Cold Zone Research Articles

Spatial analysis of road traffic crashes and user based assessment of road safety: A case study of Rotterdam

Objective To perform a spatial analysis of Road Traffic Crashes (RTCs) and assess road safety issues from the perspective of road users. Problem statement Although many initiatives have been taken to reduce the occurrence and severity of RTCs, they continue to persist. Existing research often investigates the spatial occurrence of RTCs or the perception of road safety issues from the road user. In doing this, only a limited number of factors that contribute to RTCs can be revealed, whereas in most RTC occurrences a multitude of factors plays a role. A more integrated approach combining both knowledge areas can contribute to improving road safety. Methods RTCs that occurred from 2018 to 2020 in Rotterdam, in the Netherlands, were spatially analyzed. This was performed using Network Kernel Density Estimation (NKDE) analysis. Two zones within the study area were selected to understand road users’ perceptions of road safety through a survey. Furthermore, opinions toward possible recommendations for improving road safety were also collected through key informant interviews. Results NKDE resulted in a hot-spot map of the road segments in the study area that showed the frequency of RTCs using different colors. The road segments were classified based on the number of RTCs from 2018 to 2020, ranging from zero to 17.9 RTCs per kilometer. This led to the selection of a hot and cold spot zone for further analysis. The road user perception survey resulted in the discovery of qualitative responses that can be used to improve road safety in future and the possible recommendations would be well received by them. The key-informant interviews acted as a backup to the opinions given by the road users and provided insights on what is being done in the study area to improve road safety. Conclusion The synthesis of findings unveiled why road users perceive some areas as dangerous and which road policies need to be revised to improve road safety in Rotterdam.

Study on properties of Ultra-Lightweight Insulated Cementitious Composites for concurrent seismic and energy improving of existing RC frames

In the present paper, the properties of Ultra-Lightweight Insulated Cementitious Composites (ULICC) were investigated experimentally. Hollow Glass Microspheres (HGM) were used to improve thermal insulation capacity. The influence of water to blind ratio (W/B) and HGM volume content on the mechanical and thermal properties of ULICC mixtures was considered. The ULICC mixtures exhibited dry density of 1071–1358 kg/m3, tensile strength of 2.25–3.09 MPa, tensile strain capacity of 1.84–2.95%. Compressive strengths of ULICC were 35.2–57.1 MPa at 28 days by 100 mm cubic specimens. Noobvioussizeeffect on compressive strength was observed. The thermal conductivity coefficients ranged from 0.193 W/m.K to 0.227 W/m.K. Linear trend of compressive strength and thermal conductivity coefficient with HGM content were acquired. Three ULICC tensile curves considering compressive strength and tensile strain capacity were chosen for infills retrofitting analysis based on FEM. Skeleton curves, stiffness degradation, characteristic values, stress of ULICC plates were investigated by FEM results. FEM results indicated that infilled RC frame retrofitted by ULICC with higher compressive strength exhibited higher lateral carrying capacity. Strut effect of retrofitted infills acting at surrounding frame was enhanced due to ULICC mixture with highest strain capacity. Energy efficiency improvement was analyzed by heat transfer coefficients calculated. Energy saving requirements in Chinese codes can be met in hot summer and cold winter zone, as well as, cold zone after retrofit. Thermal insulation capacity of existing RC frames can be improved concurrently after retrofitted by ULICC.

Distribution, assembly, and interactions of soil microorganisms in the bright coniferous forest area of China's cold temperate zone

The bright coniferous forest area in the cold temperate zone of China is a terrestrial ecosystem primarily dominated by low mountain Larix gmelinii trees. Limited information is available regarding the assembly mechanisms and interactions of microbial communities in the soil in this region. This study employed high-throughput techniques to obtain DNA from myxomycetes, bacteria, and fungi in the soil, evaluated their diversity in conjunction with environmental factors, associated them with the assembly process, and explored the potential interaction relationships between these microorganisms. The findings of our study showed that environmental factors had a more significant influence on the α and β diversity of bacteria compared to myxomycetes and fungi. Microbial communities were influenced by environmental selection and geographical diffusion, although environmental selection appeared to have a more significant impact than geographical diffusion. Our study suggested that different microorganisms exhibited unique evolutionary patterns and may have different assembly modes within phylogenetic groups. Myxomycetes and fungi exhibited a similar assembly process that was mainly influenced by stochastic dispersal limitation and drift. In contrast, bacteria's assembly process was primarily influenced by stochastic drift and deterministic homogeneous selection. The community of myxomycetes and fungi is greatly influenced by spatial distribution and random events, while bacteria have a relatively stable population composition in specific regions and may also be subject to environmental constraints. Finally, this study revealed that Humicolopsis cephalosporioides, a fungus that exclusively resided in cold environments, may play a critical role as a keystone species in maintaining molecular ecological networks and was considered a core member of the microbiome.

