Internal Surface Temperature Research Articles

Effect of Green Roofs on the Thermal Environment of Prototype Broiler Houses

The management of thermal environments in animal production facilities presents significant challenges, requiring continuous adjustments to meet animals’ physiological needs. This study evaluated the effects of green roofs on the thermal environment and comfort indices in small-scale poultry house prototypes, comparing facilities with and without green roof installations. The research tested various roof types (ceramic, fiber cement, and metal) combined with emerald grass (Zoysia japonica) green roof systems. Parameters measured included air temperature, relative humidity, internal roof surface temperature, Temperature and Humidity Index (THI), Black Globe Humidity Index (BGHI), Human Comfort Index (HCI), and Thermal Radiation Load (TRL) under both open and closed conditions. Results showed that green roofs reduced indoor air temperature by up to 2.4 °C in open prototypes and 10.6 °C in closed prototypes during peak heat periods. In combinations using green roofs with fiber cement tiles, internal roof surface temperature decreased by 24.0 °C in open prototypes and 27.0 °C in closed configurations. The implementation of green roofs resulted in THI reductions of 2.3 and 8.1 units in open and closed prototypes, respectively, BGHI decreases of 2.8 and 11.3 units, and TRL reductions of 21.0 W/m2 and 74.0 W/m2. HCI measurements confirmed improved thermal comfort conditions with green roof installations in both settings. This study concludes that green roofs effectively enhance the thermal environment by reducing bioclimatic indices during hot periods while maintaining stable conditions during cooler weather, thereby improving overall thermal comfort in animal facilities.

Concrete refuges and the influence of temperature on artificial refuge occupation by terrestrial lizards

ABSTRACT Artificial refuges are commonly used to sample small reptiles and to provide supplementary shelter. For refuges to be effective, they should be safe and acceptable to reptiles. Current designs used for New Zealand lizards are vulnerable to trampling and degradation, restricting where they can be used without risk to lizards. We tested the usage of a new trampling-resistant concrete refuge, containing an internal crevice and basking ledge, by terrestrial lizards on the Port Hills in Canterbury, South Island. Twice a month we inspected 40 refuges on 20 occasions over one year which resulted in 420 gecko and 39 skink encounters. Geckos consistently used refuges throughout the year while skinks were infrequently found. Internal refuge surface and ambient air temperature data suggests that both overnight and day-time temperatures in the refuges were favourable for year-round occupation by geckos at the study site. Due to the low number of skinks, their occupancy was not analysed. Our refuge design appears to be a robust and effective design, particularly for crevice-dwelling geckos in trampling-prone and rocky habitats. Additional research is needed to investigate gecko movements in refuges at more extreme temperatures, test our design on other reptile species and assess potential restoration benefits. Zoobank LSID urn:lsid:zoobank.org:pub:71482E37-D73D-4362-AAE8-4AA15BE33A7F.

Incorporating multi-source uncertainties in fast building wall thermal resistance estimation through physics-based and multi-fidelity statistical learning models

Meta-modelling and Bayesian inversion technique are proposed for fast and accurate in-situ estimation of the total thermal resistance (RTot) of walls using non-intrusive wall instrumentation. Various sources of uncertainties are taken into account to provide an enhanced credible interval for the thermal resistance estimate. In the considered protocol, a small zone of the internal surface of the wall is excited by a prototype to get faster in situ estimation and to limit the influence of external weather conditions. To be independent of the heat transfer coefficients and of the misknown layer thicknesses, which are difficult to estimate, we use herein the measurements of internal and external surface temperatures as boundary conditions in a thermal direct problem reformulated. A meta-model of the thermal model is created based on a statistical multi-fidelity approach with two levels of fidelity, Resistance-Capacitance (RC) and 1D models, to achieve the Bayesian estimation of the total thermal resistance in a reasonable computation time. The RTot estimation method is applied to realistic internal insulated walls (IIW), from poorly to highly insulated, under different weather conditions. Several numerical tests are carried out and credible intervals are provided to study the importance of the wall initial condition, the excitation time and the instrumentation. Finally, an experimental application is conducted using real measurements on an internal insulated wall (IIW) in Nancy (France). The obtained experimental results show that, in a short excitation time (10h) with a reduced instrumentation, the proposed method accurately estimates the minimum wall thermal resistance. For a standard wall of about 4 m2 K/W, a relevant estimate of RTot with a relative deviation less than 10% can be achieved by using a polynomial initial temperature profile proposed in this study, sufficient measurements and an excitation time of 3 days. This study thus offers prospects for improved energy assessment of buildings before and after renovation.

