Changes In Ambient Air Temperature Research Articles

Evaluating the impact of off-design CHP performance on the optimal sizing and dispatch of hybrid renewable-CHP distributed energy resources

The maturation of distributed energy resources (DER) has prompted the exploration of their deployment in commercial building applications due to their potential to supply energy at lower costs and emissions rates compared to centralized generation. While several software tools exist for evaluating the techno-economic potential of integrated renewable energy and combined heat and power (CHP) systems for distributed generation applications, many suffer from poor accuracy in capturing off-design (part load and changes in ambient air temperature and pressure) performance characteristics of microturbines, combustion turbines, or internal combustion engines. Thus, this paper presents a methodology for integrating these off-design characteristics in the mixed-integer linear program within REopt, a hybrid DER screening tool. The economic impact of the CHP off-design performance is observed through several application studies of various hybrid system configurations in different climates. Each study indicates how CHP off-design performance influences optimal sizing and dispatch decisions and therefore overall system economic value. We observe through case studies that modeling without the off-design effects, depending on the CHP prime mover and site, can result in Net Present Value predictions of hybrid systems that can be overoptimistic in frequently hot climates (up to 52 %), too conservative in frequently cold climates (up to 11 %), or unaffected (＋/−1 %) in temperate climates. Cases also highlight several advantages of hybrid systems relative to non-hybrid systems such as total economic value and the systems’ ability to mitigate potentially negative consequences attributed to off-design performance.

Association between atmospheric air temperature and blood pressure among adult population in different seasons

BACKGROUND: The prevalence of hypertension in the Arkhangelsk region is steadily increasing. Despite the progress in the diagnostics and the availability of treatment, a half of the population are unaware of their hypertension and its potential consequences, and consequently, do not adhere to the prescribed medications. This lack of awareness, coupled with the challenging climatic conditions of the northern regions, can significantly increase the risk of acute myocardial infarctions and strokes among young adults.
 AIM: To study the association between atmospheric air temperature and blood pressure among the adult population in Arkhangelsk.
 MATERIAL AND METHODS: For the purpose of this study we used blood pressure data obtained from 2342 participants individuals aged 3569 years who participated in the Know your heart study in Arkhangelsk from November 1, 2015 to October 31, 2017. Every blood pressure measurement was linked to the time-corresponding readings of atmospheric air temperature recorded by the city meteorological station. The effect of the temperature on blood pressure was assessed using linear regression analysis separately for the warm (April 16October 15) and the cold (October 16April 15) seasons.
 RESULTS: In the warm season, in the group of participants without hypertension and in those with treated arterial hypertension, high values of atmospheric air temperature (17.526.5 С) relative to the average level (8.812.2 С) were associated with a decrease in systolic blood pressure at 7.9 mm Hg (p=0.004) and 8.5 mm Hg (p=0.012), respectively, and diastolic blood pressure by 5.1 mm Hg (p=0.002) and 4.5 mm Hg (p=0.021), respectively. In the group of participants with untreated arterial hypertension, changes in ambient air temperature above (12.317.2 С) and below (6.08.7 С) the average level for this period were associated with an increase in systolic blood pressure by 11.7 mm Hg (p=0.044) and 16.9 mm Hg (p=0.004), and diastolic blood pressure by 8.9 mm Hg (p=0.018) and 13.8 mm Hg (p 0.001), respectively. In the cold season, no effect of air temperature on blood pressure was found in persons without arterial hypertension. In persons with treated arterial hypertension, an increase in air temperature in the cold season to the levels of (1.31.1 С) relative to the average level (3.91.4 С) were associated with lower systolic blood pressure by 8.5 mm Hg (p=0.001).
 CONCLUSION: The results of the study demonstrate the association between the atmospheric air temperature and blood pressure. Patients with untreated hypertension are more susceptible to fluctuations in blood pressure parallel to changes in ambient air temperature.

Life on the edge-a changing genetic landscape within an iconic American pika metapopulation over the last half century.