Numerical study on thermo-solutal combined convection in a lid-driven chamber with heat/cold sources on sidewalls

The intention of the present numerical investigation is to study the combined convection in dual diffusive mode with thermal and solutal transfer in a cavity covered by a lid. The vertical walls treated with five distinct heat and cold zones. The adiabatic condition is imposed on the horizontal walls in upper and lower part. The implementation of finite volume methodology is applied to solve the leading equalities. The graphs are interpreted after carrying out the computations for a variety of parameters. The impact on the heat situation and cold situation place a momentous role on the pattern of stream and the resultant thermal, mass transport in the chamber. The influence of the leading regulatory constraints such as the ratio of buoyancy, Richardson number are examined on the streamlines, thermal and solutal transfer rates for distinct positions of the thermal and mass source. The distinct position of heat and mass source impacts the structure of the flow and the solutal, thermal rates.

Experimental study on the operating characteristic of a combined radiant floor and fan coil heating system: A case study in a cold climate zone

Experimental study on the operating characteristic of a combined radiant floor and fan coil heating system: A case study in a cold climate zone

Wild plant resources used as food in Spiti Valley: A cold arid zone of Himachal Pradesh, India

Wild plant resources used as food in Spiti Valley: A cold arid zone of Himachal Pradesh, India

A systematic review on thermal environment and thermal comfort studies in Chinese residential buildings

Amid the backdrop of the energy crisis, thermal comfort is crucial to achieve energy savings. Residential buildings are characterized by a wide range of adaptive comfort opportunities. However, there has been a lack of systematic refinement and review of residential thermal comfort field studies in China to provide valuable recommendations for energy conservation. We systematically reviewed studies on thermal environment and thermal comfort in Chinese residential buildings published in peer-reviewed journals up to 2020. A total of 34 studies were deemed to have provided sufficient information on both the thermal environment and thermal comfort. We found that in winter, there were obvious differences between urban and rural dwellings in Severe Cold (SC) and Cold (C) zones, with regard to their indoor air temperature (urban: 19.8 ∼ 25.0 °C v.s. rural: 11.3 ∼ 17.8 °C) and neutral temperature (urban: 17.6 ∼ 25.1 °C v.s. rural: 11.9 ∼ 23.45 °C). While in summer, the indoor air temperature in urban dwellings were slightly lower than those in rural areas due to their prevalent use of air conditioner (urban: 26.1 ∼ 28.9 °C v.s. rural: 29.5 ∼ 34.9 °C). Indoor air temperature and neutral temperature varied considerably in different climate zones in winter. In SC zones, the indoor environment was overheated, which could lead to energy wastage and overheating discomfort for residents. Residents in Hot-Summer and Cold-Winter (HSCW) zone were the most tolerant to the variation of thermal environment (the median coefficient of MTS or TSV equation: SC: 0.18; C: 0.20; HSCW: 0.13; HSWW: 0.23).

Biostratigraphy and Climate Change in the Late Miocene Age Based on Foraminifera in the Oyo Formation, Oyo River Section, Gunung Kidul, Yogyakarta

The date of the paleoclimate event was ascertained using a biostratigraphic analysis. The thickness of the Oyo Formation was measured using measurements with a Jacob stick method, yielding a thickness of 80.8 meters and 23 rock samples. In the Southern Mountains Zone, new result of the age of the upper part of the Oyo Formation by biostratigraphy investigation of the hill Late Miocene (9.79 Ma to 5.78 Ma). Biostratigraphic investigation in the Oyo River revealed 28 species and 9 genera, with two datums. The study area was classified into three biozonations based on the datum found Globorotalia acostaensis/M13a/N16 zone, the lower Globorotalia plesiotumida/M13b/N17 zone, and the upper Globigerinoides conglobatus/M14/N17 zone. The results of a paleoclimate analysis on the Oyo River Section show a general cooling tendency in the study area. Seven paleoclimate zones can be determined from these trends consisting of four warm and three cold zones. Zone I (warm), zone II (cold), zone III (warm), and zone IV (cold) have the coldest peak in the study region in 8.3 Ma, zone V (warm), and zone VI (cold), followed by zone VII (warm). Based on the correlation with other studies (South China Sea, Pacific Ocean, Oyo River, Ngalang River, and Ngioro Section), paleoclimate events in the study area occur globally.

