CN103453620B - Based on efficiency test and appraisal and the air-conditioning system of optimal control and method thereof - Google Patents

Abstract

The present invention relates to the test and appraisal of air-conditioning system efficiency and control field, aim to provide a kind of based on efficiency test and appraisal and the air-conditioning system of optimal control and method thereof.The new air temperature sensor of this system, return air temperature sensor, return air humidity sensor, air flow rate sensor, supply water temperature sensor are connected to PLC by the input of rack, and PLC is connected to motor, the electronic dynamic flow balanced valve, newly air-valve and air returning valve of air-conditioner set blower fan by output.The present invention installs intelligent valve, using chilled water supply water temperature, chilled water pressure of supply water, outdoor temperature and end switch signal as input and output point in chilled water system and air conditioning terminal; Using each signal and the flow communication point as intelligent valve MODBUS, calculate the energy efficiency coefficient of each system according to assessment method, then in control device, be optimized analysis, change Based Intelligent Control data, the efficiency of system is increased substantially, thus reaches energy-saving and cost-reducing effect.

Description

Based on efficiency test and appraisal and the air-conditioning system of optimal control and method thereof

Technical field

The present invention relates to the test and appraisal of air-conditioning system efficiency and control field.More particularly, the present invention relates to based on efficiency test and appraisal and the air-conditioning system of optimal control and method thereof.

Background technology

Central air-conditioning is the main energy consuming part of modern architecture.According to statistics, the power consumption of central air-conditioning accounts for more than 70% of all kinds of mansions total electricity consumption, the operation and the time of central air conditioning equipment 97% fluctuates below 70% load, and actual air conditioner load on average only has about 50% of capacity of equipment, thus there is the phenomenon of " low load with strong power ", cause huge waste.And during operation of air conditioner, each motor is fixed on full speed running under power frequency state all for a long time, the flow of recirculated water is then regulated by choke valve and by-passing valve, be difficult to the real-time matching realizing discharge and refrigerating capacity, cause water system to be in the high energy consumption running status of " large discharge, the little temperature difference " for a long time, and the COP of refrigeration unit is declined.So need to carry out Energy Saving Control to reduce energy consumption to traditional central air-conditioning, improving energy efficiency coefficient.In today that energy problem becomes increasingly conspicuous, the energy-saving and cost-reducing of field of air conditioning is had great significance.

Summary of the invention

The technical problem to be solved in the present invention is, overcomes deficiency of the prior art, provides a kind of based on efficiency test and appraisal and the air-conditioning system of optimal control and method thereof.

For technical solution problem, solution of the present invention is:

There is provided a kind of based on the air-conditioning system of efficiency test and appraisal with optimal control, comprise the rack that PLC, input and output are housed, this device also comprises:

Fresh wind tube is equipped with new air temperature sensor and new air-valve; Backwind tube is equipped with return air temperature sensor, return air humidity sensor and air returning valve; Ajutage is equipped with air flow rate sensor; Establish filter in air main, show cold/heater and air-conditioner set blower fan; The feed pipe showing cold/heater is equipped with supply water temperature sensor, return pipe is equipped with electronic type dynamic equilibrium flow control valve; Described new air temperature sensor, return air temperature sensor, return air humidity sensor, air flow rate sensor, supply water temperature sensor are connected to PLC by the input of rack, and PLC is connected to motor, the electronic dynamic flow balanced valve, newly air-valve and air returning valve of air-conditioner set blower fan by output;

N group fan coil is installed between chilled water feed pipe and chilled water return pipe, between fan coil and chilled water return pipe, establishes electric two-way valve; Intelligent valve is established at chilled water return pipe end; Mounting temperature sensor and pressure sensor on chilled water feed pipe, outdoor mounted temperature sensor, each temperature sensor and pressure sensor and fan coil switching signal are connected to PLC through cable by the input of rack, and PLC is connected with described intelligent valve with input through output in the lump by holding wire.

