Flow Rate Estimation In Glandless Circulator Pumps - Influence Of Temperature And Water-Glycol Heat-Transfer Fluids
Abstract
Modern high efficiency glandless circulating pumps are widely used in heating and cooling applications. They are equipped with integrated control electronics that are able to detect the power consumption and speed of the electric pump drive. By processing this data with the specific performance characteristics of the pump, the control electronic can estimate its operating point and become a soft senor for pump head and volume flow. In this paper the functional principle, possibilities and limitations of the flow estimation are examined. A special focus is on the temperature influence of pump media and the effects of water-glycol heat-transfer fluids. Influencing factors are discussed and, based on a typical circulator pump, uncertainties of the flow rate estimation are determined experimentally