CN101986221B - Method for controlling constant heat flow in ground source heat exchanger heat transfer performance test - Google Patents

Abstract

The invention discloses a method for controlling constant heat flow in a ground source heat exchanger heat transfer performance test, which is characterized in that: a heat pump unit for generating cold water in the test is a fixed frequency compressor, and a silicon controlled controller is used for controlling electric heating power; the refrigerating power of a heat pump is calculated according to the temperatures and flow rates of water at the inlet and outlet of the heat pump and is compared with the set heat exchange quantity of a ground source heat pump soil heat exchanger; and when the refrigerating power of the heat pump is unequal to the set value, the output current of the silicon controlled controller and the heating quantity of an electric heater are changed, so that cold water heat flow entering the soil heat exchanger is constant. The temperatures of the water at the inlet and outlet of the heat exchanger are acquired by a temperature sensor; electric heating output power is adjusted according to an algorithm; control accuracy and response speed are high; corresponding control programs can be combined with the ground source heat pump heat exchanger heat transfer performance test program to be operated simultaneously; and the requirement of the constant heat flow in the ground source heat pump heat exchanger heat transfer performance test is fully met.

Description

The control method of constant heat flux in the source heat exchanger heat-obtaining performance test of a kind of ground

Technical field

The present invention relates to the control method of constant heat flux in the performance test of a kind of earth source heat pump heat interchanger heat-obtaining.

Background technology

Utilization is that buildings carries out heating and refrigerating with ground surface soil or water source as the earth source heat pump of cold/heat source, has become in recent years the hot technology of building energy conservation both at home and abroad.And the heat transfer property and the operational reliability of ground source heat exchanger are the keys of this type power-saving technology success or not.Because aspect parameters such as the geology formation on the face of land, water regime, physical characteristics have nothing in common with each other, corresponding heat transfer property will change thereupon, and the heat transfer property of the ground source heat exchanger of therefore burying underground in different regions will be different.Be engaged in ground source heat exchanger design; Especially concerning heavy construction; It is not enough, insecure only carrying out theoretical research or laboratory heat transfer experimental study; Therefore developed country such as U.S. clear and definite regulation in technical standard is studied the precondition as engineering feasibility study and engineering design to the site test of carrying out the ground source heat exchanger at the construction field (site).

According to relevant regulations among State Standard of the People's Republic of China's " earth-source hot-pump system engineering legislation " GB50366-2005; In doing the performance test of earth source heat pump heat interchanger heat-obtaining, require refrigeration work consumption should keep constant; As can not keep the constant of hot-fluid, can have influence on the precision of test result of ground source heat pump heat exchanger heat-transfer performance test.In the performance test of earth source heat pump heat interchanger heat-obtaining, the source pump of employing invariable frequency compressor is produced cold water and is offered the soil heat exchange device, with the exchange capability of heat of testing soil heat interchanger.The performance test of earth source heat pump heat interchanger heat-obtaining; Be to utilize anti-inference method to derive the ground thermal property parameter; Its method is: from computing machine, take out the experimental test result; The result of itself and software simulation is compared; Make that variance when obtaining minimum value, promptly is ask result through the adjusted thermal physical property parameter of heat transfer model with

.Wherein, T _{Cal, i}It is the medial temperature of the pipe laying inner fluid that constantly goes out by Model Calculation of i; T _{Exp, i}It is the medial temperature of fluid in the pipe laying of i actual measurement constantly; N is the group number of the data of experimental measurement.Deciding under the condition of heating power: τ is the recirculated water medial temperature constantly, for

$T_f=T_{\mathrm{ff}}+q_l\·[R_b+\frac{1}{{4\mathrm{\π\λ}}_s}\·\mathrm{Ei}\left(\frac{d_b^2{\mathrm{\ρ}}_s{c}_s}{16{\mathrm{\λ}}_s\mathrm{\τ}}\right)]$

Following formula has constituted in the complete pipe laying recirculated water and the heat exchange equation of ground on every side.Two unknown parameters are arranged, on every side ground coefficient of heat conductivity λ in the formula _sWith volumetric ratio thermal capacitance ρ _sc _s, utilize this formula can be in the hope of above-mentioned two unknown parameters.From formula, can find out in order to accomplish test request smoothly, must guarantee through the hydro-thermal stream of underground heat interchanger constant.In actual use; When source pump environment temperature of living in is that condensing temperature changes; Can make the source pump refrigerating capacity change, the hot-fluid that causes supplying with ground heat exchanger cold water changes, and can not satisfy the condition of desired constant heat flux in the performance test of earth source heat pump heat interchanger heat-obtaining.Adopted frequency-changeable compressor in the partial test device, can change refrigerating capacity through changing the compressor compresses amount, but the method cost has been high, control is complicated, and precision does not receive artificial control, and changing factor is many, can not reach the purpose of permanent hot-fluid fully.

