Method for Producing a Latent Heat Storage Material and Dialkyl Ether as a Latent Heat Storage Material

Abstract

The invention relates to a method for producing latent heat storage material from linear alcohols by dehydrating to dialkyl ethers or to olefins, and hydrating to paraffins and dialkyl ether as a latent heat storage material.

Description

FIELD OF THE INVENTION[0001]The invention relates to a method for producing a latent heat storage material from linear alcohols and dialkyl ether as a latent heat storage material.BACKGROUND OF THE INVENTION[0002]Phase change materials (PCMs) may release or absorb, respectively, or store, respectively, heat by melting or solidifying, respectively, within a defined temperature range, and thus function as latent heat storage materials. This principle of heat storage may also be used, for example, in the wall insulation of buildings. Such latent heat storage materials are, e.g. in the form of micro-capsules, introduced into the wall plaster or into gypsum plasterboards and liquefy during the day with high heat input. The heat absorbed is stored in the wall and keeps the interior cool. Following cooling during the evening hours and at night, the liquid storages solidify and release the crystallization heat to the environment. In that, the interior is warmed up.[0003]As latent heat stora...

AI Technical Summary

Benefits of technology

[0006]The object of the present invention therefore is the provision of highly linear compounds, like paraffins, with a defined chain length for use as latent heat storage materials. Herewith, the following advantages are achieved: on the one hand, the melting range of highly pure paraffins is clearly narrower compared to paraffin mixtures, and thus the full storage capacity can be used at low temperature differences already. On the other hand, the melting enthalpy of the pure substance is clearly higher than that of the mixtures.

[0019]It was thus surprisingly found that particularly paraffins are suited as linear paraffins for PCM applications, which can be produced by dehydrating linear alcohols to linear olefins and their subsequent hydration. The linear alcohols used are easily available as single sections and are preferably based on renewable vegetable or animal raw materials, in particular vegetable ones, like e.g. palm oil, palm kernel oil, coconut oil, rapeseed oil or other vegetable oils.

[0024]For this special application, the prices of the paraffins are higher than the prices of fatty alcohols. The required quantities of latent heat storage used directly correlate with the melting heat used, i.e. that substances which have a 20% higher melting heat, also accordingly have to be used in lesser quantities in order to achieve the same effect. For example, textiles can be produced with the same storage capacity with a lesser weight, and thus the wearing comfort can be clearly increased.

[0026]In the comparison of products produced by means of dehydrating fatty alcohol, dialkyl ethers and olefins / paraffins, the dialkyl ethers have the advantage that they can be produced economically, since for every 2 mol of fatty alcohol, only 1 mol of water has to be eliminated. As far as desired, the ethers may be stabilized against peroxide formation by means of antioxidants, wherein it is assumed, that in the micro- or macro-capsules, in which PCMs are frequently used, a decomposition of the ethers is sufficiently minimized by the capsule layer (frequently a polymer layer).

Problems solved by technology

90 to less than 95% by mass in the C16 to C18 range, and have the disadvantage that due to the branched side products, their melting enthalpy is clearly lower in comparison to that of highly linear paraffins.

It was found, that mixtures of even-numbered and odd-numbered paraffins, such with different chain lengths and / or higher branched portions have the disadvantage that these have wide or several different melting peaks, wherein, when these peaks are too far apart with regard to the temperature, normally only part of the possible melting enthalpy can actually be used.

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