A solar desalination plant containing separate chambers for evaporation and condensation with air heating after the condenser. Part 1: Calculating distiller capacity

The effect of climatologic conditions and reservoir releases on downstream conditions was determined by means of statistical and graphical analyses of stream-temperature variations measured in the upper Delaware River basin, May-September 1964-67. Climatologic conditions normally increase water temperatures from February through July and decrease them from August through January. Summer releases from New York City's Cannonsville Reservoir were observed to decrease water temperatures by 13?C (Celsius) in 8.1 miles and by 1?C, 55.9 miles downstream from this reservoir. Releases from New York City's Pepacton Reservoir were observed to decrease water temperatures by 11?C in 31.0 miles and between 1?-3?C in 71.0 miles downstream from this reservoir. The influence of releases from these reservoirs is dependent upon five factors: thermal stratification in the reservoir, depth at which water is withdrawn from the reservoir, rate of release, distance downstream from the reservoir, and climatologic conditions.

A concept for improving the physical and technical indices of solar desalination by means of forced convection is studied. Dependence of physical dimensions of the condenser from the ambient parameters, cooled air temperature and its velocity are calculated.

Upon apnoeic face immersion, humans develop a diving response resembling that found in diving mammals. There have been contradictory reports regarding the influence of water temperature on the magnitude of the resulting bradycardia. This study examined the influence of both water and ambient air temperatures on human diving bradycardia. A group of 23 volunteers performed three series of apnoeic episodes after 60 min exposure to air at temperatures of 10, 20 or 30 degrees C. Oral and skin temperatures were measured during this exposure and during the subsequent test on 5 subjects. At 20 degrees C air temperature oral and skin temperatures were measured on 10 subjects. Heart rate (HR) was recorded for the 23 subjects during apnoea in air and apnoea with the face immersed in water of 10, 20 or 30 degrees C, at each air temperature. We found that both air and water temperatures had significant effects on immersion bradycardia, but in opposite directions. Face immersion in cold water after exposure to a high ambient air temperature induced the most pronounced bradycardia. We further observed that exposure to different ambient air temperatures resulted in different patterns of HR response to water temperature. The range in which the response was positively correlated to water temperature differed at 30 degrees C ambient air from that at 10 and 20 degrees C ambient air. We concluded from these studies that human bradycardia resulting from apnoeic face immersion is inversely proportional to water temperature within a range which is determined by the ambient air temperature. Thus, the interval in which the response to cold stimulation varies with temperature, would appear to be determined by the ambient temperature before stimulation.

Performance evaluation of a solar multi-stage humidification dehumidification desalination plant with heat recovery section

Studies predicting how the distribution of aquatic organisms will shift with climate change often use projected increases in air temperature or water temperature. However, the assumed correlations between water temperature change and air temperature change can be problematic, especially for mountainous, high elevation streams. Using stream fish assemblage data from 1,442 surveys across a mountain-plains gradient (Wyoming, USA; 1990-2018), we compared the responsiveness of thermal guilds, native status groups, and assemblage structure to projected climate warming from generalized air temperature models and stream-specific water temperature models. Air temperature models consistently predicted greater range shift differences between warm-water and cold-water species, with air temperatures predicting greater increases in occurrence and greater range expansions for warm-water species. The "over-prediction" of warm-water species expansions resulted in air temperature models predicting higher rates of novel species combinations, greater increases in local species richness, and higher magnitudes of biotic homogenization compared with water temperature models. Despite differences in model predictions for warm-water species, both air and water temperature models predicted that three cold-water species would exhibit similar decreases in occurrence (decline of 1.0% and 1.8% of sites per 1°C warming, respectively) and similar range contractions (16.6 and 21.5 m elevation loss per 1°C warming, respectively). The "over-prediction" for warm-water species is partially attributable to water temperatures warming at slower rates than air temperatures because local, stream-scale factors (e.g., riparian cover, groundwater inputs) buffer high elevation streams from rising air temperatures. Our study provides the first comparison of how inferences about climate-induced biotic change at the species- and assemblage-levels differ when modeling with generalized air temperatures versus stream-specific water temperatures. We recommend that future studies use stream-specific water temperature models, especially for mountainous, high elevation streams, to avoid the "over-prediction" of biotic changes observed from air temperature variables.

