Decentralized Water Heating Flow Control for Solar Stagnation Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Decentralized water heating systems face inefficiencies due to fluctuating cold water temperatures, leading to increased return temperatures and reduced solar heat input, especially in regions with significant seasonal temperature variations, resulting in heat loss and potential stagnation in solar thermal systems.
Innovation Solution
A method and device that utilize a plate heat exchanger with a proportional controller and temperature sensors to dynamically adjust the flow temperature based on cold water and heating water temperatures, incorporating a mixer and control device to optimize flow temperature control, reducing heat losses and preventing stagnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cold water temperature is recorded at each heat exchanger station with individual controllers, then local control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent consolidates cold water temperature measurement to a single central location in the cold water supply line rather than installing sensors at each heat exchanger station. The control device receives this single temperature signal and adjusts flow temperatures at multiple stations accordingly, reducing system complexity while maintaining effective control.
Solution Approach 2:
The centrally located temperature sensor serves all heat exchanger stations simultaneously. A single measurement point provides universal information about cold water temperature that is used to control multiple decentralized heating units, eliminating the need for redundant sensors at each station.
2Reliability
If flow temperature is increased to prevent stagnation in solar circuits, then solar system reliability is improved, but heat losses in distribution lines increase
Solution Approach 1:
The system dynamically adjusts flow temperature based on real-time conditions. When stagnation risk is detected (high tank temperature), flow temperature is increased to circulate water and prevent overheating. When stagnation is not a risk, flow temperature is reduced to minimize distribution line heat losses. This dynamic adaptation resolves the contradiction between preventing stagnation and reducing energy losses.
Solution Approach 2:
The control device changes the flow temperature parameter in response to stagnation conditions. By adjusting this key parameter based on tank temperature and solar input conditions, the system prevents stagnation when necessary while minimizing energy losses during normal operation.
3Loss of energy
If return temperature is lowered to improve solar thermal system effectiveness, then energy efficiency is improved, but control complexity increases due to fluctuating cold water temperatures
Solution Approach 1:
The control device uses feedback from cold water temperature sensors and tank temperature sensors to automatically adjust flow temperature. This closed-loop control simplifies the management of return temperature by handling the complexity of fluctuating cold water temperatures automatically, maintaining optimal conditions for solar thermal effectiveness without requiring manual intervention.
Solution Approach 2:
The system performs preliminary adjustments to flow temperature based on predicted stagnation conditions. By proactively increasing flow temperature when tank temperature approaches stagnation thresholds, the system prevents the need for more complex reactive control measures and maintains solar thermal effectiveness.
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 solution enhances the effectiveness of decentralized water heating by lowering return temperatures, reducing heat losses, and preventing stagnation, while simplifying the system structure and reducing costs by centralizing temperature recording and minimizing controller interactions.
Implementation Method 1
hot water is only generated in the respective apartment, for example by a heat exchanger station
Implementation Method 2
heating water storage tank to be loaded in particular via a solar circuit
Implementation Method 3
heating circuit connected to it with a pump to at least one heat exchanger station
Data Source
Figure 1
AI summary
The invention relates to a method and a device for decentralized hot water preparation via at least one heat exchanger station (W1, W2), consisting of a plate heat exchanger (1, 1') with a connection on the primary side to a heating circuit with flow and return lines (2, 3), a cold water connection (4) and a hot water connection (5, 5') to a consumer on the secondary side and a proportional controller (6, 6') for setting the primary-side heating water quantity to the secondary-side recorded hot water consumption quantity, with a heating water storage tank to be charged in particular via a solar circuit (8). (9) to which the heating circuit is connected with a pump (11) and with a control device (15). The invention is based on the object of optimizing the control of the flow temperature for decentralized water heating systems, taking into account a strongly fluctuating cold water temperature, and to avoid stagnation in connection with solar systems. The method according to the invention is characterized in that the flow temperature in the heating circuit is regulated via a mixer (10), in that the cold water temperature, the heating water temperature in the heating water storage tank (9) and the flow temperature in the heating circuit are measured, evaluated and converted into a control signal in the control device (15). for the mixer (10) are processed.