Heat exchange system capable of effectively reducing end difference of heat exchanger

Abstract

The utility model provides a heat exchange system capable of effectively reducing the end difference of a heat exchanger, and belongs to the technical field of heat supply. The problem that the end difference of heat exchangers in an existing central heating system is too large is solved. The system comprises a first-level network system and a second-level network system. The first-stage network system comprises a first-stage heat exchanger, a second-stage heat exchanger and a bypass ball valve; operation of the first-level network system is divided into parallel connection and series connection; during parallel connection, supplied water enters the first-stage heat exchanger and the second-stage heat exchanger for heat exchange and then enters a heat supply system large network; during series connection, supplied water firstly enters the first-stage heat exchanger, then enters the second-stage heat exchanger for heat exchange through the bypass ball valve and then enters a heat supply system large network; the second-stage network system comprises a circulating water pump, a first-stage heat exchanger, a second-stage heat exchanger and a pressure-equalizing water mixing tank; and return water enters the first-stage heat exchanger and the second-stage heat exchanger through a circulating water pump, is mixed by a pressure-equalizing water mixing tank and then enters a heat supply system large network. The utility model effectively solves the problem of overlarge end difference of the heat exchanger of the heat exchange unit in the existing central heating system, and reduces the energy consumption of the heating system.

Description

TECHNICAL FIELD

[0001] The utility model relates to the design and operation optimization technology of heat exchange unit in heat supply system, especially relates to a heat exchange system that effectively reduces heat exchanger terminal difference. BACKGROUND

[0002] With the increasing speed of urbanization, the total amount of construction increases rapidly. At the same time, the demand for central heating heat load increases year by year, and the problem of insufficient heat supply system heat network transmission capacity gradually appears, which brings many challenges to the stable and efficient operation of the heat supply system.

[0003] At present, the heat exchange station of heat supply system heat exchange unit one network supply and return water design operation temperature is 98℃ / 52℃, the two network supply and return water design operation temperature is 60℃ / 45℃, and the terminal difference between the heat exchanger one network return water and two network return water is 7℃. Practice shows that under the condition of the same flow, the whole pipe network heating capacity can be improved by 2.17% per 1℃ terminal difference. In view of this defect and problem, it is urgent to design a heat exchange system that effectively reduces the terminal difference of heat exchanger to improve the performance of heat supply system and better meet the increasing demand for heating. SUMMARY

[0004] In the following, a brief summary of the utility model is given to provide a basic understanding of some aspects of the utility model. It should be understood that this summary is not an exhaustive summary of the utility model. It is not intended to determine the key or important parts of the utility model, nor is it intended to limit the scope of the utility model. Its purpose is only to give some concepts in a simplified form as a prelude to the more detailed description discussed later.

[0005] In view of this, in order to solve the problem of excessive terminal difference of heat exchanger in the heat exchange unit of existing central heating system heat exchange station, the utility model provides a heat exchange system that effectively reduces the terminal difference of heat exchanger.

[0006] The utility model technical scheme is a heat exchange system that effectively reduces the terminal difference of heat exchanger, which comprises a one network system and a two network system.

[0007] The one network system and the two network system share a one heat exchanger and a two heat exchanger.

[0008] The primary network system comprises a primary network water supply port, a primary heat exchanger, a secondary heat exchanger, a bypass ball valve, and a primary network return water port; the primary network system has two operation modes, namely parallel operation and series operation; in the parallel operation mode, the water supply of the primary network enters the primary heat exchanger and the secondary heat exchanger through pipelines respectively, and then the return water enters the heating system large network through the primary network return water port; in the series operation mode, the water supply of the primary network enters the primary heat exchanger through a pipeline from the primary network water supply port, and then the return water of the primary heat exchanger enters the secondary heat exchanger through the bypass ball valve for heat exchange, and the return water of the secondary heat exchanger enters the heating system large network through the primary network return water port.

[0009] The secondary network system comprises a secondary network return water port, a circulating water pump, a primary heat exchanger, a secondary heat exchanger, a pressure equalization water mixing tank, and a secondary network water supply port; the secondary network system has a parallel operation mode, in which the return water of the secondary network enters the secondary heat exchanger and the primary heat exchanger through a pipeline from the secondary network return water port via the circulating water pump for heat exchange, and then the mixed water enters the heating system large network through the secondary network water supply port after the heat exchange is completed.

[0010] Further, the pipeline connected between the primary heat exchanger and the secondary heat exchanger is provided with a water supply ball valve.

[0011] Further, the primary heat exchanger and the secondary heat exchanger are wide-flow-channel deep-spaced corrugated plate type.

[0012] Compared with the prior art, the utility model has the following beneficial effects:

[0013] 1. The utility model effectively solves the problem of excessive end difference of the heat exchanger of the heat exchange unit in the existing central heating system heat exchange station, and reduces the energy consumption of the heating system.

