Specification

1-150.15
6
DESIGN BENEFITS
Unit Features - Low Water Temperature Greenhouse Heating Units
The Modine model GLW units are specifically designed to heat greenhouses
with low-temperature water. They can be successfully used in applications
where waste or reject heat from steam-electric power plants, refineries,
pumping stations, distilleries, and other industrial or processing plants can
be utilized for heating. With the ever-increasing cost of fossil fuel, utilizing
reject heat as a heat source for greenhouses is a sensible solution with the
model GLW.
Standard features include:
• Hot water coil with 1/2" O.D. copper tubes, aluminum fins, and 1-1/2" MPT
copper connections.
• Maximum operating pressure is 300 PSI, maximum operating water
temperature is 180°F
• Frame, enclosure panels, and 24" polytube transitions are galvanized steel
for corrosion resistance in humid environments.
• 1/2 HP, totally enclosed motors (1 for GLW330S, 2 for GLW660S), available for single phase or three phase voltages.
• High airflow, 3850CFM for GLW330S and 7700CFM for GLW660S, based on 150 feet of polytube duct.
Unit Sizing
Unit performance is based on the flow rate and the temperature of
the water relative to the ambient air temperature. Refer to Figure 6.1
and the following example for determining performance.
Example:
Determine heating capacity in BTU/hr for model GLW660S at
20GPM, 100°F entering water, and 70°F entering air.
1. Figure 6.1 shows output in terms of BTU/hr per °F of ETD
(Entering Temperature Difference). ETD is the difference between
the entering water temperature and the entering air temperature.
For this example, ETD = 100°F – 70°F = 30°F.
2. From Figure 6.1, at 20GPM, the BTU/hr per °F of ETD for the
GLW660S is 5000.
3. The heating capacity = 5000 x 30 = 150,000 BTU/hr.
4. The water temperature drop = (heating capacity)/(500 x GPM) =
150,000/(500 x 20) = 15°F.
5. The water pressure drop from the curve is 0.7 Ft. of water.
Dimensions and Specifications - Model GLW660S, GLW330S (All dimensions in inches)
Figure 6.2 - Top View Figure 6.3 - Discharge and Side Views
Weight: GLW330S=200 lbs., GLW660S=380 lbs.
GLW330S
GLW660S
23.88" O.D.
15.75" 31.0"
23.88" O.D.
62.5" - GLW660S
32.5" - GLW330S
8.0"
MAX
31.5"
14.0"
19.0"
38.0"
10.0"
Note: Information on this page applies only to Model GLW units. Information contained in Catalog that is not on this page does not apply to Model GLW units.
6000
5000
4000
3000
2000
1000
10
Water flow rate
gallons per minute
Water pressure drop
ft. of water
Heating capacity
BTU/HR/ F of ETD
20 30 40 50
1.0
2.0
3.0
4.0
Model GLW660S
Model GLW330S
GLW330
GLW660
Figure 6.1 - Model GLW Performance Curves