flat plate exchangers

91winsun
91winsun Registered Users Posts: 14
http://www.pexsupply.com/FlatPlate-FP3X8-14-14-plate-3-4-Thread-8-GPM-Heat-Exchanger-3-x-8-5776000-p

what is the inside design in these??? do the pipes go all the way thru and out and the plates just get hot like a car radiator without getting wet??

Comments

  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: flat plate exchangers

    There is a flat plate dividing the container into two chambers. The hot water supply is passed through one side of the chamber, giving up heat to the flat dividing plate, which then heats the separate water supply on the other side of the flat plate. The two waters never come in contact with each other, and the heat is transferred through the flat plate.
    More complex and higher efficient models may have several flat plates, creating several chambers, but the basic principal is the same, just that there is a greater surface area through which to transfer the heat. The one in you're link actually has 14 plates, and there is a drawing of one opened up and partly pulled apart here: http://s3.pexsupply.com/manuals/1297373935403/47228_PROD_FILE.pdf
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: flat plate exchangers
    91winsun wrote: »
    http://www.pexsupply.com/FlatPlate-FP3X8-14-14-plate-3-4-Thread-8-GPM-Heat-Exchanger-3-x-8-5776000-p

    what is the inside design in these??? do the pipes go all the way thru and out and the plates just get hot like a car radiator without getting wet??

    In this design, there are two sets of pipes and the temperature of the outside of the unit does not matter much. Inside it two different fluid circuits are both connected thermally to each other but do not have any liquid interconnection. One way this could be done would be to braze the two sets of pipes in a dense zig-zag to opposite sides of a flat plate.
    Another way to to it would be to put fins on one length of tubing and have the fluid from the other set of pipes circulate around it.
    In your radiator, the heat is transferred from the coolant tubes to fins in the air. If you put water through the radiator from front to back instead of air, you would have fluid to fluid heat exchanger like the one is the add. Just built differently.
    SMA SB 3000, old BP panels.
  • CDN_VT
    CDN_VT Solar Expert Posts: 492 ✭✭✭
    Re: flat plate exchangers
    91winsun wrote: »
    http://www.pexsupply.com/FlatPlate-FP3X8-14-14-plate-3-4-Thread-8-GPM-Heat-Exchanger-3-x-8-5776000-p

    what is the inside design in these??? do the pipes go all the way thru and out and the plates just get hot like a car radiator without getting wet??

    What are your questions to help with ?
    Solar collection etc.


    Stainless is a "buzz" word , Like Pentium (remember them ) I-poo and all the rest marketers speeal ..,,,, It really depends on chemicals & temp.
    Potable or not , type of stainless for the chemical's used. Mine are kept at close pressures . less distortion while also having a potable water settling tank to help with oxygen in the DHW side.

    Many things to consider. Plus what I C&P below.
    Heat Exchanger Sizing

    Needed Parameters:

    Type of both fluids (water, % antifreeze mix with type of glycol used, etc..)

    Flow rate of both fluids

    Inlet temperature of both fluids

    Max pressure drop for both fluids (default is 7 psi if not provided)

    1 of 3 Needed Parameters

    Outlet temperature of hot fluid

    Outlet temperature of cold fluid

    Heat transfer desired (Btu/hour)
    The more length the heat exchanger has, the more efficiency in heat transfer it has. An infinitely long heat exchanger would allow for the hot fluid to become the temperature of the cold fluid and the cold fluid the hot fluid, assuming perfect energy balance.

    The more plates and more width the heat exchanger has, the less pressure loss to the fluids flowing through. While adding more plates and width may increase some heat transfer, it is best to add more length for optimal heat transfer gain. More plates and width should be considered when flow rates reach half or more the max flow rate for the particular unit to avoid pressure loss in the fluid flow. Pressure loss means a slower flowing liquid and therefore, less heat transfer overall. In designs, we typically allow up to a 7.5 psi pressure drop, which is generally accepted as non-interfering with flow rates in a heat transfer application. Most low flow applications experience less than 1 psi drop.


    VT