OGDENSBURG -- United Helpers recently installed a drain back solar hot water system at their McIntyre Individualized Residential Alternatives facility to reduce costs and cut energy usage.
Equipped with a 120-gallon storage tank for hot water, the building now has three solar collectors on the roof used for heating hot water.
“There is a lot to consider when putting on solar panels such as size of the collectors, panel orientation, temperature, shade, and roof and panel pitch,” said Rick Pirie, Director of Buildings and Grounds at United Helpers.
“Ideally your roof should face south and the panels should be installed a few inches above the roof with enough air flow to cool them down. Since shade is the number one enemy of solar power, the pitch or tilt of your roof and solar panels can affect the sunlight you receive in an average day throughout the year.”
Benefits of the drain back solar hot water system are sustainability, long term efficiency, and incentives, according to United Helpers officials.
The use of solar panels allows a structure to get energy from somewhere other than a main power grid. Therefore, there is no need to run long power lines. Once solar panels are installed, they can make up for their initial installation investment and are very low-maintenance, United Helpers officials say.
There are also a number of federal and government incentives such as NYSERDA that are being offered to those who decide to install solar panels.
Matt Bullwinkle from Sensible Solar in Potsdam was the key component for installation and funding when it came down to United Helpers deciding to go green with a drain back solar hot water system.
“The drain back system used at the McIntyre IRA is durable, scalable to fit a building large or small, works in any climate, will not freeze or boil, is virtually trouble-free, has few parts, and only requires regular maintenance,” said Pirie.
“This system also uses a glycol mix, which has the highest heat transfer characteristics, and it does not have a heat exchanger between the tank and the collectors. With no exchanger between the tank and collectors, the drain back system transfers 100% of the collector heat to the tank.”
Two temperature sensors control the solar system. One is the Hi-temp sensor on the outlet of the collectors. The other is the Lo-temp sensor on the coldest part of the tank.
In the morning when the solar collector temperature rises to about 18 degrees hotter than the tank temperature, the controller turns the collector pump on.
Water is pumped from the bottom of the tank (the coldest part) through the collectors, picking up heat as it goes. The warmed water spills down the return line into the drain back tank.
The process goes on as long as the collectors are at least five degrees hotter than the tank, heating the tank continually. At the end of the day when the difference falls below five degrees, the controller turns the pump off and all the water drains from the collectors back into the tank.