CN115373368A - Online real-time energy efficiency monitoring and evaluating system for central air-conditioning refrigeration system - Google Patents
Online real-time energy efficiency monitoring and evaluating system for central air-conditioning refrigeration system Download PDFInfo
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Abstract
The invention relates to the technical field of a central air-conditioning refrigeration system, in particular to an online real-time energy efficiency monitoring and evaluating system of the central air-conditioning refrigeration system, which comprises a water chilling unit evaluating module, a cooling tower evaluating module, a water pump evaluating module and a control system evaluating module; the water chilling unit evaluation module is used for acquiring a theoretical energy efficiency value of the host, comparing the theoretical energy efficiency value with an actually-operated energy efficiency value and judging whether the energy efficiency reaches the standard or not; the cooling tower evaluation module is used for calculating the actual approximation degree of the cooling tower, comparing the actual approximation degree with the theoretical approximation degree and judging whether the energy efficiency reaches the standard or not; the water pump evaluation module is used for calculating the operation efficiency of the water pump, comparing the operation efficiency with the theoretical efficiency and judging whether the energy efficiency reaches the standard; and the control system evaluation module is used for calculating to obtain an operation temperature difference real-time value of the chilled water and the cooling water system, comparing the real-time value with a theoretical value and judging whether the energy efficiency reaches the standard or not.
Description
Technical Field
The invention relates to the technical field of central air-conditioning refrigeration systems, in particular to an on-line real-time energy efficiency monitoring and evaluating system for a central air-conditioning refrigeration system.
Background
The energy consumption of the central air-conditioning system in China is huge, the central air-conditioning system is widely applied to large civil and industrial buildings such as hotels, restaurants, office buildings, subways, factories and the like, and the energy consumption of the central air-conditioning system accounts for about 40 to 60 percent of the total energy consumption of the whole building and is more than 5 to 10 times of the energy consumption of common residential units. Taking a subway air conditioning system as an example: the energy consumption of the subway air conditioning system is only lower than the traction energy consumption of a train, and accounts for about 40% of the energy consumption of the whole air conditioning system, so that the energy consumption is quite remarkable.
The control system of the central air-conditioning refrigeration system in China is difficult to ensure the optimal energy consumption of the system, and the air-conditioning refrigeration system is a multi-equipment and multi-system integrated system and mainly comprises a cold and heat source host, a water pump, a cooling tower and other equipment. The devices and the systems are mutually influenced, restricted and coupled. At present, the control system of the air-conditioning refrigeration system is in independent control of each device and each system, and the situation that each device is in the best energy efficiency level is difficult to guarantee. Meanwhile, because the devices are mutually influenced and coupled and are in dynamic balance, the energy consumption of a single device is the lowest in the conventional control system, and the energy efficiency of the whole system is difficult to realize to be optimal, so that an on-line real-time energy efficiency monitoring and evaluating system of a central air-conditioning refrigeration system is provided.
Disclosure of Invention
The invention aims to solve the defects in the prior art and provides an on-line real-time energy efficiency monitoring and evaluating system for a refrigeration system of a central air conditioner.
In order to achieve the purpose, the invention adopts the following technical scheme:
an on-line real-time energy efficiency monitoring and evaluating system of a central air-conditioning refrigeration system comprises a water chilling unit evaluating module, a cooling tower evaluating module, a water pump evaluating module and a control system evaluating module;
the water chilling unit evaluation module is used for acquiring a theoretical energy efficiency value of the host, comparing the theoretical energy efficiency value with an actually-operated energy efficiency value and judging whether the energy efficiency reaches the standard or not;
the cooling tower evaluation module is used for calculating the actual approximation degree of the cooling tower, comparing the actual approximation degree with the theoretical approximation degree and judging whether the energy efficiency reaches the standard or not;
the water pump evaluation module is used for calculating the operating efficiency of the water pump, comparing the operating efficiency with the theoretical efficiency and judging whether the energy efficiency reaches the standard;
and the control system evaluation module is used for calculating to obtain an operation temperature difference real-time value of the chilled water and the cooling water system, comparing the real-time value with a theoretical value and judging whether the energy efficiency reaches the standard or not.
