Climatic Conditions Of Iran Research Articles

Assessing the viability of using ground-air heat exchangers during winter months in different climatic conditions of Iran

ABSTRACT Ground combined with subsurface tubes as heat exchangers, known as Ground-Air Heat Exchangers (GAHEs), have recently gained attention for heating and cooling. However, several simplifications were used to capture complex airflow characteristics in previous studies which potentiate inaccuracy in their results. This gap is addressed in this study by developing a 3D transient model incorporating realistic heat dynamics and turbulent airflow simulation using the k-epsilon model over a complete temperature cycle. The experimental result serves to corroborate the model’s accuracy. Further, the model is utilised to assess energy-conversion potential of GAHEs for heating a generic building during January in four Iranian cities with different climates. Findings show distinct differences between the GAHE’s energy-conservation capacity in these cities. The GAHE can conserve up to 714.6 kWh of energy monthly in the coldest climate and reduce peak heating loads by up to 36.0% in the hottest climate, with these averages observed across all soil types. GAHE energy saving is increased up to 27.7% when the soil around it is silt with a higher conductivity. Additionally, an adverse impact on building’s heating is created by the GAHE in some cases, highlighting the significance of hourly management of the system. Highlights A 3D transient numerical scheme was created based on fluid mechanics principles to simulate a multitube GAHE, and the solution was verified using empirical data. The effectiveness of the GAHE and its ability to reduce the maximum heating demand of a particular building for different climates within Iran in January were examined. The impact of soil characteristics on the energy-saving capability of the GAHE was found to be significant in the four cities under study, and a distinct difference in heat flux to the working fluid was discovered in different climates.

Building integrated photovoltaic with hydrogen storage as a sustainable solution in Iranian rural healthcare centers

The reliable and sustainable energy source for supplying energy demand of rural health clinic centers (RHCC) is very important especially in Coronavirus Disease 2019 (COVID-19) epidemic. However, diesel generator due to the fuel supply and environmental challenges can’t be a sustainable source. In this regard a standalone energy system based on solar with hydrogen storage/fuel cell system is proposed to solve this issue. In the present study, five regions with different climatic conditions in Iran are considered and the layout are evaluated for the first time in RHCC with a load demand of about 10 kWh/day. HOMER software is used to optimize the size of the equipment. The results showed the capacity factor (CF) of photovoltaic panels is about 17.4–20.4%, while the CF of electrolyzers is 17–25%. The CF of fuel cell remains similar at about 36–37%. The net present value of the systems ranges 22,000–27,000$ and the levelized cost of electricity ranges 0.28–0.34 $/kWh, with the lowest (highest) values in Kerman(Gylan). The proposed system reduced the consumption of approximately 1,830 L of diesel, resulting in significant environmental benefits. The hybrid renewable energy system combining solar and hydrogen storage can be considered as sustainable solution in RHCC in Iran.

Comparison of different drought monitoring indices in different climatic conditions in Iran

This study evaluates drought in different climate zones (Rasht, Shiraz, and Birjand) in Iran, using meteorological, agricultural, and remote sensing drought indices. For this purpose, NDVI, SAVI, and SR were extracted from Landsat images for 2002 and 2014-2020. Then, these indices were compared with the SPI, SPEI, and PDSI. The results indicate an increase in drought and a decrease in vegetation cover in the study area. In Rasht, where the vegetation cover is high, NDVI and SAVI were equal. In Shiraz and Birjand, where the soil effect is more significant, the distance between these two indices increased, which shows that SAVI performs better than NDVI for Shiraz and Birjand. The results also show that the drought severity could grow with decreasing rainfall and more water demand due to temperature increases, according to SPI, SPEI, and PDSI criteria. The comparison of drought indices showed that the highest correlations were between NDVI plus SAVI and SPI in Rasht, SR and SPEI in Shiraz, and NDVI and SPEI in Birjand. Based on the results of the Mann-Kendall test, the increasing trend of drought in the studied area is confirmed based on the SPI, SPEI, and PDSI. Therefore, it is suggested that remote sensing techniques combined with drought indices can be considered a suitable tool for optimal management of water resources, land use planning, and reduction of costs due to drought.

