Abstract:The main aim of the current paper is to demonstrate the capability of a two-phase closed thermosyphon loop system to cool down a contemporary datacenter rack, passively cooling the entire rack, including its numerous servers. The effects on the cooling loop performance with respect to the server orientation, microevaporator design, riser and downcomer diameters, working fluid, and approach temperature at the condenser have been modeled and simulated. The influence of the thermosyphon height (here from 5-20 cm … Show more
“…At evaporation temperature of 70 and 90 • C, accumulated heat was sufficient to vaporize the working substance. As the temperature of the evaporator also increased, the viscosity and density of the working substance in the liquid state decreased which led to vaporization of the working substance [41,42]. Upon applying the evaporation temperature of 70 and 90 • C, as shown in Tab.…”
Section: Effects Of the Aspect Ratio And Evaporator Temperature On Th...mentioning
confidence: 97%
“…Once the liquid working substance reaches the evaporator, it will be heated and the working cycle is repeated [38,41].…”
Section: Behavior Of Flow Patterns Within Rtpctmentioning
This research explored different types of two-phase flow patterns that influenced heat transfer rate by assessing rectangular two-phase closed thermosyphon (RTPCT) made from glass with the sides of equal length of 25.2 mm, aspect ratio 5 and 20, evaporation temperature of 50, 70, and 90 • C, working substance addition rate of 50% by volume of evaporator, and water inlet temperature at condensation of 20 • C. Upon testing with aspect ratios 5, three flow patterns emerged which were: bubble flow, slug flow and churn flow respectively. As per the aspect ratio 20, four flow patterns were discovered which were: bubble flow, slug flow, churn flow and annular flow, respectively. Aspect ratio 5 pertains characteristic which resulted in a shorter evaporation rate of the RTPCT than that of the aspect ratio 20, thus, a shorter flow distance from the evaporator section to heat releaser was observed. Therefore, flow patterns at aspect ratio 5 exhibited a faster flow velocity than that of the aspect ratio 20. Furthermore, changes of flow pattern to the one that is important for heat transfer rate can be easily achieved. Churn flow was the most important type of the flow for
“…At evaporation temperature of 70 and 90 • C, accumulated heat was sufficient to vaporize the working substance. As the temperature of the evaporator also increased, the viscosity and density of the working substance in the liquid state decreased which led to vaporization of the working substance [41,42]. Upon applying the evaporation temperature of 70 and 90 • C, as shown in Tab.…”
Section: Effects Of the Aspect Ratio And Evaporator Temperature On Th...mentioning
confidence: 97%
“…Once the liquid working substance reaches the evaporator, it will be heated and the working cycle is repeated [38,41].…”
Section: Behavior Of Flow Patterns Within Rtpctmentioning
This research explored different types of two-phase flow patterns that influenced heat transfer rate by assessing rectangular two-phase closed thermosyphon (RTPCT) made from glass with the sides of equal length of 25.2 mm, aspect ratio 5 and 20, evaporation temperature of 50, 70, and 90 • C, working substance addition rate of 50% by volume of evaporator, and water inlet temperature at condensation of 20 • C. Upon testing with aspect ratios 5, three flow patterns emerged which were: bubble flow, slug flow and churn flow respectively. As per the aspect ratio 20, four flow patterns were discovered which were: bubble flow, slug flow, churn flow and annular flow, respectively. Aspect ratio 5 pertains characteristic which resulted in a shorter evaporation rate of the RTPCT than that of the aspect ratio 20, thus, a shorter flow distance from the evaporator section to heat releaser was observed. Therefore, flow patterns at aspect ratio 5 exhibited a faster flow velocity than that of the aspect ratio 20. Furthermore, changes of flow pattern to the one that is important for heat transfer rate can be easily achieved. Churn flow was the most important type of the flow for
“…The proposed design bears significant similarities with the well-known thermosiphon cooling systems [17][18][19] in which the refrigerant circulates in winter through the refrigeration circuit due to natural convection through the evaporator and condenser. Similar designs have previously been tested by such manufacturers of refrigeration equipment as Mayekawa [20], Carrier (Aquasnap Puron chillers, USA), and Gea (installation at the Kez Cheese Factory, Russia [21]).…”
The surface of the Earth is a source of radiation of thermal energy, which, passing through the atmosphere, is partially absorbed while the bulk of the energy is released into the surrounding outer space. A cooling technique based on this physical phenomenon is known as radiative cooling (RC). It is possible to reduce the consumption of electricity for cooling, as well as to reduce capital costs, by integrating the unit with radiative cooling directly into the circulation circuit of the refrigerant of the refrigeration machine. An experimental refrigeration system has been designed, in which in the cold periods of the year the removal of heat from the cooled object is carried out due to the mode of natural circulation of the refrigerant from the evaporator to the heat exchanger, cooled by radiative cooling. A refrigeration system with natural circulation and radiative cooling of the refrigerant R134a was experimentally studied during the autumn period in Almaty. The experimental study established that the chamber is cooled with the help of the examined system while the temperature in the cooled volume is maintained by 5...7 K above ambient air temperature at night. The dependence of the air temperature in the refrigerating chamber on the temperature of the atmospheric air has been determined. A procedure for assessing the cooling capacity of the system has been devised.
The study reported here demonstrated the possibility of using radiative cooling to remove heat under the mode of natural circulation of the refrigerant.
The refrigeration system reduces energy consumption in the cold seasons by diverting heat to the environment without the compressor operating
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