In the present invention, be also equipped with in described rack: relay, power supply, supply socket, transformer, abs, display screen and communication interface; Wherein, power supply, supply socket, abs, transformer connect successively, and transformer is connected to each equipment of interior of equipment cabinet to realize power supply; PLC is connected with display screen with communication interface respectively.

Invention further provides the efficiency assessment method being applied to front described air-conditioning system, comprise and the energy efficiency coefficient of handpiece Water Chilling Units, distributing system, end system and hydrodynamic system is calculated; Be specially:

(1) energy efficiency coefficient of handpiece Water Chilling Units calculates

The energy efficiency coefficient of handpiece Water Chilling Units refers to the refrigerating capacity Q of handpiece Water Chilling Units ₁and the general power N consumed ₁ratio, its computing formula is as follows:

$\mathrm{COP}\_1=\frac{Q_1}{N_1}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{{3600N}_1}$

In formula: COP_1: the energy efficiency coefficient of handpiece Water Chilling Units; Q ₁: refrigerating capacity, the refrigerating capacity that handpiece Water Chilling Units exports, kw; N ₁: the total power input of handpiece Water Chilling Units, kw; ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K;

Wherein N ₁=N ₁₁+ N ₁₂+ N ₁₃, N ₁₁for the electrical power that handpiece Water Chilling Units consumes; N ₁₂for the electrical power of chilled water pump system consumption, comprise No. 1 pump and No. 2 pumps and frequency converter; N ₁₃for the electrical power of cooling water pump system consumption, comprise cooling water pump and blower fan of cooling tower and frequency converter;

(2) energy efficiency coefficient of distributing system calculates

During system cloud gray model, by the refrigerating capacity Q measuring the chilled water pump circulation output obtained ₂with the general power N of its consumption ₂just can obtain the energy efficiency coefficient of distributing system, its computing formula is as follows:

$\mathrm{COP}\_2=\frac{Q_2}{N_2}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{{3600N}_2}$

In formula: COP_2: the energy efficiency coefficient of distributing system; Q ₂: the refrigerating capacity that chilled water pump circulation exports, kw; N ₂: the general power that chilled water pump circulation consumes, kw; ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K;

(3) energy efficiency coefficient of end system calculates

During system cloud gray model, by measuring the refrigerating capacity Q of end-equipment digestion ₃with the power N consumed ₃, just can calculate the energy efficiency coefficient of end system, its computing formula is as follows:

$\mathrm{COP}\_3=\frac{Q_3}{N_3}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{{3600N}_3}$

In formula: COP_3: the energy efficiency coefficient of end system; Q ₃: the refrigerating capacity of end system equipment digestion, kw; N ₃: the general power of end system devices consume, kw, ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K;

Wherein: N ₃=Σ N _{3_i};

N _{3_i}=N _{3i_QdP}+N _{3i_FAN}；

N _{3i_QdP}: hydrodynamic force=discharge × (end differential water pressures+valve differential water pressures);

N _{3i_FAN}: wind-power=blower fan input power;

I refers to i-th end-equipment;

(4) energy efficiency coefficient of hydrodynamic system calculates

During system cloud gray model, obtained the energy efficiency coefficient of hydrodynamic system by the volume flow of recirculated water measured and lift, its computing formula is as follows:

$\mathrm{COP}\_3W=\frac{Q_3}{{N^{\′}}_3}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{Q\·\mathrm{\ΔP}}$

In formula: COP_3W: the energy efficiency coefficient of hydrodynamic system; Q ₃: the refrigerating capacity of end system equipment digestion, kw; N' ₃: the power that pipe network consumes, kw; ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K; Q: the volume flow of recirculated water, m ³/ h; Δ P: the lift of recirculated water, m;

(5) energy efficiency coefficient of whole system calculates

The refrigerating capacity digested by end-equipment, and handpiece Water Chilling Units, end-equipment consume power, calculate the energy efficiency coefficient of whole system, its computing formula is as follows:

$\mathrm{COP}\_S=\frac{Q_3}{N_1+N_3}$

In formula: COP_S: the energy efficiency coefficient of whole system; Q ₃: the refrigerating capacity of end system equipment digestion, kw; N ₁: the total power input of handpiece Water Chilling Units, kw; N ₃: the general power of end system devices consume, kw;

(6) user is by calculating the energy efficiency coefficient obtaining whole air-conditioning system and each subsystem, obtains the evaluation result to air-conditioning system operational energy efficiency with this.

