Effect of water-ice phase change on thermal performance of building materials

2016 ◽  
Author(s):  
Václav Kočí ◽  
Robert Černý
Keyword(s):  
Phase Change ◽  
Thermal Performance ◽  
Building Materials ◽  
Water Ice ◽  
Effect Of Water ◽  
Ice Phase

Quantitative stability analyses of multiwall carbon nanotube nanofluids following water/ice phase change cycling

2016 ◽  
Vol 28 (5) ◽  
pp. 055702 ◽  
Author(s):  
Jason Ivall ◽  
Gabriel Langlois-Rahme ◽  
Sylvain Coulombe ◽  
Phillip Servio
Keyword(s):  
Carbon Nanotube ◽  
Phase Change ◽  
Multiwall Carbon Nanotube ◽  
Quantitative Stability ◽  
Water Ice ◽  
Stability Analyses ◽  
Multiwall Carbon ◽  
Ice Phase

Investigation of microscopic mechanisms for water-ice phase change propagation control

2022 ◽  
Vol 184 ◽  
pp. 122357
Author(s):  
Yu-Kai Weng ◽  
Seungha Shin ◽  
Kenneth D. Kihm ◽  
Mohammad Bahzad ◽  
Douglas S. Aaron
Keyword(s):  
Phase Change ◽  
Change Propagation ◽  
Water Ice ◽  
Ice Phase

scholarly journals Study on Mechanical Properties and Energy Dissipation of Frozen Sandstone under Shock Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Lei Wang ◽  
Yue Qin ◽  
Haibin Jia ◽  
Hongming Su ◽  
Shiguan Chen
Keyword(s):  
Mechanical Properties ◽  
Energy Dissipation ◽  
Phase Change ◽  
Strain Rate ◽  
Impact Loading ◽  
Strengthening Effect ◽  
Red Sandstone ◽  
Water Ice ◽  
The Difference ◽  
Ice Phase

In order to understand the mechanical properties and energy dissipation law of frozen sandstone under impact loading, the cretaceous water-rich red sandstone was selected as the research object to conduct impact tests at different freezing temperatures (0°C, −10°C, −20°C, and −30°C). The test results suggested the following: (1) the peak stress and peak strain of frozen sandstone are positively correlated with strain rate and freezing temperature, and the strain rate strengthening effect and the low-temperature hardening effect are obvious. (2) The strain rate sensitivity of dynamic stress increase factor (DIF) is negatively correlated with temperature. Water-ice phase change and the difference in the cold shrinkage rate of rock matrix under strong impact loading will degrade the performance of rock together, so DIF is less than 1. (3) In the negative temperature range from −10°C to −30°C, DEIF is always greater than 1. The energy dissipation rate of red sandstone specimens fluctuated between 10% and 25% under the impact loading, and the data are discrete, showing obvious strain rate independence. The failure form changes from tensile failure to shear and particle crushing failure. (4) Combined with the micromechanism analysis, the difference in dynamic mechanical properties of red sandstone at different temperatures is caused by the water-ice phase change and the different cold shrinkage rates of the frozen rock medium. When the temperature drops from 0°C to −2°C, water migrates to the free space of the pore of frozen rock and freezes into ice crystal, resulting in frozen shrinkage. At −30°C, the expansion of ice dominates and the migration of water will stop, leading to frost heave.

scholarly journals Thermal Performance Measurement Procedure and Its Accuracy for Shape-Stabilized Phase-Change Material and Microcapsule Phase-Change Material Combined with Building Materials

2021 ◽  
Vol 13 (12) ◽  
pp. 6671
Author(s):  
Hyun Bae Kim ◽  
Masayuki Mae ◽  
Youngjin Choi
Keyword(s):  
Phase Change ◽  
Specific Heat ◽  
Phase Change Material ◽  
Thermal Performance ◽  
Building Materials ◽  
Dynamic Method ◽  
Setting Time ◽  
Peak Temperature ◽  
Scanning Calorimetry ◽  
Change Material

The accuracy of differential scanning calorimetry (DSC) used in the dynamic method, which is the method most widely used to measure the thermal performance of existing phase-change materials (PCMs), is limited when measuring the phase-change range and peak temperature of PCMs combined with building materials. Therefore, we measured the thermal performance in a thermochamber; the samples were a sheet of shape-stabilized phase-change material (SSPCM) and a microencapsulated PCM-impregnated gypsum board fabricated by combining PCM building materials with paraffin. Then, we investigated ways to improve the measurement accuracy. We confirmed the setting time of the thermochamber temperature change based on the internal temperature of the PCM and the effect of the PCM capacity on its thermal performance using the dynamic method. The temperature was increased or decreased in uniform steps at regular time intervals. The error of the heat absorption and release was less than 2% when a stabilization time of at least 4 h elapsed before the start of the heating or cooling process. Overall trends in the specific heat and enthalpy, such as the phase-change section and peak temperature of the PCM, were similar regardless of the setting time. Thus, it was confirmed that the latent heat performance did not increase proportionally with the increase in the PCM capacity. The proposed approach can be used to measure the specific heat and enthalpy of various types of PCMs and building materials.

