Hybrids for the Home

In the basement of a typical 35-year-old home in Boston, a propane-fueled combined heat and power (CHP) system is keeping Alex Stevenson’s family cozy this winter while making enough electricity to cut his winter light bill in half.

The Combined Heat and Power package runs almost silently in a space that is about 6 feet by 6 feet.

Climate Energy, in partnership with Honda and ECR International, developed its micro-CHP system as an alternative to conventional warm-air furnaces in homes. Building on the Honda generator technology that is already in more than 50,000 homes in Japan, Climate Energy’s freewatt system combines two gas-fired technologies – a home furnace and an engine-driven generator – into a hybrid heat and power generation package that lowers home fuel consumption and electricity bills. By recycling the heat from the propane-fueled generator back into the furnace unit, homeowners are able to use the fuel twice to produce power and then to heat their homes.

The freewatt system combines an advanced Honda MCHP engine-generator, a high-efficiency warm-air furnace, heat exchanger module and an Internet-connected control system. Coolant in the system pulls heat away from the engine cylinder head, oil reservoir and catalytic converter to preheat the air entering the furnace. Continuous, base-level heat is delivered at lower fan power to reduce the typical temperature swings and cycling of a conventional warm-air furnace. High-efficiency auxiliary burners kick in on really cold days or if the thermostat is raised.

Climate Energy is the exclusive merchandisers of the Honda engine in the United States.

As the furnace runs, the engine produces 1.2 kilowatts of electric power for the home. Excess electricity can flow back to the grid if home consumption falls below 1.2 kilowatts while the generator operates, providing a credit toward the homeowner’s electric bill. However, only 12 states allow this reflow system, says Eric Guyer, Climate Energy CEO.

Aided by a $25,000 grant from the Propane Education & Research Council (PERC), the first propane units were installed in Stevenson’s 3,200-square-foot home last September for a 12-month field test to monitor run time, efficiency, power and thermal output. The home, which was built as an all-electric residence in 1970 and later converted to fuel oil, uses two furnaces fueled from a 500-gallon underground tank installed by Eastern Propane.

Stevenson, who is director of systems engineering for Climate Energy, says he expects the system to save him $1,000 a year on electricity. Residents in Massachusetts pay 16.60 cents per kilowatthour, based on Energy Information Administration figures from November 2007.

1. Engine; 2. Generator; 3. Catalytic converter; 4. Air filter; 5. Gas/Coolant connections; 6. Inverter and controls; 7. Exhaust mufflers; 8. Flue exhaust port.

If all goes well with the testing, Climate Energy hopes to bring the units to market about this time next year.

To date, hybrid heat and power technology has been limited to larger applications such as industrial and commercial facilities to take advantage of the lower energy costs, reduced emissions and added electricity supply that traditional CHP provides. Engine noise and cost have prevented these packages from being adopted on a smaller scale.

“Improvements in engine technology and cost have enabled our propane-fueled model to become a realistic replacement for the conventional residential heating system in pretty much every home,” says Guyer, who notes that 4 million central heating units are sold every year in the domestic market alone.

Guyer says the system operates at an energy efficiency of 90 percent and is expected to yield a 30 percent reduction in carbon dioxide emissions compared to conventional heating appliances and grid-supplied electricity. Plus, it can slice a homeowner’s monthly electric bills in half during the heating season.

“This is world-changing technology here – using fuel to make electricity and keep warm. Without question, a significant shift is about to commence,” says Guyer, who has been working on cogeneration concepts for 25 years.

Massachusetts-based Climate Energy honed improvements on natural gas versions of the system, which are coming to market in the United States. Fewer than 100 have been sold and are in service.

“We were aware of LPG, of course, but we felt the initial focus should be on natural gas simply because it was a much bigger market,” Guyer explains. “But we also are aware that LPG customers are keen to the savings that this system can provide. Plus, its large rural population and application as a backup power make it a good fit.”

While there are dozens of technologies being tested that use fuel to produce off-grid electricity, Guyer maintains that his company’s product shines in the way the elements are packaged into one simple system that manages both the central heating and cogeneration.

“Anyone could take a lawnmower engine and hook it up to a generator and make electricity,” notes Guyer, who started looking at system options in 2001. “The freewatt is small and light. It’s a plug-and-play installation – nothing exotic. It’s a standard box that you literally just plug into the wall (220-volt) and you are set to go.”

The system controller is connected to the Internet for remote monitoring, control, troubleshooting, diagnostics and maintenance. Homeowners can check on their power savings and program their own thermostat via their freewatt Web page. The homeowner, installing contractor, utility company and Climate Energy are all able to communicate with the system according to their programmed security levels.

Guyer says Climate Energy is developing a pool of certified dealers to install and service its system, which has 20,000 hours warranty on the engine by Honda and five years on parts and service. It also is lobbying the federal government to qualify for tax incentives already available to solar, wind and other alternative fuel systems.

Industry consultant Larry Osgood spearheads an array of cogeneration technology projects being studied and developed by PERC. He likens the freewatt system to tankless water heaters that offer greater efficiency – and subsequent cost savings – to the end users.

The first units will cost $13,000 to $14,000, compared to a standard system that sells for $4,000 to $5,000. That’s too expensive to pique consumer demand except in areas of exceptionally high electric rates – New England, California, Alaska and Hawaii.

“It needs to be cheaper so that higher utilization improves payback,” Osgood says. “But that’s typical for most any technology that first comes on the market. As the prices come down, the market will develop. That’s why we want to begin commercialization as early as possible without putting too much money into it.”

He says the system needs to get down in the $8,000 to $10,000 range for homeowners to realize a two-to three-year return on investment through savings on their electric bill.

“The first laptop computers didn’t fly off the shelf either,” reminds Osgood. “It takes time.”