Surface Temperature Measurements Research Articles

Effects of Green Roof in Reducing Surface Temperature and Addressing Urban Heat Island in Tropical Climate of Malaysia

Urban heat island (UHI) in cities across Malaysia has worsened due to rapid development and construction. Previous research highlight temperature difference between Putrajaya and its suburban neighbouring area is as high as 5˚C. Green roofs in urban areas can be used as a green intervention strategy to reduce UHI impact by increasing air moisture and surface wetness through its plants, which consequently decreases surrounding air and surface temperature. Green roofs also provide additional insulation that reduces heat transfer into buildings, therefore reducing cooling demand and operational energy in buildings. Conventional building roofs in tropical climate have measured surface temperature up to 60˚C, compared to surrounding irrigated grass and water bodies that are measured as low as 15˚C. This paper compared surface temperatures of green roof and conventional non-green roof case studies in a tropical climate setting, to combat urban heat island effect. A triangulation technique was adopted, using a case study analysis with an in-depth structured interview and physical fieldwork investigation. The findings concluded that green roofs had significantly lower surface temperature compared to non-green flat roof. This paper provides evidence that supports green roof as a green intervention strategy in reducing urban heat island and encourage building designers to maximize under-utilized spaces of roofs to increase urban greenery coverage.

Observing system simulation experiments reveal that subsurface temperature observations improve estimates of circulation and heat content in a dynamic western boundary current

Abstract. Western boundary currents (WBCs) form the narrow, fast-flowing poleward return flows of the great subtropical ocean gyres and are sources of rapidly varying mesoscale eddies. Accurate simulation of the vertical structure, separation latitude, and ocean heat content of WBCs is important for understanding the poleward transport of heat in the global ocean. However, state estimation and forecasting in WBC regions, such as the East Australian Current (EAC), the WBC of the South Pacific subtropical gyre, is challenging due to their dynamic nature and lack of observations at depth. Here we use observing system simulation experiments to show that subsurface temperature observations in a high eddy kinetic energy region yield large improvement in representation of key EAC circulation features, both downstream and ∼ 600 km upstream of the observing location. These subsurface temperature observations (in concert with sea surface temperature and height measurements) are also critical for correctly representing ocean heat content along the length of the EAC. Furthermore, we find that a more poleward separation latitude leads to an EAC and eddy field that is represented with far reduced error, compared to when the EAC separates closer to the Equator. Our results demonstrate the importance of subsurface observations for accurate state estimation of the EAC and ocean heat content that can lead to marine heatwaves. These results provide useful suggestions for observing system design under different oceanographic regimes, for example, adaptive sampling to target high energy states with more observations and low energy states with fewer observations.

Spatial and spectral filtering strategies for surface phosphor thermometry measurements

Intensity-ratio based phosphor thermometry is a well-established technique to obtain surface temperature measurements, which however suffers from important pixel-to-pixel noise, mainly due to the signal-dependent photon shot noise. In order to enhance signal-to-noise ratio levels, spatial filtering is recognized as a common post-processing routine, with the implication of strongly alleviating the spatial resolution (SR) of measurements. In this study, a dataset of phosphorescence images using Mg4FGeO6:Mn4+ thermographic particles and an ICCD camera is constituted. Various spatial filtering strategies are applied to these images, such as software pixel binning, moving average and Gaussian filters, in order to estimate their relative performances in terms of SR and temperature uncertainty. In addition, a Fourier space low-pass Butterworth filter is benchmarked against these common filters. Results show that the pixel binning strategy provides a limited improvement in the temperature uncertainty when compared to the loss in SR. Conversely, the Gaussian and moving average filters are found to effectively enhance the temperature uncertainty, though the 5th-order Butterworth filter is more selective, by providing an excellent mitigation of high-frequency noise with a minor attenuation of low-frequency information. Eventually, a joint spatial-spectral filtering strategy is investigated, which however does not present significant advantages compared to a sole filtering strategy.

