During cooking in the cafe kitchen, a lot of heat in the form of vapor is lost through the exhaust hood into the outside air. It is estimated that this hood is turned on, 60% of the time (6.5 hours out of 11 ).  If the outside temperature averages 11 °C over the year, and a residual heat of about 27 °C is released inside during cooking, it is estimated that about 10.8 kW per cooking time is lost through the stove. Over a year, this comes down to a heat loss of 25.661 kWh. 
Similair to the reuse of energy from the battery system, energy in the form of heat from the stove can be reused. This time by means of a cross-flow heat exchanger, it ensures that the air conditioning system needs to add less heat, through a heat pump and ventilation system, to the kitchen or any of the other rooms of the fort*. This heat exchanger can recover about 80% of the heat loss.  When this cross-flow heat exchanger is applied, 15,397 kWh can be recovered annually and 10,264 kWh will still be lost. 
 
* Assumed that in the future the fort will use a low-temperature heat pump and central ventilation system to meet its comfort needs.