Industrial waste heat utilization system including energy storage unit and design method thereof

Abstract

The present invention discloses a chemical waste heat utilization system including an energy storage unit and a design method thereof, comprising the following steps: (1) acquiring the flow data of the industrial system; (2) formulating energy targets for each single-cycle industrial system; (3) based on the energy characteristics of each flow of the industrial system in a single cycle, dividing the industrial system into blocks and calculating the heat exchange network structure corresponding to the industrial system under the cycle; (4) integrating the multi-cycle heat exchange network structure and energy targets, determining the optimal installation position of the multi-layer energy storage unit, and obtaining the heat exchange network of the industrial system including the energy storage unit. The present invention is based on the topological optimization design of the single-cycle heat exchange network, combined with actual operating parameters, and coupled with the energy storage unit while expanding to the multi-cycle heat exchange network, which can effectively improve the waste heat utilization efficiency of the industrial system and achieve excellent economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of waste heat recovery and utilization of industrial systems, and in particular to an industrial waste heat utilization system comprising an energy storage unit and a design method thereof. Background Art

[0002] With the rapid development of modern life and industrial production, energy and environmental issues have become hot issues that have attracted global attention in recent years. As a representative energy-intensive industry, the industrial system involves a large amount of heat exchange and energy consumption. In chemical production, in order to meet specific process requirements, it is usually necessary to heat or cool the working fluid to a specific temperature before production. There are many high-temperature and low-temperature fluids in the industrial system itself. Through the design of the heat exchange network, high-temperature fluids can be used to heat low-temperature fluids, and low-temperature fluids can be used to cool high-temperature fluids. By matching and exchanging hot and cold fluids, while achieving the target temperature of the fluid, it is also possible to utilize chemical waste heat and reduce carbon footprint.

[0003] Traditional heat exchange network research is usually applied to the energy optimization of production processes under a single cycle. In actual production processes, the temperature, flow rate, physical properties, etc. of each stream in the industrial system are changing, and the heating or cooling energy required for each stream also changes over time. Single-cycle heat exchange network optimization is difficult to solve these problems. Summary of the invention

[0004] In view of the above problems, the present invention proposes for the first time to achieve the above objectives in the same system and discloses the method thereof.

[0005] One of the purposes of the present invention is to provide a method for designing an industrial waste heat utilization system including an energy storage unit, comprising:

[0006] Step 1: Obtain the flow data of the industrial system;

[0007] Step 2: Set energy targets for each single-cycle industrial system;

[0008] Step 3: Based on the energy characteristics of each stream of the industrial system in a single cycle, the industrial system is divided into blocks and the heat exchange network structure corresponding to the industrial system in the cycle is calculated;

[0009] Step 4: Integrate the multi-cycle heat exchange network structure and energy target, determine the installation location of the energy storage unit, and obtain the industrial system heat exchange network including the energy storage unit.

[0010] In order to better implement the present invention, the following optimization scheme can be adopted:

[0011] The stream data of the industrial system in step 1 at least include the initial temperature, target temperature, specific heat capacity and / or flow rate of each stream. One hour can be taken as a single cycle time, and the average value within one hour is taken as the stream data corresponding to the cycle.

[0012] Furthermore, the step 2 also includes, based on the industrial system flow data obtained in step 1, drawing an energy composite curve corresponding to each cycle, determining the pinch point temperature of each cycle through the energy composite curve; and calculating the theoretical utility consumption required for the industrial system in each cycle; integrating the pinch point temperature and theoretical utility consumption of each cycle to obtain a multi-pinch point temperature distribution diagram and the maximum and minimum theoretical utility consumption required in each cycle.

