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Thermal Envelope Design Could Save 80 Per Cent on Energy Costs

Nested Thermal Envelope Design

A new concept put forth by two Toronto university professors could see energy consumption in homes reduced by up to 80 per cent during cold winter months.

Russell Richman of Ryerson’s department of architectural science and University of Toronto professor Kim Pressnail have partnered to come up with the idea of Nested Thermal Envelope Design, which heats certain zones in homes.

The professors note that space heating is the largest drain on energy in Canada. By dividing a home into separate zones – perimeter and core – and installing a small heating unit that cycles heat back into the home before it can escape, they estimate energy consumption can be cut drastically.

The duo, working along with U of T Ph.D. candidate Ekaterina Tzekova, noted that heat is often wasted when rooms that are not in use are being heated. Heat is also lost due to leaks or natural cooling from the inclement weather outside.

In the Nested Thermal Envelope Design concept, the house’s “core” consists of the main living areas such as the living room, kitchen and bedrooms. The “perimeter” consists of rarely-used rooms such as a formal dining room or sunroom. They suggest that living exclusively – or as close as possible to exclusively – in the core of a home is akin to shrinking the size of the home itself and can make a huge difference in heating and energy consumption.

The concept calls for a home-within-a-home idea, with the home’s core kept at a comfortable temperature and its perimeter kept considerably cooler. The design employs a heat pump to funnel heat back from the perimeter to the core rather than allowing it to escape.

Nested Thermal Envelope Design

Image Source: sciencedirect

“In the winter, you could get savings by living in a smaller space, period,” Richman said. “But you can’t just heat one room, because there is no insulation between one room and the outside or other rooms. To do it really well, you need to insulate the room and then insulate the whole house. As we explain it, zonal heating is just a house within a house, or a box within a box.”

Richman and Pressnail came across the idea while talking about heat loss in their own homes.

Early simulations of the system show it can result in energy saving of up to 80 per cent. Their theory will be put to the test when the Nested Thermal Envelope Design is tried in a Toronto home this winter.

“The question is, is it worth the additional effort of installing a heat pump? The pump needs to be servicing a lot of energy in order to validate this design,” Richman said. “There are so many research questions to be answered with the house. It’s always exciting to take theoretical research and turn it into practice.”

The trial is expected to last five years, during which time the research team will study the behaviour patterns of – and get feedback from – the inhabitants.

By Anthony Morales
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