Mapping current and future risk of scorpion sting from a species with low medical concern, Mesobuthus phillipsii (Scorpiones: Buthidae) in Iran.

Scorpion stings are one of the most important health challenges and high priority research topic in public health. In this study, we aimed to model habitat suitability of the Mesobuthus phillipsii (Pocock 1889), a species with low medical concern, under current and future climatic conditions in Iran. We also identified vulnerable populations to scorpion stings in the country. Scorpion sting risk modeling was done using an ensemble approach by considering two species distribution modeling methods: MaxEnt and Random Forest methods. Distribution modeling was performed using the sdm R package. The results showed that due to climate change in 2070, the high-risk areas will increase from 20,839 to 79,212 km2. Habitats with a moderate risk of scorpion stings will also increase from 139,347 to 222,833 km2. Consequently, the number of villages in high-risk areas of scorpion stings will increase from 2,870 to 7,017, while this number will increase from 12,759 to 20,104 in the case of medium-risk villages. The results of this study can be used for scorpion stings management in Iran. This study can be used as an example for similar studies on scorpions with high medical emergency.

Evaluating the Effect of Methanolic Extract of Astragalus effusus Plant on the Hatching of Eggs of Haemonchus Species In Vitro

Introduction: Internal parasites, especially nematode infections of the digestive tract (e.g., different species of Haemonchus), have always been associated with economic losses in sheep production systems in tropical regions. Therefore, the implementation of environmentally benign treatment alternatives is essential for integrated parasite control programs. The current study aimed to evaluate the effect of the methanolic extract of Astragalus effusus plant on the hatching of eggs of Haemonchus species in laboratory conditions. Methods: This study was conducted between 2021 and 2022 in Tabriz, Iran. Haemonchus nematode eggs were extracted from experimentally infected sheep and were exposed to different concentrations (10, 20, 40, 80, and 160 mg/mL) of the methanolic extract of the plant under laboratory conditions. The hatching percentage of Haemonchus eggs was recorded after repeating the experiments five times, and the 50% and 90% inhibitory concentrations of the methanolic extract of the plant (CL50 and CL90) were estimated through regression analysis. Results: Our results demonstrated the effect of the methanolic extract of the A. effusus plant on the hatching of the eggs of Haemonchus species in laboratory conditions with satisfactory results. The effect of different concentrations of the methanolic extract of A. effusus plant from 1% to 8% (10-80 mg/mL) on the hatching of the eggs of Haemonchus species was significant, and 0.5% dimethyl sulfate was considered as the negative control of the group (χ2=0.024, P<0.05). Likewise, the inhibitory effect on the hatching of the eggs of Haemonchus species in a concentration of 16% of the methanolic extract of the A. effusus plant (160 mg/mL) was similar to the effect of albendazole (positive control). Conclusion: In laboratory conditions, the methanolic extract of the A. effusus plant was effective in preventing the hatching of the eggs of Haemonchus species, which is important to guide further studies on the other effective compounds of this plant in all stages of the life of Haemonchus because different species of the A. effusus plant have widely adapted to the geographical and climatic conditions of Iran.

Comprehensive Stability Analysis of Wheat Genotypes through Multi-Environmental Trials

