CN104964999A - Device and method for testing equivalent thermal resistance of reflective thermal insulation coating material - Google Patents

Abstract

The invention discloses a device and a method for testing the equivalent thermal resistance of a reflective thermal insulation coating material. The method comprises the following steps of simulating the sunlight irradiation of a thermometer through light and heat emitted by an infrared heating lamp by utilizing hot-box testing; analyzing the power saving rate of hot boxes for the reflective thermal insulation coating material by testing the power consuming rate of different hot boxes, and calculating to obtain an equivalent thermal resistance value of the reflective thermal insulation coating material. The method is simple and feasible, the energy conservation effect of the reflective thermal insulation coating material can be effectively represented, the problem that a conventional method for calculating the equivalent thermal resistance of the reflective thermal insulation coating material is too complicated is solved, and the method can be used for calculating the equivalent thermal resistance value of the reflective thermal insulation coating material and evaluating the energy conservation effect in the field of building energy conservation, and can also be popularized to test other wall energy conservation materials in the field according to practical situations.

Description

A test device and method for equivalent thermal resistance of reflective heat-insulating coating

technical field

The invention relates to a thermal resistance test device and method, in particular to a test device and method for the equivalent thermal resistance of reflective heat-insulating coatings. Background technique

With the popularization and application of architectural reflective heat insulation coatings, a series of relevant standards have been issued in our country. In September 2008, the Ministry of Housing and Urban-Rural Development issued the construction industry standard "Building Reflective Thermal Insulation Coatings" (JG/T 235-2008), which mainly stipulates the thermal insulation performance indicators of 4 products, mainly sunlight Reflectance ratio, hemispherical emissivity, thermal insulation temperature difference and thermal insulation temperature difference attenuation, and introduce the method of testing the thermal insulation temperature difference in its hot box. However, the heat insulation temperature difference index has higher requirements on the simulated light source. The wavelength of the simulated light source should be in the visible light region and near-infrared light region with a wavelength of 0.4-2.5 μm as much as possible, and the different model sizes will affect the heat insulation temperature difference. Therefore, it cannot be promoted as an effective energy-saving effect evaluation index. "Reflective heat insulation coatings for buildings" (GB/T 25261-2010) puts forward the concept of equivalent thermal resistance of reflective heat insulation coatings, but it only gives the calculation method of reflective heat insulation coatings in the informative appendix, which requires It is inconvenient to call the annual meteorological database in various places. At present, there is no complete, convenient and effective test method for the equivalent thermal resistance of reflective heat insulation coatings in the current specification.

Contents of the invention

The purpose of the present invention is to provide a testing device and method for equivalent thermal resistance of reflective heat-insulating coatings to achieve convenient and effective acquisition of equivalent thermal resistance of reflective heat-insulating coatings.

The test device for the equivalent thermal resistance of reflective heat-insulating coatings of the present invention comprises four boxes of equal size, 6 walls of each box are gypsum boards of the same thickness, and one of the boxes is a reference thermal box CKX box The 6 sides of the inner wall of the second box are evenly coated with reflective heat insulation paint of the same thickness, which is the TKY box body of the paint heat box, and the 6 sides of the outer wall of the third box are coated with extruded boards of the same thickness, which is extruded board For the JBB box of the hot box, polystyrene boards of the same thickness are pasted on the 6 sides of the outer wall of the fourth box, which is the JBB box of the polystyrene board hot box; there is an infrared heating lamp at the center of the bottom of each box, and each box There is a thermostat and an intelligent power measuring instrument outside the body, the thermostat is connected with the infrared heating lamp in the box, and the sensor probe of the thermostat is set in the corresponding box 1/3~1/2 away from the top of the box At the place, the intelligent power measuring instrument monitors the power consumption of the infrared heating lamp in the box and transmits the data to the computer. All the gaps on the four boxes are sealed with glass glue.