By measuring system operational factor, apply the energy efficiency coefficient that above method just can obtain whole air-conditioning system and subsystem, make the ruuning situation of the clearer understanding system of user's energy.

Compared with prior art, beneficial effect of the present invention is:

Control method of the present invention is install intelligent valve in chilled water system and air conditioning terminal, mounting temperature sensor in water system simultaneously, outdoor also needs mounting temperature sensor, using chilled water supply water temperature, chilled water pressure of supply water, outdoor temperature and end switch signal as input and output point; Using chilled water return water temperature, upstream pressure, downstream pressure, pressure reduction, actuator aperture, input opening control signal and the flow communication point as intelligent valve MODBUS, the energy efficiency coefficient of each system is calculated according to assessment method, then in control device, analysis is optimized, change the frequency of water pump, the Based Intelligent Control such as the rotating speed of blower fan and the aperture of valve, the efficiency of system is increased substantially, thus reaches energy-saving and cost-reducing effect.

Accompanying drawing explanation

Fig. 1 is the cabinet structure schematic diagram of air-conditioning system in the present invention;

Fig. 2 is that air-conditioner set implements control structure schematic diagram;

Fig. 3 is that chilled water is for return pipe schematic diagram.

In Fig. 1: 1PLC, 2 display screens, 3 relays, 4 power supplys, 5 supply sockets, 6 transformers, 7 abs, 8 communication interfaces, 9 outputs, 10 inputs;

In Fig. 2: 11 return air temperature sensors, 12 return air humidity sensors, 13 mixing sections, 14 fillter sections, 15 surface cooling sections, 16 bringing-up sections, 17 humidifier sections, 18 blower fans, 19 air flow rate sensors, 20 humidifications control, 21 supply water temperature sensors, 22 intelligence electronic type dynamic equilibrium flow control valves, 23 alarms, 24 new air temperature sensors, 25 fresh wind tubes, 26 new air-valves, 27 backwind tubes, 28 air returning valves, 29 ajutages, 300 filters, the cold/heater of 301 table, 302 air-conditioner set blower fans;

In Fig. 3: 31 intelligent valve, 32 temperature sensors, 33 electric two-way valves, 34 fan coils.

Detailed description of the invention

With reference to accompanying drawing, the present invention is described in detail.

As shown in Figure 2,3, based on the air-conditioning system of efficiency test and appraisal with optimal control, comprise rack, PLC1(programmable logic controller (PLC) be housed in rack), display screen 2, relay 3, power supply 4, supply socket 5, transformer 6, abs 7, communication interface 8, output 9 and input 10; Wherein, power supply 4, supply socket 5, abs 7, transformer 6 connect successively, and transformer 6 is connected to each equipment of interior of equipment cabinet to realize power supply; PLC1 is connected with display screen 2 with communication interface 8 respectively.

This device also comprises air-conditioner set enforcement control structure and chilled water supplies return pipe:

Fresh wind tube 25 is equipped with new air temperature sensor 24 and new air-valve 26; Backwind tube 27 is equipped with return air temperature sensor 11, return air humidity sensor 12 and air returning valve 28; Ajutage 29 is equipped with air flow rate sensor 19; Establish filter 300 in air main, show cold/heater 301 and air-conditioner set blower fan 302; The feed pipe showing cold/heater 301 is equipped with supply water temperature sensor 21, return pipe is equipped with electronic type dynamic equilibrium flow control valve 22; Described new air temperature sensor 24, return air temperature sensor 11, return air humidity sensor 12, air flow rate sensor 19, supply water temperature sensor 21 are connected to PLC1 by the input of rack, and PLC1 is connected to motor, the electronic dynamic flow balanced valve 22, newly air-valve 26 and air returning valve 28 of air-conditioner set blower fan 302 by output.