Preferably, the energy efficiency evaluation method of the water chilling unit evaluation module is as follows:
establishing an evaluation model: the manufacturer adopts a laboratory to test different working condition combinations of the cold unit or model selection parameter calculation software of the manufacturer to obtain an energy efficiency ratio COP value, and an evaluation model is established according to the energy efficiency ratio COP value;
establishing a monitoring system: the system comprises a water chilling unit, a water inlet pipe and a water outlet pipe of chilled water of the water chilling unit, wherein temperature sensors are arranged on the water inlet pipe and the water outlet pipe of the chilled water, and a flow sensor is arranged on the water outlet pipe of the chilled water;
data acquisition and calculation: collecting temperature and flow data required by evaluation, and calculating actual load factor PLR and actual energy efficiency value COP according to the collected data z2 ；
Calculating the theoretical energy efficiency value of the host: introducing the outlet water temperature of the chilled water, the inlet water temperature of the cooling water and the load rate PLR into an evaluation model, and calculating to obtain a theoretical energy efficiency value of the hostCOP z1 ；
And (3) energy efficiency evaluation: when actual energy value is COP z2 More than or equal to the theoretical effective value COP of the host z1 If the energy efficiency of the host operation reaches the standard; when actual energy value is COP z2 <Theoretical host coefficient of performance (COP) z1 And the operation energy efficiency of the host is not up to the standard.
Further, the load factor PLR = actual refrigerating capacity/standard refrigerating capacity, and the actual energy value COP z2 And the actual refrigerating capacity of the water chilling unit is calculated according to the inlet and outlet water temperatures of the chilled water and the flow rate of the chilled water.
Further, the energy efficiency evaluation method of the cooling tower evaluation module is as follows:
establishing a monitoring system: temperature sensors are arranged on a water inlet pipe and a water outlet pipe of the cooling tower, a flow sensor is arranged on the water outlet pipe of the cooling tower, and a temperature and humidity sensor is arranged near the cooling tower and is used as an outdoor air direction station;
data acquisition and calculation: measuring the outdoor wet bulb temperature and the cooling tower outlet water temperature by adopting an outdoor temperature and humidity external sensor and a temperature sensor on a cooling water pipeline, and calculating the actual approach degree of the cooling tower;
and (3) energy efficiency evaluation: and comparing the actual approximation degree with the theoretical approximation degree, and when the actual approximation degree is less than or equal to the theoretical approximation degree, determining that the operating energy efficiency of the cooling tower reaches the standard.
Further, the energy efficiency evaluation method of the water pump evaluation module is as follows:
establishing an evaluation model: obtaining an operating efficiency model of the water pump under the operating state under the rated working condition according to a model selection report provided by a water pump manufacturer;
establishing a monitoring system: pressure sensors are arranged on a water inlet pipe and a water outlet pipe of the water pump, and a flow sensor is arranged on the water inlet pipe;
data acquisition and calculation: acquiring current lift and current flow data of the water pump, and calculating the actual operating efficiency of the water pump;
and (3) energy efficiency evaluation: when the actual efficiency of the water pump operation is not more than the theoretical efficiency, the water pump operation energy efficiency is considered to reach the standard.
Further, the modeling method of the operation efficiency model comprises the following steps: the method comprises the steps of fitting an efficiency eta-flow Q performance curve provided by a water pump manufacturer by a least square method, establishing an operation efficiency model on the basis of the efficiency eta-flow Q performance curve, namely obtaining efficiency values under different flows by using the eta-Q performance curve provided by the manufacturer, then performing approximate fitting by the least square method to finally obtain an approximate function to express a functional relation between eta-Q, and establishing a data model by using the functional relation.
