Air Handler Water Flow Control to Prevent Pump Cavitation
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Solution Overview
Problem
Conventional systems for heating air using hot water often face issues with inadequate water flow and temperature, leading to cavitation of air handler pumps and reduced energy transfer, resulting in cold air being blown into spaces.
Innovation Solution
A method and system where a controller monitors water flow from a water heater and adjusts the operation of the air handler's pump and blower/fan to ensure sufficient hot water flow, preventing cavitation and maintaining efficient energy transfer by initiating or terminating operations based on detected water flow levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the water heater supplies hot water to the air handler, then heated air can be generated for space heating, but water draw may exceed the water heater's output flow capacity leading to insufficient water flow
Solution Approach 1:
The system performs preliminary action by detecting water flow conditions before initiating the air handler pump operation. The controller monitors water flow indicia from the water heater and only initiates pump operation when sufficient water flow is detected, preventing the problem of insufficient hot water supply before it occurs.
Solution Approach 2:
The system implements feedback by continuously monitoring water flow indicia from the water heater and using this information to control the air handler pump and blower operation. The controller receives feedback about water flow conditions and adjusts system operation accordingly, ensuring heated air is only produced when sufficient hot water is available.
2Temperature
If the air handler pump operates with insufficient water flow, then the pump may cavitate and its life is shortened, but the pump needs to operate to deliver heated air
Solution Approach 1:
The system performs preliminary action by checking water flow conditions before initiating pump operation. The controller detects water flow indicia and only allows the pump to operate when sufficient water flow is present, preventing cavitation and extending pump life before the problem can occur.
Solution Approach 2:
The system uses feedback from water flow indicia monitoring to control pump operation. The controller continuously receives feedback about water flow conditions and adjusts pump operation accordingly, ensuring the pump only runs when sufficient hot water is available, thereby preventing cavitation and maintaining pump reliability.
3Loss of energy
If water flow to the air handler is low or absent, then energy transfer through the heat exchanger is reduced and cold air is blown instead of heated air, but the system should maintain efficient heating
Solution Approach 1:
The system implements feedback by monitoring water flow indicia and using this information to control blower operation. The controller receives feedback about hot water availability and only operates the blower when sufficient hot water is flowing through the heat exchanger, ensuring efficient energy transfer and preventing cold air delivery.
Solution Approach 2:
The system applies partial action by operating the blower only when sufficient hot water flow is detected, rather than running continuously. This ensures that the blower only operates when the heat exchanger is effectively transferring energy, avoiding the waste of energy and the delivery of cold air.
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 adequate water flow and temperature to the air handler, preventing pump cavitation and ensuring heated air is delivered, thereby extending pump life and maintaining desired air temperatures.
Implementation Method 1
a water heater comprising a burner and a water heater exchanger to produce hot water
Implementation Method 2
a water heater exchanger to produce hot water
Implementation Method 3
an air handler comprising a blower/fan and an air handler heat exchanger to generate heated air from hot water
Data Source
AI summary
A method controls an air handler that generates heated air from hot water generated by a water heater. The method includes generating a signal in the presence or absence of an indicia of water flow associated with the water heater; initiating operation of a pump associated with the air handler when the signal indicates that water flow associated with the water heater is at least at a selected level to supply hot water to the air handler sufficient to generate heated air; and/or terminating operation of the pump and/or a blower/fan associated with the air handler when the presence or absence signal indicates that the water flow associated with the water heater is less than the selected level.