HVAC Compressor Run-Time Extension for Short-Cycle Efficiency
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Solution Overview
Problem
Oversized heating, ventilating, and air-conditioning (HVAC) systems experience short run times, leading to inefficiencies in energy usage, humidity control, and reduced air circulation, resulting in higher operational costs and shorter unit lifespan, despite existing technologies failing to effectively address these issues.
Innovation Solution
A run time extension device that monitors call-for-cool control signals and determines if the requested compressor run time is less than a predetermined minimum, extending the power supply to the compressor and circulation fan to maintain operation beyond the initial request, thereby increasing the total run time and improving energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If oversized AC units are installed to quickly meet cooling demand, then cooling effectiveness is improved, but energy consumption increases due to short run times
Solution Approach 1:
The system performs preliminary action by extending the compressor run time beyond what is immediately needed to meet the cooling load. The controller monitors run time and deliberately keeps the compressor running longer than the minimum required to achieve the desired temperature, thereby pre-conditioning the system for more efficient operation in subsequent cycles.
Solution Approach 2:
The invention applies continuity of useful action by reducing off-time between cooling cycles. Instead of allowing the compressor to shut off completely after meeting the cooling demand, the system maintains continuous operation by extending run time and reducing off-time, ensuring the compressor operates continuously at efficient levels rather than cycling on and off frequently.
2Speed
If oversized AC units are used to quickly cool spaces, then cooling speed is improved, but humidity control deteriorates due to short run times
Solution Approach 1:
The system applies preliminary action by extending the compressor run time beyond what is immediately needed to meet the cooling load. The controller monitors run time and deliberately keeps the compressor running longer than the minimum required to achieve the desired temperature, thereby pre-conditioning the system for more efficient operation in subsequent cycles.
Solution Approach 2:
The invention applies continuity of useful action by reducing off-time between cooling cycles. Instead of allowing the compressor to shut off completely after meeting the cooling demand, the system maintains continuous operation by extending run time and reducing off-time, ensuring the compressor operates continuously at efficient levels rather than cycling on and off frequently.
3Productivity
If demand-response schemes are used to reduce peak loads, then peak demand is reduced, but actual energy usage is not decreased due to time-delayed demand
Solution Approach 1:
The invention applies continuity of useful action by reducing off-time between cooling cycles. Instead of allowing the compressor to shut off completely after meeting the cooling demand, the system maintains continuous operation by extending run time and reducing off-time, ensuring the compressor operates continuously at efficient levels rather than cycling on and off frequently.
Data Source
AI summary
An extended run time device for extending the time that a compressor-based heating, ventilating, and air-conditioning (HVAC) system runs so as to increase energy efficiency of the HVAC system. The extended run time device includes a sensing circuit, a switching device and a processor. Based upon a signal from the sensing circuit, the processor causes the switching device to transmit a proxy control signal to the compressor, thereby causing power to the compressor to be maintained for a time period longer than a time period requested by the temperature control device.