There is problem fixed in the recuperator led to decrease the water temperature, the supervisor asked you to replace it by a new one, the choices are: a) Counter flow recuperator: is one of heat exchanger in which the direction of the flow of one of the working fluids is opposite to the direction to the flow of the other fluid shown in figure "2". b) Tc, in Th, out To, in Counter flow Th, out Figure "2" Th, in To.out To, out Parallel flow recuperator: is one of heat exchanger in which both fluids flow in the same direction shown in figure "3". Flow Direction Th, in Ton Parallel flow Thin Thout Figure "3" Th, out To, out