Future Active Solar Space Heating System

In future, sometime after having finished the sunroom, I intend to install an active solar thermal space heating system. This system will be composed of solar thermal water heating panels, specially designed and made radiant baseboard heaters filled with PCM thermal mass, distribution piping, and a direct PV/DC pump setup. This system will be installed to enable me to eliminate my current use during a number of weeks of the winter of my paraffin heaters and its petroleum-distilled paraffin liquid fuel.

I will make special solar thermal water heating panels to cover much of the south wall exterior surface. These panels will basically be coils of copper (or aluminum) piping with aluminum fins, both painted black, which will better absorb and conduct this heat to the antifreeze liquid in the piping. This piping with attached fins will be enclosed in thin insulated box panels. These box panels will probably be made of wood for its exterior with special interior rigid foam board insulation with interior-facing surface radiant foils. The top of the panel will be glass to allow solar radiation to penetrate and strike the piping. The box will be properly sealed to make it fairly air-tight.

The solar thermal panels will transfer their heat to a water-propylene glycol mixture that acts as the heat transfer medium. The propylene glycol is added to the water to drop the water's freezing point and thereby making it very difficult for it to freeze. This heated water is pumped to the heaters in the bedrooms and bathrooms through insulated copper piping. The water will be pumped using a small hot-water DC pump that will be powered directly from a small PV panel. There will be no thermal differencial on-off switch and sensors. When there is enough sun to power the slow-pumping DC pump with the small PV panel, there will be enough sun to heat the solar thermal panels to add energy to the PCM contained within the baseboard heaters. The piping system will have a one-way valve to stop any unwanted reverse flow of heat to the outside at night or during cloudy days.

I will design and make special baseboard radiant heaters filled with PCM thermal mass (unless a similar, affordable product is commercialized before then). These baseboard heaters will just off the floor attached to the walls. They will run the lengths of the walls and be from 10 to 20 cm wide and a few centimeters thick. These baseboard heaters will be metal enclosures filled with special PCM thermal mass in the center of which will run the copper piping with special heat-radiating fins. These fins will transfer the heat of the water in the copper piping to the PCM for storage. The PCM will absorb as much heat as given by the solar panels and then release this heat through conduction to the metal enclosure, which in turn radiates the heat to the room, when room air temperatures begin dropping. In summer, these PCM thermal mass baseboards can work in reverse to absorb heat from the hot interior air during the day and then have the heat pumped to the exterior during the cold night for night-time flushing - to make this work more efficiently, the water should not run to the solar thermal panels but rather be diverted to another set of panels or tubes specially designed for quickly releasing heat to the exterior air or ground or cold body of water.