Features and advantages
Fast digital PID control
The introduction of new digital PID control stabilises the chilled/hot water temperature with high accuracy. It quickly responds to the load ﬂuctuation and supplies stable chilled/ hot water temperature. It is suitable for air-conditioning intelligent buildings which require sophisticated control.
Graph 5 - Hot water valve opening control
Variable (5-30 minutes) Example 15 minutes 30 minutes
Hot water consumption Hot water consumption (%) Hot water control opening ratio (%)
Saving energy with the inverter (option)
Balancing the load and ﬂow rate with the absorbent pump’s inverter control enables efﬁcient and energy-saving operation. As a result, it reduces input energy and electric power consumption. Running cost is decreased by 5% compared to non-inverter control.
Hot water control valve opening ratio Cooling water entering temp. Chilled water entering temp.
Graph 4 - Running cost curve
Chilled water leaving temp.
Energy consuption ratio (%) Non-inverter control
Expansion of safe operating zone
This ensures quick response to rapid changes and maintains stable operation. The safe operating zone is between 19 °C and 34 °C cooling water temperature (for a nominal cooling water entering temperature of 32 °C).
Graph 6 - Safe operating zone chart
Cooling load factor (%) Notes
1. 2. Chilled water leaving temperature 7°C constant Cooling water entering temperature:
Load factor (%) 100 50 30
Temperature (°C) 32 27 25
A microprocessor monitors the absorbent concentration. Steam supply is stopped, and the unit is returned to normal operation, when the concentration is over a certain limit, to prevent the crystallisation of absorbent
The high-performance purge system maintains the required operating pressure, preserves chiller performance characteristics, minimises chiller maintenance to one purge operation per season (for year-round operation).
Hot-water valve opening control
At the start-up, the opening angle of the hot-water control valve is controlled in three stages, reducing the amount of hot water and the time needed to reach the desired level, compared with the previous model. Adjusting the opening speed of the hot-water control valve at the second and third stage, it is possible to set up the most suitable conditions for the site auxiliary equipment.