CN105021647B - With the soil source heat pump ground thermal response Data Processing Method of power process - Google Patents

With the soil source heat pump ground thermal response Data Processing Method of power process Download PDF

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CN105021647B
CN105021647B CN201510375309.3A CN201510375309A CN105021647B CN 105021647 B CN105021647 B CN 105021647B CN 201510375309 A CN201510375309 A CN 201510375309A CN 105021647 B CN105021647 B CN 105021647B
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moment
water
data
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CN105021647A (en
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官燕玲
江超
孟庆龙
张宇昊
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Changan University
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Abstract

The invention discloses a kind of soil source heat pump ground thermal response Data Processing Method with power process, comprising: during power-off, record power-cut time and water-in and water-out temperature; After electricity consumption recovers, test proceeds; Real-Time Monitoring water temperature recovers the moment, continues to run, meet time that water temperature recovers moment to the final test stop timing add power-cut time before the test duration equals T.T. of testing requirements; Removal power-cut time and water temperature recover the test data sheet data between the moment, and the test data sheet data after water temperature is recovered the moment are spliced in the test data sheet data before power-cut time, and the test figure obtained is as efficiency test data; Carry out the calculating of ground thermal property parameter.To wait for after the invention solves the power-off existed in prior art the soil moisture substantially recover the long and data processing of required time give up power-off before data, test duration long, the problem that can not obtain ground volumetric ratio thermal capacitance after power-off restarting.

Description

With the soil source heat pump ground thermal response Data Processing Method of power process
Technical field
The invention belongs to technical field of ground source heat pump, relate to a kind of soil source heat pump ground thermal response Data Processing Method with power process.
Background technology
Soil source heat pump ground heat exchanger makes the ground outside the water of pipe Inner eycle and pipe carry out heat interchange by vertical buried pipe.Because the temperature of ground is cool in summer and warm in winter relative to earth's surface air, therefore source pump performance is higher than the air source heat pump of routine, becomes the renewable energy technologies actively promoted.
Ground thermal property parameter is the basic data of Design Ground-source Heat Pump systematically buried tube heat exchanger, and inaccurate thermal physical property parameter can the economy of influential system design and reliability.So the research of the ground thermal property theory of testing and method is an emphasis of soil source heat pump technical field research.The concept of thermal response test is proposed in nineteen eighty-three by Mogensen the earliest, its based on infinite line thermal source theory at constant thermal discharge or under getting heat condition, fluid is allowed to circulate in ground heat exchanger, the out temperature of monitoring pipe inner fluid and flow, inverse goes out the coefficient of heat conductivity of soil.The middle and later periods nineties, Swede EklofC. and GehlinS. develops on-the-spot thermal response testing equipment based on this concept.Subsequently, thermal response experimental technique is widely used in multiple country such as Canadian, Chilean, German.The design specifications that China promulgates for 2009, requires before engineering design, carry out ground thermal response test, in this, as the basic foundation of design." specification " requires that thermal response is tested with constant thermal discharge, detect the Inlet and outlet water temperature of pipe laying, continuous operation more than two days, (refer within the time being no less than 12h when pipe laying Inlet and outlet water temperature reaches steady state (SS), the fluctuation of its temperature is less than 1 DEG C) test can be stopped, apply infinite line heat source model principle again and analytical calculation is carried out to test figure, finally obtain the complex heat transfer coefficient of ground and the trial value of volumetric ratio thermal capacitance.
Due to ground thermal response process of the test require continuous print stable add heat, the conditional request of infinite line heat source model could be met like this.Oklahoma, United States stands university and international earth source heat pump consortium specification ground thermal response test, and regulation is when the failure of test midway, the temperature return of ground should be waited can to start again to test to close to initial temperature, namely test will be restarted, require that circulating fluid temperature (i.e. the soil moisture) should within 0.3K with the deviation of soil initial temperature, namely Soil Temperature Field reaches basic recovery [1].Experiments and numerical studies shows, when the comprehensive coefficient of heat conductivity of ground is 2.013W/ (mK), be 5000W at heating power, single U-shaped pipe laying, under the condition of boring buried depth 100m, run the 10.8th day after stopping heating in two days, the temperature of recirculated water just can return to and differ 0.25K with initial temperature (soil initial temperature).
