Direct vs. Indirect

Explaining the Competition:

Direct solar water heating systems pass potable water through the thermal collector that eventually flows directly to the desired application (the faucet, the showerhead, etc.).  Indirect solar water heating systems circulate a fluid – typically a mixture of water and glycol – in a circuit between the rooftop thermal collector and a heat exchanger that actually warms the potable water.

Traditionally, indirect systems are more successful nationwide than direct systems because of their resistance to cold.  Indirect systems circulate collected heat to a storage tank in a basement or utility area.  In the winter, this is a much lower threat of heat loss than an outdoor storage option.  Also, all of the water flowing outside in an indirect system is laced with antifreeze to prevent expensive damage to the system.

However, without that winter weather advantage, it would be irrational to choose an indirect system over a direct system.  Indirect systems require an additional pump to circulate the fluid through the closed-loop system.  These pumps will need to be maintained regularly and replaced at least once during the lifetime of the collectors.  The pump will also require additional electricity to power its operation.  The water-glycol mix that typically fills the circulating closed-loop systems needs to be replaced every few years, which adds a regular expense to operating an indirect system and increases the pollution of an otherwise green product.

The GLE Solar Advantage:

GLE Solar products are the first direct solar water heating systems designed for any U.S. climate in any season.  The natural benefit of an evacuated tube is its resistance to heat loss.  Solar radiation can easily cross the vacuum layer, and only an insignificant amount of heat can return.  Our evacuated tube units contain a much higher volume of water than any other existing solar product, which gives the contents a high thermal mass.  The high thermal mass slows down heat loss through the collector components in the bottom frame of the unit that are not protected by a vacuum layer.

Customers no longer have to choose between a winter-friendly solar water heater and a low-maintenance, easy installation.  The ideal green system would maximize heat collection, minimize losses, and avoid toxic byproducts like antifreeze.  GLE Solar provides that ideal green water heater.