Sold on Solar Hot Water
A version of the article below by Kerstin Muth was originally published in the Chronicle Journal on October 31, 2014. Click here for a link to the CanSIA document "Solar Heat, Sustainable Future: Clean Energy Solutions for Canada"
The daylight hours are slowly diminishing at this time of year but that doesn’t mean the sun is setting on solar energy.
This month Environment North features two personal accounts of residential solar thermal hot water heaters (see links below to their full stories). A typical residential solar hot water system consists of solar collectors installed on a south- facing roof, some tubing and a heat exchanger to transfer heat to a water storage tank. Non-toxic food-grade glycol, which will not freeze in the winter, is heated in the collector panels by the sun and is pumped through the system. The heat from the sun-warmed glycol is transferred to a water tank.
Click here for Scott Harris' full story.
Click here for Susan Grinstead's full story.
Three years ago, Environment North board member Scott Harris and his wife Helen had a flat panel solar hot water system installed at their home in Thunder Bay. The small motor that runs the pump is barely audible. The system has been very low maintenance. Every three years the glycol is replaced – this supplier-assisted task takes about one hour.
This system provides them with most of the hot water they need for about 8-9 months of the year. They have natural gas as a backup to provide some additional heating in the coldest winter months. Scott is a self-described “sun-worshipper”. They also have a small solar-electric system at their camp to run the lights, the radio and some other small electronic devices.
Susan Grinstead is a big fan of solar energy. A greenhouse has been providing significant passive solar heat to their home for many years. Two years ago she and her husband Maurice also installed a solar hot-water system. The solar-hot water system pre-heats the water in a tank before it is used by their heat-on-demand system. In the spring, summer and fall, it easily reaches 72°C. In the winter, the tank temperature averages 30-35°C and back-up natural gas is needed.
Solar hot water systems need to be fine-tuned to their location and to the lifestyle of the residents. Consider just one aspect, the angle of the collector panels. Susan had the panels set permanently at an angle of 63°. Panels set near this angle will capture the sun’s energy best during the winter when the sun is lower in the sky and they will also shed snow better. She knew that she was never going to climb up onto the roof of their 1½ storey home to clear the snow away or change the angle.
Scott is contemplating changing the angle of his panels to be steeper like Susan’s. Of course, if either Scott or Susan were snow-birds and not home during the winter they would consider a different panel angle for better efficiency of the system during the warmer seasons.
There are two basic types of solar hot water collectors, flat panel collectors or vacuum tube collectors. However, there are other options such as a combination photovoltaic thermal panel. These systems take excess heat from photovoltaic or solar electric panels and transfer this heat to a water heater.
There is perhaps no best system for all but rather a best system for a particular family or business. A home energy analysis is one of the best ways to find out how to reduce energy consumption such as more insulation, a more efficient furnace or renewable energy options.
A key reason that both Scott and Susan have solar hot water heaters is to help protect the climate by reducing their personal greenhouse gas emissions. According to Scott his investments are paying both “monetary and mental dividends”.
Around the world China generates the most solar thermal energy. On a per capita basis Cypress is first, Israel second, Austria third, Germany eighth and Canada, which has more sunshine than Germany, is 33rd. Unlike many other countries Canada is currently lacking a national policy, program or target for solar thermal energy. A few years ago, many businesses and individuals, including Scott and Susan, were able to reduce capital costs by taking advantage of the now discontinued government incentives.
Kerstin Muth is a member of Environment North