Canadian Consulting Engineer

Gimli Community Health Centre

October 1, 2007
By Canadian Consulting Engineer

In May 2004, the Gimli Community Health Centre opened its doors, becoming the most energy efficient hospital ever built in Manitoba and one of the most efficient in Canada.

In May 2004, the Gimli Community Health Centre opened its doors, becoming the most energy efficient hospital ever built in Manitoba and one of the most efficient in Canada.

All the cooling and about 25% of the heating in the centre is achieved by ground water. There are no chillers, heat pumps or condensing units with their inherent high electrical consumption and environmentally hazardous refrigerants. In fact a 100-ton chiller, two chilled water and two condenser water pumps in the original building were replaced by a single 15 Hp submersible well pump.

The hospital serves the town of Gimli and the surrounding rural and vacation communities on the southern shores of Lake Winnipeg.

An original hospital on the site from the 1930s was deconstructed and converted to a healing garden. However, the existing 2,415-sq.m Johnson Memorial Hospital built in 1970 was redeveloped and incorporated into the new centre. The result is a 4,877-sq.m, steel frame, one-storey structure. It includes ambulatory care and diagnostic services, a clinic with 28 inpatient beds, and an expanded emergency department. There are also palliative care, chemotherapy, physiotherapy, occupational therapy, a pharmacy and other support services.

Engineers offered the sustainable alternative

The design of hospitals in Manitoba typically followed a “cookie cutter” approach that did not include any additional expenditure for energy conservation. Manitoba Health, the provincial funding authority, had a fixed budget and was skeptical that an energy efficient design could be achieved without significant additional cost.

MCW/AGE believed so strongly that this was not the case, that the firm undertook a second, parallel, energy efficient design, at its own expense. Both the efficient design and the traditional approach were analyzed by third party quantity surveyors and it was determined that the energy-efficient design actually would cost slightly less. The Interlake Regional Health Authority were strong supporters of the parallel design and approved it.

The expansion and renovation doubled the size of the facility, added ventilation air to areas that were previously far below current code levels, and created a non-institutional healing environment with improved lighting and thermal comfort. The building systems are so efficient that the new building consumes 19% less natural gas, and only 18% more electricity than the original facility, even though the new complex is twice the size.

Open well geothermal systems

The hospital incorporates an open well form of geothermal heating and cooling. There are no heat pumps; rather the ground water is used to cool the building directly by being pumped through the air-handling unit cooling coils.

While this geothermal system cools the building, it also warms the ground slightly in the summer. MCW/AGE did not want any unnecessary environmental impact, so a system was designed for the 7.2C ground water to warm a glycol ventilation pre-heating system in the winter, which in turn removed the summer heat from the ground. The glycol is pumped into pre-heating coils on each air handling unit, enabling the outside air to be heated from -35C to -8C. This system seasonally thermally balances the geothermal loop, and it also allowed the designers to reduce the capacity of the boiler by 25%. It reduces greenhouse gas emissions by 140,000 tons annually.

Using direct well water for cooling air had been done previously on occasion in Manitoba, but there had been some high-profile failures. MCW/AGE spent considerable time reviewing existing open well systems and used the lessons to guide their design, particularly in avoiding premature heating of the ground water, and in selecting materials.

MCW/AGE were the first to use the geothermal technology to pre-heat ventilation air from outside. A hospital provides a unique opportunity for preheating outside air because the code requires very large quantities of ventilation air, while traditional air-to-air heat recovery ventilators cannot be used in order to avoid cross contamination.

To meet the Manitoba Conservation regulation that requires the temperature difference between supply and injection wells be not more than 5C, the engineers recommended a variable frequency drive for the well pump and two-way control valves on the cooling coils in the air handling units. The coils were sized to accommodate the maximum temperature differential as well as to accommodate a 1C increase in average ground water temperatures over the course of a summer.

Brackish water in the wells

Two test wells were drilled for the project and these became the permanent water supply and return wells for the hospital. Nearby municipal wells that draw from the same aquifer indicated that the water was brackish and contained significant dissolved solids such as calcium and iron. Because budget constraints prohibited prefiltering the ground water, each of the cooling coils in the air handling units was designed with a permanent periodic cleaning system in order to prevent dissolved solids precipitating onto the inside walls of the coils.

As subconsultant to the architect, LM Architectural Group, MCW/AGE provided all the mechanical and electrical design services from concept through construction administration. Close liaison with the architects resulted in the building having energy efficient features such as “low-E” windows, enhanced wall and roof insulation, as well as the energy efficient mechanical-electrical systems.CCE

Name of project: Gimli Community Health Centre, Gimli, Man.

Award-winning firm/mechanical and electrical subconsultants: MCW/AGE Consulting Professional Engineers, Winnipeg (Steve Reaburn, P.Eng., Elliott Garfinkel, P.Eng., Curtis Dahl, William Wright, Dave Jackman)

Client: LM Architectural Group

Owner: Interlake Regional Health Authority

Suppliers: Barcol Controls (controls)


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