6 Politekhnichna Street
Building 5, floor 8, room 801
Five programmable logic controllers (PLCs) and a touch-screen panel computer monitor and control groups of engineering equipment at the Phnom Penh ice rink. The PLCs are installed in five control cabinets:
Chiller 1 and the main circulation pumps maintain the rink-floor temperature. Pumps P1.1 and P1.2 operate as a duty-and-standby pair, switching roles every 72 hours; the standby pump starts if the active pump stops. Pump P2 starts when the ice-resurfacer water-heater tank falls below its setpoint and stops when the temperature rises above the setpoint. Pump P3 for the dehumidifier’s air preheater runs with the dehumidifier.
The AHU includes supply fans, dampers, filters, a cooler, a heater and a rotary heat-recovery unit. Fan speed varies to keep room CO₂ below its setpoint; supply-air temperature is adjusted to control room temperature. The rotary heat-recovery unit runs while the AHU is on and uses cold exhaust air to pre-cool incoming outdoor air.
Chiller 2 supplies cooling liquid to the AHU cooler. A control valve regulates the heater to maintain supply-air temperature. Differential-pressure meters monitor filter loading and trigger an on-screen alarm when pressure drop indicates a dirty filter. The dehumidifier starts when room humidity exceeds its setpoint and stops when humidity falls below the setpoint minus a 5% hysteresis. Chiller 2 also supplies heating liquid for the AHU and supports temperature control of the snow-melting pit.
The panel computer or a web browser displays current values such as temperature, pressure and humidity; equipment states; active alarms; and historical parameter and alarm data. Operators can adjust setpoints, start or stop the ice, air and snow systems, and reset ice-system pump alarms. Chiller alarms must be reset at the chiller’s local control cabinet.
Parameter and alarm history is stored on the panel computer for one year; older records are deleted automatically as storage is reused.