Near-surface bulk water temperature measured in large northern lakes during the warm season with buoys can be characterized by three components: a slowly varying seasonal-/climate-related trend, fluctuations at the time scale of weather perturbations, and rapid daily fluctuations. When thermal infrared data are used to estimate surface water temperature, an additional term relating the differences between the skin and bulk temperatures is implied. Buoy data in this work serve to demonstrate the existence of a period of strong signal coupling between fluctuations of water temperature and air temperature. The period of strong signal coupling does not extend beyond the date of maximum temperature in the water temperature trend. During this period, a simple linear transformation of air temperature fluctuations can be used to simulate the buoy water temperature fluctuations. Attempts to simulate water temperature fluctuations from air temperature alone are not possible beyond this period. Water temperature simulation error depends on the distance of the air temperature measurement from the buoy, ranging from ±1.1°C at 0 km to ±1.4°C at 40 km. The method developed with buoy data is applied to the combination of satellite thermal infrared and operationally measured air temperature data to simulate water temperatures. Through the use of satellite data, the water temperature simulations are extended beyond the period of strong coupling.

Diel temperature signals track seasonal shifts in localized groundwater contributions to headwater streamflow generation at network scale

Safe drinking water for the coastal areas of Bangladesh has become a big challenge. Arsenic adulteration and salinity intrusion in surface water body has accelerated the scarcity of water in the coastal region. As situation ameliorating and also investment for water-borne diseases is decreasing, it becomes the major threat for a third-world country like Bangladesh. There are lots of alternatives for water supply but there are also a huge number of constraints. Most of the traditional dug wells (DW), ring wells (RW) and alternative pond sand filters (PSF) are now inoperative due to shortage of fresh surface water body and also adequate maintenance. Except a few, most of the shallow tube wells (STW) and deep tube wells (DTW) in coastal areas face arsenic (As) contamination. There could be a blended solution for these problems based on existing situation, constraint, hydrogeology and individual’s economy. Different kinds of filters, reverse osmosis (RO), solar desalination plants (low-cost and small scale) and fuel-powered desalination plants (high-cost and large scale), etc., would be a good solution for mitigation of these problems. Solar PSF and rain water harvesting (RWH) might be an effective solution for some areas, respectively where fresh water and rainfall is abundant. Keywords: Arsenic contamination, salinity intrusion, climate change, pond sand filter, rain water harvesting, desalination, natural disaster

Constructal design of distributed energy systems: Solar power and water desalination

To predict climate-induced change in aquatic environments, it is necessary to understand the thermal constraints of various fish species and to understand the timing of current and projected coastal temperatures. This paper presents a newly developed model of the relationship between air and water temperature that was constructed on the basis of harmonic analysis. The model is novel because it requires only a single variable (air temperature) to predict water temperature and captures the hysteresis patterns of the rising and falling limbs and their historic memories. The model was calibrated and validated with data collected from monitoring buoys in Mikawa Bay, Japan between 2005 and 2009. The model validation showed a good performance with a root mean squared error (RMSE) in the range of 0.8–1.0°C. It is especially encouraging that the suggested model can predict water temperature with a reasonable level of accuracy once an acceptable relationship between air temperature and water temperature has been constructed from previously measured data.

Solar desalination: A review of recent developments in environmental, regulatory and economic issues

Changes in water temperature impact the dynamics of lake ecosystems. Changing climate factors, including wind speed and air temperature, influence the water temperature of lakes. This research aims to analyze the response of water temperature to wind speed and air temperature in Lake Laut Tawar. Observations were conducted from August to September 2023, with a sampling frequency of every two weeks. The results revealed that water temperature, wind speed, and air temperature in Lake Laut Tawar fluctuated according to the presence of light, namely day and night factors. Variations in sunlight intensity lead to hourly fluctuations in air temperatures, while wind speeds vary hourly due to changes in air pressure, consequently resulting in hourly variations in water temperature as well. During daylight hours, air temperature surpasses water temperature, whereas during nighttime hours, water temperature exceeds air temperature. Heat transfer from the air to the water contributes to an increase in water temperature, while the release of heat energy from the surface water into the air leads to a decrease in water temperature. Changes in the water temperature of Lake Laut Tawar are primarily influenced by changes in wind speed and air temperature by 80 percent simultaneously. However, while air temperature showed a partial response, wind speed did not exhibit a significant response. The relationship between these variables can be expressed through a mathematical model Tw = 0.356 Ta + 0.025 W + 15.674, where Tw is water temperature (°C), Ta is air temperature (°C), and W is wind speed (km/minute). Another factor that influences the water temperature of Lake Laut Tawar is the inlet water temperature, which was not observed in this research.