[0013] Furthermore, the step 3 also includes:

[0014] Step 301: Based on the energy composite curve corresponding to each cycle obtained in step 2, the energy composite curve in each cycle is divided into blocks, and the block division is based on the slope of the composite curve of the cold and hot streams, and the composite curves with similar slopes are merged into one block; the boundary enthalpy value and boundary temperature of each block after the block division are obtained, and the heat exchange network modeling and calculation are carried out for the industrial system of each block, and a mixed integer nonlinear superstructure heat exchange network model is constructed;

[0015] Step 302, combining the heat exchange network structures designed for each block in the same cycle to construct a single-cycle heat exchange network;

[0016] Step 303: re-determine the installation location, actual usage and / or temperature range of the cold and hot utilities required by the heat exchange network in each cycle according to the heat exchange network.

[0017] Furthermore, the step 4 also includes:

[0018] Step 401, based on the obtained overall design of each periodic heat exchange network and the utility engineering information, determine the energy difference existing in each block of the heat exchange network of different periods;

[0019] Step 402: Based on the energy difference and the temperature range, determine the possibility of direct heat exchange of utilities in different periods;

[0020] Step 403: When the minimum heat transfer temperature difference is met, the utilities of different periods of the industrial system can directly exchange heat; when the minimum heat transfer temperature difference is not met, return to step 3;

[0021] Step 404: Based on the industrial system operation cycle, heat exchange network blocks and energy difference information, determine the installation location, capacity and cost of the energy storage unit through mathematical modeling;

[0022] Step 405, economic test, when the economic requirements are met, an industrial waste heat utilization system including an energy storage unit is obtained, when the economic requirements are not met, return to step 403, and reconfigure the direct heat exchange of the utilities in different periods of the industrial system.

[0023] Preferably, step 403 further includes utilizing the extra waste heat resources in the previous operation cycle to charge the energy storage unit; and / or utilizing the charged energy storage unit to release heat to the heat exchange network in the subsequent operation cycle.

[0024] A second object of the present invention is to provide an industrial waste heat utilization system including an energy storage unit, comprising:

[0025] hot streams, whose initial temperature is higher than the target temperature;

[0026] cold stream, whose initial temperature is lower than the target temperature;

[0027] Heat utility engineering is used to continue heating the cold stream to the target temperature when the cold stream fails to reach the required target temperature after heat exchange with the hot stream;

[0028] Cold utility engineering is used to continue cooling the hot stream to the target temperature when the hot stream fails to reach the required target temperature after heat exchange with the cold stream;

[0029] Process heat exchangers are used to connect cold streams and hot streams to achieve energy exchange between cold and hot streams in chemical process systems;

[0030] Utility heat exchangers for connecting a cold stream to a hot utility, or a hot stream to a cold utility; and

[0031] The energy storage unit is connected to the hot flow stream through the charging pipeline to store the heat of the hot flow stream in the energy storage unit; and the energy storage unit is connected to the cold flow stream through the energy release pipeline to release the heat of the energy storage unit to the cold flow stream through the energy release pipeline.

[0032] Preferably, the energy storage unit has multiple layers of energy storage materials, and each layer of energy storage material is independent of each other and connected in series.

[0033] Preferably, electric valves are provided between each layer of energy storage material to control the amount of energy storage material participating in the energy storage reaction.

[0034] Preferably, there are multiple energy storage units.

[0035] Preferably, the hot utility is hot water or steam and the cold utility is cold water or air.

[0036] Compared with the prior art, the present invention also has the following advantages and beneficial effects:

[0037] (1) By setting up an energy storage unit in the industrial waste heat utilization system, heat transfer across cycles in the heat exchange network can be achieved. The excess heat generated in the previous cycle is stored in the energy storage unit and used to heat the cold stream in the subsequent cycle, which can reduce or completely eliminate the use of utilities and save energy.

[0038] (2) Establish a multi-cycle heat exchange network model with hours as the cycle unit to improve the flexibility and stability of the heat exchange network design.

[0039] (3) The present invention designs the required heat exchange network through mathematical modeling of nonlinear superstructure heat exchange network, proposes the optimal design scheme of energy storage unit, optimizes the energy recovery of the system, and realizes the efficient utilization of waste heat of industrial system.