The method for testing the equivalent thermal resistance of the reflective heat-insulating coating with the above-mentioned device comprises the following steps:

1) Power consumption test: Set the temperature of the thermostats in the four cabinets to 36°C, and keep the temperature difference between the inside and outside of the cabinet above 10°C. The smart power meter records the power consumption of the corresponding infrared heating lamps, and obtains the infrared lamps in the four cabinets. The power consumption curve of the heating lamp;

2) Calculating the stable value of the power-saving rate: taking the CKX box as a reference, the power-saving rate curves of the other three boxes are obtained from the power consumption curves of the infrared heating lamps in the four boxes. The calculation formula is as follows:

Among them, w is the power saving rate of the cabinet at time t, Q is the power consumption of the cabinet at time t, and Q _CKX is the power consumption of the CKX cabinet at time t;

Fit the energy saving rate curves of TKY, JBB, and JSB boxes respectively to obtain their corresponding energy saving rate stable values A, B, and C;

3) Calculate the thermal resistance of the box: calculate the thermal resistance R1, R2, R3 of the gypsum board used in the CKX box, the polystyrene board used in the JBB box, and the extruded board used in the JSB box. The calculation formula is: R=d/λ, Where d is the thickness of the corresponding material, λ is the thermal conductivity of the corresponding material; calculate the thermal resistance r1, r2 and r3 of the CKX box, JBB box, and JSB box, r1=R1, r2=R2+R1, r3=R3+ R1;

4) Calculate the equivalent thermal resistance of the coating: Fit the three points (0, r1), (B, r2), and (C, r3). When the correlation is greater than 0.9, the equivalent box thermal resistance and power saving are obtained Using the interpolation method to obtain the thermal resistance value r4 of the cabinet from the stable value A of the power-saving rate of the TKY cabinet, subtract the thermal resistance R1 of the gypsum board to obtain the equivalent thermal resistance of the reflective heat-insulating coating r, r=r4-R1.

Beneficial effects of the present invention:

This device uses the light and heat emitted by the infrared heating lamp to simulate sunlight to irradiate the box, obtain the power consumption of different heat boxes, analyze and calculate the power saving rate of the heat box of the reflective heat insulation coating, and then calculate the reflective heat insulation coating The equivalent thermal resistance value, the method of the present invention is simple and feasible, and can effectively characterize the energy-saving effect of the reflective heat-insulating coating, solves the problem that the current method used to calculate the equivalent thermal resistance of the reflective heat-insulating coating is too cumbersome, and can be used for building energy saving The calculation of the equivalent thermal resistance value of the reflective heat-insulating coating in the field and the evaluation of the energy-saving effect can also be extended to the test of other wall energy-saving materials in the field according to the actual situation.

Description of drawings

Fig. 1 is a schematic diagram of the device structure of the present invention.

In the figure, 1 is the cabinet, 2 is the sensor probe of the thermostat, 3 is the thermostat, 4 is the intelligent electricity measuring instrument, 5 is the infrared heating lamp, and 6 is the computer.

Figure 2 shows the power consumption curves of the four cabinets.

Figure 3 is the power saving rate curves of TKY cabinets, JSB cabinets and JBB cabinets.

Figure 4, Figure 5, and Figure 6 are the comparison charts of the fitting results and power saving rate curves of the TKY cabinet, JSB cabinet and JBB cabinet respectively.

Figure 7 is a fitting curve of the relationship between power saving rate and thermal resistance value.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below in conjunction with accompanying drawings.

The reflective heat-insulating coating used in this example has a density of 37kg/m ³ , a solar reflectance of 0.84, and a hemispherical emissivity of 0.84.

With reference to Fig. 1, the test device of the equivalent thermal resistance of the reflective heat-insulating coating of the present invention comprises four equal-sized casings 1, the internal dimensions of the casings are 900mm * 900mm * 900mm, and the 6 walls of each casing are thickness 12mm gypsum board, one of the boxes is the reference heat box CKX box, the second box is evenly coated with reflective heat insulation paint with a thickness of 0.5mm on the 6 sides of the inner wall, which is the paint heat box TKY box, and the third box Extruded board with a thickness of 25mm is pasted on 6 sides of the outer wall, which is the extruded board hot box JSB box, and polystyrene board with a thickness of 20mm is pasted on 6 sides of the fourth box’s outer wall, which is the JBB box of the polystyrene board hot box; There is an infrared heating lamp 5 with a power of 150W at the center of the inner bottom of each cabinet 1, and a thermostat 3 (model menred E51.716) and an intelligent power measuring instrument 4 ( S350 type), the thermostat 3 is connected with the infrared heating lamp 5 in the box, the sensor probe 2 of the thermostat is set in the corresponding box at a distance of 300mm from the top of the box, and the opening of the infrared heating lamp 5 can be automatically adjusted through the thermostat 3 In order to maintain the set temperature in the heating box, the smart power measuring instrument 4 monitors the power consumption of the infrared heating lamp 5 in the box, and transmits the data to the computer 6. All the gaps on the four boxes are sealed with glass glue. seal.

