Micro Chiller HVAC System for Distributed Zone Temperature Control
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Solution Overview
Problem
Existing HVAC systems for commercial buildings are inefficient due to the need to maintain cold and hot water loops at extreme temperatures to meet peak demands, leading to high energy consumption and carbon emissions, despite these demands being rare.
Innovation Solution
A system utilizing a primary water loop with micro chillers and fan control units that exchange heat with the air, maintaining water temperature between 15-30°C, and using a non-reversible heat engine with a refrigerant loop to efficiently transfer heat within the building, reducing the need for external energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized chiller plants maintain cold water at extremely low temperatures (7°C) to meet peak cooling demand, then cooling capacity is sufficient for maximum load, but energy consumption increases significantly due to rare peak demands
Solution Approach 1:
The invention divides the centralized chiller plant into multiple distributed micro chillers, each serving a specific zone or floor. Each micro chiller operates independently at its own optimal temperature rather than all units maintaining extremely low temperatures simultaneously. This segmentation allows the system to meet peak cooling demands locally without requiring the entire system to operate at maximum capacity, thereby reducing overall energy consumption while maintaining sufficient cooling capacity.
2Reliability
If hot water is maintained at elevated temperatures (50-60°C) to meet peak heating load, then heating capacity is adequate for maximum demand, but system efficiency decreases due to rare peak heating demands
Solution Approach 1:
The centralized hot water plant is segmented into multiple distributed micro chillers with heat recovery capabilities. Each micro chiller can independently provide heating to its served zone at locally optimal temperatures rather than all zones requiring high-temperature water simultaneously. This allows the system to meet peak heating demands in specific zones without maintaining elevated temperatures throughout the entire system, reducing energy losses while preserving adequate heating capacity.
3Adaptability or versatility
If separate hot and cold water loops are used to provide both heating and cooling, then system versatility is improved, but device complexity and energy consumption increase
Solution Approach 1:
Each micro chiller is designed as a universal device capable of providing both cooling and heating functions. The micro chillers incorporate heat recovery systems that capture waste heat from the refrigeration cycle and make it available for heating applications. This multi-functionality eliminates the need for separate dedicated heating and cooling systems, reducing overall system complexity while maintaining the versatility to provide both heating and cooling services.
4Ease of manufacture
If centralized HVAC plants are used to serve entire buildings, then infrastructure requirements are reduced, but energy consumption and carbon emissions increase due to inefficient temperature maintenance
Solution Approach 1:
The system segments the building into multiple zones, each served by its own micro chiller. This allows each zone to be served by appropriately-sized equipment operating at optimal temperatures for local conditions rather than being served by oversized centralized equipment that must maintain extreme temperatures to meet peak demands anywhere in the building. The segmentation approach reduces overall energy consumption while the modular nature of micro chillers keeps infrastructure requirements manageable.
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 system achieves a coefficient of performance (COP) of over 14.0, significantly reducing energy consumption and carbon emissions compared to prior art systems, while maintaining efficient temperature control.
Implementation Method 1
In a first mode a micro chiller transfers heat from the air in the building to the water circulating within the primary water loop
Implementation Method 2
In a second mode the micro chiller transfers heat from the water circulating in the primary water loop to the air in the building
Implementation Method 3
Chiller plant 14 is typically a vapor-compression refrigeration system. The heat engine within the chiller plant chills the water circulating in cold water loop 28 and heats the water circulating within cooling tower circuit 32
Implementation Method 4
The cooling tower can be an open-loop evaporative type or a closed loop type. In either case, heat carried by the water in cooling tower circuit 32 is transferred to air that is pulled through the cooling tower
Data Source
Figure 1
Figure 2
Figure 2B
AI summary
A heating, ventilation, and air conditioning system in which a primary water loop is used as a heat transfer reservoir for both heating and cooling. A plurality of micro chillers are provided, with each micro chiller being connected to the primary water loop. Each micro chiller includes its own heat engine. Each micro chiller includes one or more fan control units that exchange heat between the micro chiller and the air in a building. In a first mode a micro chiller transfers heat from the air in the building to the water circulating within the primary water loop. In a second mode the micro chiller transfers heat from the water circulating in the primary water loop to the air in the building. A primary water loop regulation system is provided to control the temperature of the water circulating in the primaiy water loop.