Heat energy vs. electrical energy in a galvanic cell or in an electrochemical reaction How can someone determine heat energy released during an electrochemical reaction?

Let's assume a simple galvanic cell at standard environment:  

$$\ce{Zn(s) -&gt; Zn^2+(aq) || Cu^2+(aq) -&gt; Cu(s)}$$

Electrical energy can be derived from the electrode potential and electron flow, but how the heat release can be calculated? What's the heat release when $\ce{Zn(s)}$ gets solvated to $\ce{ZnSO4(aq)}$, and whats the heat release when $\ce{Cu^2+}$ ions gets plated to the electrode?

I'm using term "heat release", because I get confused about the enthalpy in electrochemical cells, since some of enthalpy seems to be connected to electrical work as well.
Operational electrochemical cells have $\Delta G\lt0$
And,
$$\Delta G=-nFE$$
$$\Delta G=\Delta H-T\,\Delta S$$
Knowing the entropy change, enthalpy change could be calculated
or
$$\Delta H=-nFE+nFT\frac{\mathrm d\Delta G}{\mathrm dT}\quad\text{at contant }p$$