Radiative cooler

A method and radiative cooling device for use in passively cooling spaces is described. It is applicable to any level of thermal radiation in vacuum and to high-intensity thermal radiation in non-vacuum environments. The device includes an enclosure nested in a multiplicity of thin, low-emittance, highly-reflective shields. The shields are suspended in a casing in mutual angular relation and having V-shaped spaces defined therebetween for redirecting, by reflection, toward the large openings of the V-shaped spaces, thermal radiation entering the sides of the shields, and emitted to the spaces, whereby successively reduced quantities of thermal radiation are reflected by the surfaces along substantially parallel paths extended through the V-shaped spaces to a common heat sink such as the cold thermal background of space

Flexible thermal apparatus for mounting of thermoelectric cooler

A flexible heat transfer apparatus used to flexibly connect and thermally couple a thermoelectric cooler to an object to be cooled is disclosed. The flexible heat transfer apparatus consists of a pair of flexible corrugated sheets made from high thermal conductivity materials such as copper, aluminum, gold, or silver. The ridges of the corrugated sheets are oriented perpendicular to one another and bonded sandwich-fashion between three plates to define an upper section and a lower section. The upper section provides X flexure, the lower section provides Y flexure, and both sections together provide Z flexure

Multicomponent gas sorption Joule-Thomson refrigeration

The present invention relates to a cryogenic Joule-Thomson refrigeration capable of pumping multicomponent gases with a single stage sorption compressor system. Alternative methods of pumping a multicomponent gas with a single stage compressor are disclosed. In a first embodiment, the sorbent geometry is such that a void is defined near the output of the sorption compressor. When the sorbent is cooled, the sorbent primarily adsorbs the higher boiling point gas such that the lower boiling point gas passes through the sorbent to occupy the void. When the sorbent is heated, the higher boiling point gas is desorbed at high temperature and pressure and thereafter propels the lower boiling point gas out of the sorption compressor. A mixing chamber is provided to remix the constituent gases prior to expansion of the gas through a Joule-Thomson valve. Other methods of pumping a multicomponent gas are disclosed. For example, where the sorbent is porous and the low boiling point gas does not adsorb very well, the pores of the sorbent will act as a void space for the lower boiling point gas. Alternatively, a mixed sorbent may be used where a first sorbent component physically adsorbs the high boiling point gas and where the second sorbent component chemically absorbs the low boiling point gas

The impact of temperature changes on residential energy consumption

To investigate the link between rising global temperature and global energy use, we estimate an energy demand model that is driven by temperature changes, prices and income. The estimation is based on an unbalanced panel of 157 countries over three decades. We limit the analysis to the residential sector and distinguish four different fuel types (oil, natural gas, coal and electricity). Compared to previous papers, we have a better geographical coverage and consider non-linearities in the impact of temperature on energy demand as well as temperature-income interactions. We find that oil, gas and electricity use are driven by a non-linear heating effect: Energy use not only decreases with rising temperatures due to a reduced demand for energy for heating purposes, but the speed of that decrease declines with rising temperature levels. Furthermore we find evidence that the temperature elasticity of energy use is affected by the level of temperature as well as the level of income

Cryogenic regenerator including sarancarbon heat conduction matrix

A saran carbon matrix is employed to conduct heat through the heat storing volume of a cryogenic regenerator. When helium is adsorbed into the saran carbon matrix, the combination exhibits a volumetric specific heat much higher than previously used lead balls. A helium adsorbed saran regenerator should allow much lower refrigerator temperatures than those practically obtainable with lead based regenerators for regenerator type refrigeration systems

Obstacles to the Revival of Mobile Grazing Systems in Kazakhstan

Livestock mobility was an essential characteristic of Kazakh livestock production systems, allowing animals to take advantage of spatial and temporal variability in climate and vegetation, optimising forage intake over the year. These systems broke down following the end of the Soviet Union. In this paper we examine the extent and determinants of the recovery of mobile livestock husbandry in south-eastern Kazakhstan, using surveys and semi-structured interviews with livestock farmers and rural households (holding livestock but not registered as farms). We find positive relationships between livestock holding size and probability of mobility. Winter pastures are particularly important for large farms, with households and smaller farms more dependent on supplementary fodder. The major formal property right over pasture is the long-term leasehold, allocated by auction and associated with significant transaction costs. Leasehold markets function poorly, so farms use a combination of leasing, subleasing and short-term contracts with local authorities to assemble the pastoral resources they need. Few farmers conduct more than a simplified summer-winter migration, whilst around 30% of farms and 70% of households (which own the bulk of livestock) are entirely sedentary, staying on over-used village pastures all year round. Many of these producers express a desire for improved pasture access. The 2017 Law on Pastures introduced district-level pasture use planning, with promotion of mobility and allocation of remote pastures to those with poor access. But the Law does not include new land tenure mechanisms appropriate for small producers (owning few livestock and without leaseholds) which can be employed to realise this goal. Moreover, most pastures are already leased. We discuss options for grazing system management which may simultaneously increase the economic contribution of pastures, improve their condition and reduce rural inequalities created by disparities in access to resources

Learning grasp affordance reasoning through semantic relations

Reasoning about object affordances allows an autonomous agent to perform generalised manipulation tasks among object instances. While current approaches to grasp affordance estimation are effective, they are limited to a single hypothesis. We present an approach for detection and extraction of multiple grasp affordances on an object via visual input. We define semantics as a combination of multiple attributes, which yields benefits in terms of generalisation for grasp affordance prediction. We use Markov Logic Networks to build a knowledge base graph representation to obtain a probability distribution of grasp affordances for an object. To harvest the knowledge base, we collect and make available a novel dataset that relates different semantic attributes. We achieve reliable mappings of the predicted grasp affordances on the object by learning prototypical grasping patches from several examples. We show our method's generalisation capabilities on grasp affordance prediction for novel instances and compare with similar methods in the literature. Moreover, using a robotic platform, on simulated and real scenarios, we evaluate the success of the grasping task when conditioned on the grasp affordance prediction.Comment: Accepted in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 201

The effect of the number of wavebands used in spectral radiation heat transfer calculations

A spectral radiation heat transfer model that conserves emitted and absorbed energy has been developed and used to model the combustion space of an industrial glass furnace. This comprehensive radiation heat transfer model coupled with a computational fluid dynamics (CFD) code was used to investigate the effect of spectral dependencies on the computed results. The results of this work clearly indicate the need for a spectral approach as opposed to a gray body approach since the gray body approach (one waveband) severely underestimates the energy emitted via radiation