[0014] 2. In the utility model, the primary network system operation adopts a series-parallel switchable system, which ensures that the heating system can be relatively stably operated under different pressure difference conditions, enhances the adaptability of the heating system to different working conditions, and solves the problem of insufficient heat network transmission capacity of the heating system.

[0015] 3. The utility model solves the problems of low heat transfer coefficient and poor heat exchange efficiency of the heat exchanger caused by excessive flow difference between the primary side and the secondary side of the existing heat exchange unit, improves the heat exchange performance of the heat exchanger, and greatly improves the heating capacity of the heating pipe network. BRIEF DESCRIPTION OF DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the utility model and form a part of the utility model, and the schematic embodiments of the utility model and the description thereof are used to explain the utility model and do not constitute an improper limitation on the utility model. In the drawings:

[0017] Figure 1A schematic view of a heat exchange system capable of effectively reducing the end difference of a heat exchanger.

[0018] In the figure: 1 - primary network water supply port, 2 - primary heat exchanger, 3 - secondary heat exchanger, 4 - bypass ball valve, 5 - primary network backwater port, 6 - secondary network backwater port, 7 - circulating water pump, 8 - pressure equalization mixing tank, 9 - secondary network water supply port. DETAILED DESCRIPTION

[0019] In order to make the technical solutions and advantages in the embodiments of the utility model clearer and more apparent, the exemplary embodiments of the utility model are further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than an exhaustive enumeration of all embodiments. It should be noted that the embodiments in the utility model and the features in the embodiments can be combined with each other without conflict.

[0020] Embodiment 1, refer to Figure 1 The heat exchange system capable of effectively reducing the end difference of a heat exchanger comprises a primary network system and a secondary network system.

[0021] The primary network system and the secondary network system share the primary heat exchanger 2 and the secondary heat exchanger 3.

[0022] The primary network system comprises a primary network water supply port 1, a primary heat exchanger 2, a secondary heat exchanger 3, a bypass ball valve 4, and a primary network backwater port 5. The operation mode of the primary network system is divided into parallel connection and series connection. In the parallel connection operation mode, the water supply of the primary network enters the primary heat exchanger 2 and the secondary heat exchanger 3 through the pipeline from the primary network water supply port 1, and then the backwater enters the heating system large network through the primary network backwater port 5 after heat exchange. In the series connection operation mode, the water supply of the primary network enters the primary heat exchanger 2 through the pipeline from the primary network water supply port 1, and then the backwater of the primary heat exchanger 2 enters the secondary heat exchanger 3 through the bypass ball valve 4 for heat exchange, and the backwater of the secondary heat exchanger 3 enters the heating system large network through the primary network backwater port 5.

[0023] The secondary network system comprises a secondary network backwater port 6, a circulating water pump 7, a primary heat exchanger 2, a secondary heat exchanger 3, a pressure equalization mixing tank 8, and a secondary network water supply port 9. The operation mode of the secondary network system is parallel connection. The backwater of the secondary network enters the secondary heat exchanger 3 and the primary heat exchanger 2 through the pipeline from the secondary network backwater port 6 via the circulating water pump 7 for heat exchange, and then enters the heating system large network through the secondary network water supply port 9 after mixing in the pressure equalization mixing tank 8.

[0024] Further, the pipeline connected between the primary heat exchanger 2 and the secondary heat exchanger 3 is provided with a ball valve.

[0025] Further, the primary network system switches operation mode according to the service pressure difference, when the service pressure difference is sufficient, the bypass ball valve 4 is opened, the primary network water supply pipeline ball valve of the secondary heat exchanger 3 is closed, and the operation mode is switched to series connection.

[0026] Further, the primary heat exchanger 2 and the secondary heat exchanger 3 are wide flow channel deep sparse wave plate type.

[0027] Further, the design parameter calculation method of the primary heat exchanger 2 and the secondary heat exchanger 3, specifically includes:

[0028] Design the load of the primary heat exchanger 2: Q1=Q-(Q×(T h -t h -1) / (T g -t h -1));

[0029] Design the water supply temperature of the primary heat exchanger 2 of the primary network system: T g1 =T g ;

[0030] Design the return water temperature of the primary heat exchanger 2 of the primary network system: T h1 =T h ;

[0031] When the flow rates of the primary heat exchanger 2 and the secondary heat exchanger 3 on the secondary side are the same, design the water supply temperature of the primary heat exchanger 2 of the secondary network system: t g1 =2t g -t h -(2×(t g -t h )×(T h -t h -1) / (T g -t h -1));

[0032] Design the return water temperature of the primary heat exchanger 2 of the secondary network system: t h1 =t h ;

[0033] Design the load of the secondary heat exchanger 3: Q2=Q×(T h -t h -1) / (T g -t h -1);

[0034] Design the water supply temperature of the secondary heat exchanger 3 of the primary network system: T g2 =T h ;

[0035] Design the return water temperature of the secondary heat exchanger 3 of the primary network system: T h2 =th +1;

[0036] When the flow rates of the secondary sides of the primary heat exchanger 2 and the secondary heat exchanger 3 are the same, the design supply water temperature of the secondary heat exchanger 3 of the secondary network system is t g2 =2×(t g -t h )×(T h -t h -1) / (T g -t h -1)+t h ;

[0037] The design return water temperature of the secondary heat exchanger 3 of the secondary network system is t h2 =t h ;

[0038] Wherein, the design load of the primary heat exchanger 2 and the secondary heat exchanger 3 is Q, the design supply water temperature of the primary network system is T g , the design return water temperature of the primary network system is T h , the design supply water temperature of the secondary network system is t g , and the design return water temperature of the secondary network system is t h .

