Abstract: A counter flow heat exchanger comprising a body formed of stacked, fused, ceramic sheets. The sheets comprising: a bottom sheet, a second sheet, a third sheet, a fourth sheet and a top sheet. The sheets have punched holes such that when the sheets are aligned there is an inlet hole spanning from the top sheet to the fourth sheet, an outlet hole spanning from the top sheet to the second sheet, and an inflow hole spanning from the fourth sheet to the second sheet. Within the second sheet, a low pressure flow channel connects the outlet hole with the inflow hole. Within the fourth sheet, the inlet hole flows into a high pressure flow channel which flows into a narrow flow path which then empties into the inflow hole. The high pressure flow channel is aligned with the low pressure flow channel to allow for heat exchange.