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When the Sun Shone Upon Alexandria

Posted on | September 2, 2013 | No Comments

By Chuck Hagee

Photo 2--Former Sheet Metal Pension Fund Building

The building at 601 N. Fairfax Street, which sold for $21 million, formerly was once the world’s largest solar-operated commercial building and the home of the Sheet Metal Workers National Pension Fund, opened in 1986. Photo by Google Maps.

Alexandria was once the home of the largest solar powered commercial building in the world. Today the shell of that structure is being redeveloped into what will be some of the most luxurious condominiums in Old Town.Located at 601 N. Fairfax Street, the large battleship-like edifice opened in 1986 as the home of the Sheet Metal Workers National Pension Fund. Known as the Edward F. Carlough Plaza, in honor of the former president of that organization and founder of the pension fund, it received the Energy Conservation Competition Award in 1993. It was home to the pension fund as well as a conglomerate of other businesses.

At a time when the nation was facing a severe energy crisis, this 323,000 square foot structure was a beacon of light illuminating the future. Using an air-type collector system, it had a total heating and cooling budget of only $210,000 per year, less than $1.54 per square foot.

 

Once the largest commercial solar powered building in the world, the former sheet metal workers’ pension fund headquarters is now being converted to luxury residential condominiums that will range in price from $1.4 million to $4 million.  Photo by Chuck Hagee.

Once the largest commercial solar powered building in the world, the former sheet metal workers’ pension fund headquarters is now being converted to luxury residential condominiums that will range in price from $1.4 million to $4 million. Photo by Chuck Hagee.

That budget covered heating, air conditioning, hot and cold water, as well as the power used by the approximately 400 people working there daily. However, the owners did get a special rate because the building was solar.

Not only was the air to water system very efficient it was also very low maintenance, according to the building’s chief engineer at the time, Dennis Miller. The secret to the system’s success was the tubular design of the collectors on the roof. “No matter what the position of the sun the tubes were always working,” he explained.

Flat plate collectors do their best at collecting solar energy while the sun is shining directly on them, but the tubular design was able to collect useful energy from dawn to dusk. This was particularly significant on bad weather days and during the winter months when flat-plate design panels would drop productivity.

Each tube acted much like a thermos bottle. Air was drawn into the vacuum tube and subsequently forced out by a fan. The center of each tube was metal encased in a black shield to absorb the heat.

The outer casing was clear glass. Air from the solar roof-top panels was drawn across coils which heated the water which then circulated through the entire heating system.

On a hot summer day the temperature inside the tubes could reach 290 to 295 degrees. Yet, because of the thermos bottle concept, the tubes could be inspected by hand. It also encompassed a built-in fail safe system. If the temperature inside the tubes reached 385 degrees the system automatically shut down.

The original building contained a total of 5,810 solar tubes totaling 23,904 cubic feet. They were so well constructed that only about three tubes per year needed replacing. The primary source of damage to the tubes, according to Miller, was “the seagulls and the kids.” The blows from the seagulls were due to their droppings from above and kids did their share by throwing rocks from below.

But, the sun was not the only generation source. The other was water. There were 47,340 gallons of water stored in six 7,890 gallon tanks below the second garage level. The time for the water to make one complete cycle through the tanks varied from one hour and 30 minutes for cold water to two hours and 30 minutes for hot water.

Air from the solar panels was drawn across the water coils causing the water to heat. The purpose of the hot water was to cause evaporation in a lithium bromide solution which acted as a refrigerant.

As this solution cooled it flowed across a bank of chilled water tubes. This resulted in a three to five degree drop in the water temperature. The chilled water was then introduced directly into the absorption chiller. All this resulted in lower demand for electrical current.

During summer months the system was able to harvest 741,000 BTU’s (British Thermal Units) per hour for an 80 percent efficiency rating. During winter months solar power supplied approximately 45 percent of the heating load by supplying hot water to the return side of the electric hot water boiler.

Solar power also supplied 75 to 80 percent of the individual demand for hot water throughout the building. The system maintained a constant 135 degree temperature for individual use of hot water.

Known as a Thermal Storage System, it combined solar power with regular electric power. Dominion Virginia Power noted that the bills for the building were averaging 4.95 cents per kilowatt hour compared to the normal fuel/electrical rate of 6.11 cents per kilowatt hour.

This meant that the solar building was saving an average of $2,800 per month on its electric bill. A non-solar building of equal size would be paying an electric cost at that time of $18,800 per month compared to the solar building bill of $16,000 per month, based on a rate for large industrial customers.

The cost to construct the building in 1986 was approximately $14 million. Of that total approximately $1 million went for the solar heating/cooling system.

Unfortunately all of that is now history with the reconstruction of the building. When it opens sometime in the next year the heating and cooling system will be of the conventional type, according to the construction plans.

Artistic rendering of The Oronoco, an adaptive re-use of the former office building near the banks of the Potomac River that will be turned into luxury condos by EYA. The tiered design of the existing building will be used to incorporate private outdoor spaces for each residence. Shalom Baranes is the architect. Photo courtesy of EYA.

Artistic rendering of The Oronoco, an adaptive re-use of the former office building near the banks of the Potomac River that will be turned into luxury condos by EYA. The tiered design of the existing building will be used to incorporate private outdoor spaces for each residence. Shalom Baranes is the architect. Photo courtesy of EYA.

It will also no longer be a commercial structure but rather house approximately 60 residential condominiums ranging in price from $1.4 million to $4 million. And, tenants will be paying the regular utility bills.

 

The rooftop solar panels are gone, as are the large water storage tanks below the surface and the elaborate circulation system. History marches on. But, not necessarily forward. Alexandria has lost its claim to fame in the solar heating and cooling universe.

Once the largest commercial solar powered building in the world, the former sheet metal workers’ pension fund headquarters is now being converted to luxury residential condominiums that will range in price from $1.4 million to $4 million.

The rooftop solar panels are gone, as are the large water storage tanks below the surface and the elaborate circulation system. History marches on. But, not necessarily forward. Alexandria has lost its claim to fame in the solar heating and cooling universe.

 

 

 

 

 

 

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