Further, the energy efficiency evaluation method of the control system evaluation module is as follows:
establishing a monitoring system: electric energy meters are arranged on the cooling tower, the water pump, the fan and the air conditioner;
data acquisition and calculation: collecting the temperature values measured by the chilled water and cooling water system inlet and outlet temperature sensors, and calculating to obtain the running temperature difference of the chilled water and cooling water systems;
and (3) energy efficiency evaluation: when the real-time value of the operation temperature difference of the chilled water and the cooling water system is less than 0.5 ℃ compared with the theoretical deviation value, the energy efficiency of the control system is considered to reach the standard;
further, the energy efficiency evaluation index of the control system further comprises debugging efficiency and heat balance rate, and if the debugging efficiency is less than 25% and-10% < the heat balance rate is less than 10%, the energy efficiency is considered to reach the standard.
The invention provides an on-line real-time energy efficiency monitoring and evaluating system for a central air-conditioning refrigeration system, which has the beneficial effects that: the system can monitor all main equipment and the whole central air-conditioning refrigeration system on line, obtain the corresponding energy consumption parameters and the working states of the main influence parameters in real time, and further analyze the corresponding working states to ensure that the central air-conditioning refrigeration system works in the optimal state.
The energy-saving effect is obvious: the system can ensure that all main equipment and the whole system work in the optimal state, thereby realizing remarkable energy-saving effect. By taking a standard subway station as an example, the system can improve the energy efficiency of the air conditioning system by about 30 percent and realize the high energy efficiency ratio of more than 5.0.
The applicability is wide: the system can be applied to equipment debugging in the construction process, equipment operation monitoring in the operation process and debugging and operation of application equipment system transformation. The air conditioner can be widely applied to civil use, industrial buildings and central air conditioning systems of rail transit engineering, and has wide applicability.
The cost is low: the system can be used as an independent module to be directly arranged in an air conditioner control system, and the manufacturing cost and the cost are very low compared with the energy-saving effect.
Drawings
Fig. 1 is a frame diagram of an on-line real-time energy efficiency monitoring and evaluating system for a refrigeration system of a central air conditioner, which is provided by the invention;
fig. 2 is a schematic diagram of monitoring and evaluating a water chilling unit of an on-line real-time energy efficiency monitoring and evaluating system of a central air-conditioning refrigeration system according to the present invention;
FIG. 3 is a schematic view of monitoring and evaluating a cooling tower of an on-line real-time energy efficiency monitoring and evaluating system for a refrigeration system of a central air conditioner according to the present invention;
FIG. 4 is a schematic diagram of water pump monitoring and evaluation of an on-line real-time energy efficiency monitoring and evaluating system of a refrigeration system of a central air conditioner according to the present invention;
fig. 5 is a schematic diagram of monitoring and evaluating a control system of an on-line real-time energy efficiency monitoring and evaluating system of a central air-conditioning refrigeration system according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Referring to fig. 1-5, an on-line real-time energy efficiency monitoring and evaluating system for a refrigeration system of a central air conditioner comprises a water chilling unit evaluating module, a cooling tower evaluating module, a water pump evaluating module and a control system evaluating module;
the water chilling unit evaluation module is used for acquiring a theoretical energy efficiency value of the host, comparing the theoretical energy efficiency value with an actually-operated energy efficiency value and judging whether the energy efficiency reaches the standard or not;
the cooling tower evaluation module is used for calculating the actual approximation degree of the cooling tower, comparing the actual approximation degree with the theoretical approximation degree and judging whether the energy efficiency reaches the standard or not;
the water pump evaluation module is used for calculating the operation efficiency of the water pump, comparing the operation efficiency with the theoretical efficiency and judging whether the energy efficiency reaches the standard;
and the control system evaluation module is used for calculating to obtain an operation temperature difference real-time value of the chilled water and the cooling water system, comparing the real-time value with a theoretical value and judging whether the energy efficiency reaches the standard or not.
The energy efficiency evaluation method of the water chilling unit evaluation module comprises the following steps:
establishing an evaluation model: the COP value of each energy efficiency ratio is obtained by testing different working condition combinations of the water chilling unit in a factory collection laboratory or model selection parameter calculation software of the factory, and an evaluation model is established according to the COP value.