[0040] The above description is only an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and to enable those skilled in the art to implement it according to the contents of the specification, and to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described below by way of example. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0042] In the accompanying drawings,

[0043] Figure 1 It is a schematic diagram of the main steps of the system design of the present invention.

[0044] Figure 2 It is a schematic flow chart of the industrial waste heat utilization system design method of the present invention.

[0045] Figure 3 It is a schematic diagram of an industrial waste heat utilization system including a multi-layer energy storage unit according to the present invention. DETAILED DESCRIPTION

[0046] The following will refer to the attached Figures 1 to 3The specific implementation process of the present invention is described in more detail. In addition, the same reference numerals are used to represent the same components throughout the accompanying drawings. Although specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0047] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned in the entire specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be defined by the attached claims. To facilitate the understanding of the embodiments of the present invention, the following will be further explained with reference to specific embodiments as an example in conjunction with the accompanying drawings, and each drawing does not constitute a limitation on the embodiments of the present invention.

[0048] For a better understanding, Figure 1-2 As shown, a design method for an industrial waste heat utilization system including an energy storage unit, the specific implementation steps include:

[0049] Step 1: Obtain the flow data of the industrial system;

[0050] Step 2: Set energy targets for each single-cycle industrial system;

[0051] Step 3: Based on the energy characteristics of each stream of the industrial system in a single cycle, the industrial system is divided into blocks and the heat exchange network structure corresponding to the industrial system in the cycle is calculated;

[0052] Step 4: Integrate the multi-cycle heat exchange network structure and energy target, determine the installation location of the energy storage unit, and obtain the industrial system heat exchange network including the energy storage unit.

[0053] In the step 1, the stream data of the industrial system at least includes the initial temperature, target temperature, specific heat capacity and / or flow rate of each stream. The industrial system takes into account the volatility of logistics data under actual working conditions, takes one hour as a single cycle time, takes the average value within one hour as the corresponding data of the cycle, and determines the stream data in the industrial system.

[0054] The step 2, setting energy targets for the industrial system in each single cycle, further includes the following implementation steps: based on the industrial system logistics data obtained in step 1, drawing an energy composite curve corresponding to each cycle, the energy composite curve can be, for example, a TH diagram. Determine the pinch point temperature of each cycle through the energy composite curve; and calculate the theoretical utility usage required in each cycle, including the theoretical usage of cold utilities and hot utilities; integrate the pinch point temperature and theoretical utility usage of each cycle to obtain a multi-pinch point temperature distribution diagram and the maximum and minimum theoretical utility usage required in each cycle. The maximum and minimum theoretical utility usage are the energy targets, which are used to calculate the operating costs of each cycle.

[0055] The step 3 is based on the energy characteristics of the hot and cold streams of the industrial system in a single cycle, divides the industrial system into blocks and calculates the heat exchange network structure corresponding to the industrial system in the cycle, and its implementation steps further include:

[0056] Step 301, based on the energy composite curve corresponding to each cycle obtained in step 2, the energy composite curve in each cycle is divided into blocks. The block division is based on the slope of the composite curve of the cold and hot streams, and the composite curves with similar slopes are merged into one block; after the block division, the boundary enthalpy and boundary temperature of each block are obtained, and the heat exchange network modeling and calculation are carried out for the industrial system of each block, and a mixed integer nonlinear superstructure heat exchange network model is constructed. By jointly constructing the mathematical model of the heat exchange network by integer nonlinearity and superstructure, the heat exchange network structure of the system is further optimized. On this basis, the optimal design scheme of the energy storage unit is proposed, which optimizes the recovery of system energy and realizes the efficient utilization of waste heat in the industrial system.

[0057] Step 302: Combine the heat exchange network structures designed for each block in the same cycle to construct a single-cycle heat exchange network.

[0058] Step 303: re-determine the installation location, actual usage and / or temperature range of the cold and hot utilities required by the heat exchange network in each cycle according to the heat exchange network.