Mutual feeding mechanism of carbon, nitrogen and enzyme activity in Northeast China black soil under snow cover change

Projected future changes in snow cover patterns associated with global warming in cold zone ecosystems could affect soil biochemical cycling. However, the effects of snow cover changes on soil available carbon, nitrogen and enzyme activities and their potential response mechanisms have not been clarified. Therefore, from November 2021 to April 2022, this study conducted a snow depth manipulation test of four treatments in the northeast black soil region, and divided the test period into five stages to measure soil temperature and humidity, microbial biomass, enzyme activity, and available carbon and nitrogen. The results showed that the decrease of snow cover increased the freeze-thaw cycle frequency and freezing temperature of soil, but decreased the soil water content. Soil total organic carbon and inorganic nitrogen contents were increased in early and deep snow periods, while snow treatment was on the contrary. Due to the release of soluble nutrients caused by frequent freeze-thaw processes, Soil soluble organic carbon and Soil soluble organic nitrogen contents increased with the decrease of snow depth in deep snow period, snowmelt period and subsequent early crop growth period. Snow treatment increased soil microbial carbon and nitrogen content in early winter and early spring because snow provided heat insulation. Soil enzyme activities increased with the increase of snow cover. Compared with the control, soil urease activities and sucrase activities increased by 18.5 % and 11.5 % under snow treatment, and decreased by 23.2 % and 10.8 % under snow reduction treatment. In addition, soil soluble organic matter was a controlling factor for soil microbial biomass and enzyme activity throughout winter. The direct effect of soil soluble organic carbon and nitrogen on soil enzymes will make soil enzymes participate in the cyclic transformation process of available carbon, thus forming a closed loop of mutual feedback between soil available carbon and nitrogen and enzymes. These results demonstrated that the changes of snow cover in the future will have certain effects on soil carbon and nitrogen cycles and enzyme activities and hence biogeochemical cycling in terrestrial system of earth.

Low-temperature solar thermal-power systems for residential electricity supply under various seasonal and climate conditions

In this work, the performance of low-temperature (<100 °C) solar thermal-power systems to satisfy residential electric loads was analyzed. The solar-driven system was designed to provide a fraction of the total electricity demand in a complementary operation with the electric grid. The analysis was conducted for an coperation during seven days each season, considering real solar and climate variables and residential loads at different climate zones in the United States. The efficiency of the system strongly depends on the solar radiation profile and the ambient temperature. Maximum efficiencies of around 9.5% were obtained in the cold and marine climate zones due to the high solar energy input and low heat dissipation temperatures. In these two zones, the system could supply more than 98% of the electricity demand all seasons. At mixed-humid and hot-humid regions, the system supplied around 50% of the electric load in three of the four seasons, but it only supplies about 27% of the electricity needs in the mixed-humid zone during summer and hot-humid zone during winter. The effect of the solar collector field area and the tank volume was also analyzed. In general, larger solar fields positively impact the efficiency. However, the impact of the tank volume varies depending on the solar radiation profile and the load requirements. Average efficiencies for the seven-day operation can be larger than 6% with a proper selection of the solar collector area and tank volume for an Organic Rankine Cycle with a capacity of about 2.6 kW. Finally, an economic analysis of the system was conducted, and the results were compared with a solar PV + battery system of similar capacity. It is expected that the cost for the analyzed solar-thermal system decreases in the coming years with the increased interest on low temperature applications.

Effects of organic mulching on moisture and temperature of soil in greenhouse production of tomato under unheated greenhouse cultivation in the cold zone of China.

