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Results for “ARID raceway”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

ARID Raceway Temperature Model Evaluation

The ARID (Algae Raceway Integrated Design) raceway temperature model, written in Visual Basic for Applications, calculates algae culture temperature in ARID and conventional raceways as a function of meteorological data from agricultural weather stations. The model is an atmospheric boundary layer model and uses energy balance terms from the Penman-Monteith equation. The original model used evapotranspiration, as calculated by the weather station, and assumed an average daily albedo. In this research, equations for albedo and for direct calculation of evaporation from atmospheric parameters were added to the ARID model. Albedo was calculated with the Fresnel equations. The Penman-Monteith model was adjusted for algae raceway evaporation rather than reference evapotranspiration. The new model components were calibrated with data from a 21-day algae growth experiment in the ARID raceway during winter 2011. The model was also adapted to model variable circulation times and heat transfer through a canal cover. In summary, this research improved and calibrated the ARID temperature model for future use.

09 BIOMASS FUELS↗
DOE OSTI2014

Study of the flow mixing in a novel ARID raceway for algae production

A novel flow field for algae raceways has been proposed, which is fundamentally different from traditional paddlewheel-driven raceways. To reduce freezing and heat loss in the raceway during cold time, the water is drained to a deep storage canal. The ground bed of the new raceway has a low slope so that water, lifted by propeller pump, can flow down in laterally-laid serpentine channels, relying on gravitational force. The flow rate of water is controlled so that it can overflow the lateral channel walls and mix with the main flow in the next lower channel, which thus creates a better mixing. In order to optimize the design parameters of the new flow field, methods including flow visualization, local point velocity measurement, and CFD analysis were employed to investigate the flow mixing features. Different combinations of channel geometries and water velocities were evaluated. An optimized flow field design and details of flow mixing are presented. The study offers an innovative design for large scale algae growth raceways which is of significance to the algae and biofuel industry.

09 BIOMASS FUELS↗
DOE OSTI2015

Energy Productivity of the High Velocity Algae Raceway Integrated Design (ARID-HV)

The ARID raceway is an effective method to maintain temperature in the optimal growing range. However, the energy input is excessive. Thus, the ARID-HV raceway was developed in order to reduce energy input requirements. This was accomplished by improving pumping efficiency and using a serpentine flow pattern in which the water flows through channels instead of over barriers. A prototype ARID-HV raceway was installed in Tucson, Arizona in order to evaluate the flow and energy requirements of the raceway. Preliminary results show continued high energy usage, but this paper explores the possible energy reductions with the new ARID-HV design with efficient propeller pumps and properly engineered channel lengths. Channel lengths are evaluated with Manning’s equation in order to determine the maximum channel length that could be implemented with the current pumping configuration

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Association of Vampirovibrio chlorellavorus with decline and death of Chlorella sorokiniana in outdoor reactors

The outdoor ARID raceway was established for optimizing the cultivation of microalgae for biofuel production. During the summers of 2014 and 2015, discoloration was observed in cultures of Chlorella sorokiniana , which shifted from a vibrant green color to yellow, followed by cell clumping, decline in density, and rapid death, resulting in 40–60% reduced biomass production. To investigate, total DNA was purified from the raceway samples and subjected to polymerase chain reaction (PCR) amplification using degenerate primers that amplify the 16S rRNA gene of eubacteria. BLASTn analysis of the cloned amplicon sequences revealed the presence of the Gram-negative, predatory bacterium, Vampirovibrio chlorellavorus . Scanning electron microscopic examination showed an abundance of coccoid cells, 0.3–0.6 μm in diameter, some of which were attached to C. sorokiniana cells. PCR amplification indicated the presence of V. chlorellavorus in raceway vessels, water lines, connective tubing, and in early, scaled-up DOE1412 cultures used to inoculate the raceway. Based on PCR detection, the decontamination of the equipment and water line with "Wal-Clean" more effectively eliminated V. chlorellavorus and delayed the onset of attack, compared to the chlorine disinfectant, trichloromelamine (TCM). Total DNA was isolated from soil samples collected monthly from the nearby Rillito River during 2014–2015 and subjected to PCR amplification using primers designed to amplify the 16S rRNA and 18S rRNA gene of V. chlorellavorus and C. sorokiniana , respectively. Results indicated that V. chlorellavorus and Chlorella spp. were present in most of the riverbed samples nearly year round, suggesting a possible naturally occurring reservoir of the predatory bacterium.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Incorporation of salinity, nitrogen, and shading stress factors into the Huesemann Algae Biomass Growth model

