Nova Scotia gets seawater cooling and storage project

(By David Ehrlich) - Alderney Landing is the first project in the world to pair deep seawater cooling with underground storage.

A five building complex on the waterfront in Dartmouth, Nova Scotia, is getting a green retrofit that includes the first pairing of deep seawater cooling with underground thermal energy storage.

Alderney Landing, a 300,000 square foot complex which includes a convention center, art gallery, farmer’s market, and a theater, sits right on the edge of Halifax Harbor, making it a convenient spot for pulling in seawater for a direct cooling system.

But for about eight weeks a year, that seawater is too warm to use for cooling. Halifax-based High Performance Energy Systems is using an underground thermal energy storage system to hold onto some cool seawater for use during those warm months.

The CDN$3 million project is expected to take about a year to complete. The Halifax Regional Municipality, which includes Dartmouth, owns the buildings and is putting up most the money for the project. Natural Resource Canada’s Technology Early Action Measures program is providing CDN$1 million in federal funding.

The project is expected to cut summer cooling costs by 90 percent at the complex, saving the municipality CDN$250,000 per year.

“We have two other construction projects using conventional geothermal designs and are very excited that this one is incorporating 100 percent renewable energy for air conditioning our buildings,” said Mayor Peter Kelly in a statement.

In the Alderney Landing project, when the water in Halifax Harbor is cold enough to serve as a direct cooling source, some of it will be transferred to a borehole field in the complex’s parking lot and stored for use in the summer.

The water is expected to be harvested in January and February for use from late August to the middle of October.

High Performance Energy Systems is drilling 120 boreholes, each about 600 feet deep, for the storage system. The cold energy from the seawater chills the rock mass underground, keeping the water cool until its needed.

This isn’t the first time the company’s worked with water. On the other side of the harbor, High Performance installed a seawater cooling system at Purdy’s Wharf, a two tower office complex also right on the edge of the water.

Purdy’s Wharf uses the system only one and a half months out of the year, but High Performance said the privately owned complex saves about CDN$100,000 a year in energy costs.

The construction at Alderney Landing includes switching from oil to install a high-efficiency central natural gas fired boiler plant, and putting in energy efficient lighting.

The municipality said the project is expected to reduce greenhouse gas emissions by 580 tonnes per year, and allow for the removal of 2,200 pounds of ozone-depleting chlorofluorocarbons, or CFCs, that are currently used to air condition the properties.

“We need energy to power our economy, and we need clean energy to protect our environment - that’s a priority for our government and the foundation of our practical, balanced approach to climate change,” said Gary Lunn, Canada’s minister of natural resources.

“By investing in ground breaking projects like this one, we are making sure that clean, renewable power will form an increasingly important part of our energy mix for the future, in Canada and worldwide.”

High Performance has also installed a black and grey water heat recovery system in Halifax, which recovers heat energy from wastewater and injects it back into the hot water system, saving on hot water bills.

Black water is the term for water from toilets, while gray water is from bathtubs, laundry, and sinks.

The province, which is also looking into tidal power in the Bay of Fundy, expects to generate nearly 20 percent of its electricity from renewable energy by 2013.

Under new regulations this year, Nova Scotia must increase its total renewable supply by five percent by 2010, and 10 percent by 2013.

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