dissipate vs heap up

dissipate

verb
  • To use up or waste; squander. 

  • To drive away, disperse. 

  • To vanish by dispersion. 

  • To cause energy to be lost through its conversion to heat. 

heap up

verb
  • To make an untidy pile of (something). 

  • To increase over a period of time; to accumulate. 

How often have the words dissipate and heap up occurred in a corpus of books? (source: Google Ngram Viewer )