1. ENERGY SAVING IN BASEMENT CAR PARK VENTILATION FOR
A PRESENTATION ON
ENERGY SAVING IN
BASEMENT CAR PARK VENTILATION
FOR
THE ADMINISTRATIVE BUILDING AT
GREAMS ROAD , CHENNAI.

2. ADMIN BUILDING AT GREAMS ROAD, CHENNAI
Proposed Hi-Tech Admn. Bldg Consists of 2 Towers- G+8 / G+5 and has a common lower and upper level Basement
Capacity of Basement – Parking for 157 cars & 97 two-wheelers.
Area of Basement (covers Towers 1&2)
Lower Basement sq.m
Upper Basement sq.m
Ceiling height of basements Mtr

3. Car Parking area in Basements are fully enclosed.
Enclosed Under-ground parking area requires Mechanical Ventilation.
In absence of Ventilation, Parking facility presents several Internal Air Quality problems.
Most serious is the emission of high levels of Carbon-Monoxide(CO)
CO is easily absorbed by Haemoglobin in Human Blood and can Inhibit Oxygen delivery to Body and can cause adverse health effects varying from headache to death

4. CO level- within 29mg/cu.m (25 ppm) with
The NATIONAL BUILDING CODE OF INDIA – 2005 Specifies the following parameters for Ventilation:
CO level- within 29mg/cu.m (25 ppm) with
Peak level not to exceed 137 mg/cu.m.(125 ppm)
As per ASHRAE Max Level for CO
8 hrs exposure – 25ppm
1 Hour exposure- 35 ppm
Air change requirement as per NBC for Basement Car Parking :
9 to 12 ACPH under normal conditions
( For Design purpose 10 ACPH is used)
30 ACPH in case of fire emergency

5. DUCTED VENTILATION
The Conventional Ventilation System is the ducted Ventilation system. This has:
-Provision of Fresh air fan and Exhaust Air Fans with ducting arrangement as per requirement.
- To be operated based on timing control.
- Full capacity of Fans has to be operated irrespective of Smoke level or CO Concentration.

6. DUCTLESS VENTILATION
The Modern method of Ventilation system is the Ductless Ventilation system in which :
- No Ducts are required.
- Only Fresh Air Fans, Exhaust Air Fans and Jet Fans
required.
- CFD(Computational Fluid Dynamics) analysis, is
utilised to decide the number and location of Jetfans for
effective and optimum performance.
- A group of approximately 4 Nos of Jet Fans are
controlled by one CO Sensor and Integrated with IBMS.
- When the CO level exceeds threshold value, CO Sensors extends signal to IBMS and accordingly the corresponding group of Jet Fans are triggered.
- When CO level exceeds threshold value in approximately 50% of CO Sensors per Basement , then Fresh Air/ Exhaust Fans are switched ON through IBMS along with jet fans

7. ADVANTAGES OF DUCTLESS VENTILATION
No ducts: duct system and accessories are eliminated.
Improved air quality and efficient Operation
Optimum use of Car Park Space & Optimisation of Head room for Vehicles and Pedestrians.
Flexibility in installation,quicker installation
Effective smoke management
During Fire Conditions, the volume of air to be handled is of the order of 1.25 lakh CFM. Under this situation ductless system fares better compared to ducted system.

8. How energy saving is achieved in Ductless Ventilation?
Ducts are associated with pressure drop,hence higher size F.A/E.F. are reqd.
Jetfans are located using CFD Analysis in a manner that they help FA/EF to suck/exhaust air respectively, hence smaller size(HP) FA/EFreqd.
During low traffic in Basement, depending upon CO level concentration, only a group of Jetfans may be switched ON by IBMS to distribute/ dilute CO concentration, while in ducted system higher capacity FA/EF have to be kept ON most of the time.

9. JET FAN

10. Construction / Characteristics of a Jet Fan4 4 2 3 2 3 1 5 5
1 - Casing made of Sheet Steel
2- Special silencers at the inlet and outlet side
3- Inlet cone(s)
4- Protection guard(s)
5- mounting brackets for ceiling suspension
Suitable for 300deg C operation for 1 hour
Speed : / rpm – Dual speed
CFM : / 3800
KW : / 1.5
Sound level : / 71 dB
Area Served by each Fan – 280 sq.mtr.(Approx)

11. Comparison between Ducted & Ductless system:

12. Comparison between Ducted & Ductless system:
Ducted system
Operating Cost :
Assumption : All Fans Operation for 2 Hours (Peak Hour), for Balance 6 Hours (Lean Period) Half an Hour ON & Half an Hour OFF.
So, Total operating time=5 hrs/day.
Total unit consumption assuming 5hrs operation/day
=134.7 KW x 5 hrs = KWH/day.
Running cost per annum assuming Rs.7/- per unit rate
= x 25 days X 12 months X Rs.7/-
= Rs. 14,14,350/- per annum.

13. Comparison between Ducted & Ductless system:

14. Comparison between Ducted & Ductless system:
Operating cost :
I.Peak 2 hrs - All jet fans, fresh/exhaust fans ON.
a) Jet fans(32X0.3KW) =9.6 KWX2hrs = units
b) Fresh air and exhaust fan =77.0 KW X 2hrs = units
II. For balance 6 hrs (Fresh air & Exhaust fan OFF)
a)25% (2 groups i.e. approx. 8 fans ) jet fans ON
for 2 hrs =9.6KWX25%x2hrs = units
b)12.5% (1 group i.e. approx. 4 fans ) jet fans ON
for 2 hrs = 9.6KWX12.5%x2hrs= units
c) For 2 hours (consisting of 4 durations of ½ hr. each)
all Fans are OFF = Nil
. Total units/day = units
Energy cost/annum = X 25 days X 12 months X Rs.7/ = Rs. 3,78,840.00
Maintanence Cost for Jet fans p.a = Rs ,000.00
Total Operating Cost per annum = Rs. 4,53,840.00

15. Calculation of Payback period
Ducted Ductless
1. Fresh air & Exhaust fans Rs lakhs Rs lakhs
2. Ducting and electrical panel and cabling,
cable tray,CO sensors. Rs lakh Rs lakhs
3. Jet fans NIL Rs lakhs
Total cost Rs lakhs Rs lakh
Capital cost for ducted System Rs lakhs
Capital cost for ductless System Rs lakhs
Additional capital cost Rs lakhs
Savings in Operating cost/ Annum
by providing jet fans = Rs. (14,14,350/- - 4,53,840/-)
= Rs. 9,60,510/- per annum.
Pay back period = x 12 months
9.60
= months
Or Say 24 months