Sharp Begins to Test 'Ultimate Power Saving' House

Jun 10, 2011
Tetsuo Nozawa, Nikkei Electronics

Sharp Corp announced June 8, 2011, that it has completed the "Sharp Eco House" in an industrial district in Sakai City, Osaka Prefecture, Japan, and disclosed it to mass media.

The completed "Sharp Eco House." Polycrystalline PV panels (9kW) were mounted on the roof. The gross floor area of the house is 271.24m2, which is about twice as large as that of a common single-family home in Japan.
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The company will start a field test of its technology to realize "ultimate power saving" by minimizing power consumption and ensuring the comfort of living space within June 2011. It has already started to collect preliminary data.

The Eco House was made by using many power-saving, power-generating and power-storing technologies that are currently available for houses.

They include (1) Sharp's photovoltaic (PV) battery with an output of 9kW, (2) LED lighting equipment that works together with a human presence sensor and an illuminance sensor, (3) a system that visualizes the power consumptions of home electronics, (4) power-saving home electric appliances that can be controlled by using an HEMS (home energy management system) and (5) "DC home appliances," which operate with direct-current (DC) electricity.

Furthermore, Sharp used a storage battery manufactured by Eliiy Power Co Ltd with an output of 8kWh, an electric vehicle (EV) made by Mitsubishi Motors Corp and Sharp's own power conditioner that can be combined with them.

'Net zero power consumption on annual basis'

According to the documents that Japan's Resources and Energy Agency published in 2010, the ratio of electricity consumed at home to the total electricity consumed in Japan is about 29%, which is not low. The Eco House can realize net zero consumption of grid electricity on an annual basis, Sharp said. In other words, it is possible to cover the entire electricity consumption with PV energy.

The "Smart Tap" power supply adapters and the tablet computer for visualization are scheduled to be commercialized within fiscal 2011.
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The breakdown is as follows. About 30% of the power consumption at home can be cut on an annal basis by purchasing the latest power-saving home electric appliances and LED lighting equipment. And the visualization of power consumption, the use of the automatic control function using the HEMS, the combination of the PV energy, storage battery and EV and the use of the DC home appliances cut approximately 15%, 10%, 35% and 10% of the total power consumption, respectively. They add up to 100%.

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The tablet computer visualizes (1) the amount of power generated by the PV battery, (2) the charge/discharge statuses of and the amounts of electricity left in the house's and EV's storage batteries and (3) the power being consumed in the house.
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Among them, the visualization system and the HEMS consist of (1) the "Smart Tap" power supply adapters and its gateway devices and (2) the "Galapagos" tablet computer and LED lighting equipment and home electric appliances that can communicate with the computer via a wireless LAN.

The Smart Tap collects data of the power consumptions of the home electric appliances. Then, the data is transmitted to the tablet computer via a gateway by using the ZigBee wireless sensor standard, visualizing the power consumptions of the home electric appliances.

The screen of the tablet computer, which shows a room layout and a home appliance (air conditioner) controlled by the computer, can be displayed on a TV screen.
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The tablet computer has a function to communicate with the home electric appliances via a wireless LAN and can be used as a remote controller for them. For example, the brightness and color of the LED lamp in the bed room can be adjusted with the computer.

Also, the tablet computer is installed with a program for the HEMS that automatically controls the power consumptions of the lighting equipment and the home electric appliances. Therefore, it functions as a "commander" of the appliances and the EV.

It is possible to change the power consumptions of the home electric appliances by, for example, changing the illuminance of the LED backlight of a TV. And in "the entire house power-saving operation mode," the tablet computer controls the appliances in an entirely automated way while collecting information such as outside air temperature.

1st public field test of V2H

Mitsubishi Motors' 'i-MiEV' electric vehicle can both transmit electricity to the Eco House and receive electricity from the house.
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As for the power-generating and power-storing systems including the PV battery, storage battery and EV, Sharp said, "By using Mitsubishi Motors' 'i-MiEV' electric vehicle, we realized the use of the charge/discharge function of an EV (for a house) for the first time in the industry."

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In other words, the Eco House has not only a function to charge the EV's storage battery with the electricity of the PV battery and the house's storage battery but also a function to use the electricity of the EV's storage battery to charge the house's storage battery and power the home appliances (V2H (vehicle-to-home) function).

The "charge/discharge plug"
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"The charge/discharge output of the EV is up to 8kW," Sharp said. "When fully charged, the EV battery can continuously discharge for two hours."

It is possible to switch between charging and discharging the EV's battery with touch operation of the tablet computer. Furthermore, the power conditioner has a function to automatically disconnect the house from the power grid in the case of power outage, etc and discharge the house's and EV's storage batteries to supply electricity to the home appliances. In the house, there are dedicated power plugs to transmit electricity from the storage batteries.

DC-powered 'Eco Cute' water heater

The newly-developed power conditioner (the largest box seen in the center) and Eliiy Power's storage battery (left to the power conditioner)
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Sharp tests DC home appliances, which operate with DC electricity, by not converting DC electricity from the PV battery and the storage batteries into alternate-current (AC) electricity. With DC-powered air conditioner, TV, LED lighting equipment, refrigerator, "Eco Cute" water heater, etc, the company compares the power consumptions of those DC-powered appliances with those of traditional appliances.

The voltage of the DC electricity supplied to the DC home appliances is 300V. In practice, this electricity goes through DC-DC conversion inside each appliance.

"We believe that some of those home appliances will operate without DC-DC conversion in the future," Sharp said.

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Entire house operates like robot

Sensors are embedded in each room.
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Furthermore, cameras, illuminance sensors and human presence sensors are embedded in each room and corridor of the Eco House. Lamps turn on/off in accordance with the presence of people, and a TV program watched by a person in one room will be automatically displayed on the screen of a TV in another room when the person moves from the first room to the second room.

"If I compare the house to a human, the HEMS is the brain," said Shigemitsu Mizushima, Sharp's executive managing officer. "The communication function, cameras and sensors are nerves. The power conditioner is the heart. The electric wires are blood vessels, and electricity is blood that flows through the vessels."

He also said, "A house maker told us that they have never seen an eco house with such a high perfection level," stressing that the Sharp Eco House is different from other manufacturers' power-saving houses.

Among those systems, Sharp plans to commercialize the visualization system consisting of the Smart Tap and the tablet computer within fiscal 2011. And it intends to commercialize the HEMS having the control function, the home electric appliances compatible with the HEMS and the storage batteries in or after fiscal 2012.

"Many of the communication lines used in the house are wireless," the company said. "So, it is easy to deal with already built houses and to gradually replace appliances."

On the other hand, it might take several to ten years to offer total solutions including the DC home appliances and all the systems, Sharp said.

"Total solutions are for newly-built houses, and the safety of DC home appliances has to be recognized in the society," it said.