Heat supply system
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Solution Overview
Problem
Conventional heat pump water heaters face issues with temperature undershooting and overshooting due to the activation and deactivation of electric heaters, particularly when the length of the flow path between the refrigerant-water heat exchanger and the heating device is significant, leading to inconsistent hot water temperatures.
Innovation Solution
A heat supply system that includes a pump, a first heating device, a second heating device, and a controller that reduces the heating power of the first heating device before activating the second heating device, ensuring stable temperature control by adjusting the heating power of the main heat source when the auxiliary heat source is activated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electric heater is turned OFF to save energy, then energy consumption is reduced, but the temperature of supplied hot water may undershoot
Solution Approach 1:
The controller performs preliminary action by turning on the electric heater before the heating medium temperature reaches the lower threshold, rather than waiting for the temperature to drop and then reacting. This proactive approach ensures the heater is already operating when needed, preventing temperature undershoot while avoiding unnecessary energy consumption by shutting it off before the upper threshold is reached.
2Temperature
If the electric heater is turned ON from OFF state to maintain temperature, then hot water temperature stability is improved, but the temperature of supplied hot water may overshoot
Solution Approach 1:
The controller applies preliminary anti-action by turning off the electric heater before the heating medium temperature reaches the upper threshold. This preemptive shutdown prevents the temperature from overshooting the target value, as the heater is already off when the temperature begins to drop after circulation, eliminating the harmful overshoot effect.
3Adaptability or versatility
If the flow path length between heat exchanger and heating device is increased, then system design flexibility is improved, but heat loss during transport increases
Solution Approach 1:
The controller uses feedback from temperature detectors positioned at strategic locations to monitor the heating medium temperature throughout the system. By detecting temperature changes in real-time and adjusting the electric heater operation accordingly, the system compensates for heat loss in longer flow paths, maintaining temperature stability despite increased transport distance or design flexibility.
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 effectively prevents temperature undershooting and overshooting, maintaining consistent hot water temperatures by synchronizing the heating power adjustments between the main and auxiliary heat sources, thus ensuring reliable temperature control.
Implementation Method 1
a pump configured to pump a heating medium
Implementation Method 2
a first heating device configured to heat the heating medium
Implementation Method 3
a second heating device configured to heat the heating medium downstream of the first heating device
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A heat supply system includes a pump configured to pump a heating medium, a first heating device configured to heat the heating medium, a second heating device configured to heat the heating medium downstream of the first heating device, and a controller configured to perform a first operation and a second operation sequentially after activation of the first heating device, in the case where the first heating device is activated without operating the second heating device. In the first operation, the temperature of the heating medium downstream of the first heating device and upstream of the second heating device is controlled so as to converge to a target value. In the second operation, the temperature of the heating medium downstream of the second heating device is controlled so as to converge to a target value.