Our setup consisted of a beaker, magnetic stir bar, hotplate (for stirring, not heating), thermocouple, a ring stand to hold up the Davey Cell, the Davey cell and a power meter for AC appliances.
The procedure was simple; boil water with the Davey cell and compare the theoretical energy to the actual used energy. Below is a step by step of our procedure.
- fill beaker or wide plastic bowl with RO (reverse osmosis) water
- optional: put baking soda in the water
- weigh the water/container and magnetic stir bar
- insert the Davey heater into the bath
- plug Davey heater into the energy meter
- plug energy meter into wall outlet
- let boil for 10-30 min
- remove and unplug Davey heater from bath and wall
- record temp of stirred bath
- weigh remaining water, container and stir bar
- record metered power (device gives kWh, plugging the meter in starts the count and unplugging it stops the count)
- calculate theoretical power to boil water and heat up the bath
- compare for COP
Our results are in a single spreadsheet.
We did not see any excess heat. There was one instance where we calculated a COP of 1.1. We believe this was in error of our equipment (mainly the power meter, read to 0.01 kWh). The rest of the tests resulted in a COP of less than 1.
The Davey cell was certainly fun to play with and observe. You could clearly see the bubbles emerging from the space between the bells. The bubbling intensity varied with the concentration of baking soda. More baking soda, more violent bubbling.
This specific Davey cell created brass oxides in the water, these turned the water into a brown scummy mixture while the cell was active. Stainless steel could be used instead.
We played with adding baking soda a little. The more we added the better the electrical connection and the more power it drew from the wall outlet. As we added more baking soda, it got to a point where the Davey cell would continually trip the breaker. After that dilutions were made for the actual runs.
Hunt Utilities Group, LLC