Experimental performance analysis of flow of air curtain

International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –
6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME
79
EXPERIMENTAL PERFORMANCE ANALYSIS OF FLOW OF AIR
CURTAIN
Mr Nitin Kardekar1
, Dr. V K Bhojwani2
, Dr Sane N K3
1
Principal, Jayawantrao Sawant Polytechnic.Research Scholar, Singhania University
2
Professor JSPM’s Jayawantrao Sawant College of Engineering, Pune
3
Research Supervisor, Singhania University
ABSTRACT
A study is undertaken to establish a relation between the power consumed by air
curtain and the performance of air curtain in terms of discharge air velocity from it. The
prototype experimental set up is established in the laboratory. The series of observations are
made by varying the input voltage and its effect on the output air velocity of the air curtain.
The air velocity forms the invisible barrier of air in the form of curtain which separates the
conditioned and unconditioned environments. The results are displayed in the form of graph.
The graphs are analysed in the light of actual performance and conclusions are drawn from
the study. The study reveals that there is great scope of savings in power consumption by
making small changes in the design of air curtain.
Keywords: air curtain, discharge air velocity, performance of air curtain, power consumption
of air curtain, effectiveness of air curtain.
INTRODUCTION
For the study and analysis of the performance of air curtain, the application chosen is
door way air curtain. The door way air curtains are extensively used in shopping malls,
banks, retail shop etc. The purpose is to restrict the cold/hot air loss from conditioned space
by installing the air barrier. An air curtain device also helps in prevention of dust, dirt or
insects entering in to conditioned spaces. Air curtains are also finding applications in
avoiding smoke propagation, biological controls and explosive detection portals. According
to research by US department of energy, 1875MW energy will be saved per year if super
market display cabinet air curtain will be operated at optimised performance [4] In 2002 the
INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING
AND TECHNOLOGY (IJMET)
ISSN 0976 – 6340 (Print)
ISSN 0976 – 6359 (Online)
Volume 4, Issue 3, May - June (2013), pp. 79-84
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UK food and drinks industry used equivalent of 285 tonnes of oil to power its refrigeration
industry, with most being used in cold storage. In developing countries like India; the rise in
cold storages, super markets, retail stores, banks are not only limited to mega cities but they
have also become the integral part of suburban’s and small towns. The effects of
globalisation are inevitable. The air curtains are no more luxury but are the necessary part of
business development and economy. Hence the study of air curtain with respect to Indian
climate is utmost necessary to ensure optimised performance of air curtains which will lead to
energy conservation. The saving of energy (Electrical energy) will always be boon for energy
starving country like India.
METHODOLOGY
The Technocrat make air curtain for door size W – 950 mm X H – 2530 mm Model 3
ft. HV+ Beta is chosen for the analysis purpose. As shown in Figure 1 the prototype of door
way is manufactured with help of plywood which is supported by MS angle frame. The air
curtain is mounted on the door way. The flow straightener is added in order to reduce the
turbulences in the air flow. In order to reduce direct interference of the suction head of the air
curtain, the suction duct is added as shown in Figure 1. The length of the Suction head is kept
1000 mm from the end of the air curtain device. The power cord of air curtain is connected to
mains through the dimmer stat. Dimmer stat helps in the variation of input voltage to the air
curtain device. The voltage change will change the output of dual motor (i.e. speed of the
shaft). This results in variations of output air velocity of air curtain device. The air velocity in
air curtains is a very important parameter impacting its effectiveness. The input voltage to fan
motor is measured by digital multi meter. The power supplied to air curtain is measured by
the watt meter. In order to measure the air velocity at fixed points, a grid of the thread is
placed in air flow path of air curtain. This facilitates to measure the velocity of air flow of air
curtain when input parameters are varied. With help of grid it is easy to find the location of
point in the space for measurement of velocity at different input voltages. The input voltage is
varied from 125 V to 225 V with increment of 25 Volts. The speed of the fan is measured
using digital Tachometer and the velocity is measured using digital anemometer. All the
instruments are calibrated before use. The entire experimentation is carried out at isothermal
conditions; ambient air at 240
C ( + 10
C) at one atmosphere.
RESULT AND DISCUSSION
The prototype experimental set up is established in the laboratory. The series of
experimentation is carried out in the laboratory. In the observation, the input voltage thereby
power to air curtain is varied and its effect on discharge air velocity of air curtain is observed.
The voltage is varied in the steps of 25V with the help of dimmer stat. The speed of the
centrifugal fan of the air curtain is measured with tachometer. The discharge air velocity is
measured with the help of turbine type anemometer in m/s. The observations and results are
presented graphically. Figure 2 shows the graph of Input voltage verses the power input to air
curtain. Figure 3 shows the graph of Input voltage verses speed of the centrifugal fan of air
curtain motor. Figure 4 shows the graph of Input voltage verses discharge air velocity of the
air curtain. From figure 2 it is clear that, as input voltage is increased, the input power also
increases. At 125V input the input power observed is 50 watts where as at input voltage 225
V it increases to 100 watts. At input of 175 V the input power recorded is 70 watts and at