In rainfed areas, due to variable environmental factors, improving the yield stability of the introduced cultivars along with increasing yield should be considered. The main aim of this study is to obtain high-yield wheat genotypes that are stable and adaptable to cold climatic conditions in Iran. For this purpose, 25 wheat genotypes were evaluated in a randomized complete blocks design with three replications during three cropping seasons (2013-2016) under supplementary irrigation and rainfed conditions. PBSTAT-GE software was used for genotype × environment interaction (GEI) analysis and comprehensive sustainability analysis. The results showed that G5, G14, G16 and G18 genotypes had good stability and general adaptation based on parametric and non-parametric stability statistics. Combined analysis of variance based on the Additive Main Effect and Multiplicative Interaction (AMMI) model showed that GEI is significant in the term of grain yield. Also, the ratios between the sum of squares G, GE and IPC1 showed that the AMMI is suitable for data analysis. GGE biplot analysis identified five mega-environments (MEs), in which ME I including E1, E2, E3, E4, E5, E6, and G7, G5, G14, G13, G16, G18, G20 being the superior ME I genotypes. According to AMMI and GGE biplote stability methods, lines G20, G18, G13, G16, G14 and Saein cultivar (G5) can be considered as desirable genetic resources in wheat production programs under variable environments in Iran, due to having the appropriate combination of yield and stability.

Neural network to quantify the amount of greenhouse gases produced by flue gases affecting climatic conditions in Iran's southern areas

The present research was conducted using neural network to investigate the climatic changes resulted by the production of greenhouse gases from flue gas condensates in the petroleum regions of southern Iran. The climatic data (humidity, wind speed, and temperature) and the activity of flue gases in an 11-year period (2008–2018) were collected to train the network. The emission of greenhouse gases and the global warming potential (GWP) values were calculated using IPCC 2006. The climatic conditions in a specific period were determined using Ivanov's climatic index. Initially, the prediction of climatic variation (by the emission of greenhouse gases from the flue gas condensates) was investigated by the linear regression of GWP and Ivonov's index lacking the suitable precision (R = 0.088). Accordingly, neural network of multilayer perceptron (MLP) and radial basis function (RBF) were used to test the correlation of GWP and Ivonov's index. The function of linear axon and the momentum training algorithm were utilized. The collected data were used for training (76%), validating (15%) and testing the network (9%). The R2 values by MLP and RBF were equal to 0.83 (mean of square error (MSE) = 0.170792332) and 0.96 (MSE = 0.063481847), indicating the two networks precisely predicted the climatic variation (global warming) resulted by the emission of greenhouse gases from the flue gas condensates. Such results are of environmental, health and economic significance, and can be used for the development of strategies, which can mitigate the climatic changes resulted by the production of greenhouse gases.

Evaluation of Seasonal, Drought, and Wet Condition Effects on Performance of Satellite-Based Precipitation Data over Different Climatic Conditions in Iran

The Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Mission (GPM) are the most important and widely used data sources in several applications—e.g., forecasting drought and flood, and managing water resources—especially in the areas with sparse or no other robust sources. This study explored the accuracy and precision of satellite data products over a span of 18 years (2000–2017) using synoptic ground station data for three regions in Iran with different climates, namely (a) humid and high rainfall, (b) semi-arid, and (c) arid. The results show that the monthly precipitation products of GPM and TRMM overestimate the rainfall. On average, they overestimated the precipitation amount by 11% in humid, by 50% in semi-arid, and by 43% in arid climate conditions compared to the ground-based data. This study also evaluated the satellite data accuracy in drought and wet conditions based on the standardized precipitation index (SPI) and different seasons. The results showed that the accuracy of satellite data varies significantly under drought, wet, and normal conditions and different timescales, being lowest under drought conditions, especially in arid regions. The highest accuracy was obtained on the 12-month timescale and the lowest on the 3-month timescale. Although the accuracy of the data is dependent on the season, the seasonal effects depend on climatic conditions.

