Research Data: Report to Happy Bird Corporation on
Predicted Water Temperatures in the new Solar Sipper (Model 10040)
I have been developing a mathematical model of the thermal performance of solar sippers under various weather conditions. I have also been monitoring the temperatures of solar sippers during winter conditions on the front steps of my house on a number of days. Comparisons of performance of the "old" and "new" sippers have been made as well as predictions as to "How cold can it get before the water in the sippers freezes?" I wish to summarize the results of these measurements and analyses. The methodology of
the study briefly was:
It is important to
point out that the thermal performance of the sipper in reality is a function
of many variables. Specifically, on any given day the following can affect
the temperature of the water:
Obviously, if I systematically varied all of the above parameters to find the combinations predicted to result in no freezing of water, the number of such combinations would be very large and difficult to apply for a customer. Even though I have simplified the simulation to keep the results straightforward, it is important to keep in mind the limitations of the results described below. In the simulations, I kept all weather conditions as on the day I measured the actual sipper water temperature (i.e. a clear February 6th near Boston with no measurable wind near the sippers) and varied only the ambient temperature until the simulated water temperature reached 32 F. The simulated initial water temperature was 63 F, but the results were independent of the initial water temperature. For the "old" sipper {Model 10008) with a constant simulated ambient temperature of 20F, no freezing took place during daylight hours. For the "new" HDPE sipper (Model 10040), the constant ambient temperature could go down to 14 F. Constant ambient temperatures during the daylight hours are of course very rare and therefore not too realistic. Consequently, I searched a weather database for some recorded hourly weather data to use with the simulation model. The database is called WYEC2, and is available from the National Renewable Energy Laboratory in Golden, CO, and is made up of actual historical weather records with different months from different years pieced together to represent a typical meteorological year. I found the coldest day of the year for Boston (a relatively clear January 12th) and entered the ambient temperatures for the day and adjusted the model clear sky solar irradiation to match the daily total irradiation on the horizontal in the database. The average ambient temperature during the daylight hours varied from 7 F to 18 F and averaged 13 F. The new HDPE solar sipper (Model 10040) water did not freeze during daylight hours. (back to top)
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