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

Multi-index drought indices are based on a combination of single drought indices and able to monitor the overall status of drought in a certain location. The aim of the present paper is to compare two recently developed multi-index drought indices, i.e., Joint Deficit Index (JDI) and Multivariate Standardized Precipitation Index (MSPI) under different climatic conditions of Iran. Although these drought indices are calculated using different statistical methods, they need twelve modified Standardized Precipitation Index (SPImod) corresponding to 12 time windows from 1 to 12 months as the input variables. In this study, these indices were calculated using the monthly precipitation data of 42 weather stations representing diverse climates of Iran during the period of 1966–2010. JDI and MSPI were compared from different viewpoints including temporal behavior, the relationship between drought severity and duration and frequencies of drought classes. The results showed that both indices have a similar trend of drought severity at all stations. Unlike the MSPI, the JDI faced two substantial problems in all stations of interest: 1) The lowest value of the JDI time series was frequently repeated in different parts of its time series, 2) The JDI was not able to identify the peak of drought severity during the critical drought periods. While the JDI could not identify the extreme (at about all stations) and very severe (at one third of stations) drought classes, the observed frequencies of the MSPI’s drought classes successfully matched the corresponding expected frequencies. The obtained results clearly indicate the superiority of the MSPI for monitoring overall status of droughts in different climatic conditions of Iran in comparison to the JDI.

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.

As the world population grows rapidly, and the limited amount of fossil fuels begins to diminish along with their impact on the environment, countries have been taking action to promote a greater use of renewable energy resources. In this article, the feasibility of providing electricity from a hybrid power system (HPS) comprising diesel/wind/photovoltaic (PV), and battery considering residential, public, and commercial buildings, consuming the largest portion of energy in Iran is investigated. Tehran, Kish Island, and Binalood are the chosen cities in Iran with distinctive geographic and climatic conditions. In order to determine the optimal design and operational planning of the HPS, the hourly electricity demand data is required to be over 8760 hs during a 1‐yr study. The required hourly data was calculated by employing Carrier (HAP4.5) software. The economic analysis is performed based on net present cost (NPC), cost of energy (COE), diesel consumption, and renewable fraction for all cases by applying HOMER software. Furthermore, sensitivity analyses are carried out to specify the impact of fuel cost on the system by considering two different diesel fuel systems. The results of the economic analysis indicate that Kish Island with warm and temperate climatic conditions would be the optimum zone to install HPS for supplying the energy demand of projected buildings. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 614–623, 2019

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

Evaluation of single crop coefficient curves derived from Landsat satellite images for major crops 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.

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.

Recent research studies have shown the advantages of using double-skin façade (DSF) and phase change material (PCM) in reducing the amount of building heat, especially for tropical and subtropical climates. Also, by adding photovoltaic (PV) cells in the facade of buildings, the solar heat of the building can be reduced and the electricity generated can lower the energy cost of the building. Since there is a strong interdependence among the energy performance of DSF, PV, and PCM as well as weather conditions, geography, and building orientation, in this paper, their simultaneous energy performance is studied under different climatic conditions of Iran. Also, all the cases are compared from an economic point of view. Based on the results obtained in this research, it can be concluded that the implementation of DSF and integration of PCM with it in the Mediterranean climate, the cold semi-arid climate, and the warm semi-arid climate of Iran is technically possible and offers the benefits of energy saving by changing the quality of spaces by using daylight as well as controlling the solar system, natural ventilation, sound insulation, and thermal insulation in winter and summer.

Drought is one of the main natural causes of damages to the ecosystems, agricultural productions, water resources, etc. Many indices have been developed to assess drought severity. Reconnaissance Drought Index (RDI) and Effective Reconnaissance Drought Index (eRDI) are two of the newest indices in drought evaluation. These indices are based on ratio of precipitation and potential evapotranspiration. In this study meteorological data of 22 synoptic stations with different climatic conditions in Iran during 1967–2014 were used to calculate values of RDI and eRDI indices. According to the result of means comparison of RDI and eRDI values, in stations with humid condition such as Ramsar and Bandar Anzali difference of the means between RDI and eRDI indices were not significant at 5% level, but in stations with hyper arid and arid condition such as Chahbahar, Bandar Lengeh, Yazd and Zabol, difference of the means in RDI and eRDI was significant at 5% level. Therefore, it is suggested to replace RDI with eRDI in regions with hyper arid and arid conditions, but in regions with sub-humid and humid conditions because of the similarities between RDI and eRDI, RDI index (without need to calculate the effective rainfall) was used.

