FEB 09

When we think about adding solar power to our homes, super-sexy photovoltaic panels get most of the attention. But photovoltaics are extremely expensive while solar water heaters can save power at a much lower cost.

I've been assuming that there simply isn't a lot of room for innovation in the solar-water-heater field. I mean, they're just black tubes with water running through them, right? But apparently I was wrong. An Irish company has just received independent certifications of its claim that their solar water heaters are as much as 131% more efficient than other solar heaters. The efficiency gains are enough to reduce the payback time for these systems by as much as 50%. That time, of course, will depend on how much sun your roof gets.

The company, Surface Power, says that the panels are more technologically advanced, but not much more expensive than other systems. Unfortunately I haven't been able to decipher what exactly makes these panels more efficient than others, but I'm still on the lookout.

The new panel was designed specifically for the renovation market. Surface Power wants to be a part of the new efficiency markets that the economic downturn, and resulting stimulus packages, will likely create. And since these panels can reduce hot water electricity use by 70% even in stormy Ireland, this could be a pretty good step toward decreasing the U.S.'s power use.

Surface Power has a lot of growing to do, though, before they can make a significant impact. They're still a small company, and most green consumers still spend most of their time thinking about photovoltaics. I think it's time we look at solutions that will work for us today...and this is certainly one.

Via RenewableEnergyWorld

Comments (15)

Subscribe to this comment's feed

Link
written by fredmac, February 09, 2009

Please, don't forget to give us the only interesting link.
http://www.surfacepower.ie/pdf/solar_systems.pdf

N'oubliez pas de nous donner le seul lien intéressant.

Cordialement

• 
• +0
• 
• 

UK solar power
written by Nick Maynard, February 09, 2009

Hank,

I'm not sure how this would stand up to real statistics, but my gut feel is that here in the UK most people identify solar hot water as the "main" solar power, rather than photovoltaics.

This may or may not be due to our climate, and ROI timings.

Nick

• 
• +1
• 
• 

Solar Water Heaters
written by Enrique, February 09, 2009

Hank or Anyone:
Do you know how much is a solar water heater for a typical home in the U.S?, and How much will the more efficient solar water heater cost?

• 
• +0
• 
• 

Good source for SHW / Photovoltaic infom
written by Luke, February 09, 2009

Enrique,

I've been subscribing to Home Power magazine for a while. Their print magazine and also their website has a lot of information on solar hot water (SHW), including approximate prices and performance specs. Also, they do case-studies of interesting houses and out-buildings. They also cover residential-scale wind and hydro power and talk a little bit about building-code compliance issues, tax breaks, and other relevant issues. I've learned a lot from reading the magazine over the last year or so.

http://www.homepower.com

• 
• +0
• 
• 

Brazil
written by Salles, February 09, 2009

Here in Brazil, a solar heater is very unexpensive (we get a return of the investment very quickly)... A solar heater for a house with 5 people costs about R$ 2000,00 (less than US$1000) and it is very good.
Actually, we have a very good weather and we can use even homemade solar heaters (i have already made one here... but nowadays we use a comercial solar heater).

• 
• +0
• 
• 

re above
written by Mark Bartosik, February 09, 2009

I see precious little technical details about surface power's efficiency break though, and what they are comparing against. I've often heard existing solar thermal described as 80% efficient. So how can we have a gain of 131% over 80%?

Hank, maybe Surface Power will response to an inquiry from you?


I second the link to http://www.homepower.com
I'm a subscriber and it is a great magazine.

Which is more cost effective PV or solar thermal for residential depends on several factors. For example, in some cases rebates can cover over 75% of PV costs, but only 20% of solar thermal. Solar thermal can be more difficult to install e.g. in drain back systems all pipes must run down from collectors to drain back tank which is hard but not impossible with ground mounted systems. Closed loop systems have other issues like "stagnation". Whereas with PV electrons run up and down hill and wires are easier to run than pipes, and with grid tie PV the grid will always consume excess production, whereas your utility won't buy your excess hot water.

