Bruce Redman Becker, president of Becker and Becker Associates, put together a plan to redevelop this building into a 165-room boutique hotel, with the goals of preserving the historic building and setting a new standard for hotel sustainability.

A City Multi air-source VRF system from Mitsubishi Electric Trane HVAC US, complemented by energy recovery ventilators, was selected for the hotel’s HVAC requirements. With heat recovery and simultaneous heating and cooling capabilities, VRF systems are ideal for hospitality applications where restaurants and other amenity areas may require different temperature set points than guest rooms and staff offices. One guest room can be in heating mode while another is cooling.

For hot water, the hotel installed three Heat2O units — Mitsubishi Electric’s all-electric solution for commercial, high-volume domestic hot water — totaling 120 kilowatts (409,000 BTU/H) of heating capacity. The system handles all the domestic hot water needs for the hotel rooms, laundry, and kitchen. This technology enabled Hotel Marcel to be one of the first all-electric hotel buildings in the U.S.

Heat2O uses natural CO₂ refrigerant with a GWP of 1 and an ozone depletion potential 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 CO₂ refrigerant, the Heat2O system supplies 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.

The Heat2O water system and City Multi VRF system are controlled by Mitsubishi Electric’s customized Diamond Controls solution. It’s a singular platform and everything is funneled up to the cloud, allowing building management to monitor efficiencies and respond quickly to any fluctuations in energy usage. Heat2O can receive signals from grid operators and facilitate participation in utility demand-response programs. In advance of demand-response events, the system runs in capacity mode to preload tanks and provide occupants with uninterrupted access to hot water. Then, when the demand-response signal comes, it sends set points to the VRF and Heat2O systems to reduce energy usage and hit the hotel’s net-zero requirements.

Along with the hotel’s efficient, all-electric mechanical system, the practical design of the structure itself — with deep-set windows and natural shading — served to enhance efficiency, while a 1,000+ panel solar array on the parking canopies helped the team realize its sustainability vision. Hotel Marcel enjoys a projected energy use intensity of 80% less than the median U.S. hotel.