Due to power failure and abort often can be met with an accidet in test, at this moment the ground of pipe laying periphery heat by the test of leading portion, as mentioned above, wanting substantially to return to initial temperature needs for a long time, will certainly affect normally carrying out of test.If run into problems, can not consider the recovery in temperature field, test is then carried out, and how such test figure processes, and this is the problem that engineering first-line staff is concerned about very much.
In prior art one (document [1]), after running into power-off in thermal response test, must wait until that the deviation of circulating fluid temperature and soil initial temperature is less than 0.3K and just can restarts, namely Soil Temperature Field will reach basic recovery, then testing bore holes is re-started geo-thermal response test as the new boring not doing overtesting above.Returned to the deviation of soil initial temperature within 0.3K by the soil moisture (temperature representative with the recirculated water in pipe laying) being de-energized front heating, required time is longer.This release time affects by the heating power before power-off and heat time, and after heating in two days, release time can reach more than 10 days.Wait the soil moisture substantially to recover just can re-start test, this restriction will have a strong impact on the time needed for whole test process.
Prior art two (document [2] [3]) application imbedded pipe heat-exchanging ultimate principle, proposes a kind of analytic method, and the method does not need to wait the soil moisture substantially to recover then to test after a loss of power.Document [2] proposes release time (RecoveryTime) method, its method is according to interrupting the moment, interrupting perdurability etc., determine the release time of corresponding a certain error, corresponding error is less, release time is longer, the test period of having no progeny in making reaches the requirement of release time, obtains the coefficient of heat conductivity of ground thus.Document [3] improves document [2], proposes the method for equivalent time (EquivalentTime), applies the data after restarting, obtains the coefficient of heat conductivity of ground.
Citing document:
[1]Closed-Loop/GeothermalHeatPumpSystems:DesignandInstallationStandards2010Edition
[2]RichardA.Beier,MarvinD.Smith.AnalyzingInterruptedIn-SituTestsonVerticalBoreholes.ASHRAETransactions,2005.111(1).702-713.
[3]RichardA.Beier.EquivalentTimeforInterruptedTestsonBoreholeHeatExchangers.HVAC&RRESEARCH.2008.14(3).489-505.
The defect existed in document [2], [3]:
(1) data processing only retains the test figure after power-off, and the test figure before power-off is given up to fall, and have ignored the impact of test data before power-off like this.
(2) ground coefficient of heat conductivity k can only finally be obtained s(W/ (m DEG C)), can not obtain ground volumetric ratio thermal capacitance ρ sc s(J/ (m 3dEG C)) trial value.
Summary of the invention
Technical matters to be solved by this invention is: to wait for after the power-off existed in prior art one soil moisture substantially recover data before data processing gives up power-off in the long and prior art two of required time, power-off restarting after the test duration long, ground volumetric ratio thermal capacitance can not be obtained.
The present invention is directed to above-mentioned technical matters, a kind of soil source heat pump ground thermal response Data Processing Method with power process is provided.
To achieve these goals, the present invention adopts following technical scheme to be solved:
With a soil source heat pump ground thermal response Data Processing Method for power process, comprising:
The first step, test ground initial temperature T 0;
Second step, rinses U-shaped vertical buried tube;
3rd step, testing tool is connected with the U-shaped vertical buried tube of instrument connection, and carries out necessary insulation;
4th step, circulating water flow in the setting heating power of well heater and pipe, and keep in test constant;
5th step, starts running, tests, continuously water circulation flow and heating power in record U-shaped vertical buried tube inflow temperature, leaving water temperature, pipe;
6th step, during power-off, water circulating pump and well heater stopped work, the water-in and water-out temperature of record power-cut time and this moment U-shaped vertical buried tube;
7th step, after electricity consumption recovers, start water pump and well heater immediately, test proceeds;
8th step, Real-Time Monitoring water temperature recovers the moment, continues afterwards to run, meet time that water temperature recovers moment to the test stop timing add power-cut time before the test duration equals T.T. of testing requirements;
9th step, remove the test data sheet data between power-cut time to water temperature recovery moment, the test data sheet data after water temperature is recovered the moment are spliced in the test data sheet data before power-cut time, and the test figure obtained is as efficiency test data;
Tenth step, the efficiency test data the 9th step obtained carry out the calculating of ground thermal property parameter as the test data that thermal response is tested.
