Cold Air Distribution for Passive House Innovation -
Sustainable Cooling Solution

Section 1: Ensuring CAD performance and reliability in real projects.

Phase 2 takes CAD from concept to application, with a focus on:

• Implementing CAD systems in projects across Canada
• Rigorously testing materials and assemblies
• Identifying solutions that ensure airtightness, durability, and condensation control

This work helps validate CAD as a dependable strategy for high-performance buildings.

Section 2: The Ductwork Story

Solving condensation, airtightness, and durability challenges.
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Our Phase 2 work dug deep into ductwork design, because delivering cold air efficiently depends on more than just theory. We tested, fabricated, and refined solutions to tackle real-world risks:

• Preventing condensation with insulated duct systems
• Ensuring airtightness through tape, sealing, and fabrication methods
• Addressing material choices, cut ends, and custom diffuser design
• Balancing durability with ease of installation

These lessons helped shape ductwork strategies that can reliably deliver CAD performance in the field.

Section 3: Ductwork Performance

Why heat transfer and airtightness matter.
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After airtightness testing, we turned to ductwork performance,  looking at how heat gain impacts CAD systems in practice. Our testing revealed critical factors for scaling CAD confidently:

• Heat transfer directly affects comfort and energy efficiency
• Systematic testing uncovered the link between airtightness and heat gain
• Precise measurements showed why duct length and sensor placement are critical
• Lab findings were translated into real-world installations to reduce project risks

These insights guide better design, installation, and performance for CAD, setting the stage for the next phase: cooling coil evaluation.

Cooling Coil Performance

Can the coil actually deliver 5°C air?

‍Once we knew how much temperature the ducts lose, we turned to the coil itself. Manufacturer data was too limited to confirm it could hit our target, so we tested it independently. Our focus:
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• Why 5°C is the benchmark: water just above freezing, about 2°C, avoids frost on the fins
• Building our own test setup and making our own chilled water, from ice packs to a compact chiller
• A puzzling result: 2°C water, but outlet air closer to 8°C
  
• The discovery: air bypassing the coil through gaps inside the casing, solved by sealing

Component-level airtightness matters as much as system-level airtightness. Next up: finding a heat pump that could deliver everything we needed.

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Heat Pump Sourcing & Performance

Finding the only heat pump that could meet CAD's demands -
and whether it would actually work

CAD needs one heat pump to make 2°C chilled water and high-temperature domestic hot water at the same time. Most of the market couldn’t do it. Our focus:
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• Why this was a physics problem, not a budget problem
• The performance triangle: temperature range, efficiency, and cold climate performance
• R290, a propane refrigerant (not a fuel), and why it unlocked both extremes
• A European-designed unit with extrapolated cold climate data, not field-tested Canadian data

Designing CAD into Real Buildings

Every component had to earn its place.
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CAD has no standard spec sheet, so we went back to first principles and justified every decision with the numbers. Our focus:
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• Why conventional load calculations overestimate a passive house
• Reconciling our numbers with the mechanical engineer’s before sizing equipment
• Right-sizing the heat pump and the tanks that follow it
• Less equipment in the suite, with more coordination up front with the architect

These lessons shaped the system that follows: how it operates once it’s built.

Zone-Level Intelligence in Cold Air Distribution

How each suite thinks for itself.
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Every suite operates as its own system, and one controller manages it. In this carousel, we cover:
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• The staged heating and cooling sequence: water first, airflow second
• Why ventilation boost is not simple with a central ERV, and how VAV dampers solve it
• A custom thermostat developed with Swegon, the ERV manufacturer
• CO2 sensing, a boost button, and a CT switch that detects range hood use

Next up: the hydronic design behind it all.

Inside the Hydronic Loop

Supercooled air needs supercooled water.
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Delivering 2°C water to the coil is a fluid mechanics problem, not just a temperature problem. We follow the loop from heat pump to suite:Every suite operates as its own system, and one controller manages it. In this carousel, we cover:
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• Glycol for freeze protection, and its cost in flow and pump power
• A heat exchanger that keeps 50% glycol out of the building loop
• Pressure loss and the challenge of selecting circulators
• A three-pipe buffer tank arrangement that sends the coldest water to the coils

Every degree is paid for somewhere in the system.

Next: the intelligence that runs it.