Establishing a monitoring system: setting temperature, flow and pressure sensors at corresponding positions of the system;
and taking the evaluation model as a module of the control system, and placing the evaluation model in a central control system of the control system.
Data acquisition and calculation: collecting temperature and flow data required by evaluation, and calculating actual load factor PLR and actual energy efficiency value COP according to the collected data z2 (ii) a The load factor PLR = actual refrigerating capacity/standard refrigerating capacity, and the actual energy value COP z2 And the actual refrigerating capacity of the water chilling unit is calculated according to the inlet and outlet water temperatures of the chilled water and the flow rate of the chilled water.
Calculating a theoretical energy effective value of the host (calculating an optimal COPz1 value of corresponding working conditions): introducing the outlet water temperature t1 of the chilled water, the inlet water temperature t3 of the cooling water and the load factor PLR into an evaluation model, and calculating to obtain the theoretical effective value COP of the host z1 ；
And (3) energy efficiency evaluation: when actual energy value is COP z2 COP (coefficient of performance) not less than the theoretical energy value of the main engine z1 If so, the operation energy efficiency of the host reaches the standard; when actual energy value is COP z2 <Theoretical host coefficient of performance (COP) z1 And the operation energy efficiency of the host is not up to the standard.
And (3) evaluating the model:
a. influencing the parameter
The energy efficiency COP (energy efficiency ratio: refrigerating capacity/power consumption) performance of the water chilling unit is closely related to three parameters of the load factor PLR (actual load/standard condition load of a main engine), the water outlet temperature t1 (mainly affecting evaporation temperature) of chilled water and the water inlet temperature t3 (mainly affecting condensation temperature) of cooling water. Therefore, the main COP evaluation mathematical model is established around three variable parameters of the load factor PLR of the water chilling unit, the outlet water temperature t1 of the chilled water and the inlet water temperature t3 of the cooling water.
COP＝f(PLR，t1，t3)
b. Influence parameter range and gradient
Under different operating conditions, the COP values of the water chilling unit are different. Therefore, the theoretical COP value of the water chilling unit under all operating conditions needs to be analyzed firstly when the assessment quantitative index of the COP of the water chilling unit is established.
According to the meteorological characteristics and load characteristics of regions, the running working conditions of the water chilling unit are analyzed, the fluctuation range of the freezing water outlet temperature is 6-12 ℃, the fluctuation range of the cooling water inlet temperature is 22-32 ℃, the fluctuation range of the load rate PLR is 20-100%, and the fluctuation ranges of the freezing water outlet temperature, the cooling water inlet temperature and the load rate can already cover all the running working conditions of the air conditioning system.
The load rate PLR is graded by 10 percent and ranges from 30 percent to 100 percent; the temperature t1 of the outlet water of the chilled water takes 1 ℃ as the gradient and ranges from 6 ℃ to 15 ℃; the water inlet temperature t3 of the cooling water takes 2 ℃ as gradient and ranges from 22 ℃ to 32 ℃.
c. Mathematical model
Firstly, respectively establishing a data set by the load factor PLR and the energy efficiency ratio COP of the unit according to the outlet water temperature t1 of chilled water (gradient at every 1 ℃) and the inlet water temperature t3 of cooling water (gradient at every 2 ℃), wherein the data set is an evaluation mathematical model.
Example (c): when t3=30 ℃ and t1=7 ℃, the corresponding data set is as follows:
when t3=30 ℃ and t1=8 ℃, the corresponding data set is as follows:
d. energy efficiency ratio COP estimation value acquisition method
The method is mainly obtained by two schemes of factory actual measurement or theoretical calculation, namely, a factory obtains COP values of all energy efficiency ratios required in c by using a laboratory to test different working condition combinations of the refrigerator or model selection parameter calculation software of the factory, and an evaluation model is established according to the COP values.
e. Acquisition of actual operating parameters
And (3) obtaining the actual chilled water inlet (t 2), outlet water temperature (t 1), chilled water flow rate Qc, cooling water inlet temperature (t 3) and actual power consumption W of the water chilling unit through a monitoring system in the actual operation process.
