Face-Split Evaporator HVAC Design for Peak Demand Power Reduction
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Solution Overview
Problem
HVAC systems face challenges in maintaining comfortable temperatures during peak demand response times while reducing power consumption, as existing technologies lack effective tools to increase sensible capacity and maintain comfort under restricted operating conditions.
Innovation Solution
The implementation of a variable-speed compressor and blower system, along with a face-split evaporator, allows for adjustable airflow and refrigerant compression to increase the sensible heat ratio, enhancing cooling capacity and comfort by temporarily modifying operating parameters during peak demand response times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the HVAC system operates at high power consumption to maintain comfortable temperatures, then cooling capacity is improved, but power consumption increases during peak demand response times
Solution Approach 1:
The system dynamically adjusts the sensible heat ratio by controlling the ratio of airflow rate to cooling capacity. During peak demand response times, the controller modifies operating parameters to increase the sensible heat ratio, allowing the system to maintain comfortable temperatures with reduced power consumption by optimizing the dynamic relationship between airflow and cooling output.
Solution Approach 2:
The system changes the sensible heat ratio parameter by adjusting the ratio of airflow rate to cooling capacity. By modifying this parameter during peak demand response times, the system can provide adequate cooling while consuming less power, as the increased sensible heat ratio allows for more efficient heat transfer at lower power levels.
2Use of energy by moving object
If the HVAC system reduces power consumption during peak demand response times, then power consumption is decreased, but cooling capacity and comfort are compromised
Solution Approach 1:
The system dynamically adjusts the sensible heat ratio to optimize performance during peak demand response times. By controlling the ratio of airflow rate to cooling capacity, the system can reduce power consumption while maintaining adequate cooling capacity and comfort levels through optimized dynamic operation rather than static reduction.
Solution Approach 2:
The system changes the sensible heat ratio parameter during peak demand response times to improve cooling efficiency. This parameter change allows the system to achieve lower power consumption while maintaining or improving cooling capacity, as the optimized sensible heat ratio enables more effective heat transfer at reduced power levels.
3Adaptability or versatility
If the HVAC system operates with fixed operating parameters, then system simplicity is maintained, but ability to increase sensible capacity during peak demand response times is limited
Solution Approach 1:
The controller is designed to perform multiple functions: normal cooling operation and peak demand response mode with increased sensible heat ratio. This multi-functionality allows the system to adapt to different operating conditions without requiring separate dedicated systems, achieving adaptability while managing complexity through a single integrated control unit.
Solution Approach 2:
The system uses parameter changes in the sensible heat ratio as a flexible mechanism to adapt to different operating conditions. By modifying this parameter during peak demand response times, the system achieves enhanced sensible capacity without major structural changes, balancing adaptability with manageable system complexity.
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 effectively increases the sensible capacity of HVAC systems, providing more comfortable temperatures during peak demand response times while satisfying power reduction requirements, offering improved performance and cooling efficiency compared to previous technologies.
Implementation Method 1
a variable-speed compressor configured to compress refrigerant flowing through the HVAC system
Implementation Method 2
The top evaporator circuit is configured to transfer heat from a first portion of a flow of air passing across the top evaporator circuit to refrigerant in the top evaporator circuit. The bottom evaporator circuit is configured to transfer heat from a second portion of the flow of air passing across the bottom evaporator circuit to refrigerant in the bottom evaporator circuit.
Implementation Method 3
A first portion of the liquid condensate formed on a surface of the top evaporator circuit is allowed to fall on a surface of the bottom evaporator circuit such that the second portion of the flow of air is evaporatively cooled by the first portion of the liquid condensate.
Data Source
AI summary
An HVAC system includes a face-split evaporator. The face-split evaporator includes a top evaporator circuit positioned above a bottom evaporator circuit. The system includes a first compressor associated with the top evaporator circuit, a second compressor associated with the bottom evaporator circuit, and a controller communicatively coupled to the first and second compressors. The controller receives a demand request, which includes a command to reduce power consumption by the HVAC system by a predefined percentage. In response to receiving the demand request, the second compressor is turned off thereby decreasing power consumption by at least the predefined percentage. A portion of a liquid condensate formed on a surface of the top evaporator circuit is allowed to fall on a surface of the bottom evaporator circuit such that a portion of a flow of air passing across the bottom evaporator is evaporatively cooled by the portion of the liquid condensate.