Single-Stage Compressor Cycling Schedule for Demand Response Comfort
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Solution Overview
Problem
HVAC systems struggle to maintain comfort and efficiently reduce energy consumption during peak demand response times, failing to effectively manage single-stage compressor operations.
Innovation Solution
An HVAC system with a controller that determines an operation schedule for the single-stage compressor based on predictive indoor temperature and occupancy models, alternating its on-off cycles to maintain comfort while meeting energy-saving requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the single-stage compressor operates continuously to maintain comfortable indoor temperatures, then occupant comfort is improved, but energy consumption increases during peak demand response times
Solution Approach 1:
The system performs preliminary cooling before the demand response period begins, storing cooling capacity in the building's thermal mass (walls, floors, furniture). This allows the compressor to be curtailed or shut off during peak demand times while maintaining comfortable temperatures through the stored cooling effect.
Solution Approach 2:
The controller implements periodic on-off cycling of the single-stage compressor during the demand response event, alternating between active cooling periods and curtailment periods. This periodic operation reduces average energy consumption while maintaining temperature within acceptable ranges through thermal inertia.
2Use of energy by moving object
If the single-stage compressor is turned off during demand response to reduce energy consumption, then energy saving requirements are met, but indoor temperature comfort deteriorates
Solution Approach 1:
The system proactively pre-cools the building envelope and thermal mass before the demand response curtailment begins, creating a thermal buffer that maintains comfortable temperatures during the off-period without requiring active compressor operation.
Solution Approach 2:
The controller calculates and prepares sufficient cooling capacity in advance to cushion against temperature rise during curtailment. This involves determining the appropriate pre-cooling duration and intensity based on forecasted outdoor temperatures, building thermal characteristics, and the expected curtailment schedule.
3Adaptability or versatility
If the HVAC system reduces compressor operation to meet demand response limits, then compliance with energy restrictions is improved, but system productivity in providing cooling service decreases
Solution Approach 1:
The system maximizes cooling service productivity before the demand response event by pre-cooling the building to the lowest comfortable temperature setpoint. This stored cooling capacity then substitutes for active compressor operation during curtailment, maintaining service levels without continuous energy input.
Solution Approach 2:
The building's thermal mass acts as an intermediary energy storage medium, decoupling the timing of cooling service provision from energy consumption. Cooling service is provided during off-peak hours when energy is available, and the thermal mass mediates to deliver this service during peak demand periods when the compressor is curtailed.
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 maintains comfortable indoor temperatures while reducing energy consumption by intelligently managing compressor operation, ensuring compliance with demand response limits.
Implementation Method 1
a single-stage compressor configured to compress a refrigerant used to cool air provided to the space
Implementation Method 2
Air is cooled via heat transfer with refrigerant flowing through the HVAC system
Data Source
AI summary
An HVAC system is configured to regulate a temperature of a space. The HVAC system includes means for compressing a refrigerant used to cool air provided to the space and a controller communicatively coupled to the means for compressing. The controller determines that a demand response time period is starting at a start time. After determining that the demand response time period is starting at the start time, an operation schedule is determined indicating alternating portions of the demand response period during which the means for compressing is to be turned off and turned on. At or after the start time of the demand response time period, the controller begins operating the means for compressing according to the determined operation schedule.