Hotel Rides Energy Efficiency Wave with Key Cards to Save on Costs

The Aloha Surf Hotel in Waikiki is part of Hawaii’s first boutique hotel chain, Aqua Hotels & Resorts, offering a collection of 15 boutique and budget-friendly hotels in Honolulu and seven Hawaiian resorts on Maui, Kauai, Molokai and Lanai. As part of their commitment to Waikiki’s revitalization efforts, Aqua Hotels has instituted a plan to minimize the hotel’s impact on the environment. The green initiatives include the installation of Green Key Switches, also referred to as “key cards,” in all 204 guestrooms at the Aqua Aloha Surf in Waikiki.
 

Magnum Energy Solutions (MES) provided the energy management solution, which utilizes a key card switch to automatically control both the HVAC and lighting in guest rooms. When a guest enters their room, they place their key card into the switch located inside the entryway, thereby activating the thermostat control unit, bringing it into “occupied” mode. When the guest leaves the room, they remove their key card from the key card switch and both the thermostat and the lights return to energy saving mode. Most rooms also have a battery-free, wireless balcony door sensor. When the balcony door is opened, a signal is sent to the in room HVAC unit, which switches off, until the balcony door is closed.
 

The key card-based energy management system has been in place since January 2012 and the savings are significant. With respect to lighting, the system has resulted in an average of 45 percent energy savings. The energy savings for the HVAC system, which is where the larger load exists, is about 50 percent.
 

During 2011, the significant increase in the cost of fossil fuel caused a corresponding increase in the cost of electricity, particularly for Hawaii, given its isolated geographic location. Hotel owners in Hawaii are now paying about 33.5 cents per kWh, the highest electricity prices in the nation. New York has the second highest average rate at 18.6 cents per kWh.
 

To encourage energy efficiency measures and help hotel owners afford the initial costs of energy management technology, like the solution implemented at the Aloha Surf, Hawaii Energy offers $100 per thermostat installed that allows for guest room thermostat control and which is paired with an occupancy sensor.  This rebate applies to hotels with central AC only. For hotels with split systems or window AC units, like the Aloha Surf, the project becomes a customized rebate, which requires pre- and post-data logging. The Aloha Surf, therefore, received a customized rebate totaling $25,500, which equals $125 per room installed with Magnum’s technology.
 

The core of Magnum’s in-room solution utilizes an innovative EnOcean radio chip. The products based on this technology collect the energy they need for wireless communication from the surrounding environment, using motion, indoor light, or temperature differentials. The principle of energy harvesting enables sensor networks to operate without cables and batteries. Therefore, Magnum’s solution is both wireless and battery-free, which meant a fast installation completed by the hotel’s staff. The team was able to complete about 15 rooms per day, which meant little to no disruption to daily hotel operations -- an important factor for the hotel’s management and facilities team.