Assessing the influence of operating conditions and thermophysical properties on the accuracy of in-situ measured U -values using quantitative internal infrared thermography

Tejedor, Blanca; Casals, Miquel; Gangolells, Marta

doi:10.1016/j.enbuild.2018.04.011

Cited by 46 publications

(36 citation statements)

References 30 publications

(51 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In southern European countries, the literature review suggested some recommendations to conduct measurements in existing buildings by NDT methods: (i) tests should be conducted on early morning or after the sunset in order to achieve steady-state conditions [20][21][22]; (ii) a correct estimation of the heat transfer coefficients and parameters related to the calibration of the IR camera should be required [1]; (iii) IRT survey should be performed when stable weather conditions can be guaranteed in-prior [1]; (iv) the metering section of the HFM should be defined by a qualitative inspection prior to the experimental campaign [44]; (v) the temperature gradient across the building envelope should range from 7 to 10 • [32]; (vi) the type of heating unit can influence the results, since non-homogeneous heat fluxes and fluctuations of wall temperatures could be attributed to air peak currents [20]. However, some of the mentioned requirements can be a challenging task in Northern European countries where the climatic conditions are often more extreme and more variable.…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, the thermal gradient through the wall was within the range of 7-10 • C in the case of test without heating. The deviation between the theoretical and measured U-value was 1.24 up to 3.97% for a test duration of 2-3 h. Further research of the same authors allowed evaluating the impact of operating conditions and thermo-physical properties on the quality of the results [32] as well as verifying if non-transient regime have been achieved during in situ tests [33]. The results pointed out that the most favorable range of temperature gradient between inside and outside environment was from 7 to 16 • C, considering unheated buildings and heavy and poorly insulated walls.…”

Section: Quantitative Infrared Thermography Under Steady-state Conditmentioning

confidence: 94%

See 1 more Smart Citation

Impact of Stationary and Dynamic Conditions on the U-Value Measurements of Heavy-Multi Leaf Walls by Quantitative IRT

et al. 2020

Self Cite

View full text Add to dashboard Cite

Infrared thermography (IRT) has become a commonly applied non-destructive testing method for assessing building envelopes. Like any diagnosis tool, IRT requires an appropriate experience and principle understanding, mainly when the method is used for quantitative analyses. The challenges of the IRT often deal with the dynamic properties of building partitions. Climatic conditions have a certain variability, and the accumulated energy storage in the building components can affect their temperature as well as the calculated thermal performance. This paper aims to analyze how stationary and dynamic regimes of a quantitative IRT test could impact the measured thermal transmittance of heavy multi-leaf walls. Investigation in two European countries with different climatic conditions are reported. In this way, it is discussed which boundary conditions should be guaranteed to provide reliable information about a building envelope using quantitative IRT. In order to check the quality of the measurements, the heat flux meter (HFM) method was also implemented, following the ISO 9869. The research revealed that it could be possible to use short-lasting tests in the climatic conditions of Southern Europe, while long-term tests should be implemented in Northern European countries where climatic conditions are less regular.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Quantitative Infrared Thermography Under Steady-state Conditmentioning

confidence: 94%

Impact of Stationary and Dynamic Conditions on the U-Value Measurements of Heavy-Multi Leaf Walls by Quantitative IRT

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Then, the state and observation equations can be expressed as in Equations (11) and (12), respectively:…”

Section: Parameter Estimationmentioning

confidence: 99%

“…We focus on non-destructive methods. One non-destructive method utilizes infrared cameras [8][9][10][11]. Tejedor et al [10] built a measuring system composed of an IR camera, a reflector, and a blackbody and achieved short-time measurements of 2-3 h. Their results show a deviation of 3-4% from literature values.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Building Thermal Performance Using Simple Sensors and Air Conditioners

Sakuma

Nishi

2019

Energies

View full text Add to dashboard Cite

Energy and environmental problems have attracted attention worldwide. Energy consumption in residential sectors accounts for a large percentage of total consumption. Several retrofit schemes, which insulate building envelopes to increase energy efficiency, have been adapted to address residential energy problems. However, these schemes often fail to balance the installment cost with savings from the retrofits. To maximize the benefit, selecting houses with low thermal performance by a cost-effective method is inevitable. Therefore, an accurate, low-cost, and undemanding housing assessment method is required. This paper proposes a thermal performance assessment method for residential housing. The proposed method enables assessments under the existing conditions of residential housings and only requires a simple and affordable monitoring system of power meters for an air conditioner (AC), simple sensors (three thermometers at most), a BLE beacon, and smartphone application. The proposed method is evaluated thoroughly by using both simulation and experimental data. Analysis of estimation errors is also conducted. Our method shows that the accuracy achieved with the proposed three-room model is 9.8% (relative error) for the simulation data. Assessments on the experimental data also show that our proposed method achieved Ua value estimations using a low-cost system, satisfying the requirements of housing assessments for retrofits.

show abstract

“…Using infrared cameras: This approach uses the infrared thermovision technique (ITT) [19][20][21][22] to analyze the surface temperature of the envelope. The U-value of the building envelope can be calculated using the temperature information and the total heat transfer coefficient.…”

mentioning

confidence: 99%

The Feasibility of Improving the Accuracy of In Situ Measurements in the Air-Surface Temperature Ratio Method

et al. 2018

View full text Add to dashboard Cite

This paper reports on a feasibility study conducted to improve the in situ measurement accuracy of the air-surface temperature ratio (ASTR) method. The measured relative error rate was analyzed using the ISO 6946 [7.69 W/(m2·K)] and Korea Energy Saving Design Standard [9.09 W/(m2·K)] indoor total surface heat transfer coefficients. The relative error rate was analyzed according to fluctuations in outdoor temperature data. The relative error rate obtained using the ISO 6946 standard was analyzed about 6.3% and that obtained using the Korea Energy Saving Design Standard was about 9.5%. The relative error rate measured for outdoor temperature fluctuations of less than 1 K was about 4.62% and that for temperatures greater than 1 K was about 14.31%. The study results confirmed the cause of the error in the measurement of the ASTR. It was also found that the accuracy of the latter can be improved when the ISO 6946 indoor total surface heat transfer coefficient is applied and when outdoor temperature fluctuations less than 1 K are sampled and analyzed.

show abstract

Assessing the influence of operating conditions and thermophysical properties on the accuracy of in-situ measured U -values using quantitative internal infrared thermography

Abstract: Portal del coneixement obert de la UPC http://upcommons.upc.edu/e-prints Aquesta és una còpia de l'author's final draft d'un article publicat a Energy and Buildings.

Cited by 46 publications

References 30 publications

Impact of Stationary and Dynamic Conditions on the U-Value Measurements of Heavy-Multi Leaf Walls by Quantitative IRT

Impact of Stationary and Dynamic Conditions on the U-Value Measurements of Heavy-Multi Leaf Walls by Quantitative IRT

Estimation of Building Thermal Performance Using Simple Sensors and Air Conditioners

The Feasibility of Improving the Accuracy of In Situ Measurements in the Air-Surface Temperature Ratio Method

Contact Info

Product

Resources

About