Smart Thermostat Preheating for Cold-Weather Demand Response

Solution Overview

Problem

During demand response events, existing HVAC systems face challenges in efficiently managing energy consumption to reduce peak demand on the electrical grid, particularly in cold weather months when heating is required, leading to potential discomfort and increased energy usage.

Innovation Solution

A smart thermostat system that preheats homes before demand response events, adjusts setpoint temperatures, and optimizes the use of heat pump and auxiliary heating stages to minimize energy consumption while maintaining user comfort, by using a thermal model and user settings to determine preheating needs and applying penalties to reduce auxiliary heat usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the HVAC system operates at full capacity during demand response events to maintain user comfort, then user comfort is preserved, but electrical energy consumption increases and grid demand is not reduced

Engineering Contradiction:

Improveuser comfortVSAvoidelectrical energy consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary heating before the demand response event begins by detecting the upcoming event and activating the heating system in advance. This preheating action stores thermal energy in the building structure (walls, floors, furniture), allowing the HVAC system to be reduced or shut off during the demand response event while maintaining user comfort through the stored heat.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If the HVAC system reduces operation during demand response events to lower energy consumption, then electrical energy consumption is reduced, but user comfort deteriorates due to temperature drops

Engineering Contradiction:

Improveelectrical energy consumptionVSAvoiduser comfort

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The system performs preliminary heating before the demand response event begins by detecting the upcoming event and activating the heating system in advance. This preheating action stores thermal energy in the building structure (walls, floors, furniture), allowing the HVAC system to be reduced or shut off during the demand response event while maintaining user comfort through the stored heat.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If auxiliary heating is used extensively to maintain temperature during demand response events, then user comfort is maintained, but energy costs increase due to inefficient heating

Engineering Contradiction:

Improveuser comfortVSAvoidenergy efficiency

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The system performs preliminary heating before the demand response event begins by detecting the upcoming event and activating the heating system in advance. This preheating action stores thermal energy in the building structure (walls, floors, furniture), allowing the HVAC system to be reduced or shut off during the demand response event while maintaining user comfort through the stored heat.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces the need for continuous auxiliary heating operation with a thermal energy storage approach. Instead of relying on inefficient auxiliary heating elements to maintain temperature throughout the demand response event, the system uses the building's thermal mass to store heat and release it gradually, substituting mechanical heating with passive thermal release.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively reduces electrical energy usage during demand response intervals by preheating homes before peak demand hours, optimizing heating strategies, and maintaining user comfort, thus alleviating grid strain and lowering energy costs.

Implementation Method 1

the thermostat periodically causes the HVAC system to activate a heating function to heat an enclosure

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS10088192B2Thermostat algorithms and architecture for efficient operation at low temperatures

Publication Date: 2018.10.02 GOOGLE LLC

AI summary

A thermostat may be programmed to operate during cold-weather months by operating in a heat mode where the thermostat periodically causes the HVAC system to activate a heating function to heat an enclosure based at least in part on the stored setpoint schedule; receiving an indication from a thermostat management server of a demand response event while the thermostat is operating in the heat mode; determining whether the thermostat stores a user setting indicating that the thermostat should preheat the enclosure prior to reaching a scheduled setpoint in the stored setpoint schedule; and preheating the enclosure prior to the demand response event based on a determination that the thermostat stores the user setting indicating that the thermostat should preheat the enclosure prior to reaching the scheduled setpoint in the stored setpoint schedule.