In the cold zone of China, winter is cold and long and has a short duration of sunshine. Unheated earthen-wall solar greenhouses are used for tomato production in winter in this region. This was an experimental investigation of different organic mulching materials (newspaper, bran, and grass) on the soil temperature, soil moisture, tomato yield, fruit quality, and water use efficiency. Organic mulching variously improved soil temperature, soil moisture, water use efficiency, and tomato yield, which is very important for greenhouse winter cultivation in this cold zone. Organic mulching regulated the soil temperature, with daily soil temperature ranges of bran, newspaper, and grass treatments being 1.6, 1.9, and 2.1°C lower than for bare land, respectively. Compared to bare land, newspaper mulching had little effect on soil temperature and fruit quality, but increased soil moisture (14.1%) and water use efficiency (WUE: WUEb, 31.3%; WUEy, 30.6%), and greatly increased yield (81.8%) and biomass (82.7%); bran mulching greatly increased soil temperature, moisture (16%), and WUE (WUEb, 60.1%; WUEy, 44.3%) and increased biomass (30.2%) and yield (17.3%); grass mulching greatly increased soil temperature and moisture (20.9%) and increased biomass (17.9%), yield (11.2%), and WUE (WUEb, 20.5%; WUEy, 13.6%). In addition, organic mulching had a good water retention effect on soil layer above 30 cm. The total soil water consumption during tomato growth was in the following order: newspaper (103 mm) > bare (74 mm) > grass (73 mm) > bran (60 mm). Soil water consumption mainly occurred in the 0- to 10-cm soil layers.

Polyproline type II helical antifreeze proteins are widespread in Collembola and likely originated over 400 million years ago in the Ordovician Period

Antifreeze proteins (AFPs) bind to ice crystals to prevent organisms from freezing. A diversity of AFP folds has been found in fish and insects, including alpha helices, globular proteins, and several different beta solenoids. But the variety of AFPs in flightless arthropods, like Collembola, has not yet been adequately assessed. Here, antifreeze activity was shown to be present in 18 of the 22 species of Collembola from cold or temperate zones. Several methods were used to characterize these AFPs, including isolation by ice affinity purification, MALDI mass spectrometry, amino acid composition analysis, tandem mass spectrometry sequencing, transcriptome sequencing, and bioinformatic investigations of sequence databases. All of these AFPs had a high glycine content and were predicted to have the same polyproline type II helical bundle fold, a fold unique to Collembola. These Hexapods arose in the Ordovician Period with the two orders known to produce AFPs diverging around 400 million years ago during the Andean-Saharan Ice Age. Therefore, it is likely that the AFP arose then and persisted in many lineages through the following two ice ages and intervening warm periods, unlike the AFPs of fish which arose independently during the Cenozoic Ice Age beginning ~ 30 million years ago.

Highly Linear RMS Microwave Power Sensor Joule-Heating-Based Using CMOS Technology

This article presents the design and implementation of a high-power handing capacity, wideband, and excellent microwave-dc linearity root-mean-square (rms) microwave power sensor (PS) in 180-nm standard RF CMOS technology. The detection technique utilizes two well-matched microwave power absorbers and a balanced Wheatstone full bridge (WFB) with thermistors to produce a dc output proportional to incident microwave power. The lateral spacing between the hot and cold zones of WFB with 80, 100, 120, 140,and 160 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mu}$</tex-math> </inline-formula> m has been investigated experimentally, which provides insight into the proper adjustment of the layout parameters. The experimental result of the vector network analyzer (VNA) shows that the input reflection loss is less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 22.3 dB in the frequency range of 0–20 GHz. This indicates that the designed microwave PSs have good impedance matching characteristics. Moreover, it is demonstrated that the inherent linear relationship between the output dc voltage and the incident microwave power is less than 1.6% over a dynamic range of 1–500 mW. The proposed microwave PS can be further integrated in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{X}$</tex-math> </inline-formula> -band RF transceivers, offering high microwave-dc linearity, acceptable sensitivity, small size, and low cost for improving power transfer efficiency and optimizing the performance of the transmitting and receiving chain.

Effects of climate change on long-term building heating performance of medium-deep borehole heat exchanger coupled heat pump

The medium-deep borehole heat exchanger (MDBHE) coupled heat pump (HP) is a promising building heating solution for carbon reduction. Existing studies claim that the MDBHE-HP suffers a bottleneck challenge of long-term heating performance degradation because of the heating extraction attenuation of the MDBHE, which largely hinders the practical applications of the MDBHE-HP. This study innovatively proposes and justifies that climate change positively compromises the heating extraction attenuation of the MDBHE and significantly improves the long-term building heating performance of the MDBHE-HP. Climate change reduces the building heating load, which mitigates the heating extraction attenuation of the MDBHE, thereby reducing the unmet level of the building heating load. The mitigated heating extraction attenuation enhances the coefficient of performance of the MDBHE-HP, thereby reducing the heating energy consumption. Case studies of 30-year operation in the severe cold and cold zones of China with different geological conditions show that while the heating extraction attenuation of the MDBHE increases the heating energy consumption by 5.0% – 8.7%, climate change reduces the heating energy consumption by 9.2% – 17.0%. Moreover, climate change reduces the unmet level of the building heating load by 70.5% – 100%. Therefore, the positive effects of climate change on the long-term building heating performance of MDBHE-HP should be considered, which contributes to promoting the practical applications of the MDBHE-HP for low-carbon building heating.