[0039] Further, the pressure drops of the primary heat exchanger 2 and the secondary heat exchanger 3 in the secondary network system design are the same.

[0040] Further, the flow rate of the circulating water pump 7 is calculated according to the total design load of the primary heat exchanger 2 and the secondary heat exchanger 3 and the temperature difference of the secondary network system design, and the head of the circulating water pump 7 is calculated according to the maximum pressure drop of the secondary network system of the primary heat exchanger 2 and the secondary heat exchanger 3.

[0041] Further, the volume of the pressure equalization water mixing tank 8 is determined according to the total circulating flow rate and pressure of the primary heat exchanger 2 and the secondary heat exchanger 3, so that the different supply water temperatures of the secondary network system of the primary heat exchanger 2 and the secondary heat exchanger 3 are fully mixed, and the mixed temperature is the design supply water temperature of the secondary network system of the primary heat exchanger 2 and the secondary heat exchanger 3.

[0042] By the utility model, the problem of excessive end difference of the heat exchanger of the heat exchange unit in the existing central heating system heat exchange station can be effectively solved, the energy consumption of the heating system is reduced, the problems of low heat transfer coefficient and poor heat exchange efficiency of the heat exchanger caused by excessive flow difference between the primary side and the secondary side of the existing heat exchange unit are solved, the heat exchange performance of the heat exchanger is improved, and the heating capacity of the heating pipe network is greatly improved.

[0043] The series-parallel switchable primary network system guarantees that the heat supply system can be relatively stably operated under different pressure difference conditions, enhances the adaptability of the heat supply system to different working conditions, and solves the problem of insufficient heat network conveying capacity of the heat supply system.

[0044] Although the utility model has been described in terms of a limited number of embodiments, those skilled in the art, having the benefit of the above description, will appreciate that other embodiments can be conceived within the scope of the utility model thus described. Furthermore, it should be noted that the language used in the specification has been chosen primarily for readability and instructional purposes and can not have been selected to convey or to limit the subject matter of the utility model. Accordingly, numerous modifications and alterations are possible without departing from the scope and spirit of the appended claims. In terms of the scope of the utility model, the disclosure of the utility model is illustrative rather than restrictive, and the scope of the utility model is defined by the appended claims.

Claims

1. A heat exchange system for effectively reducing the terminal temperature difference of a heat exchanger, characterized in that, Including primary network systems and secondary network systems; The primary network system and the secondary network system share the primary heat exchanger (2) and the secondary heat exchanger (3); The primary network system includes a primary network water inlet (1), a primary heat exchanger (2), a secondary heat exchanger (3), a bypass ball valve (4), and a primary network return water inlet (5). The primary network system operates in two modes: parallel and series. In the parallel operation mode, the water supplied by the primary network enters the primary heat exchanger (2) and the secondary heat exchanger (3) through the primary network water inlet (1) via pipelines. After heat exchange, the return water enters the main heating network through the primary network return water inlet (5). In the series operation mode, the water supplied by the primary network enters the primary heat exchanger (2) through the primary network water inlet (1) via pipelines. After heat exchange, the return water from the primary heat exchanger (2) enters the secondary heat exchanger (3) through the bypass ball valve (4) for heat exchange. The return water from the secondary heat exchanger (3) enters the main heating network through the primary network return water inlet (5). The secondary network system includes a secondary network return water inlet (6), a circulating water pump (7), a primary heat exchanger (2), a secondary heat exchanger (3), a pressure equalization mixing tank (8), and a secondary network supply water inlet (9). The secondary network system operates in parallel. The secondary network return water enters the secondary heat exchanger (3) and the primary heat exchanger (2) through the circulating water pump (7) via the secondary network return water inlet (6) for heat exchange. After heat exchange, the water is mixed in the pressure equalization mixing tank (8) and then enters the main heating network through the secondary network supply water inlet (9).

2. The heat exchange system for effectively reducing the terminal temperature difference of a heat exchanger according to claim 1, characterized in that, Water supply ball valves are installed on the pipes connecting the primary heat exchanger (2) and the secondary heat exchanger (3).

3. The heat exchange system for effectively reducing the terminal temperature difference of a heat exchanger according to claim 1, characterized in that, The primary heat exchanger (2) and the secondary heat exchanger (3) are wide-channel, deep-corrugated plate types.

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