Summary of the invention

Goal of the invention: the objective of the invention is to deficiency to prior art; The control method of constant heat flux in the source heat exchanger heat-obtaining performance test of a kind of ground is provided; Through being regulated, electric heater capacity realizes that constant heat flux control is carried out in the experiment of source heat exchanger heat-obtaining over the ground; Improved the precision and the controlling performance of control greatly, can be engineering design reliable foundation is provided.

Technical scheme: the control method of constant heat flux in the ground of the present invention source heat exchanger heat-obtaining performance test, the source pump of producing cold water in the test adopts invariable frequency compressor, uses controllable silicon controller control electrical heating power; Calculate the refrigeration work consumption of heat pump according to heat pump turnover saliva water temperature and flowmeter; Compare with the earth source heat pump soil heat exchange device heat of setting; When the refrigeration work consumption of heat pump and setting value are unequal; Change the controllable silicon controller output current, change electric heater and add heat, make that the cold water hot-fluid that gets into the soil heat exchange device is constant.

Specifically comprise the steps:

(1) basis is positioned at the temperature sensor of source pump evaporator import and export, temperature value and the flow value that flow sensor collects calculates the refrigeration work consumption of heat pump at this moment;

(2) in time step, judged result be " being ", entering step (3) the inspection regulation and control time difference; Judged result is a "No", then continues scanning;

(3) heat of heat interchanger in this test that estimates according to earth source heat pump heat interchanger actual conditions, the source pump refrigeration work consumption that calculates with step (1) compares, if relative error between the two surpasses the numerical value of setting, just changes the heat of well heater; When refrigeration work consumption is less than normal, reduce the certain value of output current of controllable silicon controller; When refrigeration work consumption is bigger than normal, increase the certain value of output current of controllable silicon controller.

(4) behind the change heater heats power, returned for (1) step, continue monitoring source pump refrigeration work consumption; After surpassing the regular hour step-length, reach the heating effect of electric heater, this moment is if the error of refrigeration work consumption and heat interchanger heat still surpasses the limits of error; Then continue to regulate; If after regulating a period of time, satisfy error requirements, keep electrical heating power, continue test.

Through above control method, can keep the condition of constant heat flux basically in the performance test of earth source heat pump heat interchanger heat-obtaining, thereby reach the purpose of the thermophysical property of measured soil.

The present invention compared with prior art, its beneficial effect is: 1, the inventive method adopts electric heater and controllable silicon to combine heat pump to regulate cooling and warming power, and is safe and reliable to operation; Easy to adjust; With low cost, the control robotization, what particularly be directed against the proving installation employing is invariable frequency compressor; The problem that the cooling and warming power of source pump can not in time change takes the inventive method can reach the requirement of relevant criterion fully; 2, the present invention imports and exports water temperature through the temperature sensor heat collecting exchanger; Regulate the electrical heating output power according to algorithm; Control accuracy is high; Response speed is fast, and corresponding control programs can be incorporated into operation simultaneously in the ground source heat pump heat exchanger heat-transfer performance test procedure, fully satisfies the requirement of constant heat flux in the ground source heat pump heat exchanger heat-transfer performance test; 3, the present invention changes the heater heats electric current through increasing controllable silicon controller control, thereby changes the heater heats amount, to offset the change amount of source pump refrigeration work consumption, reaches the control purpose of constant heat flux; 4, the present invention is directed to the source pump that adopts invariable frequency compressor in the performance test of earth source heat pump heat interchanger heat-obtaining and carry out permanent hot-fluid control; Perfect in shape and function is arranged; Precise control; Characteristics such as simple in structure can obtain accurate more test data so that the performance test of earth source heat pump heat interchanger heat-obtaining can better remain on good test mode.

Description of drawings

Fig. 1 is the permanent hot-fluid control flow chart of earth source heat pump heat interchanger heat-obtaining performance test of the present invention;

Fig. 2 is the soil heat exchange device heat curve of the concrete test case of the present invention.