[0059] Step 3 may also include verifying and comparing the actual usage of cold and hot utilities in each cycle with the theoretical usage of utilities, so as to adjust the installation location, actual usage and / or temperature range of the cold and hot utilities required by the heat exchange network in each cycle. Steps 2 and 3 may also include energy consumption calculation, and further verify the heat exchange network design through energy consumption comparison of each cycle.

[0060] The step 4 integrates the multi-cycle heat exchange network structure and energy target to determine the installation location of the energy storage unit. The specific implementation steps include:

[0061] Step 401: Based on the obtained information of each periodic heat exchange network and public engineering, determine the energy difference existing in each block in each periodic heat exchange network.

[0062] Step 402: Based on the energy difference and the temperature range, determine the possibility of direct heat exchange of the public works in each period.

[0063] Step 403: When the minimum heat transfer temperature difference is met, the utilities of different cycles of the industrial system can directly exchange heat, that is, the additional waste heat resources in the previous operation cycle are used to charge the energy storage unit, which simultaneously reduces the use of cold utilities in the cycle; and / or the charged energy storage unit is used to release heat to the heat exchange network of the subsequent operation cycle, replacing the originally required hot utilities, further improving the waste heat utilization rate and reducing the operating cost; when the minimum heat transfer temperature difference is not met, return to step 3.

[0064] Step 404: Based on the industrial system operation cycle, heat exchange network blocks and energy difference information, determine the installation location, capacity and cost of the energy storage unit through mathematical modeling.

[0065] Step 405, economic test, when the economic requirements are met, the industrial waste heat utilization system including the energy storage unit is obtained, when the economic requirements are not met, return to step 403, reconfigure the direct heat exchange of the utilities in different periods of the industrial system. The economic requirements are tested by setting an economic objective function, which usually includes energy cost, heat exchanger cost and energy storage unit cost to test whether the specified investment recovery period can be met.

[0066] The present invention realizes cross-cycle waste heat energy recovery and utilization by adding an energy storage unit to the industrial waste heat utilization system.

[0067] See attached Figure 3 The present invention also provides an industrial waste heat utilization system including an energy storage unit, comprising:

[0068] Hot stream 6 and hot stream 7 are production materials in the industrial system. Their initial temperature is higher than the target temperature. The stream temperature needs to be cooled in the chemical process to meet production requirements.

[0069] Cold stream 8 and cold stream 9 are production materials in the industrial system. Their initial temperature is lower than the target temperature. The stream temperature needs to be heated in the chemical process to meet production requirements.

[0070] Thermal utilities 14, an external heat source independent of the cold and hot streams. If the cold stream fails to reach the required target temperature after heat exchange with the hot stream, it can continue to be heated to the target temperature through thermal utilities. Common thermal utilities include hot water, steam, etc., which are relatively expensive;

[0071] Cold utility engineering 13, an external heat source independent of the cold and hot streams. If the hot stream fails to reach the required target temperature after heat exchange with the cold stream, it can continue to cool to the target temperature through the cold utility engineering. Common cold utilities include cold water, air, etc., which are relatively low in cost;

[0072] Process heat exchanger 1, process heat exchanger 2, process heat exchanger 3, process heat exchanger 4 and process heat exchanger 5 are used to connect the cold stream and the hot stream to realize energy exchange between the cold and hot streams in the chemical process system, and can fully or partially meet the temperature targets of the cold and hot streams.

[0073] Utility heat exchangers 10, 11 and 12 are used to connect the cold flow with the hot utility, or the hot flow with the cold utility, to fully meet the temperature targets of the cold and hot flow.

