Two-Stage Liquid Heating for High-Flow Low-Power Coffee Brewing
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Solution Overview
Problem
Existing liquid heating devices for hot beverage machines face challenges in achieving high flow rates and pressures efficiently while maintaining low power consumption, particularly in producing both regular and espresso coffee, as current systems are either energy-inefficient or unsuitable for low voltage countries.
Innovation Solution
A liquid heating device utilizing a two-step heating system with a flow-through heater, a first tank for initial liquid storage, a second tank for pre-heating, and a switching unit to manage the heating cycles, pre-heating a portion of the liquid to 35-40 °C and then heating it to 90-95 °C, reducing overall power consumption and enabling operation at lower power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a flow-through heater is used to achieve high flow rates, then the flow rate requirement is met, but the power consumption increases to around 2,100 W which is unsuitable for low voltage countries
Solution Approach 1:
The system pre-heats water in a reservoir before brewing, so that when high flow rate is needed, the water is already warm and requires less power to reach brewing temperature. This preliminary heating action reduces the power demand during actual brewing operations.
Solution Approach 2:
The heating process is divided into two stages: a pre-heating stage that warms water in the reservoir, and a final heating stage that brings water to brewing temperature. This segmentation allows the system to manage power consumption more efficiently by distributing heating load over time.
2Productivity
If a boiler system is used to achieve high flow rates at low pressures, then regular coffee production is optimized, but the system becomes complicated and expensive to manufacture with high safety requirements
Solution Approach 1:
The flow-through heater is designed to handle multiple functions: it can operate at high flow rates for regular coffee and at high pressures for espresso. This multi-functionality eliminates the need for separate boiler systems, reducing overall system complexity and manufacturing costs while maintaining safety.
3Loss of time
If the water reservoir is pre-heated to 40 °C to reduce heating time, then the heating time is reduced, but the energy efficiency decreases especially when coffee is brewed seldom or in small amounts
Solution Approach 1:
Instead of pre-heating the entire reservoir capacity, the system pre-heats only a portion of the water to 40°C. This partial pre-heating reduces energy consumption while still providing enough pre-warmed water to reduce heating time during brewing, achieving a balance between speed and efficiency.
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 allows for high flow rates and pressures with lower power consumption, making it suitable for combined coffee and espresso machines and compatible with low voltage countries, while minimizing energy waste by only heating the amount of liquid needed for the selected beverage.
Implementation Method 1
a flow through heater (18)
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The present invention relates to a liquid heating device (10) for a hot beverage machine, comprising: -a flow through heater (18, 18'); -a first tank (12) for receiving liquid (24) to be heated; -a second tank (14) for temporarily storing pre-heated liquid (24'); -a liquid outlet (22) for releasing heated liquid; and -a switching unit (20, 20', 20'', 20''') which is configured to switch a liquidflow cycle of the liquid heating device (10) between a pre-heating cycle, in which liquid (24) flows from the first tank (12) through the flow through heater (18, 18') and into the second tank (14) in order to temporarily store pre-heated liquid (24') in the second tank (14), and a end-heating cycle, in which the pre-heated liquid (24') flows from the second tank (14) through the flow through heater (18, 18') to the liquid outlet (22).