Hot Water & Glycol Heating

Tell us the concentration actually in the loop, measured with a refractometer, plus the freeze point you need to protect against. Loops often run richer than required because someone topped up with straight glycol, and that extra concentration costs heat transfer. If the two differ we can size against either, and we will point out what the correction is worth.

Give us the lowest loop temperture at startup alongside the normal operating point. We check the flow regime at that cold condition, and if the channels go laminar we adjust plate pattern or pass arrangement so the coefficient holds. A unit checked only at operating temperature can take hours to bring a cold glycol loop up.

On a small, clean, well-treated closed loop it often is, and it saves space and cost. It cannot be opened, so it suits loops where fouling is unlikely and replacement is easier than cleaning. On a large loop, or one with a poor treatment history, the gasketed frame is worth its higher first cost.

EPDM is the common choice for hot water and glycol, since it handles both well accross normal loop temperatures. Nitrile becomes the weaker option as temperatures rise. Check that the inhibitor package contains nothing the compound dislikes, and tell us the peak supply temperature, because that is what decides gasket life.

More than the water loop did, because glycol carries less heat per gallon for each degree of temperature change. To move the same load at the same temperature drop, flow has to rise, and pressure drop rises faster still because the fluid is thicker. Check the pump curve before converting a loop, since the exchanger is often not the only part left short.