Performance characteristics of the HYCSOS chemical heat pump system based on rare earth transition metal AB5 hydrides

The Argonne HYCSOS system is a chemical heat pump based on rare earth-transition metal AB5 hydrides that functions in heating, cooling, and energy conversion modes. Hydrogen gas is transferred from one hydride bed by thermal energy input at a characteristic temperature to a second bed where hydrogen is absorbed and thermal energy is released at another characteristic temperature. The two materials used in the present system are LaNi5 and CaNi5. The demonstration unit has four hydride containing steel tanks of three liter capacity each with internal heat transfer tubing. Three fluid heat transfer loops which can be remotely valved and fluid pumped into the appropriate tank are available. The thermal energy input, solar or other suitable low temperature heat, is simulated by an 18 KW electric heater. A 25 KW water cooled heat exchanger is used for heat rejection. Hydrogen and heat transfer fluid flows and temperature and heater and pump power are measured and recorded on a data logger. Important data are visually displayed on analog readout meters on a graphic panel. For safety considerations, the hydrogen containing subassembly is contained in an enclosed hood provided with continuous hydrogen concentration monitoring. The unit is of sufficient size that thermal losses are small compared to measured heat transfer rates in a heat storage mode, refrigeration mode and power generation mode. Experimental data will be compared with predicted performance