System and method for submetering of a heating, ventilation, and/or air conditioning (HVAC) system
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Solution Overview
Problem
Existing HVAC systems face challenges in efficiently and cost-effectively metering the power consumption of individual units within a building, as traditional energy meters are expensive and consume unnecessary energy.
Innovation Solution
The implementation of an HVAC system that includes an energy meter, an airflow meter, and a metering system with a processor to determine individualized power consumption based on airflow rate and HVAC unit power consumption, allowing for precise measurement without the need for multiple energy meters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an energy meter is installed on each VAV box to monitor power consumption, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The system segments the power consumption measurement function: instead of placing complete energy meters at each VAV box, the measurement function is divided between a central energy meter on the HVAC unit and airflow meters at each VAV box. The central energy meter measures total power consumption, while airflow meters measure individual unit airflow, and a processor calculates individual power consumption by combining these measurements with airflow ratios.
Solution Approach 2:
The system introduces airflow measurement as an intermediary parameter to bridge the gap between central energy meter data and individual unit power consumption. By measuring airflow at each VAV box and using it as a proxy for power consumption proportion, the system avoids installing expensive energy meters at each location while maintaining measurement accuracy.
2Measurement precision
If an energy meter is installed on each VAV box to monitor power consumption, then measurement precision is improved, but operational cost increases
Solution Approach 1:
The system extracts the power consumption measurement function from individual VAV box energy meters and consolidates it into a single central energy meter on the HVAC unit. This central meter measures the total power consumption of the entire HVAC system, eliminating the need for multiple distributed energy meters and their associated operational costs.
Solution Approach 2:
Instead of using physical energy meters at each location, the system creates a virtual copy of the measurement function by using airflow data as a proxy indicator. The airflow measurement at each VAV box serves as a copy or representation of the power consumption proportion for that unit, allowing indirect measurement without physical energy meters at each location.
3Measurement precision
If multiple energy meters are installed to monitor individual unit power consumption, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system merges the measurement functions of multiple distributed energy meters into a single centralized energy meter combined with airflow measurements. By combining the central power consumption measurement with individual airflow measurements and using processor-based calculation, the system achieves individual unit measurement capability with a simplified single-point measurement structure.
Solution Approach 2:
The system changes the measurement parameter from direct electrical power measurement at each VAV box to a combination of central power measurement and airflow measurement. By using airflow rate as a correlating parameter that reflects power consumption proportion, the system transforms the measurement approach from electrical domain to fluid dynamics domain, simplifying the overall system architecture.
Data Source
AI summary
In an embodiment of the present disclosure, a method for determining power consumption of a unit of a heating, ventilating, and air conditioning (HVAC) system includes providing conditioned air to the unit from an HVAC unit of the HVAC system. The method also includes receiving power data indicative of a total power consumed by the HVAC unit, receiving airflow data indicative of a rate of the conditioned air received by the unit from the HVAC unit, determining a power consumption of the unit based on the power data and the airflow data, and outputting the power consumption of the unit.