Declines and extirpations of American pika (Ochotona princeps) populations at historically occupied sites started being documented in the literature during the early 2000s. Commensurate with global climate change, many of these losses at peripheral and lower elevation sites have been associated with changes in ambient air temperature and precipitation regimes. Here, we report on a decline in available genetic resources for an iconic American pika metapopulation, located at the southwestern edge of the species distribution in the Bodie Hills of eastern California, USA. Composed of highly fragmented habitat created by hard rock mining, the ore dumps at this site were likely colonized by pikas around the end of the 19th century from nearby natural talus outcrops. Genetic data extracted from both contemporary samples and archived natural history collections allowed us to track population and patch-level genetic diversity for Bodie pikas across three distinct sampling points during the last half- century (1948-1949, 1988-1991, 2013-2015). Reductions in within-population allelic diversity and expected heterozygosity were observed across the full time period. More extensive sampling of extant patches during the 1988-1991 and 2013-2015 periods revealed an increase in population structure and a reduction in effective population size. Furthermore, census records from the last 51 years as well as archived museum samples collected in 1947 from a nearby pika population in the Wassuk range (Nevada, USA) provide further support of the increasing isolation and genetic coalescence occurring in this region. This study highlights the importance of museum samples and long-term monitoring in contextualizing our understanding of population viability.

Performance of Regenerative Air Preheater of Pulverized Coal Fired Boilers

Abstract: The air preheater (APH) is the final heat trap in the boiler's flue gas path. Effective pre-combustion coal drying and efficient combustion in the boiler are required for APH to operate efficiently. The effectiveness of heat transfer in APH is significantly influenced by the characteristics of relative humidity and ambient air temperature (AAT). Relative humidity (RH) and air density are also impacted by variations in AAT, which in turn alters the heat capacity of the air. If there is insufficient reserve heat exchange capacity in APH, an increase in AAT will diminish the possibility of waste heat recovery. Additionally, a change in AAT will affect the power consumption of the fans and the leakage through various seals.

The investigation of an SGT5-2000E gas turbine power plant performance in Benin City based on energy analysis

• The effect of change in ambient air temperature on the performance of the SGT5 -2000E Gas turbine Power Plant was analyzed for this location. • The average net power output was 97.33% of the guaranteed value. • For this location, a 1 0 C rise in ambient air temperature, there are drops of 1.16% in net power output and 1.58% net thermal efficiency, a 1.58% increase in SFC and HR, and a 0.64% decrease in WR. • This study has suggested efficient ways of overcome drawbacks observed. In order to address the growing global energy demand and save energy from operating gas turbine power plants, the performance and losses from existing gas turbine power plants need to be studied. In view of this, this research work aims at carrying out the energy analysis of the SGT5-2000E Gas Power Plant for off-design conditions. The energy analysis was conducted using operating data collected from the power plant to evaluate the thermal efficiencies, specific fuel consumption (SFC), heat rate (HR), work ratio (WR) and energy losses with the aid of MATLAB software. The effects of ambient air temperature and compressor pressure ratio on the thermodynamic performance were carried out. Energy analysis results obtained showed that the average net thermal efficiency of the SGT5-2000E Gas Power Plant was found to be 30.21% at the ambient air temperature range from 21 to 35 0 C, the compressor pressure ratio of 10.73 to 10.96, the net power output of 148.92MW to 160. 70MW, and 60.16% of the fuel energy input was lost to the power plant surroundings as waste heat. Also, the results obtained revealed that for a 1 0 C rise in ambient air temperature, there are drops of 1.16% in net power output and 1.58% net thermal efficiency, a 1.58% increase in SFC and HR, and a 0.64% decrease in WR. Furthermore, the results obtained showed that there was a lower performance of the plant at high ambient air temperature and a lower compressor pressure ratio and the exhaust gas waste heat can be utilized for a combined heat and power system. Accordingly, the study has provided an understanding of suitable information about the power plant that can be used for efficient operation and waste minimization as ways of performance enhancement of the SGT5-2000E Gas Turbine Power Plant in Benin City.

Unobtrusive Cardio-Respiratory Assessment for Different Indoor Environmental Conditions

The achievement of a healthy indoor environ- ment—an indispensable requirement for human well-being—relies on the establishment of good air quality conditions and thermal comfort levels. This study addresses the development of a healthcare-focused Internet-of-Things (IoT) system for the cardiac assessment using photoplethysmography (PPG) and ballistocardiography (BCG) that can be applied in any indoor environment. Results from its experimental application include the analysis of heart rate variability (HRV) and respiratory status from a group of young adults under different thermal conditions and relative humidity (RH) levels. The final goal was to investigate the effects of short-term exposure to different air temperature and humidity conditions on human thermal comfort based on the analysis of the autonomic nervous system (ANS) activity. The experiment took place in a regular and nonisothermal office environment. Simulations based on computational fluid dynamics (CFD) were conducted to estimate heat distribution and select the optimal locations for the environmental sensor nodes’ placement. Results indicated that activation of the parasympathetic system was more notable in short-term exposures to environments with different air temperatures (24 °C–30 °C) than with different levels of RH (50%–70%). Changes in ambient air temperature led to the activation of thermal regulatory reflexes and thermal discomfort, perceived by an increase in the ratio of low frequency to high frequency (LF/HF) at higher air temperature exposures. In addition, HRV parameters were used to train machine learning models on predicting if the user is in a thermally comfortable environment or a discomfortable environment (hot or humid), having achieved an 87% average accuracy.

