CONSTRUCTION INNOVATION, Winter 2002

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To assist manufacturers in developing and evaluating cogeneration systems, the Canadian Centre for Housing Technology has made changes to both its test and reference houses.

Cogeneration, or "cogen," usually refers to industrial processes, such as the combustion of residues from the fabrication of pulp and paper, in which waste heat is recovered to generate steam, which can in turn be used to produce electricity. It can also refer to systems that generate electricity as the primary output, such as micro-turbines and fuel cells, in which heat from the process is used to produce additional power or to heat water and buildings.

Small cogeneration plants may be a viable alternative to large and expensive power generating stations in some circumstances: electricity is produced where it is needed, heat recovery boosts efficiency, and emissions can be reduced by using clean fuel sources.

Events like the 1998 Ice Storm in Eastern Canada and the recent rolling brownouts in California have increased homeowners' interest in small power plants that can provide primary or back-up power for their houses. New and remote communities not yet connected to the power grid are also looking at this option.

Manufacturers in Canada and many other countries realize that there are market opportunities in such technologies and they have been busy developing cogen systems for residential applications. Machines ranging in size from 1 to 5 kWh are capable of providing all or part of the electricity and heat required by a typical Canadian household.

Some systems are intended for houses connected to the power grid, so that for periods of peak power consumption additional electricity can be obtained from the utility, while others are intended for houses not connected to the power grid and thus require battery backup to handle peak demands. Waste heat produced when generating electricity can be recovered to meet the space and water heating needs of the household.

Changes made to CCHT houses
Wiring changes have recently been made to the CCHT test and reference houses so that cogeneration systems, such as fuel cells, can be installed, evaluated and compared. These changes allow all normal house circuits to be fed by a cogen system. The control room and devices simulating internal heat gains from human activity, however, remain on-grid because they are not standard features of a house. New meters 1,667 times more accurate than the previous ones are able to characterize the electrical consumption of the houses for each five minutes of a 24-hour period.

NEW METERS AT CCHT ARE ABLE TO CHARACTERIZE THE ELECTRICAL CONSUMPTION OF THE HOUSES FOR EACH FIVE MINUTES OF A 24-HOUR PERIOD

Both houses are equipped with state-of-the-art power quality meters, which monitor and analyze the power quality delivered by the cogen system in one house and compare it to that delivered by the utility in the other house. It is important to know whether the power quality (which refers to characteristics such as fluctuation and reliability) generated by the cogen system is as good as that from the utility, as poor quality power can negatively affect such things as computers and health monitoring equipment.

The way in which electricity is currently being delivered and distributed in each house permits the use of off-grid systems and, with some modifications, it will be possible to connect systems that are designed to operate on-grid.

In order to make use of recovered heat, each cogen system will have to be customized to meet the space and water heating needs of the house. With only minor changes required, water heaters and air handlers in the test house could be adapted for heat-recovery purposes.

Testing and commissioning of the CCHT houses in cogen-mode are expected to be completed by the spring, which means that the evaluation of commercial systems could start as early as July.

Specific questions about the CCHT cogen-ready houses can be directed to Mr. Luc Saint-Martin at (613) 991-0960, fax (613) 991-0976, or e-mail luc.saint-martin@nrc-cnrc.gc.ca.

The Canadian Centre for Housing Technology (CCHT), a joint venture of the National Research Council, Canada Mortgage and Housing Corporation and Natural Resources Canada, was created to assist Canadian manufacturers in developing new technologies and getting them to market.

CCHT has two research houses, a reference house and a test house, that are side by side and identical in orientation, size and construction. Both houses are fully instrumented and use automated controls to simulate human activity. The reference house serves as a control unit while the test house can be modified according to research requirements.

TWIN RESEARCH HOUSES AT THE CANADIAN CENTRE FOR HOUSING TECHNOLOGY

For more information about CCHT, see Construction Innovation, Winter 2000 or visit http://www.ccht-cctr.gc.ca.