Surface temperature measurement of cooling and heating droplets by rainbow refractometry.

Rainbow refractometry was used to measure the temperature and size of transparent spherical particles. In practice, however, there are limitations to the application of heating and cooling droplets, as the temperature measured is neither the average nor the surface or core temperature of the droplet. Reported here is an exploitation of this technique for droplet surface temperature determination. Droplet surface tension was measured by detecting the evolution of interference fringes of oscillating droplets. The dependence of surface tension on temperature facilitated the study of surface temperature of an evaporating droplet with time. Moving ethanol, n-heptane, and n-decane droplets were investigated under heating and cooling conditions. The capabilities and limitations of rainbow refractometry were verified by comparing the droplet temperature values measured directly by rainbow refractometry with the surface temperature.

Surface temperature measurement based on reflectance spectrum of temperature indicating paint and machine learning algorithms

The key to the interpretation of temperature-indicating paint (TIP) is the accurate measurement of color. In this work, combined with the color information carried by the reflectance spectrum, a fiber-based TIP interpretation method is proposed and evaluated. The sub-band statistical feature extraction algorithm (SFEA) is constructed to deal with the high dimensionality and high redundancy of spectra in data processing. During the research, an online TIP temperature interpretation system based on Y-type fiber is designed and implemented. Three types of TIP samples (KN3, KN6, KN8) are employed for testing. The results indicate that the SFEA reduces the influence of light intensity fluctuations on temperature interpretation. And the ambient light has no obvious influence on the measurement accuracy of this system. When the error tolerance is 10 °C, the interpretation accuracy is 99%, 99%, 95% respectively. The method has been tested on V-notch specimen.

Identifying Oceanic Responses with Validated Satellite Observations after the Passage of Typhoons in the Northern South China Sea

Tropical cyclone-induced upwelling has an important influence on ocean temperature and chlorophyll-a (Chl-a) concentrations, which are modified by the existence of mesoscale eddies. This paper investigates the regional dynamics and associated variability in temperature and Chl-a during the passage of three typhoons (Kammuri, Nuri, and Hagupit) with similar tracks in the northern South China Sea (SCS) during 2008 using remote sensing and in situ observations. The measurements of wind and sea surface temperature obtained by a buoy and satellite were found to be similar, and both showed that typhoons have prominent impacts on the ocean’s upper layer. Sea surface cooling is first identified during the passage of each typhoon, particularly on the right side of typhoon tracks. Increased Chl-a concentrations were observed in the surrounding areas after the passage of typhoons Nuri and Hagupit, with large offshore blooms (Chl-a increases of 0.27–0.33 mg m−3) identified along the tracks of Nuri and Hagupit 3 to 4 days after their passage. Such blooms are highly dependent on the cooling associated with typhoon-induced mixing and upwelling. The pre-existing eddies modified the surface variations, and a perfect match was identified between the polarities of the eddies and the ocean surface changes. An anomalously high offshore Chl-a enhancement entrained by a cyclonic eddy occurred along the track of Nuri 4 days after its passage; in this instance, typhoon-induced upwelling was reinforced by the cyclonic eddy. In comparison, typhoon-induced upwelling is inhibited by anticyclonic eddies, resulting in much less prominent changes. The combination of typhoon winds and eddies can modify the productivity of marine phytoplankton, and a comprehensive understanding of typhoon-induced dynamics will aid in understanding ecosystem responses to typhoons.