Nature and origin of an undetected seismic phase in waveforms from Southern Tyrrhenian (Italy) intermediate-depth and deep earthquakes: first evidence for the phase-A in the subducted uppermost lithospheric mantle?

We have found a previously unreported later seismic phase in seismograms of European seismic stations from intermediate-depth and deep earthquakes of the Southern Tyrrhenian subduction zone. We observe this phase at stations from 6 to 9° from the epicentre, towards north. Only seismograms of earthquakes located in a well-defined region of the slab, in the depth range of 215–320 km, show the later x-phase. In this work, we describe the nature and possible origin of this phase, and we provide a simple 2D model to explain the observed arrival times. Our analyses reveal that the x-phase propagates downward in a high velocity layer, possibly located within the deepest part of the slab. We suggest that this layer reveals the presence of the dense hydrous magnesium silicate phase A, introduced from petrological laboratory experiments, inferred to carry water in the upper mantle and predicted to be found in cold subduction zones.

Efficient conversion of ethanol to electricity using large-scale flat-tube solid oxide fuel cells

Conversion of renewable energy sources like bioethanol to electricity using solid oxide fuel cells (SOFCs) is promising to reduce the consumption of fossil fuels and to mitigate global warming. However, direct ethanol-fed SOFCs are susceptible to carbon deposition on Ni-based anode. In this study, the power generation from and degradation mechanism of large-scale flat-tube SOFCs by direct internal reforming of ethanol are investigated. The steam/carbon (S/C) ratio causes minor influence on the cell performance but considerably affects the long-term durability. Elevating temperature improves ethanol conversion rate and cell performance. Ethanol is efficiently reformed by the thick anode support and long anode channels, with low selectivity for CH4 and C2H4. Stable power generation with current density of 200 mA/cm2 is obtained over 300 h under S/C = 2 and 3 at 800 °C. Due to the high operating temperature and complex cell structure, the in-situ measurements of the temperature and gas compositions within the cell, related to carbon deposition, are difficult. The distributions of the gas compositions and temperature within the cell before and after the durability test are clarified by simulation. Simulation results reveal that, in addition to CH4 and C2H4, the cold zone near inlet contributes to carbon formation.

Progressive lawsonite eclogitization of the oceanic crust: Implications for deep mass transfer in subduction zones

Abstract Lawsonite eclogites are major hosts of H2O and trace elements and thus key for long-term deep element cycling in subduction zones. Existing cycling models suggest that the subducting oceanic crust transforms to lawsonite-eclogite assemblages; yet the scarcity of lawsonite eclogites in the rock record questions to what extent the oceanic crust transforms to lawsonite-eclogite assemblages during subduction. Here, we use petrological modeling coupled with geodynamic calculations for a typical subduction zone to show that the occurrence of lawsonite eclogites is controlled by the maturation of the subduction zone. We find that lawsonite eclogite does not form in infant subduction zones; with time, the oceanic crust forms lawsonite assemblages, but prograde heating obliterates lawsonite except in rocks exhumed prior to such heating. Lawsonite-eclogite assemblages in the oceanic crust form and survive prograde metamorphism only in mature and cold subduction zones but still necessitate specific characteristics during exhumation to preserve lawsonite. We show that the stability of lawsonite in mature subduction zones is hindered by hybridization between the mafic crust and the overlaying mantle wedge material; by contrast, lawsonite proportion increases with intense seafloor alteration and Ca-Al metasomatism. These latter processes are thus key for enhancing recycling. We argue that lawsonite-driven mass cycling to the deep mantle is important in mature subduction zones, but the role of lawsonite eclogite in carrying mass deep into Earth in the infant stage of a subduction zone is minor.

