CASE STUDY

An Engineering company saves 17% of energy consumed by metallic fans - investment of Rs. 5 lakh pays back in 1.5 years.

DEMONSTRATION SITE
An automobiles component manufacturing in Bangalore has 8 DG Sets (2x2,260kVA & 2,260, 4x860 kVA) to serve its entire captive power generation requirements. The plant management identified an air-cooled fluid cooler of 2,260 kVA Conex DG set for the purpose of the Energy Saving Demonstration Project.    
PILOT PROJECT

One of the 2260 kVA DG sets was selected for evaluating the performance of high efficiency aerofoil fan. The 2260 kVA DG set has 2 numbers of FC-W-140 air-cooled fluid coolers for heat dissipation. Together these 2 fluid coolers have 5 fans made of stainless steel and are connected to motors of 5.5 kW each. This DG set operates on an average of about 4,500 hours in a year. The company has monitored the performance of aerofoil fans after installation. The investment is Rs. 1.35 lakh, and the annual energy savings is to the tune of 0.18 lakh kWh.

PERFORMANCE EVALUATION

5 sets of aerofoil fan blades made of PAG material were installed as replacement to the existing SS fans for the 2260kVA DG set under trail. All necessary parameters, viz. energy consumption, fan operating hours, were monitored over a period of time. All the data were downloaded and analyzed. Following table compares the existing SS and  the retrofitted aerofoil fan:

     
Fan diameter, mm 1220 1220
Fan material Stainless steel Glass reinforced polyamide
Fan speed, rpm 945 945
No. of blades 9 4
Blade angle-degree - 20
Static pressure, mm H2O  5(estimate) 5
Design air flow per fan, m3/h 43,000 49,500
Measured air flow per fan, m3/h 41,850 48,000
Rated shaft power per fan, kW 4.0 3.1
Measured fan motor power consumption, kW (for 5 fans) 23.0 19.0
Total  power savings, kW - 4.0
%power savings - 17.4
Fan efficiency,%  32  50
Annual energy savings @ 4,500 operating hours, kWh - 18,000
Annual cost savings @ Rs. 4.30 / kWh, Rs lakh - 0.77
Investment, Rs lakh - 1.35
Simple payback period, years - 1.74
Projected savings for additional 21 fans
Investment, Rs lakh

5.0

Power savings, kW

17.0

Annual operating hours

4,500

Annual energy savings, lakh kWh 

0.765

Annual energy cost savings, Rs lakh

3.29

Simple payback period, years

1.5

 

 

The plant also has another 21 metallic fans of rating between 3.7-5.5 kW serving another 3 DG sets and 7 low-pressure air compressors. Potential exists to save additional 17 kW power.

 

Note: The most important parameter for this investigation is the heat dissipation by the forced air-cooled of the fluid cooler (radiator) fans. The heat dissipation is directly proportional to the product of airflow rate and air enthalpy gain. What is required of the aerofoil fan is to dissipate equal or higher heat from the circulating cooling water at lower power consumption. It was observed that the aerofoil fans have achieved the job they are intended for. As can be seen, the aerofoil fan is found to be delivering 6,150 m3/h of additional air (15% more) compared to the existing SS fans besides savings 17% of energy.
This Demonstration case study is supported by the Indo-German Energy project - a joint initiative of Government of India and Germany, and implemented by Tata Energy Research Institute, Bangalore Center.

The key objective of this programme is to promote cost effective energy saving retrofits and products based on new innovations, technologies and ideas and also those technologies/devices that are cost effective, but do not have the required market penetration due to lack of information about the product. The promotion of these will be through information dissemination and wide distribution of practical case to the potential users. The case studies' results are based on close monitoring of the installation at site over a period, and hence  the savings potential and other parameters are those actually realized. 

For Further Information, Please Contact:
Tata Energy Research Institute
L. N. Complex, 10/1, Palace Road,
Bangalore 560 052, India
Phone:+91-080-225 57 22/+91-080-228 37 64/+91-080-228 38 01. 
Fax: +91-080-225 57 60.
Email: teriblr@giasbg01.vsnl.net.in

 

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