The Huesemann Algae Biomass Growth (HABG) model predicts microalgae biomass growth in outdoor raceways as a function of water temperature and incident light intensity. The model over-predicted growth in several Regional Algal Feedstock Testbed (RAFT) experiments. Inspection of the culture conditions suggested that salinity stress, nutrient limitation, and shading reduced growth, which were not included in the original model. Laboratory experiments were carried out to measure growth response of S. obliquus to high salinity and limited nitrogen. In addition, the shading effect was estimated based on raceway geometry, solar angle, albedo and measured light intensity data. In this study, the improvement of model performance is presented step by step as each growth limiting factor is incorporated into the model. The new salinity, shanding, and nutrient stress factors remove most of the over-prediction of the original model. Comparison of the model with observed data indicated that ignoring the lag phase also resulted in overprediction. Delaying the start of the simulation until the end of the lag phase and inclusion of stress factors lowered model inaccuracy from 90% over-prediction to within ±10% in six out of seven batches.

09 BIOMASS FUELS↗
DOE OSTI2021

A Novel Platform for Algal Biomass Production Using Cellulosic Mixotrophy (CeMix) (Final Technical Report)

This novel project, branded CeMIX for cellulosic mixotrophy, targets solutions for several technological barriers limiting the deployment of algae cultivation in sunny, arid regions (specifically the southwest United States). Opening up the region for algae cultivation could increase DOE’s resource assessments and biofuel potential for the U.S. Mixotrophic metabolism in support of liquid fuel production is completely dependent on the availability of waste organic carbon in order to avoid diversion of food resources for fuel production. The use of cellulosic sugar hydrolysate (CSH) produced via the NREL process provided a standardized carbon source for study of the underlying biochemistry and metabolic adjustments to mixotrophy. Mixotrophic metabolism uses both photosynthetic CO 2 fixation and sugar oxidation to improve biomass productivity and harvest yield. The project was high-risk, high-reward in the sense that adding organic carbon to algal cultivation is an invitation for rapid-growth, heterotrophic contaminants to overtake the culture and consume mineral nutrients needed for algal growth. To help evade this outcome the project focused on acidophilic red algae that require low pH conditions with 40-48°C optimal temperature profiles that define them as low-range thermophiles. This is the only project in the BETO portfolio to utilize extreme conditions of low pH and high operating temperatures to control pathogens and competitors in mass culture. The project yielded five major outcomes. 1) Harvest densities of 5-10 g ash-free dry weight are easily achieved, providing a 10-fold reduction in water required and dewatering demand. 2) Catabolic repression of photosynthesis in G. sulphuraria is conditionally repressed by low oxygen. 3) Mixotrophic growth on cellulosic hydrolysate consumes all C6 and C5 sugars concomitant with increases in floridean starch with little change in lipid content. Protein content can be manipulated between 35 and 54 wt% by varying the C:N molar ratio from 10:1 to 20:1, respectively. 4) Mixotrophic cultures with up to 50 mM total sugar are remarkably stable at pH 2.5 and daily average reactor temperatures of 40°C. 5) Capital costs for glass tubular photobioreactors are prohibitive for liquid fuel production using a hydrothermal liquefaction processing pathway. The economic outlook for covered raceway ponds is better with a project minimum fuel selling price at $3.32 dm 3 GE -1 .

09 BIOMASS FUELS↗