Further, in described 5th step, writing time, step-length was not more than 10 minutes.
Further, the T.T. of the described testing requirements of described 8th step is for being not less than 48h.
Accompanying drawing explanation
Fig. 1 is the recording curve of the circulating water temperature of the test having power process.
Fig. 2 is the data processing curve in prior art two.
Fig. 3 illustrates with the splicing of the test data of power process in method of the present invention.
Embodiment
Embodiment:
Soil source heat pump ground thermal response Data Processing Method with power process of the present invention comprises the following steps:
The first step, test ground initial temperature T 0;
Second step, rinses U-shaped vertical buried tube;
3rd step, testing tool is connected with the U-shaped vertical buried tube of instrument connection, and carries out necessary insulation;
4th step, circulating water flow in the setting heating power of well heater and pipe, and keep in test constant;
5th step, starts running, tests, continuously water circulation flow and heating power in record U-shaped vertical buried tube inflow temperature, leaving water temperature, pipe, and writing time, step-length was set to 1 minute;
6th step, during power-off, water circulating pump and well heater stopped work, the water-in and water-out temperature of record power-cut time and this moment U-shaped vertical buried tube;
7th step, after electricity consumption recovers, start water pump and well heater immediately, test proceeds;
8th step, Real-Time Monitoring water temperature recovers the moment (namely the water temperature in this moment is identical with power-cut time water temperature), continue afterwards to run, meet time that water temperature recovers moment to the test stop timing add power-cut time before the test duration equals T.T. of testing requirements; Therefore, actual tests T.T. is add have a power failure perdurability and water temperature release time the T.T. of testing requirements, and the T.T. of testing requirements is not less than 48h, gets 48h in the present embodiment; In this process, record water circulation flow and heating power in the Inlet and outlet water temperature of U-shaped vertical buried tube, pipe continuously.
9th step, remove the test data sheet data between power-cut time to water temperature recovery moment, the test data sheet data after water temperature is recovered the moment are spliced in the test data sheet data before power-cut time, and the test figure obtained is as efficiency test data;
Tenth step, the efficiency test data the 9th step obtained carry out the calculating of ground thermal property parameter as the test data that thermal response is tested, in the present embodiment, this step adopts the method in prior art one to carry out.
Below key problem in technology of the present invention point is introduced in detail:
As shown in Figure 3, solid line is Continuous Heat response test test water temperature curve, and dotted line is τ 1moment power failure is rear, τ 2moment restart after thermal response test water temperature curve.For the geo-thermal response test curve having power-off, find on this curve with τ 1the point τ that moment (power-cut time) temperature is identical a, then continue test to τ 4moment, by (τ a, τ 4) test curve and (0, the τ of time period 1) time period curve matching together, new geo-thermal response test curve can be obtained, in fact with recording (τ a, τ 4) data in the time period replace without (the τ on power process test curve 1, τ 3) solid line of time period.Continuous Heat response test curve is replaced to carry out the calculating of ground thermal property parameter with spliced geo-thermal response test curve.(τ 2, τ a) be Δ τ=τ release time of the soil moisture during this period of time a-τ 2.
By having a power failure, the data after restarting are spliced by the point that temperature is equal with the data before power failure, obtain the approximate trial curve of corresponding constant continuous duty q.
