scholarly journals n-Octadecane/Fumed Silica Phase Change Composite as Building Envelope for High Energy Efficiency

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 566
Author(s):  
Giang Tien Nguyen ◽  
Ha Soo Hwang ◽  
Jiyoung Lee ◽  
Dong An Cha ◽  
In Park
Keyword(s):  
Energy Efficiency ◽  
Phase Change ◽  
Fumed Silica ◽  
High Energy ◽  
Building Envelope ◽  
Composite Panel ◽  
Halogen Lamp ◽  
High Porosity ◽  
Latent Heat Storage ◽  
Silica Phase

A novel n-octadecane/fumed silica phase change composite has been prepared as a building envelope with a high content of phase change material and improved energy efficiency. With a high porosity (88 vol%), the fumed silica provided sufficient space to impregnate a high quantity of n-octadecane (70 wt%). The composite exhibited high latent heat storage capacity (155.8 J/g), high crystallization fraction (96.5%), and a melting temperature of 26.76 °C close to that of pure n-octadecane. A 200 accelerated thermal cycle test confirmed good thermal reliability and chemical stability of the phase change composite. The thermal conductivity of n-octadecane was reduced by 34% after impregnation in fumed silica. A phase change composite panel was fabricated and compared to a commercial polystyrene foam panel. When used as the roof of a test room, the phase change composite panel more efficiently retarded heat transfer from a halogen lamp to the room and delayed the increase in the indoor temperature than that by the polystyrene panel. The indoor temperatures of the room with the phase change composite panel roof were 19.8 and 22.9 °C, while those with the polystyrene panel roof were 29.9 and 31.9 °C at 2200 and 9000 s after lamp illumination.

scholarly journals Numerical Simulation of Phase Change Material Composite Wallboard in a Multi-Layered Building Envelope

2012 ◽  
Author(s):  
Stephen D. Zwanzig ◽  
Yongsheng Lian ◽  
Ellen G. Brehob
Keyword(s):  
Energy Consumption ◽  
Boundary Conditions ◽  
Phase Change ◽  
Latent Heat ◽  
Residential Buildings ◽  
Peak Load ◽  
The United States ◽  
Building Envelope ◽  
Latent Heat Storage ◽  
Exterior Boundary

Residential buildings account for a large portion of total energy consumption in the United States. Residential energy usage can be dramatically reduced by improving the efficiency of building envelope systems. One such method is to incorporate thermally massive construction materials into the building envelope. This benefits building operation by reducing the energy requirement for maintaining thermal comfort, downsizing the AC/heating equipment, and shifting the peak load from the electrical grid. When impregnated or encapsulated into wallboard or concrete systems, phase change materials (PCMs) can greatly enhance their thermal energy storage capacity and effective thermal mass. In this work we numerically study the potential of PCM on energy saving for residential homes. For that purpose we solve the one-dimensional, transient heat equation through the multi-layered building envelope using the Crank-Nicolson discretization scheme. The latent heat storage of the PCM was accounted for with a phase fraction in a latent heat source term. Using this code we examine a PCM composite wallboard incorporated into the walls and roof of a typical residential building across various climate zones. The PCM performance was studied under all seasonal conditions using the latest typical meteorological year (TMY3) data for exterior boundary conditions. Comparisons were made between different PCM wallboard locations. Our work shows that there is an optimized location for PCM placement within building envelope surfaces dependent upon the resistance values between the PCM layer and the exterior boundary conditions. We further identified the energy savings potential by comparing the performance of the PCM wallboard against the performance of a building envelope without PCM. Our study shows that PCM composite wallboard can reduce the energy consumption in summer and winter and can shift the peak electricity load in the summer.

scholarly journals Glass Curtain Wall Technology and Sustainability in Commercial Buildings in Auckland, New Zealand

2020 ◽  
Vol 7 (2) ◽  
pp. 57-65
Author(s):  
Yi Wu ◽  
Claire Flemmer
Keyword(s):  
Energy Efficiency ◽  
New Zealand ◽  
Thermal Comfort ◽  
Environmental Sustainability ◽  
High Energy ◽  
Building Envelope ◽  
Commercial Buildings ◽  
Continuous Heating ◽  
Curtain Wall ◽  
Glass Curtain Wall

Glass curtain wall provides an attractive building envelope, but it is generally regarded as unsustainable because of the high energy needed to maintain thermal comfort. This research explores the advances in the technology of glass cladding and the complex issues associated with judging its sustainability. It assesses the technology and sustainability of glass curtain wall on a sample of thirty commercial buildings in Auckland, New Zealand. Field observations of the glass-clad buildings, coupled with surveys of the building occupants and of glass cladding professionals are used to investigate the cladding characteristics, operational performance, sustainability aspects and future trends. The majority of the sample buildings are low-rise office buildings. The occupants like the aesthetics and indoor environment quality of their glass-clad buildings. However, continuous heating, ventilation and air conditioning are needed in order to maintain thermal comfort within the buildings and this has high energy consumption. The increasing use of unitized systems with double glazing instead of stick-built systems with single glazing improves the sustainability of the cladding through less material wastage and better energy efficiency. Inclusion of photovoltaic modules in the curtain wall also improves energy efficiency but it is currently too expensive for use in New Zealand. Environmental sustainability is also improved when factors such as climate, the orientation of glazed façades, solar control, ventilation and the interior building layout are considered. Any assessment of glass curtain wall sustainability needs to consider the economic and social aspects as well as the environmental aspects such as energy use

