Leela Report 14 June

May, 2010

Study Conducted under “Scheme on promotion of energy audit in

Private, Govt., Semi-Govt., Industrial, Institutional, Commercial

buildings”

2010

ANSH ENERGY SOLUTIONS PVT. LTD.

[ Investment Grade Energy Audit Report of M/S

Ambience Resorts (P) Ltd. (Leela Kempinski), Gurgaon ]

2

ANSH ENERGY SOLUTIONS PVT. LTD.

[email protected]

COMPREHENSIVE ENERGY AUDIT

OBJECT: EFFICIENCY TESTING OF BOILERS, HVAC &

LOSS IDENTIFICATION IN ELECTRICAL DISTRIBUTION

SYSTEM

CLIENT: M/S Ambience Resorts (P) Ltd. (Leela Kempinski),

Gurgaon

May, 2010

Study Conducted under “Scheme on promotion of energy audit in Private,

Govt., Semi-Govt., Industrial, Institutional, Commercial buildings”

Audit conducted by:Audit conducted by:Audit conducted by:Audit conducted by:

ANSH ENERGY SOLUTIONS PVT. LTD., Gayatri Dham, Lower Bazar, Modinagar – 201204 (UP)

Auditor BEE Registration: Auditor BEE Registration: Auditor BEE Registration: Auditor BEE Registration: EAEAEAEA----10465 (Anubhav Gupta) & EA10465 (Anubhav Gupta) & EA10465 (Anubhav Gupta) & EA10465 (Anubhav Gupta) & EA----

3267(Anshul Singh Yadav)3267(Anshul Singh Yadav)3267(Anshul Singh Yadav)3267(Anshul Singh Yadav)

3

AACCKKNNOOWWLLEEDDGGEEMMEENNTT

Investment Grade Energy Audit has been done with the objectives to identify & quantify the energy saving opportunities for M/S Ambience Resorts (P) Ltd. (Hotel Leela Kempinski), Gurgaon, Haryana. We would like to thank Mr. Anil Kumar, Director of Engineering, Leela Kempinski, Gurgaon, Mr. Rajesh Yadav, Mr. Vinay and entire engineering department team for their steadfast support extended to us. We would like to convey our special thanks to field staff for their inputs.

Energy Audit Team Anubhav Gupta

Anshul Singh Yadav Vikram Pal Singh

4

Abbreviations

ACs Air Conditioners

BEE Bureau of Energy Efficiency

M3/hr Cubic Meter Per Hours

FTL Fluorescent Tube Light Lamp

HPSV High Pressure Sodium Vapour

KVA Kilo Volt Ampere

KWH Kilowatt Hour

KVAH Kilo Volt Amperes Hour

KVAr Kilo Volt Amperes Reactive

KW Kilo Watt

LPD Litres Per Day

MW Mega Watt

O&M Operation and Maintenance

P.F Power Factor

PV Photo Voltaic

SPC Specific Power Consumption

STC Standard Test Condition

SWH Solar Water Heater

SQ. M. Square Meter

TR Ton of Refrigeration

DHBVNL Dakshin Haryana Bijli Vittran Nigam Limited

V Volt

5

CONTENTS

1 EXECUTIVE SUMMARY 1.1 The Leela Kempinski 7

1.2 Scope Of The Audit 7

1.3 Baseline Energy Consumption 7

1.4 Assessment Of Energy Consuming Equipment 8

1.5 Energy Saving Proposals 11

2 INTRODUCTION

2.1 The Leela Kempinski 12

2.2 Objective 12

2.3 Scope 13

3 ENERGY AUDIT METHODOLOGY 3.1 Energy Audit Methodology 14

3.2 Energy Management Action Plan 15

4 OBSERVATIONS AND RECOMMENDATIONS 4.1 Steam Boiler 16

4.2 Hot Water Boiler 23

4.3 Boiler Feed Water Pump 25

4.4 Cooling Tower 26

4.5 Transformer 29

4.6 Diesel Generator 31

4.7 Earthing 32

4.8 Power Factor 33

4.9 Motor Efficiency And Loading 38

4.10 Harmonics 43

5 Appendix 46

1 Schematic line diagram i

2 Electricity bill analysis ii

2a Average unit consumption per day iii

2b Maximum demand curve iii

2c Average energy charges per day curve iv

3 HSD consumption pattern v

3a HSD consumption steam boiler curve v

3b HSD consumption HW boiler curve vi

3c Specific oil consumption of DG vi

3d Total HSD consumption vii

3e Total HSD consumption & DG HSD consumption curve vii

6

4 Diesel generator set viii

5 Harmonics x

6 Power Factor improvement with static capacitors xiii

6a Methods of testing & checking capacitors xviii

7 Motor efficiency test xx

8 Performance evaluation of motors xxvii

8a Measures to improve efficiency of motors 7 distribution system xxix

9 Maintenance schedule of motors xxxii

10 Cooling towers xxxiv

11 Sample proposal from KSB pumps xxxvi

12 Sample proposal for PHE xxxix

7

11.. EEXXEECCUUTTIIVVEE SSUUMMMMAARRYY

1.1 THE LEELA KEMPINSKI

The Leela Kempinski Gurgaon, Delhi (NCR) is among the prestigious luxury Hotel in Delhi

(NCR), strategically located at the Delhi - Gurgaon border, with the capital city on one

side and Gurgaon’s established business district on the other. It has 322 rooms and

suites and 90 service apartments.