For constant continuous duty q (q is the heat flux of unit length pipe laying release, W/m), τ moment recirculated water medial temperature can be calculated by the formula (1) in prior art one:
T f ( τ ) - T 0 = q · [ R b + 1 4 πk s · E i ( d b 2 ρ s c s 16 k s τ ) ] - - - ( 1 )
In formula, T ffor the arithmetic mean of the Inlet and outlet water temperature of U-shaped vertical buried tube, DEG C; Q is the heat flux of unit length pipe laying release, W/m; d bfor bore diameter, m; k sfor the coefficient of heat conductivity of ground, W/m DEG C; ρ sc svolumetric ratio thermal capacitance, J/ (m 3dEG C); R bfor boring internal thermal resistance, m DEG C/W, calculate by the computing formula (2) in prior art one:
R b = 1 2 { 1 2 πk b [ ln ( d b d o ) + ln ( d b D ) + k b - k s k b + k s · ln ( d b 4 d b 4 - D 4 ) ] + 1 2 πk p · ln ( d o d i ) + 1 πd i h } - - - ( 2 )
In formula, D is the centre distance of two pipe layings, m; d ifor pipe laying internal diameter, m; d ofor pipe laying external diameter, m; k pfor pipe laying tube wall heat conduction coefficient, W/ (m DEG C); k bfor interior backfilling material coefficient of heat conductivity of holing, W/ (m DEG C).H is the surface coefficient of heat transfer between recirculated water and tube wall, W/ (m 2dEG C); Other is the same.
Ground coefficient of heat conductivity k in formula (1) s, volumetric ratio thermal capacitance ρ sc swith the coefficient of heat conductivity k of backfilling material ball as unknown quantity, three parameter estimation (equation left side parameter is known) can be carried out according to trial curve (data), can k be obtained s, ρ sc sand k bvalue.
Beneficial effect of the present invention is analyzed as follows:
1, the test figure before and after power-off is valid data, and for Data processing, data volume is more, more comprehensively.
As shown in Figure 1, the ordinate of Fig. 1 is U-shaped pipe laying water-in and water-out temperature averages T fwith ground initial temperature T 0difference, horizontal ordinate is the test run time.
Fig. 1 is the thermal response test data sheet curve with power process, as can be seen from this curve, the present invention is different from prior art two, first prior art two gives up A section test data, and then draw " temperature-logarithmic time " curve (as Fig. 2) according to B section, select last equivalent time Δ τ on this curve esegment of curve carry out linear fit; And B segment data is spliced to A section by the present invention carries out data analysis, the data volume selected is than prior art more than two, and data also more comprehensively.
Δ τ in Fig. 2 etest duration (equivalent time) for through conversion:
Δτ e = τ 2 - τ 1 τ 2 × τ - τ 2 τ - τ 1 × τ - - - ( 3 )
In formula, τ 1for having a power failure the moment; τ 2for reset time; τ is the test run time, τ > τ in Fig. 2 2.
2, do not need to wait the soil moisture to recover, save the test duration.
Compared to the soil moisture restoration methods of prior art one, the present invention has obviously saved portion of time.This be due to prior art one require power-off after restart test, the deviation of circulating fluid temperature and soil initial temperature will within 0.3K, therefore will place the long period just can re-start test.
3, method of the present invention can obtain ground coefficient of heat conductivity k simultaneously s, ground volumetric ratio thermal capacitance ρ sc swith the coefficient of heat conductivity k of backfilling material b.
The present invention, under time-saving condition, can obtain the result same with prior art one, namely can obtain the comprehensive coefficient of heat conductivity k of ground by experimental data processing s(W/ (m DEG C), ground volumetric ratio thermal capacitance ρ sc s(J/ (m 3dEG C)) and the coefficient of heat conductivity k of backfilling material b(the trial value of W/ (m DEG C).
When prior art two carries out data processing by formula (4), with ln Δ τ efor horizontal ordinate, [T f(τ)-T f(τ 2)] be ordinate drafting test curve (Fig. 2), select last equivalent time Δ τ on this curve esegment of curve carry out linear fit, obtain slope and the intercept of fit line.K can be calculated by formula (4) according to slope svalue, but can not ρ be obtained sc svalue and k bvalue.
