Increase In Ambient Temperature Research Articles

Rotation induced by non-uniform gas–solid phase reactions of a non-spherical particle

• The particle rotation induced by gas–solid phase reactions is revealed; • The non-uniform gas–solid phase reaction directly results to the rotation of non-spherical particle; • The rotation characteristics of coal particle during combustion are discussed. Particle rotation plays an important role in gas–solid flow. The particle rotation induced by gas–solid phase reaction is investigated in this work. The non-uniform gas–solid phase reaction direct results to the rotation of a non-spherical particle. Based on the random distribution of active sites, the combustion of non-spherical particles is numerical investigated. According to the numerical results of chemical reaction rate on the particle surface, the net force and the rotation frequency of non-spherical particle were obtained by post-processing. The bearing force and rotation of cubic particles caused by gas–solid chemical reactions are systematically numerically studied. The rotational frequency is basically consistent with the experimental results in the reference. For coal char particles with an active area ratio of 0.8, the rotational frequency can reach 1000 Hz at side length of 60 μm. The effects of active area ratio, ambient gas temperature and particle size on the induced thrust and the rotational frequency of coal char particles are analyzed. The unbalanced force on the particle surface increase with the reaction rates. The rotation velocity increases with the decrease of particle size. And it increases with the increase of ambient temperature..

Molecular dynamics study on the interfacial characteristics in the process of sub/supercritical evaporation

The evaporation processes of single droplet in the nitrogen/n-dodecane binary system were studied using molecular dynamics simulation. The evolution of the vapor–liquid interfacial region of the droplet and the thermodynamic and transport properties of the fluid in the interfacial region were investigated. The simulation results show that the increase of ambient temperature has a more promoting effect on the diffusion of supercritical fluid than that of ambient pressure. Both ambient temperature and pressure can accelerate the contraction of bulk liquid. The enthalpy increases linearly throughout the evaporation process with the temperature, but there is a bulge near the critical point, while the specific heat capacity at constant pressure meets jump near the critical point. Besides, the transport properties of the supercritical fluid are similar to gas. Therefore, the transport properties of the supercritical fluid can be regarded as that of gas in engineering application.

Thermo-hydrodynamic Airflow Behavior Analysis in Solar Chimney Device

A numerical methodology has been developed to analyze the thermo-hydrodynamic aspect of airflow occurring in solar chimney power plants (SCPP) according to some dominant parameters. The general curvilinear coordinates finite volume method (GCCFVM), which is necessary in the case of turbulent flow through complex geometries, is used in this work. The governing equations describing the steady state turbulent fluid flow are solved numerically using this technique. It is shown that the chimney tower dimensions control directly the hydrodynamic field. However, the collector dimensions control directly the thermal field and indirectly the hydrodynamic field. It is demonstrated that the solar radiation influences strongly and positively the thermo-hydrodynamic field by increasing the mass flow rate. The mass flow decreases with the increase of the ambient temperature and then the system is more efficient with low ambient temperature. Indeed, the mass flow rate increases from 0.8 kg/s up to approximately 2 kg/s when the solar radiation varies between 200 W/m2 and 1000 W/m2 for fixed ambient temperature value of 30 °C. When ambient temperature increases from 10 °C up to 50 °C, the mass flow rate decreases slightly and in a linear manner from 1.7 kg/s to 1.5 kg/s for fixed solar radiation intensity value of 600 W/m2. Contrasting to other studies, conclusion based on simplified analytical models, ambient temperature affects adversely the performance of a SCPP in decreasing the mass flow rate. This conclusion should be taken into consideration when analyzing models dedicated to the prediction of solar chimney power plant performance.