1) During the power consumption test, the temperature of the temperature controller in the box is set to 36°C, and one vertical air conditioner is installed in the test room to balance the indoor temperature. The windows of the test room are closed with sunshade curtains to avoid external solar radiation as much as possible impact on the experiment. During this test period (summer), the set temperature in the room is 26°C, that is, to maintain a temperature difference between the inside and outside of the hot box above 10°C. The power measuring instrument records the power consumption every 1 minute, and the test is carried out for 36 hours.

The power consumption of each hot box is shown in Figure 2. It can be seen that during the entire 36-hour test process, due to the irradiation of the heating lamp, the power consumption of the four hot boxes increased almost linearly. During the time period when the lamp is not heating, the power consumption is in a stable state. Comparing the 4 hot boxes, during the whole test process, the power consumption from high to low is CKX, JBB, TKY, and JSB. By the time of 36 hours of testing, the power consumption of CKX, JBB, TKY, and JSB were 3.70 and 2.66 respectively. .

2) In order to intuitively compare the change of the electric rate of each heating box with time, take CKX as a reference, and calculate according to the following formula:

Among them, w is the power saving rate of the cabinet at time t, Q is the power consumption of the cabinet at time t, Q _CKX is the power consumption of CKX cabinet at time t; the power saving rate of the other cabinets is calculated over time The change curve is shown in Figure 3.

In order to select the power saving rate in the stable stage of the hot box, use origin8.6 to fit the power saving rate curves of TKY, JSB, and JBB three boxes respectively. In order to ensure the reliability of the fitting results and the real data comparison results, No filtering is performed. The comparison between the fitting results and the real experimental data is shown in Fig. 4-6 respectively.

It can be seen from the fitting results that the power-saving rates W _TKY , W _JSB , and W _JBB of the three cabinets are all in the form of an exponential function with the test time t:

                                      

The goodness of fit of the three were 0.949, 0.908, 0.948 respectively; the sum of squared deviations were 2.73E-4, 1.13E-4, 1.42E-4 respectively. The fitting accuracy is high, the error is small, and the fitting value is relatively close to the real data of the experiment. Observing the exponential function, it can be seen that with the accumulation of test time, the power saving rates W _TKY , W _JSB , and W _JBB are 46.05 when they reach a stable value. %, 59.16%, 31.49%.

3) Since the thermal conductivity of the three materials (extruded board, polystyrene board, and gypsum board) is known, their corresponding thermal resistances can be calculated, as shown in Table 1.

Table 1 Thickness and thermal resistance of three materials

Therefore, the thermal resistance values and power saving rates corresponding to the three cabinets of CKX, JSB, and JBB can be listed in Table 2:

Table 2 Power saving rate and thermal resistance of the three cabinets

Hot box number JSB JBB CKX Power saving rate (%) 59.16 31.49 0 Thermal resistance (equivalent thermal resistance) (m ² ·K/W) 0.869 0.512 0.036

Note: The thermal resistance (equivalent thermal resistance) here is the thermal resistance of each box, that is, the sum of the thermal resistance of the gypsum board and the corresponding material thermal resistance.

4) The thermal resistance values and power-saving rates corresponding to the CKX, JSB, and JBB thermal boxes are known. The thermal resistance values and power-saving rates are quantitative indicators of the thermal insulation performance of materials. Since the power-saving rate of TKY thermal boxes has been measured So, try to calculate the equivalent thermal resistance value of the reflective thermal insulation coating by interpolation method, using the correlation between thermal resistance value and power saving rate. Specifically:

 The three points formed by the power-saving rate and thermal resistance corresponding to the three boxes of CKX, JSB, and JBB are fitted, and the fitting curve is obtained as shown in Figure 7. The correlation coefficient is 0.996, and the interpolation method is applicable. The relationship function between power saving rate x and thermal resistance y can be obtained, y=0.0141x+0.0462, then the equivalent thermal resistance value of the reflective thermal insulation coating can be calculated by interpolation method.