T f ( τ ) - T f ( τ 2 ) = q 4 πk s [ lnΔτ e + l n ( 4 a s γr b 2 ) + 4 πk s R b ] - - - ( 4 )
In order to validity of the present invention is described, below carry out the contrast of distinct methods result:
The result of the data analysis by the technology of the present invention and prior art 2,5 being had to power-off operating mode is summarized in table 1.These 5 kinds of operating modes are and run to 9h and run into power failure, the interval time restarted again is different, is respectively 10 minutes (operating mode 1), 30 minutes (operating mode 2), 1 hour (operating mode 3), 5 hours (operating modes 4) and 10 hours (operating mode 5).Example condition is: heat flux q=50W/m, the ground coefficient of heat conductivity k of the release of unit length pipe laying s=2.0W/ (m DEG C), ground volumetric ratio thermal capacitance ρ sc s=3.0 × 10 6j/ (m 3. ), backfilling material coefficient of heat conductivity is k b=1.5W/ (m DEG C), bore diameter 160mm, U-tube external diameter Φ 32mm, thickness of pipe are 3mm, U-tube centre distance 80mm, tubing coefficient of heat conductivity are 0.42W/ (m DEG C), circulating water flow is 1.0m 3/ h.Corresponding boring internal thermal resistance R b=0.164m DEG C/W.Relative error in table is the relative actual value of analysis result, and actual value is the respective value in example condition.
The Comparative result of table 1 prior art two and the technology of the present invention
The ground coefficient of heat conductivity k that this inventive method process obtains can be seen from the result contrast of table 1 s, ground volumetric ratio thermal capacitance ρ sc s, backfilling material coefficient of heat conductivity k ball very close to actual value.Corresponding each operating mode, the ground coefficient of heat conductivity k that the method for this invention obtains svalue than prior art two closer to actual value.Prior art two can not obtain ground volumetric ratio thermal capacitance ρ sc swith backfilling material coefficient of heat conductivity k b.

Claims (3)

1., with a soil source heat pump ground thermal response Data Processing Method for power process, comprising:
The first step, test ground initial temperature T 0;
Second step, rinses U-shaped vertical buried tube;
3rd step, testing tool is connected with the U-shaped vertical buried tube of instrument connection, and carries out necessary insulation;
4th step, circulating water flow in the setting heating power of well heater and pipe, and keep in test constant;
5th step, starts running, tests, continuously water circulation flow and heating power in record U-shaped vertical buried tube inflow temperature, leaving water temperature, pipe;
It is characterized in that, further comprising the steps of:
6th step, during power-off, water circulating pump and well heater stopped work, the water-in and water-out temperature of record power-cut time and this moment U-shaped vertical buried tube;
7th step, after electricity consumption recovers, start water pump and well heater immediately, test proceeds;
8th step, Real-Time Monitoring water temperature recovers the moment, continues afterwards to run, meet time that water temperature recovers moment to the test stop timing add power-cut time before the test duration equals T.T. of testing requirements;
9th step, remove the test data sheet data between power-cut time to water temperature recovery moment, the test data sheet data after water temperature is recovered the moment are spliced in the test data sheet data before power-cut time, and the test figure obtained is as efficiency test data;
Tenth step, the efficiency test data the 9th step obtained carry out the calculating of ground thermal property parameter as the test data that thermal response is tested.
2., as claimed in claim 1 with the soil source heat pump ground thermal response Data Processing Method of power process, it is characterized in that, in described 5th step, writing time, step-length was not more than 10 minutes.
3., as claimed in claim 1 with the soil source heat pump ground thermal response Data Processing Method of power process, it is characterized in that, the T.T. of the described testing requirements of described 8th step is for being not less than 48h.
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CN110376241B (en) * 2019-07-16 2022-03-11 中国计量大学 Method for measuring heat transfer factor and system heat capacity of oscillating type calorimetric reaction kettle
CN116401883B (en) * 2023-04-14 2023-09-26 中南大学 Parameter inversion method and system for interrupt thermal response test of buried pipe heat exchanger

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