Heating and cooling system for a food storage cabinet
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Solution Overview
Problem
Conventional methods for maintaining perishable foods at desired temperatures for transport and service are inefficient, as they either rely on bulky and costly refrigeration systems or produce health hazards with flame-based heating sources, and lack portability and rapid temperature control.
Innovation Solution
A thermoelectric system using Peltier chips with manifolds and radiators, along with fans and pumps, allows for efficient heating or cooling within a food transport cart, utilizing a single-type of temperature adjusting element and enabling quick temperature adjustments with a simple control system, and can be integrated with existing food service equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional refrigeration systems are used to chill perishable foods, then cooling capability is provided, but the systems are bulky, costly, require harmful chemicals, and need maintenance
Solution Approach 1:
The patent replaces conventional mechanical refrigeration systems (condensers, coils, chemicals) with a thermoelectric cooling system using Peltier chips that use electrical current to directly create temperature differentials, eliminating the need for complex mechanical components and harmful refrigerants
Solution Approach 2:
The system changes the operating parameters by using solid-state thermoelectric elements that convert electrical energy directly into thermal gradients, allowing cooling without the phase changes and mechanical moving parts of traditional refrigeration
2Temperature
If flame-based heating sources are used to heat food, then heating capability is provided, but local hot spots, uneven heating, and harmful combustion products are produced
Solution Approach 1:
The patent replaces flame-based combustion heating with electrically-powered Peltier heating elements that provide clean, controlled heating without combustion, eliminating harmful fumes, odors, and combustion byproducts
Solution Approach 2:
The thermoelectric heating elements provide direct, localized heating where needed without the need for external fuel sources or complex flame control mechanisms, making the system self-contained and cleaner
3Temperature
If conventional heated food carts with air circulatory systems are used, then heating is provided, but the cabinets take a long time to reach desired temperature and are relatively inefficient
Solution Approach 1:
The patent extracts the heating and cooling function directly to the food contact surfaces through integrated Peltier elements, eliminating the need for indirect air circulation systems and reducing the time to heat or cool food
Solution Approach 2:
The system pre-cools or pre-heats the food service trays themselves using thermoelectric elements integrated into the tray structure, so that when food is placed on the trays, the desired temperature is already established, reducing overall heating/cooling time
4Temperature
If conventional refrigeration or heating systems are used, then temperature control is provided, but portability is limited
Solution Approach 1:
The patent replaces heavy mechanical refrigeration and heating systems with lightweight solid-state thermoelectric Peltier chips that provide the same temperature control functions with minimal weight, enabling true portability
Solution Approach 2:
The same Peltier chip technology provides both heating and cooling functions by simply reversing the electrical current direction, eliminating the need for separate heating and cooling systems and reducing overall weight
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 efficiently heats or cools food to desired temperatures within 15-20 minutes for warming and under an hour for cooling, maintaining conditions indefinitely, while being portable and safer than traditional methods.
Implementation Method 1
A first manifold may have a plurality of openings, each allowing a seal to be made against a first surface of a Peltier chip and defines a flow path for a heat transfer fluid which directly contacts the first surfaces of the Peltier chip(s)
Implementation Method 2
The fluid then circulates through tubing from the manifold to a separate radiator
Implementation Method 3
One or more fans may be placed to encourage airflow through the radiators and coolant reservoirs
Implementation Method 4
A second opposite manifold also has a plurality of openings, each allowing a seal to be made against a second surface of the Peltier chip(s) to define a flow path for a heat transfer fluid which directly contacts the second surfaces of the plurality of Peltier chip(s)
Data Source
AI summary
Systems for heating or cooling a food service container to an appropriate temperature for service or transport, and cabinets including such systems. A first manifold allows a seal to be made against a first surface of one or more Peltier chips and defines a flow path for a heat transfer fluid which directly contacts the first surfaces of the Peltier chips. The fluid circulates through tubing from the first manifold to a first radiator. A second opposite manifold defines a flow path for a heat transfer fluid which directly contacts the second surfaces of the Peltier chips. The fluid then circulates through tubing from the second manifold to a second radiator. The first radiator may be disposed inside, and the second radiator outside, the cabinet. Application of current in a first direction to the Peltier chips can heat the cabinet and reversal of the current may cool the cabinet.