Method of improving air cooled packaged units performance for multi-packaged-units installations
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Solution Overview
Problem
HVACR systems with arrays of packaged units face efficiency issues due to upstream units heating the ambient fluid, which reduces the efficiency of downstream units by causing them to operate outside their optimal temperature range, leading to increased energy consumption.
Innovation Solution
A controller adjusts the operation of packaged units by turning off or partially shutting down upstream units to lower the ambient fluid temperature received by downstream units, optimizing the array's efficiency by selecting units based on operating patterns and ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If upstream packaged units operate to provide cooling, then cooling capacity is provided to the conditioned space, but the exhaust heat from upstream units heats the ambient fluid, causing downstream units to receive ambient fluid above the optimal temperature range and reducing their efficiency
Solution Approach 1:
The system dynamically adjusts the operation of packaged units based on real-time ambient fluid temperature measurements and operating conditions. The controller monitors the temperature of ambient fluid received by each unit and dynamically determines whether to operate, partially operate, or shut down units to maintain optimal operating temperatures, thereby resolving the contradiction between providing cooling capacity and minimizing energy consumption
Solution Approach 2:
The system changes the operational parameters of packaged units (on/off status, load level) based on the temperature parameter of the ambient fluid. By adjusting these parameters dynamically, the system ensures that downstream units receive ambient fluid within the optimal temperature range, preventing efficiency degradation while maintaining required cooling capacity
2Power
If all packaged units in the array operate simultaneously, then maximum cooling capacity is provided, but downstream units receive heated ambient fluid and operate outside their optimal temperature range, reducing overall array efficiency
Solution Approach 1:
The system applies partial action by operating only the necessary number of packaged units based on the actual cooling load and ambient fluid temperature conditions. Rather than operating all units simultaneously, the controller selectively operates units to provide sufficient cooling capacity while preventing downstream units from receiving overheated ambient fluid, thus maintaining optimal operating conditions for all active units
3Productivity
If downstream units operate with heated ambient fluid, then cooling load is met, but the units consume more energy and operate less efficiently
Solution Approach 1:
The system uses feedback from temperature sensors that monitor the ambient fluid temperature received by each packaged unit. This feedback information is fed to the controller, which adjusts the operation of upstream and downstream units accordingly. When downstream units detect elevated ambient fluid temperature, the system responds by adjusting upstream unit operation to reduce heat discharge into the ambient fluid, thereby maintaining downstream unit efficiency while meeting cooling load requirements
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
This approach improves the overall efficiency of the HVACR system by ensuring downstream units operate within their optimal temperature range, reducing energy consumption and enhancing performance.
Implementation Method 1
The rooftop units can include one or more heat exchangers to facilitate thermal energy exchange between a heat transfer fluid and the outdoor air
Implementation Method 2
A fan can move the conditioned indoor air in an air distribution system to condition the entire building
Implementation Method 3
the upstream rooftop units in the group can exhaust heat into the outdoor air, heating up the intake temperature of a downstream rooftop unit in the same group
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes an array of packaged units; and a controller to obtain an operating condition of the array of packaged units, derive the operating condition to construct an operating pattern, select one or more packaged units to be adjusted to increase efficiency of the array of packaged units based on the operating pattern, and to adjust operation of the one or more packaged units selected by the controller.