1.2 SCOPE OF AUDIT

The energy audit is utility specific and broadly covers the following area:

• Steam Boilers

• Hot water boilers

• Motors

• Pumps

• Electrical distribution network

• HVAC system

1.3 SUMMARY OF THE BASELINE ENERGY CONSUMPTION

The major equipment being used in the Hotel is as follows

1. Steam Boilers of 0.85TPH steam capacity 8 kg/cm2: 3 nos.

2. Water Boilers of 500000 Kcal with max. operating temperature of 80° C: 2 nos.

3. Diesel Generators of 1500KVA: 3 nos.

4. Transformers of 1600 KVA: 3 nos.

5. HVAC systems of 375 TR and 700 TR: 2 nos. each

Apart from the above listed equipments there are number of motors and pumps,

electrical panels and other auxiliaries are operating round the clock to keep the Hotel

running.

8

Summary of the Baseline Energy Consumption

1 Average annual electricity consumption 198588 kWh

2. Average annual total HSD consumption 3466937 ltr

3. Average annual HSD consumption for steam generation 551729 ltr

4. Average annual HSD consumption for water heating 154964 ltr

5. Average annual HSD consumption for electricity generation 2760241 ltr

1.4 ASSESSMENT OF ENERGY CONSUMING EQUIPMENTS

1.4.1 Steam Boilers

The boiler in this report is referred as Boiler No. 1, 2 & 3 (Thermax Steam Boilers). The

efficiency was calculated as below:

Boiler 1 Boiler 2 Boiler 3

Average Efficiency

Without ID Fan

operation

84.36 %

84.12%

86.56%

With ID Fan

operation 80.12% 79.70% 82.96%

The operation has been observed carefully and few areas of improvement have been

observed. Their efficiency can be further enhanced to 88% through the

recommendations given in report.

1.4.2 Hot Water Boilers

Two hot water boilers are operated for supplying hot water in the guest room area for

guest’s comfort. These Boilers are Thermax make, non IBR, HSD fired, water tube

boiler with maximum operating Temp. 80° C and are operated to maintain hot water

supply temperature of 55-60oC.

9

1.4.3 Condensate Recovery System

The condensate from main kitchen and laundry is collected in condensate tank and its

heat is exchanged by circulating this water through primary clarifier and then this

condensate is discharged in the drain @ 1350ltr/hr.

The condensate recovery is approximately 75-80% and temperature of drained

condensate is around 96°C. The heat content in this condensate is 118637473.8 Kcal.

1.4.4 Transformers

There are 3 nos. 11kv/433 v, 1600 KVA naturally air cooled transformers installed in the

basement of the premises. The secondary of the transformer is connected with the

bus bar which supplies to the main LT panel. As the bus bar and the LT panel are

not accessible the measurement of the output parameters has not been taken.

However, the temperature of the transformer winding was taken and was found

(109°C) significantly high then the average ambient temperature (90°C).

1.4.5 Motors

The measurements of 18 motors were of various ratings ranging from 45 KW to

11 KW was taken. The average efficiency and loading of the motors is 84.59% and

83.9% respectively. The current and voltage harmonics of the individual motors

were measured. The total current harmonics distortions are under prescribed

limit but the total voltage harmonics distortions of 7 motors are more than 49%.

1.4.6 Pumps

Hotel Leela utility is using more than 50 centrifugal pumps for various applications

and their capacity is from 10m3/hr to 475 m3/hr average pumps efficiency was

observed ~ 77% .

10

1.4.7 Cooling Towers

There are 7 cooling towers operating, 4 for HVAC, 2 for DG sets and 1 dedicated

to cold room operating efficiency of cooling tower is as follows:

HVAC CT-1 HVAC CT-2 HVAC CT-3 HVAC CT-4 Cold Room

CT Range 0.2 4.2 3.9 3.2 2.6

CT Approach 8.6 4.6 4.8 5 4.4

% CT Effectiveness = 2.27% 47.73% 44.83% 39.02% 37.14%

1.4.9 Diesel Generator Set

There are three Cummins DG sets of 1500 KVA capacity each installed in the basement

of the premises.