Impact of the thickness of the wall of optical lenses on the production process stability

The article compares the stability of the production process of plastic optical lenses produced by the injection molding process. Moreover, it evaluates the effects caused by using very thick walls and very thin walls in plastic optical lenses. The injection process are divided into three fundamental stages. The first is the injection of plastic into the mold itself (filling). During this phase, 95–99% of the cavity volume is filled. The second phase is the so-called after-pressure, where the remaining cavity spaces are filled, and the part reaches dimensional stability. The last stage is called cooling. During the final phase, the element is solidified and becomes dimensionally stable in lower temperatures. In the current work, the authors compare the lenses that differ only in the maximum wall thickness. In the experiments, the conditions of changing pressure and injection speed were simulated. During injection, slight changes in the injection parameters may occur due to the random external influences. Those influences include the change in ambient air temperature, voltage fluctuations in the electrical system, machine vibrations, imperfect homogeneity of the material used, etc. The common process parameters that the organization uses by default were used as a basis. The after-pressure and injection pressure were changed to 102%, 105%, 98%, and 95% in the experiments. The results evaluate the proportion of non-conforming products (scrap) that appertain to each change in the parameters of production.
 The research proves the dependence between the thickness of the lens wall and the stability of the process. Although a higher total waste is expected for thick-walled lenses, the knowledge of the stability of the process in the production of lenses has not yet been recorded though it is a significant indicator for the production planning. It is known that a lower process stability is expected based on the design for these types of elements, and the researrchers were able to take measures to eliminate this risk and thus reduce the total waste and other negative impacts on production.
 Modifications to the mold can also achieve some improvement in this condition. The first step is to expand the cross-section of the inlet channel gate. The pressure is transmitted to the cavity through this cross-section. Its enlargement ensures a more even distribution of the pressure in the entire volume of the part. Another way to facilitate production is to guarantee optimal cooling of the cavity. It can be achieved by placing the cavity away from the hot runner system so that the cooling can be evenly distributed around each side of the part. The last way to solve the problem of collapse is to create a counter-deformation in the mold. That is to enlarge the cavity so that the lens sinks into the desired shape.
 These measures may include preventive debugging of the mold for multiple presses in case the press needs to be changed and preferably placing such elements on newer injection molding machines where parameters are less likely to fluctuate and avoiding moving such molds to presses for which they have not been debugged unless necessary. The work aims to prove the dependence between the thickness of the optical lens and the stability of the injection process. While waste percentage, cycle time, and other parameters are considered and quantified at the design stage of the optical lens, process stability has not yet been quantified. Proving the dependence between the above-mentioned phenomena will allow predicting the process stability of new lens designs more precisely.

Numerical study regarding cooling capacity for non-equidistant fillings in large-scale wet cooling towers

Fillings are the core part of wet cooling towers, and generally speaking, the fillings are arranged in an equidistant pattern, which actually hampers the heat and mass transfer process. So the non-equidistant fillings which is the combination of large-spacing and small-spacing fillings are adopted to enhance the thermal performance. In this study, numerical simulation was conducted on one real wet cooling towers equipped for a 600 MW unit to study the relatively optimal combination of 26 mm and 30 mm spacing fillings (30 mm fillings are arranged in the inner zone and 26 mm fillings are stalled in the outer zone). The simulation results indicated that, compared with conventional equidistant fillings, the thermal and resistance performance improve partly under the non-equidistant fillings pattern. After adopting non-equidistant fillings, the aerodynamic field and the temperature field improve significantly. Furthermore, with the increase of the inner zone radius R1, the water temperature drop Δt, cooling efficiency η and Merkel number N rise first and then decline, and the relatively optimal inner radius is 47.5 m in this case. When R1 = 47.5 m, compared with 26 mm equidistant fillings condition, Δt, η, and N increase about 0.13 °C, 0.8%, and 0.03. And the ventilation rate G increases by about 751.32 kg/s at most. While the ambient air temperature changes, the non-equidistant fillings can also improve the cooling performance. Under the summer typical conditions, compared with all 26 mm and 30 mm equidistant fillings, the Δt with the relatively optimal non-equidistant fillings rises by 0.17 °C and 0.2 °C, respectively.