Unscrambling the Building Envelope Insulation Technique in "Tianjin Energy Efficiency Design Standard for Rural Residential Buildings"

2013 ◽  
Vol 805-806 ◽  
pp. 1519-1523 ◽  
Author(s):  
Chang Feng Wang ◽  
Guo Qiang Fan
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Residential Buildings ◽  
Minimum Energy ◽  
High Energy ◽  
Building Envelope ◽  
Minimum Energy Consumption ◽  
Tianjin City ◽  
Energy Efficiency Standard ◽  
Energy Efficiency Standards

In order to solve problems of high energy consumption and poor indoor thermal comfort in existing rural residential buildings, Tianjin city developed Tianjin energy efficiency standard for rural residential buildings, the building envelope insulation technique in the standard-including determination of heat transfer coefficient, principle of choosing insulation materials for building envelope, energy efficiency standards of walls, windows, and roofs are unscrambled particularly in this paper. It is suggested that natural materials and appropriate techniques are used to achieve the energy-saving goal for rural residential buildings with minimum energy consumption.

scholarly journals Evaluating the potential energy savings of residential buildings and utilizing solar energy in the middle region of Saudi Arabia – Case study

2020 ◽  
pp. 014459872097514
Author(s):  
AbdulRahman S Almushaikah ◽  
Radwan A Almasri
Keyword(s):  
Energy Efficiency ◽  
Saudi Arabia ◽  
Energy Consumption ◽  
Solar Energy ◽  
Residential Buildings ◽  
Energy Performance ◽  
High Energy ◽  
Building Envelope ◽  
Economic Feasibility ◽  
Middle Region

Lately, with the growth in energy consumption worldwide to support global efforts to improve the climate, developing nations have to take significant measures. Kingdom of Saudi Arabia (KSA) implemented meaningful policy actions towards promoting energy efficiency (EE) in several sectors, especially in the building sector, to be more sustainable. In this paper, various EE measures and solar energy prospects are investigated for the residential sector, in two locations in the middle region of the KSA. An energy performance analysis of pre-existing residential buildings with an overall design is performed using simulation programs. However, installing EE measures in the building envelope is important to achieve an efficient sector regarding its energy consumption. The findings showed that applying EE measures for the building envelope, walls, roof, and windows should be considered first that makes the energy conservation possible. In Riyadh, EE measures are responsible for reducing energy consumption by 27% for walls, 14% for roof, and 6% for window, and by 29%, 13%, and 6% for walls, roof, and windows, respectively, for Qassim. However, the most impactful EE solution was selecting a heating, ventilation, and air conditioning (HVAC) system with a high energy efficiency rate (EER), which can minimize the energy consumption by 33% and 32% for Riyadh and Qassim, respectively. The study's feasibility showed that the number of years needed to offset the initial investment for a proposed roof PV system exceeds the project's life, if the energy produced is exported to the grid at the official export tariff of 0.019 $/kWh. However, the simple payback time was 13.42 years if the energy produced is exported to the grid at a rate of 0.048 $/kWh, reflecting the project's economic feasibility.

scholarly journals Comparative analysis of radon concentrations in buildings of different energy efficiency classes on example of five Russian cities

2020 ◽  
Vol 13 (2) ◽  
pp. 47-56
Author(s):  
I. V. Yarmoshenko ◽  
A. D. Onishchenko ◽  
G. P. Malinovsky ◽  
A. V. Vasilyev ◽  
E. I. Nazarov ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Comparative Analysis ◽  
Radon Concentration ◽  
Energy Efficient ◽  
Residential Buildings ◽  
High Energy ◽  
Building Envelope ◽  
Soviet Period ◽  
Energy Efficient Buildings ◽  
Radon Concentrations

