Yup, that compressor and tubing and fins is describing a refrigeration cycle. In the summer you are using it like a traditional AC where it soaking heat in your mini split and sending it out to the heat exchanger outside built around your compressor to dump that heat in a hotter environment than inside your house (amazing I know!) due to the change in properties of the refrigerant when compressed (or expanded). This process is effectively reversed in the winter to take energy which exists in the cold outside air and pulls it in to your house by expanding it outside. Compressing or expanding the refrigerant effectively makes it colder or warmer (whatever is advantageous for the situation) to be able to extract or dump heat into it.

They probably mean mini splits which are usually attached to heat pumps which I think they implied by the savings in the winter