Thermal characteristics of a compact LED luminaire with a cooling system based on heat pipes

2020 ◽  
Vol 18 ◽  
pp. 100549 ◽  
Author(s):  
D.V. Pekur ◽  
V.M. Sorokin ◽  
Yu.E. Nikolaenko
2020 ◽  
Vol 23 (04) ◽  
pp. 415-423
Author(s):  
D.V. Pekur ◽  
◽  
V.M. Sorokin ◽  
Yu.E. Nikolaenko ◽  
V.P. Kostylyov ◽  
...  

Widespread use of energy-saving LED lighting systems powered by renewable energy sources, solar energy in particular, will contribute to the improvement of global ecology. One of the structural elements of such lighting systems is LED luminaire. The authors of this article perform a first ever experimental study of electro-optical characteristics of the basic version of a compact high-power LED luminaire for indoor use. The particular feature of this lighting device is that its cooling system for the LED light source is based on heat pipes and concentric cooling rings. Such design allows ensuring the required cooling efficiency of the LED matrix. The revealed trends in optical and electrical parameters during temperature stabilization indicate that the proposed cooling system is highly efficient in maintaining normal thermal conditions of LED light sources with a power of up to 140.7 W and a luminous flux of up to 15083 lm. The results on determining spatial distribution of luminous flux of these luminaires indicate that they may be used for lighting large rooms with high ceilings. Scaling the basic modular design version of the cooling system allows increasing the power of the LED light source up to 600 W.


2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110208
Author(s):  
Yuan Zhang ◽  
Lifeng Wang ◽  
Yaodong Zhang ◽  
Yongde Zhang

The thermal deformation of high-speed motorized spindle will affect its reliability, so fully considering its thermal characteristics is the premise of optimal design. In order to study the thermal characteristics of high-speed motorized spindles, a coupled model of thermal-flow-structure was established. Through experiment and simulation, the thermal characteristics of spiral cooling motorized spindle are studied, and the U-shaped cooled motorized spindle is designed and optimized. The simulation results show that when the diameter of the cooling channel is 7 mm, the temperature of the spiral cooling system is lower than that of the U-shaped cooling system, but the radial thermal deformation is greater than that of the U-shaped cooling system. As the increase of the channel diameter of U-shaped cooling system, the temperature and radial thermal deformation decrease. When the diameter is 10 mm, the temperature and radial thermal deformation are lower than the spiral cooling system. And as the flow rate increases, the temperature and radial thermal deformation gradually decrease, which provides a basis for a reasonable choice of water flow rate. The maximum error between experiment and simulation is 2°C, and the error is small, which verifies the accuracy and lays the foundation for future research.


Author(s):  
Osamu Suzuki ◽  
Atsuo Nishihara

A novel electronics cooling system that uses water heat pipes under an ambient temperature range from −30°C to 40°C has been developed. The system consists of several water heat pipes, air-cooled fins, and a metal block. The heat pipes are separated into two groups according to the thermal resistance of their fins. One set of heat pipes, which have fins with higher thermal resistance, operates under an ambient temperature range from −30°C to 40°C. The other set, which have lower resistance, operates from 0°C to 40°C. A prediction model based on the frozen-startup limitation of a single heat pipe was first devised and experimentally verified. Then, a prediction model for the whole-system was formulated according to the former model. The whole-system model was used to design a prototype cooling system, and it was confirmed that the prototype has a suitable cooling performance for an environmentally friendly electronics cooling system.


Author(s):  
Wei Minghui ◽  
Cai Wei ◽  
Xu Mingze ◽  
Deng Shuang

Abstract Downhole high temperature environment is an important factor affecting the performance of downhole instrument electronic system.At present, various active cooling technologies and passive cooling technologies have been proposed to reduce the temperature of downhole electric circuit system.However, passive cooling technologies can only provide limited cooling capacity for drilling tools under high temperature environment, and the duration of cooling is short, which can not meet the long-time drilling task.This paper presents an Active cooling system(ACS)for downhole electronics and the effects of different temperatures on the performance of electronic components are analyzed.The ACS mainly includes a micro supercharger, condenser tube, evaporation pipe, capillary tube and refrigerant.The theoretical analysis of heat transfer and refrigerant capacity in high temperature environment is carried out.The thermal characteristics of the ACS is evaluated experimentally.The results show that the temperature of electronic components can be reduced to below 163°C in the 200°C downhole environment and components.The geomagnetic field data measured by electronic components at room temperature, 200 °C and with ACS are compared.The results show that ACS can keep electronic components working normally.


Author(s):  
Mayumi Ouchi ◽  
Yoshiyuki Abe ◽  
Masato Fukagaya ◽  
Takashi Kitagawa ◽  
Haruhiko Ohta ◽  
...  

Energy consumption in data centers has seen a drastic increase in recent years. In data centers, server racks are cooled down in an indirect way by air-conditioning systems installed to cool the entire server room. This air cooling method is inefficient as information technology (IT) equipment is insufficiently cooled down, whereas the room is overcooled. The development of countermeasures for heat generated by IT equipment is one of the urgent tasks to be accomplished. We, therefore, proposed new liquid cooling systems in which IT equipment is cooled down directly and exhaust heat is not radiated into the server room. Three cooling methods have been developed simultaneously. Two of them involve direct cooling; a cooling jacket is directly attached to the heat source (or CPU in this case) and a single-phase heat exchanger or a two-phase heat exchanger is used as the cooling jacket. The other method involves indirect cooling; heat generated by CPU is transported to the outside of the chassis through flat heat pipes and the condensation sections of the heat pipes are cooled down by coolant with liquid manifold. Verification tests have been conducted by using commercial server racks to which these cooling methods are applied while investigating five R&D components that constitute our liquid cooling systems: the single-phase heat exchanger, the two-phase heat exchanger, high performance flat heat pipes, nanofluid technology, and the plug-in connector. As a result, a 44–53% reduction in energy consumption of cooling facilities with the single-phase cooling system and a 42–50% reduction with the flat heat pipe cooling system were realized compared with conventional air cooling system.


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