N group fan coil is installed between chilled water feed pipe and chilled water return pipe, between fan coil and chilled water return pipe, establishes electric two-way valve 33; Intelligent valve 31 is established at chilled water return pipe end; Mounting temperature sensor 32 and pressure sensor P1, P2, P3 on chilled water feed pipe, outdoor mounted temperature sensor, each temperature sensor and pressure sensor and fan coil switching signal are connected to PLC1 through cable by the input of rack, and PLC1 is connected with described intelligent valve 31 with input 10 through output 9 in the lump by holding wire.

Described electronic type dynamic equilibrium flow control valve 22, intelligent valve 31 are the device integrating embedded software, sensing technology, intelligent controller, control valve and executing agency.The flow of chilled water can be regulated by them, the ruuning situation of unit is controlled by the scattered control system that PLC1 is embedded simultaneously, change machine class frequency accordingly according to load variations and open number of units, using unit operation efficiency as optimization target values, by optimal control, make the efficiency of unit best.The all existing matured product of electronic type dynamic equilibrium flow control valve 22, intelligent valve 31 intelligent valve, electronic type dynamic equilibrium flow control valve, the ZIPC46-EM Energy-aware type intelligent regulating valve of the ZIPC46 series that such as Hangzhou Zheda Technology Co., Ltd. produces.Because its concrete technology contents is not emphasis of the present utility model, therefore repeat no more.

In the present invention, be applied to the efficiency assessment method of air-conditioning system, comprise and the energy efficiency coefficient of handpiece Water Chilling Units, distributing system, end system and hydrodynamic system is calculated; Be specially:

(1) energy efficiency coefficient of handpiece Water Chilling Units calculates

The energy efficiency coefficient of handpiece Water Chilling Units refers to the refrigerating capacity Q of handpiece Water Chilling Units ₁and the general power N consumed ₁ratio, its computing formula is as follows:

$\mathrm{COP}\_1=\frac{Q_1}{N_1}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{{3600N}_1}$

In formula: COP_1: the energy efficiency coefficient of handpiece Water Chilling Units; Q ₁: refrigerating capacity, the refrigerating capacity that handpiece Water Chilling Units exports, kw; N ₁: the total power input of handpiece Water Chilling Units, kw; ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K;

Wherein N ₁=N ₁₁+ N ₁₂+ N ₁₃, N ₁₁for the electrical power that handpiece Water Chilling Units consumes; N ₁₂for the electrical power of chilled water pump system consumption, comprise No. 1 pump and No. 2 pumps and frequency converter; N ₁₃for the electrical power of cooling water pump system consumption, comprise cooling water pump and blower fan of cooling tower and frequency converter;

(2) energy efficiency coefficient of distributing system calculates

During system cloud gray model, by the refrigerating capacity Q measuring the chilled water pump circulation output obtained ₂with the general power N of its consumption ₂just can obtain the energy efficiency coefficient of distributing system, its computing formula is as follows:

$\mathrm{COP}\_2=\frac{Q_2}{N_2}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{{3600N}_2}$

In formula: COP_2: the energy efficiency coefficient of distributing system; Q ₂: the refrigerating capacity that chilled water pump circulation exports, kw; N ₂: the general power that chilled water pump circulation consumes, kw; ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K;

(3) energy efficiency coefficient of end system calculates

During system cloud gray model, by measuring the refrigerating capacity Q of end-equipment digestion ₃with the power N consumed ₃, just can calculate the energy efficiency coefficient of end system, its computing formula is as follows:

$\mathrm{COP}\_3=\frac{Q_3}{N_3}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{{3600N}_3}$

In formula: COP_3: the energy efficiency coefficient of end system; Q ₃: the refrigerating capacity of end system equipment digestion, kw; N ₃: the general power of end system devices consume, kw, ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K;

