Technology of The Simple Drianback

Heating your hot water with the sun simply makes sense. We have developed the new Simple Drainback System to make heating your hot water even easier. Our designs save time and money on installation, training and maintenance. Simple plumbing methods combined with high quality equipment create the next generation of solar hot water systems.

Simplicity.
The Simple Drainback system was designed to bring the simplicity of drainback systems together with some of the better characteristics of pressurized systems to create the easiest installation on the market. We have integrated the standard small drainback tank with the storage tank, eliminating the extra tank, plumbing and installation time associated with these components. The solar fluid is water which has better thermal characteristics than glycol, and is, obviously, less expensive than propylene glycol. The storage tank is filled with the solar fluid (water) and serves effectively as a heat battery to store the energy. The solar fluid circulates directly from the collectors to the tank and back using only one pump. This allows for very efficient and fast recharging of the storage tank.

Freeze Protection.
As with all drainback systems the freeze protection is attained through gravity. When the solar collectors are hot enough to heat the tank, the differential controller turns the pump on and water flows from the tank and back, heating the tank. When the collector temperature drops to the point where the tank will no longer benefit from the collector temperature, the differential controller turns the pump off, and the solar fluid drains completely out of the collectors and returns to the storage tank. The SHEM32 controller is set to prevent the pump from activating when the temperature in the collector drops below 50°F. This provides an additional measure of protection against freezing. Our controller is also passcode protected to prevent accidental adjustments of the temperature settings.

Domestic Hot Water.
The Simple Drainback system heats domestic water much the same way as an on demand hot water heater. The domestic cold water enters the tank and passes through the extremely efficient Hot Spring heat exchanger and comes out hot.

Ease of Installation & Training.
To add even more value to our Simple Drainback system it comes pre-assembled and the pump and differential controller are pre-wired. Simple training for plumbers and solar dealers to deploy these systems was a driving force in our design process. The system requires very little time to install. The tank is set in place, the solar inlet and outlet and domestic water inlet and outlet lines are plumbed, the solar sensor is wired to the controller, the tank is filled, and the controller is plugged in. By simplifying the installation and decreasing labor costs we have created a product that is another step toward making solar hot water a standard building system.

Maintenance.
Unlike pressurized glycol systems, our system runs on water. It is closed off from the air so there won’t be a need to refill. The solar water impurities that would cause corrosion in the solar loop will be “cooked” and settled out when the system first runs. The domestic water flows through a copper heat exchanger that should age no different than the copper pipes in a house. Our tanks are warranted for ten years and their expected life is over 25 years. Our solid state SHEM controller should operate flawlessly for the lifetime of the system. Wilo pumps are designed to self lubricate and handle temperatures above which our systems will run. The only maintenance required on our systems is a routine check to make sure the tank is hot on a sunny day. If the system is installed correctly it should supply free energy from the sun for 15 to 20 years or more. As with all equipment with moving parts, the pump is the most likely component to require attention. If that is the case, repairing or replacing the pump is a simple and relatively inexpensive fix and should extend the life of the system indefinitely.