Low-pressure heat pipes and heat transfer methods using low-pressure for heat pipes
Heat pipes and low-pressure working fluids used for heat pipes are described, by charging the low pressure working fluids with a level of non-condensable gases of less than 1% by volume, and the heat pipes can provide better thermal performance than aluminum plates while little or no additional cost is introduced for degassing.
1. A method of transferring heat in a heat pipe comprising:
(a) providing a heat pipe having evaporator section and a condenser section with a gaseous heat transfer composition in the condenser section, said gaseous heat transfer composition in the condenser section having a percent by volume of total non-condensable gases (NCG) of from 0.2% to not greater than 1%; and
(b) transferring heat from said heat pipe by condensing said gaseous heat transfer composition in said condenser section, wherein said heat pipe operates with a temperature differential of less than 5° C.
2. The method of claim 1 wherein said gaseous heat transfer composition in the condenser section has a percent by volume of total non-condensable gases (NCG) of not greater than 0.75% and wherein said heat pipe operates with a temperature differential of less than 4° C.
3. The method of claim 1 wherein said gaseous heat transfer composition in the condenser section has a percent by volume of total non-condensable gases (NCG) of not greater than 0.5%, and wherein said heat pipe operates with a temperature differential of less than 3.5° C.
4. The method of claim 1 wherein said gaseous heat transfer composition in the condenser section has a percent by volume of total non-condensable gases (NCG) of from about 0.2% to less than about 0.5% and wherein said heat pipe operates with a temperature differential of less than 3.5° C.
5. The method of claim 4 wherein said gaseous heat transfer composition is selected from the group consisting of cisR1224yd, R1233zd(E), R1336mzz(Z), R1336mzz(E), R1234ze(Z), iso-pentane, HFE-7100, HFE-7000, HFE-649 and combinations of these.
6. The method of claim 1 wherein said gaseous heat transfer composition is a low-pressure working fluid.
7. An electronic component cooled using the method according to claim 4 .
8. An electrical/electronic system that has at least one component cooled using the method according to claim 4 .
9. An electrical/electronic system of claim 8 selected from LED TV, 5G Active Antenna Unit, 5G Base Band Unit, high power density chips or IGBT.
10. The method of claim 1 wherein said gaseous heat transfer composition is a high pressure working fluid.
11. A method of transferring heat in a heat pipe comprising:
a) providing a heat pipe having evaporator section and a condenser section with a gaseous heat transfer composition in the condenser section, said gaseous heat transfer composition in the condenser section being selected from the group consisting of cisR1224yd, R1233zd(E), R1336mzz(Z), R1336mzz(E), R1234ze(Z), iso-pentane, HFE-7100, HFE-7000, HFE-649 and combinations of these, wherein said heat transfer composition has a percent by volume of total non-condensable gases (NCG) from about 0.2% to about 0.8% by volume(b) transferring heat from said heat pipe by condensing said gaseous heat transfer composition in said condenser section.
12. An electronic component cooled using the method according to claim 11 .
13. A printed circuit board having at least one component thereon, wherein said electronic component is cooled by the method according to claim 11 .
14. An electronic system that has at least one component cooled using the method according to claim 11 .
15. An electronic system of claim 14 selected from LED TV, 5G Active Antenna Unit, 5G Base Band Unit, high power density chips or IGBT.
16. A cooled electronic component comprising a heat pipe, said heat pipe having evaporator section in thermal communication with the electronic component and a condenser having a gaseous heat transfer composition therein, said gaseous heat transfer composition in the condenser section having a percent by volume of total non-condensable gases (NCG) of from about 0.2% to less than about 0.5%.
17. The cooled electronic component of claim 16 wherein said gaseous heat transfer composition is selected from the group consisting of R1233zd(E), R1336mzz(Z), R1336mzz(E), R1234ze(Z), iso-pentane, HFE-7100, HFE-7000, HFE-649 and combinations of these.
18. A printed circuit board comprising the cooled electronic component of claim 17 .
19. The printed circuit board of claim 18 wherein said cooled electronic component is selected from an LED, a 5G Active Antenna Unit, a 5G Base Band Unit, a high power density chip and/or IGBT.