Air Handling Unit Heat Source Control for Defrost Compensation
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Solution Overview
Problem
The existing controller for heat source equipment in air handling units often prioritizes component protection and defrosting operations over achieving the desired temperature set by the direct digital controller, leading to uncomfortable conditions in the space being air-conditioned.
Innovation Solution
A controller is introduced between the direct digital controller and the heat source equipment, which compares the actual operation with the instructed operation and notifies the direct digital controller of any discrepancies, allowing for real-time adjustments to ensure the heat source equipment operates within specified capabilities, thereby maintaining comfortable conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heat source equipment prioritizes component protection and defrosting operations, then the reliability of the heat source equipment is improved, but the temperature control accuracy deteriorates
Solution Approach 1:
The controller continuously monitors the actual operation content of the heat source equipment and compares it with the instructed operation content. When a discrepancy is detected (such as defrosting or protection operations occurring when they shouldn't), the controller notifies the DDC and adjusts control parameters to compensate, ensuring temperature accuracy is maintained despite intermediate operations
Solution Approach 2:
The controller acts as an intermediary device between the DDC and the heat source equipment. It receives instructions from the DDC, monitors actual equipment responses, and makes real-time adjustments to reconcile discrepancies caused by protection operations, thereby maintaining overall system temperature control accuracy
2Reliability
If the heat source equipment performs defrosting operation preferentially, then the reliability of the heat source equipment is improved, but the temperature control accuracy deteriorates
Solution Approach 1:
The controller monitors whether defrosting operations are occurring when they shouldn't be (based on instructed operation content). When unauthorized defrosting is detected, the controller compensates by adjusting control parameters and notifying the DDC, ensuring temperature accuracy is restored despite the defrosting interruption
Solution Approach 2:
The controller proactively monitors the operation status of the heat source equipment before temperature deviations become significant. When it detects that defrosting or protection operations are about to occur or are occurring inappropriately, it takes preliminary compensatory actions to minimize the impact on temperature control accuracy
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 solution ensures that the air-conditioned space maintains the set temperature by compensating for any deviations in the heat source equipment's operation, ensuring consistent and comfortable air conditioning.
Implementation Method 1
a heat exchanger which causes the outside air drawn in by the air blower and a refrigerant fed from the heat source equipment to exchange heat with each other
Data Source
Figure 1
Figure 2~4
AI summary
According to one embodiment, there is provided a controller (50, 60) for heat source equipment (20, 30) connected to an air handling unit (1). The air handling unit (1) includes an air blower (15) which draws in outside air, a heat exchanger (21, 31) which causes the outside air drawn in by the air blower (15) and a refrigerant fed from the heat source equipment (20, 30) to exchange heat with each other. The air handling unit (1) supplies as air for air conditioning, air passing through the heat exchanger (21, 31) to space to be air-conditioned. The controller (50, 60) includes a module which notifies a controller (40) for an air handling unit (1) of operation content different from operation content specified by an instruction given from the controller (40) of the air handling unit (1) if the heat source equipment (20, 30) performs an operation corresponding to the operation content different from the operation content specified by the instruction.