i have a water system. it consists of a boiler and a condenser when the water passed throught the condenser it gets hot by exchanging heat with the vapor coming out from the boiler...this hot flow (coming out of the condenser) is being wasted to the drain. instead of this i want to recycle the water to the condenser but it has to be cold enough. i don't want to use a heat exchanger because this will require an additional amount of water..and this is not preferable within my process...can u please help
It could be the actuator on the hot water valve. You normally have two motorised valves - one for the HW and one for the CH. Sometimes they are combined in a 3-port valve. To see if the actuator in the valve is working, you need to test for voltage at the orange wire from the valve. You can also hear or feel when the valve is opening. It is probably electrical though as the valve must open for HW to go through - it's just not telling the boiler to turn on. This is what the orange wire does. There's one on the CH valve too. Check the orange wire is properly connected. If it is, and you still have no voltage, the actuator could be broken. You can easily change the head of the valve without disturbing the plumbing at all and this should cure it.
some of these ideas are great but you could also consider how a chiller works. When a chiller wants to creat cold air it doesnt just circulate refridgerant through a coil, it expands the gas in the liquid at rapid intervals by enlarging the pipe in a short length. So if you want to chill the water just increase the pipes diameter over the length in short pieces. Should work for what you are attempting
You could use some kind of air-water heat exchanger. However it probably will be very big exchanger because the high surface required. I am not an expert in this matter but remember some years ago in my company we deal with a similar problem. The calculations lead to a very big air-water exchanger
We are using a truck radiator, an axial flow fan(1/3 hp), a 300 liter buffer tank, a 1/2 hp hot water centrifugal pump, and an old British Railways non-rusting formulation for the coolant for a similar purpose for a 24 KW water distilling plant. This has been working for years without any breakdown. We have since been duplicating this wherever needed. Incidentally the water for condenser cooling need not be very cold. Our inlet temperature is about 60 deg C and the out let about 75 to 80.
The main methods of achieving temperature change in any working fluid are with heat exchangers or with a phase change. The point Mac is making is that a heat exchanger does not have to have a separate water source, it can be a simple radiator. The radiator in your car is a heat exchanger that uses forced convection to facilitate heat transfer and it can be very effective. You can buy radiators off the shelf that are designed for either natural convection or forced convection (with a fan or some other source of moving air). From a refrigeration standpoint, a phase change is often a cleaner, more effective way to cool down a working fluid. This can be done with an expansion valve or any similar nozzle that reduces the pressure in your system. This also takes a little bit more work on the calculation end of things, because you will need to know and work with the thermodynamic properties of water in order to figure out the sizing of the components. However, it sounds like you have a reasonable grasp of thermodynamics, so that might be a good approach. If it were me, I would visit the junkyard and pick the radiator out of a car. Hope that helps.
