CN100501366C - Apparatus and method for quick measurement of heat performance of solar heat collector - Google Patents

Abstract

The present invention relates to a device and a method for quickly measuring the heat performance of a solar heat collector. The bottom part of a water tank of a testing table of the device is connectDisclosed are a device and a method for measuring the heat characters of solar collector. The measuring device comprises: a testing platform which has a drain pipe and a water pump connected with the ed with a drain pipe and a water pump. An overflow pipe and a heat exchanger are installed on the lateral surface of the water tank. The left side of the water tank is connected with a circulating watbottom of the water tank, on the sides of the water tank is provided with an overflow pipe and a heat exchanger; the left side of the water tank is connected with cycle water pump and a parallel by-paer pump and a parallel by-pass valve through a gate valve; then, the left side of the water tank is connected to a filter, a flowmeter, a needle valve and a heat collector. An outlet of the heat colless valve via a gate valve, and then connected to a filter, flow counter and a needle valve, and then connected with the heat collector; the output of the heat collector is connected with an air releasctor is connected with one exhaust valve and two gate valves, wherein one gate valve is connected to the water tank. A blower fan, an anemometer and a white shelter are arranged near the heat collectoe valve and two gate valves, and one way is connected with the water tank. A draught fan, a wind-velocity indicator and a white shelter are placed near to the heat collector. A general solarimeter andr. A main pyranometer and a solar corona ring are installed on the surface of the heat collector. The flow can be controlled and kept constant by using the present invention. The relative flow, the to a solar corona are installed on the surface of the heat collector. The angle between the direct solar radiation and the normal line of the heat collector is less than 5DEG. tal radiation intensity, the temperatures of an inlet and an outlet of the heat collector, the environmental temperature and the wind speed are collected by a data collecting instrument. The heat collector is adjusted by the solar corona ring so that the included angle of the direct solar radiation and the normal of the heat collector is less than 5 DEG. The measuring method mainly considers that glass of a vacuum heat collecting tube, metal and water in the heat collector have a big heat lag.

Description

Heat performance of solar heat collector rapid measurement device and measuring method

Technical field

The present invention relates to a kind of solar heat collector thermal behavior rapid measurement device and measuring method, belong to solar energy heat utilization field.

Background technology

The testing standard of existing solar thermal collector is based on steady-state method of test, measures stable state or metastable state momentary efficiency and heat collector heat loss coefficient that content comprises heat collector.Steady-state method of test is very high to the requirement of meteorologic parameter.For example: (it is fine in test period that GB/T 4271-2000 requires, and solar irradiance is at 800W/m2 for the enough high and stable radiation and the environment temperature of strict and steady etc.More than, in experimental period the deviation value of solar irradiance be no more than mean value ± 50W, the variation of heat collector ambient temperature can not surpass mean value ± 1K at test period.In the operating temperature range of heat collector, get four uniform fluid inlet temperatures in interval at least.One of them should ambient air temperature ± 3 ℃ in).Because outdoor test meteorological condition can't artificially be controlled, it is fixed that the time of test need come according to the meteorological condition of locality, in the area that has, because the restriction of weather conditions can't be carried out in some test in season at all.Thereby, adopt this method to test, the cycle can be very long sometimes.

In practice, heat collector mostly is to be operated in the dynamic atmospheric environment, is not inconsistent with the test condition of prescribed by standard, is used in the thermal output meeting that the result who obtains under the steady state conditions predicts dynamic operation condition and produces certain error.For thermal behavior that can faster more accurate prediction heat collector with instruct the design of heat collector, need the device for quick testing and the method for testing of a kind of heat performance of solar heat collector of research badly.

Summary of the invention

The objective of the invention is to provide a kind of heat performance of solar heat collector rapid measurement device, utilize solar thermal collector that outwork to input variable: relevant parameter is determined in the response of solar irradiation intensity, environment temperature, heat collector temperature in transient change, utilizes the parameter that has obtained to combine with corresponding mathematical model and algorithm to realize the prediction that heat collector is exported afterwards.Another purpose of the present invention provides the quick measuring method of a kind of heat collector thermal behavior, it has considered the thermal capacitance of heat collector itself and the caused heat lag phenomenon of thermal capacitance of the interior water of heat collector, use transfer function method that the input and output of heat collector are coupled together, make method more feasible, more effective.

