STRAW BALES, A POSSIBLE SOLUTION FOR HYGRO-THERMALLY COMFORTABLE DWELLINGS IN CHILE'S CENTRAL VALLEY: PHYSICAL TEST CHAMBERS AND IN SITU MEASUREMENTS

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.

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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 ◽

10.3390/buildings11120635 ◽

2021 ◽

Vol 11 (12) ◽

pp. 635

Author(s):

Miguel Ángel Mellado Mascaraque ◽

Francisco Javier Castilla Pascual ◽

Víctor Pérez Andreu ◽

Guillermo Adrián Gosalbo Guenot

Keyword(s):

Thermal Conductivity ◽

Thermal Comfort ◽

Energy Demand ◽

Winter Period ◽

Rammed Earth ◽

Thermal Mass ◽

Nominal Data ◽

K Value ◽

Earth Walls

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.

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Thermal comfort in winter incorporating solar radiation effects at high altitudes and performance of improved passive solar design—Case of Lhasa

Building Simulation ◽

10.1007/s12273-020-0743-x ◽

2020 ◽

Author(s):

Lingjiang Huang ◽

Jian Kang

Keyword(s):

Solar Radiation ◽

Thermal Comfort ◽

Energy Saving ◽

Solar Irradiance ◽

Indoor Environment ◽

Thermal Mass ◽

High Altitudes ◽

Energy Saving Potential ◽

Environment Control ◽

Passive Solar

AbstractThe solar incidence on an indoor environment and its occupants has significant impacts on indoor thermal comfort. It can bring favorable passive solar heating and can result in undesired overheating (even in winter). This problem becomes more critical for high altitudes with high intensity of solar irradiance, while received limited attention. In this study, we explored the specific overheating and rising thermal discomfort in winter in Lhasa as a typical location of a cold climate at high altitudes. First, we evaluated the thermal comfort incorporating solar radiation effect in winter by field measurements. Subsequently, we investigated local occupant adaptive responses (considering the impact of direct solar irradiance). This was followed by a simulation study of assessment of annual based thermal comfort and the effect on energy-saving potential by current solar adjustment. Finally, we discussed winter shading design for high altitudes for both solar shading and passive solar use at high altitudes, and evaluated thermal mass shading with solar louvers in terms of indoor environment control. The results reveal that considerable indoor overheating occurs during the whole winter season instead of summer in Lhasa, with over two-thirds of daytime beyond the comfort range. Further, various adaptive behaviors are adopted by occupants in response to overheating due to the solar radiation. Moreover, it is found that the energy-saving potential might be overestimated by 1.9 times with current window to wall ratio requirements in local design standards and building codes due to the thermal adaption by drawing curtains. The developed thermal mass shading is efficient in achieving an improved indoor thermal environment by reducing overheating time to an average of 62.2% during the winter and a corresponding increase of comfort time.

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Thermo-physical characteristics of building integrated phase change materials (PCM) and their applicability to energy efficient homes

10.32920/ryerson.14660997 ◽

2021 ◽

Author(s):

Omar Siddiqui

Keyword(s):

Compressive Strength ◽

Phase Change ◽

Phase Change Materials ◽

Energy Savings ◽

Physical Characteristics ◽

Comfort Level ◽

Thermal Mass ◽

Lower Phase ◽

Physical Test ◽

The Impact

The applicability of utilizing a variety of thermal mass including phase change materials with commonly used building materials is investigated through the use of simulations and physical testing. The thermal performance and occupant comfort potential of a novel solid-solid phase change material, known as Dal HSM, is compared and contrasted to commonly available forms of thermal mass. Detailed experimentation is conducted to successfully integrate Dal HSM with gypsum and concrete. The measurement of physical characteristics such as compressive strength and modulus of rupture is conducted to ensure that the PCM-composite compound retains the structural integrity to be utilized in a typical building. The use of thermal mass in the Toronto Net Zero house was found to contribute to energy savings of 10-15% when different types of thermal mass were used. The comfort level of the indoor occupants was also found to increase. The performance of Dal HSM was found to be comparable to a commercially available PCM known as Micronal in the heating mode. The cooling mode revealed that Dal HSM provided slightly lower energy savings when compared to Micronal due to a lower phase transition temperature and latent heat. The performance of physical test revealed a decrease in the compressive strength as the concentration of Dal HSM was increased in the PCM-gypsum specimens. Tests were also performed to analyze the impact of increasing the PCM concentration on the flexural strength of PCM-gypsum composite.

