OUR UNIQUE NET ZERO APPROACH
Our Optimal solution selection strategy consist of laying out all possible design options for the three main disciplines (Architectural, Mechanical and Electrical), Calculating the Initial cost (project cost) and running cost (Operation and Maintenance) for each design option, feeding options costs to our sophisticated Excel Model and using Tools such as Solver and Crystal Ball for choosing the most optimal design portfolio.
We won't be sharing our Excel Model in this article due to the complexity of the model as as well as the intellectual property right owned by our team of professionals (Engineers and Architects).
For the mechanical discipline, we evaluated several options among them geothermal energy, Solar Water Heating, Solar Air Heating, Air and Water Heat Recovery and many other options.
For the Architectural discipline, we evaluated the options of having several level of envelope energy efficiency ranging from the minimum required by the applicable Building Code to the passive houses level.
Same thinking was done for the electrical discipline, such as Photovoltaique Solar Panels, Heated Glass, etc....
Architectural and Mechanical Selected Options
We will be presenting the mechanical and architectural optimal options together since building thermal properties and architectural features (such as solar orientation, thermal efficiency, envelope tightness level, solar overhangs, etc...) determine building overall thermal efficiency which influence the selection of the Building HVAC and Plumbing System.
Optimal Architectural and mechanical systems Portfolio are the followings:
|Architectural Component||Thermodynamic Properties of Components|
|Slab on Grade||Insulated Slab with R25 (IP) thermal insulation|
|External Walls||Insulated with R30 (IP) thermal insulation|
|Roof||Flat Roof With R50 (IP) Thermal Insulation|
|Windows||Double Glazing With U Value of 0.15 (IP) and SHGC of 0.19-0.39|
|South Facing Fenestration Passive Heating/Cooling||2.5 Feet of horizontal overhang above windows and doors|
|East Facing Fenestration Passive Heating/Cooling||0.8 Feet of horizontal overhang above windows and doors|
|West Facing Fenestration Passive Heating/Cooling||0.8 Feet of horizontal overhang above windows and doors|
During our load calculation and energy simulation process, we noticed that marginal winter heat loss becomes non significant when Envelope component's (Wall, Slab, Partition, etc...) thermal insulation exceeds certain value (Optimal Value) but marginal cost increases exponentially for thermally insulated components above the optimal value.
For a slab on grade house, Winter Heat losses with an R7.5 (Canada Building Code Minimum Requirements) Styrofoam insulation underneath the slab is 2,754 Btu/hr. Heat loss decreases to 1,378 with an R25 Insulation (by 50%). Heat loss value decreases to 1,216 Btu/hr (by 61%) with an R30 Slab Insulation. The marginal cost between R25 and R30 insulation exceeds the marginal benefits for the whole Project's life cycle .
Same logic was used to determine optimal thermal resistance value for Walls, Roof and Windows. We specified the most energy efficient double glazing window available in the Canadian Market (U Value of 0.15 (IP)), which remains cheaper than triple glazing windows having similar thermal caracteristics.