Evaluation of stability in maize hybrids using univariate parametric methods

Genotype × environment interaction is one of the complex issues of breeding programs to produce high-yielding and compatible cultivars. Interaction of genotype × environment and make the more accurate selection, the performance and stability of hybrids need to be considered simultaneously. This study aimed to investigate stable genotypes with yield using 12 maize hybrids in different climatic conditions of Iran. The experimental design used was a randomized complete blocks design in three replications in two cropping years in Karaj, Birjand, Shiraz, and Arak stations. The simple analysis of variance performed on grain yield of genotypes indicated that all hybrids studied each year and station were significantly different in grain yield. Also, the combined analysis results showed a significant effect on the environment, the effects of genotype, and the interaction of genotype × environment and t in the studied hybrids different. Comparing Duncan's mean on the data obtained from the research, KSC705 genotypes with an average yield of 7.21 and KSC704 genotype with an average yield of 7.04 were identified as high yield cultivars. In order to identify stable cultivars, six stability parameters were used. KSC260 and KSC707 genotypes had stability Based on the environmental variance, also had stability based KSC705, KSC707 genotype on environmental the coefficient of variation, and KSC260 genotypes had stability based methods of genotype and environment interaction. As well as based on Eberhart and Russell regression coefficient had the stability to KSC400 and SC647 genotypes. Also, they were identified as the most stable genotypes based on the detection coefficient method, KSC707, and KSC703 genotypes.

Correlation Study of the Most Important Environmental Influencing Factors on the Razi MMR Vaccine.

Measles, mumps, and rubella (MMR) are among the most important viral infectious diseases in Iran and neighboring countries. After using a trivalent vaccine for these three diseases for a long time, in recent years, these diseases have been significantly controlled in Iran. One of the important points of storing the vaccine is that the vaccine strains are highly temperature-sensitive viruses. Due to tropical climatic conditions in Iran, the cold chain may not be achievable during the storage and transmission of the MMR vaccine. Therefore, the efficacy of the vaccine may be affected. This study aimed to evaluate the MMR vaccine potency at different temperatures (stress tests) and frequent light exposures. All quality control tests in the form of stability studies were performed on the samples from three consecutive batches produced during a full-scale Razi production. The samples were stored at 2-8, 22-25, 35-37, and 42-45°C in specific time intervals, exposed to frequent light, and underwent freezing/thawing conditions. According to the results, the storage of the vaccine at high temperatures caused a decrease in potency and increased moisture content in the vaccine vials. The best temperature for maintenance and transportation of MMR is 2-8°C. The time and frequency of light exposure may affect the vaccine potency. Based on the sensitivity of the vaccine strains to environmental conditions, the development of plans for storage and transportation of vaccines in different situations and training the vaccine injection staff seem necessary.

Two Comprehensive and Practical Methods for Simulating Pan Evaporation under Different Climatic Conditions in Iran

Evaporation from surface water plays a crucial role in water accounting of basins, water resource management, and irrigation systems management. As such, the simulation of evaporation with high accuracy is very important. In this study, two methods for simulating pan evaporation under different climatic conditions in Iran were developed. In the first method, six experimental relationships (linear, quadratic, and cubic, with two input combinations) were determined for Iran’s six climate types, inspired by a multilayer perceptron neural network (MLP-NN) neuron and optimized with the genetic algorithm. The best relationship of the six was selected for each climate type, and the results were presented in a three-dimensional graph. The best overall relationship obtained in the first method was used as the basic relationship in the second method, and climatic correction coefficients were determined for other climate types using the genetic algorithm optimization model. Finally, the accuracy of the two methods was validated using data from 32 synoptic weather stations throughout Iran. For the first method, error tolerance diagrams and statistical coefficients showed that a quadratic experimental relationship performed best under all climatic conditions. To simplify the method, two graphs were created based on the quadratic relationship for the different climate types, with the axes of the graphs showing relative humidity and temperature, and with pan evaporation, were drawn as contours. For the second method, the quadratic relationship for semi-dry conditions was selected as the basic relationship. The estimated climatic correction coefficients for other climate types lay between 0.8 and 1 for dry, semi-dry, semi-humid, Mediterranean climates, and between 0.4 and 0.6 for humid and very humid climates, indicating that one single relationship cannot be used to simulate pan evaporation for all climatic conditions in Iran. The validation results confirmed the accuracy of the two methods in simulating pan evaporation under different climatic conditions in Iran.

