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Energy Efficient Axial-Flow FRP Fans E-mail

The axial flow fans are widely used for providing the required airflow for heat & mass transfer operations in various industrial equipment and processes. The grey area today is the inconsistency in proper aerofoil selection & dimensional stability of the metallic impellers. This leads to high power consumption & high noise levels with lesser efficiency. Keeping in view the international trends and energy savings potential, the project on 'Development of Energy Efficient FRP Axial-flow Fans' was launched by the Mission in partnership with M/s. Parag Fans & Cooling Systems Ltd., Dewas (MP).

The project involves improvisation of fan design by the selection of the most appropriate aerodynamic blade shape to suit specific airflow applications, development of suitable composite materials and Structural design to replace the use of metals such as aluminium and mild steel in impeilers. FRP fans can thus replace the conventional metallic fans which have less efficient operation, high power consumption and shorter life span.

The technology support in terms of aerodynamic design of axial flow fan impellers, composite structural design and the fabrication process is being provided by the Department of Aerospace Engineering, Indian Institute of Technology (IIT, Mumbai).

The project has embarked on development of two sizes of fans to meet stringent duty Conditions and market demand:

  • 14 feet diameter fan : This finds applications in air heat exchangers for process industries. They are normally required to operate at lower RPM against low system pressure but with high discharge rate. Low noise level is a major criterion for the fan design. Currently these fans are being imported and hence, developing these fans would improve indigenous capability.
  • 32 feet diameter fan : This is typically suitable for large scale cooling towers for various industries such as power plants, refineries, petrochemicals, fertilizers etc. Large discharge rates at low RPM and against low system resistance are the primary characteristics of this type of fan. The fan should facilitate substantial energy savings.

The necessary raw materials for the fan impellers include glass fibre in various forms like chopped strand mat, rovings, woven rovings cloth surface mat and resin (epoxy & polyester) catalysts, accelerator, hardener, pigments, surface treatment agents etc. All the raw material are available indigenously.


The FRP fans have the following advantages:

  • Optimal aerodynamic design of fan impellers to provide higher efficiency for any specific application.
  • Reduction in overall weight of the fan, thereby extending the life of mechanical drive systems such as motors, gear boxes, bearings etc.
  • Requires lower drive motor rating and light duty bearing system.
  • Low power consumption resulting in appreciable energy savings as compared to existing metallic fans.
  • FRP fans produced by composite fabrication processes such as compression moulding/resin transfer moulding technique would have uniform dimensions and consistent quality of fan impellers.
  • Lower flow noise and mechanical noise levels compared to the conventional metallic fans.
  • Longer life of fans due to improved mechanical strength.
  • Excellent corrosion and erosion resistance.
  • Fire retardant.
  • Vibration-free operation.

As the fan efficiency is defined as (Q x D Pt)/ (Shaft horsepower), thus with reduced shaft power requirement, there is a commensurate reduction in energy consumption.

Under the project, the following five types of fans were identified for development for their bulk requirement in the country:

  • 1200 mm dia. fan for textile mill humidifiers against technical specifications provided by ATIRA, Ahmedabad.
  • 2000 mm dia. fan for mine ventilation against specs. of Western Coalfields Ltd. (WCL), Nagpur of Coal India Ltd.
  • 4267 mm (14 ft.) dia. fan for air heat exchangers against specs. of Engineers India Ltd., New Delhi.
  • 1680 mm dia. fan for radiator cooling for diesel locomotives as per the specs. provided by RDSO, Lucknow.
  • 10,000 mm. (34 ft.) dia. fan for cooling towers as per the specs. of M/s. Balcke Durr Technology India Ltd., a German MNC.

Apart from optimally designed impellers, an axial flow fan also comprises other critical components such as fan hub, support plates, fasteners, bushes for fixing the drive shaft etc. The FRP fan blades and the hub are assembled together & are again subjected to static & dynamic balance test and inspected at various stages as per the quality assurance plan. FRP fans provide substantial energy savings as compared to conventional aluminium and MS fans thereby reducing initial equipment & operational cost.

All the development activities encompassing designing the fans, selection of raw materials, stabilizing fabrication procedure & finally performance testing of four fans were completed by December 1999.

Five fans as mentioned above have been developed successfully under the project. The performance evaluation of all the five types of fans established an efficiency differential of around 25% over conventional fans with aluminium impellers. The air heat exchanger fan, fabricated by Resin Transfer Moulding (RTM) technique, tested at the refinery of Indian Oil Corporation (IOC) Ltd., Panipat with over 30% energy saving as compared to existing fans imported from overseas suppliers. RDSO fan has also been fabricated by RTM and tested as per ANSI/AMCA with improved performance.

FRP Fan Test Results Vs. Conventional Fans with Aluminium & Steel Impellers

Sl. No.

Type of FRP Fan

FRP Fan Efficiency as Certified by User Agencies

Efficiency Improvement over Conventional Fan

FRP Fan Energy Savings over Conventional Fan

1. Cooling Tower Fan




2. Textile Mill Humidifier Fan*




3. Mine Ventilation Fan




4. Radiator Cooling Fan* for Railway Diesel Locomotives

65.67% to 70.24%

2.33% to 9.62%

1.86% to 4.60%

5. Air-heat Exchanger Fan

74.01% to 80.04%

20.79% to 21.09%

28.96% to 34.93%

* Tested on the Test Rig as per ANSI/AMCA 210-85

It is estimated that around 2,500 fans of various sizes and applications can be replaced in a year with a growth rate of 15% per annum in the replacement market. It is also expected that around 1,500 fans of various sizes can be sold in the OEM market with a 10% p.a. growth rate. The axial flow fans enjoy good export potential, especially in the neighboring countries, as there are very few manufacturers of FRP fans, which mostly located in Europe and the U.S.A.

PARAG Fans & Cooling Systems Limited
Plot no. 1/2B & 1B/3A,
Industrial Area no. 1, A.B. Road,
Dewas - 455 001 (MP), India.
Tel : + 91 7272 425100 To 104
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Sales Office
PARAG Fans & Cooling Systems Limited
102, Omshri Apartment, 264, Dharampeth Extension, Nagpur- 440010
Tel : + 91-712-3266125 / 6
Fax : +91-712-6616125
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US Representative Office
PARAG Fans & Cooling Systems Limited
19141 Stone Oak Pkwy, Ste 104
San Antonio, TX 78258
Phone: +1 (210) 544 3594
           +1 (210) 401 8385
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