Bypass Coolant Loop Defrost for Heat Pump Radiators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Heat pump systems with secondary coolant loops face performance degradation due to ice/frost formation on the outside heat exchanger, as they lack the capability to defrost or de-ice, unlike single-loop systems that can reverse operation to thaw the refrigerant-based heat exchanger.
Innovation Solution
A defrost system is introduced, comprising a bypass coolant loop, a coolant heater, and a solenoid valve, which activates the heater when the system detects operation outside a normal range and ambient temperatures below a certain threshold, ensuring the low temperature radiator is thawed to maintain performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a secondary coolant loop system is used, then the heat pump can operate in both cooling and heating modes efficiently, but ice/frost formation occurs on the outside heat exchanger and cannot be defrosted
Solution Approach 1:
The system separates the refrigerant loop from the coolant loop, with the refrigerant contained in a self-contained unit. This segmentation allows independent control of the defrost function through a bypass coolant loop that can be activated without affecting the primary heating/cooling operation.
Solution Approach 2:
The defrost system activates preemptively based on detected operating conditions (ambient temperature below threshold and operation outside normal range) before frost significantly degrades performance. The coolant heater is turned on in advance to prevent or reverse frost accumulation.
2Reliability
If the heat pump runs in reverse to defrost, then the outside heat exchanger can be thawed, but the system cannot maintain heating or cooling function simultaneously
Solution Approach 1:
The bypass coolant loop acts as an intermediary system that transfers heat to the outside heat exchanger without requiring the heat pump to reverse its primary function. The coolant heater serves as a dedicated defrost mechanism that operates independently from the main heating/cooling cycle.
Solution Approach 2:
The system uses its own coolant circulation infrastructure to service the defrost function. The bypass coolant loop utilizes the existing coolant pump and circulation system, allowing the heat pump to defrost itself without external intervention or mode switching.
3Reliability
If a coolant heater is activated continuously, then the outside heat exchanger remains frost-free, but energy consumption increases
Solution Approach 1:
The coolant heater operates periodically rather than continuously, activated only when sensors detect conditions conducive to frost formation (ambient temperature below threshold and operation outside normal range). This periodic activation maintains effectiveness while minimizing energy consumption during favorable conditions.
Solution Approach 2:
The system incorporates sensors that continuously monitor ambient temperature and heat pump operating conditions, providing feedback to the controller. Based on this feedback, the controller intelligently activates or deactivates the coolant heater, optimizing the balance between frost prevention and energy consumption.
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
The defrost system effectively prevents frost and ice buildup on the outside heat exchanger, ensuring continuous optimal performance of the heat pump system across various ambient conditions by actively thawing the radiator when necessary.
Implementation Method 1
a coolant heater, and a solenoid valve. When in the heating mode, the controller opens or confirms open the solenoid valve in the bypass coolant loop and activates the coolant heater upon detecting operation of the heat pump outside of a predetermined normal operating range
Implementation Method 2
A first secondary coolant loop comprises a low temperature radiator, the low temperature radiator being in thermal communication with the first side heat exchanger of the heat pump
Data Source
AI summary
A cooling and heating system for a motor vehicle comprises a heat pump, a controller, a low temperature radiator in thermal communication with the heat pump, a passenger cabin heat exchanger in thermal communication with the heat pump, and a defrost system comprising a bypass coolant loop in selective fluid communication with the low temperature radiator. When in the heating mode, the controller opens a solenoid valve and activates a coolant heater in the bypass coolant loop upon detecting operation of the heat pump outside of a predetermined normal operating range and upon detecting an ambient temperature below a predetermined temperature. The controller de-activates the coolant heater upon detecting operation of the heat pump within the predetermined normal operating range. The controller may also de-activate close the solenoid upon detecting operation of the heat pump within the predetermined normal operating range.