Kg Of Water Research Articles

Energy, environmental and economic analyses of an indirect cocoa bean solar dryer: A comparison between natural and forced convections

The objective of the research is to present, the numerical simulation modelling of cocoa bean dryer in natural, forced and combined forced and natural convection to predict their effectiveness in a tropical environment. Cost analysis and CO2 mitigation potential of the solar dryer were also presented. The finite difference and fourth-order Runge Kutta method were used to resolve the iterative equations. The drying kinetics, drying rates, CO2 emissions mitigation, thermal efficiency and payback period are estimated in Yaoundé climate in Cameroon. It was difficult to have the moisture content of the product in equilibrium with ambient air using only natural convection. The best mode of functioning is to use forced convection during sunny period and natural convection during not sunny period. With an initial moisture content of 1.2 kg/kg (db), it took 32 h of drying time to obtained final moisture content of 0.15 kg/kg (db) using forced convection during the day and natural convection during the night for each month. The gradients of humidity and temperature are sufficient to have a homogeneous drying in the established product layers. The specific energy consumption range between 5 and 15 kWh per kg of humidity extracted for the combined natural and forced convection. The thermal efficiency of the solar collector is above 30%, while the global thermal efficiency ranges from 5% to 18%. The CO2 emissions mitigation potential per mass of evaporated water ranged between 15 and 25 g of CO2 per kg of water evaporated in a day. The calculated payback period was 2.19 years.

Experimental Performance Analysis of a Pilot-Scale Biomass-Assisted Recirculating Mixed-Flow Dryer for Drying Paddy.

A large amount of heat energy is required for paddy drying processes to evaporate water from paddy grains. Currently, fossil fuels are being used as an energy source to heat air during the drying process. However, fossil fuels cause air pollution, climate change, and disruption of ecological balance. In this study, to reduce the dependence on fossil fuels for paddy drying, a pilot-scale biomass-assisted recirculating mixed-flow drying system (PSBA-RMFD) for drying paddy was designed, installed, and tested. In this PSBA-RMFD, the heat energy required for heating the drying air was provided only by biomass. The PSBA-RMFD comprises a biomass furnace, drying column, vibratory feeder, bucket elevator, and blower. This study is aimed at evaluating the performance of the PSBA-RMFD with a drying capacity of 400 kg/h. The performance metrics of the PSBA-RMFD were specific energy consumption (SEC), specific thermal energy consumption (STEC), specific moisture evaporation rate (SMER), thermal efficiency of the PSBA-RMFD, exergy efficiency of the drying section, and improvement potential of the dryer. From the experiments conducted in this study, the values of the aforementioned performance parameters were as follows: 0.806-8.656 kW h/kg of water evaporated; 0.385-4.136 kW h/kg of water evaporated; 0.122-1.308 kg of water evaporated/kW h; 7.82-83.99%; 15.28-25.64%; and 858.90-1355.62 W, respectively. The paddy moisture content was reduced from 20.90% wet basis (initial weight of 400 kg) to 13.30% wet basis (final weight of 364 kg) in 270 min, with an average temperature of 78.15°C and average relative humidity of 8.55%. The percentage of biomass energy used in the drying system was approximately 47.77% of the overall energy. In addition, the payback period of the PSBA-RMFD was 1.9 years.

