Staggered HVAC Start-Up Control for Power Spike Reduction
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Solution Overview
Problem
HVAC systems experience power spikes when multiple units start up simultaneously, which can occur during occupancy changes, leading to high power demands and inefficiencies.
Innovation Solution
An HVAC controller that generates an offset delay value for starting components, ensuring staggered start-ups of HVAC units to prevent simultaneous activation and thereby minimize or eliminate power spikes, using a processor to receive delay signals and apply unique delay values to each unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple HVAC units start up simultaneously to meet cooling or heating demand, then the system responds quickly to occupancy changes, but power spikes occur causing high power demands and electrical grid strain
Solution Approach 1:
The system implements a preliminary delay action by introducing an offset delay value before HVAC unit start-up. The controller receives a delay originating signal and automatically generates an offset delay value to delay the start-up of identified components (compressors, blowers, fans). This preliminary delay prevents simultaneous start-up of multiple units, thereby eliminating power spikes while still meeting cooling or heating demands in a staggered manner.
2Power
If HVAC units are manually programmed with default start-up values to prevent power spikes, then power demand is reduced, but the programming process is time consuming and requires coordination between units
Solution Approach 1:
The system enables self-service by allowing each HVAC controller to automatically generate its own offset delay value without manual programming. When a delay originating signal is received, the controller autonomously determines the appropriate delay value and applies it to its identified components. This eliminates the need for time-consuming manual coordination between multiple HVAC units while still achieving power spike prevention.
3Power
If HVAC components are delayed to prevent power spikes, then power demand is reduced, but the delay in starting components may affect the system's ability to meet cooling or heating demands
Solution Approach 1:
The delay action is applied preliminarily and automatically only during start-up conditions when a delay originating signal is received. Once the offset delay value is applied and components start in a staggered manner, the system transitions to normal operation where it can meet cooling or heating demands reliably. The preliminary delay is temporary and does not permanently impede the system's ability to satisfy thermal demands.
Data Source
AI summary
An HVAC controller, a method of starting a HVAC unit and a HVAC system are disclosed herein. In one embodiment, the HVAC controller includes: (1) an interface configured to receive a delay originating signal and (2) a processor configured to automatically generate an offset delay value for the HVAC unit upon receipt of the delay originating signal and delay starting identified components of the HVAC unit based on the offset delay value.