[0074] Energy storage unit 15, charging pipeline 19 and energy release pipeline 20. The energy storage unit 15 is connected to the hot stream 7 through the charging pipeline 19 to store the heat of the hot stream 7 in the energy storage unit 15. While meeting the target temperature of the hot stream 7, the amount of cold utility engineering 13 is completely eliminated or reduced. The energy storage unit 15 is connected to the cold stream 8 and the cold stream 9 through the energy release pipeline 20 to release the heat of the energy storage unit 15 to the cold stream 8 and the cold stream 9 through the energy release pipeline 20, while meeting the target temperature of the cold stream 8 and the cold stream 9, the amount of hot utility engineering 14 is completely eliminated or reduced, thereby achieving efficient utilization of waste heat energy. Preferably, the energy storage unit 15 has multiple layers of energy storage materials 16, and each layer of energy storage materials is independent of each other and connected in series. Electric valves 17 and electric valves 18 are arranged between each layer of energy storage materials to control the amount of energy storage materials participating in the energy storage reaction, thereby achieving control of the storage energy. When the electric valve 17 is in the open state, the energy storage material 16 of this layer participates in the energy storage reaction; when the electric valve 18 is in the closed state, the energy storage material 16 of this layer does not participate in the energy storage reaction; thus, an energy storage unit can be set up to meet the energy storage requirements under different energy storage needs.

[0075] Furthermore, the energy storage unit 15 of the present invention may be multiple. In order to better illustrate the embodiment, an industrial waste heat utilization system including two operation cycles is now used for illustration. Figure 3 As shown, the industrial waste heat utilization system includes: hot stream 6, hot stream 7, cold stream 8, cold stream 9, hot public works 14, cold public works 13, process heat exchanger 1, process heat exchanger 2, process heat exchanger 3, process heat exchanger 4, process heat exchanger 5, used to connect the cold stream and the hot stream; public works heat exchanger 10, public works heat exchanger 11, public works heat exchanger 12, used to connect the cold stream with the hot public works, or the hot stream with the cold public works.

[0076] Operation cycle A and operation cycle B are two different operation cycles of the industrial waste heat utilization system.

[0077] See attached Figure 3 In operation cycle A, process heat exchangers 1 and 2 respectively connect hot stream 6 with cold stream 8 and cold stream 9, and use the heat of hot stream 6 to heat cold stream 8 and cold stream 9. While lowering the temperature of hot stream 6, the temperature of cold stream 8 and cold stream 9 is increased to realize the waste heat utilization in the system. However, after cold stream 8 and cold stream 9 realize heat exchange with hot stream 6 through process heat exchangers 1 and 2, the stream temperature is still not heated to the target temperature. It is necessary to continue to heat cold stream 8 and cold stream 9 to the target temperature through thermal utility 14. Utility heat exchangers 11 and 12 respectively connect cold stream 8 and cold stream 9 with thermal utility 14 to realize the continued heating of cold stream 8 and cold stream 9 by thermal utility 14 to meet the process requirements. At this time, the hot stream 7 does not participate in any heat exchange with the cold stream, so in order to cool the hot stream 7 to the target temperature, a large amount of cold utilities 13 are originally required for cooling the hot stream 7.

[0078] In operation cycle B, hot stream 7 exchanges heat with cold stream 8 and cold stream 9 through process heat exchanger 3 and process heat exchanger 4 respectively. This process can reduce the temperature of hot stream 7 and increase the temperature of cold stream 8 and cold stream 9. However, after heat exchange, the temperature of hot stream 7 still does not reach the target temperature, so it needs to be further cooled to meet the process requirements. At this time, the utility heat exchanger 10 is needed to connect the hot stream 7 and the cold utility 13 to achieve heat exchange and reduce the temperature of the hot stream 7 to the target temperature; the amount of cold utility 13 required in operation cycle B is relatively small.

[0079] The present invention realizes the cross-cycle use of chemical waste heat by setting an energy storage unit in the waste heat utilization of the industrial system. The heat of the hot stream 7 in the operation cycle A is stored in the energy storage unit 15 through the charging pipeline 19, and the use of the cold public engineering 13 is completely eliminated or reduced while meeting the target temperature of the hot stream 7; when the system runs to the operation cycle B, the heat is released to the cold stream 8 and the cold stream 9 through the energy release pipeline 20, and the use of the hot public engineering 14 is completely eliminated or reduced while meeting the target temperature of the cold stream 8 and the cold stream 9, thereby realizing the efficient utilization of waste heat energy. The energy storage unit 15 includes multiple layers of energy storage materials 16, and electric valves 17 and electric valves 18 are arranged between each layer of energy storage materials. The heat storage amount of the energy storage unit can be adjusted by the electric valve 17 according to the different energy storage requirements of each cycle.

