Heat exchanger from rinse tank to fresh tank?

[Johnny]

A lot of btu's sitting idle in my waste tank waiting to be pumped/dumped. Why not coils of recirculating fresh tank to waste tank to preheat fresh? Apo could be adjusted to drain off the top of the tank until shut-down. Or at least waste rinse make a trip through a coil in the fresh tank before being dumped?

This probably ins't a new idea, but I might try it on my rig.

 

[Shawn Forsythe]

Re: Heat exchanger from hot rinse return to fresh tank?

With an 80 gallon recovery tank, there are approximately 31,000 BTU's available. Presuming that the wastetank were perfectly insulated, and your exchanger was 100% efficient, you might break even on the capital expenditure after a few years.

There are much less expensive and efficient ways to obtain 31,000 BTU's.

 

[Johnny]

Thanks, Shawn, for saving me the effort.

 

[Greenie]

How on earth did you compute that?

If one guy runs a spit fire and another a vortex, the waste tanks woould vary wildly in temps and capacity.

 

[Bob Foster]

 

[Shawn Forsythe]

Regardless of temperature before the jet orifice, the "water" that makes contact with the fiber will have a temperature that cannot be exceeded, for it would not be water but live steam. As such, there is a maximum value that the waste water can achieve. Furthermore, cooling is always occurring. Actual recovery water temperature will range somewhere between 120-130 degrees Fahrenheit. The usable BTU content of that water is calculated using the difference between that temperature, and the temperature of the incoming supply water temp. Knowing that temperature differential and the weight of the water at capacity will give us the approximate theoretical BTU content of the wastewater. Knowing that figure, and also known is that it is practically impossible to capture and transfer all that heat energy with 100% efficiency, the paltry amount of that heat content is of lesser value than other means of heat generation and capture.

You are better off increasing the heat efficiency of those processes already in use on the unit to heat the water.