CN-122015213-A - Phase change energy storage device for adjusting energy efficiency of air conditioning system and control method thereof

CN122015213ACN 122015213 ACN122015213 ACN 122015213ACN-122015213-A

Abstract

The invention relates to the technical field of air conditioning systems, and particularly discloses a phase change energy storage device for adjusting energy efficiency of an air conditioning system and a control method thereof, wherein the device comprises a hollowed-out energy storage cabinet body, core components such as a phase change energy storage unit, a plate heat exchanger and the like, a heat exchange coil adopts a double-spiral cross flow structure and is provided with needle-shaped ribs, and a flexible optical fiber sensor is integrated to monitor the state of a phase change material; the control method is based on an LSTM cold load prediction model, combines dynamic electricity price and carbon price to make a multi-element optimization decision, takes the load rate of a water chilling unit as a core, sets three operation modes of cold accumulation, cold release and low carbon, and realizes intelligent switching. The invention solves the problems of low integration level, single control target and insufficient mode flexibility in the prior art, and realizes multi-target collaborative optimization of energy efficiency, cost and carbon emission reduction of an air conditioning system.

Inventors

DU XIJUN
ZHONG KAIQIANG
WU SHAORU
GAN FENGHUA
WANG XIAOPO
FU JINGHANG
HE CHENG
LIU HONGZHAN
ZHANG SHULI
LU AIMIN
WANG ZENGJIE
HAN RUIDONG

Assignees

中铁建设集团有限公司

Dates

Publication Date: 20260512
Application Date: 20260317

Claims (10)