Hotel Leela D.G. Set Details

Sr.No Make Kva Amp Volt PF Fuel

Used %Load

Engine

BHP

Power

KW

1 Cummins 1500 1409/968/1370 418 0.9 HSD 70 1735 834

2 Cummins 1500 1130/1135/1089 423 0.87 HSD 60 1735 732

3 Cummins 1500 1240/1248/1230 420 0.88 HSD 66 1735 790

The facility uses Cummins make DG sets for which quoted average of 3.8 to 4.2

units/liter of HSD is easily achievable. We have observed an average of 3.51

units/liter of HSD which is on the lower side.

1.4.10 Electrical Distribution System

The rising mains and other main feeders of the LT PCC were analyzed with the help of 3

phase Power Analyzer. The various parameters like KW, PF, voltage and current

harmonic distortions were measured. The total voltage and current harmonic

distortions are under the permissible limit. But the average PF of the various feeders is

0.84 lagging ranging from 0.55 to 0.90. For SCHEMATIC ELECTRICAL DISTRIBUTION LINE

DIAGRAM refer Appendix -1

11

1.5 ENERGY SAVING PROPOSALS

The summary of the annual energy savings identified is as under:

Total Annual Savings (9 proposals) : Rs. 242.55 Lakhs

Annual savings without investment (2 Proposals) : Rs. 13.04 Lakhs

Annual savings with investment (8 Proposals) : Rs. 241.93 Lakhs

Investment Required : Rs. 30.28 Lakhs

Average payback period for capital proposals : 2 Months*

*For capital proposals only

SNO. ENERGY SAVING PROPOSAL ANNUAL

SAVINGS

INVESTMENT

REQUIRED

SIMPLE

PAY BACK

PERIOD

Rs. Rs. Months

1 Installation of oxygen analyzer for

steam boiler 11,86,560 2,70,000 2.73

2a Condensate recovery 12,42,396 nil Immediate

2b

Heat exchanger between condensate

and fresh water for supply to guest

rooms

39,78,000 90,000 10 days

2c Installation of solar water heater 7,57,000 8,64,000 14

2d Installation of WHRU at Ambience mall

generators 195,00,000 195,00,000 12

3 Plunger pump replacement for Boiler

feed pump 1,81,440 1,00,000 7

4 Automation of condenser pumps 76,03,200 11,00,000 2

5 Maintaining transformer at ambient

temperature 62,015 nil Immediate

6 Installation of high efficiency generator

cooling water pump 1,71,720 27,000 2

7 Separate earthing pits for each

generator earthing point and panels 79,83,744 3,75,000 17 days

8 Installation of capacitors at HVAC MCC

Panel 14,93,316 1,50,000 1 month

9 Replacement of large motors with high

efficiency motors 15,94,680 9,24,182 7months

12

22.. IINNTTRROODDUUCCTTIIOONN

2.1 THE LEELA KEMPENSKI

The property is combination of three distinct zones, all serving different purposes:

• The guest room area, individual spaces, with extensive glazing, asynchronous

utilization and varying energy loads.

• The public area (reception hall, lobby, restaurants, meeting rooms, swimming

pool, spa etc.) space with a high rate of heat exchange with the outdoor

environment (thermal losses) and high internal loads (occupants, appliances,

equipment, lighting)

• The service area (kitchen, offices, store rooms, laundry, staff facilities, machine

rooms and other technical areas) – energy intensive requiring advanced air

handling (ventilation, cooling, heating).

To provide guests with high level of multi-facetted comfort and exclusive amenities and

facilities, hotel is having complex installations of utilities such as: Steam system, hot and

service water system, HVAC system and Electricity (Grid power & DG). The utilities are

looked after by engineering department of the company, headed by Mr. Anil Kumar

(Director Engineering), Mr. Kumar and his Team members who are committed to

provide their customers a memorable experience without losing the sight for energy

conservation and waste reduction for betterment of company as well as environment.

2.2 OBJECTIVE OF THE ENERGY AUDIT

The main objective of this exercise is to optimize specific fuel consumption and to

achieve a reduction in recurring expenditure on energy to improve business viability by

plugging the waste energy and through improvement in the operational and

maintenance practices of the facility.

13

2.3 THE SCOPE OF THE ENERGY AUDIT

The aim and scope of audit is to quantify the fuel and energy consumption of the

facility. It further aims to identify the loss avenues in the systems and establish total and

specific steam generation, boiler efficiency monitoring, load balancing, run-ability

optimization and achieving best possible fuel to steam ratio. The audit will thus cover

parameter detection of:

1. Feed water inlet flow.

2. Blow Down flow estimation (If possible).

3. Inlet air temperature.

4. Temperature of exhaust to stack.

5. Feed water quality.

6. Cycle of concentration

7. Variance in phase loading of motors ACB’s and Transformer

8. Operation of motors

9. Losses due to poor capacitor behavior or installation faults.

10. Load curves.

The completion of audit will achieve identification of all types of boiler losses and

possible ECOs (Energy Conservation Opportunities). It will highlight the efficiency

improvement possibilities in motors, capacitors and voltage variations.