The thermal resistance of the TKY box is 0.0141×46.05+0.0462=0.696m ² ·K/W, so the equivalent thermal resistance of the reflective thermal insulation coating is 0.696-0.036=0.66 m ² ·K/W.

Claims (5)

1. the proving installation of a reflective heat-insulation paint equivalent thermal resistance, it is characterized in that, comprise the casing (1) that four grades are large, 6 walls of each casing are the plasterboard of same thickness, wherein a casing is reference thermal case CKX casing, second cabinet wall 6 evenly scribbles the reflective heat-insulation paint of same thickness, for coating hot case TKY casing, the extruded sheet of same thickness is posted in 3rd cabinet exterior 6 face, for extruded sheet hot case JSB casing, the styrofoam of same thickness is posted in 4th cabinet exterior 6 face, is styrofoam hot case JBB casing; Every casing (1) inner bottom part center is provided with a heat lamp (5), a temperature controller (3) and an Intelligent electric power quantity metering instrument (4) is equipped with outside every casing (1), temperature controller (3) is connected with heat lamp in case (5), the sensor probe (2) of temperature controller is arranged in corresponding casing apart from case top 1/3 ~ 1/2 place, the power consumption of the heat lamp (5) in Intelligent electric power quantity metering instrument (4) monitoring case, and these data are transferred to computer (6), all gaps on four casings all seal with glass cement.

2. the proving installation of reflective heat-insulation paint equivalent thermal resistance according to claim 1, is characterized in that, four described casings, each casing is of a size of 900mm × 900mm × 900mm.

3. the proving installation of reflective heat-insulation paint equivalent thermal resistance according to claim 1, is characterized in that, the described power being placed in the heat lamp in every casing is 150W.

4. the proving installation of reflective heat-insulation paint equivalent thermal resistance according to claim 1, is characterized in that, described plasterboard thickness is 12mm, and reflective heat-insulation paint thickness is 0.5mm, and extruded sheet thickness is 25mm, and styrofoam thickness is 20mm.

5. the method for the device to test reflective heat-insulation paint equivalent thermal resistance according to any one of claim 1-4, is characterized in that, comprise the steps:

1) power consumption test: temperature controller temperature in four casings is set to 36 DEG C, keep casing internal-external temperature difference more than 10 DEG C, the electricity consumption situation of the corresponding heat lamp of Intelligent electric power quantity metering instrument record, obtains the power consumption curve of heat lamp in four casings;

2) calculate power saving rate stationary value: with CKX case for reference, obtained the power saving rate curve of other three casings by the power consumption curve of heat lamp in four casings, computing formula is as follows:

Wherein, w is the power saving rate of casing t, and Q is the power consumption of this casing t, Q _cKXfor the power consumption of CKX casing t;

To the power saving rate curve of TKY, JBB, JSB tri-casings respectively matching obtain its corresponding power saving rate stationary value A, B, C;

3) casing thermal resistance is calculated: calculate CKX casing plasterboard used, JBB casing styrofoam used, the thermal resistance R1 of JSB casing extruded sheet used, R2, R3, computing formula is: R=d/ λ, and wherein d is respective material thickness, and λ is the coefficient of heat conductivity of respective material; Calculate CKX casing, JBB casing, the thermal resistance r1 of JSB casing, r2 and r3, r1=R1, r2=R2+R1, r3=R3+R1;

4) coating equivalent thermal resistance is calculated: to (0, r1), (B, r2), (C, r3) three points do matching, when correlativity is greater than 0.9, and the relation function of the casing thermal resistances such as acquisition and power saving rate stationary value, method of interpolation is adopted to be obtained the thermal resistance value r4 of this casing by the power saving rate stationary value A of TKY casing, deduct the thermal resistance R1 of plasterboard, obtain the equivalent thermal resistance r of reflective heat-insulation paint, r=r4-R1.