Solar Thermal | Sun Volt Solar Blog

Solar Equipment Service Calls

12 Jul 08 | Solar Electric, Solar Hot Water, solar thermal

I have been receiving many calls from home owners with old solar equipment installed on their houses. Mainly, they are interested in seeing if the equipment is working or is worth repairing. What I am finding is that in many cases, it is worth the effort to repair these systems.

Last week I came across a drain back solar domestic hot water system that was installed in 1980, After 28 years, It was still working. The home owner had a pump replaced by the local plumber. Unfortunately, I think the plumber did not fully understand the concept of the drain back tank.

The problem with that system was the pump was installed higher than the bottom of the drainback tank, so it was cavitating every so often. I filled the drain back tank to the top and that reduced the cavitation but did not eliminate it. Even so, it seems to be working well and the homeowner was happy that they were back in hot water, so to speak. A well maintained solar domestic hot water system, particularly a drain back system, can last almost indefinitely.

Another antifreeze type system was left to stagnate over several years. I seems that some of the antifreeze has boiled off. This system needs to have its HTF (Heat Transfer Fluid) flushed out and replaced. While I was there, I pressure tested the solar loop to see if there were any leaks. After several minutes, the pressure began to rise as the panels heated up in the sun. After a good flushing and a few gallons of Noburst-100, the system should be good as new.

Was is really great to see, is that many of these orphaned 1980’s era solar systems are actually in good shape and with a little work can be put back in working order. I am also enjoying the challenges of trouble shooting of these legacy systems. No two systems are alike and they all seem to have different problems.

If you have an old solar system on your house, it may be worth it to see if it can be put back in service. If you have a working solar system, it may be good to have somebody look at it and see if there are any problems. Contact us for more information.

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Tags: solar service

12 Jul 08 | Solar Electric, Solar Hot Water, solar thermal | Comments (0)

Something to think about when calculating ROI

07 May 08 | Sales, solar thermal

In my sales manual, I have a whole section devoted to Return on Investment (ROI) for SDHW systems. Basically, it shows the money saved by reducing energy use vs. the cost of the solar system minus the incentives. I have several charts that show the different conventional fuel type and how they compare with SDHW, when the payback will be, what a payment would be on a financed system, etc. Most clients eat this up as it is the nuts and bolts of any sales presentation.

One problem I have is predicting the future price of energy. For the purpose of the sales presentation, I use a standard 2.3 percent inflation figure. As everyone knows, energy has been rising at a much higher rate than that.

I read a very interesting article on The Oil Drum about the possible future prices of a barrel of oil. It does not look good. Grant it, these guys are the peak oil gloom and doom predictors, however, it must be said that everything they have predicted so far has come to pass more or less. Based on market pressures, their analyst is predicting $200.00 per barrel oil by 2010 and a steeper rise after that. This is supported by Goldman Sachs group which states:

The possibility of $150-$200 per barrel seems increasingly likely over the next six-24 months, though predicting the ultimate peak in oil prices as well as the remaining duration of the upcycle remains a major uncertainty,” the Goldman analysts wrote in the report dated May 5.

This is a chart from Oil Drum showing predicted prices for the next decade:

As goes the price of oil, so goes the price of electricity, propane, heating oil, natural gas, food and all the other energy sources. Of course, this is a difficult concept to convey to most people because they don’t understand how much our society depends on oil to function.

The current high gas prices at the pump are only a small inkling of what is in store for the next winter’s heating season. I have a feeling that a lot of people are going to have to make some tough choices next winter.

As always, it is difficult to tell what the future has in store for us. Without being too alarmist, I try to convey to the potential client that now is the best time to install one of these systems because as the price of energy goes up, so will the price of materials. A small sacrifice now may reap large rewards later on.

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07 May 08 | Sales, solar thermal | Comments (0)

The other Solar Thermal; Solar Hot Air Collectors

22 Apr 08 | solar thermal

We have written a good deal about solar thermal on this blog. One thing that has not been covered are Solar Thermal air collectors. These units look similar to hot water collectors, only they use air as the Heat Transfer Fluid (HTF).

Solar hot air collectors have several advantages; They are easier to install and many do-it-yourselfers can install one or two hot air panels in a weekend. They can be mounted on south facing walls or roofs. Shading by deciduous trees is not an issue, since summer time heat production, in most cases, is not desired. They do not contain liquid, so freeze protection is not necessary. They also can most often be power by a small PV panel, which means they require no outside energy input.

The main disadvantage is they have no heat storage capacity, nor can their heat output be transported easily to another part of the building. When the sun is shining, you get the full effect of the sun’s energy (about 1 KW per M²), minus the incident angle losses. For the average solar hot air collector in a category C environment, that is about 10-14 KBTU/day per Ft². They are also slightly less efficient than liquid flat plate collectors because water is a better HTF than air.

There are two companies that make SRCC certified solar air collectors, Your Solar Home and Environmental Solar Systems. They consist of a flat plate collector with solar selective coating in and aluminum frame. Both units have DC powered fans, one comes with a 14 watt PV panel, the other comes with a wall transformer for 120 VAC. They look comparable in size/output and price. One is made in Canada, the other in Massachusetts.

A real DIY person could potentially make their own solar thermal panel if they had the proper motivation.

Update: Stephen let me know that my research was not a through as it should have been:

You missed the solar hot air units from Newfoundland Canada. I am a reseller of the product.They have over 1000 of them out in the real world. They work well in Newfoundland where they only get 1500 hours of sunlight.

Their website:

Cansolair Solar Panels

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