Refrigerated display appliances
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Solution Overview
Problem
Conventional open-fronted multi-deck refrigerated display cabinets suffer from ineffective air curtain sealing, leading to cold air spillage, poor temperature control, and high infiltration rates, which result in energy inefficiency and microbial activity, compromising food storage quality.
Innovation Solution
The design features a reduced-height air curtain with a discharge and return airflow system that is unsupported by supplementary cooling, utilizing a discharge outlet and inlet positioned to minimize entrainment of ambient air, and adjustable shelves to optimize airflow management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional air curtain is used to seal the access opening, then cold air containment is improved, but ambient air entrainment increases and energy consumption rises
Solution Approach 1:
The patent changes the velocity parameter of the air curtain from high to low (0.5-2.0 m/s), and adjusts the temperature parameter (5-15°C cooler than ambient). This creates a slow-moving, temperature-stratified air curtain that contains cold air through buoyancy forces rather than high velocity, significantly reducing ambient air entrainment while maintaining effective sealing
Solution Approach 2:
The air curtain is designed to be dynamic and adaptive, with velocity and temperature profiles that naturally stratify the air flow. The system uses the density difference between cold and warm air to create a stable, self-regulating curtain that adjusts to ambient conditions, improving containment without increasing entrainment
2Loss of energy
If high velocity air curtain is used to seal the access opening, then cold air containment is improved, but shopper comfort deteriorates
Solution Approach 1:
The patent reduces the air curtain velocity parameter to 0.5-2.0 m/s, which is barely perceptible to shoppers. This low velocity is sufficient when combined with temperature stratification to maintain effective sealing, eliminating the unpleasant cold wind sensation while preserving cold air containment
3Stability of the object's composition
If supplementary cooling airflow is added to support the air curtain, then air curtain stability is improved, but energy consumption increases
Solution Approach 1:
The patent extracts and eliminates the supplementary cooling airflow system from the conventional design. By relying on the temperature difference and buoyancy forces alone, the system achieves stable air curtain formation without the additional energy-consuming back panel airflow, reducing total cooling energy consumption
4Use of energy by moving object
If the air curtain is reduced in height and unsupported by supplementary cooling, then energy efficiency is improved, but temperature control precision deteriorates
Solution Approach 1:
The patent uses temperature stratification as the primary control mechanism, maintaining a temperature difference of 5-15°C between the air curtain and ambient air. This temperature parameter control, combined with low velocity (0.5-2.0 m/s), creates a stable thermal boundary that effectively seals the access opening and maintains precise temperature control in the display space without supplementary cooling
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 significantly reduces ambient air entrainment, maintains tight temperature control, and enhances energy efficiency, reducing energy consumption and microbial activity while maintaining open-front access for product visibility and accessibility.
Implementation Method 1
The stack effect arises from pressure forces acting on the curtain due to the effect of temperature on the buoyancy of air. Denser, cooler air sinks within the cabinet and so increases pressure within the lower part of the cabinet, pushing the air curtain outwardly away from the cabinet as the curtain descends.
Implementation Method 2
a cooling means for introducing or producing cold air to refrigerate items in the product display space in use
Data Source
AI summary
A refrigerated display unit having an open-fronted cabinet providing a product display space accessible through an access opening provided by the open front. Cooling means produces cold air to refrigerate items in the product display space. A cold air curtain is provided across the access opening using a forwardly-positioned discharge outlet communicating with a supply duct and a forwardly-positioned return inlet in communication with a return duct receiving air from the air curtain. The air curtain is substantially unsupported by the any supplementary cooling airflow supplied into the product display space separately from the air curtain.