Smart Grid, Passive and Active Solar, Electric Vehicles, V2G, Energy Efficiency, Microgrid and More in One Place

4 Apr 2014

On March 25th at the University of California Davis campus an iPad was touched and the Honda Smart Home (HSH) was officially open. This state-of-the-art dwelling is a collaborative effort between American Honda Motor Company and UC Davis. Located on the newly constructed West Village part of the campus, the project brings to real life and integrates many of the concepts and technologies that readers of COG have probably had some role in developing and advancing. West Village is the largest planned zero net energy housing development in the United states, and also houses the university's internationally recognized research centers focused on energy efficiency, sustainability and transportation.

An overview of the HSH sustainability features starts with its energy efficient building features, which reduce load to about half of what would be expected in normal construction. The home’s energy systems meet the reduced load with roughly double the usual efficiency. Its photovoltaic array produces enough energy to power the home as well as an electric vehicle, with a small surplus. Radiant heating and cooling are installed in the floors and ceiling, and are heated and cooled by a geothermal heat pump system. Heat is recovered from the waste water, which is then used in the geothermal system and the xeriscaped yard.

Honda home energy management system

The HSH uses Honda’s home energy management system, or HEMS, a proprietary hardware and software system that monitors, controls and optimizes electrical generation and consumption throughout the home’s microgrid.

A 10 kWh battery energy storage system in the garage, using the same lithium-ion cells that are used in the Honda Fit EV, allows stored solar energy to be used at night, when household demand typically peaks and electric vehicles are usually charged. Honda’s HEMS leverages the battery to balance, shift and buffer loads to minimize the home’s impact to the electric grid. The system also enables Honda and UCD researchers to evaluate the second life, or reuse, of EV batteries in grid applications, home-to-grid connectivity and other concepts.

Honda’s HEMS is also capable of improving grid reliability by automatically responding to demand response signals and providing other grid services. If the electricity grid is overloaded, for example, Honda Smart Home is capable of shedding its load and even supplying power back to the grid. This type of smart grid connectivity will enable the mass deployment of electric vehicles and renewable energy without sacrificing grid reliability.

Solar photovoltaics — A 9.5 kW solar photovoltaic system mounted on the roof will generate more energy than the home and Fit EV consume on an annual basis, due in large part to the efficient design of the home. All of the energy for space heating, space cooling, ventilation, lighting, hot water, appliances and consumer loads, in addition to the transportation energy for the Honda Fit EV, is supplied by the solar panels on the home. Honda Smart Home is expected to generate a surplus of 2.6 megawatt-hours of electricity over the course of a year, while a comparable home will consume approximately 13.3 megawatt-hours. This results in a net offset of nearly 13,100 pounds of CO2 per year, even when taking into account California’s relatively clean electricity. The excess energy anticipates potential future increases in energy needs, such as the addition of more occupants or electric vehicles to the home, and an increased daily commute.

Electric vehicle charging — The Honda Fit EV included with the home has been modified to accept DC power directly from the home’s solar panels or stationary battery, eliminating up to half of the energy that is typically lost to heat during DC-to-AC and AC-to-DC power conversion. When the solar panels are generating electricity at full capacity, the vehicle can fully recharge in approximately two hours directly from sunlight.

Geothermal radiant heating and cooling — In homes and cars, heating and air conditioning systems consume significant amounts of energy. In the ground beneath the Honda Smart Home’s back yard, eight 20-foot-deep boreholes allow a geothermal heat pump to harness the ground’s relatively stable thermal sink to heat and cool the home’s floors and ceiling throughout the year. Researchers from UC Davis will evaluate the performance of the system to determine its adaptability to mainstream use.

Other sustainability features include sustainably farmed woods for its advanced double-stud framing as well as interior furnishings. Because cement has such a heavy carbon footprint, half the cement in the post-tensioned concrete slab foundation was replaced with pozzolan, a naturally occurring material. Ninety-six percent of the construction waste was recycled.

A myriad of other features make this house healthy and livable. No formaldehyde-emitting materials were used. Low-VOC finishes were used throughout.  The lighting system changes hue from bluish to yellowish morning to evening because research has shown an interaction between light color, melatonin production in humans, and therefore an interaction with our daily circadian rhythms. Automatic sensors open windows for natural ventilation.

The California Energy Efficiency Strategic Plan sets a goal for all new residential buildings to be zero net energy by 2020. Honda Smart Home surpasses that goal by producing enough energy to power the home and an electric vehicle on a daily basis.

Welcome to the future.


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