ТЕОРЕТИЧНЕ ДОСЛІДЖЕННЯ МОЖЛИВОСТІ ВИРОБНИЦТВА ТЕПЛОВОЇ ЕНЕРГІЇ ЗА ДОПОМОГОЮ ВІТРОМЕХАНІЧНИХ УСТАНОВОК

A widespread use of wind turbines can fully or partly provide energy for the consumers, but with due regards to certain investments and instability of energy generation. Technologies of using wind energy imply the conversion of the mechanical energy of a wind flow into the electrical or heat energy. The work is concerned with the estimation of the amount of heat in the process of heating liquid coolants and heat-transfer fluids when using wind mechanical plants. In the paper was made a numerical analysis of the temperature rise of the liquid which circulates in a closed loop of a gear-type pump, whose productivity is 3 l/m and which is driven by a wind turbine 5 kW of power capacity under a nominal wind speed of 7 m/s and under cycle duration of 2 s. The analysis showed that the temperature increased by 0.290 °К/s. If such wind speed is observed during one hour, the temperature of 100 kg of water will increase by 8.1°С. Heating of a heat-transfer fluid with a supply of mechanical energy to a working part can be achieved by a centrifugal fan. Assuming that the given process occurs without supplying and removing heat energy (it is adiabatic), for the capacity of 1.5 kW and under the revolution in a range of 1000….3000 r/m, the changes in temperature will range from 0.38 to 0.87 °К/s, but for the capacity of 7.5 kW and under 750 – 1500 r/m, the changes in temperature will range from 0.56 to 1.23 °К/s.

Performance evaluation of a rotary dryer in both co-current and counter-current configurations

A mathematical model was developed to simulate the process of superphosphates fertilizers drying in a rotary dryer in both co-current and counter-current configurations. Besides, the performance of the rotary dryer, installed in a local industrial unit, was assessed using the concept of energy and exergy analysis. Matlab software was used to develop the mathematical model, which is based mainly on mass and energy conservation equations. Good agreement between the simulated results and the experimental results from literature was obtained. The simulation results showed that the product’s moisture content was reduced from an initial value of 0,14 kgH2O / kg dry solid to 0.0912 and 0.0862 kgH2O / kg dry solid at the dryer's outlet for the co-current and the counter-current configurations, respectively. A parametric study was carried out to evaluate the effect of the length of the dryer and the inlet drying air temperature on the moisture content to compare both configurations. Energetic and exergetic indicators were formulated and then computed based on the inlet operating conditions. The energy efficiency and the specific energy consumption for the co-current and the counter-current configurations were, respectively, found to be 13% and 24% and 5762 and 3502 kJ per kg of water evaporated. The exergy indicators, namely the exergy loss, the exergy destruction rate, and the exergetic efficiency, were 11.37 and 17.82 kW, 1.026 and 1.098 kW, 25.86 and 41.38% for the co-current and the counter-current configuration, respectively. A sensitivity analysis was used to investigate the effect of varying the inlet drying air temperature on energetic and exergetic performance parameters.

Production and storage stability of concentrated micellar casein

Concentrated micellar casein (CMC) is a high-protein ingredient that can be used in process cheese product formulations. The objectives of this study were to develop a process to produce CMC and to evaluate the effect of sodium chloride and sodium citrate on its storage stability. Skim milk was pasteurized at 76°C for 16 s and cooled to ≤4°C. The skim milk was heated to 50°C using a plate heat exchanger and microfiltered with a graded permeability (GP) ceramic microfiltration (MF) membrane system (0.1 μm) in a continuous feed-and-bleed mode (flux of 71.43 L/m2 per hour) using a 3× concentration factor (CF) to produce a 3× MF retentate. Subsequently, the retentate of the first stage was diluted 2× with soft water (2 kg of water: 1 kg of retentate) and again MF at 50°C using a 3× CF. The retentate of the second stage was then cooled to 4°C and stored overnight. The following day, the retentate was heated to 63°C and MF in a recirculation mode until the total solids (TS) reached approximately 22% (wt/wt). Subsequently, the MF system temperature was increased to 74°C and MF until the permeate flux was <3 L/m2 per hour. The CMC was then divided into 3 aliquots (approximately 10 kg each) at 74°C. The first portion was a control, whereas 1% of sodium chloride was added to the second portion (T1), and 1% of sodium chloride plus 1% of sodium citrate were added to the third portion (T2). The CMC retentates were transferred hot to sterilized vials and stored at 4°C. This trial was repeated 3 times using separate lots of skim milk. The CMC at d 0 (immediately after manufacturing) contained 25.41% TS, 21.65% true protein (TP), 0.09% nonprotein nitrogen (NPN), and 0.55% noncasein nitrogen (NCN). Mean total aerobic bacterial counts (TBC) in control, T1, and T2 at d 0 were 2.6, 2.5, and 2.8 log cfu/mL, respectively. The level of proteolysis (NCN and NPN values) increased with increasing TBC during 60 d of storage at 4°C. This study determined that CMC with >25% TS and >95% casein as percentage of TP can be manufactured using GP MF ceramic membranes and could be stored up to 60 d at 4°C. The effects of the small increase in NCN and NPN, as well as the addition of sodium chloride or sodium citrate in CMC during 60 d of storage on process cheese characteristics, will be evaluated in subsequent studies.

