Tankless Hot Water Recirculation for Cold Burst Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In domestic hot water delivery systems, the water in the hot water line cools down, leading to initial cold bursts when hot water is drawn, especially when the line is embedded under concrete, as existing recirculation methods are ineffective at low flow rates and cannot maintain consistent temperature profiles.
Innovation Solution
A water delivery system with a tankless heater and a circulatory pump having multiple performance levels, where a low-speed circulation maintains hot water temperature during non-use periods and switches to high-speed reheating when needed, using sensors and control devices to manage flow rates and temperature thresholds, and a flow control valve to adapt to varying pipe resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If recirculation is used to maintain hot water temperature in the hot water line, then the temperature consistency is improved, but the energy consumption increases due to continuous heating operation
Solution Approach 1:
The circulatory pump operates with variable performance levels (first, second, and third levels) rather than continuous operation. The control device dynamically adjusts the pump performance based on temperature sensor feedback, switching between these levels to maintain temperature while minimizing energy consumption during different operational phases.
Solution Approach 2:
The system employs periodic recirculation cycles with pause times instead of continuous operation. During pause times, the pump stops or reduces operation, allowing the system to maintain temperature consistency while reducing overall energy consumption compared to continuous recirculation.
2Temperature
If continuous high-speed recirculation is used to prevent cooling, then the temperature consistency is improved, but the water flow rate and energy efficiency deteriorate
Solution Approach 1:
The circulatory pump switches between different performance levels based on system needs. The first performance level provides low-speed circulation for temperature maintenance during idle periods, while the second performance level provides high-speed recirculation when temperature drops or demand increases, optimizing both temperature consistency and water flow efficiency.
Solution Approach 2:
The system changes the operational parameters of the circulatory pump dynamically. By adjusting the pump performance level based on temperature sensor readings and system state, the patent optimizes the balance between temperature maintenance and water flow efficiency, avoiding continuous high-speed operation that would waste energy and reduce overall system productivity.
3Loss of energy
If the hot water line is embedded under concrete for insulation, then the thermal insulation is improved, but the temperature uniformity deteriorates due to spatially uneven cooling
Solution Approach 1:
The temperature sensor is strategically positioned in the hot water line to detect temperature drops caused by uneven cooling under concrete. This extraction of temperature information allows the control system to identify and respond to localized cooling issues, maintaining overall temperature uniformity despite the insulating concrete embedding.
Solution Approach 2:
The control device uses feedback from the temperature sensor to monitor temperature uniformity in the hot water line. When the sensor detects temperature drops in specific sections (particularly under concrete), the control device adjusts the circulatory pump performance to compensate, ensuring uniform temperature distribution throughout the line despite the insulating concrete embedding.
4Use of energy by moving object
If the circulatory pump operates at low flow rate to minimize energy consumption, then the energy efficiency is improved, but the reheating capability deteriorates
Solution Approach 1:
The circulatory pump dynamically adjusts its performance level based on system conditions. During normal operation, it runs at the first performance level for energy efficiency. When temperature drops or hot water demand increases, the control device switches to the second performance level for rapid reheating, thus balancing energy efficiency with reheating capability throughout the operational cycle.
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 ensures consistent hot water supply by maintaining minimal temperature variation in the hot water line, preventing cold bursts and quick reheating when needed, improving comfort and efficiency by automatically adjusting pump performance based on temperature and usage patterns.
Implementation Method 1
water can be circulated at the first performance level with constant low speed
Implementation Method 2
a tankless heater device for heating water
Implementation Method 3
the circulatory pump comprises a control device which switches between the first performance level and the second performance level
Data Source
AI summary
A water delivery system is provided, comprising at least one faucet device with a cold water faucet part and a hot water faucet part, a cold water line to the at least one faucet device, a tankless heater device for heating water, a hot water line having a first portion running from an outlet of the tankless heater device to the at least one faucet device and having a second portion running from the at least one faucet device to an inlet of the tankless heater device, and a circulatory pump arranged in the second portion of the hot water line, wherein the circulatory pump has a prefixed first performance level and a prefixed second performance level, wherein the first performance level causes a finite water flow in the hot water line which is below an operation threshold value of the tankless heater device.