Effect of Ambient Temperature on the Performance of PVT System in Bangladesh

The ambient temperature has a significant impact on PVT effectiveness. In this study, the effect of ambient temperature on PVT system under specific operating conditions in Bangladesh is investigated numerically. Using the FEM, a mathematical model of a three-dimensional PVT system is taken into account and resolved. Based on Bangladesh's weather, a range of 10 to 40 degrees Celsius is chosen as the ambient temperature. It is investigated how ambient temperature affects the cell and output fluid temperatures, electrical power and thermal energy, electrical efficiency-thermal efficiency, and overall system efficiency. The calculations reveal that for every 10°C increase in ambient temperature, the cell and output water temperatures rise by 1.5°C and 0.04°C, respectively, while the electrical efficiency falls by around 0.1% and the thermal energy increases by 8.9 W.

Seasonal variation in the response of a monoecious crop to increased temperature and fertilizers.

Climate warming may affect the performance of plants directly through altering vegetative or reproductive traits, and indirectly through modifying interactions with their pollinators. On the other hand, the addition of fertilizers to the soil may increase the quantity and quality of floral rewards, favoring the visitation of pollinators and, consequently, the reproductive success of plants. However, it is still unknown whether fertilizers may counteract the effects of increased temperature on the vegetative, floral, and reproductive traits of plants, as well as on the interaction with their pollinators. The aim of this study is to evaluate the effects of the input of organic and synthetic fertilizers on several vegetative and floral traits, and on the rate of legitimate floral visitors and reproductive success of the squash during two seasons, under a scenario of an increase in ambient temperature. During the dry and the rainy seasons, three vegetative, eleven floral, and two reproductive traits, as well as the duration of visits and visitation rate of legitimate floral visitors were evaluated in squash plants distributed into six treatments in a bifactorial design: temperature (ambient or elevated temperature) and fertilizer (organic, synthetic or without supplementary fertilizers). Contrary to our predictions, we found that an increase of ~1.5°C in ambient temperature, positively influenced several vegetative, floral, and reproductive traits in this crop, and that organic fertilizers, in general, was not better than synthetic fertilizers in improving those traits. Interestingly, the response of the squash and indirectly on their legitimate floral visitors to the increase of temperature and the input of fertilizers vary widely among seasons, suggesting great temporal variation in plant-pollinator responses to temperature and nutrient availability, which makes food security more unpredictable.

Performance analysis of liquid-based battery thermal management system for Electric Vehicles during discharge under drive cycles

The performance of an Electric Vehicle (EV) is determined by the battery pack's specific power, specific energy, self-discharging rate, and cycle life. However, these parameters are sensitive to temperature. Therefore, thermal management is the most critical factor defining a battery pack's performance in an EV. Even though thermal management of lithium-ion batteries has received a lot of attention, there has been minimal research on the performance of liquid based battery thermal management systems for Electric Vehicles for the actual drive cycles like the Indian drive Cycle and Federal Test Procedure (FTP-75) drive cycle. This study investigates the thermal behaviour of the Li-ion battery pack of an EV and the performance of a liquid-based battery thermal management system with various coolant options, such as Water, Water-Ethylene Glycol mixture, and Water-Propylene glycol mixture for both Indian Drive Cycle and FTP-75 (Federal Test Procedure) Drive Cycle. The numerical simulation is carried out for a battery pack with four modules, and liquid-based battery thermal management is designed at the pack level, considering the heat generated in the battery pack. The variation of battery pack temperature and cumulative energy consumption by the battery thermal management system (BTMS) is also investigated. The simulation model is designed in such a way that it tries to maintain a set battery pack temperature of 25 °C. Also, the effect of ambient temperature on the performance of the liquid cooling system has been analyzed. The results indicated that with the increase in ambient temperature the BTMS takes a longer time to cool the battery pack and cumulative energy consumption by the liquid based BTMS also increases for both the drive cycles. In the case of Water-Propylene glycol mixture, 25 % propylene glycol concentration is recommended, whereas in the case of Water-Ethylene glycol mixture, 50 % ethylene glycol concentration provides the best performance as both cumulative energy consumption by the battery thermal management system and temperature distribution in the battery pack are optimum.