Dyeing Properties of Polyester/Cotton Blended Fabric in the Silicone Non-Aqueous Dyeing System

Polyester/cotton blended fabrics have been extensively used in the textile industry. However, the dyeing process of polyester/ cotton blended fabrics is complex, and a large amount of water is consumed. To increase the dye uptake and dye fixation ratio, and reduce wastewater effluents, the dyeing performance of polyester/cotton blended fabric was studied in one bath and two steps using the silicone non-aqueous dyeing system. When dyeing 1 kg of polyester/cotton blended fabric, only 1.17 kg of water was consumed, and no wastewater was discharged after dyeing. The washing fastness, staining fastness, and dry and wet rubbing fastness of dyed fabric can reach high levels. The dyeing performance of two disperse dyes on the cotton and polyester components in the blended fabric was also studied.

Influence of the addition of water to total mixed rations on the feeding behaviour, feed intake and milk performance of high-yielding dairy cows

The goal of this study was to investigate the influence of the addition of water to total mixed rations (TMR) with a dry matter (DM) content of 42 - 47% and high proportions of ensiled forage on feeding behaviour, DM intake (DMI) and milk performance, as well as changes in TMR temperature. The underlying hypothesis was a reduction in the selective feeding behaviour and a resulting increase in DMI of the cows, which were provided with a moist TMR. During two feeding trials, 48 German Holstein cows per trial were split into 2 groups (Trial I, winter: 85 ± 28 d in milk (DIM); Trial II, summer: 67 ± 34 DIM). Both trials were set up as a crossover design with period lengths of 45 (Trial I) and 35 (Trial II) d. The rations in each trial were made of the same components, had the same energy and nutrient concentrations and had slightly different DM contents. In Trial I, a TMR with 46.4% DM (dry TMR) was mixed with 12.5 kg water per cow per day, to reduce the DM content of the TMR to 37.3% DM (wet TMR). In Trial II, the DM content of 41.8% (dry TMR) was reduced to 33.9% (Wet TMR) after 14 kg of water per cow per day were added. The DMI of the individual animals and their milk yield were measured daily, and the milk composition was determined weekly. To judge the feeding behaviour, samples were taken from each feeding group at five points throughout the day during Trial I, and three during Trial II. The samples were tested for particle size distribution using a Penn State Particle Separator (PSPS). In both trials, the selective feeding behaviour was reduced as a consequence of the addition of water to TMR. In the case of the dry TMR, a change in particle size distribution in the troughs was already discernible 10 h after the feed was provided. In both trials, the addition of water had a positive influence on the DMI. In Trial I, the cows consumed 1.3 kg DM/d more as a consequence of the addition of water (p < 0.001), and in Trial II the difference equated to 0.6 kg DM/d after the addition of water (p < 0.001). The increased energy and nutrient intake of the cows that had been fed with the moistened TMR led to higher daily milk yield (Trial I: +0.6 kg/d; Trial II: +0.5 kg/d) and drinking water intake (p < 0.001). During the first 24 h after mixing the rations in Trial II (summer), no temperature differences were observed between the dry and moistened TMR. During the time period of 24–48 h after feeding, the dry TMR had an average temperature of 36.8 °C and the wet TMR had a temperature of 40.1 °C, which was a significant difference (p < 0.001). Furthermore, in Trial II, the increased energy and nutrient intake was reflected in a higher fat and protein yield and in an increased energy-corrected milk yield by 0.8 kg/d (p = 0.015). These results confirm that by adding water to TMR, selective feeding behaviour can be reduced and DMI increased, both during summer and winter trials. The importance of a uniform, non-selective feed intake in high-performing dairy cows is also evident from the results.

