Brief Description of the Calorimetry in the Rossi Experiment at U. Bologna, January 14, 2011

by Jed Rothwell

The experiment has been underway at U. Bologna since mid-December 2010. It has been done several times. Several professors with expertise in related subjects such as calorimetry are involved.


A hydrogen tank mounted on a weight scale which is accurate to 0.1 g

10 liter tank reservoir, which is refilled as needed during the run

Displacement pump

Tube from pump to Rossi device (The Rossi device is known as an "ECat")

Outlet tube from the Rossi device, which emits hot water or steam

Thermocouples in the reservoir, ambient air and the outlet tube

An HD37AB1347 IAQ Monitor (Delta Ohm) to measure the relative humidity of the steam. This is to confirm that it is “dry steam”; that is, steam only, with no water droplets.

Alternating-current heater used to bring the Rossi device up the working temperature


The reservoir water temperature is measured at 13°C, ambient air at 23°C.

The heater is set to about 1000 W to heat up the Rossi device. Hydrogen is admitted to the Rossi device.

The displacement pump is turned on, injecting water into the Rossi device at 292 ml/min.

The water comes out as warm water at first, then as a mixture of steam and water, and finally after about 30 minutes, as dry steam. This is confirmed with the relative humidity meter.

As the device heats up, heater power is reduced to around 400 W.


The test run on January 14 lasted for 1 hour. After the first 30 minutes the outlet flow became dry steam. The enthalpy during this last 30 minutes can be computed very simply, based on the heat capacity of water (4.2 kJ/kgK) and heat of vaporization of water (2260 kJ/kg):

Mass of water 8.8 kg
Temperature change 87°C
Energy to bring water to 100°C: 87°C*4.2*8.8 kg = 3,216 kJ
Energy to vaporize 10 kg of water: 2260*8.8 = 19,888 kJ
Total: 23,107 kJ

Duration 30 minutes = 1800 seconds

Power 12,837 W, minus auxiliary power ~12 kW

There were two potential ways in which input power might have been measured incorrectly: heater power, and the hydrogen, which might have burned if air had been present in the cell.

The heater power was measured at 400 W. It could not have been much higher that this, because it is plugged into an ordinary wall outlet. Even if a wall socket could supply 12 kW, the heater electric wire would burn.

During the test runs the weight of the hydrogen tank did not measurably decrease, so less than 0.1 g of hydrogen was consumed. 0.1 g of hydrogen is 0.1 mole, which makes 0.05 mole of water. The heat of formation of water is 286 kJ/mole, so if the hydrogen had been burned it would have produced less than 14.3 kJ.

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