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Determining Favourable and Unfavourable Thermal Areas in Seoul Using In-Situ Measurements: A Preliminary Step towards Developing a Smart City

Energies ◽

10.3390/en12122320 ◽

2019 ◽

Vol 12 (12) ◽

pp. 2320 ◽

Cited By ~ 3

Author(s):

You Jin Kwon ◽

Dong Kun Lee ◽

Kiseung Lee

Keyword(s):

Land Cover ◽

Thermal Comfort ◽

Thermal Environment ◽

Smart Cities ◽

Distribution Data ◽

Sensible Heat ◽

Residential Areas ◽

Coverage Ratio ◽

Study Results

Urban heat island effects (UHIE) are becoming increasingly widespread, thus, there is an urgent need to address thermal comfort, which significantly influences the daily lives of people. In this study, a means of improving the thermal environment by spatial analysis of heat was implemented to ensure basic thermal comfort in future smart cities. Using Seoul as the study site, the relationship between sensible heat and land cover type was used to identify heat islands in this city. Thereafter, k-means clustering was employed to extract unfavourable and favourable thermal areas. High sensible heat indicates locations where environmental heat needs to be mitigated. Sensible heat distribution data were used for spatial typification to formulate an effective land cover factor to mitigate the UHIE. In-situ net radiation data measured at six sites were utilised to confirm the spatial typification of the thermal environment. It was found that expanding the green space by 1% reduces the sensible heat by 4.9 W/m2. Further, the building coverage ratio and green coverage influence the sensible heat in compact residential areas. The study results can be used to establish spatial planning standards to improve the thermal environments of sustainable cities.

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Numerical Assessment of Bioclimatic Architecture Strategies for Buildings Design in Tropical Climates: A Case of Study in Panama

E3S Web of Conferences ◽

10.1051/e3sconf/202019702006 ◽

2020 ◽

Vol 197 ◽

pp. 02006

Author(s):

Miguel Chen Austin ◽

Milvia Castillo ◽

Ángela de Mendes Da Silva ◽

Dafni Mora

Keyword(s):

Thermal Comfort ◽

Vernacular Architecture ◽

Simulation Software ◽

Indoor Environments ◽

Design Strategies ◽

Humid Climate ◽

Existing Building ◽

Numerical Assessment ◽

Development Goals ◽

Hot Humid Climate

The increasing concern expressed by building designers in Panama, due to new building-energy regulations, regarding sustainable development goals and energy efficiency, is leading architects to reanalyse their design strategies and evaluate the vernacular architecture. The main implications of the hot-humid climate characteristics stipulate that the need for cooling of indoor environments drives buildings’ design and settlements. This work aims to assess the use of bioclimatic architecture strategies in three existing building typologies design in Panama, in terms of thermal comfort performance. The approach adopted here is to compare and analyse the vernacular architecture with current architecture. Besides, to evaluate bioclimatic architecture strategies based on recent investigations and the guidelines proposed by Givony, Olgyay, among others. A numerical assessment was performed on the dynamic simulation software DesignBuilder, where the building’s passive strategies are evaluated in terms of operative temperature, relative humidity (rH), PMV, PPD, and discomfort hours (DH). All three houses, the HVA, HCA, and HRES were tested in three different locations within Panama City. Results showed that the strategies in HVA perform best for reducing rH levels, but the HRES performs best in overall thermal comfort performance, apart yet from the high rH levels encountered.

