In the backdrop of the Glasgow Climate Pact, a renewed global climate agreement, companies and industries have established promising paths to net zero carbon. But what does decarbonization look like in the built environment?
In this video series, Consigli looks at components of net zero carbon construction and implementation with our partners. Our first feature is Hotel Marcel, a certified historic renovation that repositioned a former office building into a hotel, targeting Net Zero Energy, Passive House and LEED Platinum certifications.
Sustainable Energy Production
Looking at operating costs over a five-year period, the investment in net zero operations ultimately pays for itself.
As a net zero energy building, the hotel generates 100% of its own electricity, heat and hot water with a rooftop solar array and solar parking canopies—totaling over 1,000 solar panels—with no fossil fuels used for the building’s power or heat. Hotel Marcel is its own energy island, supported by a battery-equipped solar microgrid to power the hotel, feed power to the grid during peak times and maintain power to the building during grid outages. The building’s Energy Use Intensity (EUI) rating is projected to be 34 kBtu per square foot, which is 80% less energy than median EUI for hotels in the United States.
Building Electrification
Technology, like lighting through an ethernet system, allows what was historically one of the least energy-efficient building operations to greatly reduce energy use and operational costs.
Hotel Marcel houses all-electric kitchen and laundry facilities—some of the largest energy-use areas in hotel operations—and utilizes low-voltage Power over Ethernet (PoE) technology to significantly reduce energy use across the entire building. Building-wide PoE powers and controls all lighting and window shades, enhancing operational control and reducing lighting energy use by over 30% compared to conventional lighting systems.
High-efficiency Mechanical Systems
The right mechanical systems can reduce monthly heating and cooling expenses while fostering improved indoor environments through ventilation and exhaust air heat transfer without direct air mixing.
Carefully selected mechanical systems at Hotel Marcel, specifically Variable Refrigerant Flow (VRF) air-source heat pumps and Energy Recovery Ventilation (ERV), support energy-efficient heat recovery and improved indoor air quality in the hotel. The VRF systems at Hotel Marcel can recover heat from cooled spaces for use in heated spaces and vice versa, enabling multiple indoor zones to operate on the same system from the same main compressor unit. The ERV recycles heat energy from the building’s exhaust air to pretreat outside air, reducing load on the HVAC unit and the required capacity of the mechanical equipment. ERV operations are essential for achieving great indoor air quality in high-performance, airtight buildings like Hotel Marcel.
Airtight Envelope Design & Moisture Control
Historic restorations requirements and regulations are not an end-stop for sustainable construction. Innovative building strategies can maintain a building’s historic integrity and deliver solutions for a more sustainable future.
Key to an energy efficient building is a well-insulated envelope with interior and exterior insulation, especially when targeting Passive House. However, at Hotel Marcel, the historic concrete façade could not be modified. Through interior spray foam insulation, the project team created an airtight, high-performance envelope while leaving the exterior untouched, aside from minor caulking improvements. Great care was taken in selecting an environmentally preferable spray foam with low embodied carbon and minimal off-gassing. Coupled with the installation of high-performance window, multiple layers of spray foam insulation ensure an airtight envelope protected from the impacts of outdoor moisture.