Radiation Cooling Research Articles

Numerical Experiments on Radiative Cooling and Collapse in Plasma Focus Operated in Krypton

The Plasma Focus has wide-ranging applications due to its intense radiation of SXR, XR, electron and ion beams and fusion neutrons when operated in deuterium. The 5-phase Lee Model code has been developed for the focus operated in various gases including D, D–T, He, Ne, N, O, Ar, Kr and Xe. Radiation-coupled motion is included in the modelling. In this paper we look at the effect of radiation cooling and radiation collapse in krypton. The Pease–Braginskii current is that current flowing in a hydrogen pinch which is just large enough for the Bremsstrahlung to balance Joule heating. This radiation-cooled threshold current for a hydrogen pinch is 1.6 MA. It is known that in gases undergoing line radiation strongly the radiation-cooled threshold current is considerably lowered. We show that the equations of the Lee Model code may be used to compute this lowering. The code also shows the effect of radiation cooling leading to radiative collapse. Numerical experiments based on experimentally fitted model parameters are run to demonstrate a regime in which radiation collapse is observed in Kr at a pinch current of 50–100 kA.

A212 太陽熱、長波長放射熱、及び空気熱を熱源とする冷温熱供給ヒートポンプの運転特性(OS-7: 次世代ヒートポンプ・冷凍システム(5))

A212 太陽熱、長波長放射熱、及び空気熱を熱源とする冷温熱供給ヒートポンプの運転特性(OS-7: 次世代ヒートポンプ・冷凍システム(5))

1D Model Study on the Effect of Impurity Radiation Cooling in LHD SOL Plasma

Increasing heat load to plasma-facing walls in future fusion devices and reactors could exceed the engineering limit of the material if simple scaling is applied in size of device to realize sufficient energy confinement time. One of possible means to remove the heat in plasma is impurity gas puffing. In order to investigate the plasma response to the radiation cooling, a one dimensional steady-state two-fluid model has been developed to describe SOL plasma of LHD. Model equations were solved numerically for various neon density and three types of SOL plasma. Maximum neon density above which plasma does not sustain is found. Significant reduction of temperature and heat flux onto the divertor plate are found. It is confirmed that the neon gas puffing is an effective technique to reduce the heat load onto divertor plates.

806 LED照明の発熱に対する放射冷却技術の開発について(G01-2 熱伝達II,G01 熱流体部門)

806 LED照明の発熱に対する放射冷却技術の開発について(G01-2 熱伝達II,G01 熱流体部門)

G060056 LED電球の発熱に対する放射冷却効果に関する研究

G060056 LED電球の発熱に対する放射冷却効果に関する研究

Nocturnal Radiation Cooling Tests

The sun radiates heat to earth in the day. At night the reverse happens when the warmer earth radiates heat to the cold night sky. Roofs of buildings radiate heat day and night at a rate of up to 75 watts per square meter. During the day, this is offset by solar radiation gains on the roof, however, at night, this heat loss has the ability to cool air as roofs can experience a temperature drop of 6 to 20°C below ambient.Cooling a building by long-wave radiation to the night sky has long been identified as a potentially productive means to reduce space cooling energy in buildings but the technology has not been commercially available. A series of tests have been completed at Canada's National Solar Test Facility and data shows that it is possible cool air a few degrees below ambient from sunset to sunrise using a perforated metal panel system mounted onto a sky facing surface.This paper will summarize the night cooling tests, compare the data with published material from ASHRAE and suggest methods for utilizing nocturnal radiation to cool buildings.

D33 SRF(Super Resonance Frequency)放射体によるLED電球の放射冷却に関する研究(D3 モノづくり)

D33 SRF(Super Resonance Frequency)放射体によるLED電球の放射冷却に関する研究(D3 モノづくり)

406 LED電球の発熱における放射冷却効果について(応用熱工学II)

406 LED電球の発熱における放射冷却効果について(応用熱工学II)

415 オフィスを対象とした放射冷房システムの数値シミュレーション : 放射パネルの配置に関する検討(環境数値シミュレーションI,環境保全型エネルギー技術)

415 オフィスを対象とした放射冷房システムの数値シミュレーション : 放射パネルの配置に関する検討(環境数値シミュレーションI,環境保全型エネルギー技術)

A-9 ブラインドを持つ窓の日射熱負荷計算モデルに関する検討

A-9 ブラインドを持つ窓の日射熱負荷計算モデルに関する検討

Radiation Cooling Experiments and Reactor Application

The concept of a cold radiative plasma boundary is presented as a possible solution of the energy exhaust problem in a fusion reactor. The most relevant processes which determine level and location of the radiation from low-Z impurities are discussed in detail. Experimental results are used to demonstrate the general feasibility of generating a stable and quasi-stationary plasma with a cold radiating layer on a high power level. Furthermore, the limitations of the concept are briefly analyzed addressing feed-back control of the impurity level, thermal stability, particle transport and ignition conditions.