Embodiment

Below in conjunction with accompanying drawing, through a most preferred embodiment, technical scheme of the present invention is elaborated, but protection scope of the present invention is not limited to said embodiment.

The present invention changes the heater heats electric current through behind fixed unit frequently, increasing controllable silicon controller control, thereby changes the heater heats amount, to offset the change amount of source pump refrigeration work consumption, reaches the control purpose of constant heat flux.Though this method is with low cost, and is simple in structure, range of control is big; Precision is high, and response is fast, and degree of freedom is big; Satisfy the requirement of earth source heat pump heat interchanger heat-obtaining performance test fully, make the good test mode of remaining on of proving installation, obtain accurate more test data.

The concrete constant control method of maintenance hot-fluid may further comprise the steps:

The first step: the temperature value and the flow value that collect according to the temperature sensor that is positioned at source pump evaporator import and export, flow sensor calculate the refrigeration work consumption of heat pump at this moment;

Second step: the inspection regulation and control time difference, in time step, judged result be " being ", the entering step 3; Judged result is a "No", then continues scanning;

The 3rd step: the heat of heat interchanger in this test that estimates according to earth source heat pump heat interchanger actual conditions; The source pump refrigeration work consumption that calculates with the first step compares; If between the two relative error surpasses certain numerical value (for example 5%), just need to change the heat of well heater; When refrigeration work consumption is less than normal, reduce the certain value of the output current of controllable silicon controller (probably being 0.5mA), when should refrigeration work consumption bigger than normal, increase the certain value (probably being 0.5mA) of output current of controllable silicon controller.

The 4th step: after changing heater heats power, return the first step, continue monitoring source pump refrigerating capacity; After surpassing the regular hour step-length, reach the heating effect of electric heater, this moment is if the error of refrigeration work consumption and heat interchanger heat still surpasses the limits of error; Then continue to regulate; If after regulating a period of time, satisfy error requirements, keep electrical heating power, continue test.

Through above control strategy, can keep the condition of constant heat flux basically in the performance test of earth source heat pump heat interchanger heat-obtaining, thereby reach the purpose of the thermophysical property of measured soil.

Fig. 2 has provided and has used earth source heat pump heat interchanger heat-obtaining performance test case history of the present invention, is illustrated in the control effect that adopts earth source heat pump heat interchanger heat-obtaining performance test proving installation behind the present invention to can be good at accomplishing constant heat flux.

As stated, although represented and explained the present invention that with reference to specific preferred embodiment it shall not be construed as the restriction to the present invention self.Under the spirit and scope of the present invention prerequisite that does not break away from the accompanying claims definition, can make various variations in form with on the details to it.

Claims (1)

1. the control method of constant heat flux in the ground source heat exchanger heat-obtaining performance test, it is characterized in that: the source pump of producing cold water in the test adopts invariable frequency compressor, uses controllable silicon controller control electrical heating power; Calculate the refrigeration work consumption of heat pump according to heat pump turnover saliva water temperature and flowmeter; Compare with the earth source heat pump soil heat exchange device heat of setting; When the refrigeration work consumption of heat pump and setting value are unequal; Change the controllable silicon controller output current, change electric heater and add heat, make that the cold water hot-fluid that gets into the soil heat exchange device is constant;

Specifically comprise the steps:

(1) basis is positioned at the temperature sensor of source pump evaporator import and export, temperature value and the flow value that flow sensor collects calculates the refrigeration work consumption of heat pump at this moment;

(2) in time step, judged result be " being ", entering step (3) the inspection regulation and control time difference; Judged result is a "No", then continues scanning;

(3) heat of heat interchanger in this test that estimates according to earth source heat pump heat interchanger actual conditions, the source pump refrigeration work consumption that calculates with step (1) compares, if the over proof numerical value of relative error between the two, just changes the heat of well heater; When refrigeration work consumption is less than normal, reduce the certain value of output current of controllable silicon controller; When refrigeration work consumption is bigger than normal, increase the certain value of output current of controllable silicon controller;

(4) behind the change heater heats power, returned for (1) step, continue monitoring source pump refrigeration work consumption; After surpassing the regular hour step-length, reach the heating effect of electric heater, this moment is if the error of refrigeration work consumption and heat interchanger heat still surpasses the limits of error; Then continue to regulate; If after regulating a period of time, satisfy error requirements, keep electrical heating power, continue test.

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