[0080] An industrial waste heat utilization system and design method including an energy storage unit described in the present invention can be manufactured and used in the field of waste heat recovery. The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, advantages, effects, etc. mentioned in the present application are only examples and not limitations. It cannot be considered that these advantages, advantages, effects, etc. are necessary for each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation. The above details do not limit the present application to the use of the above specific details. The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A design method for an industrial waste heat utilization system including an energy storage unit, comprising: Step 1: Obtain the flow data of the industrial system; Step 2: Set energy targets for each single-cycle industrial system; Step 3: Based on the energy characteristics of each stream of the industrial system in a single cycle, the industrial system is divided into blocks and the heat exchange network structure corresponding to the industrial system in the cycle is calculated; Step 4: Integrate the multi-cycle heat exchange network structure and energy target, determine the installation location of the energy storage unit, and obtain the industrial system heat exchange network including the energy storage unit; The step 3 further comprises: Step 301: Based on the energy composite curve corresponding to each cycle obtained in step 2, the energy composite curve in each cycle is divided into blocks, and the block division is based on the slope of the composite curve of the cold and hot streams, and the composite curves with similar slopes are merged into one block; the boundary enthalpy and boundary temperature of each block after the block division are obtained, and the heat exchange network modeling and calculation are carried out for the industrial system of each block, and a mixed integer nonlinear superstructure heat exchange network model is constructed; Step 302, combining the heat exchange network structures designed for each block in the same cycle to construct a single-cycle heat exchange network; Step 3 also includes: Step 303: re-determine the installation location, actual usage and / or temperature range of the utilities required for the heat exchange network in each cycle according to the heat exchange network design.

2. The design method of an industrial waste heat utilization system including an energy storage unit according to claim 1, characterized in that: The stream data of the industrial system in step 1 at least include the initial temperature, target temperature, specific heat capacity and / or flow rate of each stream.

3. The design method of an industrial waste heat utilization system including an energy storage unit according to claim 1, characterized in that: The step 2 of formulating energy targets for each single-cycle industrial system further includes: Based on the industrial system flow data obtained in step 1, draw the energy composite curve corresponding to each cycle, and determine the pinch point temperature of each cycle through the energy composite curve; and calculate the theoretical utility consumption required for the industrial system in each cycle; integrate the pinch point temperature and theoretical utility consumption of each cycle to obtain a multi-pinch point temperature distribution diagram and the maximum and minimum theoretical utility consumption required in each cycle.

4. The design method of an industrial waste heat utilization system including an energy storage unit according to claim 1, characterized in that: The step 4 further comprises: Step 401, based on the obtained overall design of each periodic heat exchange network and the utility engineering information, determine the energy difference existing in each block of the heat exchange network of different periods; Step 402: Based on the energy difference and the temperature range, determine the possibility of direct heat exchange of utilities in different periods. Step 403: When the minimum heat transfer temperature difference is met, the utilities of different periods of the industrial system directly exchange heat; when the minimum heat transfer temperature difference is not met, return to step 3; Step 404: Based on the industrial system operation cycle, heat exchange network blocks and energy difference information, determine the installation location, capacity and cost of the energy storage unit through mathematical modeling; Step 405, economic test, when the economic requirements are met, an industrial waste heat utilization system including an energy storage unit is obtained, when the economic requirements are not met, return to step 403, and reconfigure the direct heat exchange of the utilities in different periods of the industrial system.

5. The design method of an industrial waste heat utilization system including an energy storage unit according to claim 4, characterized in that: The step 403 further includes: using the extra waste heat resources in the previous operation cycle to charge the energy storage unit, and / or using the charged energy storage unit to release heat to the heat exchange network in the subsequent operation cycle.

Images