Earlier this week, ACE IoT Solutions made publicly available the source code for an Open HEMS Mobile App. While the Open HEMS Mobile App is available for free download on both the App Store and Google Play Store, publicly releasing the code will enable utilities to assess the Mobile App’s source code and evaluate whether the Open HEMS functionality could help advance energy efficiency and grid resiliency in their service areas. For power providers that opt to deploy Open HEMS, the publicly available code allows them to add the Open HEMS functionality into their existing mobile app.

Open HEMS: Energy Efficiency, Resident Comfort and Grid Interactivity

Developed by researchers at Oak Ridge National Laboratory (ORNL), the Open Home Energy Management System (“Open HEMS”) is software that delivers energy efficiency while maintaining resident comfort. The Open HEMS controls the operation of HVAC equipment, hot water heaters, solar panels, Electric Vehicle (EV) chargers and in-home batteries. Open HEMS uses weather forecast data and algorithms tuned to the equipment in a resident’s home to optimize energy usage while also maintaining resident comfort in accordance with a resident’s preferences.

The Open HEMS technology can also control the operation of HVAC equipment, EV chargers, etc in response to signals Open HEMS receives from a power provider. In this manner, Open HEMS can help limit demand for electricity during a peak demand event – utilizing strategies like pre-cooling or staged EV charging. This grid-interactivity enables power providers to manage the load on their grid with more flexibility. ORNL and the Electric Power Research Institute (EPRI) has validated that using Open HEMS enhances the resiliency of the grid via demonstrations with utilities including TVA, EPB, Duke Energy and Southern Company.

TVA developed an animated video – access the video here – that illustrates very well how power providers might use Open HEMS as a tool to enhance the flexibility, security and resiliency of their power grid.

Open HEMS Mobile App: Providing Information and Control to Residents

For utilities, there is a lot to like about the Open HEMS technology. Managing grid resilience is an increasingly critical challenge facing utilities and grid-interactive Home Energy Management Systems can be a useful tool. For some residents, however, technologies like Open HEMS can sound too good to be true or raise concerns about cold showers and uncomfortably warm or cold evenings at home.

The Open HEMS Mobile App provides residents with a single source of information (no need to toggle across multiple apps to access data about different smart home equipment) about their thermostat settings and the status of their connected water heater, solar panels, EV charger and/or battery. The Open HEMS Mobile App also enables residents to, in effect, turn-off the technology that is optimizing the operation of their connected devices. With a single click, a resident can “opt out” of grid-interactive strategies such as pre-cooling or staged EV charging and manually control the operation of devices in their homes.

Open HEMS Mobile App: Designed for Easy Integration While working with Carbon Five to design the Open HEMS Mobile App, TVA reached out to representatives of the 154 Local Power Companies (LPCs) it serves and asked for feedback on the mobile app. Feedback from the LPCs was clear: the Open HEMS mobile app should be designed so that it can be incorporated into an LPC’s existing mobile app. This feedback guided Carbon Five’s design process from the beginning and, as a result, the Open HEMS Mobile App includes the following design elements that will facilitate integration.

  1. The source code is open source. What you see is what you get. No surprises.

  2. The Open HEMS Mobile App is designed to easily incorporate logos and preferred colors.

  3. The Mobile App is modular allowing easy extensibility. Current build out of devices include Thermostat, Water Heater, Solar Panels, EV Charger and In-home battery. Additional devices (smart lights, eg) are easily added.

  4. The Open HEMS Mobile App is configurable, allowing the specific use case for a utility to drive the functionality of the app without recompiling or requiring expensive custom development.

  5. The backend interface for the Open HEMS Mobile App is modular and well documented. As a result, existing apps implement the features for managing an Open HEMS deployment easily.

Access the Open HEMS Repo here.

What is next?

The promise of the Open HEMS technology is a more resilient power grid and reduced costs to ratepayers—all while maintaining resident comfort. At ACE IoT, we hope that utilities, especially those exploring approaches and tools that will allow them to manage the load on their grid, will download the Open HEMS Mobile App, evaluate the code base, and consider pilot deployments to test the Open HEMS technology. The technology to enable grid-interactive smart homes is available and it is Open Source Software.

ACE IoT is pleased to share our experience deploying Open HEMS and managing pilot deployments. Contact Bill Maguire (bill@aceiotsolutions.com) to set-up a call.

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