network water supply pipeline; 9. a first two-network water return pipeline; 10. a second network water supply pipeline; 11. and a second net water return pipeline. 12. A first temperature sensor; 13. a first flow sensor; 14. a second temperature sensor; 15. a second flow sensor; 16. an automatic control system.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

Referring to fig. 1, a heat exchange device includes an absorption heat exchange main unit 1, a first heat exchanger 2 and a second heat exchanger 3,

the absorption type heat exchange host 1 comprises a net water supply inlet 101, a net water supply outlet 102, a net water return inlet 103, a net water return outlet 104, a two-net water return first inlet 105, a two-net water return first outlet 106, a two-net water return second inlet 107 and a two-net water return second outlet 108;

the first heat exchanger 2 comprises a tube side inlet, a tube side outlet, a shell side inlet and a shell side outlet;

the second heat exchanger 3 comprises a tube side inlet, a tube side outlet, a shell side inlet and a shell side outlet;

a two-way valve 4 is arranged on a one-network water supply header pipe 6 connected with a one-network water supply inlet 101 of the absorption heat exchange main machine 1;

a one-network water supply outlet 102 of the absorption heat exchange host 1 is connected to a three-way valve 5 through a pipeline, and the remaining two outlets of the three-way valve 5 are respectively communicated to a tube pass inlet of the first heat exchanger 2 and a tube pass inlet of the second heat exchanger 3 through pipelines; the tube pass outlet of the first heat exchanger 2 and the tube pass outlet of the second heat exchanger 3 are communicated to a net water return inlet 103 of the absorption heat exchange main machine 1 through pipelines; the first secondary-network water backwater inlet 105 is communicated to the shell side inlet of the first heat exchanger 2 through a pipeline, the first secondary-network water backwater outlet 106 is communicated to the second secondary-network water backwater inlet 107 through a pipeline, and the second secondary-network water backwater outlet 108 is communicated to the shell side outlet of the first heat exchanger 2 through a pipeline;

a shell pass outlet of the first heat exchanger 2 is connected to a first two-network water supply pipeline 8, and a first two-network water return pipeline 9 is communicated to a shell pass inlet of the first heat exchanger 2;

a shell pass outlet of the second heat exchanger 3 is connected to a second net water supply pipeline 10, and a second net water return pipeline 11 is communicated to a shell pass inlet of the second heat exchanger 3;

a condenser, a generator, an evaporator and an absorber are arranged in the absorption type heat exchange main machine 1, and the condenser, the generator, the evaporator and the absorber are all heat exchangers substantially, so that the heat exchangers all comprise respective shell passes and tube passes;

the tube pass inlet and the tube pass outlet of the condenser are respectively communicated to a second net water return inlet 107 and a second net water return outlet 108 of the absorption heat exchange host 1 through pipelines;

the tube pass inlet and the tube pass outlet of the generator are respectively communicated to a net water supply inlet 101 and a net water supply outlet 102 of the absorption heat exchange host 1 through pipelines;

a tube pass inlet and a tube pass outlet of the evaporator are respectively communicated to a net water backwater inlet 103 and a net water backwater outlet of the absorption heat exchange main machine 1 through pipelines;

and a tube pass inlet and a tube pass outlet of the absorber are respectively communicated to a first two-network water return inlet 105 and a first two-network water return outlet 106 of the absorption heat exchange host 1 through pipelines.

A first temperature sensor 12 and a first flow sensor 13 are arranged on the first two-network water supply pipeline 8; the temperature measured by the first temperature sensor 12 is recorded as T1, and the flow measured by the first flow sensor 13 is recorded as F1;

a second temperature sensor 14 and a second flow sensor 15 are arranged on the second net water supply pipeline 10; the temperature measured by the second temperature sensor 14 is recorded as T2, and the flow measured by the second flow sensor 15 is recorded as F2;

the two-way valve 4 and the three-way valve 5 are electric control valves, and an actuating mechanism of the two-way valve 4, an actuating mechanism of the three-way valve 5, the first temperature sensor 12, the first flow sensor 13, the second temperature sensor 14 and the second flow sensor 15 are respectively and electrically connected to an automatic control system 16;

in general, when the two-network water of the heating unit operates, the flow rate and the pressure of two subareas (namely the first two-network water and the second two-network water) are constant, so that the water supply temperature of the two-network water is only influenced by the flow rate of the one-network water. As can be seen from fig. 1, the one-network water two-way valve 4 mainly controls the flow rate of one-network water, i.e. the heat input by the unit; the three-way valve 5 mainly controls the distribution of the water flow of one network in two subareas, namely the distribution of the heat of the unit.

