scholarly journals Evaluation of the Thermal Comfort and Energy Demand in a Building with Rammed Earth Walls in Spain: Influence of the Use of In Situ Measured Thermal Conductivity and Estimated Values

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 635
Author(s):  
Miguel Ángel Mellado Mascaraque ◽  
Francisco Javier Castilla Pascual ◽  
Víctor Pérez Andreu ◽  
Guillermo Adrián Gosalbo Guenot

This paper describes the influence of thermal parameters—conductivity, transmittance, and thermal mass—in the estimation of comfort and energy demand of a building with rammed earth walls, and consequently, the compliance with standards. It is known that nominal design data does not match in situ measured values, especially in traditionally constructed buildings. We have therefore monitored a room in a building with rammed earth walls, designed a computerised model, and compared four different alternatives where we have changed the value for the thermal conductivity (in situ vs. estimated) and the consideration of thermal mass. When we then analyse the compliance with the Spanish energy saving code, using measured values would result in lower differences with the standards’ limits and even comply with the global thermal transmittance (K-value) requirement. This would mean a more realistic approach to the restoration of traditional buildings leading to the use of thinner and more suitable insulation and retrofitting systems, encouraging the use of rammed earth in new buildings, and therefore reducing the carbon footprint due to materials used in construction. Results show that the building model that uses in situ values and considers thermal mass (S1) is closer to reality when assessing thermal comfort. Finally, using nominal data would result in requiring 43% more energy in the selected winter period and 102% more energy in the selected summer period to keep the same comfort conditions as in the alternative where measured values are used.

2018 ◽  
Vol 22 (Suppl. 4) ◽  
pp. 1143-1155
Author(s):  
Vesna Lovec ◽  
Milica Jovanovic-Popovic ◽  
Branislav Zivkovic

The conducted research examines the thermal behaviour of the rammed earth walls, which is the basic structural and fa?ade element of traditional Vojvodina house. The traditional rammed earth house represents an important part of the total building stock of Vojvodina. Earth is a locally available, cheap, natural, environmentally friendly building material and has been used extensively for traditional family houses in Vojvodina. It has ecological and ?green? characteristics, which can be assessed as very high quality, and they are of significant importance in the context of sustainable development and striving to reduce energy consumption today. The research examines thermal behaviour of rammed earth wall, including theoretical analysis of: the heat transfer coefficient, U, the thermal resistance, R, and thermal conductivity, ?. One of the basic elements of thermal behaviour, the thermal mass, has been analyzed both theoretically and by measuring in situ. The in situ measurements were conducted on the traditional house in Vojvodina by measuring inside and outside surface wall and air temperature in summer. Analyses of rammed earth wall thermal performances have shown that the wall has low thermal conductivity, high heat capacity and significant thermal mass effect which is the key element enabling thermal stability. The research indicates rather good thermal properties of the rammed earth walls. Potential of rammed earth wall in Vojvodina should be an issue of further analysis, although the possibility of improvement of existing facilities to meet current standards in terms of energy efficiency should be considered.


Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 325
Author(s):  
Giada Giuffrida ◽  
Maurizio Detommaso ◽  
Francesco Nocera ◽  
Rosa Caponetto

The renewed attention paid to raw earth construction in recent decades is linked to its undoubted sustainability, cost-effectiveness, and low embodied energy. In Italy, the use of raw earth as a construction material is limited by the lack of a technical reference standard and is penalised by the current energy legislation for its massive behaviour. Research experiences, especially transoceanic, on highly performative contemporary buildings made with natural materials show that raw earth can be used, together with different types of reinforcements, to create safe, earthquake-resistant, and thermally efficient buildings. On the basis of experimental data of an innovative fibre-reinforced rammed earth material, energy analyses are developed on a rammed earth building designed for a Mediterranean climate. The paper focuses on the influences that different design solutions, inspired by traditional bioclimatic strategies, and various optimised wall constructions have in the improvement of the energy performance of the abovementioned building. These considerations are furthermore compared with different design criteria aiming at minimising embodied carbon in base material choice, costs, and discomfort hours. Results have shown the effectiveness of using the combination of massive rammed earth walls, night cross ventilation, and overhangs for the reduction of energy demand for space cooling and the improvement of wellbeing. Finally, the parametric analysis of thermal insulation has highlighted the economic, environmental, and thermophysical optimal solutions for the rammed earth envelope.


