Something frigorific causes cold or is chilling. The chill here is from Latin frigus, cold, a root that’s also the source of refrigerate and frigid, as well as the obsolete frigor, a state of extreme coldness.
A search through a database of recent newspaper articles suggests strongly that the most common appearance of frigorific is in that characteristically American phenomenon, the spelling bee. This report in the Palm Beach Post on 24 February 2004 on the finals of a regional event is typical: “And for the next 45 rounds, McDowell and Duran took turns before the microphone, batting words away with scarcely a pause. They spelled superencipherment and aerolithology, gorgonize and subaqueous, eutrophic, alpaca and frigorific”.
It has never been common and the examples I’ve gleaned suggest that when it has appeared, it has been in some technical or scientific context. For instance, if you will turn to your copy of the Iowa City Press Citizen for 30 September 1925, you will read a report that the gaseous element helium had been liquefied for the first time (the report’s headline announced that it had been melted, which is a difficult feat, because helium is the one element that can never be frozen in the first place): “At the frigorific laboratory of the Charlottenburg Polytechnic a specialty is made of experimenting with and studying all matter and the changes produced when exposed to extremely low temperatures.”