Research of Property and Calibrate Method for Pressure Release Device of Power Transformer in the Grid

This paper introduces the types, internal structures and working principles of common non-electricity protection devices, and theoretically analyzes the cooperation between non-electricity protection devices. For pressure relief devices, the requirements of relevant standards for pressure relief valves are introduced, matters needing attention in field use of pressure relief valves are summarized, and factors affecting the performance of pressure relief valves are analyzed. Finally, using the calibration platform, through a large number of experiments, the influence of external environment temperature, caliber and pressure release times on pressure release performance parameters was studied. The results show that the average opening pressure at high temperature (95°C) is significantly lower than the average opening pressure of 10 times at normal temperature. At the same time, with the increase of ambient temperature, the aging opening pressure and the average opening pressure will obviously decrease, while the average closing pressure will increase. In addition, under normal temperature environment, the test values of aging opening pressure, average opening pressure and average closing pressure have little change. For pressure relief valves with different calibers, under the same rated opening pressure, the calibers of the pressure relief valves are different, which has little influence on the actual opening pressure. Through the research on the operation reliability of qualified pressure relief valves, it is found that the opening pressure after 50 operations and the first measured opening pressure and closing pressure data after 500 operations are relatively stable.

Increasing evapotranspiration decouples the positive correlation between vegetation cover and warming in the Tibetan plateau.

Plant growth generally responds positively to an increase in ambient temperature. Hence, most Earth system models project a continuous increase in vegetation cover in the future due to elevated temperatures. Over the last 40 years, a considerable warming trend has affected the alpine ecosystem across the Tibetan Plateau. However, we found vegetation growth in the moderately vegetated areas of the plateau were negatively related to the warming temperatures, thus resulting in a significant degradation of the vegetative cover (LAI: slope = −0.0026 per year, p < 0.05). The underlying mechanisms that caused the decoupling of the relationship between vegetation growth and warming in the region were elaborated with the analysis of water and energy variables in the ecosystem. Results indicate that high temperatures stimulated evapotranspiration and increased the water consumption of the ecosystem (with an influence coefficient of 0.34) in these degrading areas, significantly reducing water availability (with an influence coefficient of −0.68) and limiting vegetation growth. Moreover, the negative warming effect on vegetation was only observed in the moderately vegetated areas, as evapotranspiration there predominantly occupied a larger proportion of available water (compared to the wet and highly vegetated areas) and resulted in a greater increase in total water consumption in a warmer condition (compared to dry areas with lower levels of vegetation cover). These findings highlight the risk of vegetation degradation in semi-arid areas, with the degree of vulnerability depending on the level of vegetation cover. Furthermore, results demonstrate the central role of evapotranspiration in regulating water stress intensity on vegetation under elevated temperatures.

The Effect of The Inclusion of The Secondary Roof Under the Main Roof on Performance of Chimney Solar Power Plants

In this work the effect of the inclusion a second roof on the power output of chimney solar power plant (SCPP) were investigated numerically through analytical model. The analytical model presented in this work based on energy balance equations and mass conservation equation at steady state. In second step, the proposed analytical model is then used to estimate the annual electricity production in Sétif, a region of Algeria. For the position of the sun in Setif is 36.19 degrees longitude and 5.41 degrees latitude. It appears from results obtained that the efficiency is increased by 28.7 % for the chimney solar power plant (SCPP) with the secondary roof compared to chimney solar power plant (SCPP) without second roof. It was also concluded that there is an optimal height of the second roof for the power output of chimney solar power plant (SCPP) to remain maximum. It is noted that the energy production increases with the increase in radiation and ambient temperature. However, the solar irradiation is the dominant factor on the electricity production of the chimney solar power plant, compared to the ambient temperature. The results obtained are in good agreement with the experimental results of a prototype plant in MANAZANARES.

