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Control system 2

PID continous control system for a heat pump.

This is an idea how to make a PID contoiuns control loop control system for a heat pump.
(Not yet tested.)

Figur 1 - A PID continious control loop control system for a heat pump. 

Fig 2 - A control loop shematic drawing of the control system.

The control system works like this:

Lets say the room temperature is 20 degrees Celsius. The set point for the room controller is then set to 24 degrees

The room temperature PID regulator (the left one) is sensing a difference between setpoint and feedback signal of four
degrees. From these values it calculates new values for the level two control loops, in this cascade control system.

The compressor control loop regulator starts to bring the suction pressure of the compressor slightly down. This is also
working on the condensator pressure in such a way that the control lop (the expansion valve) of the evaporator, so it will
open and let more refrig media pass trough. This will in turn bring more energy to the condenser.

As the control loop for the condensator cooling fan also receives an increased set point from "the outer control loop",
the fan of the condenser speeds up, transporting more heat energy into the room. (A slightly hotter condenser due to
increased pressure and also more heat energy transported away due to increased airflow.)