Wherein: N ₃=Σ N _{3_i};

N _{3_i}=N _{3i_QdP}+N _{3i_FAN}；

N _{3i_QdP}: hydrodynamic force=discharge × (end differential water pressures+valve differential water pressures);

N _{3i_FAN}: wind-power=blower fan input power;

I refers to i-th end-equipment;

(4) energy efficiency coefficient of hydrodynamic system calculates

During system cloud gray model, obtained the energy efficiency coefficient of hydrodynamic system by the volume flow of recirculated water measured and lift, its computing formula is as follows:

$\mathrm{COP}\_3W=\frac{Q_3}{{N^{\′}}_3}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{Q\·\mathrm{\ΔP}}$

In formula: COP_3W: the energy efficiency coefficient of hydrodynamic system; Q ₃: the refrigerating capacity of end system equipment digestion, kw; N' ₃: the power that pipe network consumes, kw; ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K; Q: the volume flow of recirculated water, m ³/ h; Δ P: the lift of recirculated water, m;

(5) energy efficiency coefficient of whole system calculates

The refrigerating capacity digested by end-equipment, and handpiece Water Chilling Units, end-equipment consume power, calculate the energy efficiency coefficient of whole system, its computing formula is as follows:

$\mathrm{COP}\_S=\frac{Q_3}{N_1+N_3}$

In formula: COP_S: the energy efficiency coefficient of whole system; Q ₃: the refrigerating capacity of end system equipment digestion, kw; N ₁: the total power input of handpiece Water Chilling Units, kw; N ₃: the general power of end system devices consume, kw;

(6) user is by calculating the energy efficiency coefficient obtaining whole air-conditioning system and each subsystem, obtains the evaluation result to air-conditioning system operational energy efficiency with this, makes the ruuning situation of the clearer understanding system of user's energy.

Claims (2)

1., based on the air-conditioning system of efficiency test and appraisal with optimal control, comprise the rack that PLC, input and output are housed, it is characterized in that, this system also comprises:

Fresh wind tube is equipped with new air temperature sensor and new air-valve; Backwind tube is equipped with return air temperature sensor, return air humidity sensor and air returning valve; Ajutage is equipped with air flow rate sensor; Establish filter in air main, show cold/heater and air-conditioner set blower fan; The feed pipe showing cold/heater is equipped with supply water temperature sensor, return pipe is equipped with electronic type dynamic equilibrium flow control valve; Described new air temperature sensor, return air temperature sensor, return air humidity sensor, air flow rate sensor, supply water temperature sensor are connected to PLC by the input of rack, and PLC is connected to motor, the electronic type dynamic equilibrium flow control valve, newly air-valve and air returning valve of air-conditioner set blower fan by output;

N group fan coil is installed between chilled water feed pipe and chilled water return pipe, between fan coil and chilled water return pipe, establishes electric two-way valve; Intelligent valve is established at chilled water return pipe end; Mounting temperature sensor and pressure sensor on chilled water feed pipe, outdoor mounted temperature sensor, each temperature sensor and pressure sensor and fan coil switching signal are connected to PLC through cable by the input of rack, and PLC is connected with described intelligent valve with input through output in the lump by holding wire;

Also be equipped with in described rack: relay, power supply, supply socket, transformer, abs, display screen and communication interface; Wherein, power supply, supply socket, abs, transformer connect successively, and transformer is connected to each equipment of interior of equipment cabinet to realize power supply; PLC is connected with display screen with communication interface respectively.

