What can I do with excess energy in the summer?avwFm87mDz
Three choices- Steam, Drain or Dump. For most places in the US, there will be more solar gain in the summer than in the winter. This occurs during a time when your load is lowest, so that means EXCESS HEAT. You must deal with this if you are to design and/build a solar thermal system that stands the test of time.
Steamback system- this system design will allow for the steaming of your heat transfer fluid during times when the pump is off. Normally this is somethin you try and avoid, but if designed properly you can use the steam pressure to your advantage by forcing the Glycol out of the collectors and allowing the system to stagnate. Many of the millions of systems installed in Europe use this design strategy.
Drainback system- this system design will allow for the HTF to drain out of the collectors during times when the pump is off. If the collector is empty of fluid, then there is no danger of overheating. Long considered an american invention, the drainback system is a fail safe and fail proof AS LONG AS IT IS INSTALLED BY A TRAINED PROFESSIONAL. Drainback are typically NOT for your average DIY’er where Steamback IS.
Dump- a heat dump is a place off of your solar loop where you can dump vast amounts of excess energy without negatively impacting any other aspect. Can someone say SWIMMING POOL? these are the best heat dumps because they not only can store huge amounts of BTU”s but also because a warm pool is a happy wife.
An effective heat dump can also be a radiator with fan that blows air across the coil, a buried line, a large watering tank, a hot tub, finned copper lengths etc- these would all be piped in PARALLEL with the storage tank for best results.
A unique option for heat dumping is the Butler SPOC, by Sunmaxx, click here to view this product. This method of heat dumping is passive and 100% fail safe (if it installed properly)
Mounting strayegy can also be used as effective over-temp protection. By tilting the collectors at a very steep angle, we can reduce our summertime production by nearly 40%