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User Thermal Comfort in Historic Buildings: Evaluation of the Potential of Thermal Mass, Orientation, Evaporative Cooling and Ventilation

Sustainability ◽

10.3390/su12229672 ◽

2020 ◽

Vol 12 (22) ◽

pp. 9672

Author(s):

Mamdooh Alwetaishi ◽

Ashraf Balabel ◽

Ahmed Abdelhafiz ◽

Usama Issa ◽

Ibrahim Sharaky ◽

...

Keyword(s):

Thermal Comfort ◽

High Altitude ◽

Air Temperature ◽

Thermal Performance ◽

Indoor Air ◽

Computer Modelling ◽

Evaporative Cooling ◽

Comfort Level ◽

Thermal Mass ◽

The Impact

The study investigated the level of thermal comfort in historical buildings located at a relatively high altitude in the Arabian Desert of Saudi Arabia. The study focused on the impact of the use of thermal mass and orientation on the level of thermal performance at Shubra and Boqri Palaces. Qualitative and quantitative analyses were used in this study, including a questionnaire interview with architecture experts living at the relatively high altitude of Taif city, to obtain data and information from local experts. The computer software TAS EDSL was used along with on-site equipment, such as thermal imaging cameras and data loggers, to observe the physical conditions of the building in terms of its thermal performance. The study revealed that the experts’ age and years of experience were important aspects while collecting data from them during the survey. The use of thermal mass had a slight impact on the indoor air temperature as well as the energy consumption, but it helped in providing thermal comfort. Use of ventilation can improve thermal comfort level. Evaporative cooling technique has a considerable impact on reducing indoor air temperature with 4 °C drop, improving the thermal comfort sensation level. The novelty of this work is that, it links the outcomes of qualitative results of experts with field monitoring as well as computer modelling. This can contribute as method to accurately collect data in similar case studies.

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Thermal behavior of a straw bale building from data obtained in situ . A case in Northwestern México

Building and Environment ◽

10.1016/j.buildenv.2017.08.015 ◽

2017 ◽

Vol 124 ◽

pp. 336-341 ◽

Cited By ~ 9

Author(s):

Ricardo Gallegos-Ortega ◽

Tonatiuh Magaña-Guzmán ◽

Jaime A. Reyes-López ◽

M. Socorro Romero-Hernández

Keyword(s):

Thermal Behavior ◽

Northwestern Mexico ◽

Straw Bale

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Rock and paleomagnetic evidence for the existence and nature of a Cayman Trough spreading center

Canadian Journal of Earth Sciences ◽

10.1139/e78-204 ◽

1978 ◽

Vol 15 (12) ◽

pp. 1930-1940 ◽

Cited By ~ 1

Author(s):

M. J. Clark ◽

J. M. Hall ◽

J. W. Peirce

Keyword(s):

Central Valley ◽

Spreading Center ◽

Small Scale ◽

Low Temperature Oxidation ◽

Crustal Accretion ◽

Temperature Oxidation ◽

Magnetic Parameters ◽

Mid Atlantic Ridge ◽

Curie Temperatures

Rock and paleomagnetic measurements have been made on a set of 54 basalts dredged from 17 stations located within the central valley of the Cayman Trough. Seventeen of the samples could be oriented with respect to the in situ vertical by the use of lava cooling ledges and stalactites.Peak remanent intensities in the Cayman Trough are lower than peak Mid-Atlantic Ridge values by a factor of 2 or 3 even after allowance is made for the latitudinal variation in geomagnetic field intensity. This difference is likely to be the result of the combined effects of relatively low saturation magnetization and more advanced low temperature oxidation of titanomagnetite in the Cayman Trough basalts.Five young, reversely magnetized basalts, similar to those found on the Mid-Atlantic Ridge, occur in the Cayman Trough sample set.Plots of the magnetic parameters of the pillow basalts with distance from the axis of the trough show broad highs or lows associated with the axis. Our interpretation is that crustal formation in the central valley has occurred recently, but it has either been rather diffuse or is now much disturbed tectonically on a small scale in comparison with the Mid-Atlantic Ridge. Analysis of the distribution of Curie temperatures suggests that crustal accretion has been slow (0.1–0.4 cm year−1 half-rate) and may have ceased in the area studied at about 0.6 Ma BP.

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