Actually there are four reports of LENR endothermic reactions, including Arata and Ahern
http://newenergytimes.com/v2/library/2012/2012EPRI-1025575-Ahern.pdf Probably more examples were seen and written off as calibration error, since endotherm is so unexpected. From: Jed Rothwell ChemE Stewart wrote: Unless part of the "reaction" is endothermic and cools its surroundings... I do not think anyone has ever detected an endothermic cold fusion reaction. You could detect that with a calorimeter as easily as you can detect an exothermic reaction of the same magnitude. - Jed