Mechanical Characteristics and Failure Mode of Asphalt Concrete for Ballastless Track Substructure Based on In Situ Tests

Asphalt concrete paved on the surface of a roadbed as a ballastless track substructure has an excellent waterproofing and vibration attenuation performance. However, the mechanical characteristics and the failure mode of this structure under the actions of a cyclic train load and ambient air temperature changes are still unclear. Therefore, a test section of an asphalt concrete substructure was constructed based on a high-speed railway ballastless track project in north China. In situ forced vibration tests and temperature-induced deformation monitoring tests were performed to investigate the mechanical responses of the asphalt concrete, respectively. Test results show that the bottom of the asphalt concrete layer is in the tensile state under the action of the cyclic train load. The surface of the asphalt concrete in contact with the base plate is subjected to tensile stress near the expansion joint under the action of the negative temperature gradient. Changes in the ambient temperature lead to more significant mechanical responses of the asphalt concrete substructure than the cyclic train load, especially near the expansion joint of the base plate. Therefore, the passive tensile failure mode may occur near the expansion joint of the base plate. However, it has also proved that setting isolation layers under the base plate near the expansion joint is an effective method to significantly reduce responses near the expansion joint in this research.

New electrostatic precipitator with dielectric coatings to efficiently and safely remove sub-micro particles in the building environment

The influx of ambient particulate matter (PM) to the indoor environment has threatened human health due to its adverse impacts on respiratory, cardiovascular, and neurological systems. Consequently, PM removal devices with high efficiency and low cost like electrostatic precipitator (ESP) are essential for a healthy and sustainable indoor environment. Traditional two-staged ESP includes particle charging and collection part. In this study, we innovated the collection part by coating the repelling electrodes with dielectric films. Four performance influencing parameters were examined: the voltage difference (Vc) and distance (dc) between the repelling and collecting electrodes, and both the dielectric material and thickness (de). The new ESP achieved its best performance when coated with PET (de =60 μm) at dc =3 mm. The breakdown voltage was promoted from −4 kV (without dielectric film) to −9 kV, and PM removal efficiency was enhanced from 60 % to 92 %. The new ESP had low net ozone production (3–5 ppb), low pressure drop (10–13 Pa), and low energy consumption (18 W/m2), making it an eco-friendly device. Running continuously for one week, the new ESP maintained a single-pass PM removal efficiency of around 90 %, notwithstanding changes in ambient air temperature and relative humidity.

Modelling and analysis of a liquid-cooled system for thermal management application of an electronic equipment

The removal of heat from electronic components, increasingly miniaturized with high power dissipation per unit volume, is a significant industrial problem to be resolved, to avoid failures due to excessive temperatures and besides to maintain performance and operating conditions. This article describes the development of a one-dimensional thermodynamic model to simulate the cooling of electronic chips belonging to inverters for stationary PV solar arrays; these are typically located in very different environments, including deserts or very hot areas, so the operating life of theirs inverter units are strongly affected by changes in external environmental conditions. Results have shown that the model allows, with very low calculation times, to quantify the effects of cooling performance and thermal load of electronics both in design and off-design conditions: the working temperature of the components was monitored as the effectiveness of the main heat exchanger vary with the exposure to the external environment over time, in terms of fouling and as the ambient air temperature changes; in this case a simple control system was simulated to limit the maximum temperature of the chips and the air flow rate of the fans. The thermal performances of two types of glycol-based refrigerant fluids have been compared.

