World Wide Assets LLC
Sustainable Development
Volumetrics
The following concerns the most recent testing of the unit in January of 2007.
The final modification testing was done to eliminate the final variable possible with this prototype. The single variable left is the temperature of the chill water. At the CalEnergy Demonstration facility we will have the capability to test a full size Delta T unit and sufficient chill water at the correct temperature to fully test the unit using geothermal energy. (This contract was signed by SDSU in early May 2007. SDSU will do several studies about the project and the use of geothermal energy for desalination.)
Final testing of the unit, as is, without augmenting the temperatures or benefiting from numerous small thermodynamic efficiencies the full size unit provides indicated a volume output of 0.44 acre feet per day.
The limited energy available at SDSU created a problem in testing various configurations as the prototypes developed.
As is normal in prototyping, each development shaped the investigation and future modifications and designs. As the prototypes developed and configurations changed, it became readily apparent that the limiting factors would indeed be the available chill water from the SDSU Physical Plant Department.
As is true in all scientific investigations, limiting the number of variables reduces the probability of errors in the test results. A separate flow model was developed that is applicable to the vertical multi-phase fluid flows (water and air flows) which considered the hysteresis at multiple phases and thermodynamics to conserve mass, inertia, momentum, and energy exchanges within the unit to emulate different controlled entropy configurations with minimal physical alterations of the pilot plant system.
Closure relationships expected and specified for the interfacial friction factor of vertical flows and expected coefficients of expansion throughout the hysteresis of the hot and cold water as well as the thermodynamic relationships and volumes of gas transfer velocities under these circumstances and the implications when applied to the demonstration unit entrainment rates were carefully considered in their relationship to the data points before each prototype/ modification/ emulation operation began.
Although a separate flow model allowed previous emulations at 1:20 the use of that data was limited because of the thermal and volumetric limitations of that emulation model. However, it did reduce several variables, the water and air flows were patterned to emulate a unit that was 12’x1’x8’ in size. This configuration increased the water production to be more in line with the predictive formula of 2002.
That emulation testing failed to fully represent a corresponding full size unit because of two test parameters, namely, entrainment temperature and volume of the chill water, however, the data was in agreement with the 2002 predictive math model and supported the companies expectations of productivity at these variables in temperature and volumes.
Subsequently, several variables were discussed and a 1/40th emulation designed with various test variables needed to produce data at various flows. This emulation replicates a unit that is 1/40th the size of a production unit. In this emulation, a unit 6” deep and 8’ wide is emulated.
The unique feature of this emulation model is the ability to achieve parity of flows, even without reaching the temperature goals of the demonstration unit and calibrate the data against an array of two phase pressure and heat transfer data conditions. This unit accurately depicts 1/40th of the final design for the production size unit and reduces the variables to 2, those being 1) the unit length and 2) the temperature of the chill water.
The length can be adequately adjusted for numerically since there is no design difference, no fluid flow differences, merely extensions of the existing components, it is merely a matter of projecting the data to that size (usually by simple multiplication), however, the temperature is somewhat different in that the more extreme the temperatures curves the more exponential the water production is. This is to our benefit, and the reason for the demonstration plant, to wit, the elimination of these two variables.
For those projections we ignore several variables which will enhance the final production numbers such as enhanced thermodynamics due to reduced surface to operations space ratios, reduced heat loss from designed insulation not used on the demonstration or the pilot, enhanced fluid flows by gravimetrically enhanced air flows and their subsequent increases in carrier gas momentum and the cascade of beneficial effects this causes, exponential increases expected from thermodynamic models from the increased thermal flows of the demonstration unit, and so forth.
The first test run tested in the 1:40th emulation configuration had reduced hot water which was entrained at 50% of the true volume. This is done to test the vapor pressure and the Delta T of the chill water at those flows. The volumetrics surprised the company indicating good dehydration potential and high vapor pressure at these volumes. Though the chill water was thermally stable, again, we were more than 10F above the temperature expected at the demonstration project and for production. The hot water was thermally stable, but, again, only close to that of an operating plant. In a fully operational plant, the temperature gain will enhance the outcome.
Again we had a situation where the predictive model was sufficiently supported by empirical correlations.
The second test was conducted on the unit testing at water flow parity, which is expected in a fully operating unit. The company believed that the flow model developed would again be a reliable predictive tool to relate to a production model within the limitations experienced at SDSU.
A reliable prediction of flows and associated heat transfer rates and thermal coefficients is needed to project the data as a cost effective method of supporting the predictive math model of 2002 and creating flow models to conserve available geothermal energy not only at the CalEnergy demonstration, but also in fully operational desalination plants.
The Delta T process experiences both compressible and incompressible fluid flows, continual entrainment of annular and globular liquid/vapor interface exchange condensation units, and cyclical non-uniform pressure gradients which are motive forces which move carrier gas and vapor, entrainment sheeting as a liquid/vapor interface exchange evaporation enhancement device, and multiple horizontal flow apertures for rapid carrier gas exchange enabling gas movement from the condensation chambers to the evaporation chamber, all of which relate directly to the flow model design for the various emulations created.
The internal fluid flows are influenced by many system wide variables such as the exact geometry of the device, the designed flow orientations, and fluid flow velocities of water and carrier gasses.
This data supports the predictive model and provides sufficient demonstrable proof of the projected volumetric outcomes of the production size unit and more than justifies the predicted 163,000gpd volumes of that unit. In fact, the most recent data from our tests indicate that a decrease in temperature at the demonstration plant of -15F would result in a production rate of 0.6 to 0.68afd. We are, of course using 0.5afd (1/2afd) as the standard.
The data clearly shows a Delta T of 30 created a flow of 70gpm. Increasing the Delta T to 39 degrees increases the flow to 100gpm. We need 113.4gpm from a full size unit to reach the goal of 0.5afd.
Again, at 79gpm we are at 0.44afd, a phenomenal achievement and financially speaking, well within profit margins for any investor.
If we project this increase in a linear path (thermodynamics tells us it will be exponential) another 9F Delta T would increase that flow to 130gpm. This is easily achieved with a decrease in temperature of 20F which will be achieved at the demonstration plant.
We would rather understate than overstate the production, however, so we will continue to claim the 0.5afd, nevertheless, we can now project 0.6 to 0.68afd per unit and, with the exponential benefits the added thermodynamic gradient will provide with colder chill water, we will, in all likelihood, prove a higher number still.
Contact Professor Newcomb to receive more information on those numbers. (See “Contact Us” in the navigation bar to the right.)