International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May
input voltage of 200 V the input power is 90 watts.
air curtain is increased the power consumed by the motor is also found increasing. Figure 3
shows the graph of input voltage verses the
input voltage increases the fan speed is also increase
the fan speed is 822 rpm. It reaches to 1432 rpm
volts fan speed stabilises even for i
voltages of 200 V and 225 V the fan speed is 1460 rpm and 1468 rpm respectively.
even though there are increments of 25 V and 50V
are only 28 rpm and 36 rpm. The graph of output
velocity of 3.3 m/s and 5.2 m/s is measured at input voltage of 125V and 150 V. It increases
to 9.2 m/s at input voltage 175 V. A marginal increment of 0.4 m/s and 0.6 m/s is observed
for the further increment in the input voltage of 25 V and 50 V respectively. Thus output
velocity stabilises beyond 175 V.
velocity of the air curtain reveals all these details
should run the air curtain near optimum voltage to
can be used, without affecting the performance of air curtain
form barrier of moving air to separate the two environments.
out of the air curtain device decides the quality of barrier. Higher the velocity, more robust is
the air curtain barrier. From abo
the discharge air velocity when it is operated at 175 V, 200 V and 225 V. Thus we can say
that equally strong air curtain can be obtained when
voltage of 175 V. The further
substantial improvement in the discharge
Figure 1
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME
81
nput voltage of 200 V the input power is 90 watts. Thus as input voltage to fan motor of the
graph of input voltage verses the speed of the centrifugal fan. It is observed that
the fan speed is also increases initially. For the input voltage of 125 V
the fan speed is 822 rpm. It reaches to 1432 rpm for the input voltage of 175 V. Beyond 175
stabilises even for increased input power to air curtain device.
V and 225 V the fan speed is 1460 rpm and 1468 rpm respectively.
though there are increments of 25 V and 50V in input voltage, the fan speed increments
The graph of output air velocity also shows similar nature. The
for the further increment in the input voltage of 25 V and 50 V respectively. Thus output
175 V. Figure 4 is the graph of input voltage verses the output air
reveals all these details. It is clear from above discussion
should run the air curtain near optimum voltage to save the power else the lower power motor
be used, without affecting the performance of air curtain. The air curtains are provided to
form barrier of moving air to separate the two environments. The velocity of the air coming
decides the quality of barrier. Higher the velocity, more robust is
the air curtain barrier. From above discussion it is clear that there is not much difference in
air velocity when it is operated at 175 V, 200 V and 225 V. Thus we can say
that equally strong air curtain can be obtained when the device is operated even at
f 175 V. The further increase in input of power will merely be waste
discharge air velocity.
Figure 1: Photo of the Experimental set up
June (2013) © IAEME
Thus as input voltage to fan motor of the
It is observed that, as
initially. For the input voltage of 125 V
for the input voltage of 175 V. Beyond 175
For the input
V and 225 V the fan speed is 1460 rpm and 1468 rpm respectively. Thus
the fan speed increments
shows similar nature. The
for the further increment in the input voltage of 25 V and 50 V respectively. Thus output air
is the graph of input voltage verses the output air
from above discussion that one
save the power else the lower power motor
The air curtains are provided to
The velocity of the air coming
decides the quality of barrier. Higher the velocity, more robust is
ve discussion it is clear that there is not much difference in
air velocity when it is operated at 175 V, 200 V and 225 V. Thus we can say
evice is operated even at the input
waste without

