Mount Sinai Hospital goes greener and gets cooler with new energy source

Toronto’s Mount Sinai Hospital is getting greener and going deeper beginning in spring 2009.

The hospital signed on with the Enwave Energy Corporation (Enwave) Deep Cooling program, which will enable Mount Sinai to reach into the depths of Lake Ontario for an environmentally-friendly air-conditioning source for its facility.

“Deep lake cooling has become an international phenomenon,” explains Altaf Stationwala, Senior Vice President of Operations and Capital Redevelopment at Mount Sinai Hospital. “Other Toronto hospitals are using Enwave; however, Mount Sinai is the only acute academic health science centre in Toronto that is exclusively using the technology as its cooling source.”

Enwave’s technology currently provides more than 140 buildings in downtown Toronto with the cooling source through an underground piping distribution network. Mount Sinai is in the process of creating its own infrastructure to connect with Enwave’s distribution grid. The company’s pipes draw ice-cold water (approximately 4ºC) from 83 metres below the surface of Lake Ontario and carry it to the Toronto Island Filtration Plant. The cold water is processed and then sent to the John Street Pumping Station where heat exchangers carry out the energy transfer between the cold lake water and the Enwave closed underground chilled water supply loop. Mount Sinai will connect to this loop to get the energy to air condition its main building.

“Enwave aligns perfectly with Mount Sinai’s push to be greener,” says Simon Stengs, Director of Building Services at Mount Sinai Hospital. “With Enwave we will reduce the hospital’s electricity use for cooling the building by 90 per cent and we will no longer need the conventional air conditioners, transformers, fans and cooling towers resulting in a reduction of noise, pollution and humidity levels.”

Mount Sinai’s participation in Enwave is helping reduce Toronto’s carbon footprint. It will help free more than 61 megawatts from the city’s electrical grid, which is equivalent to the amount needed to supply energy to 6,800 homes annually. The hospital’s involvement will also contribute to the prevention of more than 79,000 tons of carbon dioxide being released in the atmosphere each year, which is comparable to removing 15,800 cars off the road.

Helping the environment isn’t the only benefit Mount Sinai considered when making the decision to enrol with Enwave. This realization came recently when Mount Sinai’s conventional chiller was due to be replaced. When Stationwala and his team looked at the cost of a new conventional system and the investment in Enwave, the business case was clear. A 20-year forecast shows that energy costs using chillers will reach $13.5 million whereas the cost of using Enwave is $10 million – an accumulated cost savings of $3.5 million that Stationwala explains will be put back into patient care. The pipes needed to connect Mount Sinai with the Enwave system have a long lifespan and are a one-time investment.

“The environmental impact and cost savings of deep water cooling made the decision to sign on with Enwave clear,” says Stationwala. “We have a duty to our patients, their families, our stakeholders and community to be environmentally and fiscally responsible. At Mount Sinai, we’re making greater efforts to go green and Enwave is a big part of our strategy.”