MDSC Heat Flux melting and agglomeration of microcapsules of PCM

Hi there!

I'm here again because of my MDSC test with PCM. My heat flux curve is always in all samples negative. It is always under the cooling curve. I looked for a justification but I didn't find. Can somebody tell me why and if it's possible an article or something?

Another doubt I have, my teacher talked about agglomeration of microcapsules of PCM for an low enthalpy. but I didn't understand what is the effect of this, the justification. Can somebody help me?

Thank you in advance!