Solar Power World posed a few questions relating to the solar hot water industry to Chris Wetherby, the leader of the Renewables Deptartment at Stiebel Eltron, manufacturer of solar hot water equipment.
Chris Wetherby is the leader of the Renewables Deptartment at Stiebel Eltron.
Solar Power World: How is the solar hot water industry doing?
Stiebel Eltron: Generally solar hot water sales have been flat, or trending downward slightly over the past few years, due in large part to more affordable, easier to install PV.
At the end of 2013, there were 201 companies in 43 countries manufacturing flat plate collectors and 85 vacuum tube collector manufacturers in 22 countries. Obviously, there was plenty of capacity to supply solar hot water equipment.
Part of the trend may be that national promotion of solar hot water (SHW) is nonexistent in the U.S. SHW is not a demonstrated technology at the National Renewable Energy Laboratory in Boulder, Colo. That is discouraging of itself, but more so considering that SHW is 4 times more efficient than PV on a KWH produced per square foot of collector surface.
Most people think “solar” is only PV. There seems to be a lack of understanding by the general public.
How is solar hot water technology changing?
SHW technology, like PV, has seen steady improvements year-over-year during the last 15 years. However, both the basic technologies have remained essentially unchanged over the past 60 years or so. Both technologies shine like the sun when appropriate engineering is applied to the project at-hand.
There are many types of solar water heating technology that exist and serve the myriad regional markets, e.g. thermo siphon, drain back, open loop, steam back, closed loop. Each technology has its place in various regions around the world as the more appropriate application of technology.
Integrated solar energy production monitoring will, in my opinion, validate SHW as a viable renewable energy technology and provide a platform for SRECs (Solar Renewable Energy Credits) in the SHW market.
What’s one mistake you often see made when it comes to solar hot water installations?
The biggest mistake is lack of follow up by the installer in the first few months after the installation is completed. It’s a critical time to ensure the correct functioning of the system and to see if the customer is satisfied.
What’s Stiebel Eltron’s latest product for solar applications and how does it improve upon previous versions?
The Sol 27 flat plate collector with installer friendly racking systems (both made in Hatfield, Mass.). Steam back over heat protection ensures the customer never has to worry about system overheating during power interruptions. SolarWave provides remote configuration and online computer monitoring with a record of solar energy produced.
What’s next for the solar hot water industry?
Integrated SHW/geothermal systems in main stream housing and affordable SHW/Radiant/Electric heating systems for low-energy homes. These concepts are already being implemented by creative system designers and installers! SPW