Design Strategies and Control Methods for a Thermally Driven Heat Pump System Based on Combined Cycles

Heating sector is one of the key emitters of greenhouse gas, and thus innovations are needed to improve the energy efficiency of heating technologies. In this paper, a recently proposed gas fuelled heat pump system that integrates an Organic Rankine Cycle (ORC) with an air-sourced heat pump (ASHP) has been further investigated. The heat produced by the gas burner is used to drive an ORC power system to produce mechanical power, which is then directly used to drive a vapour compression heat pump. Two different designs of the combined system were modelled, and their performances were compared and analysed. In the first design, the cold water is firstly heated in the heat pump condenser and then further heated in the ORC condenser to achieve the required final temperature. In the second design, the water is firstly heated in the ORC condenser and then further heated in the heat pump condenser. The results showed that the first design can achieve better overall fuel-to-heat efficiency. Using Aspen Plus, a dynamic model has then been developed to study the optimal control strategies for this design when ambient air temperature changes. The results revealed that, for the ambient temperature ranging from 7 ˚C to 15 ˚C, increasing air mass flow rate is sufficient to maintain the overall system performance. While when ambient temperature is below 7 ˚C, more heat is required from the gas burner that would reduce the fuel-to-heat efficiency.

Monitoring and Mitigation of Methane Emissions from Pressure Relief Valves of a Biogas Plant

AbstractThe two‐year monitoring (732 days) of operational methane emissions from pressure relief valves of the gasholders from an agriculture biogas plant is presented. The monitoring aimed at the identification of major factors influencing the emissions and the effect of mitigation measures deduced from the results. The determined emission factors from the valves of both gastight covered digesters are 1.8 and 0.6 % CH4 loss for the first and second year of investigation, respectively. The emission rates strongly depend on seasonal factors like (fast) changes in ambient air temperature as well as the capacity utilization of the combined heat and power and the operation of the gasholders. The implemented mitigation measures significantly reduced the measured methane emissions in the second year of the investigation.

A NEW APPROACH TO THE ANALYSIS OF THE INFLUENCE OF WEATHER CONDITIONS ON THE HUMAN ORGANISM

Despite the long history of studying the influence of meteo- and heliogeophysical factors on the human body, the mechanisms of this influence remain unclear. The inability to influence weather conditions makes it necessary to develop new, experimental approaches to such research. To analyze the effect of the ambient air temperature, atmospheric pressure, moisture and other meteorological indices on the human body, and to identify the mechanisms of such impact, there is proposed a new approach using an appropriate experimental stand (weather experimental stand). The basis of such stand can be composed of a climatic chamber, the technical characteristics of which allow carrying out research with human participation. In such studies, various physiological and biochemical indices can be monitored, as well as psychological tests can be administered. Such studies are of particular relevance in relation to the intensive development of the Arctic since in high latitudes the influence of heliogeophysical and meteorological factors is very pronounced. The climate of the Arctic is characterized by a combination of significant temperature fluctuations, atmospheric pressure, low absolute and high relative humidity, strong winds, significant changes in the geomagnetic field and atmospheric electricity, a pronounced deficit of UV radiation and light aperiodicity. Features of the natural conditions of the North, apparently, cause a high incidence of the diseases of the circulatory and respiratory system in the alien population (in comparison with the indigenous one). In addition, the article draws attention to the fact that the only weather factor, whose mechanisms of influence are sufficiently well studied, is the change in ambient air temperature, and these mechanisms were studied through research done under experimental conditions.

Photosynthesis of Sago Palm (Metroxylon sagu Rottb.) Seedling at Different Air Temperatures

Photosynthetic activities of the sago palm (Metroxylon sagu Rottb.) were studied to find out its sensitivity to changes in ambient air temperature. The minimum ambient air temperature designed for the experiment was 25–29 °C, while the higher end was 29–33 °C. Several photosynthetic parameters were studied to support our analysis in sago photosynthetic activity, including diurnal leaf gas exchange, assimilation rate vs. CO2 concentration, leaf greenness, leaf chlorophyll content, and photosynthetic rate vs. irradiance. We found that sago palm photosynthetic activity tends to be more sensitive to minimum than to maximum ambient air temperature. The plants exposed to higher air temperatures had dark green leaf color associated with higher rates of diurnal photosynthesis, chlorophyll content, and rubisco limited photosynthetic activity. They also exhibited higher trend in optimum irradiance absorption level. Consequently, maximum light energy dissipation occurred at higher temperatures.