A comparative analysis of the radon concentrations in modern multi-storey residential buildings of high energy efficiency class and buildings typical for urban areas of the twentieth century was carried out. The study was conducted in Russian cities located in various climatic zones – Ekaterinburg, Krasnodar, St. Petersburg, Salekhard, Chelyabinsk. The radon concentration in samples of buildings was measured using integrated radon radiometers based on nuclear track detectors according to a single method. The surveyed sample included 498 apartments in multi-apartment buildings. Among all the examined building types, the highest average radon concentration is observed in modern energy-efficient houses – 43 Bq/m3. In other types of buildings, the following average radon concentrations were obtained: brick 2–5 floors – 35 Bq/m3; panel 5 floors – 32 Bq/m3; panel 7–12 floors 1970-1990 years of construction – 22 Bq/m3; brick> 5 floors 1970–1980 years of construction – 20 Bq m3; panel, built since 1990 – 24 Bq/m3. The results of the study confirm the assumption that radon concentration in modern multi-storey energy-efficient houses is on average higher than in typical residential buildings of the Soviet period. The increased accumulation of radon in energy-efficient buildings is associated with a decrease in the building envelope permeability and the contribution of fresh air to the general air exchange. Despite the fact that there were no cases of exceeding hygienic standards for the indoor radon concentration in the framework of this study, the higher radon concentration in buildings of increased energy efficiency requires attention from the point of view of implementing the principle of optimization of radiation protection. In the future, extensive construction of energy-efficient buildings may increase the average and collective doses to the urban population in the Russian Federation.

scholarly journals Triglycerides as Novel Phase-Change Materials: A Review and Assessment of Their Thermal Properties

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5572
Author(s):  
Rebecca Ravotti ◽  
Jörg Worlitschek ◽  
Colin R. Pulham ◽  
Anastasia Stamatiou
Keyword(s):  
Thermal Properties ◽  
Phase Change ◽  
Phase Change Materials ◽  
Waste Heat ◽  
High Energy ◽  
High Energy Density ◽  
Melting Points ◽  
Latent Heat Storage ◽  
Chemical Structures ◽  
Energy Technologies

Latent Heat Storage (LHS) with Phase-Change Materials (PCMs) represents a high energy density storage technology which could be applied in a variety of applications such as waste heat recovery and integration of renewable energy technologies in energy systems. To increase the sustainability of these storage solutions, PCMs have to be developed with particular regard to bio-origin and biodegradability. Triglycerides represent an interesting class of esters as the main constituents of animal and vegetable fats, with attractive thermal properties. In order to be used as PCMs, the thermal behaviour of triglycerides has to be fully understood, as in some cases they have been reported to show polymorphism and supercooling. This study assesses the suitability of triglycerides as PCMs by reviewing the literature published so far on their behaviour and properties. In particular, melting points, enthalpies of fusion, polymorphism, thermal conductivities, heat capacities and thermal cycling stabilities are considered, with a focus on LHS and thermal energy storage applications. In addition, the efforts conducted regarding modelling and the prediction of melting points and enthalpies based on chemical structures are summarized and assessed.

scholarly journals Solvothermal method as a green chemistry solution for micro-encapsulation of phase change materials for high temperature thermal energy storage

2018 ◽  
Vol 5 ◽  
pp. 4 ◽  
Author(s):  
Albert Ioan Tudor ◽  
Adrian Mihail Motoc ◽  
Cristina Florentina Ciobota ◽  
Dan. Nastase Ciobota ◽  
Radu Robert Piticescu ◽  
...  
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Solvothermal Method ◽  
High Energy ◽  
High Energy Density ◽  
Latent Heat Storage

Thermal energy storage systems using phase change materials (PCMs) as latent heat storage are one of the main challenges at European level in improving the performances and efficiency of concentrated solar power energy generation due to their high energy density. PCM with high working temperatures in the temperature range 300–500 °C are required for these purposes. However their use is still limited due to the problems raised by the corrosion of the majority of high temperature PCMs and lower thermal transfer properties. Micro-encapsulation was proposed as one method to overcome these problems. Different micro-encapsulation methods proposed in the literature are presented and discussed. An original process for the micro-encapsulation of potassium nitrate as PCM in inorganic zinc oxide shells based on a solvothermal method followed by spray drying to produce microcapsules with controlled phase composition and distribution is proposed and their transformation temperatures and enthalpies measured by differential scanning calorimetry are presented.

scholarly journals Numerical Analysis of Building Envelope with Movable Phase Change Materials for Heating Applications

2019 ◽  
Vol 9 (18) ◽  
pp. 3688
Author(s):  
Alvaro de Gracia
Keyword(s):  
Numerical Analysis ◽  
Phase Change ◽  
Phase Change Materials ◽  
Building Envelope ◽  
Space Heating ◽  
Passive Heating ◽  
Latent Heat Storage ◽  
Heating And Cooling ◽  
Design Variables ◽  
Heat Storage Materials

Latent heat storage materials have been tested by several researchers for decades to be used as passive heating and cooling systems in buildings but their implementation into building components is still stacked as is facing specific technical limitations related to difficulties to be charged both in heating and cooling periods. This paper presents a numerical analysis to evaluate the potential of a disruptive system, which is designed to solve the main drawbacks and to convert phase change materials (PCM) passive heating technology into a competitive solution for the building sector. The novel technology moves PCM layer with respect to the insulation layer inside the building component to maximize solar benefits in winter and be able to actively provide space heating. Design variables such as PCM melting point and control schemes were optimized. The results demonstrated that this technology is not only able to limit heat losses towards outdoors but it can provide space heating from stored solar energy when required. The promising numerical results endorse the possibility to build a future experimental prototype to quantify more in detail the benefits of this system.

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