The actual refrigerating capacity of the water chilling unit can be calculated by the inlet (t 2) and outlet (t 1) temperature of the chilled water and the flow rate Qc of the chilled water, and the ratio of the actual refrigerating capacity to the standard refrigerating capacity of the water chilling unit is the PLR value. The ratio of the actual cooling capacity to the actual power consumption W is the actual energy efficiency ratio COPz2.
f. Evaluation of
Introducing the outlet water temperature (t 1) of the chilled water, the inlet water temperature of the chilled water and the load factor PLR into an evaluation model to obtain the theoretical effective value COP of the host under the working condition z1 Then the actual COP z2 And comparing with it. When actual energy value is COP z2 COP (coefficient of performance) not less than the theoretical energy value of the main engine z1 If so, the operation energy efficiency of the host reaches the standard; when actual energy value is COP z2 <Theoretical host coefficient of performance (COP) z1 And the operation energy efficiency of the host does not reach the standard.
The energy efficiency evaluation method of the cooling tower evaluation module is as follows;
establishing an evaluation model: and inputting the theoretical approximation degree (design working condition) of the cooling tower.
Establishing a monitoring system: and sensors for temperature, humidity, flow and the like are arranged at corresponding positions of the system.
Data acquisition and calculation; collecting an outdoor temperature and humidity sensor, wherein the temperature sensor on a cooling water pipeline measures the outdoor wet bulb temperature ts and the cooling tower outlet water temperature t3;
and calculating the actual approaching degree delta t3' = t3-ts of the cooling tower.
And (3) energy efficiency evaluation: comparing the actual approximation degree delta t3' with the theoretical approximation degree delta t3 (design condition);
when Δ t3' (actual) ≦ Δ t3 (the design condition), the energy efficiency is considered to be up to standard.
The evaluation model of the cooling tower is simple, and only the measured approximation degree of the cooling tower is required to be not greater than the theoretical approximation degree (design working condition) under the rated operating working condition. Under the condition of variable frequency operation working condition under partial load, the approximation degree of the cooling tower is not larger than the theoretical approximation degree value given by a manufacturer.
And an outdoor temperature and humidity external sensor and a temperature sensor on a cooling water pipeline are adopted to measure the outdoor wet bulb temperature ts and the cooling tower outlet water temperature t3. The actual approximation degree delta t3' = t3-ts of the cooling tower is calculated and compared with the theoretical approximation degree delta t3 (design condition). When Δ t3 (actual) is less than Δ t3 (design condition), the energy efficiency is considered to be up to standard. Otherwise, increasing the wind power frequency or cleaning the cooling tower.
The energy efficiency evaluation method of the water pump evaluation module comprises the following steps:
establishing an evaluation model: and obtaining an operation efficiency model of the water pump in a transportation state under the rated working condition according to a model selection report provided by a water pump manufacturer.
Establishing a monitoring system: the corresponding position of the system is provided with a temperature sensor, a humidity sensor, a flow sensor and the like
Data acquisition and calculation: acquiring current lift and current flow data of a water pump;
and calculating to obtain the output power (shaft power) of the water pump, measuring according to a calculation electric meter to obtain the input power of the operation of the water pump, wherein the ratio of the output power to the input power is the actual efficiency of the operation of the water pump.
And (3) energy efficiency evaluation: when the real-time efficiency is not higher than the theoretical efficiency, the energy efficiency is considered to reach the standard.
The energy efficiency examination and quantification indexes of the freezing water pump and the cooling water pump which adopt the variable frequency motor to realize variable frequency operation are the operation efficiency under different operation frequencies.