Quantifying canopy conductance in a pine forest during drought from combined sap flow and canopy surface temperature measurements

• Measurement of canopy temperature using near infrared camera enhances the accuracy of canopy conductance determination. • Isothermal assumption leads to substantial bias in the stomatal conductance determination. • The Penman-Monteith equation applied to the canopy layer and combined with a radiative transfer model provides reliable estimates of canopy conductance. • Canopy temperature of a pinus pinaster stand is strongly coupled with the atmosphere. • The use of an infrared camera improve stomatal conductance estimation. • Isothermal assumption leads to bias in the canopy stomatal conductance determination. • At our site, Penman-Monteith inversion with eddy covariance inputs is not reliable. • The divergence between studied methods is higher when the water stress is low. Precise determination of canopy conductance ( g s ) is needed to quantify the water loss and CO 2 exchange from forest canopies and their response to changing environmental conditions. In this study, we combined measurements of the leaf-to-air vapour pressure difference ( D L ) derived from canopy surface temperature, and tree transpiration to calculate canopy g s in a pine forest at the ICOS site FR-Bil. The period covered was characterized by two consecutive droughts. The inversion of the generalised water transport equation (GT), along with its isothermal simplification (GT’), were used to calculate canopy g s and compared with g s determined from the inversion of the Penman-Monteith equation (PMT). A thermal infrared camera continuously monitored the canopy temperature and allowed to assess the time course of D L with half-hourly resolution. On average a 0.3 °C temperature difference was found between the canopy and surrounding air, with values ranging from − 2 °C to +5 °C depending on the time of day, soil moisture and humidity. The three methods used to calculate g s , GT, GT’ and PMT were in agreement under wet soil and low atmospheric demand, but differences up to 40% were found under water stress conditions when the canopy to air temperature differences led to substantial discrepancies between D L and air saturation vapour pressure deficit at 8.2 m in the crown ( D 8 ). Under such conditions the GT’ method overestimated g s whereas the PMT method was closer from values estimated with the GT method. The contrasted behaviour of the atmospheric exchanges between the tree canopy and the overall ecosystem limits the use of the above canopy flux measurements alone to quantify the response of surface conductance to environmental drivers. Our results also advocate the use of in situ surface temperature measurements to better understand the response of plant canopies to environmental conditions.

State-monitoring and product quality measurement of additively manufactured injection mould inserts

Additive technologies represent a state-of-the-art and innovative way in today’s mould making. They allow production of both metallic and polymeric moulds with relative simplicity and flexibility compared to conventional machining. Despite its possible benefits, this area is scarcely researched. In our work, we analysed in-mould applicability of epoxy-acrylate inserts manufactured by PolyJet technology. We created a comprehensive state monitoring method to quantify important process parameters like cavity pressure, strain and temperature of the inserts. We analysed the effect of holding pressure on the resulting cavity pressure and strain of the insert. We showed that strain of the insert gradually increased after the cycles and we identified characteristic segments of the injection moulding cycle on the strain-time curves. We also applied surface temperature measurements using a thermal imaging camera. The purpose of this measurement was to determine necessary delay time between cycles allowing inserts to cool below heat deflection temperature, so early failure could be prevented. By using thermal imaging camera, we measured cavity surface temperature distribution and demonstrated the effect of low thermal conductivity of the insert material. We also measured thickness and weight variation of injection moulded products to show the effect of holding pressure and mould deformation on final product quality. As we applied higher holding pressures, product mass and average product thickness grew.

An enhanced thin-film resistance temperature detector and its application for catalyst layer surface temperature measurement inside PEMFC

Temperature detection is of vital significance for the thermal management of proton exchange membrane fuel cells (PEMFCs). In this work, a robust Au thin-film resistance temperature detector (RTD) was fabricated based on the micro-electro-mechanical system (MEMS) to achieve temperature monitoring inside PEMFC. Low-temperature heat treatment was carried out to promote the performance of RTD, and was confirmed to help achieve good linearity and small thermal hysteresis. Combined with X-ray diffusion (XRD) Rietveld refinement and morphology analysis, particularly the lattice strain and dislocation calculation, low-temperature heat treatment is supposed to help eliminate lattice defects and residual strains in the film. Subsequently, this prepared RTD was applied to measure cathode catalyst layer (CCL) temperature inside PEMFC under different relative humidity (RH) and current loads. The results show that current loads are positively related to temperature variation. The higher the current, the more Joule and irreversible heat are generated. The RH of anode and cathode has a more complex impact on temperature evolution, depending on the water concentration in the electrode sites, which is not only affected by RH, but also by the oxygen reduction reaction (ORR). Too high water contents in the electrode area would bring about flooding, while too low would result in membrane drying, so both of them cause different levels of ohmic and mass transport loss, hence inducing temperature variations. This work is supposed to benefit the research of RTD enhancement and thermal state inside PEMFC.