The automatic control system 16 controls the opening of the two-way valve 4 based on the PID closed-loop control principle, and sets T = ((F1 × T1+ F2 × T2)/(F1 + F2)) + Δt as a control target (or a feedback signal) of the PID closed-loop control, and a real-time measured value of T is recorded as T _PV The target value of the adjustment of T is set to T _SV After the heating system is put into operation, the flow and the pressure of the first and second network water are fixed and unchanged, so that the total adjustment target value T can be obtained after the target water supply temperature T1sv of the first and second network water and the target water supply temperature T2sv of the second network water are determined _SV Meanwhile, since the flow rate is fixed during normal operation, the signals of the first flow sensor 13 and the second flow sensor 15 do not need to be transmitted to the autonomous system 16, and F1 and F2 are fixed in the calculation formula, in this example, the signals of the two flow sensors are not connected to the autonomous system 16.

When measuring T in real time _PV Is less thanAdjusting the target value T _SV If the opening degree of the two-way valve 4 is increased, otherwise, the opening degree of the two-way valve 4 is decreased, and the opening degree of the two-way valve 4 is automatically adjusted.

As mentioned above, the three-way valve 5 controls the opening of the valve according to the difference between the outlet temperatures of the first and second net waters, and is mainly used for distributing the heat of the first net water to the unit. In this example, the water supply temperature T1 of the first and second grid water is greater than the water supply temperature T2 of the second and second grid water, T3= T1-T2 is set as a target value based on the opening degree of the three-way valve 5 in the PID closed-loop control, in the formula, when T1 and T2 are theoretical target values, the obtained value is the target value T3sv of the PID control of the three-way valve 5, and the value measured in real time during normal operation is the feedback value T3pv of the PID control of the three-way valve 5. Since the total heat is already ensured to be suitable by the two-way valve 4, T1 and T2 do not rise simultaneously (total heat excess) or fall simultaneously (total heat deficiency), and a fluctuation in T3 is only possible in the case of an incorrect heat distribution between the first and second network water. Therefore, when T3pv > T3sv, it means that the outlet temperature T1 of the first and second grid water is lower than the target value, and the outlet temperature T2 of the second grid water is higher than the target value, so that the opening of the three-way valve 5 is adjusted, the flow rate of the first grid water distributed to the first heat exchanger 2 is increased, the flow rate of the first grid water distributed to the second heat exchanger 3 is decreased, so that T1 tends to increase, and T2 tends to decrease; on the contrary, when T3pv < T3sv, it means that the outlet temperature T1 of the first and second grid water is higher than the target value, and the outlet temperature T2 of the second grid water is lower than the target value, so the opening of the three-way valve 5 is adjusted to increase the flow rate of the first grid water distributed into the second heat exchanger 3, and decrease the flow rate of the first grid water distributed into the first heat exchanger 2, so that T1 tends to decrease, and T2 tends to increase.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (7)

1. A double-partition large-temperature-difference two-network water supply temperature self-control method is based on heat exchange for controlling unit input heat by controlling the flow of one-network waterThe system is characterized in that the output flow of the first and second net water is set to be F1, the output temperature is T1, the output flow of the second net water is F2, the output temperature is T2, the feedback parameter in a closed-loop control loop for controlling the flow of the first net water is set to be T = (F1 xT 1+ F2 xT 2)/(F1 + F2) + DeltaT, wherein DeltaT is a compensation value, and the real-time measurement value of T is recorded as T _PV The target value of the adjustment of T is set as T _SV 。

2. The automatic control method for the water supply temperature of the two-network water with the double-partition and the large temperature difference as claimed in claim 1, wherein the flow rate of the one-network water is controlled by a two-way valve arranged on a one-network water pipeline, and the opening degree of the two-way valve is controlled based on a PID closed-loop control principle to realize the regulation and control of the flow rate of the one-network water.