The Audit has been done specifically for the steam generating unit, HVAC and Electricity

Load Distribution.

This inspection report reflects the conditions of the equipment at the time of the inspection only.

Please note that equipment conditions change with time and use and the conditions noted in this

report may change in appearance and severity as time progresses or with mishandling. Hidden or

concealed defects cannot be included in this report. An earnest effort was made on our behalf to

discover all fallacies; however in the event of an oversight no liability is acceptable. No warranty is

either expressed or implied. This report is not an insurance policy, nor a warranty service.

14

33.. EENNEERRGGYY AAUUDDIITT MMEETTHHOODDOOLLOOGGYY

3.1 ENERGY AUDIT METHODOLOGY

ANSH ENERGY SOLUTIONS PVT. LTD, conducted the investment grade energy audit

study for the Hotel Leela Kempinski, Gurgaon during May, 2010. As a part of the study,

the energy audit team visited the premises for undertaking performance assessment of

various energy consuming equipments installed in the building using sophisticated

energy audit instruments. The following methodology was adopted for successful

conduct of the study:

• Monitoring of energy related parameters of various equipments using

sophisticated and portable energy audit instruments.

• Online measurement of operating data with various instruments.

• Collection of details regarding electricity consumption in the past, maximum

demand and power factor.

• Discussion with concerned officials to take note of energy conservation activities

already undertaken, if any.

• Critical analysis of data collected during field visit.

o Identification of opportunities having possible energy conservation

potential and quantification of energy losses.

o Identification of suitable measures for reducing energy consumption.

o Preparation of financial analysis for recommended measures.

15

3.2 ENERGY MANAGEMENT ACTION PLAN

16

44.. OOBBSSEERRVVAATTIIOONNSS AANNDD RREECCOOMMMMEENNDDAATTIIOONNSS

4.1 STEAM BOILER

The efficiency of the steam boilers has been calculated through Indirect method and

has been tabulated below.

Boiler 1 Boiler 2 Boiler 3

Average Efficiency

Without ID Fan

With ID Fan

84.36 %

80.12%

84.12%

79.70%

86.56%

82.96%

Efficiency Calculation

As it is know that the efficiency is the ratio of output to input of the system and is

invariably used to assess the system performance. There are two methods to calculate

it:

1. Direct method and

2. Indirect method.

In direct method the output and input of the system/equipment are measured

individually to calculate its efficiency. Where as in indirect method the various losses

are measured and are subtracted from the input to arrive at efficiency.

Here we have followed the indirect method to calculate the efficiency and in the

process quantify the major losses as well.

17

The various types of losses are explained below:

19

The ultimate analysis of the fuel was conducted and the result obtained has been

tabulated below:

Ultimate analysis of fuels:

Content HSD as fuel

Carbon % 86.65

Hydrogen % 13.3

Nitrogen % 0

Oxygen % 0

Sulphur % 0.05

GCV (Kcal/KG) 10730

20

The calculated losses are as follows

a) Dry Flue Gas Loss

Boiler 1 Boiler 2 Boiler-3

11.77% 12.44% 9.01%

7.78% 7.42% 5.54%

b) Loss Due to Hydrogen in fuel


7.29 % 6.51% 7.28%

c) Loss due to moisture in fuel


0 % 0 % 0 %

d) Loss due to moisture in air


0.32 % 0.34% 0.25%

0.22% 0.20% 0.15%

e) Approx. heat loss due to surface radiation and leakages


0.5 % 1.0% 0.5%

Alternative 1

Calculations of tentative and stepwise investment:

The major losses of boilers are clearly evident to be dry flue gas loss, blow down

losses. The suggested tasks to be taken care of shall be:

a) To counteract dry flue gas loss we shall control the excess air (Presently in

the range of 144% to 52 %) supplied to the furnace by adjusting fan speed

balances and by continuous monitoring of the excess oxygen going into the

flue gases. An estimated 1% reduction in excess oxygen shall bring about 0.9%

reduction in loss. Stack monitoring can be done

The suggested methodology of improvement is diagrammatically represented

as below:

b) Loss due to moisture in air is beyond manual control as it is purely based on

atmospheric conditions. The only precaution that can be taken is to avoid any

spray or source of water on suction side of FD fan.

c) The list of improvements suggested is not exhaustive and can be revisited.

Further suggested approach is pinch analysis.

Approximate costs of

Equipment

Oxygen probe

(continuous)

Vigilant Feed water

monitoring


reduction in loss. Stack monitoring can be done online oxygen scanner


Loss due to moisture in air is beyond manual control as it is purely based on


source of water on suction side of FD fan.

The list of improvements suggested is not exhaustive and can be revisited.

