Method for operating a hybrid combined-heating device and hybrid combined-heating device
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Solution Overview
Problem
Existing hybrid combination heaters face challenges in preventing icing on heat pump heat exchangers during operation, particularly in modes where heat withdrawal occurs, which can lead to reduced efficiency and potential damage.
Innovation Solution
A control unit is implemented to recognize the risk of icing on heat pump heat exchangers and switch the heating water flow through a bypass, ensuring a minimum volume flow of heating water to prevent icing and maintain sufficient heat supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heat pump operates in defrost mode to remove frost accumulation, then the heat exchanger surface is cleaned and efficiency is restored, but the heat exchanger temperature drops below freezing causing water to freeze and potentially damage the system
Solution Approach 1:
The control unit detects the risk of icing before it occurs during defrost mode operation and proactively switches the valve device to redirect heating water through the bypass, preventing ice formation on the heat exchanger surfaces before they can accumulate and cause damage
Solution Approach 2:
The valve device acts as an intermediary mechanism that switches between two flow paths: the normal heating water circuit and the bypass with drinking water heat exchanger, enabling the system to protect the heat pump heat exchanger from icing by redirecting warm water through the bypass during defrost mode
2Productivity
If the heating water flow is directed through the heating water circuit to provide heat to the building, then building heating is maintained, but the heat pump heat exchanger may not receive sufficient warm water flow during defrost mode leading to icing
Solution Approach 1:
The valve device dynamically switches between two operational modes based on real-time conditions: during normal operation, heating water flows through the building heating circuit; during detected defrost mode with icing risk, the valve redirects flow through the bypass with the drinking water heat exchanger, ensuring continuous protection against icing while maintaining heating capability
3Reliability
If a bypass with drinking water heat exchanger is used to prevent icing, then heat pump reliability is improved, but the device complexity increases due to additional valve switching mechanisms
Solution Approach 1:
The bypass with the drinking water heat exchanger serves multiple functions: it provides an alternative heating path for the building and simultaneously acts as a protective measure against icing during defrost mode, eliminating the need for separate protective heating elements and reducing overall system complexity despite the added valve mechanism
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 icing on heat pump heat exchangers by ensuring a continuous flow of heated water, maintaining the operational efficiency of the heat pump and preventing potential damage.
Implementation Method 1
A heat generator and/or a heat pump heat exchanger connected in series with it in a heating water line control the temperature of the heating water flow
Implementation Method 2
a heat pump heat exchanger connected in series with it in a heating water line control the temperature of the heating water flow, wherein the heat pump heat exchanger can be connected to a heat pump on the secondary side
Implementation Method 3
a bypass with a drinking water heat exchanger arranged hydraulically parallel to the heating water circuit
Data Source
Figure 1~2
AI summary
The invention relates to a method for operating a hybrid combination heating appliance (200) for tempering a heating water flow (1) and a domestic hot water flow (2). A heat generator (206) and/or a heat pump heat exchanger (202) connected in series with it in a heating water circuit (208) temper the heating water flow (1), wherein the heat pump heat exchanger (202) can be connected to a heat pump (300) on the secondary side. The heating water flow (1) flows into a connectable, building-side section of a heating water circuit (400) or into a hydraulically parallel bypass (214) of the hybrid combination heating appliance (200) with a domestic hot water heat exchanger (216), wherein a valve device (220) directs the heating water flow (1) into the heating water circuit (400) or into the bypass (214).It is proposed that a control unit (204) detects a risk of icing at the heat pump heat exchanger (202) and/or at another heat exchanger (308) of the heat pump (300) and switches the valve assembly (220) depending on the detected risk of icing so that the heating water flow (1), in particular coming from the heat generator (206), flows through the bypass (214) and the heat pump heat exchanger (202). The heating water flow (1) is in particular greater than or equal to a predefinable minimum flow rate.