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Net-Zero Hotel Relies on All-Electric Systems for Efficiency

Hotel Marcel, a 110,000-square-foot rehabilitation and adaptive reuse of New Haven, Connecticut’s historic Pirelli Building, has raised the bar for sustainable hospitality as the first net-zero hotel in the U.S.

The hospitality industry is huge and continuously growing. However, the booming industry comes with environmental challenges. The Sustainable Hospitality Alliance estimates the hospitality industry produced one percent of annual global carbon dioxide (CO2) emissions, or approximately 364 million tons, in 2021. Fortunately, developers are taking note and up to the challenge, including Bruce Redmond Becker, FAIA, LEED AP, founder and director of Becker and Becker Associates. Becker is the owner, developer and architect behind Hotel Marcel’s transformation.

“The Hotel Marcel building has a legendary past, but it was abandoned for over two decades,” said Becker. “We put together a plan to redevelop this building into a 165-room boutique hotel. In addition to preserving the building as a historic preservation project, we also sought to have it set a new standard for sustainability in the hotel industry.”

While the practical design of the existing structure, with deep-set windows and natural shading, helped to enhance efficiency, Becker and his team had loftier efficiency goals for the building’s revamp. They sought a LEED® Platinum rating and Passive House certification. A 1,000+ panel rooftop solar array and an energy-efficient, all-electric mechanical system helped the team bring their sustainable vision to life.

The pursuit of maximized energy efficiency led Becker’s team to all-electric, all-climate solutions from Mitsubishi Electric Trane HVAC US (METUS).


The Right Systems for the Job

Variable-capacity heating and cooling
A CITY MULTI® air-source Variable Refrigerant Flow (VRF) system from METUS complemented by energy recovery ventilators (ERV), was selected for the hotel’s heating, cooling and ventilation requirements.

With heat recovery and simultaneous heating and cooling capabilities, VRF systems are ideal for hospitality applications where amenity areas, such as indoor pools, fitness centers, restaurants and spas, may require different temperature set points than guest rooms and staff offices. Additionally, the zoning capabilities of VRF systems allow guests to enjoy their rooms at their individual comfort preferences.

“For us, VRF technology solved a big problem by being able to simultaneously heat and cool different spaces in a building,” said James Messenger, project manager at Eastern Mechanical Services, the hotel’s mechanical contractor. “For example, here at Hotel Marcel, one guest room can be in heating mode while another is cooling. It gets you the zoning capability you're looking for and is super quiet, efficient and pretty much runs trouble-free for us. That's the biggest thing we liked about the CITY-MULTI product.”

Introducing Heat2O
Hotel Marcel also marks one of the first installations of Heat2, Mitsubishi Electric’s all-electric solution for commercial, high-volume domestic hot water. The hotel installed three Heat2units totaling 120 kilowatt hours (409,000 BTU) of heating capacity.

“We were delighted to find that Mitsubishi Electric had a commercial scale system for domestic hot water,” said Becker. “The system handles all the domestic hot water needs for the hotel rooms, laundry and kitchen. This technology enabled us to be one of the first, all-electric hotel buildings in the U.S.”

Heat2uses natural CO2 refrigerant with a global warming potential (GWP) of one and an ozone depletion potential (ODP) of zero. The system achieves highly efficient heat exchange using Mitsubishi Electric’s patented Twisted Spiral Gas Cooler where three refrigerant lines are wrapped around a twisted water pipe. Transferring thermal energy from outdoor air to potable water by cycling refrigerant, natural CO2 enables the Heat2system to supply hot water up to 176° F even when outside temperatures are as low as -13° F. Mitsubishi Electric's INVERTER-driven scroll compressor in the heat pump further increases Heat2O’s energy efficiency, providing over four times more energy as heat than the system consumes in electricity.

Heat2is a highly efficient hot water heat pump empowering owners to future-proof their buildings,” said Tom Greco, director, controls applications, METUS. “We want to be clear that Heat2is not just an extension of the traditional hot water heating market. In the right applications, owners can see 60 to 70 percent energy savings over traditional electric resistance hot water systems.”


All roads lead to sustainability
Hotel Marcel is the country’s first net-zero hotel, the first Passive House certified hotel and one of only a dozen LEED Platinum-certified hotels.

“As architects and developers, no one wants to build a building that's going to harm the planet or be responsible for making it less livable for future generations,” explained Becker. “The good news is that's a simple consumer choice. We can buy electric products instead of fossil fuel-based systems. And with the Mitsubishi Electric product, particularly their scalable, commercial domestic hot water system, there's now a solution that enables any building to be all-electric.”

The editorial staff had no role in this post's creation.