Tube-in-Shell Heat Exchangers

Tube-in-Shell Heat Exchanger

Cutaway of a tube-in-shell Heat Exchanger

Tube-in-shell (Tube) heat exchangers are constructed entirely from 316 L marine grade stainless steel to offer extreme durability and protection from corrosion.  The compact design of these units allows for more surface area to be packed in a shorter length, making them an ideal candidate for natural convection sidearm designs.  Heat transfer is enhanced through low profile grooves rolled into the tubes that creates moderate turbulence on the potable water side without the problematic mineral deposition often found in finned units.  Tube heat exchangers are available in two sizes: the smaller ST-3.6 is ideal for residential systems with up to 64 sq. ft. of collector area, and the larger ST-4.7 is well suited for larger systems and small hydronic heating applications.

SunEarth Model Number	Diameter (in)	Length (in)	Surface Area (sq ft)	Tubeside Volume (gal)	Shellside Volume (gal)	Dry Weight (lbs)	Max Pressure (psig)	Tubeside Connection	Shellside Connection
ST-3.6	3 1/8	15 7/8	2.64	0.080	0.244	6.2	250	3/4" NPTF	1-1/2" NPTF
ST-4.7	5 5/8	15 1/4	4.70	0.224	0.340	7.2	250	1" NPTF	1-1/2" NPTF

Typical Applications
 Tube heat exchangers are typically used as a sidearm style heat exchanger in retrofit applications, or where cost and availability of indirect fired water heaters such as the Ruud HE tank are a concern.  In such situations, the tube heat exchangers allow for any conventional electric water heater to be converted to use with solar.  If the tank is to be used as a pre-heater for a gas fired unit then it is suggested that the elements be removed from the electric water heater and the tube heat exchanger plumbed between the element holes for optimal performance.  If the water heater is to used as the auxiliary heater, then the tube heat exchanger may be plumbed between the drain and a tee placed on the hot water outlet leaving the elements intact.  In either scenario, a second pump may be placed in the potable water line for increased performance. 

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