Flexible miniaturized thin film thermocouples arrays for high temperature applications

Thin film thermocouples (TFTCs) are critical for surface temperature measurements of hot components in high temperature environments. In this paper, miniaturized Pt/Pt-10%Rh thin film thermocouple arrays were fabricated on flexible Hastelloy substrates by magnetron sputtering. The morphology and microstructure of Al2O3/Y2O3 insulating films were investigated by a field-emission scanning electron microscope with an energy dispersive X-ray spectroscopy system. The thermoelectric performance of the TFTCs arrays was investigated by cyclic calibration and bending tests. During the whole calibration process, the average maximum temperature differences (ΔT′ ) of measuring points 2, 3, and 4 are 637 °C, 617 °C, and 574 °C, respectively, which differ from the maximum temperature difference (ΔT max ) of measuring point 1 by -13 °C, -34 °C, and -76 °C, respectively. The calibration results show that each single measuring point has good repeatability and stability during the five calibration processes, and the temperature difference between multiple measuring points is obvious, stable and reliable. The thermoelectric properties of the thin film thermocouple arrays barely change after 10,000 cyclic bending tests.

FIELD EXPERIMENTATION ON WALL SURFACE TEMPERATURE WITH FABA BRICK IN HOT CONDITIONS

The processing of coal waste into building materials from fly ash bottom ash has been stipulated in Regulation number 22 of 2021 as Non-Hazardous material, with a note that the management requirements must still meet the standards and technical requirements set out and listed in the environmental document approval. Previous studiesstated that one of the physical characteristics of the use of this waste (fly ash bottom ash) can be in improving the quality of construction materials and environmental quality. The research questions of this study are: Does the facing east orientation quantitatively receiving more heat of the morning sun than other orientations? Does FABA brick walls affect the indoor thermal performance? The wall surface temperature measurement is carried out by the field experimentation with extreme climatic conditions, both sunny and rainy weather in 2021. The results of this study found that the surface temperature profile of the brick wall oriented to the east in sunny rainy/cold weather is cooler 2 % compared to the temperature on the western side. The wall surface temperature profile in the morning is 25% warmer than the ambient air temperature in sunny weather and 9% cooler in rainy weather. wall material with FABA brick proves that the orientation, location and character of the microclimate are significant to the thermal value.

Evaluation of the Uncertainty of Surface Temperature Measurements in Photovoltaic Modules in Outdoor Operation.

Faults in photovoltaic modules in operation can lead to power losses. By determining the module surface temperature, hot spots that can potentially cause this power loss can be detected. Temperature measurement by radiation allows a complete, reliable, and fast qualitative determination of hot spots on PV modules in outdoor operation. However, to obtain quantitative values, it is necessary to consider multiple factors: emissivity, reflected radiation, wind speed, intensity, shading, etc. Temperature quantitative measurement evaluation by contact is more studied, although by this technique it is impossible to examine the temperature of the entire module to detect hot spots because it is a point measurement and due to shading caused by the measurement probe on the surface. In this work, a method of temperature measurement by radiation is described, evaluating the uncertainty components, and a comparison is made with temperature measurement by contact on the module rear side points where module heating has been detected, also evaluating the uncertainty components. This comparison of both methods and uncertainty determination allows establishing a methodology in quantitative temperature measurement by radiation in photovoltaic modules in outdoor operation.