System-level analysis of a novel air-cooled condenser using spray freezing of phase change materials

A comprehensive system-level analysis is performed for a novel air-cooled condenser based on spray freezing of phase change materials (PCMs). This novel air-cooled condenser uses PCMs to decouple the process of steam condensation and heat rejection to air in order to significantly improve air-side heat transfer and reduce steam condensation temperature as compared to conventional air-cooled condensers (ACCs). Melting of solid PCM particles in a two-phase PCM slurry flow anchors the steam condensation temperature close to the PCM melting point regardless of the change in ambient air temperature. Spray freezing of millimeter-sized liquid PCM droplets increases the air-side heat transfer coefficient by five times compared to the finned-tubed ACCs. A multiscale model, which directly captures the melting and settling of PCM particles at the microscopic level and accounts for phase change through energy source terms at the macroscopic level, has been developed to simulate the PCM slurry flow over heated tube bundles. Using this multiscale model, the effects of particle volume fraction, Reynolds number, and particle to steam tube diameter ratio on the averaged wall Nusselt number of the steam tubes are investigated. It is found that the averaged wall Nusselt number for a PCM slurry flow of 20% solid fraction achieves a 38% enhancement over the PCM single-phase flow of same Reynolds number. On the air side, the freezing/melting of PCM droplet/particle is approximated based on a 1-D transient heat conduction model and the air-side pressure drop across the PCM droplet array is determined using a 3-D k-ε turbulence model. The performance of this spray-freezing PCM ACC is compared against a baseline ACC of a 500 MWe power plant. It is found that, for comparable footprint area and ambient conditions, the spray-freezing PCM ACC reduces the initial temperature difference to as low as 16.8 °C and provides up to 10.8 MW net power production gain compared to the baseline ACC.

Dynamic Properties Modeling of the Thermoelectric Fire Sensors in the Aircraft Fire Suppression System

Abstract The paper presents selected results of work at the Air Force Institute of Technology (AFIT) in the concerning modeling the dynamic properties of fire detectors used in aviation fire protection systems. In order to determine the conditions of false fire signals, the simulation models of thermoelectric fire detectors have been developed. Simulation models were tested in Matlab-Simulink computational packages for various methods of heating and cooling the sensors (among others, changes in ambient air temperature of the sensor, caused by the EWU exhaust gas diffusers were simulated – these diffusers are used to distribute flue gases from helicopter engines).

サーマルマネキンを用いた温熱環境評価法に関する研究 （第1報）気温の変動に対するマネキン表面熱流の非定常応答特性の測定

サーマルマネキンを用いた温熱環境評価法に関する研究 （第1報）気温の変動に対するマネキン表面熱流の非定常応答特性の測定

Effect of ambient air temperature on the performance of regenerative air preheater of pulverised coal fired boilers

The air preheater (APH) is the last heat trap in flue gas path of boiler. Efficient performance of APH is possible with efficient pre-combustion coal drying and effective combustion in the furnace. The characteristic of ambient air temperature (AAT) has a significant role on the efficiency of heat transfer in APH. The change in AAT in turn changes heat capacity of air that depends on relative humidity (RH) and air density. An increase in AAT will reduce the waste heat recovery opportunity, if sufficient reserve capacity of heat exchange is not available in APH. Besides, change in AAT will have an impact on the power consumption of the fans and leakage through different seals. In this paper, the effect of these factors due to change in AAT is evaluated to assess the performance of regenerative APH with reference to a field study of 135 MWe subcritical steam power plant.

Impact of ambient conditions on evaporation from porous media

AbstractThe complexity of soil evaporation, depending on the atmospheric conditions, emphasizes the importance of its quantification under potential changes in ambient air temperature, Ta, and relative humidity, RH. Mass loss, soil matric tension, and meteorological measurements, carried out in a climate‐controlled laboratory, were used to study the effect of ambient conditions on the drying rates of a porous medium. A set of evaporation experiments from initially saturated sand columns were carried out under constant Ta of 6, 15, 25, and 35°C and related RH (0.66, 0.83, 1.08, and 1.41 kPa, respectively). The results show that the expected increase of the stage 1 (S1) evaporation rate with Ta but also revealed an exponential‐like reduction in the duration of S1, which decreased from 29 to 2.3 days (at Ta of 6 and 35°C, respectively). The evaporation rate, e(t), was equal to the potential evaporation, ep(t), under Ta = 6°C, while it was always smaller than ep(t) under higher Ta. The cumulative evaporation during S1 was higher under Ta = 6°C than under the higher temperatures. Evaporation rates during S2 were practically unaffected by ambient conditions. The results were analyzed using a mass transfer formulation linking e(t) with the vapor pressure deficit through a resistance coefficient r. It was shown that rS1 (the resistance during S1) is constant, indicating that the application of such an approach is straightforward during S1. However, for evaporation from a free water surface and S2, the resistances, rBL and rS2, were temperature‐dependent, introducing some complexity for these cases.