The potential of transcritical cycles based on CO[formula omitted] mixtures: An exergy-based analysis

This paper focuses on the thermodynamic comparison between pure supercritical Carbon Dioxide and blended transcritical Carbon Dioxide power cycles by means of a thorough exergy analysis, considering exergy efficiency, exergy destruction and efficiency losses from Carnot cycle as main figures of merit. A reference power plant based on a steam Rankine cycle and representative of the state-of-the-art (SoA) of Concentrated Solar Power (CSP) plants is selected as base-case. Two different temperatures of the energy (heat) source are considered: 575 °C (SoA) and 725 °C (next generation CSP).Compared to SoA Rankine cycles, CO2 blends enable cycle exergy efficiency gains up to 2.7 percentage points at 575 °C. At 725 °C, they outperform both SoA and pure CO2 cycles with exergy efficiencies up to 75.3%. This performance is brought by a significant reduction in the exergy destruction across the compression and heat rejection process rounding 50%. Additionally, it has been found that the internal condensation occurring inside the heat recuperator for those mixtures with a large temperature glide improves recuperator exergy efficiency, supporting the use of simpler layouts without split-compression. Finally, CO2 blends exhibit lower cycle exergy efficiency degradation than pure sCO2 in the event of an increase in the design ambient temperature.

Effects of land use on thermal enrichment of urban stormwater and potential mitigation of runoff temperature by watershed-scale stormwater control measures

Stream temperature is critical to the survival and reproduction of fauna in cold-water ecosystems. Urbanization causes abrupt increases in ambient stream temperature via stormwater inputs while concurrently decreasing groundwater recharge and stream baseflow. Relatively little is known about how various urban land uses affect thermal load discharged to streams or whether a network of green infrastructure retrofitted at the watershed scale can ameliorate these impacts. Runoff temperature and hydrology were monitored at 17 urban and two forested watershed outlets to assess 1) how urban land use affects stormwater thermal pollution and 2) if thermal pollution can be mitigated through infiltrating stormwater control measures (SCMs). Significantly and substantially larger runoff temperatures (i.e., event mean temperature, event maximum temperature) and thermal loads were observed from every urban land use (without SCMs) in comparison to forested (i.e., surrogate for pre-development) conditions. Event mean temperatures generally followed the land use trend of parking lot > light industrial > commercial > heavy industrial > multi-family residential, single family residential > low density residential > forest. Retrofitted bioretention cells and permeable pavements were not successful in mitigating runoff temperature in residential watersheds compared to (1) watersheds without SCMs or (2) restoring temperature to surrogate pre-development conditions. SCMs were seldomly able to mitigate enough runoff volume to have a significant thermal load reduction compared to watersheds without SCMs. These results suggest stormwater management and cold-water species management have not yet been successfully integrated. More work is needed to optimize green infrastructure SCMs design for sufficient treatment of runoff to protect cold-water ecosystems from urban development. Beyond SCM implementation, wholistic watershed management practices (e.g., riparian buffers, clustered imperviousness, underground storage/conveyance) are needed to stem thermal enrichment of streams and lakes by stormwater.

PHYTOCHROME-INTERACTING FACTOR 4/HEMERA-mediated thermosensory growth requires the Mediator subunit MED14.

While moderately elevated ambient temperatures do not trigger stress responses in plants, they do substantially stimulate the growth of specific organs through a process known as thermomorphogenesis. The basic helix-loop-helix transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) plays a central role in regulating thermomorphogenetic hypocotyl elongation in various plant species, including Arabidopsis (Arabidopsis thaliana). Although it is well known that PIF4 and its co-activator HEMERA (HMR) promote plant thermosensory growth by activating genes involved in the biosynthesis and signaling of the phytohormone auxin, the detailed molecular mechanism of such transcriptional activation is not clear. In this report, we investigated the role of the Mediator complex in the PIF4/HMR-mediated thermoresponsive gene expression. Through the characterization of various mutants of the Mediator complex, a tail subunit named MED14 was identified as an essential factor for thermomorphogenetic hypocotyl growth. MED14 was required for the thermal induction of PIF4 target genes but had a marginal effect on the levels of PIF4 and HMR. Further transcriptomic analyses confirmed that the expression of numerous PIF4/HMR-dependent, auxin-related genes required MED14 at warm temperatures. Moreover, PIF4 and HMR physically interacted with MED14 and both were indispensable for the association of MED14 with the promoters of these thermoresponsive genes. While PIF4 did not regulate MED14 levels, HMR was required for the transcript abundance of MED14. Taken together, these results unveil an important thermomorphogenetic mechanism, in which PIF4 and HMR recruit the Mediator complex to activate auxin-related growth-promoting genes when plants sense moderate increases in ambient temperature.