Mould Risk in Technical Room in Four Underground Water Reservoirs

Abstract This conference article analyses the indoor climate of a technical room in four underground water reservoirs. This indoor climate with minimal input energy is specific by high relative humidity and low air temperature, as shown in the experimental measurement. The unsteady 2D numerical simulation of the detail section (partly sub-terrain peripheral wall and floor) in software Calculation Area 4.0e calculates fluctuation of internal surface temperature and relative humidity. Finally, the empirical predictive Finnish VVT model predicts the seasonal mould risk on the internal surface of the peripheral wall.

An experimental and numerical investigation of the thermal performance of phase change materials in different triple-glazed window configurations

Phase Change Materials (PCM) may be excellent thermal insulation due to their poor conductivity and high heat capacity. Researchers are adding PCM to windows. This integration modifies internal surface temperatures and delays peak temperatures to improve indoor thermal comfort. This work investigates experimentally and numerically the impact of the different filling materials in four Triple Glazed Windows (TGW) configurations in an Iraqi environment: the first window filled two cavities with air (standard); the second window has one cavity filled with a PCM and the other with air; the third window has blinders with various tilt angles in one cavity and PCM in the other cavity; and in the fourth window, both cavities are filled with PCM. Numerically utilizing Computational Fluid Dynamics to evaluate the thermal performance of TGW. In August, when the solar radiation was at its maximum (623 W/m2), the results showed that the peak interior surface temperature dropped by 4.51, 13.28 and 11.53 % in the TGW configurations (PCM-air), (blinder-PCM), and (PCM-PCM), compared to the standard TGW. The fourth window increased the time lag by 2 h, effectively shifting the load and in the third window, the best tilt angle blinder is 45°

Impacts of installation methods on the thermal performance of lightweight exterior cladding panels incorporating PCM: An experimental evaluation

Innovative cladding panels were developed by integrating phase change material into foamed concrete (PCMFC). The panels can be installed on walls via the wet method using cementitious/specialized adhesives or the dry method using special tools to mount the panels. The dry method creates an air cavity separating the panels from the wall, which can be of different sizes, either ventilated or unventilated. This study investigates the impacts of installation methods on the thermal performance of walls finished with PCMFC cladding panels. Experimental testing was conducted using three cells under actual weather conditions: a reference cell with cement render, a cell with PCMFC panels installed using the wet method, and a cell with PCMFC panels installed using different alternatives of the dry method. The results revealed improved performance for the dry method, showcasing reductions of about 7.10 °C in peak internal surface temperature (TSᵢ) with a 5 mm air cavity compared to the reference cell, while the reduction raised to about 8.70 °C by increasing the cavity size to 20 mm, and reached about 9.75 °C when permitting free ventilation inside the cavity. These reductions in peak TSᵢ were higher by about 1.14 °C, 1.79 °C, and 2.76 °C, respectively, compared to the wet method. Furthermore, overheating intensity decreased by 54 % with the ventilated 20 mm air cavity compared to the reference, i.e., 23 percentage points higher than the wet method. Thus, the dry installation method has proven to be highly effective in enhancing the thermal performance of PCMFC cladding panels.