Effects of feeding pressures on the flowfield structures of three-dimensional film cooling

A Mach 2.6 annular supersonic nozzle was designed to protect a hypersonic cone. The annular nozzle is able produce tangential cooling film around the cone. Experiments were carried out in a hypersonic wind tunnel under different cooling film feeding pressures and different attack angles. Temperature-sensitive paint (TSP) was used to measure surface temperature of the cone body; schlieren method was applied to visualize the flow structures. TSP results showed that cooling film can obviously decrease surface heating load, but its efficiency was influenced by the angle of attack. Schlieren results showed that the shape of upper-lip shock wave is similar to an arc, and the reflected shock wave is more closer to a straight line; both the tilt rate of upper-lip shock wave and the reflected shock wave were increased exponentially with the rise of feeding pressure; a higher feeding pressure resulted in a larger curvature of upper-lip shock wave; compared with reflected shock wave, upper-lip shock wave and shearing layer were more easily affected by the feeding pressure. With higher feeding pressure, incidence point was moved to the further downstream location, and a fitting formula is given to express the relationship between the position of the shock wave incidence point and the feeding pressure.

The use of infrared thermography to noninvasively measure the surface temperature of polar bears during bouts of social play.

Infrared thermography or thermal imagery is a noninvasive tool that can be used to measure the temperature of surfaces. Typically, thermal imagery is used for construction or military purposes but is increasingly used as a noninvasive tool in wildlife studies. We investigated the use of thermal imagery to measure surface temperature changes as a proxy for energetic expenditure. We measured the surface temperature of polar bear (Ursus maritimus) eyes, while immobilized, to determine whether the eye is a thermal window that can accurately indicate internal temperature. We found a significant difference (2.68 ± 0.41°C) between the surface temperature of the eye measured with thermal imagery and the internal rectal temperature. Additionally, we measured surface temperature changes in polar bears after bouts of social play as a proxy for energy expenditure. Mean temperature of the eye increased by 1.34 ± 0.43°C after social play, indicating that this activity increased energy expenditure. During the fasting season, polar bears rely on fat stores, and any energy expenditure beyond what is required to travel may be costly to their survival, particularly in years of low resource availability. We conclude that thermal imagery is a useful tool to noninvasively investigate the energetics of social play.

Spatial and temporal variability of the physical, carbonate and CO2 properties in the Southern Ocean surface waters during austral summer (2005-2019)

In situ measurements of sea surface temperature (SST), salinity (SSS), Total Alkalinity (AT) and Total Carbon (CT) were obtained during austral summer (mid-February to mid-March) from 2005 to 2019 in the Southern Ocean (SO), along a transect between Hobart, Tasmania and Dumont d’Urville French Antarctic Station. The studied transect is divided in four regions from North to South: the Subtropical Zone (STZ), the Subantarctic Region (SAR), the Antarctic Region (AAR) and the Coastal Antarctic Zone (CAZ). Latitudinal distribution of measured SST, SSS, AT, CT as well as calculated pH, CO2 parameters (seawater fugacity of CO2 (fCO2sw), difference between seawater and atmospheric fCO2 (ΔfCO2), CO2 flux (FCO2)) and satellite-derived Chlorophyll a (Chl-a) are discussed. We show that the variability of physical and carbonate parameters in the STZ and north of the SAR are related to the mesoscale activity. In the CAZ, the freshwater inputs from sea-ice melting strongly impact the variability of all parameters. The comparison between physical and carbonate parameters highlights that AT and CT are directly related to the latitudinal variability of SST and SSS. Study of the CO2 parameters shows that the transect is a sink of CO2 during February and March, with a mean FCO2 of −4.0 ± 2.8 mmol m−2 d−1. The most negative values of FCO2 are found in the STZ and SAR north of 50°S and in the AAR south of 62°S, where biological activity is high. New simple empirical relationships are developed for AT from SST and SSS and for CT using SST, SSS and atmospheric fCO2 (fCO2atm) for the austral summer in the studied area. Using high resolution SSS and SST from the SURVOSTRAL program, trends of AT and CT are determined in the SAR and the AAR from 2005 to 2019. SST, SSS and AT increase over this period in the SAR, which might be explained by the southward migration of the Subtropical Front. In the AAR, no clear trend is detected. CT increases by 1.0 ± 0.2 and 0.8 ± 0.3 μmol kg−1 yr−1 in the SAR and AAR respectively. The trend in the AAR is attributed to the increase in anthropogenic CO2 emissions in the atmosphere while, in the SAR, hydrographic changes also contribute to the increase. Using the coefficient associated with fCO2atm in the equation of CT, we estimate the impact of atmospheric CO2 increase on CT at 1.18 ± 0.14 μmol kg−1 yr−1 and 1.07 ± 0.13 μmol kg−1 yr−1 in the SAR and AAR respectively. Decreases in pH are observed in both regions (−0.0018 ± 0.0001 and −0.0026 ± 0.0003 yr−1 in the SAR and AAR respectively), indicating the sensitivity of surface waters in the area towards the development of ocean acidification processes under rising anthropogenic emissions.