Fitting an eta (efficiency) -Q (flow) performance curve provided by a water pump manufacturer by adopting a least square method, and establishing an operation efficiency model on the basis of the eta (efficiency) -Q (flow) performance curve. The method comprises the steps of obtaining efficiency values under different flow rates by utilizing an eta-Q performance curve provided by a manufacturer, then carrying out approximate fitting by adopting a least square method, finally obtaining an approximate function to express a functional relation between eta and Q, and establishing a data model by utilizing the functional relation.
According to the current lift and the current flow of the water pump, the output power (shaft power) of the water pump can be obtained through calculation, then the input power of the operation of the water pump is obtained through measurement by a measuring electric meter, and the ratio of the output power to the input power is the operation efficiency of the water pump.
When the real-time efficiency is not higher than the theoretical efficiency, the energy efficiency is considered to reach the standard.
The energy efficiency evaluation method of the control system evaluation module comprises the following steps:
establishing a monitoring system: and arranging sensors for temperature, humidity, flow, electric quantity and the like at corresponding positions of the system.
Data acquisition and calculation: collecting data such as temperature, flow, electric quantity of each device and the like of chilled water and cooling water inlet and outlet water;
calculating to obtain parameters such as the running temperature difference (t 2-t 1) of the chilled water, the running temperature difference (t 4-t 3) of the cooling water system, debugging efficiency, heat balance and the like;
and (3) energy efficiency evaluation: when the running temperature difference of the chilled water and the cooling water meets the design temperature difference;
and considering that the energy efficiency reaches the standard.
The main energy efficiency evaluation indexes of the control system comprise the running temperature difference (t 2-t 1) of chilled water, the running temperature difference (t 4-t 3) of a cooling water system, the adaptation efficiency and the heat balance rate.
The operation temperature difference of the chilled water is the design temperature difference, generally 5-7 ℃, and the operation temperature difference of the cooling water is also the design temperature difference, generally 5-7 ℃. It is required that the real-time value of the operating temperature difference between the freezing water system and the cooling water system of the control system should not deviate more than 0.5 degrees from the theoretical value.
Under the condition of frequency conversion working condition, the debugging efficiency of the control system is not more than 25%, and the heat balance rate is not more than +/-5%.
EEROC is the energy efficiency ratio of the refrigerating system, namely:
COP host: actual energy efficiency ratio of the chiller.
Wherein: q2 cooling side thermal load.
Obtaining state parameters such as t1, t2, t3 and t4 through sensors, calculating operation parameters such as a host, a cooling tower and a water pump according to operation conditions: delta t1 and delta t2, and debugging efficiency and heat balance rate;
the method comprises the following steps: real time values of (not being) at (t 1) and (t 2) are not less than theoretical values +/-0.5 DEG C
Debugging efficiency <25% (frequency conversion working condition)
-10% < heat equilibrium rate <10%.
Monitoring and evaluating system configuration scheme:
sensor arrangement
The water inlet pipe and the water outlet pipe of the chilled water of the water chilling unit are provided with temperature sensors; a flow sensor is arranged on the chilled water outlet pipe;
temperature sensors are arranged on the water inlet pipe and the water outlet pipe of the cooling tower; a flow sensor is arranged on a water outlet pipe of the cooling tower;
the water inlet pipe and the water outlet pipe of the water pump are provided with pressure sensors, and the water inlet pipe is provided with a flow sensor;
electric energy meters are arranged on the cooling tower, the water pump, the fan and the air conditioner;
and a temperature and humidity sensor is arranged near the cooling tower to be used as an outdoor weather station.
The system configuration scheme comprises the following steps:
the monitoring and evaluating system can be used as a module of the control system and is arranged in a central control system of the control system, and the monitoring and evaluating system has the following main functions:
the device monitoring function is used for acquiring and displaying the measured value of the sensor and the device parameter of the frequency converter, and the system calculates according to the acquired data and compares the calculated data with the data model; when the deviation value between the actual value and the evaluation value exceeds a specified range, the system automatically gives an alarm.
