In March 2009, the Community Environmental Center (CEC) installed solar hot water systems in two multifamily buildings in Brooklyn, New York, as a component of the weatherization of these buildings. Although extremely popular in Europe, thermal solar panels are a relatively untapped source of renewable energy in the United States. Through this project, CEC hoped not only to provide the families living in the apartments with a cheaper energy source, but also to open the gateway for other agencies to use renewable energy as part of their weatherization projects.
“I had learned about solar hot water as an opportunity to save even more than we do with just regular weatherization work in terms of dollars spent on domestic hot water,” said Richard Cherry, Chief Executive Officer of CEC. “But even more important was the idea that we need to use renewable energy wherever we can.”
The panels were installed in two apartment buildings with six units each owned by the Cyprus Hill Development Corporation, a nonprofit community organization that provides housing to low-income families. The buildings were chosen by CEC because they receive plenty of sunlight, are structurally sound, and had already received all other practical weatherization improvements. Another advantage was that the buildings were owned by an enthusiastic nonprofit, which was easier to deal with than commercial landlords.
Because these were the first multifamily solar hot water heater units installed in Brooklyn, there were no records, plans, or precedents to follow. The primary challenge, according to Cherry, was doing research in the area of solar thermal energy. After this initial step, things went smoothly, and so far the project has not only proven to be effective, but also simple. Says Cherry, “Weatherization programs across the country offer a live testing ground for weatherization experiments. More state programs could be taking advantage of this opportunity in their respective communities.”
Fortunately, the CEC had every-thing it needed for this project to work. They had support from the state and the buildings’ owner. The CEC staff was excited about doing something new and groundbreaking. They completed the installation solely with weatherization assistance funding, managing to do the entire project within the bounds of their $6,500-per-unit weatherization grant. Earthkind, a company that has pioneered the introduction of solar thermal systems in New York State, not only supplied the solar panels, but also sent representatives to train CEC contractors to install them.
The solar thermal system works by absorbing the sun’s UV rays to heat propylene glycol in the panels. The heated glycol travels from the roof down to the system’s heat exchanger in the basement. Cold water is pumped to the h
eat exchanger where the glycol heats the water. The hot water is pumped to the storage tanks, ready to be distributed throughout the building. The glycol is then returned to the roof panels to be reheated in a continuous cycle.
Thermal solar panels are much more efficient and versatile than electric photovoltaic solar panels: they work well under less than ideal conditions, operating at 90 percent efficiency even if the panels are not directly facing south or if there is some shadow cover. Generally, from the months of April to October, the system by itself can support an entire building’s hot water needs. During the grayer, shorter days of the winter months, it works together with the traditional water heater system, but is still able to deliver the majority of the building’s needs.
Installation was relatively simple and straightforward. Each system took about three to four days to install from start to finish and required the work of skilled contractors. A plumbing crew was needed to reroute water lines to and from the heat exchanger and storage tank. Plumbing was the only element that needed to be adapted to the new system; everything else stayed the same. Irving Jackson, the lead crew chief chosen from the CEC staff to help spearhead the project, says that this is a project any plumber and contractor could accomplish. The system even comes with a set of instructions and diagrams to ensure proper installation.
“The biggest challenge was bringing it up to the roof. Once it was on the roof, everything else was basically 1-2-3,” said Jackson.
The CEC believes that this project is simple enough that it can easily be replicated. All that’s necessary is the motivation to do so. Says Cherry, “It’s a question of will. It’s something new, so you have to want to do it so you can get the initiative to push your staff to do something different. Once you have that initiative, the people involved got very interested in doing something new.”
The project has been a complete success on all levels. The building owner is already seeing the savings, and after enough time has passed to collect adequate data, the CEC plans to report their success as a kind of blueprint that others can use to follow suit. The CEC hopes that this project will serve as an encouraging example for other weatherization programs. Says Cherry, “I really think it’s time for the weatherization program to look beyond the economics and start saying that there are certain things society needs to have happen. One of them is more renewables.”
Posted on: September 8th, 2011