Multi-effect evaporator desalination powered by geo-solar thermal energy

The abundance of solar energy in Saudi Arabia makes it the most promising option for use in water desalination. A salinity gradient solar pond (SGSP) is one of the most encouraging direct solar heat collectors. Increasing the gradient zone depth of the SGSP to 0.6m allows it to sustain the low operating temperature of single-or multi-effect evaporators (MEE) for 9 months of the year. The unique innovation of utilizing the heat of deep well water to support the operation of a system with such a low operating temperature provides feed water at up to 55°C, which means only 11.2kJ of heat energy is required to heat each 1kg of water to the MEE’s evaporation temperature. This is 9.7% of the energy required when using surface seawater. A MATLAB simulation tool was developed to model the coupling of an SGSP with an MEE and was validated with experimental data collected for the climatic conditions of Saudi Arabia. It is well known that a conventional thermal desalination plant is cost-intensive, but the coupling model study of SGSP–MEE shows its operational feasibility at much lower costs.

Development of an Easy-to-Operate Underwater Raman System for Deep-Sea Cold Seep and Hydrothermal Vent In Situ Detection.

As a powerful in situ detection technique, Raman spectroscopy is becoming a popular underwater investigation method, especially in deep-sea research. In this paper, an easy-to-operate underwater Raman system with a compact design and competitive sensitivity is introduced. All the components, including the optical module and the electronic module, were packaged in an L362 × Φ172 mm titanium capsule with a weight of 20 kg in the air (about 12 kg in water). By optimising the laser coupling mode and focusing lens parameters, a competitive sensitivity was achieved with the detection limit of SO42− being 0.7 mmol/L. The first sea trial was carried out with the aid of a 3000 m grade remotely operated vehicle (ROV) “FCV3000” in October 2018. Over 20,000 spectra were captured from the targets interested, including methane hydrate, clamshell in the area of cold seep, and bacterial mats around a hydrothermal vent, with a maximum depth of 1038 m. A Raman peak at 2592 cm−1 was found in the methane hydrate spectra, which revealed the presence of hydrogen sulfide in the seeping gas. In addition, we also found sulfur in the bacterial mats, confirming the involvement of micro-organisms in the sulfur cycle in the hydrothermal field. It is expected that the system can be developed as a universal deep-sea survey and detection equipment in the near future.

Design, manufacture and test of a low-cost solar cooker with high-performance light-concentrating lens

Solar radiation can be considered as one of the most suitable energy source to be used for cooking food. It is therefore important to promote advancement in solar cooking systems, in particular as concerns their efficiency and cooking times. In this work, we designed, realized and tested a novel low-cost solar cooker that uses a high-performance light-concentrating Fresnel lens, which is able to concentrate onto a small focal area a large amount of solar radiation. The radiation is then reflected by a mirror towards a cooking surface, where a pot can be located. The cooker has a geometrical concentration ratio of 40.97. In order to characterize the thermal performance of the cooker, we carried out several outdoor tests with a dedicated test setup, using water and silicone oil as absorbing media. Respect to other solar cookers, results show that the proposed cooker is able to reach high temperatures with good efficiency and reduced heating times: 3 kg of water can reach 90 °C in around 30 min, while 3 kg of silicone oil can be taken from 40 to 170 °C in less than one hour.