2. be applied to an efficiency assessment method for air-conditioning system described in claim 1, it is characterized in that, comprise and the energy efficiency coefficient of handpiece Water Chilling Units, distributing system, end system and hydrodynamic system is calculated; Be specially:

(1) energy efficiency coefficient of handpiece Water Chilling Units calculates

The energy efficiency coefficient of handpiece Water Chilling Units refers to the refrigerating capacity Q of handpiece Water Chilling Units ₁and the general power N consumed ₁ratio, its computing formula is as follows:

$COP\_1=\frac{Q_1}{N_1}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{3600N_1}$

In formula: COP_1: the energy efficiency coefficient of handpiece Water Chilling Units; Q ₁: refrigerating capacity, the refrigerating capacity that handpiece Water Chilling Units exports, kw; N ₁: the total power input of handpiece Water Chilling Units, kw; ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K;

Wherein N ₁=N ₁₁+ N ₁₂+ N ₁₃, N ₁₁for the electrical power that handpiece Water Chilling Units consumes; N ₁₂for the electrical power of chilled water pump system consumption, comprise No. 1 pump and No. 2 pumps and frequency converter; N ₁₃for the electrical power of cooling water pump system consumption, comprise cooling water pump and blower fan of cooling tower and frequency converter;

(2) energy efficiency coefficient of distributing system calculates

During system cloud gray model, by the refrigerating capacity Q measuring the chilled water pump circulation output obtained ₂with the general power N of its consumption ₂just can obtain the energy efficiency coefficient of distributing system, its computing formula is as follows:

$COP\_2=\frac{Q_2}{N_2}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{3600N_2}$

In formula: COP_2: the energy efficiency coefficient of distributing system; Q ₂: the refrigerating capacity that chilled water pump circulation exports, kw; N ₂: the general power that chilled water pump circulation consumes, kw; ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K;

(3) energy efficiency coefficient of end system calculates

During system cloud gray model, by measuring the refrigerating capacity Q that end-equipment consumes ₃with the power N consumed ₃, just can calculate the energy efficiency coefficient of end system, its computing formula is as follows:

$COP\_3=\frac{Q_3}{N_3}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{3600N_3}$

In formula: COP_3: the energy efficiency coefficient of end system; Q ₃: the refrigerating capacity of end system devices consume, kw; N ₃: the general power of end system devices consume, kw, ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K;

Wherein: N ₃=Σ N _{3_i};

N _{3_i}＝N _{3i_QdP}+N _{3i_FAN}；

N _{3i_QdP}: hydrodynamic force=discharge × (end differential water pressures+valve differential water pressures);

N _{3i_FAN}: wind-power=blower fan input power;

I refers to i-th end-equipment;

(4) energy efficiency coefficient of hydrodynamic system calculates

During system cloud gray model, obtained the energy efficiency coefficient of hydrodynamic system by the volume flow of recirculated water measured and lift, its computing formula is as follows:

$COP\_3W=\frac{Q_3}{{N^{\′}}_3}=\frac{{\mathrm{\ρC}}_P{G}_D{\mathrm{\ΔT}}_D}{Q\·\mathrm{\Δ}P}$

In formula: COP_3W: the energy efficiency coefficient of hydrodynamic system; Q ₃: the refrigerating capacity of end system devices consume, kw; N' ₃: the power that pipe network consumes, kw, ρ: chilled water density, kg/m ³; C _p: the specific heat at constant pressure of chilled water, J/ (kgK); G _d: chilled-water flow, m ³/ h; Δ T _d: chilled water supply backwater temperature difference, K; Q: the volume flow of recirculated water, m ³/ h; Δ P: the lift of recirculated water, m;

(5) energy efficiency coefficient of whole system calculates

The refrigerating capacity consumed by end-equipment, and handpiece Water Chilling Units, end-equipment consume power, calculate the energy efficiency coefficient of whole system, its computing formula is as follows:

$COP\_S=\frac{Q_3}{N_1+N_3}$

In formula: COP_S: the energy efficiency coefficient of whole system; Q ₃: the refrigerating capacity of end system devices consume, kw; N ₁: the total power input of handpiece Water Chilling Units, kw; N ₃: the general power of end system devices consume, kw;

(6) user is by calculating the energy efficiency coefficient obtaining whole air-conditioning system and each subsystem, obtains the evaluation result to air-conditioning system operational energy efficiency with this.