Plate Heat Exchanger in Open Storage Tank?

[WoodChoppa]

Anybody used a flat plate heat exchanger instead of coil loops in a storage tank? I searched the archives high and low but could not locate the thread I thought I read about the plate heat exchanger dropped into an open storage tank. I'd appreciate assistance in locating that thread or anyone's experience with that setup.

Thanks!

 

[jebatty]

I used one in the past, then switched to pressurized storage. These are not "dropped into an open storage tank." They are plumbed counterflow, Side A to and from boiler, and Side B to and from storage tank (or other use). Normal design specs result in about a 10F temp drop from Side A to Side B at a delta-T of 20. Example: Side A in at 180, out at 160; Side B in at 150, out at 170; but all of this is system and use dependent. IMO close attention needs to be given to required btu transfer, flow rate and pressure drop both sides, and sizing the circulators and plumbing accordingly. If the intent is heating DHW or other potable water use, then safety would require a double wall exchanger.

Right now I use a flat plate HX between my pressurized storage and radiant floor, the reason being the need to separate the two sides because the floor uses an antifreeze mix and the storage is water.

Good info is available from FlatPlate.

 

[bigburner]

plate hx have been used "dropped "in chiller barrels since they came out. exact same process - Just cooling.

some places require double wall HX. We aren't required here if the transfer fluids are no toxic. Water is considered non toxic even if it has additives - but on a common sense note we always run the hyd system at a lower pressure. In event of a leak the Hyd system will be over pressurize and dump water on the floor threw the blow off.

 

[mwk1000]

I use a flat plate to heat my DIY storage. Not in the tank , need to be able to repair/maintain/replace so I kept it outside the tank. EKO 60 w/glycol on one side, water on the tank side. 70 plate unit.

 

[WoodChoppa]

Thanks for the replies. I wouldn't be using the water in the tanks or in the loops for consumption, probably throw on a sidearm or add another plate for DHW.

mwk1000 Please excuse my confusion but if you don't have the plate exchanger in the tank how are you transferring the heat to the water in the tank? Through a coil?