Solar hot water system reduces total energy costs by 30%

The majority of hot water use is the Big Wave Café’s dishwasher – up to 400 Litres a day during the summer! So much, in fact, that the cost of heating water in tourist season nearly equals the cost of heating the entire building in the winter. The solar water-heating system will reduce this cost by at least 30% and as much as 60%.

An ecoENERGY rebate reduced the cost by $2300 (or 25% of the total); and a Conserve Nova Scotia rebate further reduced the cost by $1300 (or 15% of the total). The rebates – totalling 40% or $3700 – helped bring the cost down to approximately $5500, which was paid for by a development grant from the Nova Scotia government. For more info about programs, rebates, and other grants, visit conservens.ca or call 1-800-670-4636.

The system was supplied by Thermo Dynamics in Dartmouth, NS; and was installed by John Ross, of Sun Ross Energy in Cleveland, Cape Breton.

How it works

Solar ‘collectors’ installed on the south-facing wall of the building absorb sunlight and convert it to heat, which is transferred to a water/glycol solution (basically anti-freeze) running through copper tubing in the panels.

A solar-powered pump circulates the fluid through a coil in the ‘solar boiler’ in the furnace room, where the heat is transferred from the fluid to the water in the boiler. The heated water in the boiler is transferred to a secondary tank, where it waits until someone turns on the taps or runs the dishwasher. The ‘solar fluid’ loops back into the solar collectors and does it all over again.

Tips for inexpensive/free water heating savings:

Showering typically accounts for 1/3 of water heating: start by installing a low-flow shower head. These reduce shower water usage by about 50%… without affecting comfort. Oh, and take shorter showers.

Washing clothes typically accounts for 1/4 of water heating – but most clothes wash just as well in cold water. Use the cold/cold cycle instead of hot/warm and reduce the energy used per load by a whopping 90%.

Water heaters are typically set around 60°C. On oil or gas water heaters, lower the temperature to 49°C, sufficient for most homes’ needs, and wrap your water heater in an insulation blanket. (Electric water heaters should stay at 60°, due to the risk of legionnaire’s disease.)

Posted by Mike Targett | Email a comment