A novel simple practical thermal-hydraulic-mechanical (THM) coupling model with water-ice phase change

2020 ◽  
Vol 118 ◽  
pp. 103357 ◽  
Author(s):  
Guofeng Li ◽  
Ning Li ◽  
Yue Bai ◽  
Naifei Liu ◽  
Mingming He ◽  
...  
Keyword(s):  
Phase Change ◽  
Coupling Model ◽  
Water Ice ◽  
Ice Phase

scholarly journals Numerical assessment of brick walls` use incorporating a phase change material towards thermal performance in buildings during a passive cooling strategy

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 1909-1922
Author(s):  
Zohir Younsi ◽  
Hassan Naji
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Thermal Performance ◽  
Building Materials ◽  
Performance Enhancement ◽  
Numerical Approach ◽  
Building Envelope ◽  
Passive Cooling ◽  
Volume Method ◽  
Change Material

The integration of new building materials incorporating phase change material (PCM) into the building envelope leads to an increase of the heat storage capacity, which may have an influence on minimizing the cooling demand and heating of the building. This work addresses a thermal performance enhancement of brick walls with incorporated PCM. The improvement has been assessed through a numerical approach in dealing with a 1-D transient conduction problem with phase change, while leaning on experimental results from a transient guarded hot plates method. The simulations have been fulfilled using a hybrid method combining both the finite volume method and an enthalpy porosity technique. The results of this combined approach are in good agreement. In the light of the findings obtained, it appears that PCM incorporation into a brick masonry can both reduce peak temperatures up to 3?C and smooth out daily fluctuations. Thereby, the evaluation achieved can turns out useful in developing brick walls with an incorporated PCM for passive cooling, thus improving buildings thermal performance.

scholarly journals Using Latent Energy of Water-ice Phase Change to Reduce Energy Losses in Buildings in Cold Climate

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Energy Efficiency ◽  
Phase Change ◽  
Building Energy ◽  
Building Envelope ◽  
Cold Climate ◽  
Building Energy Efficiency ◽  
Water Ice ◽  
Latent Energy ◽  
Eu Directive ◽  
Ice Phase

Energy efficiency in buildings is a very important challenge that has to be faced in order to achieve the aims set by the new EU directive on Building energy efficiency encouraging nearly zero energy buildings. Unfortunately in countries with cold climate it is very hard to achieve this goal. The thickness of insulation needed to reach low energy consumption in cold climate is very big and in many cases it is not economically feasible. There is a need for new solutions for increasing building energy efficiency. In this paper a new solution for increasing building energy efficiency is proposed. It is proposed to use the latent energy of water-ice phase change to reduce heat conduction losses through building envelope. The latent energy is recovered by using low potential heat source. In this paper the validity of the proposed new solution is tested on a one dimensional scale – homogeneous infinite wall. The presented methodology is chosen to calculate systems operational efficiency throughout the whole year.

scholarly journals Analysing the Effect of Substrate Properties on Building Envelope Thermal Performance in Various Climates

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5119
Author(s):  
Kishor T. Zingre ◽  
Kiran Kumar D. E. V. S. ◽  
Man Pun Wan
Keyword(s):  
Solar Radiation ◽  
Thermal Resistance ◽  
Phase Change ◽  
Thermal Performance ◽  
Building Materials ◽  
Field Experiments ◽  
Building Envelope ◽  
Surface Solar Radiation ◽  
Heat Gain ◽  
Radiation Properties

Existing regulations on the thermal efficiency of building envelope assemblies are based on the steady state thermal properties of substrate materials. Heat transfer mechanisms of passive heat curbing methods such as phase change materials and cool materials, which are dynamic in nature, are currently not being accounted for. The effectiveness of thermo-physical and solar radiation properties of building materials (i.e., solid homogeneous layers without air gap) in reducing the heat gain into a building in a hot climate could be well understood with the equivalent thermal resistance (Req) concept. A simple and easy-to-use mathematical derivation (i.e., to estimate the instantaneous heat flux across an envelope assembly) is proposed in this paper to understand the mechanism of equivalent R-value (i.e., reciprocal of thermal transmittance, U-value) due to solar radiation properties of passive substrate materials. The model is validated against field experiments carried out at two apartment units of a residential building. The Req due to high outer surface solar radiation properties (i.e., by applying a cool coating) is dynamic as it varies with the weather conditions. The effect of a substrate material’s solar radiation and thermo-physical properties on the overall roof thermal performance is investigated using the Req model for four cooling dominated climates around the globe, having different diurnal conditions and sky temperatures. Increasing the outer surface’s solar reflectance (from 10% to 80%) reduces net heat gain through the flat roof during both daytime and nighttime. In contrast, adding only thermal resistance (from 5 mm to 75 mm thick polyurethane) or volumetric heat capacity (by adding 5 mm thick phase change material) to the building envelope brings down heat gain during the day, but not in the night. Thermal insulation is found to be the second effective property, followed by thermal mass irrespective of different diurnal conditions and sky temperatures across the climates.

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