Solar-Assisted Water Heating With In-Line Heater Control
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Solution Overview
Problem
Conventional solar assisted water heating systems face inefficiencies in cold climates due to heat losses, clogging, and high costs, with issues like reverse thermo siphoning, scale buildup, corrosion, and the need for glycol in freezing conditions, leading to increased energy consumption and system costs.
Innovation Solution
A solar assisted water heating system with a primary loop and a secondary loop, featuring a solar collector, heat exchanger, in-line water heater, and a system controller that measures transient heat profiles to optimize heating based on flow and temperature, eliminating the need for glycol and reducing energy losses through predictive control and integrated solar thermal storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thermosyphon system is used for solar water heating, then cost effectiveness is improved, but clogging due to scale and corrosion occurs and energy efficiency deteriorates in cold climates
Solution Approach 1:
The system is divided into separate functional components: a solar collector loop and a domestic hot water tank system. This segmentation allows the solar collector to be optimized for thermal collection while the tank system handles water storage and heating, eliminating the need to heat the entire tank in thermosyphon systems and improving energy efficiency.
Solution Approach 2:
A heat exchanger is introduced as an intermediary component between the solar collector loop and the domestic hot water tank. This allows thermal energy transfer without direct fluid mixing, preventing scale and corrosion issues while maintaining cost-effectiveness and improving energy efficiency by enabling selective heating.
2Loss of energy
If the tank is placed inside the dwelling in a combi-system, then heat losses are reduced, but the system complexity increases due to additional heat exchanger stages
Solution Approach 1:
The tank is extracted from the outdoor environment and placed inside the dwelling, removing it from freezing temperatures. This eliminates the need for complex freeze protection systems and additional heat exchanger stages, reducing system complexity while maintaining reduced heat losses.
Solution Approach 2:
The solar collector loop is designed to serve multiple functions: it provides thermal energy for domestic hot water heating and simultaneously acts as a freeze-protected system through its glycol-based circulation. This multi-functionality eliminates the need for additional dedicated freeze protection equipment.
3Reliability
If glycol is used in the solar heat transfer loop to prevent freezing, then freezing protection is improved, but system cost increases and energy efficiency deteriorates
Solution Approach 1:
The system uses a glycol-based heat transfer fluid in the solar collector loop, changing the freezing point parameter of the fluid to below zero. This allows the loop to operate in freezing temperatures without additional energy input for freeze protection, maintaining energy efficiency while providing reliable freezing protection.
4Temperature
If conventional systems heat the full tank to required temperature, then domestic hot water temperature is maintained, but energy consumption increases
Solution Approach 1:
The system applies partial heating action by using the heat exchanger to transfer thermal energy from the solar collector loop to the domestic hot water tank only when and where needed. This allows maintaining required domestic hot water temperature without the excessive energy consumption of heating the entire tank volume, as the heat exchanger enables targeted thermal energy transfer.
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 system provides lower-cost, high-energy-efficiency hot water with quicker response times, reducing heat losses, preventing freezing, and minimizing scale and corrosion, while maintaining user comfort and stability.
Implementation Method 1
a heat exchanger operationally connected to the primary loop and a secondary loop
Implementation Method 2
a solar collector including an input and an output
Implementation Method 3
measuring a transient heat profile of the first temperature in the primary loop
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A system for solar assisted water heating provides hot water to a user at a lower cost, higher energy efficiency, and with a quicker response time than conventional systems, reducing energy losses, and improving user comfort. The basic architecture includes four main components: a solar collector, a heat exchanger, an in-line heater, and a control system. A transient heat profile of a first temperature in a primary loop is measured while a first flow generator G1 is active for the primary loop. Solar assisted heating of water in a secondary loop is provided based on: a flow of water in the secondary loop; a current first temperature; and the transient heat profile of the first temperature by activating: the first flow generator in the primary loop and an in-line water heater in the secondary loop.