Radiation Cooling Experiments and Reactor Application

The concept of a cold radiative plasma boundary is presented as a possible solution of the energy exhaust problem in a fusion reactor. The most relevant processes which determine level and location of the radiation from low-Z impurities are discussed in detail. Experimental results are used to demonstrate the general feasibility of generating a stable and quasi-stationary plasma with a cold radiating layer on a high power level. Furthermore, the limitations of the concept are briefly analyzed addressing feed-back control of the impurity level, thermal stability, particle transport and ignition conditions.

Cyclotron Maser Cooling of Particle Beams and Quantum Field Action Effect on Radiation Cooling

A new particle beam cooling scheme “cyclotron maser cooling” (CMC) was examined. Under a stimulating rf field below the critical value prescribed by an action time of the field, a beam of gyrating electrons obeyed the Liouville's theorem. However, when the field reached the critical value, the beam abruptly jumped to a critical point of the radiative system undergoing CMC, where all electrons accumulated at one discrete energy within about 30 ns. On the other hand, when the field exceeded the critical value by less than 1 dB, a coherent energy modulation took place in gyrations. As a possible mechanism of this remarkable phenomena, a phase transition or a macroscopic quantum jump induced by the “quantum field action effect” on radiation cooling was presented. Under a stimulating ratiation field below the quantum field action any oscillator system remains non-radiative. However, under the stimulating quantum field action, a macroscopic quantum jump to the radiative system takes place leading to its cooling...

A Study of Cooling and Heating Utilizing Aquifer Thermal Energy Storage. Design of Radiation Cooling and Heating with Thermal Comfort.

With the use of aquifer thermal energy storage for heating and cooling, one of the main aims of this study was to establish a method for keeping energy consumption levels low while heating or cooling utilizing a large quantity of stored water. Therefore we have proposed continuous cooling and heating requirements whereby the difference between the ambient air temperature and the water temperature is minimized. This paper reports the subjective ratings of the room thermal sensations by a large number of Japanese subjects while the thermal condition was monitored. Radiation, thermal convection and evaporation were analyzed using a cylindrical model to approximate the human body. The results indicated that thermal comfort was obtained under the following conditions : (1) the ratio of the radiation heat transfer coefficient to that of convection was 2.34 for cooling and 2.19 for heating, and (2) the ratio of heat loss by evaporation to the sum of radiation and convection was 0.052 for cooling and 0.050 for heating. Finally, a new thermal design process based on thermal comfort was proposed.

Focusing of Intense Ion Beams by Radiation Cooling in a Magnetic Mirror

It is shown that a space-charge-neutralized intense ion beam can be focused down to diameters of \ensuremath{\sim}${10}^{\ensuremath{-}1}$ cm by injection into a magnetic mirror through the combined action of the magnetic field and nonadabatic radiative energy losses. These intense tightly focused beams may be important for the eventual ignition of thermonuclear microexplosions.

Radiation Cooling Effects on Interaction of a Shock-Heated Plasma Flow with a Transverse Magnetic Field

Radiation Cooling Effects on Interaction of a Shock-Heated Plasma Flow with a Transverse Magnetic Field

Radiation Cooling behind a Strong Shock in Krypton

Strong shocks at Mach numbers from 10 to 15 and at initial pressures between 1 and 10 Torr are produced in a conventional diaphragm shock tube. The effect of radiative energy loss from the plasma behind the shock is studied by quantitative measurement of the decay of continuous emission at λ = 4000 Å. It is shown that for high electron densities the maximum emissivity deviates remarkably from Unsöld's theory. The variation of flow parameters with increasing distance from the shock front is calculated using an iterative method developed by Pomerantz. The results indicate that the observed luminosity decay cannot be explained by losses of continuous radiation alone. The influence of resonance radiation and line emission on the plasma cooling rate is briefly discussed.

Radiation Cooling of Finite Heat-Conducting Solids

Radiation Cooling of Finite Heat-Conducting Solids

Radiation Cooling by Means of Cold Plates

Radiation Cooling by Means of Cold Plates

Radiation Cooling of Dairy Cattle

Radiation Cooling of Dairy Cattle