Solar Plate Heat Exchanger


Northern Lights Solar Solutions Plate Heat Exchangers. Our Brazed Plate heat exchanger consists of either 25 or 50 multiple, thin, slightly-separated corrugated plates that together form a very large relative surface area given the volume of these heat exchangers. They produce relatively low pressure drops and operate efficienly at the lower flow rates associates with solar and hydronic circulation systems. The stacked-plate arrangement can be more effective, in a given space, than most other type of heat exchangers. These Solar Brazed Plate Exchangers have a specially patented "wafer or corrugated " stamps that increase the flow turbulence and consequently the heat transfer and scaling factor making them ideal in solar application which have smaller flow rates.

Our line of brazed plate heat exchangers are single wall stainless steel versions. Some codes require double water heat exchangers with visible leak detection for potable domestic water where a double wall heat exchanger is required. We have two sizes; a 25 plate and a 50 plate version. The smaller 25 plate unit is suitable for up to 8 solar collectors and the larger 50 plate unit is used when the solar collectors exceeds 8 such as commercial solar heating or in applications were a low differential temperature gradient is needed.

The entire construction is sealed together by the means of brazing in a special vacuum furnace.



  • Central Heating
  • Heating and Cooling in HVAC installations
  • Hydraulic and Lube Oil Coolers
  • Tap Water and Radiator Heating
  • Hydronic Heating
  • Geothermal and Solar Heating
  • Evaporation and Condensation in Refrigeration Systems
  • Heat Recovery
  • Team Heating
  • District or Zone Heating Systems

The Outstanding Features:

  • Compact structure and easy installation
  • Light in weight
  • Small consumption of water
  • Outstanding Overall Heat Transfer Coefficient
  • Wide Variety of plate sizes and Patterns
  • Durability and
  • Stainless Steel
  • Low scaling coefficient


Overall Dimensions

(Dx B x A)


 SL15-25     3.15 x 7.5 x 2.6"

 SL15-50     3.15 x 7.5 x 4.85"

C=1.57" ; E=6.06"

Port Connections 316L

3/4” male NPT - load side (left D3 & D4)

1/2" male NPT -solar side (right D1 & D2)

Max Design Pressure

650 PSI

Design Temperature

225 °C  or 437 °F

Plate Material

316 L Stainless Steel

Brazing Material


Heat Transfer Rating SL15-25 = 150 kBTU/hr (44 kW)  
SL15-50 = 300 kBTU/hr (88 kW)
Design Delta T for Rated BTU 60 °K  or 108 °R
Heat Transfer Area SL15-25 =0.322 m2 (3.5 ft2)
SL15-50 = 0.672 m2 (7.2 ft2)
Pressure Drop (both sides with water) SL15-25 8psi @15USGPM
Liquid Retension SL15-25 = 0.23 L (.06 USGal)
SL15-50 = 0.48L (.13 USGAL)

NLSS Model: BL15-25K

NLSS Model: BL15-50K