Variable Speed Drive Battery Backup for HVAC&R Grid Interruptions
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Solution Overview
Problem
Existing HVAC&R systems face power interruptions and high operational costs due to fluctuations in grid power supply, which can lead to system shutdowns and increased expenses during peak demand hours.
Innovation Solution
A battery is electrically coupled to the variable speed drive via a DC bus, allowing it to supply auxiliary power during grid interruptions and high-cost periods, with rectifiers and inverters converting AC power to DC and back to AC with variable voltage and frequency, enabling continuous operation and reducing energy costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the HVAC&R system is electrically coupled to the power grid, then it can receive continuous power supply, but it experiences interruptions and inconsistencies in power supply
Solution Approach 1:
The battery is charged in advance during normal operation to store energy before power interruptions occur. This preliminary energy storage enables the system to maintain operation during grid failures without shutdown, resolving the contradiction between reliability and operational stability.
Solution Approach 2:
The battery acts as an intermediary energy storage device between the power grid and the HVAC&R system. It buffers the inconsistencies and interruptions from the grid, providing stable power to the system while maintaining reliability during grid failures.
2Loss of energy
If the battery supplies auxiliary power during peak demand hours, then operational costs are reduced, but the system requires additional energy storage capacity
Solution Approach 1:
The variable speed drive dynamically adjusts motor speed and power consumption based on real-time conditions. This dynamic operation reduces peak power demands, allowing the battery to provide auxiliary power during peak demand hours without requiring excessive battery capacity, thus reducing energy costs while managing storage requirements.
Solution Approach 2:
The system changes operational parameters by adjusting motor speed through the variable speed drive. This parameter adjustment optimizes power consumption patterns, enabling more efficient use of battery stored energy during peak demand periods and reducing overall energy costs.
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 battery ensures continuous operation of HVAC&R systems by providing auxiliary power during grid outages and peak demand hours, reducing shutdowns and operational costs by utilizing stored energy and optimizing power usage.
Implementation Method 1
a battery (100) electrically coupled to the variable speed drive (52) and configured to supply auxiliary power to the variable speed drive (52)
Implementation Method 2
with rectifiers and inverters converting AC power to DC and back to AC
Implementation Method 3
with rectifiers and inverters converting AC power to DC and back to AC with variable voltage and frequency
Data Source
Figure 1
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Figure 3
AI summary
Embodiments of the present disclosure relate to a heating, ventilating, air conditioning, and refrigeration (HVAC&R) system that includes a variable speed drive (VSD) (52) configured to supply power to a motor (50) configured to drive a compressor (32) of the HVAC&R system, a rectifier (102) of the VSD (52) configured to receive alternating current (AC) power from an AC power source (108) and convert the AC power to direct current (DC) power, a DC bus (106) of the VSD (52) electrically coupled to the rectifier (102), an inverter (104) of the VSD (52) electrically coupled to the DC bus (106), where the inverter (104) is configured to convert the DC power to output AC power, the output AC power has a variable voltage and a variable frequency, and the output AC power is directed to the motor (50), and a battery (100) electrically coupled to the DC bus (106), where the battery is configured to provide auxiliary DC power to the VSD (52).