Heat performance of solar heat collector rapid measurement device and measuring method are:

One baffle plate 30 is arranged in the water tank 1 of its test board, the top connects the filling pipe and first gate valve 3, run-down pipe 4 and heat exchanger 5 are equipped with in the side, tapping pipe and the pipeline that has second gate valve 6 is equipped with in water tank 1 bottom, be connected with the 3rd gate valve 7 and water pump 8 on the described pipeline in turn, the 4th gate valve 9, water tank 1 left side connects the 5th gate valve 10 successively, water circulating pump 11, filtrator 13, flowmeter 2, needle-valve 14 and viewport 15, described water circulating pump 11 is connected with by-pass valve 12 side by side, described viewport 15 is connected in the import 17 of heat collector 16, its outlet 18 connects an air release 19, described air release 19 links to each other with the 7th gate valve 21 with the 6th gate valve 20 respectively, described the 7th gate valve 21 links to each other with water tank 1, in import 17 and outlet 18 places first temperature probe 27 and second temperature probe 28 are installed, in the centre position of heat collector plane one side one pyramometer 24 is installed, one corona 26 is installed in same plane, installation one blower fan 22 and anemoscope 25 near test board, in distance test board 15m, be not less than apart from the ground height white thermometer screen 23 is installed in the scope of 1m, the thermometer 29 of interior dress measures ambient temperature, the import 17 and the outlet 18 of heat collector all will be done insulation.

Open data collecting instrument; The water pump 8 that starts water tank 1 makes stability of flow to guarantee the pressure of water circulating pump 11 suction inlets, starts water circulating pump 11, adjusts the aperture of by-pass valve 12 and needle-valve 13, so that flow is to setting value.

The theoretical model of measuring method is pressed:

${\mathrm{\θ}}_0\left(n\right)=\underset{m=0}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\θ}}_i(n-m)h_1\left(m\right)+\underset{m=0}{\overset{N}{\mathrm{\Σ}}}\hat{G}(n-m)h_2\left(m\right)+\underset{m=0}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\θ}}_a(n-m)h_3\left(m\right)$

Wherein: $\hat{G}=G-\stackrel{\‾}{G},$ ${\widehat{\mathrm{\θ}}}_b=T_b-{\stackrel{\‾}{T}}_b,$ ${\widehat{\mathrm{\θ}}}_a=T_a-{\stackrel{\‾}{T}}_a,$ ${\widehat{\mathrm{\θ}}}_i=T_i-{\stackrel{\‾}{T}}_i,$ ${\widehat{\mathrm{\θ}}}_o=T_o-{\stackrel{\‾}{T}}_o$

G: solar irradiance, W/m ²

T _b: the temperature of solar energy evacuated inner glass tube wall, ℃;

T _i: heat collector fluid intake temperature, ℃;

T _a: environment temperature, ℃;

T _o: the heat collector fluid outlet temperature, ℃;

G, T _b, T _i, T _a, T _o: G under the equilibrium state, T _b, T _i, T _a, T _oValue;

N, m-n, m: refer to variable at n, m-n, m value constantly;

h ₁, h ₂, h ₃: transport function.

The advantage of heat performance of solar heat collector rapid measurement device and measuring method is:

Control of the temperature of this device and measuring unit: utilize the flow through heat-transfer working medium import and export temperature of heat collector of platinum-resistance thermometer measurement, environment temperature.Flow measurement and control module are to utilize the flow through flow of heat-transfer working medium of heat collector of electromagnetic flowmeter survey, utilize needle-valve, and by-pass valve is regulated the flow size also makes it keep stable.Solar irradiance measuring unit and tracking cell are used to measure beam radia and scattered radiation, adjust the incident angle of heat collector.Every measurement data can be gathered and put in order to data acquisition system (DAS).Come to determine the thermal behavior of heat collector thus.This measuring method has been considered the thermal capacitance of heat collector itself and the caused heat lag phenomenon of thermal capacitance of the interior water of heat collector in addition, and solar irradiation in the test process, and environment temperature and heat collector inlet temperature are all variable, thereby test is more near the real operating mode of heat collector.Thereby the result who obtains thus is more effective.

Description of drawings

Fig. 1 is a heat performance of solar heat collector rapid measurement device synoptic diagram.

Embodiment

By the test board of Fig. 1 measurement mechanism by heat-transfer working medium forced circulation unit, temperature control unit, flow controlling unit, temperature measurement unit, the flow measurement unit, solar radiation control, measuring unit, 7 parts such as sun location tracking control module are formed.

