This is a common question from people who want to retrofit a solar thermal space heating system. The simple answer is "Yes, you can integrate the two systems." The reality of the process is a little more complicated.

Before you begin, it is important to note that this is not a recommended integration in new builds using renewable energy. Systems with blowers should only ever be used in heat-recovery ventilation or fresh air systems in commercial buildings. They use an awful lot of electricity (too much to be powered by PV panels) and you'll be better off with radiant floors or another solar-compatible option.

Assuming you already have a forced-air system in place, the ductwork and blowers can be used to push the heat generated by a solar thermal space heating installation around the building. To do this, you'll need to install a liquid-to-air heat exchanger (heating coil) near the furnace, preferably in the hot air duct above the furnace itself and below any existing heating coil. This is important because the AC-powered system pumps cold air around in summer and, if the solar coil is above the AC system's coil, the cold air can freeze the solar coil.

If you can't install the solar setup's exchanger coil in the hot air duct, you can put it in the cold air one, but you'll have to move the furnace's air filter so that it works before the air hits the solar coil.

The system works as you would expect: the heat generated by the solar thermal installation is transferred into the air in the ducting via the coil and passes around the building. If your solar thermal setup has no heat storage tank, the collectors dump their collected heat direct into the ducting; if you have a tank, the heat goes there first (for storage), then to the ducting on demand.

You will also need to install some controls to ensure the two systems work together.