1. The utility model provides a phase change energy storage device for adjusting air conditioning system efficiency, its characterized in that includes the energy storage cabinet body of fretwork, install phase change energy storage unit, plate heat exchanger, circulating water pump, intelligent control unit in the energy storage cabinet body, wherein phase change material has been filled in the casing of phase change energy storage unit, the submergence has heat exchange coil in the phase change material, the mouth of pipe of heat exchange coil one end is through electric three-way valve one, pipeline one connect the export of plate heat exchanger primary side, the mouth of pipe of the other end is through electric three-way valve two, pipeline two connect the entry of plate heat exchanger primary side, circulating water pump connect in on the pipeline two, electric three-way valve one with circulating water pump all is electrically connected intelligent control unit, intelligent control unit still electrically connects temperature sensor, flow sensor, power sensor, wherein temperature sensor is used for gathering chilled water supply return water temperature, chilled water supply return temperature, phase change material real-time temperature, chilled water flow sensor is used for gathering water real-time flow, power consumption real-time cooling water flow, power consumption of cooling water for each cooling water pump/cooling tower set.
2. The phase change energy storage device for adjusting energy efficiency of an air conditioning system according to claim 1, wherein the heat exchange coil is of a double spiral cross flow structure, and needle-shaped ribs are provided on an inner wall of the heat exchange coil.
3. The phase-change energy storage device for adjusting energy efficiency of an air conditioning system according to claim 1, wherein a flexible optical fiber sensor is integrated in a shell of the phase-change energy storage module and is used for monitoring a phase-change state, temperature distribution uniformity and aging degree of a phase-change material in real time, and the flexible optical fiber sensor is electrically connected with the intelligent control unit.
4. A control method for adjusting energy efficiency of an air conditioning system, wherein the air conditioning system comprises a water chiller, a cooling tower and the phase change energy storage device according to any one of claims 1-3, and the method is applied to the phase change energy storage device connected with a chilled water loop and a cooling water loop of the air conditioning system, and is characterized by comprising the following steps: s1, supplying power to an air conditioning system, initializing a temperature sensor, a flow sensor and a power sensor, starting and loading historical operation data and an LSTM cold load prediction model by an intelligent control unit, entering a circulation monitoring state, and continuously carrying out multi-objective optimization decision by combining dynamic electricity price and regional carbon price parameters in the monitoring process; s2, the intelligent control unit collects the temperature of chilled water supply and return water, the temperature of cooling water, the temperature of phase change materials and the power consumption parameters of an air conditioning system in real time, calculates the real-time load rate of the water chilling unit, and simultaneously updates a future 24-hour cold load prediction model by combining weather forecast and building personnel density data; S3, taking the real-time load rate of the water chilling unit as a core judgment basis, and simultaneously, independently checking low-carbon operation conditions and performing trigger judgment of different modes: S31, firstly, independently checking low-carbon operation conditions, and if all the low-carbon operation conditions pass, immediately calling LSTM future 24-hour cold load prediction data by the intelligent control unit, and carrying out high-load look-ahead prediction and multi-target income balance; s311, no subsequent high load demand exists, or the cold accumulation gain is lower than the low carbon gain, the low carbon operation mode is directly triggered, and the condition inspection and triggering processes of the cold accumulation mode and the cold release mode are skipped; S312, if the subsequent high-load demand exists and the cold accumulation benefit is obviously higher than the low-carbon benefit, the low-carbon mode is not triggered temporarily, a condition inspection link of the cold accumulation mode is entered, and whether the cold accumulation is performed is judged according to the logic of the cold accumulation mode; The low-carbon running condition comprises that the instantaneous cold load demand of the building is lower than 30% of the rated capacity of a water chilling unit, the residual cold capacity of the phase-change energy storage module is enough to cover the total cold load of a predicted period, the average temperature of the phase-change material is lower than the phase-change point temperature of the phase-change material by more than 3 ℃, and the total cold load of the predicted period is not more than 80% of the residual cold capacity of the module; s32, judging according to the load rate; S321, if the load rate is less than 50%, entering a cold storage condition checking link, wherein the checking condition comprises whether the cold storage condition is in a grid valley period, whether an air conditioning system real-time COP (coefficient of performance) has an optimized space, whether a phase change material has cold storage capacity, triggering a cold storage mode when all the conditions are met, and maintaining a conventional/current operation mode when any condition is not met; S322, if the load rate is more than 80%, entering a cooling condition checking link, wherein the checking condition comprises the steps of predicting whether the COP of an air conditioning system after cooling can be improved by more than 5%, whether the phase-change energy storage module has available cooling capacity and whether the phase-change material has cooling capacity, triggering a cooling mode when all the conditions are met, and maintaining a conventional/current running mode when any condition is not met; S323, if the load rate is in a high-efficiency interval of 50% -80%, directly maintaining a conventional/current operation mode; S4, executing corresponding control operation after entering a corresponding operation mode: S41, a cold accumulation mode, namely an intelligent control unit outputs a signal to adjust an electric three-way valve, so that part of chilled water flows through a phase change energy storage module, the flow rate of the chilled water entering the phase change energy storage module is dynamically adjusted by adopting a fuzzy PID control strategy, and the temperature difference between an inlet and an outlet of the phase change energy storage module is stabilized in an optimal interval of 3-5 ℃, so that efficient cold accumulation is realized; S42, in a cooling mode, an intelligent control unit outputs a signal to start an integrated circulating water pump, and switches an electric three-way valve to a plate heat exchanger passage, so that the cooling capacity stored by the phase-change energy storage module is indirectly cooled by the plate heat exchanger to enter cooling water of a condenser of a chiller, and the condensation temperature is reduced to improve the COP of an air conditioning system; s43, in a low-carbon operation mode, the intelligent control unit outputs signals to stop the water chiller, the cooling water pump and the cooling tower, only the phase-change energy storage module and the chilled water pump are kept to operate, and the phase-change energy storage module directly supplies cold to the tail end of the air conditioner; S5, continuously judging mode exit conditions in the running process of each mode, if a trigger condition of a higher priority mode appears in the running process, or any exit condition of the current mode is met, immediately exiting the current mode, and re-executing the mode trigger judgment flow of S3: S51, a cold accumulation mode exit condition is that the load rate of the water chilling unit is more than or equal to 50%, or the cold accumulation of the phase change energy storage module is completed, or the low-carbon operation condition in the operation process is checked to pass; S52, the exiting condition of the cooling mode is that the load rate of the water chilling unit is less than or equal to 80 percent, or the available cold energy of the phase-change energy storage module is lower than a set threshold, or the low-carbon operation condition in the operation process is checked to pass; S53, a low-carbon operation mode exit condition is that the average temperature of the phase change material is increased to be higher than the phase change point temperature of the phase change material, or the instantaneous cooling load requirement of an air conditioning system exceeds the cooling capacity of the phase change energy storage module and lasts for more than 5 minutes; and S6, after exiting any mode, the air conditioning system immediately returns to the normal operation mode, and the mode triggering judgment flow of S3 is re-executed, so that the corresponding mode is triggered or the normal operation is maintained according to the real-time working condition.
5. The control method for adjusting energy efficiency of an air conditioning system according to claim 4, wherein the multi-objective optimization decision in step S1 is to construct a collaborative optimization function with the objective of highest energy efficiency, lowest running cost and maximum carbon emission reduction of the air conditioning system as an auxiliary decision basis for triggering and running of each mode.
6. The control method for adjusting energy efficiency of an air conditioning system according to claim 4, wherein the real-time load factor of the chiller in step S2 is calculated by the intelligent control unit according to the ratio of the collected actual cooling capacity to the rated cooling capacity of the chiller.
7. The control method for adjusting energy efficiency of an air conditioning system according to claim 4, wherein the fuzzy PID control strategy in step S41 uses a temperature difference between an inlet and an outlet of the phase-change energy storage module as a core control target, and realizes accurate and stable control of temperature difference by dynamically adjusting chilled water flow through monitoring temperature difference change in real time.
8. The control method for adjusting energy efficiency of an air conditioning system according to claim 4, wherein the step S42 is an intermediate cooling water process, and the COP of the chiller is improved by more than 5% by using the cooled cooling water temperature as a heat exchange effect judgment criterion.
9. The control method for adjusting energy efficiency of an air conditioning system according to claim 4, wherein the exit condition of each mode in step S5 is determined as real-time continuous determination, the intelligent control unit performs threshold comparison and condition verification according to real-time parameters collected by the sensor, and immediately outputs a mode switching signal when the exit condition is satisfied.
10. The control method for adjusting energy efficiency of an air conditioning system according to claim 4, wherein the high load look-ahead prediction in the step S31 is required to be simultaneously satisfied, the LSTM model predicts a high load working condition with a load rate of not less than 80% in the future 12 hours, predicts that the current residual cold capacity of the phase change energy storage unit cannot satisfy the cooling demand under the high load working condition, the average temperature of the current phase change material is not less than 2 ℃ higher than the phase change point temperature thereof, the residual cold storage space is not less than 30% of the total cold storage capacity, predicts no other cold storage window period in the subsequent high load period, the multi-objective profit trade-off is a comprehensive optimization target value of a cold storage priority strategy and a low carbon priority strategy within 24 hours in the future, and if the F value of the cold storage priority strategy is not less than 10%, the cold storage profit is determined to be significantly higher than the low carbon profit.

