The Honda MCHP unit uses an advanced natural gas-powered internal combustion engine to drive a permanent magnet generator to produce high frequency AC electric power. The high frequency power is converted to standard 60 Hz AC power by its solid-state inverter.

A partnership between Honda and Climate Energy has yielded a hybrid home heating system that both heats the home and generates electricity at the same time. It is the first of its kind to be introduced in the U.S., and meets all of the technical criteria to attach to an electric grid.

The Climate Energy Micro-CHP system (patent pending) uses an advanced natural gas-powered internal combustion engine from Honda to drive a permanent magnet generator, which efficiently produces high frequency AC electric power. The high frequency power is converted to standard 60 Hz AC power by a solid-state inverter, allowing the power produced to be fed back to the electric grid to provide an economic credit for the homeowner. Heat is released by the engine-generator as it produces electric power. The hybrid system allows the heat to be transferred to the warm-air heating system, where it is ultimately supplied to the home. By combining the furnace and engine generator components, the system is able to use the heat twice — first to produce the electric power, and then to heat the home.

The furnace is a high efficiency warm-air unit that uses an Electronically Commutated AC motor to provide efficient variable speed blower operation.

The Climate Energy Micro-CHP system provides about 50 percent of a typical residential customer’s annual electric need, according to Climate Energy CEO Eric Guyer, producing on average 4,500 kW a year. The system operates with 95 percent AFUE furnace heating efficiency, and the Honda MCHP Unit provides an overall heat and power efficiency of more than 85 percent, decreasing operating costs.

The system provides significant energy savings, especially during the winter months for homeowners residing in areas that experience harsh temperature drops — up to $600 for those homeowners annually. The Climate Energy Micro-CHP system is not an auxiliary heater, instead it heats the entire dwelling and will be marketed as a new or replacement system.

The system is comprised of four components:

Honda MCHP Unit. Includes the engine-generator and inverter components. This component produces 1.2 kW of electric power and 3.25 kW of useful heat.

Furnace. A high efficiency condensing warm-air furnace that utilizes an Electronically Commutated AC Motor to provide efficient variable speed blower operation.

Cogen Heat Module. Includes the equipment needed to circulate coolant from the engine to an air coil that heats the return air to the furnace.

Supervisory Control System. Uses data from the communicating thermostat and outdoor temperature sensor along with digital data from the MCHP unit to determine how best to operate the Micro-CHP system for maximum comfort and economy. The Honda M-CHP system is connected to the Internet for remote monitoring control, troubleshooting, diagnostics and service messages.

The technology is geared toward consumers in more than 35 states that have “net metering” policies. Net metering enables customers to use the electricity they generate to offset their consumption over a billing period by allowing their electric meters to turn backward when they generate electricity in excess of their demand. The offset means that customers receive retail prices for the excess electricity they generate. Net metering also allows customers to “bank” their energy and use it at a different time from when it is produced, giving them more flexibility and allowing them to maximize the value of their production. Net metering is specifically allowable for small-scale cogeneration of electric in approximately 10 states.

In states without net-metering policies, a second meter is usually installed to measure the electricity that flows back to the provider, with the provider purchasing the power at a rate much lower than the retail rate.

The MCHP interface uses solid-state power electronics, taking the raw power it generates and matching it to place it in phase with the grid. And it provides all of the protection needed to use the grid, for example, if the grid loses power, MCHP immediately disconnects. Climate Energy is also working with electric utilities for the creation of additional, and more coherent grid standards, Guyer says.

By employing a method that delivers a low flow rate of heated air to the building, the system reduces temperature swings and the cycling normally experienced with home heating appliances, increasing thermal comfort. Its constant operation also draws more air through the filtration system, increasing indoor air quality. And the system generates power with less noise, at 44 dB(A) at 3 feet, equivalent to the sound level of a museum. The Honda MCHP is designed to last more than 20,000 hours before requiring any major maintenance, and it is connected to the Internet for remote monitoring control, troubleshooting, diagnostics and service messages.

The Micro-CHP System can also provide homeowners with full-house automatic standby power in the event of a power outage with the addition of a standby generator (10 kW to 25 kW). The generator will be located outside the home, and operated by the MCHP System controller, which equips the homeowner with service support.

The Honda MCHP technology, used by Climate Energy in their system, has been installed in some 15,000 Japanese homes, in system configurations developed by Japanese natural gas companies for the Japan market. Senertech, Schweinfurt, Germany, another producer of small-scale cogeneration systems has installed about 10,000 units in Europe. Nevertheless, Guyer notes that these systems are still somewhat oversized and overpriced for the residential market.

A joint venture by ECR International, Utica, N.Y. and Yankee Scientific, Medfield, Mass., Climate Energy, also based in Medfield, was created five years ago with the specific purpose of exploring micro-CHP technology. After meeting with a global mix of engine manufacturers, Climate chose American Honda Motor Company, Torrance, Calif., Guyer says, because its small combustion engine, “answered all of our questions.”

Prior to Climate Energy’s partnership with Honda, no manufacturer of U.S. heating appliances has been able to deliver a small-scale, heat-and-power device for the home, running on 1 kW, which operated reliably, and with low noise and low maintenance.

“Probably for the last 50 years, you have seen electric power generation in the home talked about in Popular Science. All of those things were more or less technical curiosities, and so this technology is the only one that is right across the board,” Guyer says. “This is very much like the hybrid automobile in that the hybrid automobile represents real good engineering applications of many of the technologies we already have on hand.”

The Climate Energy Micro-CHP System will be introduced in Massachusetts this year with the sale of 25 units, and is expected to be produced for the general market in 2006 at a cost under $10,000. The company is designing a system that can run on propane. Climate Energy is additionally working on hydronic Micro-CHP systems for homes that have boilers for heating with baseboard, radiant and other types of hydronic (hot water) heating systems. Climate Energy will use existing pipes for heat distribution throughout the building, and the hydronic version will also easily provide domestic water heating using conventional indirect water heaters. All Climate Energy Micro-CHP System works with conventional air conditioning in the same manner as traditional heating systems. Along with the Honda M-CHP unit, the hydronic version of their system will feature a state-of-the-art ECR International cast aluminum condensing boiler.