EXPERIMENTAL ENTHALPIES AND DENSITIES OF COMPRESSED LIQUID REFRIGERANTS.
Conference Paper
Overview
Overview
abstract
We have investigated two refrigerant fluids, dichlorodifluoromethane (R-12) and chlorotrifluoromethane (R-13) using two new experimental apparatus that we developed to measure the enthalpies and densities of compressed liquid states. Our experiments were performed at temperatures between 230 and 475 K, and for pressures from the saturation curve to 70 MPa. One apparatus is a direct-weighing PVT measurement. A cell of known volume is suspended directly from an electronic balance, so that the mass of fluid in the cell can be determined directly as a function of temperature and pressure. The resulting densities are accurate to better than 0. 1% for samples with mass densities greater than 100 kg m** minus **3. The other apparatus is a flow calorimeter of unique design. The system uses a thermoelectric cooling element to remove energy from the calorimeter vessel at a precisely controlled rate. Energy is supplied to the vessel either by an electrical heater or by the sample fluid flowing through the system. The enthalpy of the fluid is measured by observing changes in the power delivered by the electrical heater required to maintain the calorimeter vessel at constant temperature. The enthalpies measured with this apparatus are considered to be accurate to better than 0. 3%.
