DENSO Develops Home Energy Management System

Dec. 7, 2011

- With optional storage battery to better manage power consumption -

Kariya (Japan) - DENSO Corporation has jointly developed a home energy management system (HEMS) with TOYOTA Housing Corporation and Misawa Homes Co., Ltd. The HEMS, DENSO's first such product of its kind, has optional functions that work with plug-in hybrid or electric vehicles. It will be available in the Japanese market in or after February 2012.

"As plug-in hybrid and electric vehicles become more widespread, we recognized that it's possible to realize a more environmentally friendly society by connecting and coordinating these types of vehicles and home energy usage," said Koji Kobayashi, executive vice president of DENSO Corporation. "DENSO will not only contribute to the development of environmentally friendly vehicles, but also to the development of products that help improve home energy efficiency."

How HEMS Works:
DENSO's HEMS consists of a control unit and a 7-inch touch panel monitor, installed inside the house. The monitor shows real-time power consumption, helping to remind users to turn off appliances when they are not in use, which also helps them better manage electricity. The monitor can also show electricity consumption in terms of cost and the amount of CO2 emissions that are emitted, as well as historical data, which helps encourage users to be more aware of saving energy. Additionally, the system prevents the circuit breaker from tripping when there is a high electric load.

HEMS Connects to Smartphone:
When the HEMS is connected to an external information center it allows the user to remotely check and switch on and off some home appliances from their Smartphone. For example, users could switch on climate control systems*1, check whether the electrically controlled front door is properly locked, and fill the bathtub with hot water*2 using their Smartphone.

Consumers also can use HEMS to schedule a time*3 to charge a plug-in hybrid or electric vehicle battery by coordinating with vehicle battery chargers. That means consumers can schedule battery charging for nighttime, when electricity rates are lower. After signing a contract with a car maker and connecting with the information center, users can remotely turn on the vehicle's climate control system*4 using the HEMS monitor or Smartphone.

Optional Household Battery:
DENSO has also jointly developed a household storage battery system with TOYOTA Housing Corporation, Misawa Homes Co., and Shin-Kobe Electric Machinery Co., Ltd. When used with the HEMS, the battery, with a capacity of 8.4 kWh*5, can better control power consumption at home during peak demand hours. The battery system can power a minimum number of appliances, such as room lighting, for a certain period of time*6 in case of a power outrage.

These products utilize the results from the Japan's Ministry of Economy, Trade and Industry's "Next-Generation Energy and Social Systems Demonstration" (5 year plan from 2010). DENSO will continue to improve these products with input from this project.

DENSO Corporation, headquartered in Kariya, Aichi prefecture, Japan, is a leading global automotive supplier of advanced technology, systems and components in the areas of thermal, powertrain control, electric, electronics and information and safety. Its customers include all the world's major carmakers. Worldwide, the company has more than 200 subsidiaries and affiliates in 35 countries and regions (including Japan) and employs approximately 120,000 people. Consolidated global sales for the fiscal year ending March 31, 2011, totaled US$37.7 billion. Last fiscal year, DENSO spent 9.3 percent of its global consolidated sales on research and development. DENSO common stock is traded on the Tokyo and Nagoya stock exchanges. For more information, go to

The profiles of the HEMS and household storage battery system are as follows.

Profile of HEMS

  • User-friendly 7-inch touch panel TFT LCD monitor
  • Industry's first (as of November 2011) system to integrate remote controller for household water heating system, display of electricity power sold and bought from photovoltaic generation, and charging status of a plug-in hybrid or electric vehicle battery and the household storage battery system
  • Displaying the real-time amount of power consumption and the historical data of ten years (Can also display amount used for water and gas with optional measuring device*7)
  • Scheduling time to charge the battery and remotely turning on the vehicle's climate control system through coordination with battery charger and information center
  • Scheduling charging time of household storage battery

Profile of household storage battery system

  • Input (rated voltage): 200 VAC
  • Output (rated voltage): Normal operation: 100/200 VAC; Power outage operation: 100 VAC
  • Output (rated capacity): Normal operation: 1.5 kW; Power outrage operation: 1.0 kW
  • Battery capacity: 8.4 kWh (storage capacity of 5 kWh when in use)
  • Dimensions: 1,500 x 345 x 1,430 mm (Width x Depth x Length)
  • Weight: Approx. 520 kg
  • Working with the electricity supply system

*1 Only the systems designed for home automation can conduct power-on and -off operations.
*2 Only works with DENSO's CO2 Heat Pump Water Heater
*3 Only works with designated battery chargers
*4 Only works with some of vehicles installing information communication function (functions differ with vehicle model)
*5 Storage capacity of 5 kWh when in use
*6 Approximately 10 hours for using three 150W appliances such as incandescent lightbulb, liquid crystal television and notebook computer. Will differ with the electricity consumption and condition of use of appliances.
*7 Only works with designated sensors

Conceptual Image of HEMS

HEMS's Touch Panel

Household Storage Battery System