Life cycle assessment of processing for chrome tanned cowhide upper leather

Pollution has become a serious problem in leather industry, however, current method to evaluate its environmental effect usually used data from literature review, those data generated while leather manufacturing were rarely collected and analyzed. Thereby, the aim of this study was to evaluate the environmental effect of manufacturing process of chrome tanned cowhide upper leather by applying the Life Cycle Assessment protocols. Following the guidance of ISO 14010, we first combined data obtained from field study and empirical review; and then these data were input into eFootprint for calculation. Results, including four environmental indicators (global warming potential [GWP], primary energy demand [PED], water utility [WU] and acidification [AP]), show that producing 1 kg of cowhide upper leather releases 7.040 kg of CO2 eq, consumes 106.793 MJ of energy and 89.144 kg of water and emits 0.058 kg of SO2 eq. Sensitivity analysis of inventory data demonstrated that chrome tanning and retanning processes accounted for more than 40% of PED, AP and GWP, whereas the beamhouse was more than 78% of WU. Therefore, we could optimise the tanning process by using alternative materials or technologies in the critical sections to achieve cleaner production and sustainable leather manufacturing.

Physical Evolution of Solutions in Response to the Contact of Water with Beans: Case Study of Soaking and Boiling

The present paper aims to highlight the physical evolution of solutions from soaking and beans cooking process. This is motivated by the desire to shed light on the particular behavior of the bean end-of-cooking solutions when they are incorporated into the soil. For that purpose, solutions from soaking were produced by putting in contact 2kg of sorted and quickly washed beans seed with 8kg of water with known physical characteristics. Concerning the solutions from cooked beans, they were produced by putting on fire the pot containing the mixture of the water from soaking and bean seeds. The beans were a variety of Phaseolus vulgaris L.,known as “Meringue”. The cooking process was done without salts. The samples of solutions were collected as follow: 30 and 60 minutes respectively after the beginning of the soaking, 30, 60, and 90 minutes after the beginning of the cooking process of the beans soaked during 60 minutes. After each sampling, the equal volume of the solution collected was replaced with the water used for the cooking process. The color of the water used for the cooking process is translucent. Concerning solutions from soaking, their coloration are gradually reddish. Solutions from soaking and cooking process became abruptly dark red. From 60 minutes of the cooking process after soaking, the dark red coloration turn to strong brown. The solution handled in the case of the present study, from soaking and cooking the beans are gradually enriched in flakes compared to the situation noticed in the water used for the cooking process. But, the enrichment becomes abruptly high with the beginning of the cooking process after the process of soaking. In terms of consequence, their physical parameters studied in the present case study all increase in the same manner, notably the mass, the volumetric mass, and the density of the different solutions. The infiltration tests made including the water used for the different processes, solutions form the end of cooking the beans, and human urine show that the infiltration rate of the water from cooked beans is very low compared to that of the water used for the processes and human urine. The total infiltration of solution of the end of cooking the bean reveals on the infiltration surface the presence of a film of a matter bearing molds, generated by the progressive settling of this solution. The correlations established between the different parameters followed up here are highly positive. But in detail, the influence of an under laid parameter, known here as temperature, has been identified as being the responsible of the questioned behavior of the parameters taken in pairs in the case of correlation studies made. Finally, from this work, it emerges that the specific behavior of the bean end-of-cooking solution when it is introduced into the soil is justified by its progressive enrichment in organic matter during the cooking process.