‘Bushfire Season’ in Australia: Determinants of Increases in Risk of Acute Coronary Syndromes and Takotsubo Syndrome

BackgroundClimate change has resulted in an increase in ambient temperatures during the summer months as well as an increase in risk of associated air pollution and of potentially disastrous bushfires throughout much of the world. The increasingly frequent combination of elevated summer temperatures and bushfires may be associated with acute increases in risks of cardiovascular events, but this relationship remains unstudied. We evaluated the individual and cumulative impacts of daily fluctuations in temperature, fine particulate matter of less than 2.5 µm (PM2.5) pollution and presence of bushfires on incidence of acute coronary syndromes and Takotsubo syndrome. MethodsFrom November 1, 2019, to February 28, 2020, all admissions with acute coronary syndromes or Takotsubo syndrome to South Australian tertiary public hospitals were evaluated. Univariate and combined associations were sought among each of 1) maximal daily temperature, 2) PM2.5 concentrations, and 3) presence of active bushfires within 200 km of the hospitals concerned. ResultsA total of 504 patients with acute coronary syndromes and 35 with Takotsubo syndrome were studied. In isolation, increasing temperature was associated (rs = 0.26, P = .005) with increased incidence of acute coronary syndromes, while there were similar, but nonsignificant correlations for PM2.5 and presence of bushfires. Combinations of all these risk factors were also associated with a doubling of risk of acute coronary syndromes. No significant associations were found for Takotsubo syndrome. ConclusionThe combination of high temperatures, presence of bushfires and associated elevation of atmospheric PM2.5 concentrations represents a substantially increased risk for precipitation of acute coronary syndromes; this risk should be factored into health care planning including public education and acute hospital preparedness.

Development of a heat load index for grazing dairy cattle

ABSTRACT Many indices have been developed to predict heat stress in dairy cattle, but no indices exist specifically for extensively grazed dairy cattle where wind and solar radiation modify heat stress responses. Using a large database of respiration rates and matching weather data, we developed a Grazing Heat Load Index (HLI) to predict respiration rates in extensively grazed dairy cattle. The Grazing HLI includes ambient temperature, solar radiation, and wind speed for the hour immediately preceding the respiration rate measure and was more accurate at predicting respiration rates than existing temperature humidity indices. On average, we observed an increase of 4.21 breaths per minute per 1°C increase in ambient temperature, an increase of 5.89 breaths per minute per 1 megajoule/m2 increase in solar radiation and a reduction of 1.70 breaths per minute per 1 km/hr increase in wind speed. We observed marked changes in panting score and percentage of drooling animals at Grazing HLI of greater than 70. This maybe a threshold when dairy cattle welfare is seriously compromised due to heat, however, noting that respiration rate starts to increase more steeply before this threshold.