Solar Energy ◽  
2017 ◽  
Vol 141 ◽  
pp. 70-80 ◽  
Author(s):  
Lucile Soudani ◽  
Monika Woloszyn ◽  
Antonin Fabbri ◽  
Jean-Claude Morel ◽  
Anne-Cécile Grillet

2019 ◽  
Vol 282 ◽  
pp. 02087 ◽  
Author(s):  
Steinar Grynning ◽  
Alessandro Nocente ◽  
Lars Gullbrekken ◽  
Kjell Skjeggerud

Previous studies demonstrated that the use of thermal mass in buildings can contribute to reduce the energy demand and improve the thermal comfort. The thermal mass effect strongly depends on the properties of the materials facing the internal environment. High thermal capacity and conductivity are vital to achieve the desired effects. Concrete have both and it is a common building material. However, scientifically sound experimental studies that quantify the effects in a controlled environment are scarce. The aim is to study the effects of thermal mass on indoor environment and comfort in a quantifiable way in an extensive experimental campaign where comparative measurements were carried out in The ZEB TestCell Laboratory in Trondheim, Norway. The facility consists of two identical real-weather exposed rooms the size of a single person office. One of the rooms was constructed with a 70 mm thick concrete flooring, the other with an 18 mm wood-flooring. Free-floating temperature propagations were measured in different natural ventilation scenarios. The results showed that peak temperatures were notably reduced in the test room with the concrete flooring. During the warmest periods, a temperature peak reduction of more than 10% was found compared to the wooden-floored room.


2020 ◽  
Vol 12 (22) ◽  
pp. 9481
Author(s):  
Monika Gandhi ◽  
Ashok Kumar ◽  
Rajasekar Elangovan ◽  
Chandan Swaroop Meena ◽  
Kishor S. Kulkarni ◽  
...  

Many countries in the Global South have hot and dry climates with large diurnal temperature variations, which leads to large demand for space cooling—which is likely to increase with climate change. A common approach to dampen the indoor temperature fluctuations and thus reduce cooling energy demand is the use of thermal mass. However, the use of lightweight structures in many cities (e.g., high-rise structures, or for earthquake protection) precludes the use of traditional forms of thermal mass. Therefore, phase change materials (PCMs) are being widely developed as thermal energy storage systems for building applications. However, challenges such as leakage of PCMs in liquid state and their low thermal conductivity, still limit their applications in buildings. In this paper, we review the potential of Form or Shape-Stabilized Phase Change Materials (SSPCMs), which are developed by incorporating the PCM into a supporting matrix to prevent leakage in liquid state whilst improving thermal conductivity. We review different methods of preparation and the resultant thermal properties and chemical stability. We find good evidence in the literature for SSPCMs to reduce PCM leakage in liquid state, dampen indoor temperature fluctuations, and potentially alleviate peak energy demand by shifting peak loads to off-peak periods.


1971 ◽  
Vol 8 (1) ◽  
pp. 1-19 ◽  
Author(s):  
A. E. Beck ◽  
F. M. Anglin ◽  
J. H. Sass

The electrically heated cylindrical probe has often been used to measure the thermal conductivity of materials which allow the contact layer to be small enough to have negligible thermal resistance and negligible thermal mass. The probe method is not widely used in boreholes, mainly because the increased complexity of the theory required by the boundary conditions encountered in typical field situations makes it difficult to design appropriate probes and to interpret the data.This paper deals with the results of a comprehensive series of laboratory and field experiments, using cased and uncased boreholes, to investigate the importance of various design parameters and to compare the relative merits of the many proposed methods of reducing the data.It has been found that there is a surprising degree of latitude in probe design provided an uncertainty of 10% in conductivity values can be tolerated.


2014 ◽  
Vol 9 (2) ◽  
pp. 161-181 ◽  
Author(s):  
Christopher J. Whitman

Dwellings in a Mediterranean climate, such as that of Chile's Central Valley, must provide hygro-thermal comfort both during the cold winters, and the hot days and cool summer nights. Straw, once a material common in Chile's indigenous and vernacular architecture, could meet these demands when coupled with sufficient thermal mass in the form of earth renders and floor finishes. This article presents measurements of dry bulb temperatures and relative humidity, both in physical test chambers and Chilean straw bale homes. The results of these measurements confirm that straw bale construction could provide hygro-thermal comfort with heating demands 28% less than those of constructions that meet the Chilean thermal building regulations. Straw bale, therefore, could provide a viable solution for comfortable, energy efficient, rural dwellings in Chile's Central Valley. Whilst over 40 private straw bale projects have been completed in Chile to date, restrictions applying to projects receiving government subsidies prevent this technology being available to those who need it most.


AIP Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 065015
Author(s):  
Fu Yi ◽  
Xupeng Qi ◽  
Xuexin Zheng ◽  
Huize Yu ◽  
Wenming Bai ◽  
...  

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