3. The method of claim 1 or 2, wherein the temperature of the water supplied to the two-network is measured in real time _PV Less than the adjustment target value T _SV And increasing the opening degree of the two-way valve, and conversely, decreasing the opening degree of the two-way valve.

4. The method of claim 3, wherein the first net water is divided into a first net water and a second net water by a three-way valve, the opening of the three-way valve is controlled based on the PID control principle, and the feedback signal for the closed-loop control of the opening of the three-way valve is the difference between the output temperatures of the first net water and the second net water.

5. A heat exchange device comprises an absorption type heat exchange host, a first heat exchanger and a second heat exchanger, wherein the absorption type heat exchange host comprises a net water supply inlet, a net water supply outlet, a net water return inlet, a net water return outlet, a second net water return first inlet, a second net water return first outlet, a second net water return second inlet and a second net water return second outlet;

the first heat exchanger comprises a tube side inlet, a tube side outlet, a shell side inlet and a shell side outlet;

the second heat exchanger comprises a tube side inlet, a tube side outlet, a shell side inlet and a shell side outlet;

it is characterized in that the preparation method is characterized in that,

a two-way valve is arranged on the one-network water supply header pipe connected with the one-network water supply inlet of the absorption heat exchange main machine or the one-network water return header pipe connected with the one-network water return outlet of the absorption heat exchange main machine;

a net water supply outlet of the absorption type heat exchange host is connected to a three-way valve through a pipeline, and the remaining two outlets of the three-way valve are respectively communicated to a tube pass inlet of the first heat exchanger and a tube pass inlet of the second heat exchanger through pipelines; the tube pass outlet of the first heat exchanger and the tube pass outlet of the second heat exchanger are communicated to a net water return inlet of the absorption heat exchange main machine through pipelines; a first inlet of the secondary-net water backwater is communicated to a shell pass inlet of the first heat exchanger through a pipeline, a first outlet of the secondary-net water backwater is communicated to a second inlet of the secondary-net water backwater through a pipeline, and a second outlet of the secondary-net water backwater is communicated to a shell pass outlet of the first heat exchanger through a pipeline;

a shell pass outlet of the first heat exchanger is connected to a first two-network water supply pipeline, and a first two-network water return pipeline is communicated to a shell pass inlet of the first heat exchanger;

a shell side outlet of the second heat exchanger is connected to a second net water supply pipeline, and a second net water return pipeline is communicated to a shell side inlet of the second heat exchanger;

a first temperature sensor is arranged on the first water supply pipeline of the second network and the third network;

a second temperature sensor is arranged on the second net water supply pipeline;

the two-way valve and the three-way valve are electric control valves, and an actuating mechanism of the two-way valve, an actuating mechanism of the three-way valve, the first temperature sensor and the second temperature sensor are respectively and electrically connected to an automatic control system;

the autonomous system performs automatic control according to the autonomous method of any one of claims 1 to 4.

6. The heat exchange device of claim 5, wherein a condenser, a generator, an evaporator and an absorber are arranged in the absorption heat exchange main machine;

a pipe pass inlet and a pipe pass outlet of the condenser are respectively communicated to a secondary-network water backwater second inlet and a secondary-network water backwater second outlet of the absorption heat exchange host through pipelines;

the tube pass inlet and the tube pass outlet of the generator are respectively communicated to a net water supply inlet and a net water supply outlet of the absorption heat exchange host machine through pipelines;

a tube pass inlet and a tube pass outlet of the evaporator are respectively communicated to a net water backwater inlet and a net water backwater outlet of the absorption heat exchange host through pipelines;

and a tube pass inlet and a tube pass outlet of the absorber are respectively communicated to a first two-network water return inlet and a first two-network water return outlet of the absorption type heat exchange host through pipelines.

7. The heat exchange device of claim 5, wherein a first flow sensor is arranged on the first two-network water supply pipeline, and a second flow sensor is arranged on the second two-network water supply pipeline.

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