Further suggested approach is pinch analysis.

Approximate costs of equipments and payback periods

Tentative Cost Payback period

INR 2,70,000/- 2.73 months

INR ZERO

Start

Installation of furnace draft Pr. Gauge & Fixed Oxygen

Analyser

Vigilant Feed Water Temp monitoring

Vigilant ID fan monitoring w.r.t. furnace draft and flue

gas O2 Level

Stop

21


scanner.


Loss due to moisture in air is beyond manual control as it is purely based on


The list of improvements suggested is not exhaustive and can be revisited.

equipments and payback periods

Payback period

22

Pay back calculations

Steam produced by two boilers of 800 kg/hr at 90% load = 1440 kg/hr

Average operating hours per day = 15

Thus steam produced in a month = 1440 x 15 x 30 = 648000 kg

To produce this steam an average of 48000 litres of HSD is being used. i.e. INR

16,00,000 per month.

Thus cost of one kg of steam = INR 2.47.

1 % improvement in efficiency = INR 16000 per month

Now by reducing the excess oxygen from 12 % to 3% the dry flue gas loss falls

from 11.77 % to 5.59% i.e. savings of 6.18% = INR 98,880 per month.

REDUCING THE EXCESS OXYGEN FROM 12% TO 3% RESULTS IN SAVINGS of INR 98,880

per MONTH

Alternative 2

Now, 1 litre diesel = 0.82 kg = (10730 kcal/kg x 0.82) = 8800 kcal.

Average Condensate drain at 90 oC if recovered against cold stream and discharge

is maintained at 45 oC, total heat saving

� �� ∆�

� 1350 � 15 � 1 � 45 � 911250 �� !

Thus, loss per month due to condensate drain is = 911250 x 30 = 2,73,37,500 Kcal

Now calculating in equivalent litres of diesel = 27337500/8800 = 3106 Litres of diesel

every month.

Thus condensate recovery or heat reuse will result in saving of 3106 x 33.33 = INR

103533 per month.

CONDENSATE RECOVERY RESULTS IN SAVING OF INR 103533/MONTH

23

4.2 HOT WATER BOILER

Alternative 1:

We consider to heat fresh water for use in guest rooms which otherwise is supplied by

HWB 1 & 2.

Assuming water is to be heated from 30 oC to 55

oC.

Creating heat balance equation

"#$%&'%()*' � �� ∆

� "+,'(- .)*', � �� /� 0�� ∆

Thus, 1350 x 1 x 45 (assuming Condensate temp difference of 45) = Q x 1 x 25

Thus QWater = 2430 litres per hour.

The working of condensate cycle is 15 hours, hence availability of hot water = 2430 x 15

= 36.45 KL per day

The total requirement of hot water is nearly 47 KL per day.

Therefore, we reduce diesel consumption of HWB by nearly 65% and close operation of

one diesel HWB.

As per the data collected and the historical data Average monthly diesel consumption

for HWB = 500 x 30 = 15000 litres.

Saving of 65% implies 15000 x 0.65 litres i.e. 15000 x 0.65 x 34 rupees = Rs. 331500.

Thus a savings of Rs. 331500 can be achieved through exchange of heat between

condensate and fresh water.

A plate type heat exchanger can result in the above savings for cost of Rs. 90,000

approximately.

This will result in a simple payback of less than 10 days.

HEAT EXCHANGER WILL SAVE INR 331500/MONTH

Alternative 2

Furthermore the balance quantity of water can be made by using solar water heater of

1000 litre per day capacity on roof top, the solar heater on average working of 8 hours a

24

day will provide 1 KL per day round the year. Thus 16 heaters together will provide 16KL

deficit. Solar Water Heater will require capital cost of Rs 30,40,000 and after subsidy

from State government and Government of India will cost nearly Rupees 8.64 lacs.

Hence an investment of Rs. 8,64,000 will result in saving of balance 35% of cost i.e. Rs.

1,78,500 per month. This saving can be achieved at least 10 months per year.

Table: Details of saving from Solar Water Heating System

Hotel Leela

Capacity to be installed(in LPD) 16,000

System output temperature required (in degree C) 60

Ambient temperature (in degree C) 30

Amount of Energy required to heat 16,000 litres (in Kcal) 480,000

Amount of Energy in 1 Litre of diesel (90% efficiency) 7,900

Amount of Diesel saved per day(in litres) 61

Cost of diesel per litre 34

Amount of money saved annually(in Rs) 7,57,010

Cost of solar heating system (for 16,000 LPD) in Rs. 3,040,000

Capital Subsidy support from State & Central Govt. in Rs. 2,176,000

Effective Capital investment of SWHS in Rs. 864,000

Total Saving in first year

7,57,010 + Saving on account of

depreciation in first year

Payback period Less than 14months

SOLAR WATER HEATER WILL HAVE A SIMPLE PAY BACK PERIOD OF 14 MONTHS

Alternative 3:

As per the site inspection and site conditions we have observed that M/S Ambience Mall

has installation of 4000 KVA of electrical power generation using Cummins diesel

engines. The exhaust of these gensets is being let to the atmosphere without heat

recovery.

