Latent heat storage system having a latent heat storage device and method for operating a latent heat storage system
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Solution Overview
Problem
The existing latent heat storage systems face efficiency issues due to limited heat transfer between the heat transfer medium and the storage medium, leading to premature shutdown of the heat pump when the ice storage is thermally discharged, reducing system efficiency.
Innovation Solution
A latent heat storage system with a coupling device that temporarily introduces a second heat transfer medium heated by a heat source into the connecting line between the extraction heat exchanger and the heat pump, allowing for increased flow temperature and continued operation even when the storage medium is largely or completely solidified.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the latent heat storage device is operated until the storage medium is completely solidified, then the operational duration is extended, but the heat transfer efficiency deteriorates and the heat pump must shut down
Solution Approach 1:
A coupling device is introduced as an intermediary between the extraction heat exchanger and the heat pump. This coupling device includes a mixing chamber that combines the first heat transfer medium (from the extraction heat exchanger) with a second heat transfer medium (from a heat source) to maintain the flow temperature above the critical shutdown level, allowing continuous operation even when the storage medium is completely solidified
2Quantity of substance
If the ice storage has a high icing level, then the storage capacity is increased, but the heat transfer between the heat transfer medium and storage medium is limited causing severe subcooling
Solution Approach 1:
The coupling device acts as a mediator that prevents severe subcooling by mixing warmer second heat transfer medium with the first heat transfer medium before it enters the heat pump, maintaining the flow temperature above the critical level even when the storage medium is completely solidified
3Reliability
If the flow temperature drops below the critical temperature, then the heat pump shuts off to protect itself, but this reduces the system efficiency and operational continuity
Solution Approach 1:
The coupling device performs preliminary action by pre-heating the first heat transfer medium through mixing with the second heat transfer medium before it reaches the heat pump, ensuring the flow temperature remains above the critical shutdown level and preventing unnecessary shutdowns
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 configuration enables the heat pump to operate longer and supply heat to consumers by maintaining a flow temperature above critical levels, even when the latent heat storage device is thermally discharged, thereby enhancing system efficiency and extending operational periods.
Implementation Method 1
A heat transfer medium is then applied to the flow of the heat pump, which has a temperature which is higher than the temperature which the first heat transfer medium has at the outlet of the extraction heat exchanger in the direction of the heat pump. The first heat transfer medium can be mixed with the warmer second heat transfer medium of the at least one heat source and can be heated in this way.
Implementation Method 2
The heat transfer medium of the extraction heat exchanger reaches the flow of a heat pump, which generates a higher temperature level at its outlet from the supplied low-calorific heat.
Implementation Method 3
an ice storage system, in which an extraction heat exchanger extracts heat from an ice storage during the heating period until the ice storage is thermally discharged
Implementation Method 4
When the ice store is thermally discharged, a predetermined volume around the extraction heat exchanger has completely solidified into ice
Data Source
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AI summary
The invention relates to a latent heat storage system (100) comprising: at least one latent heat storage device (10) which contains a storage medium (20) with latent heat; at least one heat pump (104) coupled to the latent heat storage device (10); at least one extraction circuit (30) which has a first heat transfer medium (34) and with which, during normal operation, in accordance with the intended purpose, heat can be extracted from the storage medium (20) and supplied to the heat pump (104) on the input side; and an extraction heat exchanger (32) which is in contact with the storage medium (20), wherein the extraction heat exchanger (32) is connected to the extraction circuit (30). Between the extraction heat exchanger (32) and the heat pump (104), a coupling device (50) is provided in a connection line (112) which at least intermittently supplies a second heat transfer medium (44), which can be heated by at least one heat source (102), into a portion (113) of the connection line (112). The invention also relates to a method for operating a latent heat storage system (100).