Measured Indoor Environmental Data in a Retrofitted Multiapartment Building to Assess Energy Flexibility and Thermal Safety during Winter Power Outages

The article describes detailed measurements of indoor environmental parameters in a multiapartment housing block located in Milan, Italy, which has recently undergone a deep energy retrofit and is used as a thermal battery during the winter season. Two datasets are provided: one refers to a series of experimental tests conducted by the authors in an unoccupied flat, in which the thermal capacity of the building mass is exploited to act as an energy storage. The dataset reports, with a time step of 10 min, measurements of air temperature, globe temperature and surface temperatures in the analyzed room and data characterizing the adjacent spaces and the outdoor conditions. The second set of data refers to the air temperature monitoring carried out continuously in all the apartments of the apartment block, and hence also during two unplanned heating power outages. The analyzed data show the role of deep renovations in extending the time over which a building can remain in the thermal comfort range after an energy interruption and thus highlight the potential role of retrofitted buildings in delivering energy flexibility services to related stakeholders, such as the occupants, the building manager, the grid operator, and others. Furthermore, the dataset can be used to calibrate an energy simulation model to investigate different demand-side flexibility strategies and evaluate thermal safety under extreme weather events.

Earth observation data sets in monitoring of urbanization and urban heat island of Delhi, India

Rapid urbanization and land use transformation coupled with climate change impact are witnessed for development urban heat island worldwide and make it major environmental concerns for human health. National Capital Region (NCR) is one of the fast sprawling National Capital city of India. The aim of the present study is to explore the spatial changes in major biophysical parameters of city over last 20 years from 2000 to 2020 using satellite data. The spatial variation in the land surface temperature and its relation with Land use, NDVI and Built-up area were evaluated and discussed in the present work. The major changes were observed in minimum and maximum temperature of the city, in 2000 minimum temperature was 23.20 °C and maximum 34.85 °C, which increased to 26.31 and 39.92 °C in 2010; and 31.70 to 44.74 °C in 2020 . Normalized differential vegetation index (NDVI) decrease from 82 to 62%, Non-Vegetated area has reduced to 62% from 82% due to fast urbanization and land transformation in last two decades. Barren and fallow land also reduces about 27% in last two decades and built-up area also shown increasing trend . The spatial changes in biophysical parameter of the city clearly indicated that NDVI, NDBI and Land use/land cover charges are the main driving forces for development of urban heat island in the city and many health issues related to heat waves are already reported in the city along with many other negative impacts on natural landscape and resources. The observations from present work will be very useful scientific information to understand the causes of elevated land surface temperature and mitigation measures. Results could be used by policy makers to develop the suitable model for long term sustainability of the cities.