Study on the Hydration Heat Effect and Pipe Cooling System of a Mass Concrete Pile Cap

Under the action of cement hydration heat, the construction environment, thermal insulation measures, and pipe cooling systems, a mass concrete pile cap is subject to a complex internal temperature field, which makes it difficult to control its internal surface temperature difference (TISTD), the internal adiabatic temperature rise (TIATR), and the surface temperature (TST). In this study, a mass concrete pile cap of a very large bridge (the length, width, and height were 26.40 m, 20.90 m, and 5.00 m, respectively, and the central-pier pile cap was constructed with C40 concrete) was taken as the research object. The control factors affecting the temperature field of the pile cap were determined by comparing the field temperature measurements with the values calculated with finite element software simulation analysis. By using Midas Civil (2022 v1.2) and Midas FEA (NX 2022) finite element software, these factors (the concrete mold temperature, the concrete surface convection coefficient, the ambient temperature, the pipe cooling system parameters, etc.) were numerically analyzed, and their influence laws and degrees were determined.

Optimizing the indoor thermal environment and daylight performance of buildings with PCM glazing

With the development of energy efficient technologies for glass envelopes, using thermal storage techniques to improve their thermal inertia has become a trend in research. In the present study, the heat transfer and day-lighting models of a building with PCM glazing curtain wall (PGC) were developed. Multiple parameters such as glazing internal surface temperature, PCM liquid phase rate, indoor temperature, natural illumination, and daylighting coefficient were quantitatively analyzed to evaluate their indoor thermal environment and daylighting performance. The results show that the application of PGC can significantly improve indoor temperature uniformity and indoor thermal comfort compared to silica aerogel glass curtain wall (SGC) and hollow glass curtain wall (HGC). By filling 10 mm thick PCM, the temperature fluctuation of the inner surface of the glass and the midpoint temperature of the room can be reduced by 35 %, the peak temperature of the inner surface of the glass can be delayed by 0.89 h, and the average indoor natural light value and indoor daylight factor are satisfactory at 453.26 lx and 9.63 %, respectively. However, as the thickness of the PCM increases to 15 and 20 mm, the liquid fraction of the PCM and the energy storage performance of the PGC are greatly reduced, and natural daylighting does not meet the GB/t-50033-2013 limit.

The building application of foam concrete combined with PCM in cold regions and its energy efficiency

Building performance in cold regions greatly affects the quality of people living in the building. With the further development of the construction industry, how to improve the energy efficiency of buildings in cold regions has become one of the key issues. The study introduces paraffin phase change capsules as aggregate components on the basis of foam concrete, and then designs a matching energy efficiency analysis method to regulate the concrete parameters, and finally tests the performance of the research method and conducts an application analysis. The experimental results show that in performance simulation testing, the internal surface temperature decreases to 288.2 K at the minimum when the external temperature is 0°C to 4°C. It shows that the research method can effectively analyze the building performance, and the analysis method can optimize the performance of the foam concrete materials proposed in the research, and obtain building materials with better thermal insulation performance than the existing conventional materials. Research can provide certain technical references for building energy conservation in cold regions.

The Effects of Exterior Glazing on Human Thermal Comfort in Office Buildings

As a major component of the building envelope, the energy-saving design of exterior windows is key to energy savings in office buildings. The conventional design of exterior windows mainly focused on their impact on heating and cooling energy but ignored the indoor thermal comfort problems caused by the direct solar radiation transmitted by windows and the fluctuation of their internal surface temperatures. This study analyzed the influence of exterior windows on the indoor thermal environment of office buildings by carrying out field experiments. The experiments were carried out in a typical office building in Xi’an during December and January. The impact of exterior windows on human thermal comfort was studied from two perspectives: longwave radiation from the surface of window glass and solar shortwave radiation. It was found that solar radiation was the main cause of temperature fluctuations on the internal surface of windows and created non-uniform thermal environments. The mean radiant temperature fluctuations in the near-window area could reach up to 7.8 °C due to outdoor solar radiation in winter. Solar radiation transmitted by windows directly affects thermal sensations. Since conventional thermal comfort models or indices underestimated the thermal sensations of occupants in the presence of solar radiation, the additional thermal loads caused by solar radiation needed to be taken into account. The allowable operative temperature range for maintaining thermal comfort should be reduced by 0.5 °C when occupants are exposed to solar radiation.

