Is a Pump Necessary for Glycol-Free Drainback Systems?

Glycol-Free Drainback Basics

Glycol-free drainback systems are a type of solar hot water system that uses water as the antifreeze instead of glycol. These systems operate on the principle of draining water from the collector tubes when the system is not in use, which helps to prevent freezing and corrosion. By utilizing gravity, glycol-free drainback systems can be designed without a pump, reducing the complexity and cost of the system.

System Design Considerations

When designing a glycol-free drainback system without a pump, it’s essential to consider the system’s elevation and piping arrangement. A minimum system elevation of 10-15 feet is recommended to ensure that water drains from the collector tubes by gravity. Additionally, the piping should be sloped at a minimum of 1/4 inch per foot to facilitate drainage. A well-designed system can ensure that water drains from the collector tubes without the need for a pump.

Drainback System Components

A glycol-free drainback system consists of several key components, including a storage tank, a drainback tank, and collector tubes. The storage tank is where the hot water is stored, while the drainback tank is used to collect the drained water from the collector tubes. The collector tubes are typically made of a durable material such as copper or PEX, and are designed to operate at high temperatures. By selecting the right components and designing the system correctly, a glycol-free drainback system without a pump can provide reliable and efficient solar hot water heating.