Predictive Refrigerator Control for Power Loss Mitigation
Design and implementation of a smart appliance controller that uses real-time local weather data (via GPS, NWS, and Network Services) to predict power loss events and preemptively adjust operating parameters to preserve stored goods.
Project Overview
The Challenge: Protecting Perishables from Unpredictable Outages
Electricity interruptions, often caused by severe weather like high winds or storms, lead to rising temperatures inside refrigerators, potentially causing perishable food items to spoil. Traditional appliances rely only on passive insulation to slow this process after an outage occurs.
The challenge was to engineer an intelligent system capable of acting preemptively, using external data sources to predict power loss events and maximize the thermal reserve of the appliance before the grid fails.
The Bespoke Automata Solution: Integrated Location-Aware Control
This project centered on creating a robust, connected controller that integrates multiple external data streams to transition the appliance into a protective 'Power Loss Operating Profile.'
Methodology
Geospatial & Environmental Integration
The core system architecture involves three key steps to establish risk:
- Location Determination: Establishing the precise location of the appliance using methods such as Onboard GPS, Querying WiFi location databases, or localization of assigned public IP Address
- Weather Information Retrieval: Obtaining real-time, localized severe weather information or brownout/blackout notices from sources such as NWS Radio or Internet Information Services
- Risk Assessment: A central Controller evaluates the weather data (e.g., wind speed probability, storm type) and assigns a risk score. If the risk score exceeds a threshold, a "Predicted Power Loss Event" is scheduled.
The Power Loss Operating Profile
Prior to or during the scheduled power loss event, the controller adjusts appliance operations to maximize the storage life of internal contents.
- Pre-Cooling: The primary action is to reduce the temperature set point to the minimum acceptable temperature. This actively over-cools the chilled chamber, building a substantial thermal reserve (cold mass) that can slow the temperature rise during the subsequent power outage.
- Defrost Inhibition: All energy-intensive defrost operations (which raise internal temperatures) are disabled.
- Ice Maker Deactivation: The ice maker is turned off to prevent unnecessary ice production that would melt into liquid water, reducing the volume of water produced inside the appliance during the outage.
Post-Event Assessment and User Notification
The intelligence of the system extends beyond the outage itself.
- Safety Monitoring: The controller continuously logs the temperature of the chilled chamber during the outage duration.
- Food Safety Alert: Upon power restoration, the system analyzes the time spent in the "Food Safety Danger Zone" (e.g., above 40°F) and issues a critical alert to the user, advising them to discard potentially spoiled items.
- User Communication: Users are alerted to the predicted event via display messages, emails, or text messages, often advising them to consume or remove high-risk perishables.