Water tank 1 is 140 liters of models, one baffle plate 30 is arranged in it, the top connects the filling pipe and first gate valve 3, run-down pipe 4 and heat exchanger 5 are equipped with in water tank 1 side, tapping pipe (being with one second gate valve 6) is equipped with in water tank 1 bottom, and it is connected the 3rd gate valve 7 successively with pipeline, water pump 8 and the 4th gate valve 9, water tank 1 left side connects the 5th gate valve 10 again and connects water circulating pump 11 again, water circulating pump 11 connects a by-pass valve 12 again side by side, water circulating pump 11 connects filtrator 13 then, one flowrate control valve (being needle-valve 14), with flowmeter 2, be connected in the import 17 of heat collector 16 through viewport 15, its outlet 18 connects an air release 19 and the 6th gate valve 20, the 6th gate valve 20 simultaneously again and connect the 7th gate valve 21, the seven gate valves 21 and be connected on the water tank 1.

In import 17 and outlet 18 places first temperature probe 27 and second temperature probe 28 are installed, one pyramometer 24 are installed, a corona 26 is installed in same plane in the centre position of heat collector plane one side.Installation one blower fan 22 and anemoscope 25 near test board.In distance test board 15m, greater than white thermometer screen 23 is installed in the scope of 1m, interior dress is surveyed the thermometer 29 of environment temperature apart from ground.The import 17 and the outlet 18 of heat collector all will be done insulation.

Temperature control unit comprises water tank 1, filling pipe 3 and heat interchanger 5.Temperature measurement unit comprises platinum-resistance thermometer (Pt100 type), and it is used to measure heat collector 16 imports 17, the temperature of outlet 18, and another is used for measures ambient temperature; The flow measurement unit comprises electromagnetic flowmeter (model: COPA-XE DE43F type), be used to measure the flow of heat collector 16; Flow controlling unit comprises that needle-valve 14 is used to regulate flow, water circulating pump 11 (model Wilo-Star-RS 25/6) and water pump 8.Solar radiation control and measuring unit comprise that sunshading board (figure is expression not), pyramometer (model TBQ-2-B) are used to measure the total solar radiation that drops on the heat collector 16.The sun location tracking control module comprises corona 26 rotary stands and angle protractor (figure is expression not).Data acquisition system adopted HP34970A type Hewlett-Packard Acquisition Instrument.

Theoretical modeling is a most important parts of the present invention, and the new model of derivation is as follows:

${\mathrm{\θ}}_0\left(n\right)=\underset{m=0}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\θ}}_i(n-m)h_1\left(m\right)+\underset{m=0}{\overset{N}{\mathrm{\Σ}}}\hat{G}(n-m)h_2\left(m\right)+\underset{m=0}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\θ}}_a(n-m)h_3\left(m\right)$

Wherein: $\hat{G}=G-\stackrel{\‾}{G},$ ${\widehat{\mathrm{\θ}}}_b=T_b-{\stackrel{\‾}{T}}_b,$ ${\widehat{\mathrm{\θ}}}_a=T_a-{\stackrel{\‾}{T}}_a,$ ${\widehat{\mathrm{\θ}}}_i=T_i-{\stackrel{\‾}{T}}_i,$ ${\widehat{\mathrm{\θ}}}_o=T_o-{\stackrel{\‾}{T}}_o$

G: solar irradiance, W/m ²

T _b: the temperature of solar energy evacuated inner glass tube wall, ℃;

T _i: heat collector fluid intake temperature, ℃;

T _a: environment temperature, ℃;

T _o: the heat collector fluid outlet temperature, ℃;

G, T _b, T _i, T _a, T _o: G under the equilibrium state, T _b, T _i, T _a, T _oValue;

N, m-n, m: refer to variable at n, m-n, m value constantly;

h ₁, h ₂, h ₃: transport function.

This model has relaxed the outdoor conditions of heat collector thermal performance test, makes the fate that is fit to test in a year increase greatly; Reduced in the heat collector thermal performance test control requirement to input variable, according to this model in test process except that the flow of the heat collector of flowing through need keep constant, all the other input variables such as solar irradiance, heat collector fluid intake temperature and environment temperature etc. all can change arbitrarily.Utilize the effect of the measurable heat collector heat production under different areas and DIFFERENT METEOROLOGICAL CONDITIONS of this model.

