Why don't heat pumps use multiple air sources

Sorry, that's a terrible title, but here is the question as best I can put it:


I live in an open loft area with a centralized heat pump. Often, I will find that though I have my thermostat on COOL, it is hotter inside than out. Often, when I have my thermostat on HEAT, it is colder inside than out.

It stands to reason that if I want to COOL the inside, the heat pump would have to do less work if it could choose the coolest source of incoming air (be it from outside or inside).

By that same logic, HEAT would simply pick the warmest source of air as it's starting point and apply heat.

Currently, all of the air is coming from inside and if it is hotter than outside, I have to cool all the air inside just to get relief. Sure, I could open a window, but I don't have any windows and no circulation for air.

I simply want a device that could act autonomously from the Heat Pump that sits directly in the air intake portion of the system.

When the heat pump starts in COOL mode, the first device (intake) would compare the temperature outside to the temperature inside and simple apply a mechanical switch to allow the coolest source to enter the heat pump.

When the heat pump starts in HEAT mode, the first device (intake) would compare temps and pick the hottest source.

Does this kind of thing exist? If not, let's build one and win a Nobel prize for the amount of energy we could save.

Any information would be greatly appreciated.