We propose that if the managements of both entities can reach a decision the heat can

be recovered for use in hotel as the running hours are same as the steam demand

hours.

25

The generators have a steam generation capacity of 4 TPH at 10 kg/cm2 with 20 oC as

superheat. As the mall is between 500 and 1000 mtrs a 20 degree superheat will be

sufficient for heat transmission. The proposal involves installation of steam generators

by heat recovery by Leela Kempinski for 1.75 TPH. The total cost of project with super

heaters and pipe lines is estimated to be 1.9 crores.

The monthly savings from closing down HSD based steam generators will be nearly Rs.

16.25 lacs per month. Thus the estimated simple payback is nearly 12 months.

This is an attractive payback for steam generation facility and is highly recommended.

INSTALLATION OF WHRU AT AMBIENCE MALL GENERATORS WILL SAVE RS. 16.25

LACS.\MONTH

4.3 BOILER FEED WATER PUMP

As per the observation the installed plunger pump is of the rating of 5KW. However as

per the demand specs if we calculate the power requirement using 1.5 m3/hr as

required flow rate and 125 mtr head it comes out to be 1.27 KW and motor required is

1.5 KW. Attached with report is a sample proposal from KSB pumps.

The savings are 3.5 KW i.e. 56 KWH per day. Thus the monthly savings are Rs. 7560/-

The cost of pump is Rs 50,000 and hence the payback is 6.6 or says 7 months.

PLUNGER PUMP REPLACEMENT WILL HAVE SAVING OF 7 MONTHS

Standard Calculations and Assumptions

1. The calculations along with formulae are mentioned above.

2. Calculations for payback have been done taking in consideration simple payback

only as the payback is extremely fast and IRR calculations are not significant.

3. It is assumed that the equipment suggested shall be allowed to work properly

with adequate staff training or else the payback calculations may vary.

26

SWOT Analysis

Situation being analyzed: ____Boiler Efficiency Improvement_________

STRENGTHS WEAKNESSES

1. Sufficient Capacity installed. 2. Availability of down time for installation

of additional equipments as interconnecting pipeline is already installed.

3. Willingness of management for improving existing set-up

1. Unavailability of process instrumentation.

2. Unavailability of design data.

OPPORTUNITIES THREATS

1. Vast scope of improvement of efficiencies. 2. Reduction of loss can be achieved by

using instrumentation and monitoring. 3. Monitoring instruments are readily

available in market so no long lead times.

1. Instrumentation if installed might not work properly due to lack of monitoring or knowledge.

2. Biased mindset regarding possibility of improvements, and tendency of searching of easier solutions.

4.4 COOLING TOWERS

Observations

HVAC CT-1 HVAC CT-2 HVAC CT-3 HVAC CT-4 Cold Room

Inlet Cooling Water

Temperature °C

30.1 30.1 30.1 29.6 28.3

Outlet Cooling Water

Temperature °C

29.9 25.9 26.2 26.4 25.7

Air Wet Bulb Temperature

near Cell °C

21.3 21.3 21.4 21.4 21.3

Air Dry Bulb Temperature

near Cell °C

40 40 40.1 40.1 40

Number of CT Cells on line

with water flow

2 2 1 1 1

Total Measured Cooling

Water Flow m3/hr

485 425 432

CT Range 0.2 4.2 3.9 3.2 2.6

CT Approach 8.6 4.6 4.8 5 4.4

% CT Effectiveness = 2.27% 47.73% 44.83% 39.02% 37.14%

Range X 100

Range + Approach

TR 31.5 0.0 537.5 448.2 0.0

27

It has been observed that CT 1 is either choked or there is some operational fault. The

HVAC system of hotel can deliver the TR only if cooling tower allows it to. Thus this can

create the bottle neck. As per the design values we have two HVAC of 375 TR and two

HVAC of 700 TR. Now at the time of observation HVAC 3 & 4 were being operated which

are both rated at 700 TR.

Thus as per the observation we were running 1400 TR but effective TR obtained due to

CT bottleneck was 537.5 + 448.2 i.e. 985.7 and still consuming 800 KW.