Thermal regime has a critical impact on the lotic environment, as maximum temperature determines the boundaries of the occurrence of aquatic species, seasonal and diurnal water temperature variations affect their bioenergetics, while the timing of specific water temperature values during the year is important in the context of spawning and migrations. However, despite the great importance of water temperature studies in the context of environmental management and fisheries, as well as the development of accurate measurement techniques, such investigations have received relatively limited attention in Poland. The current study attempted to examine the seasonal differentiation of water temperature in lowland rivers. For this purpose, water temperature was recorded from the 1st of May 2015 to the 30th of April 2019 with a temporal resolution of 30-minutes. Digital temperature reorders used to make the measurements were distributed across six sites in Jeziorka, Świder and Utrata catchments located on the Mazovian Lowland and the Southern Podlachia Lowland near Warsaw. The hydrometeorological background of the water temperature monitoring was determined on the basis of data from the Warszawa-Okęcie station and water gauging stations. On the basis of the measurement data, mean, maximum, and minimum monthly water temperatures were calculated and presented on the background of the appropriate air temperature data, while statistical distribution of the 30-minute water temperature, aggregated in a monthly timescale, was presented on the box and whiskers plots. The Ward method was used to group months similar in terms of their thermal conditions, while the Pearson correlation coefficient was applied to evaluate the strength of the relationship between water and air temperature. The results indicate that the seasonal course of water temperature follows the course of air temperature, with the highest mean monthly water temperatures recorded in July, while the lowest in January. Statistical distribution analysis of water temperature in individual months and its grouping by the Ward method allowed to identify two periods characterized by relatively stable thermal conditions and two periods of dynamic changes of water temperature. In contrast to the maximum values of water temperature, which were observed in the summer as a result of intensive solar radiation and low streamflow rates, the greatest variability of water temperature, as indicated by reference to mean daily range and standard deviation, was found in the spring months, i.e. in April and May, while the lowest in winter, from December to February. The relationship between daily mean water temperature and air temperature, established with the use of the Pearson correlation coefficient on a monthly basis, was clearly stronger during the spring increase and the autumn fall of the water temperature, which can be linked with greater vulnerability to atmospheric heat fluxes. A definitely weaker relationship was found in the winter and summer months, when greater importance can be attached to other drivers of stream temperature, like the presence of ice cover, cloudiness, riparian shading, and groundwater inflows.

Acquiring in situ water temperature data is an indispensable and important component for analyzing thermal dynamics in estuarine and coastal areas. However, the long-term and high-density monitoring of water temperature is costly and technically challenging. In this paper, we present the design, calibration, and application of the smart temperature sensor TS-V1, a low-power yet low-cost temperature sensor for monitoring the spatial–temporal variations of surface water temperatures and air temperatures in estuarine and coastal areas. The temperature output of the TS-V1 sensor was calibrated against the Fluke-1551A sensor developed in the United States and the CTD-Diver sensor developed in the Netherlands. The results show that the accuracy of the TS-V1 sensor is 0.08 °C, while sensitivity tests suggest that the TS-V1 sensor (comprising a titanium alloy shell with a thermal conductivity of 7.6 W/(m °C)) is approximately 0.31~0.54 s/°C slower than the CTD-Diver sensor (zirconia shell with thermal conductivity of 3 W/(m °C)) in measuring water temperatures but 6.92~10.12 s/°C faster than the CTD-Diver sensor in measuring air temperatures. In addition, the price of the proposed TS-V1 sensor is only approximately 1 and 0.3 times as much as the established commercial sensors, respectively. The TS-V1 sensor was used to collect surface water temperature and air temperature in the western part of the Pearl River Estuary from July 2022 to September 2022. These data wells captured water and air temperature changes, frequency distributions, and temperature characteristics. Our sensor is, thus, particularly useful for the study of thermal dynamics in estuarine and coastal areas.

This paper examines the numerical analysis of the transient analysis of solar desalination and the effect of climatic conditions on its performance. The solar water desalination plant is intended to convert the salt water of the seas and lakes into fresh water. TRNSYS software is used for simulation. In order to study the effect of weather conditions on the efficiency of solar water desalination, the cities of Bandar Abbas, Bushehr, Isfahan, Hamedan, Kerman, Mashhad, Tabriz, Zahedan and Tehran have been considered. The effect of solar collector area and auxiliary heater power on solar water desalination efficiency has been investigated. The results show that with increasing collector area and auxiliary heater power, the outlet water temperature of the collector increases. Carbon dioxide production has decreased by about 4.5-8.6% compared to diesel desalination. Using the analytic hierarchy process decision-making algorithm, the best location for installing the desalination plant has been selected based on the two criteria of solar water desalination efficiency and distance from the sea. Bushehr city is in the first place with 75% efficiency and Tabriz city is in the second place with 61% efficiency.