Performance investigation of a portable liquid cooling garment using thermoelectric cooling

• The temperature of the hot end greatly affects the cooling effect. • A specific cooling temperature is proposed to evaluate the overall cooling performance. • 70% of the cooling effect decline comes from worse heat dissipation at the hot side. Liquid cooling garment (LCG) have been developed to reduce heat stress and improve human thermal comfort in hot environments. In this study, a novel thermoelectric LCG was developed to improve the portability and cooling performance of cooling garments. A specific cooling temperature was proposed to assess the overall cooling performance of the LCG and its value is 6.6 ℃/kg, which is a significant improvement over the previous cooling garment. The LCG is tested by using human trial to study the effect of ambient temperature and the temperature of the hot side of the cooling unit on the cooling performance of the cooling garments. The research results show that both the ambient temperature and the temperature of the hot side of the cooling unit will have an inhibitory effect on the cooling performance of the LCG. In addition, the contribution percentage of the worse heat dissipation from the hot side of the semiconductor chilling plate to the environment ( E G ) and the heating of the region surrounding the sensors ( E H ) to the decrease in the cooling effect of the LCG was determined. The experimental results show that the E G value is maintained at about 70% in different ranges of ambient temperature, which indicates that when the ambient temperature increases, the main factor leading to the declines of the cooling performance of the LCG is the worse heat dissipation at the hot side of the cooling unit. The E H value is about 30%, which shows that it is necessary to consider the heating of the region surrounding the sensor to reduce the error of testing the cooling performance of the cooling garment. The results of this paper can provide direction and basis for further improving the cooling performance of thermoelectric LCG, and can significantly improve the accuracy of the cooling performance test results in the future.

Cadmium removal from wastewater by foamed magnetic solid waste-based sulfoaluminate composite biochar: Preparation, performance, and mechanism

Conventional magnetic biochar presents disadvantages such as fragility and high cost of imparting magnetic properties, and its fragility leads to the risk of free dispersion and low recovery rate in field applications. To solve these problems, sulfoaluminate cement was used as cementitious material, mixed with natural magnetite and biochar, and combined with foaming technology to prepare a new granular adsorbent in this work. The adsorbent exhibited excellent properties with compressive strength (1000 mN), specific surface area (49.32 m2 g−1), and magnetic properties (13.95 emu g−1). The adsorption capacity for Cd2+ was 45.94 mg g−1 at 25 °C, and it increased with the increase of ambient temperature. The adsorption mechanism was mainly dominated by the chemical interactions of monolayer adsorption, including coordination and complexation between Cd2+ and surface functional groups (e.g. –COO–Cd, –O–Cd), Cd–π interactions on aromatic structures, and the precipitation mechanism (Cd(OH)2, CdCO3).

Dielectric and energy storage properties of all-organic sandwich-structured films used for high-temperature film capacitors

Dielectric polymers with ultrahigh power density are widely utilized in the fields of modern electronics and power systems. This article proposes the all-organic sandwich-structured films with ferroelectric polymer poly (vinylidene fluoride-hexafluoropropylene) and linear polymer poly (ethylene terephthalate) (PET) as the energy storage dielectrics for film capacitors. The morphological characterizations, thermal, dielectric, and energy storage performances have been investigated to evaluate the comprehensive properties of the sandwich-structured films. Excellent interlaminar interfaces are observed between poly(vinylidene fluoride-hexafluoropropylene) and PET layers. Compared with pure PET films, the sandwich-structured films exhibit improved thermal stability and dielectric constant, but some degradation in loss factor and breakdown strength. With the increase of ambient temperature, the sandwich-structured films still show improved and stable dielectric properties and insulating strength up to 125 °C. The sandwiched all-organic film shows an improved energy density (Ud) as high as 8.2 J/cm3 and concurrently an immense charge-discharge efficiency of 86.4%. This strategy offers a feasible idea to enhance the thermal, dielectric, and energy storage capability of dielectric films with a layered architecture, which facilitates the evolution of flexible film capacitors.