Now we can improve the condition by either varying the flow rate of water of by varying

the inlet temperature of cooling tower so that the tower dissipates nearly 700 TR. The

calculations are as follows:

Temp vs TR 1 2 3 4 5

Inlet hot water temp 30.1 29 31 32 33

Outlet cold water temp 26.2 26.2 26.2 26.2 26.2

Water flow rate 425 425 425 425 425

TR 537 385 661 799 937

Flow rate vs TR 1 2 3 4 5

Inlet hot water temp 30 30 30 30 30

Outlet cold water temp 26.2 26.2 26.2 26.2 26.2

Water flow rate 350 400 450 500 545

TR 442 505 569 632 689

0

100

200

300

400

500

600

700

800

900

1000

29 30.1 31 32 33

TR vs Temperature

TR

28

Thus the best results in this case be achieved by using VFDs to control the water flow

rate and discharge temperatures. As per the above data if cooling towers work properly

we may need only 700 + 375 TR to achieve desired TR and saving nearly 200 KW.

Thus daily savings = 200 x 24 = 4800 KWH per day or 144000 kWH per month

Hence savings of 144000 x 4.4 per KWH = Rs. 6,33,600/- per month

Tentative investment in optimization and automization = 11 lacs.

Thus this results in a pay back of less than 2 months only.

VFD TO CONTROL THE WATER FLOW RATE WILL RESULT IN SAVING OF RS.

633600\MONTH

0

100

200

300

400

500

600

700

800

350 400 450 500 545

TR vs Flow rate

TR

29

4.5 TRANSFORMERS

The transformers at Hotel Leela are installed at basement and are naturally air

cooled. The secondary of the transformer is connected with the bus bar which

supplies to the main LT panel. As the bus bar and the LT panel are not accessible

the measurement of the output parameters has not been taken.

Observation

The ambient winding temperature of the transformer is 90° C. Where as the

observed average operating temperature is 109° C. At higher temperature, the

resistance of the winding increases which leads to higher copper losses and

consequently reduced efficiency. Move over, the sustained higher winding

temperature also deteriorates the insulation of the winding.

Assuming the temperature coefficient of the conductor at 0° C to be 0.004 per ° C,

the resistance of the winding at the average operating is 5.5% more than the

resistance at 90° C. This means 5.5% increase in the copper losses of the

transformer.

30

Table for Transformer Losses as per standards

KVA Rating No Load Losses in

W

Full Load Copper

losses at 75oC in

W

Efficiency %

100 500 2000 97.50

125 570 2350 97.66

160 670 2840 97.81

200 800 3400 97.90

250 950 4000 98.02

315 1150 4770 98.15

400 1380 5700 98.23

500 1660 6920 98.28

630 1780 8260 98.37

750 1800 9200 98.40

800 1900 9980 98.45

1000 2000 11880 98.54

1500 2100 15500 99.00

2000 2500 22000 99.00

2500 2800 26000 99.00

3200 3240 31050 99.00

Assuming the full load copper losses of each of the transformer is 16000 W.

This implies the losses due to increase in temperature is 16880 W. The following

calculations gives the monetary benefits of the operating the transformer at

ambient temperature.

31

Transformer copper losses

90 C̊ 109 C̊

Full load copper losses in W 16000.00 16880.00

Considering 80% loading 10240.00 10803.20

Annual losses in KWH 89702.40 94636.03

Total losses for 3 nos.

transformer 269107.20 283908.10

Losses in monetary terms (Rs

4.19/unit)

Rs. 1127559.17 1189574.92

Expected savings by operating

the transformer at ambient temp. 62015.75

EXPECTED SAVINGS BY OPERATING THE TRANSFORMER AT AMBIENT TEMP. IS

RS. 62015.75

4.6 COOLING WATER REQUIREMENT FOR DG SETS

One 1500 KVA DG set of Cummins require 1500 lpm of water for cooling in one

DG set at head of 15 mtr.

Thus total water required = 4500 lpm = 270 m3/hr

Now, desired flow of water should be gravitational flow from cooling tower to

heat exchangers as available head = 12 levels = 12 ft x 12 = 144 ft = approx 45 mtr

Pressure drop in a heat exchanger as per manufacturers data is 12 mtr. Thus a

pump with 20 mtr head potential with NPSH 45 mtr will successfully re-pump the

water to cooling tower after passing through the heat exchanger.

Power required by pump assuming pump efficiency of 80%

32

� " � ∆� � 1 � 2

3.6 � 105 � 6�270 � 20 �1000 � 9.81

3.6 � 105 � 0.8� 18.39 90

Thus the power required is 18.5 KW against running power of 45 KW.

Hence proper pump selection can save = 45 – 18.5

= 26.5 KW

Pump cost is approx. = Rs. 27,000/-

Savings assuming 4 hours of running everyday = 26.5 x 4 x 30 x Rs. 4.5 per unit =

Rs. 14,310/- per month.

Hence simple payback = <2 Months

PUMP OPTIMIZATION FOR DG SET COOLING WILL SAVE RS. 14310\MONTH

4.6 IMPROVEMENT IN EARTHING

The facility uses Cummins make DG sets for which quoted average of 3.8 to 4.2 is

easily achievable. We have observed an average of 3.51 which is on the lower

side. Monthly units generation is 9,00,000 KWH. Hence diesel consumed is

2,56,410 litres.