Accurate state of temperature estimation for Lithium-Ion batteries based on square root cubature Kalman filter

Accurate state of temperature estimation for lithium-ion batteries is essential to ensure its safe and efficient operations. In this study, a state of temperature estimation framework for cylindrical lithium-ion batteries is proposed based on square root cubature Kalman filter algorithm, wherein the internal and surface temperatures of power battery are accurately estimated. Firstly, the electro-thermal coupling characteristics of lithium-ion battery is characterized based on an equivalent circuit model, Bernardi battery heat generation model and two-state lumped thermal model. On this basis, the discrete time-domain characteristics of internal and external temperature of the battery are addressed. Then, the genetic algorithm and forgetting factor recursive least squares algorithm are respectively employed to identify the circuit parameters and thermal physical parameters, and the internal and surface temperatures prediction is achieved based on square root cubature Kalman filter algorithm. The feasibility of the proposed temperature estimation method is verified at different charge and discharge process under wide range ambient temperature of -20 °C to 60 °C. The experimental results manifest that the proposed method can accurately online estimate the internal temperature and surface temperature with the mean absolute error of less than 1.16 °C.

Increase the internal surface temperature to eliminate surface condensation on the window

One of the most critical places in buildings in terms of physical thermal properties are windows. This is the most frequent place where the temperature drops below the dew point and surface condensation, or mould, develops. The work deals with the study of the surface temperature courses at the critical points of window glazing and connection joints and the subsequent improvement of the initial unsatisfactory condition by using a patented technology, a conductive material without further intervention in the structure. In the case of a very unsatisfactory condition, a heating resistance wire was attached to the bar, which in combination with the bar distributes the heat to a wider area. The evaluation of the surface temperature increase was performed in a steady-state thermal analysis with fixed boundary conditions and then with the influence of the flow in a room with the heater placed under the window.

Development of lumped-parameters models for the thermal evaluation and air quality in aircrafts

Aircraft cabins are a challenging category when dealing with thermal comfort and air quality inside means of transport. Two simplified dynamic models are developed. The first one is a lumped resistance-capacitance model for assessing the cabin thermal behaviour during the cruise phase. The fuselage is discretised into several slices and each one is represented through an RC network consisting of eleven nodes, thirteen resistances and three capacities. A thermal balance equation is set for each node and the linear system is solved to calculate the air and surfaces’ temperatures. The model is validated by comparison with literature experimental data from ten flights, showing that the predicted temperatures agree well with the measured ones, presenting an RMSE of 1.5, 1.9 and 1.3 °C for cabin air, floor and cabin internal surface temperatures, respectively. A sensitivity analysis is conducted, for which the internal air temperature increases linearly with occupancy rate and decreases with cruising altitude. Secondly, an air quality model is proposed to evaluate the presence of pollutants inside the cabin, based on a simple concentration balance equation. Ventilation flow rates recommended from standards and a recirculation rate below 50-60% should be set to maintain acceptable CO2 levels.

Thermal storage performance analysis of building envelope based on big data sensor network

In order to understand the thermal storage performance analysis of building envelope, the author proposes a research on thermal storage performance analysis of building envelope based on Big data sensor network. The author first compares and analyzes the thermal storage performance parameter systems of different theoretical methods, and determines the key characterization parameters of thermal storage performance under different working conditions based on the analysis of the thermal storage process. Second, in order to compare and verify the measured and simulated indoor temperature of the building, two groups of buildings with identical exterior wall insulation performance and distinct thermal storage performance were chosen. Three distinct thermal storage levels of the building?s exterior walls were used to simulate and analyze the internal surface temperature, heat flux density, and building cooling and heating load. Summer night ventilation was used to investigate the effect of ventilation volume on building cooling loads. In the end, a provincial office building was chosen as the research subject. The structure comprises of two stories, one underground and two over the ground, with a north hub point of 180?. The investigation object is a two-story room. The trial results demonstrate that the deliberate outcomes are in great concurrence with the mimicked results. For the district of the region, under a similar protection execution of the nook structure, the inner surface temperature of the weighty construction outside wall is higher in winter, lower in summer, with a higher intensity load in winter and a lower cooling load in summer. The proper air changes each hour of building night ventilation is 16 ach, and the effect on the cooling heap of weighty structures is huge. Demonstrated the precision of the reproduction technique and model.