Integrated long-term planning of conventional and renewable energy sources in Iran's off-grid networks

In this study, a combined power supply system consisting of renewable solar and wind energies with backup and storage equipment including a diesel generator and a Battery Energy Storage System (BESS) with Demand Response (DR) was integrated and optimized, and optimally enhanced the reliability of the sustainable supply of the load demand. This study aimed at investigating the optimization and evaluation of the cost and advantage of combined systems for off-grid power supply in four regions with different climatic conditions in Iran, including Zahedan, Kerman, Birjand, and Hamedan. The simulation results showed that for Zahedan, the cost per kilowatt-hour (kWh) of electricity with one day of autonomy and a maximum LPSP of 5% is $ 0.312 per kWh in the first year. By optimizing and altering LPSP and the optimal number of days of autonomy under various operating conditions, the capacity of the batteries was decreased from 3870 kWh (38%) to 1860 kWh (22%), which is almost half of the previous value. Furthermore, the cost per kWh of electricity in the first year decreased from $0.312 to $0.256. According to the results, such a hybrid system is cheaper than installing each of the solar, wind, or diesel generators separately. The conditions of the other three regions were then examined and analyzed and the results showed a direct correlation between the cost of electricity and the climatic conditions of each region. However, in general, considering the Levelized Cost of Energy (LCOE) with a RE hybrid energy system for many areas away from the grid in Iran and due to climatic conditions and the trend of reducing the final cost, the utilization of renewable energy sources is economically competitive with the main grid and technically feasible. It also can meaningfully diminish environmental pollutants in line with the objectives of the Paris Agreement.

Second-generation biofuel development in iran: current state and future directions

ABSTRACT Iran is considered one of the most polluted countries in the world, where major cities have consistently dealt with severe air pollution in recent decades. Fossil fuels account for a considerable portion of greenhouse gas (GHG) emissions in urban areas of Iran. Biofuels have been touted as an effective means of reducing urban air pollution. Since biofuels are largely compatible with the vehicles in Iran, they can be blended with the fossil fuels currently produced in the country as a feasible solution to the pollution crisis. This paper investigates the potential of second-generation biofuel development in Iran. First, potential biofuel resources are identified in each province. Next, the agro-ecological and climatic conditions of Iran for biomass production are evaluated. Lastly, the challenges and opportunities associated with biofuel production are discussed. The resulting managerial insights indicate that agricultural residues and energy crops are the most suitable resources for biofuel production.

Atlas of heating: Identifying regional climate-dependent heat demands in residential buildings of Iran

Due to different latitudes and variation of altitude in geographical areas in Iran, the climatic conditions of Iran are such that the variations of the heating degree-days (HDD) are in a broad range of 60 to 3000 for residential buildings in different climatic regions. In addition, in many cases, the building design and construction processes follow patterns which do not necessarily meet national energy requirements and standards. Based on these two reasons, it is essential to identify the current status of energy consumption indicators in residential buildings. That way, it gets more convenient to adopt new strategies to improve the current state of energy consumption of buildings. In this study, heating energy consumption indices of residential buildings is investigated. Using the combination of the results of statistical data analysis, questionnaires, filled in for 500 buildings, and a reference building simulation in different climates of Iran, the heating atlas of residential buildings was prepared. According to the results, the average heating energy index (HEI) of buildings in Iran can be less than 1 to more than 41.3 (m3(N.G)/(m2·yr)) depending on climatic conditions and building design and construction quality. However, in the coldest center of province, the average of this index is 26.3 (m3(N.G)/(m2·yr)) in the hottest one that is equal 2.2. The variations of the thermal base load (supply of hot water) varied from less than 13.12 to more than 378.84 (m3(N.G)/(person·yr)). In provincial capitals, the lowest thermal base load index (TBLI) of buildings is 24.78 and the highest is 226.49 (m3(N.G)/(person·yr)). In this paper, beside charts and tables, results of heating energy consumption indices are also presented in the form of graphical atlases, i.e. color contour plots, to deliver a better picture of the whole country.