Study on the effect of conical and parabolic solar concentrator designs on hybrid solar dryers for apricots under variable conditions: A numerical simulation approach

ABSTRACT The main objective of this paper is to present a numerical model and simulation of coupled heat and mass transfer of solar dryer with various solar concentrator shapes considering the thermo-physical properties of apricot and climatic conditions of Nancy France. The resolution of the model will permit the prediction of the temperature and humidity of the solar air heater at the collector and drying chamber and also determine the moisture profile during the drying process. The thermal performance of each concentrator design was compared for best performance. A solar dryer with a non-coaxial conical concentrator presented for drying of apricot under the variable external conditions was used for the validation of the model. The numerical results showed a good agreement with experimental data determined for Elazig town Turkey. Numerically the global results were satisfying for moisture content and air temperature for the solar dryers. Parabolic concentrator had comparatively poor drying kinetics when compared with conical concentrators while co-axial design outperforming the non-coaxial design for drying kinetics. When applied in Nancy France environment to dry 30 kg of apricot with an initial moisture content of 3.5 kg/kg (db), lower energy consumption of 8.143 MJ per kg of water removed was determined for non-hybrid drying with non-coaxial conical concentrator while intermittent deployment for 2 MW electrical power consumed more energy with the higher energy of 18.668 MJ per kg of water extracted. For simulation on the environmental condition of Nancy France under the winter, summer, autumn and spring periods drying kinetic were better for drying with 1 MW continuous drying, while drying with 2 MW discontinuous drying performed better in the autumn period. Generally, non – hybrid drying performed poorly compared to others but is more energy utilization efficient compared to others.

Energy, exergy and environmental impact analysis on the novel indirect solar dryer with fins inserted phase change material

Solar energy is a widely used green energy resource that is used for drying processes. Through this assessment, the performance of an Indirect Solar Dryer (ISD) with three different cases, namely solar collector - without Thermal Energy Storage (TES), with TES unit having Phase Change Material (PCM) and with TES having fins inserted PCM have been experimentally analyzed during spring and summer seasons for drying Momordica charantia. Totally six experiments were undertaken to compare temperature, drying kinetics, and energy analyses. The initial moisture level of 2 kg of specimen decreased from 1.84 kg of water (92% w. b) to 0.24 kg of water (12% w. b) in 10.5 h utilizing ISD with TES having fins inserted PCM (Test 6). The maximum thermal efficiency achieved about 19.41% on Test 6. Exergy efficiency increased from 8.66% to 79.02% at Test 6. Environmental impacts assessment has revealed that the Energy Payback Time for the ISD was 1.42 years. The CO2 emission, mitigation, and carbon credit gained (Test 6) are 23.88 kg/year, 20.13 tons, and $100.642 to $402.569 for the 35 years’ intended lifespan. The assessment report showed that the device established was a potentially effective commercial drying technique, both in energy utilization and environmental sustainability.

Drying of soybean grains with direct-fired furnace using wood chips: Performance, quality and polycyclic aromatic hydrocarbons

The search for new technologies and options of activities to improve agricultural production systems are goals continuously desired by companies. Thus, the objective of this study was to evaluate the performance of soybean grain drying, using a furnace dryer automatically fed with eucalyptus chips, the quality of the grains before and after drying, as well as contamination by polycyclic aromatic hydrocarbons (PAHs). Twenty-seven samples were collected before drying and 27 samples were collected after drying, totaling 54 samples of around 1.0 kg each, at 5-minute intervals. The following experimental evaluations were carried out: dryer – performance, calorific value and fuel consumption; grains – moisture content, germination, electrical conductivity, apparent specific mass, thousand-grain weight, color, oil acidity index and polycyclic aromatic hydrocarbons. The dryer showed an average efficiency of 75.61% for drying the grains. The average fuel consumption was 21.78 kg of chip per ton of dry grains. The specific energy consumption to remove 1.0 kg of water was 11,871.80 kJ. In general, drying did not compromise the final quality of soybeans. Soybeans showed the presence of two PAHs before drying and three more PAHs appeared after drying. Average concentrations were lower than the maximum values allowed by European Union Law No 835/2011. The drying conditions used for soybean grains influenced the low formation of PAHs.

