Laundry Exhaust Heat Recovery for Preheated Wash Water Buffering
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Solution Overview
Problem
Existing methods for recovering energy from the exhaust air of laundry machines operating with warm air face challenges in utilizing the recovered thermal energy efficiently due to its intermittent production and mismatched timing with energy demand, leading to inefficient reuse.
Innovation Solution
The method involves using heat exchangers to preheat treatment liquids for laundry machines, allowing residual energy from exhaust air to be reused for warming or preheating fresh water, which is then stored and used across multiple machines, ensuring continuous preheating even during discontinuous operation of laundry machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If energy is recovered from exhaust air using heat exchangers, then thermal energy can be utilized for preheating treatment liquid, but the intermittent production of exhaust air creates timing mismatches with energy demand
Solution Approach 1:
The system preheats treatment liquid in advance using available exhaust air before it is needed for laundry treatment. By continuously preheating water in the heat exchanger whenever exhaust air is available, the system prepares thermal energy in advance to match future demand, eliminating timing mismatches between energy availability and consumption requirements.
Solution Approach 2:
The system maintains continuous preheating action by continuously circulating water through the heat exchanger whenever exhaust air is available, rather than operating in discrete batches. This continuous operation ensures that thermal energy is constantly being transferred and stored, smoothing out the intermittent nature of exhaust air production and ensuring continuous readiness to meet energy demand.
2Productivity
If exhaust air is used immediately for preheating, then energy recovery efficiency is maximized, but the discontinuous operation of laundry machines limits continuous energy availability
Solution Approach 1:
The system performs preliminary heating of treatment water whenever exhaust air is available, storing this preheated water in a buffer tank. This advance preparation ensures that heated water is ready for immediate use when laundry machines require it, maintaining high energy recovery efficiency while ensuring continuous availability regardless of when exhaust air is produced.
Solution Approach 2:
The heat exchanger system serves multiple functions: it acts as both an immediate heat transfer device when exhaust air is available and as a charging mechanism for a thermal buffer that supplies heat during periods when exhaust air is not available. This multi-functionality allows the system to maintain both high recovery efficiency and continuous availability.
3Use of energy by moving object
If recovered thermal energy is used for its original purpose, then energy efficiency improves, but the temperature and timing may not match the specific requirements of different laundry machines
Solution Approach 1:
The heat exchanger and buffer tank system acts as an intermediary between the exhaust air energy source and the various laundry machines. It decouples the energy recovery process from the energy consumption process, allowing thermal energy to be transferred to water in advance and then distributed to different machines at different times and temperatures as needed, thereby adapting to varying requirements while maintaining overall energy 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 approach enables the effective and economical reuse of energy from exhaust air, reducing the need for additional energy sources and optimizing energy recovery by preheating treatment liquids and laundry items, thus enhancing overall energy efficiency.
Implementation Method 1
energy drawn from a heat exchanger or several heat exchangers of the exhaust air in order to warm up or at least preheat fresh treatment liquid
Implementation Method 2
The use of the energy recovered from the warm exhaust air is problematic because the recovered thermal energy is often needed somewhere else and at a different time
Implementation Method 3
the cooled exhaust air leaving the at least one heat exchanger is fed to at least one dryer or finisher and only then is the exhaust air discharged to the outside. This makes it possible to use the residual energy that is not extracted from the exhaust air by the heat exchanger, for example to preheat cold and damp laundry
Data Source
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AI summary
In laundries, warm exhaust air is produced, for example from dryers (12), which is usually discharged outside unused. The invention provides for the exhaust air of a laundry machine working with hot air, for example a dryer (12), to be routed through a heat exchanger (19), as a result of which cold fresh water is preheated by the energy in the exhaust air, which is used in a laundry serving for the wet treatment Laundry machine, such as a tunnel washing machine (10), is required. As a result, the residual energy in the exhaust air from a laundry machine working with hot air can be reused effectively and, above all, economically for the targeted operation of another laundry machine, namely one that is used for wet treatment of the laundry.