Overview
This purpose of this project is to collect and store as much heat as possible. It's really more of a framework than a strict set of plans; people with particular constraints, assets, or requirements should adapt this project to their situation accordingly. The parts are fairly easy to come by, with a few notable exceptions. Also, every part of this system is scaleable. Need more hot water? Add more storage. Need hotter water? Add more collectors.
At almost every stage of this project, insulation must be one of the foremost concerns. This apparatus has the ability to collect great amounts of heat in a steady, consistent way -- but this will only work well if every possible vector for heat loss is addressed.
The project consists of a few general pieces:
- collection
- storage
- tubing
Collection
The basic collection piece generally consists of an involute trough and a vacuum collection tube. The trough's particular shape, generated as a specific mathematical compliment to the collection tube, reflects most of the light that falls into it onto the tube. In this way, it can be thought of as a stationary tracking system. If it's built and deployed properly, it should be able to be used year-round with no daily or seasonal adjustments. The trough is highly reflective, generally lined with something like mylar. A copper manifold (made from off-the-shelf plumbing parts) is used to actively move water through the vacuum collection tube and facilitate the heat transfer.
Storage
The storage system is essentially the battery (albeit a thermal battery, instead of the chemical batteries we're all familiar with). It's really just a heavily insulated tank. Water (or whatever medium you're using) flows out of the storage tank, though the tubing to the collector(s), and then back again. The storage tank is also the point at which the other systems draw upon the collected heat.
- Pre-heating hot water can easily be accomplished by routing the incoming cold-water line through the reservoir first, and then on to the hot water system.
- Radiant floor heating could draw water from the primary storage tank into a secondary mixing tank (to decrease the water temperature down to the ideal for radiant floor heating, around 105F), which then supplies the lines under the floor.
- If the collection temperatures are high enough, DC electricity can be generated using a Peltier junction. Extremely hot water is drawn from the top of the tank to be applied to one side of the Peltier, while a dedicated ground-water loop feeds the cold side.
Tubing
The tubing will carry the water from the storage tank, to the collectors, and back again. It represents one of the greatest risks of heat loss, and must be extremely well insulated. Also, depending on issues such as dealing with freezing, it may need to be installed with a consistent slope, allowing the water to drain back into a protected area without pooling in the lines.