Climate-control system and method of controlling the system
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Solution Overview
Problem
Existing universal holding cabinet (UHC) heating systems consume a large amount of energy, leading to high operational costs and strain on the power grid, despite their necessity in maintaining food products at desired temperatures in restaurants.
Innovation Solution
A climate-control system comprising a heat-pump circuit and a heating-fluid circuit, where the heating-fluid circuit is in a selective heat-transfer relationship with the heat-pump circuit, allowing for energy-efficient operation by switching between modes based on utility provider signals, reducing compressor capacity, and utilizing a fluid storage tank to manage heat transfer effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heat-pump system operates at full capacity to maintain food products at desired temperatures, then heating reliability is improved, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts the compressor capacity between full capacity and partial capacity modes based on thermal energy storage levels in the thermal energy storage unit. This dynamic adjustment allows the system to maintain heating reliability when needed while reducing energy consumption during periods when stored thermal energy can sustain heating operations.
Solution Approach 2:
The system performs preliminary heating action by storing thermal energy in advance in a thermal energy storage unit during full-capacity operation. This stored thermal energy is then utilized during partial-capacity or reduced-operation periods, allowing the system to maintain heating reliability without continuous full-capacity operation, thereby reducing overall energy consumption.
2Use of energy by moving object
If the system operates in reduced capacity mode to save energy, then energy consumption is reduced, but heating capacity decreases
Solution Approach 1:
A thermal energy storage unit acts as an intermediary between the heat pump and the heating load. During reduced-capacity operation, this intermediary releases stored thermal energy to compensate for the reduced heating capacity of the heat pump, thereby maintaining adequate heating output despite operating at lower energy consumption levels.
Solution Approach 2:
The system changes operational parameters by switching between full-capacity and partial-capacity modes based on thermal energy storage levels and heating demands. This parameter change allows flexible adjustment of heating capacity while managing energy consumption, enabling the system to operate efficiently without compromising heating performance when thermal energy is available.
3Use of energy by moving object
If the system switches between full capacity and partial capacity modes, then energy efficiency is improved, but system complexity increases
Solution Approach 1:
The control system uses feedback from thermal energy storage level sensors and heating demand signals to automatically determine when to switch between full-capacity and partial-capacity modes. This feedback mechanism manages the system complexity by providing automated decision-making logic, reducing the need for complex manual control while improving energy efficiency through intelligent mode switching.
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 significantly reduces energy consumption during high-demand periods while maintaining adequate heating capacity, resulting in substantial cost savings for restaurant owners and minimizing the strain on the power grid.
Implementation Method 1
the heating-fluid circuit is in a selective heat-transfer relationship with the heat-pump circuit
Implementation Method 2
an evaporator. The compressor may be configured to circulate a working fluid through the heat-pump circuit
Data Source
AI summary
A system includes a heat-pump circuit and a heating-fluid circuit. The heat-pump circuit includes a compressor and a first condenser conduit. The heating-fluid circuit includes first, second, and third flow-paths. The third flow-path selectively communicates with the first and second flow-paths. The first flow-path includes a first valve. The first valve moves between an open position allowing fluid flow through the first flow-path and a closed position restricting fluid flow through the first flow-path. The second flow-path includes a second condenser conduit and a second valve. When the second valve is open, fluid flows through the second flow-path. In the closed position, the second valve restricts fluid flow through the second flow-path. The third flow-path includes a heat exchanger receiving fluid from the first flow-path when the first valve is in the open position and receiving fluid from the second flow-path when the second valve is in the open position.