Method of monitoring refrigerant level

US7146819B2 · kind B2 · utility

Assignee

• Behr GmbH & Co. · DE

Inventors

• Walter Demuth · Gerlingen, DE
• Rainer Heilig · Philippsburg, DE
• Volker Kirschner · Rochlitz, DE
• Martin Kotsch · Ludwigsburg, DE
• Hans-Joachim Krauss · Stuttgart, DE
• Hagen Mittelstrass · Nagold, DE
• Harald Raiser · Balingen, DE
• Michael Sickelmann · Stuttgart, DE
• Karl-Heinz Staffa · Stuttgart, DE
• Christoph Walter · Stuttgart, DE

Key dates

• Filing date: Feb 10, 2004
• Grant date: Dec 12, 2006
• Expiry date: Apr 24, 2024

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F25B2700/21175
• WIPO field: Thermal processes and apparatus
• WIPO sector: Mechanical engineering

Abstract

The invention relates to a method of refrigerant level monitoring in a refrigerant circuit of an air-conditioning or heat-pump system having a compressor and a refrigerant which may, depending on the operating point, be operated in the supercritical range. The method includes standstill level monitoring with the compressor switched off and/or in-operation level monitoring with the compressor switched on. In the case of in-operation level monitoring, the refrigerant overheat (dTü) at the evaporator is registered and, in the event of excessive overheat, it is concluded that there is underfilling. At a standstill, the pressure and temperature of the refrigerant are registered, and it is concluded that there is an improper refrigerant filling level if the pressure (pKM) lies below a minimum pressure value (pmin) or the temperature (TKM) lies above a maximum saturation temperature value (TS) with the pressure being outside a predefinable intended pressure range ([pu,po]).