Improving indoor environmental quality in an affordable house by using a vegetated wall: A case study in subtropical Brazil

Indoor environmental quality of buildings, including thermal, acoustic, visual comfort, and air quality, directly impacts the comfort, health, and productivity of occupants. However, in Brazil, the high deficit of affordable housing units has led to a situation where environmental quality is often overlooked in favour of low investment costs, prioritizing quantity over quality. Furthermore, the poorest segments of the population, who rely on affordable housing, are disproportionately affected by energy costs. Therefore, it is crucial to conduct research on low-cost energy solutions for social housing to improve the sustainability of people's lives. In this light, a study was conducted to monitor the energy performance of a vegetated wall made of deciduous species and compare it to a bare wall used in an affordable house in subtropical Brazil. Parameters, such as internal and external surface temperatures, nearby microclimatic conditions, and heat transfer through the vegetated and bare walls, were monitored every 5 min over a two-year period. The heat flux analysis revealed that the vegetated wall reduced conductive heat up to 83 % during summer days, significantly lowering the external surface temperature by 8.6 °C due to the presence of the plant layer. Moreover, the vegetated wall generally exhibited lower shortwave and longwave radiative and convective heat fluxes. These findings contribute to our understanding of energy transfer through vegetated walls in subtropical Brazil, including the impact of adjacent microclimatic conditions. Furthermore, the results confirm the potential of vegetated walls to effectively reduce cooling and heating demands at a minimal additional cost.

Investigation on the Through-Thickness Temperature Gradient and Thermal Stress of Concrete Box Girders

Bridges are generally affected by thermal loads which include the daily cycle, seasonal cycle and annual cycle. Thermal loads mode and thermal effects on bridges, especially for concrete girders, are quite essential but complicated. To investigate the temperature field and thermal stress in the thickness direction of a concrete box girder, the temperature field of a prestressed concrete continuous box girder bridge is monitored, and the temperature distribution in the thickness direction of the concrete box girder is analyzed. Finite element simulation, utilizing air elements specifically designed for concrete box girders, is employed to analyze the temperature field and thermal stress profiles along the thickness of the slab. The findings indicate a variation in temperature along the thickness of the concrete box girder slab. The most significant temperature differential, reaching up to 10.7 °C, is observed along the thickness of the top slab, followed by the bottom plate, with the web exhibiting relatively smaller differentials. Temperature in the full thickness range has a significant impact on the top plate, while the web plate and bottom plate are greatly influenced by temperature ranging from the outer surface to the center of the plate thickness. The temperature difference between the center of the plate thickness and the inner surface is approximately 0. The variation in temperature due to the variation in thickness direction is a temporal factor, wherein the outer layer of the roof is primarily compressed, while the inner layer is subjected to tension. The external surface of the web is mainly compressed. The stress exerted by the internal surface temperature is minimal. The internal and external surface effects of the floor are similar, and as time passes, tensile and compressive stresses appear.

Novel composite materials with high near-infrared reflectance properties to retard the thermal aging of polyethylene: Pr3+ and Er3+ doped La2Zr2O7 compounds

In this paper, Er3+ and Pr3+ successfully replaced La3+ in the lattice without changing the structure of La2Zr2O7 pyrochlore, and finally formed the substituted solid solution La2-xMxZr2O7+δ (M = Er, Pr; x = 0–0.25). SEM analysis shows that the pigments were in the shape of nearly spherical particles with a particle size between 10 and 60 nm. La2-xPrxZr2O7+δ and La2-xErxZr2O7 materials have high NIR reflectance properties, with the NIR reflectance of 68.46%–92.51% and 82.79%–90.89%, which are related to the variation of free carrier concentration due to doping content. Compared with pure polyethylene material, the polyethylene plastic samples containing La2-xPrxZr2O7+δ and La2-xErxZr2O7+δ not only had lower internal surface temperatures, 5.9–11.4 °C and 6.9–13.2 °C lower but also had significantly lower thermal aging. In conclusion, the use of synthetic pigments with high NIR reflectivity as additives can delay the thermal aging of plastics and increase the aging resilience of plastic.

