Two-Stage Thermostat Control for Modulating Air Conditioners
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Solution Overview
Problem
Single-stage air conditioning systems cause discomfort and increased energy bills due to sudden temperature changes, while two-stage and modulating furnaces are costly and require new thermostats for optimal operation.
Innovation Solution
A method and system that enables a two-stage thermostat to control a modulating air conditioning system by issuing call signals for first and second-stage operations, allowing the system to operate at specific power levels based on demand, thereby integrating with existing two-stage thermostats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a modulating air conditioning system is used to reduce sudden air flow and improve comfort, then occupants' comfort is improved, but the cost of the thermostat and system installation increases
Solution Approach 1:
The two-stage thermostat is designed to perform multiple functions: it can control both traditional two-stage systems and modulating systems. The thermostat includes a modulating interface that enables it to communicate with modulating air conditioning systems, allowing a single device to serve multiple control needs without requiring separate specialized thermostats for each system type.
Solution Approach 2:
The thermostat dynamically adjusts its control parameters based on the type of air conditioning system it is controlling. When connected to a modulating system, the thermostat modifies its output signals to accommodate modulating operation, thereby enabling cost-effective control of modulating systems without requiring a completely different thermostat design.
2Measurement precision
If a two-stage furnace control approach is used to increase temperature control precision, then occupants' comfort is improved, but sudden air flow gusts still occur during periodic on-off operation
Solution Approach 1:
The system transitions from static two-stage control to dynamic modulating control, where the air conditioning system can continuously adjust its output capacity. The modulating interface enables the thermostat to control the system across a range of capacities rather than fixed stages, allowing smooth transitions and eliminating sudden air flow gusts while maintaining precise temperature control.
3Ease of operation
If a modulating furnace operates in small incremental stages to reduce sudden air flow, then occupants' comfort is improved, but the thermostat cost significantly increases
Solution Approach 1:
The two-stage thermostat incorporates a modulating interface that enables it to control modulating air conditioning systems, allowing a single thermostat design to serve both traditional two-stage and modulating systems. This universal capability eliminates the need for expensive specialized modulating-only thermostats while still providing smooth air flow control through modulating operation.
Data Source
AI summary
A method for effecting cooperation between a modulating air conditioning system and a two-stage thermostat for satisfying an air conditioning load demand in a conditioned space includes: (a) operating the thermostat in a plurality of succeeding operating cycles to issue a first call signal or a second call signal indicating a first or second stage operation by the air conditioning system; the first and second stage operation being effected according to a first operating regimen to satisfy the air conditioning load demand; (b) operating the air conditioning system in response to the first and second call signals; the air conditioning system operating at a first power level when receiving the first call signal and operating at a predetermined second power level when receiving the second call signal; the first power level being established by the air conditioning system according a second operating regimen.