Aqua-Vent AVR Series | Dry Coolers Inc.

Dry Coolers Inc.

Industrial Process Cooling Systems

Dry Coolers, Inc.
575 South Glaspie Street
Oxford, MI 48371 USA

1-800-525-8173

Aqua-Vent AVR Series

Brochure Code
AVR-0205

Dry Coolerʼs AVR series fluid coolers are designed to provide the optimum in heat transfer efficiency and are constructed foryears of reliable performance. Available in 28 sizes for flows from 2 to 700 GPM. Only the highest grades of commerciallyavailable aluminum, copper and galvanized steel go into the manufacture of each AVR air cooled heat exchanger. After assembly every unit is closely inspected before it is securely crated to ensure trouble free installation and operation.

Aqua-Vent

Features

FAN / MOTOR

  • All fans are sized for maximum energy efficiency, minimum noise, and are individually balanced to minimize vibration.
  • All models have die stamped aluminum blades riveted to agalvanized steel spider assembly.
  • Fan guards are fabricated from heavy gauge steel wire andepoxy coated.
  • On multiple fan units, all fans are baffled to prevent short circuiting of air during fan cycling.
  • All AVR motor assemblies are supported in all-welded,heavy gauge wire support structures. The wire structures are zinc-chromate coated for corrosion protection.

Motors are available in the following voltages:AVR 5 thru 19 - 208/230/1/60, psc. Optional 460/1/60,230/3/60 or 460/3/60AVR 22 thru 108 - 208/230/460/3/60, open drip-proof.

COILS

  • Coil fins are manufactured from die formed corrugated aluminum. The tubes are seamless 1/2” OD copper, arranged in a staggered pattern and mechanically expanded into the fins and tube sheets for optimum heat transfer efficiency.
  • Headers are constructed from heavy wall copper tubing, and are brazed to the coil using a high temperature brazing process.
  • All coils are leak tested in an illuminated test tank at a pressure of 380 psig.

OPTIONS

  • Fan cycling control - available with individual contactors and either ambient or fluid temperature sensors.
  • Motor fusing - available on all models. Motors can be fused individually or in pairs (not U.L. listed).
  • Fins - available in four options; aluminum, copper, polyester coated aluminum, and baked phenolic coated aluminum.
  • Hinged venturi panel(s) - can be provided on all AVR models to allow for easy coil cleaning of the coil fins and quick access to the fan/motor assembly.
  • Horizontal air discharge - available upon request for allAVR models. Contact Dry Coolers for details.
  • Surge tank
  • Fill valve assembly

Nomenclature

AVR - 72 - 37
Design Series - Unit Size - Circuiting

Formulas


Eq. (1) Average Fluid Temp. = (Ent Fluid Temp + Lvg Fluid Temp) / 2
Eq. (2) Design Load (Btu/hr) = 500 x GPM x (SpHt x SpGr) x (Ent Fluid Temp - Lvg Fluid Temp)
Eq. (3) TD = Entering Fluid Temp - Entering Air Temp
Eq. (4) Base Capacity (MBh/°F) = Design Load (Btu/hr) .
1000 x TD x Cap. Corr. Factor x Alt. Corr. Factor
Eq. (5) Actual Capacity = Catalog Cap. x 1000 x TD x Cap. Corr. Factor x Alt. Corr. Factor
Eq. (6) Actual Pressure Drop = Catalog Pressure Drop x Pressure Drop Corr. Factor

Example Selection

Given:
Altitude 5000 ft
Ambient Temperature 100°F 
Entering Fluid Temperature 140°F 
Leaving Fluid Temperature 120°F 
Flow Rate 80 GPM
Ethylene Glycol Solution 30% 
Maximum Fluid Pressure Drop 15 ft wg.
1 Calculate the average fluid temperature using equation #1.
  • Average Fluid Temp. = (140°F + 120°F)/2
  • Average Fluid Temp. = 130°F

2 Calculate the design load using equation #2.

  • Design Load (BTU/hr) = 500 x 80 x .940 x (140°F - 120°F)
  • Design Load (BTU/hr) = 752,000 BTU/hr 

3 Calculate the fluid temp difference (TD) using equation #3.

  • TD = 140°F - 100°F
  • TD = 40°F

4 Determine the capacity correction factor from table 2.

  • Capacity correction factor = 1.027 

5 Determine the altitude correction factor from table 5. 

  • Altitude correction factor = .89

6 Calculate the base capacity using equation #4.

  • Base capacity (MBh/°F) = 752,000 / 1000 x 40 x 1.027 x .89 
  • Base capacity (MBh/°F) = 20.57 
7 Using the performance tables number 6, select a model thatmeets or exceeds the required base capacity at the required fluidflow rate. Model AVR-62 with 30 circuits will meet the capacityand maximum pressure drop requirements.
8 Correct the fluid pressure drop using equation #6.
  • Actual Pressure Drop = 13.6 x .963
  • Actual Pressure Drop = 13.1 ft w.g. 
9 Calculate the actual unit rating using equation #5.
  • Actual Capacity = 21.54 x 1000 x 40 x 1.027 x .89
  • Actual Capacity = 787,528 BTU/hr
10 Select the header connection size from table 8. 2-1/2" headerswith the same size MPT connections will be required.