Volume 25, number 1, June 2011

Constructing tomorrow’s building – today!

The building design and construction sectors are currently running flat out. The demand for efficient, green buildings has been rising constantly in recent years. The LEED standards, for example, have defined a framework for sustainable development that offers increased comfort for the occupants while optimizing the building’s energy performance.

Another movement now on the market is the emergence of energy systems for communities (urban heating), often called a Smart Energy Grid. The Canadian Gas Association organized a workshop on the technological future of natural gas in February 2010, and this subject captured the attention of the participants.

What are energy systems for communities?

They are thermal networks emanating from a central distribution point, the thermal power plant, which supplies several buildings with hot and cold water systems, among others. Several sources of energy can be integrated to supply the thermal power plant, for example, natural gas, biomethane, solar power, geothermal energy, biomass and cogeneration.

How will building receptors have to be designed to integrate these new sources of energy?

Buildings linked to an energy system for communities will have to have their own internal energy distribution system. Water is an excellent heat transfer medium to meet the needs for heating, domestic hot water and ventilation, for example. The concept calls for a more global than individual approach.

In the case, for example, of an apartment or condo building, the classic approach is to install individual water heaters with peripheral heating in each unit, as well as a fresh air intake system in order to meet the requirements of the National Building Code. Integrating an urban heating concept is thus difficult.

More and more, we are seeing hot water circulating systems that supply each unit for heating and ventilation. The hot water is often produced centrally. The heating system is hot air, integrated with an air intake with a heat recovery ventilator for each apartment or condo.

Today’s buildings are designed to minimize heat loss through the building envelope and windows. With a well-designed hot air system, a comfortable environment can be achieved without the need for peripheral heating.

How does the energy bill get divided?

In Europe, it is common to divide the load for heating and domestic hot water with the help of energy meters. This approach is coming to Canada and Measures Canada is establishing a framework for its use.

Energy systems for communities have several advantages:

  • Space gain in units and smaller mechanical rooms in buildings.
  • Reduced capital and maintenance costs.
  • Increased efficiency in heating and in producing domestic hot water due to a better utilization factor. This leads to a reduction in greenhouse gas emissions and, most of all, increases flexibility since different energy sources can be used.

Future energy distribution system

Marc Beauchemin, Eng. CEM