Development of a Latent Heat Thermal Energy Storage Material-Based Refrigeration System

The present research focuses on application of thermal energy storage on a convectional refrigerator to enhance its performance. Salt hydrate was used as latent heat thermal energy storage (LHTES) material to convert the convectional refrigerator to a LHTES material-based refrigerator. The cabinet of the convectional refrigerator was loaded with 10 kg of water at a temperature of 28℃ and experiments were conducted on it to know the time taken for the evaporator temperature (TE) to reach -5℃, and determine the performance characteristics of the convectional refrigerator. The experiments were repeated on the LHTES material-based refrigerator to compare its performance characteristics with those of the convectional refrigerator. The results reveal that the evaporator of the LHTES material-based refrigerator attains the temperature of -5℃ forty minutes before the same temperature (-5℃) was attained in the evaporator of the convectional refrigerator. For the interval of evaporator temperature (−5∘C≤TE≤−1∘C) considered for evaluation of the performance characteristics of the refrigerators in this work, when TE drops from 1℃ to -5℃, the coefficient of performance (COP) for the LHTES material-based refrigerator and convectional refrigerator decreases from 7.36 to 4.62 and 6.44 to 4.15, respectively; the refrigerating effect decreases from 118.41 kJ/kg to 111.80 kJ/kg and 113.37 kJ/kg to 106.69 kJ/kg, respectively; the compressor work increases from 15.10 kJ/kg to 23.18 kJ/kg and 17.60 kJ/kg to 25.68 kJ/kg, respectively. The higher value of the COP and refrigerating effect, and the lower value of the compressor work of the LHTES material-based refrigerator compared with those of the convectional refrigerator imply that there is an improvement in the performance of the refrigerator with the LHTES material. The current work broadens research on the use of a LHTES materials to enhance the performance of a refrigerator.

Life cycle assessment of bacterial cellulose production

Bacterial cellulose (BC), obtained by fermentation, is an innovative and promising material with a broad spectrum of potential applications. Despite the increasing efforts towards its industrialization, a deeper understanding of the environmental impact related to the BC production process is still required. This work aimed at quantifying the environmental, health, and resource depletion impacts related to a production of BC. An attributional life cycle assessment (LCA) was applied to a process design of production of BC, by static culture, following a cradle-to-gate approach. The LCA was modeled with GaBi Pro Software using the ReCiPe 2016 (H) methodology with environmental impact indicators at midpoint level. The functional unit was defined as 1 kg of BC (dry mass), in 138.8 kg of water. From the total used resources (38.9 ton/kg of BC), water is the main one (36.1 ton/kg of BC), most of which (98%) is returned to fresh waters after treatment. The production of raw materials consumed 17.8 ton of water/kg of BC, 13.8 ton/kg of BC of which was for the production of carton packaging, culture medium raw materials, and sodium hydroxide (for the washing of BC). The remaining consumed water was mainly for the fermentation (3.9 ton/kg) and downstream process (7.7 ton/kg). From the identified potential environmental impacts, the production of raw materials had the highest impact, mainly on “Climate change”, “Fossil depletion”, “Human toxicity, non-cancer”, and “Terrestrial toxicity”. The sodium dihydrogen phosphate production, used in the culture medium, showed the highest environmental impacts in “Human toxicity, non-cancer” and “Terrestrial ecotoxicity”, followed by corn syrup and carton production. The static culture fermentation and downstream process showed impact in “Climate change” and “Fossil depletion”. Per se, the BC production process had a small contribution to the consumption of resources and environmental impact of the BC global life cycle.