82
Figure 2: Input Voltage Vs Power
Figure 3: Input Voltage Vs Fan Speed

83
Figure 4: Input Voltage Vs air Velocity.
The optimum voltage there by optimum performance for this model is found to be at
175 V. During experimentation it was observed that the power required by the air curtain
device increases with increase in voltage. The power required at 175 V is 80 watts. At 200 V
and 225 V power consumed is 90 watt (12.5% more) and 100 watt (25% more) respectively.
But there is hardly any improvement observed in terms of air velocity (2% and 4%
respectively). Hence it is recommended to use lower capacity motor without affecting the
performance of the air curtain device. As discussed earlier the air curtain devices are
extensively used across the globe to protect the conditioned environment. The millions of air
curtain are functioning at the malls, banks, commercial places, cold storages etc. If air
curtains devices are shifted to use lower capacity motors at optimised conditions as discussed
in the paper without affecting their performance then the huge electrical power will be saved.
Using lower power consumption motor for air curtain applications will certainly reduce the
demand of the electricity in larger extents for these commercial spaces.
CONCLUSION
The output of the air curtain device is measured in terms of velocity of air. The input
power is varied and efforts are made to optimise the performance of the air curtain device. It
is concluded that instead of adopting the generalised approach for designing and installation
of air curtain device, it is necessary to design the air curtain device considering the particular
application. This will ensure the use of the lower capacity and lower power consumption
motor for air curtain devices for a given application. Considering the extensive use of the air
curtain devices in the entire world the demand of the electricity will be certainly reduce in the
larger extents. And thus millions of dollar will be saved in energy bills globally.
0
2
4
6
8
10
12
100 125 150 175 200 225 250
Maximumvelocityinm/s
Input voltage to fan motor
Input voltage vs discharge air velocity

84
REFERENCES
[1] Tassou, S. A. and Pappas T. C., ‘Numerical Investigations into the Performance of
Doorway Vertical Air Curtains in Air-Conditioned Spaces’, ASHRAE Transactions,
Vol. 109, No. 1, 2003, pp. 273–279.
[2] Y. T, Ge, and S A Tassou,’Simulation of the performance of single jet air curtain for
vertical display cabinets’, Applied Thermal Engineering, Vol. 21,2001 pp.201-219.
[3] Field B. & Loth, E., ‘Entrainment of refrigerated air curtains down a wall’,
Experimental Thermal and Fluid Science, 30, 2006, pp. 175-184,.
[4] Dr. Homayun K. Nawaz, Dr. Dana Dabiri Mazyar Amin and Ramin Faramarzi ‘Past,
Present and future Research towards air curtain performance optimisation’, OR-05-
16-4.
[5] Hampl, V., Johnston, O. E. and Murdock, D. J., Jr, ‘Application of an Air Curtain-
Exhaust System at a Milling Process,’ American Industrial Hygiene Association
Journal, Vol. 49, No. 4, 1988, pp. 167–175.
[6] Etkin, B. and McKinney, W. D., ‘An Air-Curtain Fume Cabinet’, American
Industrial Hygiene Association Journal, Vol. 53, No. 10, 1992 pp. 625–631
[7] A. Aubert and C. Solliec, ‘Push-Pull Air Curtain Performances for VOCs
Containment in an Vol 4, No.1 2011, pp.43-50, (ISSN 1735-3645)
[8] Mr Nitin Kardekar and Dr Sane N K, ‘Effect of humanoid shaped obstacle on the
velocity profiles of flow of air curtain’ International Journal of Mechanical
Engineering and Technology, Volume 3, Issue 3, 2012, pp. 511-516, ISSN Print:
0976 – 6340, ISSN Online: 0976 – 6359
[9] Kapil Chopra, Dinesh Jain, Tushar Chandana and Anil Sharma, “Evaluation of
Existing Cooling Systems for Reducing Cooling Power Consumption”, International
Journal of Mechanical Engineering & Technology (IJMET), Volume 3, Issue 2, 2012,
pp. 210 - 216, ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359.

Experimental performance analysis of flow of air curtain

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