Stretchable electronic skin patch with strain isolation for the simultaneous measurements of surface electromyography and temperature

Stretchable electronic skin patches have continuously attracted the attention of researchers and clinicians due to their potentials in medical applications. Despite the remarkable progress of electronic skin patches with diverse sensor modalities for regions undergoing small deformations, the electronic skin patch in a stretchable format for regions requiring large strain accommodations has far less been explored. Here, we report a stretchable electronic skin patch with strain isolation for the simultaneous measurement of surface electromyography (sEMG) and temperature. The electronic skin patch consists of two mesh-like sEMG electrodes and one resistance temperature sensor on a compliant substrate with programmable stiffness induced by the spatioselective ultraviolet exposure. This construct allows for mechanical softness of electrodes for an intimate attachment to skin and isolation of deformation-induced disturbances and damages to the temperature sensor. Experimental and numerical studies reveal the design, fabrication and operation of the skin patch. Demonstration of the skin patch with strain isolation on the lumbar muscle groups during the trunk flexion, which may introduce a 20% strain level, illustrates its robust capabilities for the comprehensive assessment of muscle activities with possibilities to study the temperature effect on sEMG signals. The results reported here provide important inspiration for constructing multifunctional electronic skin patches with a wide range of applications such as health-monitoring devices, wearable human-machine interface and clinical muscle function evaluation.

Flux–Gradient Relationships Below 2 m Over a Flat Site in Complex Terrain

The surface–atmosphere turbulent exchange fluxes are experimentally determined using the eddy-covariance method. Their estimation using profiles of the variables of interest is a less costly alternative, although restricted to certain ranges of stability and assumed to hold for relatively flat and homogeneous terrain. It relays usually on the prescription of the roughness lengths for momentum, heat and matter, the latter two being adjustable parameters with unclear physical significance. The relations are derived with data from screen level to a few tens of metres upward. The application of these expressions using data only at one level in the surface layer implies assuming zero wind speed and the land surface temperature at their respective roughness lengths. The latter is a quantity that experimentally can only be determined radiatively with a substantial uncertainty. In this work the flux-profile relationships for momentum and sensible heat are assessed over a flat site in moderately inhomogeneous complex terrain in the southern pre-Pyrenees, using data between 2 m and the surface. The main findings are that (i) the classical expressions hold in the daytime for most of the dataset, (ii) the iterative estimations using the Obukhov length and the direct ones using the bulk Richardson number provide very similar results, (iii) using a second observation of temperature avoids a radiometric measure of land surface temperature and the prescription of a thermal roughness length value, (iv) the estimations over wet terrain with high irradiance depart largely from observations.

Internal temperature prediction model of the cylindrical lithium-ion battery under different cooling modes

With the popularity of electric vehicles, lithium-ion batteries are widely used. As a temperature-sensitive component, the performance, life span, and safety of lithium-ion batteries are affected by their working temperature. Therefore, the monitoring of lithium-ion battery temperature is of great significance for electric vehicles. Currently, the temperature monitoring methods are mainly based on the measurement of battery surface temperature. It is difficult to obtain the more important internal temperature that reflects the actual electrochemical reaction status inside the battery. Herein, a prediction model for cylindrical 18,650 lithium-ion batteries is established to reveal the internal temperature under various boundary conditions. Firstly, T-type thermocouples are inserted into the battery to obtain the internal and surface temperature. The characteristics of the battery temperature variation at different discharge rates under different cooling conditions are analyzed in detail. Then, the calculation model of the battery internal temperature under different cooling modes is established by using the thermal network method. Finally, the accuracy of the prediction model is verified by the experimental data. The results show that the internal temperature at the positive terminal is higher than that in other parts. From the perspective of safety, this temperature can be used as a target parameter for the battery thermal management system and is also suitable as a warning parameter to monitor the battery thermal runaway. The battery internal temperature prediction model can achieve a high calculation precision based on the thermal network method. The absolute and mean square deviations can be controlled within 1.5 °C and 0.8 °C under the discharge rate of up to 1.5C and 1C pulse discharge. It provides high precision and reliable calculation method for the internal temperature prediction of power batteries in electric vehicles under daily driving with low discharge rates.