Measuring method of the present invention: the water pump 8 of opening water tank 1 makes a side water that is connected with the water tank outlet concordant with baffle plate 30 tops.Guarantee that systemic circulation water pump 11 suction pressures are constant, help stability of flow, open air release 19 ON cycle water pumps 11, when the water of air release 19 discharges by the time is not with gas, just close air release 19.Just the flow of adjusting system arrives setting value (if the throughput ratio of setting is less, can adjust the aperture of by-pass valve) reach the flow of setting in the further aperture of metering pin valve 14, log-on data Acquisition Instrument (not drawing among the figure) checks whether the work of each sensor is normal then, whether cross the flow of checking this system in 20 minutes during this period of time is stabilized in the flow range of setting, just can begin experiment if flow is suitable, otherwise should readjust flow.(at this moment also available computers control is adjusted flow automatically to setting value) is because requirement of experiment comprises system information as much as possible, in test process, to make and drop on solar irradiation intensity on the heat collector 16, the variation of heat collector temperature in is big as far as possible, so in test process, will raise (covering) shadow shield (not drawing among the figure), and otherwise (shutting) heat interchanger 5 of opening that stops changes it to regulate the heat collector temperature in the working range of not stopping every 5～20 minutes.

Claims (3)

1. heat performance of solar heat collector rapid measurement device, it is characterized in that, one baffle plate (30) is arranged in the water tank of its test board (1), the top connects filling pipe and first gate valve (3), run-down pipe (4) and heat exchanger (5) are equipped with in the side, tapping pipe and the pipeline that has second gate valve 6 is equipped with in water tank (1) bottom, be connected with the 3rd gate valve (7) and water pump (8) on the described pipeline in turn, the 4th gate valve (9), water tank (1) left side connects the 5th gate valve (10) successively, water circulating pump (11), filtrator (13), flowmeter (2), needle-valve (14) and viewport (15), described water circulating pump (11) is connected with by-pass valve (12) side by side, described viewport (15) is connected in the import (17) of heat collector (16), its outlet (18) connects an air release (19), described air release (19) links to each other with the 7th gate valve (21) with the 6th gate valve (20) respectively, described the 7th gate valve (21) links to each other with water tank (1), locate to be equipped with first temperature probe (27) in import (17), locate to be equipped with second temperature probe (28) in outlet (18), in the centre position of heat collector plane one side one pyramometer (24) is installed, one corona (26) is installed in same plane, installation one blower fan (22) and anemoscope (25) near test board, in distance test board 15m, be not less than apart from the ground height white thermometer screen (23) is installed in the scope of 1m, the thermometer (29) of interior dress measures ambient temperature, import of heat collector (17) and outlet (18) all will be done insulation.

2. adopt the measuring method of the measurement mechanism of claim 1, it is characterized in that: open data collecting instrument; The water pump (8) that starts water tank (1) makes stability of flow to guarantee the pressure of water circulating pump (11) suction inlet, starts water circulating pump (11), adjusts the aperture of by-pass valve (12) and needle-valve (14), so that flow is to setting value.

3. measuring method according to claim 2 is characterized in that:

Theoretical model is:

${\mathrm{\θ}}_0\left(n\right)=\underset{m=0}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\θ}}_i(n-m)h_1\left(m\right)+\underset{m=0}{\overset{N}{\mathrm{\Σ}}}\hat{G}(n-m)h_2\left(m\right)+\underset{m=0}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\θ}}_a(n-m)h_3\left(m\right)$

Wherein: $\hat{G}=G-\stackrel{\‾}{G},$ ${\widehat{\mathrm{\θ}}}_b=T_b-{\stackrel{\‾}{T}}_b,$ ${\widehat{\mathrm{\θ}}}_a=T_a-{\stackrel{\‾}{T}}_a,$ ${\widehat{\mathrm{\θ}}}_i=T_i-{\stackrel{\‾}{T}}_i,$ ${\widehat{\mathrm{\θ}}}_o=T_o-{\stackrel{\‾}{T}}_o$

G: solar irradiance, W/m ²

T _b: the temperature of solar energy evacuated inner glass tube wall, ℃;

T _i: heat collector fluid intake temperature, ℃;

T _a: environment temperature, ℃;

T _o: the heat collector fluid outlet temperature, ℃;

G, T _b, T _i, T _a, T _o: G under the equilibrium state, T _b, T _i, T _a, T _oValue;

N, m-n, m: refer to variable at n, m-n, m value constantly;

h ₁, h ₂, h ₃: transport function.

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