Hot water recirculation system
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Solution Overview
Problem
Existing hot water recirculation systems in buildings are inefficient in terms of energy and water usage, as they either continuously circulate hot water, leading to energy waste, or require manual activation, which can cause wear and tear on pumps and inefficiency.
Innovation Solution
A demand-driven hot water recirculation system with a flow switching module that automatically diverts and reheats water to plumbing fixtures when the temperature is below a set-point, using a pump only when needed, and integrating ergonomic mixing valves for intuitive operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If hot water is continuously circulated through the plumbing system, then hot water is quickly available at fixtures, but energy is wasted heating water that sits in pipes acting as radiators
Solution Approach 1:
The system performs preliminary action by circulating hot water through the plumbing system before it is actually needed. The microprocessor controller monitors water temperature at fixtures and activates the recirculation pump in advance to preheat the water in the pipes, ensuring hot water is immediately available when the fixture is turned on, while avoiding continuous operation to reduce energy waste
2Loss of time
If a recirculation pump is operated continuously to maintain hot water availability, then hot water is quickly accessible at fixtures, but the pump experiences excessive wear and tear
Solution Approach 1:
The system applies dynamics by transitioning the recirculation pump from continuous operation to variable, demand-driven operation. The microprocessor controller dynamically adjusts pump operation based on real-time temperature monitoring at fixtures, activating the pump only when hot water is needed and deactivating it when temperature requirements are met, thereby reducing mechanical wear while maintaining hot water availability
Solution Approach 2:
The system implements feedback by using temperature sensors at the fixtures to monitor water temperature and providing this information to the microprocessor controller. The controller uses this feedback to intelligently control the recirculation pump, activating it only when the monitored temperature falls below the desired threshold, thus reducing unnecessary pump operation and wear while ensuring hot water is available when needed
3Adaptability or versatility
If tankless water heaters are installed far from fixtures to save space, then installation flexibility is improved, but cold water in the pipes must be displaced before hot water arrives
Solution Approach 1:
The system applies preliminary action by circulating hot water from the distant tankless heater through the entire plumbing system in advance. The microprocessor controller monitors temperature at remote fixtures and activates the recirculation pump to preheat the water in the long pipe runs, ensuring that when a fixture is turned on, hot water is immediately available despite the heater's distant location
Solution Approach 2:
The recirculation pump acts as an intermediary device that bridges the gap between the distant tankless water heater and the remote fixtures. It actively transports hot water through the plumbing system and works in conjunction with the temperature monitoring and control system to eliminate the cold water wait time problem that would otherwise result from the heater's distant installation location
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
Minimizes water and energy loss by selectively recirculating hot water only when needed, reducing pump wear and enhancing user convenience through ergonomic controls.
Implementation Method 1
a water heater installed in a house or other building
Implementation Method 2
a pump connected to the return piping for returning water from one or more hot water plumbing fixtures to the water heater
Implementation Method 3
The flow switching module can selectively supply water from the hot water supply piping either to the hot water plumbing fixture or divert water to the return piping for return to the water heater
Implementation Method 4
Water which is diverted to the return piping is reheated by the water heater and then resupplied to the flow switching module
Data Source
AI summary
A hot water recirculation system for a house or other building causes water to be recirculated to a water heater for reheating until the water is above a set-point temperature at which time the heated water is made available for use at a faucet or other hot water plumbing fixture. Recirculation of hot water takes place only when there is demand for hot water at a hot water plumbing fixture. A flow switching module for use in the hot water recirculation system can selectively direct water supplied to the flow switching module from a water heater either to a hot water plumbing fixture or to return piping for returning the water to the water heater. The flow switching module may be operated manually, automatically, or semi-automatically.