And the energy consumption counting function is used for uploading energy consumption data acquired by the intelligent electric meter through the communication module and counting the energy consumption data of the corresponding equipment. The energy consumption statistical objects comprise a water chiller, a freezing pump, a cooling pump and a cooling tower.
And measuring power consumption, uploading the measured data and the comparison result of the measuring device to the air conditioner control system, storing the data into a historical database, and periodically printing a report (such as an Excel table) in a common file format.
The remote access function has a data center function, and the remote terminal can access the system server by renting a special network of a communication operator or adopting a wireless webpage browsing mode to obtain real-time operation data and a comparison result of the air-conditioning refrigeration system and display the real-time operation data and the comparison result.
The on-line real-time energy efficiency monitoring and evaluating system for the central air-conditioning refrigeration system has the advantages that all main equipment and the whole system of the central air-conditioning refrigeration system can be monitored on line, corresponding energy consumption parameters and working states of main influence parameters can be obtained in real time, and then the corresponding working states can be obtained through analysis, so that the best working state is guaranteed.
The energy-saving effect is obvious: the system can ensure that all main equipment and the whole system work in the best state, thereby realizing remarkable energy-saving effect. By taking a standard subway station as an example, the system can improve the energy efficiency of the air conditioning system by about 30 percent and realize the high energy efficiency ratio of more than 5.0.
The applicability is wide: the system can be applied to equipment debugging in the construction process, equipment operation monitoring in the operation process and debugging and operation of application equipment system transformation. The air conditioner can be widely applied to civil use, industrial buildings and central air conditioning systems of rail transit engineering, and has wide applicability.
The cost is low: the system can be used as an independent module to be directly arranged in an air conditioner control system, and the manufacturing cost and the cost are very low compared with the energy-saving effect.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (8)
1. An on-line real-time energy efficiency monitoring and evaluating system of a refrigeration system of a central air conditioner is characterized by comprising a water chilling unit evaluating module, a cooling tower evaluating module, a water pump evaluating module and a control system evaluating module;
the water chilling unit evaluation module is used for acquiring a theoretical energy efficiency value of the host, comparing the theoretical energy efficiency value with an actually-operated energy efficiency value and judging whether the energy efficiency reaches the standard or not;
the cooling tower evaluation module is used for calculating the actual approximation degree of the cooling tower, comparing the actual approximation degree with the theoretical approximation degree and judging whether the energy efficiency reaches the standard;
the water pump evaluation module is used for calculating the operating efficiency of the water pump, comparing the operating efficiency with the theoretical efficiency and judging whether the energy efficiency reaches the standard;
and the control system evaluation module is used for calculating to obtain an operating temperature difference real-time value of the chilled water and the cooling water system, comparing the operating temperature difference real-time value with a theoretical value and judging whether the energy efficiency reaches the standard or not.
2. The system for monitoring and evaluating the energy efficiency of the refrigeration system of the central air conditioner in real time on line according to claim 1, wherein the energy efficiency evaluation method of the water chilling unit evaluation module is as follows:
establishing an evaluation model: the manufacturer adopts a laboratory to test different working condition combinations of the cold unit or model selection parameter calculation software of the manufacturer to obtain an energy efficiency ratio COP value, and an evaluation model is established according to the energy efficiency ratio COP value;
establishing a monitoring system: the system comprises a water chilling unit, a water inlet pipe and a water outlet pipe of chilled water of the water chilling unit, wherein temperature sensors are arranged on the water inlet pipe and the water outlet pipe of the chilled water, and a flow sensor is arranged on the water outlet pipe of the chilled water;
data acquisition and calculation: collecting temperature and flow data required by evaluation, and calculating actual load factor PLR and actual energy efficiency value COP according to the collected data z2 ；
Calculating the theoretical effective value of the host: introducing the outlet water temperature of the chilled water, the inlet water temperature of the cooling water and the load factor PLR into an evaluation model, and calculating to obtain the theoretical energy efficiency value COP of the host z1 ；
And (3) energy efficiency evaluation: when actual energy value is COP z2 COP (coefficient of performance) not less than the theoretical energy value of the main engine z1 If so, the operation energy efficiency of the host reaches the standard; when actual energy value is COP z2 <Theoretical host coefficient of performance (COP) z1 And the operation energy efficiency of the host does not reach the standard.