• 
• +0
• 
• 

Evacuated Tubes
written by Carl, February 09, 2009

The efficiency quote has to do with the type of collector under certain weather conditions. The most common collector is a glass covered box with tubes inside. An alternative is essentially a glass dewar flask-- a glass outer tube, a dark collector tube inside with a vacuum insulation in between. These collectors work well even in cold weather and diffuse light on cloudy days, though are more expensive per m2. For certain climates, the evacuated tubes will have lower $/BTU, and/or might be useful for more days of the year. In most climates, these are less efficient though.

Note, this quote is marketing from an installer, not a new technology. Detailed performance is available at http://www.solar-rating.org/ A great article on the different systems is at http://www.homepower.com/view/...g66_Marken

My apartment has solar hot water installed in the post OPEC-embargo of the 70's (or early 80's) when there was a tax-credit. Now, I see few solar hot water installed here in N. California. Instead people are installing PV, probably because of the tax/rebate incentives.

• 
• +0
• 
• 

Efficiency
written by Paul, February 09, 2009

Evacuated tubes are efficient but expensive. There is an American made collector that is one of the most efficient units on the market with simple technology and no electricity needed.
http://www.solreliant.com/

• 
• +0
• 
• 

...
written by MD, February 09, 2009

Here you go, read up, have fun, don't scald yourself.

http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm

I have to laugh, these things are pretty much pool water heaters, and they work.

A draft dodging hippie friend of ours on Hornby Island BC Canada has a heater made from U75 black utility pipe coils on his roof, the water in the coils gets so hot that you can get burned, so be carefull!

IIRC, Hawaii know requires these heaters on new home construction.

• 
• +0
• 
• 

Solar Hot Water Heaters
written by Rex, February 10, 2009

With a proper feedback loop and an extra 50 gallon primer tank you make just a small inefficient collector work well. Although the evacuated tubes are the most efficient and pleasant to look at to boot.

We install these with solar PV systems regularly in Texas although it is still a very small % of homes that have them.

Texas Solar Power Company -- Installs across the nation since 1995.
http://www.txspc.com

• 
• +0
• 
• 

Ugh! Another relative percentage compari
written by ctyanlee, February 19, 2009

I would like to propose that the 131% earn the claimant some jail time or public service.

It's like an "up to 52% closer shave". Put an absolute number on it or shut up about numerical claims.

Sheesh! {sorry for the rant}

• 
• +0
• 
• 

answer to question
written by Sunbelt Solar, June 04, 2009

Hank or Anyone:
Do you know how much is a solar water heater for a typical home in the U.S?, and How much will the more efficient solar water heater cost?

solar water heaters in the U.S. depend alot on location and the type of system used. They can range from $4000 in Southern areas where freezing is not a concern to $8000 in northern climates which require special systems. we have more information about solar water heaters in the U.S. on our website http://www.sunbelt-solar.com

• 
• -1
• 
• 

solar vs tankless
written by freenergy, July 16, 2009

On top of the energy savings, most customers are seeing solar hot water as a luxury. Our last customer was ecstatic to find she could now heat up her entire 70 gallon bathtub for the first time. her backup heating element never even came on.

• 
• +0
• 
• 

...
written by Linda, April 07, 2011

If you want to get hot water instantly and save the money as well, go for tankless water heater.

• 
• +0
• 
• 

NZ Solar Energy
written by ChrisNZ, June 13, 2011

HI from way down here. Were having to replace a built-in fireplace with a wet back. We are also looking at the Solar Water heater systems and Evac tubes sound like the way to go. WE have suitable pitch to the roof that faces the sun all day and really dont want a tank if we can help it? I'm now seeking info in NZ for the best options and learning along the way! Really think that anything that can reduce the amount of power consumption and no/low emission is the way to go.
Cheers from here.

• 
• +0
• 
• 

Name

Email

Website

Title

Comment

smaller | bigger

Subscribe via email (registered users only)

Write the displayed characters

Add Comment