Modern HVAC systems are already power-electronics machines, not simple on/off electrical loads. That is why they fit naturally into the Energy Internet idea.
A modern HVAC system (heat pump or air conditioner) does not run its compressor directly from the AC grid. Instead, the incoming AC power is first rectified to DC. That DC is then used to drive an inverter (a variable-frequency drive, or VFD), which synthesises a precisely controlled AC waveform for the compressor motor.
Grid AC → DC link → power-electronic inverter → motor
A modern HVAC compressor motor is best understood as a digitally controlled electric machine, not a simple mains-powered motor.
In most modern heat pumps and air conditioners, the compressor is driven by either a permanent-magnet synchronous motor (PMSM) or a brushless DC motor (BLDC). In practice, these are very similar machines; both are powered and controlled by electronics rather than the grid.
The motor itself has a rotor with permanent magnets and a stator with windings. There are no brushes, no commutator, and no mechanical switching. Torque is produced by creating a rotating magnetic field in the stator that pulls the rotor magnets around.
https://classx.org/scroll-compressor-exposed-understanding-its-mechanical-magic
Crucially, the stator windings are not connected directly to AC mains. They are driven by a variable-frequency inverter that creates exactly the voltage, frequency, and phase angle the motor needs at any moment.
Because of this:
- Motor speed is fully controllable. Speed is proportional to the electrical frequency generated by the inverter, not the grid frequency.
- Torque is fully controllable. Torque depends on current, which the inverter regulates directly.
- Power draw is continuously variable. The motor can run at 20%, 40%, or 100% output without switching on and off.
The compressor itself is typically a scroll compressor or rotary compressor, mechanically coupled directly to the motor shaft. There is no clutch. Changing motor speed directly changes refrigerant flow and therefore heating or cooling output.
This architecture gives several important properties:
- Soft start: No inrush current. The motor accelerates smoothly from zero speed.
- High efficiency: Permanent magnets eliminate rotor losses found in induction motors.
- Wide operating range: The compressor can run slowly for long periods instead of cycling at full power.
- Fast response: Power can be increased or reduced in milliseconds.
In Energy Internet terms, this is decisive. The compressor motor is already a packet-friendly load. Its power electronics allow it to accept limits, ramps, and short reductions in power without stopping, tripping, or affecting comfort.
That is why modern HVAC compressors are not a problem for a constrained or router-managed grid. They are one of the best assets for reducing peaks, stabilising voltage, and smoothing demand—because they are already digitally controlled machines, waiting to be coordinated.
This architecture gives the controller direct authority over motor speed, torque, and power draw.
Because the compressor speed is controlled electronically, the system no longer has to cycle on at full power and then off again. Instead, it can modulate continuously. When only a small amount of heating or cooling is needed, the compressor slows down and draws much less power. When more output is required, it speeds up smoothly.
This is why modern “inverter heat pumps” are quieter, more efficient, and gentler on the grid than legacy units.
From a power-system perspective, the crucial point is that the compressor does not care about the grid waveform. It only cares about the DC it receives from its internal power electronics. That means its electrical demand is already abstracted from the grid.
This abstraction allows several forms of control that are directly relevant to Energy Internet operation:
First, power limiting. The controller can cap the compressor’s electrical input to a specific wattage without shutting the system off. Instead of tripping or cycling, the heat pump simply delivers slightly less heating or cooling for a short period.
Second, ramp-rate control. The compressor can be instructed to change speed slowly, avoiding sudden current spikes that stress the network.
Third, time shifting. Because buildings have thermal mass, heating or cooling can be done a little earlier or later with almost no impact on comfort. The power electronics allow this to be done precisely and automatically.
Fourth, graceful degradation. If the grid or router signals congestion, the HVAC system does not disconnect. It smoothly reduces output and continues operating at a lower power level.
In Energy Internet terms, this means a modern HVAC system behaves like a polite, schedulable load, not a blunt one. It can accept “packets” of energy spread over time rather than demanding a fixed instantaneous draw.
This is why HVAC is so valuable in a router-based system. It represents a large fraction of household peak demand, but it is also one of the easiest loads to modulate invisibly to occupants.
So when Jonas talks about energy being managed in bursts and controlled at the edge, HVAC is not a future example — it is a present-day proof. The power electronics are already there. What is missing today is simply the system-level permission and coordination to use that capability in service of the grid and consumers.