Performance analysis of a novel solar assisted ground source heat pump water heating system with graded thermal energy storage

The solar assisted ground source heat pump system (SAGSHP) is recognized as an efficient, clean and economical renewable energy technology for hot water supply. However, in SAGSHP systems with an all-day hot water supply, the solar collectors can only heat the water tank with intense solar radiation, which wastes moderate and weak solar resources. In addition, as the SAGSHP system draws heat from the soil for a long time, the soil temperature around the borehole decreases, causing the performance of the GSHP to deteriorate. To solve the above problems, a SAGSHP system with graded thermal energy storage (SAGSHP-GTES) was proposed. This paper investigated the performance and feasibility of the SAGSHP-GTES system, using a case study of hot water supply in a campus dormitory in Changsha, China. Firstly, the drawbacks of solar energy utilization in the conventional SAGSHP system were analyzed. Then, the SAGSHP-GTES system was modeled by TRNSYS, and its operational performance was evaluated and compared with the conventional SAGSHP system. Finally, the feasibility and performance of the SAGSHP-GTES system in different climate zones of China were analyzed. The results showed that the conventional SAGSHP system had a poor solar energy utilization efficiency, with an average thermal efficiency of the SC (ηSC) of only around 19.4%. The long period of operation caused the soil temperature to drop from 18.1 °C to 2.78 °C, which led to a decrease in system efficiency and an increase in electricity consumption. By controlling the heat collection of the SC and the graded utilization of solar energy in the SAGSHP-GTES system, a high ηSC of around 42.7% was obtained, which improved the system efficiency while eliminating the problem of soil temperature drop. After 15 years of operation, the soil temperature increased from 18.1 °C to 19.9 °C, which led to an increase in the coefficient of performance of the system (COPsys) from 3.77 kW/kW to 3.84 kW/kW and COPGSHP from 3.45 kW/kW to 3.5 kW/kW, and a reduction in electricity consumption from 51,746 kWh to 50,735 kWh. In addition, the conventional SAGSHP system was not feasible in severe cold zones (Harbin) and cold zones (Beijing) of China, where soil temperatures fell below 0 °C and freezing of the circulating fluid occurred, while the SAGSHP-GTES system showed excellent performance in all climatic zones of China and is a feasible and efficient technology for hot water supply.

Thermal energy storage and losses in various types of masonry concrete walls

This study investigates the thermal performance of various masonry walls, with and without plaster, for cold zones in terms of their energy storage and loss. Besides a traditional concrete mixture, twenty-five additional mixtures were selected from among 400 mixtures reported in the literature. A computational fluid dynamic (CFD) model that was implemented using ANSYS Fluent is employed here to study the heat transfer from a reference room condition (20 °C) to a cold ambient condition (−20 °C) over a period of 6, 12, and 24 h to facilitate the comparison between different walls. The model was validated using a reported experimental test via a hot plate setup. The results show that among the investigated walls, a mixture with wood shives (WS1) has the maximum stored energy (92 % over 24 h) and the minimum energy loss (8 %) in the total heat transfer from the reference room to the ambient. On the other hand, the minimum energy storage (40 %) and maximum loss (60 %) were observed for hempcrete (HC11). It was found that the combination between thermal properties (thermal conductivity, specific heat capacity, and thermal diffusivity) governs the thermal behavior of each type of concrete. The stored energy inside the wall is drastically influenced by the production of density and heat capacity and secondarily by thermal conductivity, whereas the energy loss is significantly affected by thermal conductivity and diffusivity and secondarily by the heat capacity and density as they raise the wall temperature. It is noted that the plaster reasonably reduces energy loss but has no impact on energy storage.

Hygrothermal Properties Analysis of Bamboo Building Envelope with Different Insulation Systems in Five Climate Zones

Laminated bamboo lumber (BLL) and bamboo scrimber (BS) are potential environmentally friendly building materials, considering that they are hygroscopic materials and that their hygrothermal performance is closely related to the occupants’ comfort, their building durability, and building energy consumption. This study carried out material property tests on bamboo-based materials (BLL and BS) and analyzed hygrothermal performance simulations on bamboo exterior wall constructions in five major climatic zones using WUFI. Results show that BS had a greater heat storage capacity than BLL. However, BLL showed a relatively higher moisture sorption capacity, and BLL was more easily permeated by vapor than BS. The water content (WC) of 12 walls of BLL and BS was below 20%. BLL and BS met the requirements of the envelope, and the WC of BS was lower than that of BLL. Based on the results, the walls designed in this study are suitable for the corresponding climate zones. In the cold and severe climate zones especially, the external insulation system walls performed better than the internal insulation system. The external insulation system was recommended for these two climate zones. The design and simulation results of walls made of two types of bamboo-based materials provide a scientific basis for the application of the material.