 So the other regenerative ranking that we want to look at is the regenerative ranking with the closed feed water heater. So this is basically just a shell and tube heat exchanger and one thing about the closed feed water heater is it does not de-airate as we saw with the open feed water heater. So what we're going to do, we're going to begin by taking a look at the process schematic and then the TS diagram. So there we have the closed feed water heater regenerative rank and it's getting a little messy. But just like we did with the open feed water heater where we strip steam off and so what we're doing is we're taking steam off at a given mass fraction and we then take that and we don't mix it together but we send it through this device here which is our closed feed water heater and it's essentially like I said a shell and tube heat exchanger. We have the one fluid stream coming through and not mixing with the other one but they interact across an interface and consequently transfer thermal energy. So with that the steam that is being stripped off on our TS diagram is at state seven. It comes down to state three and in the process it's giving up thermal energy enabling the fluid at state two which is right here to move up to state nine. So the fluid moves up a little bit to state nine as a result of going through our feed water heater and the consequence of doing that, so we come out and we're at state nine but we're not at 100% mass fraction so we still have to go into a mixing chamber and that's where we take fluid from state four which is right here after our pump. We go from fluid at state four and we come out with fluid at state five so let me try to write a circle there. So that is what is then going back into our boiler. It's a little complex and convoluted especially as you get into the tightly packed part of the TS diagram there but again same sort of principle as before in terms of looking at mass fractions so what we will do is the next thing we'll do is we'll take a look at the equations that you would be using for the feed water heater if you have a closed feed water heater. So Q in like before it's H6 minus H5 so it's basically the change in enthalpy across the boiler. Q out now we need to be careful here because we don't have 100% of the mass flowing through the condensing unit and that's why we have 1 minus Y for the mass fraction. Turbine workout for the first part we have 100% of the flow and then we strip some of the steam off and we only have a reduced percentage and so we acknowledge that by having a two part equation there and the latter that should be H7 minus H8 and work pump in. So let's take a look at our schematic here. We have two pumps, pump there, pump there, pump one, pump two and we have different mass fractions 1 minus Y and Y going through both of them and that's why we have the two components in the equation there. And finally mass fraction just like before M.7 divided by M.6. So those are some of the equations that you have to apply when you're looking at the closed feed water heater. The next thing that we'll do we'll take a look at applying the first law to the closed feed water heater and see where that takes us.