Yes, the terms can refer to different things. There are two types of heat pumps (and A/C units in general). There are "air source" and "ground source." Ground source is often known as Geothermal and is much more efficient and sustainable.
Air Exchange could refer to air source A/C (or heat pump) but that is not very likely. Air Exchange is much more likely to refer to any system which pulls in outdoor air and exhausts indoor air to keep the air inside fresher. You hope that if a house has an "air exchange system" in place, it utilizes an HRV (or Heat Recovery Ventilator) because they are much more efficient. So much like a humidifier, an "Air Exchange" system typically has nothing to do with heating or cooling the house, but rather is an optional add-on to keep the air fresher.
A note on sustainability
Due to the comments below, I realized that I need to add a note here first. I have to admit that I don't really know much about grids and alternate fuel sources outside of Continental USA. When I talk about burning gas, I strictly am talking about propane and natural gas. I now understand that these resources are not available everywhere and other fuels such as oil are dirtier to burn. I also understand that some grids are much "Greener" than other grids. The following paragraph is just my experience and should just give some things to think about when analyzing what will be best for your location.
Some people have installed heat pumps and found adverse effects on their energy consumption and sustainability. It all depends on how warm it is, the cost of electricity (vs gas), and where the electricity is coming from. If you install enough solar to compensate for the extra electricity usage, then a heat pump is hands down the best thing to have (especially a ground source). Notice that air source heat pumps don't do well in cold climates (where you need it the most). If you are using electricity from the grid then it is helpful to know that most grids around here are much dirtier than using a high efficient furnace (look for 95% efficient or 90% at the lowest). So, (in my region) if you are considering the environment, you should weigh these factors to determine if it's better to use a high efficient furnace or a heat pump.