Calorimetry is conceptually simple but considerable effort is required to reduce systematic errors to acceptable levels. Since 1989, we have designed and constructed a dozen calorimeter systems for cold fusion research. Each of these systems provided valuable experience in error detection and correction. The culmination of our efforts, an instrument with a design accuracy of 0.1% relative, is nicknamed MOAC (Mother Of All Calorimeters).
MOAC operates on a simple and fundamental principle. Flowing water is used to extract the heat from the cell. The flow rate is measured and the temperature rise of the water is measured. The product of the temperature rise, the flow rate, and the specific heat of water yields the heat power being extracted from the cell. Despite its simple concept, MOAC is not a simple instrument. Two independent computer-based data acquisition systems monitor a total of 45 parameters, including 22 temperatures. Fourteen analog outputs, driven by proportional-derivative feedback algorithms, control various critical parameters. The cell and heat exchanger are located in a chamber whose walls are made almost perfectly insulating by a system that heats the outer surface of each of the six wall panels so that its temperature matches that of the corresponding inner surface. This active insulation ensures that virtually all of the heat dissipated by the cell leaves the chamber via the flowing water. A cascade of three independent Peltier regulators controls the temperature of the water entering the heat exchanger to +/- 0.0003°C. A positive-displacement pump driven by a synchronous motor powered by a crystal-based oscillator produces an exceedingly stable flow of about 2.5 gm/s. A flowmeter consisting of an automated batch weighing system measures the flow rate periodically and typically reports a standard deviation of only +/-0.0002 gm/s (i.e. 0.01% relative). A large well-insulated enclosure houses the entire system. Air circulates over the calorimetry apparatus and then is ducted to a Peltier air-conditioner where its temperature is regulated to +/- 0.001°C before it re-enters the enclosure.
MOAC was designed to achieve +/- 0.1% relative accuracy. At the typical input power level of 10 watts, that is equivalent to +/- 0.01 watts. On a good day, when freshly calibrated, this accuracy is actually achieved. A month after calibration, the system typically drifts by up to 0.03 watts. We believe this drift originates primarily in the thermistors used to measure inlet and outlet water temperatures. Despite this small problem, we feel that MOAC is one of the best calorimeters now available for cold fusion research. The space available for the cell is relatively large (about 10 cm x 25 cm x 25 cm). The cell sits in a stirred air environment where it is not thermally clamped to a specific temperature. MOAC exhibits excellent specimen versatility by producing precisely the same reading regardless of the size, shape, or location of the heat source. We are committed to maintaining MOAC in top working condition on a continuous basis. In the interest of scientific progress, we have made a standing offer for free testing of promising cold fusion cells in MOAC.
The links on the left hand side contain all of the information published in a paper entitled “MOAC – A High Accuracy Calorimeter for Cold Fusion Studies,” an abridged version of which was published in the Proceedings of the 14th International Conference on Condensed Matter Nuclear Physics. To read the full version in PDF format, download it here.