Experimental analysis of temperature and vapor core pressure for an annular heat pipe

The main contribution of this study is the effects of the operating conditions on the internal vapor pressure and temperature in an annular screen wick heat pipe, using distilled water as the working fluid. High-resolution pressure transducers, optical fiber distributed temperature sensors, and K-type thermocouples were employed to measure the internal and external temperatures as well as the local static pressures at different axial positions of the heat pipe. Temporal and frequency analysis using a one-dimensional continuous wavelet transform was performed on the differential pressure data to characterize flow behavior and infer the flow regime occurring within the heat pipe. The heat pipe was tested in multiple orientations with respect to the horizon (θ=0°, 45°, and 90°), heat loads (25, 50, and 75 W), and condenser coolant temperatures (Tw,in= 10 °C, 20 °C, and 30 °C). To estimate the vapor-phase flow friction factor for multiple Reynolds numbers, the Lockhart–Martinelli correlation was employed. This study provides critical experimental data and analyses for complex two-phase flow behavior in an annular wick heat pipe geometry. The thermal resistance and effective thermal conductivity were estimated as a function of the heat pipe orientation and power input. The experimental investigation revealed that power input and orientation influence both the internal vapor core and external surface temperatures, as well as the local pressure response. The outcomes from this study provide a valuable database that supports the advancement of heat pipe design, modeling, and validation.

Evaluation of the cooling potential of a vertical greenery system coupled to a building through an experimentally validated transient model

Despite several studies showed that Vertical Greenery Systems (VGSs) have relevant thermal benefits at urban and building scales, researches devoted to investigate the benefits of a green facade through detailed transient thermal simulations are scarce. Furthermore, a study comparing the effectiveness of different plant types is still missing. The present paper aims to fill such gaps by studying the effectiveness of a green façade to improve the thermal behaviour of a well-insulated lightweight building in the Mediterranean area, as well as the perceived indoor thermal conditions, based on both on-site experimental measurements and dynamic thermal simulations with a novel Type in TRNSYS validated through the monitoring campaign. To this aim, two identical full-scale prefabricated modules were installed and monitored at the University Campus of Catania (Italy), differing from each other because one of them hosted a climbing plant species in its west façade. The validated numerical model was then used to appraise the cooling effect of the green façade with two different plant species commonly used in Mediterranean countries (Trachelospermum Jasminoides and Hedera Helix namely). Results show that Hedera helix ensures the best performance when the foliage layer is at an intermediate state of its growing process, while under full foliage development the species investigated show almost the same performance. The incoming heat flux can be strongly attenuated, showing a quite flat daily profile, while the peak value of the internal and external surface temperature of the wall can be reduced by up to 1.6 °C and 10.5 °C, respectively.

Optimization and operation control for the combined impinging jet ventilation and chilled ceiling system with different cooling loads

The matching relationship of operating parameters between the air supply and radiant systems has significant impact on the indoor thermal comfort and energy efficiency for combined air-conditioning system. The impinging jet ventilation (IJV) and chilled ceiling (CC) combined system (IJV/CC) overcomes the drawback of IJV which cannot be used in spaces with high cooling load. However, the matching relationship between the operating parameters of the IJV and CC are not clear due to limited research on IJV/CC at present. To ensure good thermal comfort and indoor air quality of the IJV/CC in an energy efficient way, this study mainly focuses on exploring the optimal combination of the operating parameters between the IJV and CC (including the supply temperature and supply velocity of IJV and internal surface temperature of CC (Tc)). First, the indoor thermal environment for IJV/CC operating with different combinations of design parameters is simulated by CFD. Second, response surface methodology (RSM) is utilized to establish predictive models for various ventilation performance indicators by collecting the simulation results. Then, the optimal combinations of operating parameters between the IJV and CC are determined by using the technique of order preference by similarity to ideal solution (TOPSIS) coupled with the developed RSM models. Finally, control strategies for the IJV and CC are discussed and it suggests setting the value of Tc in the range of 20–21 °C and a variable air volume system is preferred for the control of the air supply system to achieve efficient operation of IJV/CC.