EnOcean HVAC Controls Neutralize Highest Electricity Rate in the United States

September 22, 2009 – San Ramon, CA

The EnOcean Alliance and two of its 120 members, Echoflex Solutions and Illumra, combined to take on high energy prices in Hawaii. The solution for Kahana Falls hotel was discovered on the demand side of energy management. By automating the amounts of conditioned air entering hotel guest rooms according to the Open/Closed status of patio doors and the occupancy status of each room; the hotel immediately reduced energy consumption and subsequently stood to buy back revenues lost to wasted energy. Hotel management saw the merits of automating hotel room climate control and integrated a transformational HVAC control system. The keys to the transformation were energy harvesting wireless sensors and switches that provided simple means of retrofitting the hotel with automated demand-side energy management. Factoring energy savings and government rebates versus the cost of installation, the new wireless system figures to pay for itself in eight months.

It’s not all sun and games for hotel owners in Hawaii. In addition to dealing with an ailing economy, hotel owners in Hawaii are forced to factor the nation’s highest electricity rates into their accounting spreadsheets. According to the US Department of Energy, the base cost of electricity in Hawaii weighs in at a staggering $0.30/kWh rate (nearly 3x the national average). The high cost is attributed to the fact that in Hawaii, power is produced by burning imported fuel.

Rather than rest idle and allow the cost of electricity to consume profits; Kahana Falls management set out to save money while concurrently conserving their state’s natural resources. The solution was to install energy harvesting wireless HVAC controls into each hotel room. The energy management system has halted energy waste in unoccupied rooms while contributing to the fight against CO2 emissions.

Demand-Side Energy Management

Sensor-driven: If a guest leaves a patio door opened; after a specified amount of time, a door sensor sends a radio signal that automatically turns off the A/C unit.

Occupancy-based: When guests take removes their key card from its dock and leave the room, the air-conditioning unit is automatically turned off.

Challenges Faced, Problems Solved

With environmental and economical paybacks already in sight, the team installed the energy management system and was able to minimize hotel closures due to the fact that wiring obstacles were averted. Below is a list of installation challenges and their counter solutions:

95% Occupancy Rate: Because almost all the hotel rooms are reserved, room closures are costly. If the same solution was installed using wired sensors and switches, the cost of closures would have superseded project benefits. >> Solution > “Peel-&-stick” wireless sensors & switches enabled fast installations and revenue was not lost to room closures.
Concrete Divider Walls: The retro-fit installation posed hard-to-wire locations such as concrete divider walls and ceilings. >> Solution > The controls operate free of batteries and wires – the solution rescued installers from having to spend time digging into walls and ceilings.
Zero-maintenance: Project specifications required the controls operate maintenance-free. >> Solution > The controls operate without batteries and will require zero-maintenance over the long life span of the controls (20+ years).
CO2 Emissions: CO2 contributes to environmental degradation. >> Solution > Factoring a 20% reduction in room energy use; 319,000 pounds of CO2 will be saved each year due to the hotel’s energy savings.