Sleep disruption induces activation of inflammation and heightens risk for infectious disease: Role of impairments in thermoregulation and elevated ambient temperature

ABSTRACT Thermoregulation and sleep are tightly coordinated, with evidence that impairments in thermoregulation as well as increases in ambient temperature increase the risk of sleep disturbance. As a period of rest and low demand for metabolic resources, sleep functions to support host responses to prior immunological challenges. In addition by priming the innate immune response, sleep prepares the body for injury or infection which might occur the following day. However when sleep is disrupted, this phasic organization between nocturnal sleep and the immune system becomes misaligned, cellular and genomic markers of inflammation are activated, and increases of proinflammatory cytokines shift from the nighttime to the day. Moreover, when sleep disturbance is perpetuated due to thermal factors such as elevated ambient temperature, the beneficial crosstalk between sleep and immune system becomes further imbalanced. Elevations in proinflammatory cytokines have reciprocal effects and induce sleep fragmentation with decreases in sleep efficiency, decreases in deep sleep, and increases in rapid eye movement sleep, further fomenting inflammation and inflammatory disease risk. Under these conditions, sleep disturbance has additional potent effects to decrease adaptive immune response, impair vaccine responses, and increase vulnerability to infectious disease. Behavioral interventions effectively treat insomnia and reverse systemic and cellular inflammation. Further, insomnia treatment redirects the misaligned inflammatory- and adaptive immune transcriptional profiles with the potential to mitigate risk of inflammation-related cardiovascular, neurodegenerative, and mental health diseases, as well as susceptibility to infectious disease.

Molecular Markers Associated with Heat Tolerance in Wheat

High temperatures have emerged as a major significant barrier for wheat production, which is generally adapted to the high temperature and sub-tropical environment. The sensitivity of wheat to high temperature a very high mainly during the grain filling stages due to the vulnerability of abiotic stresses. In the tropical and sub-tropical regions, each increase in ambient temperature can lower grain yield by 3-20%. Tolerance to high temperature is a complicated phenomenon and a quantitative trait that influences a variety of physiological and agronomic traits. No single trait thoroughly explains why certain wheat varieties can produce higher yield even when exposed to heat stress. Genes and molecular markers associated with stress tolerance mechanisms are crucial for improving crop productivity under high temperature environment. Different genotypes respond differently to heat stress, and this is mediated by genes or quantitative trait loci (QTL). Genotypes that are either high temperature stress resistant or mature early without yield loss, allowing them to avoid stress are needed to be produced. Plant breeders should concentrate on current yield patterns and environmental stress, as well as traits related to yield stability and sustainability. To increase the possibility of success of new methods like DNA marker technology will be needed despite the persistent yield enhancement from conventional breeding

Water Losses in the Condenser Cooling System at the 905 MWe Power Unit

The paper focuses on water losses in the turbine condenser cooling system of the 905 MW power unit in Opole Power Plant (Opole Poland). The evaporative and drift losses are determined for various operating and atmospheric conditions. The drift loss is found to be 0.125–0.375% of the cooling water flux and some increase in this loss is noticed with increase in unit power and ambient temperature. The studies have shown that the presence of wind increases the total water loss related to the power generated by the power unit. This effect is analysed for selected constant air temperature values Tamb. The increase of the cooling water loss stream, related to the power of the unit, is at the level of 14.8% for Tamb equal to 7 °C, 23% for 15 °C, and approximately 10% at 22 °C. These increases are related to the level of losses in almost no wind conditions. It is investigated how the change in the cooling water flux affects the power unit operation and the amount of water loss. For the power unit under consideration, the reduction of the cooling water flux from 80,000 to 60,000 ton/h raises the temperature of water behind the condenser and lowers the temperature of the cooled water tw2 within the range of 0.75–1.5 °C, depending on the unit power and the ambient temperature. Reducing the cooling water flux in the analysed range results in an increase in condenser vapour pressure, within 0.5 kPa at Tamb = 25 °C. This increase is lower at lower ambient temperatures. Within the range of variations analysed, the effect of cooling water flux on evaporative losses is negligibly small. The increase in condenser steam pressure significantly affects the power generated by the turbine generator unit. The calculations show that it is possible to optimize the size of the cooling water flux for the analysed power unit and condenser cooling system. This optimization would allow (within a limited range of load variability) an increase in the net power generated by the power unit.