Heat Pump Fan Grill Spacing to Prevent Icing and Airflow Loss
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Solution Overview
Problem
Heat pumps operating in freezing conditions experience ice buildup and ice-bridging in the fan/orifice ring system, leading to reduced airflow, noise, and decreased heating efficiency, prompting unnecessary service calls.
Innovation Solution
A housing design for outdoor HVAC units with a grill having grill members spaced closer than traditional designs, combined with relief air vents, to reduce ice accumulation and maintain airflow, while adhering to safety standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the grill members are spaced widely to allow airflow, then airflow is improved, but ice buildup occurs between the fan and orifice ring
Solution Approach 1:
The patent introduces an intermediary structure (the grill with closely spaced members) between the fan and the external environment. This intermediary blocks freezing precipitation from directly contacting the fan-orifice ring clearance area, preventing ice buildup while still allowing sufficient airflow through the closely spaced grill members.
Solution Approach 2:
The closely spaced grill members create a preliminary barrier that prevents freezing precipitation from reaching the fan-orifice ring clearance before ice can form. This preliminary protective action stops the harmful freezing process before it can impair fan operation.
2Object-affected harmful factors
If the grill members are spaced closely to prevent ice buildup, then ice protection is improved, but airflow is reduced
Solution Approach 1:
The patent changes the spacing parameter of the grill members from wide (conventional) to close spacing. This parameter change creates a dual effect: it forms a barrier against freezing precipitation while maintaining sufficient airflow through the numerous closely spaced openings, thus resolving the contradiction between ice protection and airflow.
3Reliability
If ice buildup occurs in the fan system, then operation continues, but noise increases due to ice-bridging
Solution Approach 1:
The closely spaced grill members convert the potential harm of freezing precipitation into a beneficial protective barrier. By intercepting the precipitation before it reaches the fan, the grill prevents ice-bridging and the associated noise, while the chilled air discharge through the grill still provides the necessary cooling function.
4Reliability
If ice buildup occurs in the fan system, then operation continues, but heating efficiency decreases due to reduced airflow
Solution Approach 1:
The grill performs a preliminary protective function by preventing ice accumulation before it can impede airflow. This preliminary action ensures that the fan-orifice ring clearance remains free of ice, maintaining optimal airflow conditions and heating efficiency throughout operation.
Data Source
AI summary
A protective housing is provided for a heating, ventilation, and air conditioning (HVAC) unit having a fan therein. The fan comprises a plurality of blades, each blade having a proximal and distal end. The housing comprises a plurality of side panels, each side panel comprising openings enabling airflow into the housing. The housing further comprises an access panel that is coupled between two of the plurality of side panels wherein the access panel and the plurality of side panels form an enclosure. An orifice ring is mounted within the housing, wherein a running clearance between the distal end of the fan blades and the orifice ring has a first spacing. A cover fastens atop the enclosure, the cover comprising a grill having a plurality of grill members, wherein the grill members are separated by a second spacing, the second spacing being smaller than the first spacing.