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Heat pump controller RS8GF202 © Danfoss 2015-08
AK-HP 780
Heat pump plant example
We have decided to describe the setup by means of an example
comprising a compressor group and a "pump".
The example is the same as the one given in the "Design" section,
i.e. the controller is an AK-HP 780 + extension modules.
Compressor Group
• Refrigerant CO2 (R744)
• 4 only compressors with "Best fit". Speed control on one.
• Safety monitoring of each compressor
• Common high-pressure monitoring
• Sctrl setting 60°C, Night setback on 5 K
• Oil management of each compressor
• Pulse reset of stopped compressor (oil shortage)
Pump:
• Pump with speed control
• S7 setting 40°C
Receiver:
• Monitoring of liquid level of refrigerant
• Control of pressure in oil receiver
Fan in plant room:
• Thermostat control of fan in engine room
Safety functions:
• Monitoring of P0, Pc, Sd and superheat in suction line
• P0 max = 10°C, P0 min = -2°C
• Pd max = 50 °C
• Sd max = 120°C
• SH min = 5 °C, SH max = 35 °C
• Monitoring of low and high level in oil receiver
Other:
• Alarm output used
• External main switch used
For the example shown we use the following modules:
• AK-HP 780 controller
• AK-XM 102B digital input module
• AK-XM 205B input and output module
• AK-OB 110 analog extension module
There is also an internal main switch as a setting. Both must be “ON”
before any adjustment is made.
The modules used are selected in the design phase.