Performance of compressors in high-temperature refrigeration?
Performance Characteristics Under High-Temperature Operating Conditions
Refrigerant Compatibility: The compressor uses the environmentally friendly refrigerant R407C, which exhibits good thermodynamic performance under high-temperature conditions. R407C is a blended refrigerant composed of R32, R125, and R134a in specific proportions, featuring a relatively high critical temperature, making it suitable for operation at elevated condensing temperatures.
Operating Temperature Range: Hitachi compressors are typically designed for an evaporation temperature range of -15°C to 12°C, with a condensing temperature capability of up to 43°C or higher. Under high-temperature refrigeration conditions, the compressor's discharge temperature will increase accordingly. However, with rational design, stable operation can still be maintained. Protective Measures in High-Temperature Environments
Discharge Temperature Control: The compressor is equipped with a PTC temperature sensor directly inserted into the discharge chamber to monitor the discharge temperature in real time. It automatically shuts down for protection when the temperature becomes excessively high. It also includes high and low-pressure protection devices to prevent pressure abnormalities caused by high temperatures.
Motor Protection: It incorporates a PTC motor protector from the German company KRIWAN, along with a delay circuit that ensures the compressor cannot restart until 5 minutes after shutdown, effectively safeguarding the motor's operation under high temperatures. Performance Under High-Temperature Operating Conditions
Energy Efficiency Performance: Under high-temperature refrigeration conditions, the compressor's COP value may decrease but can still maintain relatively high operational efficiency. Due to the slow suction and compression processes of scroll compressors, gas flow losses are minimal, resulting in high isentropic efficiency in both air conditioning and heat pump applications.
Reliability: Hitachi compressors utilize a high-pressure cylinder design, with extremely minimal gas leakage between the high and low-pressure zones. Combined with a forced lubrication system, they ensure long-term stable operation even under high-temperature conditions. Usage Recommendations
Ambient Temperature Control: The compressor's ambient temperature should not exceed 43°C, and the crankcase oil temperature should be kept below 80°C to ensure stable lubricant performance.
Regular Maintenance: Maintenance should be intensified under high-temperature conditions, including regular checks of condenser cleanliness and refrigerant pressure to ensure effective system heat dissipation.
System Matching: In high-temperature refrigeration applications, ensure the condenser is appropriately sized with adequate heat dissipation capacity to prevent the compressor from operating under prolonged overload conditions.
Overall, the G603DH-90D1 compressor demonstrates good adaptability and reliability under high-temperature refrigeration conditions. However, proper system design and enhanced maintenance are essential to ensure its long-term stable operation.