Prevalence and Risk Factors for Low Back Pain in Primiparous Women Visiting Maternity Hospitals During Different Months of Pregnancy

Objectives: Pregnancy is one of the pleasant periods of a woman’s life that turns into a bitter experience by common complications such as low back pain (LBP). Due to prevailing climatic conditions in Iran and the harmful social norms concerning Iranian women, the present study aimed to investigate the prevalence of pregnancy-related LBP and its influencing factors during different months of pregnancy. Materials and Methods: This descriptive cross-sectional study was conducted in 2019 on 550 pregnant women for LBP who were eligible based on the inclusion criteria. The research instruments were a demographic questionnaire, a LBP examination, and the visual analog scale (VAS). The obtained data were analyzed using the chi-square test, the independent t test, and multiple logistic regression in SPSS 20, and a P<0.05 was considered statistically significant. Results: The prevalence of LBP was 67.27%, and the most important factors influencing pregnancy-related LBP were maternal age (OR=950, P<0.008), gestational age (OR=1.023, P=0.015), body mass index (OR=802, P=0.045), duration of sitting (OR=1.812, P=0.036), and the duration of standing (OR=1.625, P=0.042). Conclusions: Overall, there was a high prevalence of pregnancy-related LBP in primiparous women in the present study and its predisposing risk factors included advanced maternal age, obesity, and low level of ability to sit and stand for a long time.

Detection of genomic regions associated with tiller number in Iranian bread wheat under different water regimes using genome-wide association study

Two of the important traits for wheat yield are tiller and fertile tiller number, both of which have been thought to increase cereal yield in favorable and unfavorable environments. A total of 6,349 single nucleotide polymorphism (SNP) markers from the 15 K wheat Infinium array were employed for genome-wide association study (GWAS) of tillering number traits, generating a physical distance of 14,041.6 Mb based on the IWGSC wheat genome sequence. GWAS analysis using Fixed and random model Circulating Probability Unification (FarmCPU) identified a total of 47 significant marker-trait associations (MTAs) for total tiller number (TTN) and fertile tiller number (FTN) in Iranian bread wheat under different water regimes. After applying a 5% false discovery rate (FDR) threshold, a total of 13 and 11 MTAs distributed on 10 chromosomes were found to be significantly associated with TTN and FTN, respectively. Linked single nucleotide polymorphisms for IWB39005 (2A) and IWB44377 (7A) were highly significantly associated (FDR < 0.01) with TTN and FTN traits. Moreover, to validate GWAS results, meta-analysis was performed and 30 meta-QTL regions were identified on 11 chromosomes. The integration of GWAS and meta-QTLs revealed that tillering trait in wheat is a complex trait which is conditioned by the combined effects of minor changes in multiple genes. The information provided by this study can enrich the currently available candidate genes and genetic resources pools, offering evidence for subsequent analysis of genetic adaptation of wheat to different climatic conditions of Iran and other countries.

Experimental investigation of multi‐stage solar still using phase‐change material

AbstractIn the present study, a five‐stage solar still is investigated in which paraffin wax was considered as the phase change material. Considering the climatic conditions of Iran and its locating in an arid area and shortage of freshwater resources, it is essential to produce freshwater from saline water resources. So, herein, a multi‐stage solar still as a commonly used water desalination apparatus with paraffin wax phase change materials was designed, fabricated, and tested. On the back of the collector absorber, the paraffin wax was applied for storing the additional solar energy. The results showed that the application of paraffin‐wax phase‐change agent leads to a 15% increase in freshwater production. The quantity of water generated was also studied in the flow rates of 0.7, 1.3, and 1.8 L/min with and without phase change materials. The results showed that the highest quantity of water produced is obtained in the 1.3 L/min flow rate. Finally, the quantity of water generated in the five stages of the desalination process was separately measured and found that the water produced in the first stage was 70% of the total water.