Comparability analyses are performed to investigate similarities/differences of the standard precipitation index (SPI) and the reconnaissance drought index (RDI), respectively, utilizing precipitation and ratio of precipitation over potential evapotranspiration (ET0). Data are from stations with different climatic conditions in Iran. Drought characteristics of the 3-month, 6-month and annual SPI and RDI time series are developed and Markov chain order dependencies are investigated by the Log-likelihood, AIC and BIC tests. Steady state probabilities and Markov chain characteristics, i.e., expected residence time in different drought classes and time to reach “Near Normal” class are investigated. According to results, both indices exhibit an overall similar behaviour; particularly, they follow the first order Markov chain dependency. However, climatic variability may produce some differences. In several cases, the “Extremely Dry” class has received a more critical value by RDI. Furthermore, the expected residence time of “Near Normal” class and expected time to reach “Near Normal” class are quite different in a number of cases. The results show that the RDI by utilizing the ET0 can be very sensitive to climatic variability. This is rather important, since if the drought analyses are for agricultural applications, utilization of the RDI would seem to serve a better purpose.

Soil isolates of Aspergillus section Flavi from Mazandaran and Semnan provinces with totally different climatic conditions in Iran were examined for aflatoxins (AFs; B and G types), cyclopiazonic acid (CPA) and sclerotia production. A total of 66 Aspergillus flavus group strains were identified from three species viz. Aspergillus flavus, Aspergillus parasiticus and Aspergillus nomius in both locations. A. flavus (87.9%) was found to be the prominent species followed by A. nomius (9.1%) and A. parasiticus (3.0%). Only 27.5% of A. flavus isolates were aflatoxigenic (B(1) or B(1) and B(2)), out of which approximately 75% were capable to producing CPA. All the A. parasiticus and A. nomius isolates produced AFs of both B (B(1) and B(2)) and G (G(1) and G(2)) types, but did not produce CPA. Sclerotia production was observed in only 4 isolates of A. flavus among all 66 isolates from three identified species. A. flavus isolates were classified into various chemotypes based on the ability to produce aflatoxins and CPA. In this study, a new naturally occurring toxigenic A. flavus chemotype comprising of two strains capable of producing more AFB(2) than AFB(1) has been identified. A relatively larger proportion of aflatoxigenic A. flavus strains were isolated from corn field soils of Mazandaran province which indicate a possible relationship between high levels of relative humidity and the incidence of aflatoxin-producing fungi. The importance of incidence of Aspergillus section Flavi in corn field soils regard to their mycotoxin production profiles and crop contamination with special reference to climatic conditions is discussed.

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 & 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).

A financial comparative study of solar and regular irrigation pumps: Case studies in eastern and southern Iran

Purpose Present research focus on using solar energy as a renewable option for office buildings in different climatic conditions in Iran. To seeking a way to use clean solar energy and reduce current expense in buildings an investigation carried out. Nine office buildings in various climatic regions selected as case studies. Through a precise examination, buildings specifications, energy demand and climate information carried out. In the first step based on the buildings type and hot water demand, solar water heater systems designed for each case. In the second step, a cost-benefit analysis is done to detriment the economic aspects of implement aforementioned type of solar system. A cost-benefit analysis is done from saving energy and return time of investment point of view. Results indicate that solar water heater with low investment about US$500 and payback time between 2 and 5 years can be noticed as a desirable renewable option in case studies. Furthermore, analysis reveals that thermal load of building is more effective on fuel saving in building, while solar radiation intensity has more effective on the payback in solar water heater utilization. Design/methodology/approach In this study based on thermal load of nine building office and radiation of different part of Kermnashah province, the possibility of solar water system is investigated. Findings Analyses reveal that the thermal load of building is more effective on fuel saving, while solar radiation intensity has more effective on the payback in solar water heater utilization. The main originality goes back to consideration of different meteorological conditions in solar water heater selection.

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