Description

Phase change energy storage device for adjusting energy efficiency of air conditioning system and control method thereof Technical Field The invention relates to the technical field of air conditioning systems, in particular to a phase change energy storage device for adjusting energy efficiency of an air conditioning system and a control method thereof. Background The phase change energy storage technology is a core technology direction for solving the problem of unmatched load fluctuation and host operation efficiency of an air conditioning system by virtue of excellent characteristics of high energy storage density and isothermal heat absorption and release, and is widely applied to energy saving optimization of a central air conditioning system. The water chiller of the central air conditioning system is used as a core device at the cold source side, the running efficiency of the water chiller is highly related to the load rate, the water chiller can normally run at high efficiency only in a load rate interval of 50% -80%, the actual building cold load is influenced by factors such as personnel density, ambient temperature, use scene and the like to present obvious dynamic fluctuation, the water chiller is frequently in a low-load (< 50%) or high-load (> 80%) working condition, the overall energy efficiency (COP) of the system is greatly attenuated, and meanwhile, the energy consumption and the carbon emission are increased. The phase-change energy storage device is coupled with the central air conditioning system, the load rate of the host is regulated by cold accumulation and cold release of the energy storage unit, which becomes a key means for improving the energy efficiency of the system, but the prior art has a plurality of limitations in the aspects of device integration, control strategy, operation mode and the like, and the high-efficiency cooperative operation of the phase-change energy storage technology and the central air conditioning system is difficult to realize, and the specific defects are as follows: The system integration level is low, the control strategy is extensive, namely the phase change heat accumulator disclosed in the patent CN115540663A improves the heat exchange uniformity through the movable partition plate and the channel, but the design core of the phase change heat accumulator is that the structure of the heat accumulator is optimized, the integral coupling control strategy with a central air conditioner water system is not involved, and the active optimization of the running state of a host is especially lacking. The existing control strategy depends on simple time interval division or load percentage, and cannot achieve accurate matching with a host high-efficiency operation interval. The control objective is single, for example, patent CN114754435B proposes multi-region phase-change air conditioner cooperative control for a high-speed rail station room, but the focus is on balancing of a space temperature field, the control logic depends on temperature difference among regions, and the control logic is not optimized for the whole energy efficiency (COP) of the system, and cannot be directly applied to a traditional central air conditioning system taking a water chiller unit as a core. The mode flexibility is insufficient, and the operation modes of most existing systems are relatively fixed, so that the complex and changeable actual load demands are difficult to deal with. Particularly, the efficiency of the water chilling unit is drastically reduced under low-load working conditions such as night or transitional seasons, but the prior art lacks a low-carbon operation mode in which the main machine is completely shut down to maximize energy saving on the premise of ensuring cooling. Disclosure of Invention In view of the above technical problems in the related art, the present invention provides a phase change energy storage device for adjusting energy efficiency of an air conditioning system and a control method thereof, which can solve the above problems. In order to achieve the technical purpose, the technical scheme of the invention is realized as follows: The utility model provides a phase change energy storage device for adjusting air conditioning system efficiency, includes the energy storage cabinet body of fretwork, install phase change energy storage unit, plate heat exchanger, circulating water pump, intelligent control unit in the energy storage cabinet body, wherein phase change material has been filled in the casing of phase change energy storage unit, the submergence has heat exchange coil in the phase change material, the mouth of pipe of heat exchange coil one end is through electronic three-way valve one, pipeline one connect the export of plate heat exchanger primary side, the mouth of pipe of the other end is through electronic three-way valve two, pipeline two connect the entry of plate heat exchanger primary side, circulating water pump connect