SINGLE-EFFECT STEAM-FIRED ABSORPTION CHILLERS 16TJ 11-53 Fast digital PID control
The introduction of new digital PID control stabilises the chilled water temperature with high accuracy. It quickly responds to the load ﬂuctuation and supplies stable chilled water temperature. It is suitable for air-conditioning intelligent buildings which require sophisticated control.
Graph 5 - Steam valve opening control
Variable (5-30 minutes) Example: 15 minutes 30 minutes Steam consumption
Steam control valve opening ratio Cooling water entering temp. Chilled water entering temp.
Setting 7 °C
Chilled water leaving temp.
Graph 4 - Running cost curve
Expansion of safe operating zone
Energy consumption ratio (%)
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
Maximum input (%)
100 80 60 40 20 0 H--13 H--4
Cooling water entering temperature (°C)
H = 32 °C (variable from 20 °C to 33 °C)
Cooling load factor (%)
Notes: 1. Chilled-water leaving temperature 7 °C constant 2. Cooling water entering temperature:
Load factor (%)
100 50 30
32 27 25
The high-performance purge system maintains the required operating pressure, preserves chiller performance characteristics, minimises chiller maintenance to one purge operation per season (for yearround operation).
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.
Steam valve opening control
At the start-up, the opening angle of the steam control valve is controlled in three stages, reducing the amount of steam and the time needed to reach the desired level, compared with the previous model. Adjusting the opening speed of the steam control valve at the second and third stage, it is possible to set up the most suitable conditions for the site auxiliary equipment.
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.
Steam consumption (%) Steam control opening ratio (%)
Saving energy with the inverter (option)