3. The system as claimed in claim 2, wherein the load factor PLR = actual cooling capacity/standard cooling capacity, and the actual energy factor value COP z2 And the actual refrigerating capacity of the water chilling unit is calculated according to the inlet and outlet water temperatures of the chilled water and the flow rate of the chilled water.
4. The system for monitoring and evaluating the energy efficiency of the refrigeration system of the central air conditioner in real time on line according to claim 2, wherein the energy efficiency evaluation method of the cooling tower evaluation module is as follows:
establishing a monitoring system: temperature sensors are arranged on a water inlet pipe and a water outlet pipe of the cooling tower, a flow sensor is arranged on the water outlet pipe of the cooling tower, and a temperature and humidity sensor is arranged near the cooling tower and is used as an outdoor air direction station;
data acquisition and calculation: measuring the outdoor wet bulb temperature and the cooling tower outlet water temperature by adopting an outdoor temperature and humidity external sensor and a temperature sensor on a cooling water pipeline, and calculating the actual approach degree of the cooling tower;
and (3) energy efficiency evaluation: and comparing the actual approximation degree with the theoretical approximation degree, and when the actual approximation degree is less than or equal to the theoretical approximation degree, determining that the operating energy efficiency of the cooling tower reaches the standard.
5. The system for monitoring and evaluating the energy efficiency of the refrigeration system of the central air conditioner in real time on line according to claim 4, wherein the energy efficiency evaluation method of the water pump evaluation module is as follows:
establishing an evaluation model: obtaining an operating efficiency model of the water pump under the operating state under the rated working condition according to a model selection report provided by a water pump manufacturer;
establishing a monitoring system: pressure sensors are arranged on a water inlet pipe and a water outlet pipe of the water pump, and a flow sensor is arranged on the water inlet pipe;
data acquisition and calculation: acquiring current lift and current flow data of the water pump, and calculating the actual operating efficiency of the water pump;
and (3) energy efficiency evaluation: when the actual efficiency of the operation of the water pump is not more than the theoretical efficiency, the operation energy efficiency of the water pump is considered to reach the standard.
6. The system for monitoring and evaluating the on-line real-time energy efficiency of the refrigeration system of the central air conditioner according to claim 5, wherein the modeling method of the operation efficiency model comprises the following steps: the method comprises the steps of fitting an efficiency eta-flow Q performance curve provided by a water pump manufacturer by a least square method, establishing an operation efficiency model on the basis of the efficiency eta-flow Q performance curve, namely obtaining efficiency values under different flows by using the eta-Q performance curve provided by the manufacturer, then performing approximate fitting by the least square method to finally obtain an approximate function to express a functional relation between eta-Q, and establishing a data model by using the functional relation.
7. The system for monitoring and evaluating the energy efficiency of the refrigeration system of the central air conditioner in real time on line according to claim 5, wherein the energy efficiency evaluation method of the control system evaluation module is as follows:
establishing a monitoring system: electric energy meters are arranged on the cooling tower, the water pump, the fan and the air conditioner;
data acquisition and calculation: collecting the temperature values measured by a chilled water and cooling water system inlet and outlet temperature sensor, and calculating to obtain the operating temperature difference of the chilled water and cooling water system;
and (3) energy efficiency evaluation: and when the real-time values of the running temperature difference of the chilled water and the cooling water system are less than 0.5 ℃ compared with the theoretical deviation value, the energy efficiency of the control system is considered to reach the standard.
8. The system of claim 7, wherein the energy efficiency assessment indicators of the control system further comprise a debugging efficiency and a thermal balance rate, and the energy efficiency is considered to be up to standard if the debugging efficiency is less than 25% and-10% < thermal balance rate <10%.
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