Techno-economic assessment of a hybrid system for energy supply in the affected areas by natural disasters: A case study

Natural disasters are considered as severe humankind’s challenges, which would make a large number of people homeless. Hence, it is vital to provide people with temporary shelters, energy, and freshwater. The purpose of this article is to find the most reliable and economical way to supply energy and water for the residential and health care containers in the different climatic conditions of Iran. Accordingly, a stand-alone hybrid energy system, including solar panels, small wind turbines, fuel generators, and battery banks is taken into consideration. The main objective of this research is to estimate the impact of various parameters such as the project lifetime, dispatch strategies for hybrid system control, and salvage on the optimum system. In addition, a sensitivity analysis regarding the economic and climatic parameters is performed to generalize the results for other areas. The results show that the cycle charging strategy is an appropriate controlling method for a hybrid system, especially for the short-term projects, in which the salvage value causes a high economic uncertainty. In addition, the study indicates that, due to the uniform power generation profile and the affordable cost of energy ranging from 0.130 $/kWh to 0.167 $/kWh, the hybrid system could be practically attainable. For the long-term project, the optimal renewable fraction is between 31.9% and 55.2%; while, for the short-term project, this value is between 12.5% and 21.4%. In the optimum dispatch strategy, for the project lifetime between 4 and 20 years, the impact of salvage on the final cost of the system would vary from 30% to 3%. These results highlight the importance of the salvage parameter in the economic viability of renewable systems.

Thermal Performance of Electrochromic Smart Window with Nanocomposite Structure under Different Climates in Iran

Objective: This study investigated the optimization of thermal energy consumption using electrochromic components with a new nanocomposite layer (WO3+Ag) in a larger size (window) for a room with an educational application for five cities with different climatic conditions in Iran (Yazd, Tehran, Bandar Abbas, Tabriz, and Sari). Materials &amp; Methods: For this simulation platform, the software was implemented in Energy Plus. This feasibility study was modeled by DesignBuilder software which reported reduced thermal energy consumption across all climates in Iran (hot and dry, warm and semi-humid, warm and wet, moderate and dry, and mild and humid.). Four strategies were considered for better comparison. The first strategy used for common double-glazed windows, while the second to fourth strategies involved the use of the electrochromic window in three different modes; bleached mode (Off), colored mode (On), and switchable mode (controlled below comfort conditions). Results: The third and fourth strategies indicated a reduction in thermal energy consumption in different climates from 25 to 45% relative to typical windows. The best result of cooling energy consumption was observed in Tehran. Conclusion: For this climate, the average energy consumption dropped to 34% for the warm months of the year and even 42% for the warmest month of the year (August).

An evaluation for spiral coil type earth-air heat exchanger at different climate conditions

ABSTRACT The experiments have proven that the temperature level of subsoils in the summer and winter is, respectively, lower and higher than the ambient air temperature. The buried tubes in the soil can use this potential to cool or heat the ambient air. The spiral tube heat exchanger is a good choice for earth-air heat exchangers as they are buried in a fixed buried depth, and they serve higher heat transfer coefficient due to the existence of secondary flow in the cross section of tube. In this research, the spiral tube, in an earth-air heat exchanger, has been analyzed, and the performance has been evaluated in different eras and areas of use. Cities have been selected under different climatic conditions in Iran and thus the system had been simulated in both heating and cooling modes. Furthermore, the effects of various factors, such as the depth level of buried heat exchanger in soil, the velocity and the temperature of inlet air on the exhaust air temperature, as well as the thermal load absorbed by the heat exchanger, are all being investigated. Higher buried depth of the heat exchanger increases the transferred heat, while the increase in the inlet air velocity reduces the heat exchange between the soil and the air. Tabriz which is a city located in a semi-arid climate in Iran, serves the best heating and cooling loads; whereas Babolsar another city in Iran which has a humid subtropical climate, indicates the poorest performance of all in comparison to other cities and climate levels in Iran.