Techno-economic comparison of selected solar dryers: A case study

The basic design of most commonly used solar dryers displaying varying fundamental principles of heat and mass transfer were compared with recently commercialized and patented design of Solar Conduction Dryer. Bottle gourd of 100 kg by mass, having an initial moisture content of 80% from which 77.78 kg of water was required to be removed to get the desired moisture content of about 10%, was used as drying load. The performance of various solar dryers were analyzed on the basis of three criteria, namely, the annualized cost, the present worth of annual savings, and the present worth of cumulative savings. The economic analysis shows that the present cumulative worth of annual savings for drying bottle gourd over the dryers lifetime works out to be 42,294, 23,027, 55,451, 58,740, and 37,594 USD for the case of solar tunnel dryer, solar cabinet dryer, solar conduction dryer, corrugated solar conduction dryer and corrugated and electrically backed solar conduction dryer, respectively. The economic parameters of interest, such as the payback period and the internal rate of return of dryers were also estimated. The analysis shows that the corrugated solar conduction dryer (CSCD) gives the best performance as compared to the rest of the solar dryers when compared on the basis of economics and product quality attributes.

Experimental Validation of the Thermal Processes Modeling in a Solar Still

Passive solar distillation is cheap and energy-efficient technology but its main disadvantage is low productivity. Thus, there are many attempts to improve solar stills’ productivity, and one of them is changing the mass of the water. This paper presents the results of validation of the thermal processes modeling in a solar still (SS). In order to validate the model, the experimental studies were conducted in a laboratory to ensure uniform climatic conditions. The studies were carried out for 10 kg, 15 kg, and 20 kg of water under three different solar irradiance conditions. The results show that 10 kg and 20 kg of water ensure the highest and the lowest daily productivity, respectively, independently of solar irradiance. When the water mass is 10 kg, the solar still’s productivity is 800 mL/m2/day, 3732 mL/m2/day, and 9392 mL/m2/day for low, medium, and high solar irradiance, respectively. Additionally, it is found that reducing the water mass from 20 kg to 10 kg can improve solar still’s productivity by a maximum value of 21.6%, which is obtained for low solar irradiance. The proposed mathematical model allows predicting the performance of the SS. The results of the theoretical calculations are in good agreement with the results of the experiments. The minimum and maximum deviation between the actual and theoretical productivity of the SS is 1.1% and 8.3%, respectively.

Short-term liveweight changes of dairy cows measured by stationary and walk-over weighing scales

Monitoring and detecting individual cows' liveweight (LW) and liveweight change (LWC) are important for estimation of nutritional requirements and health management, and could be useful to measure short-term feed intake, water consumption, defecation, and urination. Walk-over weighing (WOW) systems can facilitate measurements of LW for these purposes, providing automated LW recorded at different times of the day. We conducted a field study to (1) quantify the contribution of feed and water intake, as well as urine and feces excretions, to short-term LWC and (2) determine the feasibility of stationary and WOW scales to detect subtle changes in LW as a result of feed and water intake, urination, and defecation. In this experiment, 10 cows walked through a WOW system and then stood individually on a stationary scale collecting weights at 10 and 3.3 Hz, respectively. Cows were offered 4 kg of feed and 10 kg of water on the stationary scale. For each animal, LW before and after eating and drinking was then calculated using different approaches. Liveweight change was calculated as the difference between the initial and final LW before and after eating and drinking for each statistical measure. The weights of feed intake, water consumption, urination, and defecation were measured and used as predictors of LWC. Urine and feces were collected from individual cows while the cow was on the scale, using a container, and weighed separately. The agreement between LWC measured using either stationary or WOW scales was assessed to determine the sensitivity of the scales to detect subtle changes in LW using the coefficient of determination (R2), Lin's concordance correlation coefficient (CCC), and mean bias. The prediction model showed that most of the regression coefficients were not significantly different from +1.0 for feed and water, or -1.0 for urine and feces. The R2 and CCC values demonstrated a satisfactory agreement between calculated and stationary LWC and values ranged from 0.60 to 0.92 and 0.71 to 0.94, respectively. A moderate agreement was achieved between calculated and automated LWC with R2 and Lin's CCC values of 0.45 to 0.63 and 0.60 to 0.74, respectively. Therefore, results demonstrated that new algorithms and data processing methods need to be continuously explored and improved to obtain accurate measurements of LW to measure changes in LW, especially from WOW scales.