Heat pipe vaccum tube 14mm condensor

Material quality and cleaning is extremely important to the creation of a good quality heat pipe. If there are any impurities inside the heat pipe it will effect the performance. The purity of the copper itself must also be very high, containing only trace amounts of oxygen and other elements. If the copper contains too much oxygen or other elements, they will leach out into the vacuum forming a pocket of air in the top of the heat pipe. This has the effect of moving the heat pipe's hottest point (of the heat condenser end) downward away from the condenser. This is obviously detrimental to performance, hence the need to use only very high purity copper.

The heat pipe used in our solar collectors comprises two copper components, the shaft and the condenser. Prior to evacuation, the condenser is brazed to the shaft. Note that the condenser has a much larger diameter than the shaft, this is to provide a large surface area over which heat transfer to the header can occur. The copper used is oxygen free copper, thus ensuring excellent life span and performance.

Each heat pipe is tested for heat transfer performance and exposed to 300oC temperatures prior to being approved for use. For this reason the copper heat pipes are relatively soft. Heat pipes that are very stiff have not been exposed to such stringent quality testing, and may form an air pocket in the top over time, thus greatly reducing heat transfer performance.