Microchannel heat exchangers are gradually being applied in commercial and residential HVAC industries due to their high heat transfer efficiency, compact structure, and cost advantages. Related research is receiving increasing attention from the industry, becoming a research hotspot. This information was learned from a recent lecture by Professor Li Junming from the Department of Thermal Engineering at Tsinghua University.
For the HVAC industry, providing stable, reliable, and energy-efficient products is an important proposition. Simply relying on improving component performance (such as using high-efficiency compressors and fans) or increasing heat exchanger area to improve energy efficiency ratios will inevitably increaseequipment costs, causing waste of non-renewable resources, and increasing purchase costs for consumers.
According to Professor Li Junming, the basic structure of microchannel heat exchangers for air conditioners is multi-pass aluminum strip tubes with corrugated fins (slotted), overall welding and general multi-pass. It has significant effects on low-carbon energy saving while reducing air conditioning manufacturing costs and improving product market competitiveness.
Specifically, its advantages are reflected in: good thermal conductivity, which can effectively reduce fan power; helping to reduce refrigerant charge, which is very important for using flammable natural refrigerants; saving materials and reducing manufacturing costs; and having good corrosion resistance.
However, Li Junming also pointed out that there are key technical difficulties in the research of microchannel heat exchangers, namely how to solve the uniform distribution problem of two-phase refrigerant fluid in sub-channels when used as evaporators, the switching operation problem between cooling and heating conditions, and the removal of defrost water.
Li Qiang, Director of the Technology R&D Center of Midea's Domestic Air Conditioning Division, told reporters that Midea is also committed to researching microchannel heat exchangers for air conditioners and has used this product in small-batch air conditioners for customer testing experiments. Regarding the above technical difficulties，Li Qiang told reporters that there have been some research breakthroughs in solving these problems。