If this average is raised to 3.8 the diesel consumed will be 236842.

Thus a net saving of HSD by 19568 litres per month.

This is equivalent to INR 19568 x 34 = Rs. 665312 per month

This change can be brought by providing separate earthings for all earthing

points. At present the three earthing points of each DG are connected in one

place which on further moving gets connected to earthing strips of Electric Panels.

Similar is the case of Transformers.

The earthing pits provided are also not adequately spaced.

33

This causes the earthing currents to either keep circulating in the system or is

injected into the ground at various stages thus increasing heat losses. Due to this

a major amount of energy which is produced is not recorded in the meters and a

low average is recorded.

The tentative cost of providing 15 earthing pits @ Rs. 25000/- each = Rs,

3,75,000/-

Thus a Simple payback of 17 days is achievable. Hence the proposition is strongly

recommended.

IMPROVEMENT OF EARTHING OF TRANSFORMER AND GENERATORS WILL SAVE

RS. 665312 /MONTH

4.7 POWER FACTOR ANALYSIS

The above bar chart compares the average power factor of the facility for the

month of March and April. The power factor is satisfactory. But the

observation has been made that the capacitors have been installed at the main

0.989

0.993

0.987

0.988

0.989

0.990

0.991

0.992

0.993

Mar Apr

POWER FACTOR

34

LT panel, this ensures a good PF of the facility but the average PF of the local

panels is 0.845 as substantiated by the following tables.

The average PF of the HVAC panel is 0.845.With the replacement of the

capacitor the reduction in current with better PF (0.95) will be 72.43 A.

Thus total power reduction is �:.;<= > ?:@ > ;=.?< > A.B@

:AAA� 49.5 90

Thus daily savings = 49.5 x 20 = 990 KWH per day (assuming average 20

hours running each day) = 990 x 4.19 x 30 = INR 1,24,443 per month.

Here we do not have to invest in LT capacitors, we just need to shift some

capacitors from Transformer LT bus bar to various starters and MCC centres.

Tentative investment can be estimated to a maximum of Rs. 1,00,000/-

35

The average PF of the individual loads is 0.84. These lagging PFs are causing

local currents to flow in the LT distribution system of the facility.

Some of the assessable motors whose reading was taken during the audit are

given in the following table. The average PF of the observed motors is 0.81

which is under the permissible value. The range of the PF is 0.62 to 0.98.

Though the upper limit is good but the lower is not acceptable. Moreover

there are two motors running at PF less than 0.70.

36

Effects of Transmission & Distribution Losses Due Power Factor

Improvement:-

Transmission losses of plant + Distribution losses of plant = 3 % + 7 % = 10 %

(On total yearly Consumption)

The above Transmission and Distribution losses of plant are called plant

losses.

Transmission losses of plant are the losses occurring in main transformers,

H.T. Cables, Switch Gear etc. = 3 % (Of total yearly Consumption)

Distribution losses of plant are the losses occurring in main L.T. Cables, L.T.

Switch Gear, L.T. Bus -Bar etc. = 7 % (Of total yearly Consumption)

Now % loss reduction due to improvement of average P.F. from 0.94 to 0.99

Now Plant Copper losses in any A.C. System = I2 xR α 1

Cos ↓2

∴∴∴∴ Plant Copper losses = K

Cos ↓2

37

Now Plant copper losses at 0.94 P.F. �C

A.B? > A.B?

�C

A.DD<5

� 9 � 1.1317

Now Plant copper losses at 0.99 P.F . �C

A.BB > A.BB

� 9 � 1.0203

Thus Plant heat loss reduction by improving PF at consumption point

� �� E�� 0.94 F� G �� 0.99 F�

�� 0.94 F�

� 9 � H1.1317 G 1.0203I

9 � 1.1317

� 0.1114

1.1317

� 0.0984 ��! 10 %

Thus, by improvement in P.F. from 0.94 to 0.99, there will be a plant loss

reduction of 10 %. However the exact saving percentage can’t be calculated as

all motors are running at various PF varying form 0.7 – 0.9. But it is evident

that heat loss reduction is enormous and substantial, as per the example

calculation above.

* What are Transmission and Distribution losses of plant?

Transmission losses of plant are those electrical losses occurring in the

Transformers, H.T. Cables, and Switch Gears etc and which is standardized at

the rate of 3 % of the yearly energy consumptions of the Plant.

38

Distribution losses of plant are those electrical losses occurring in the L.T.

Cables, Fuse links, bus bars and Meters etc and which is standardized at the

rate of 7 % of the yearly energy consumptions of the plant.

∴Transmission losses of plant + Distribution losses of plant = 3 % + 7 % = 10

% (On yearly Consumption)

READJUSTMENT OF CAPACITORS WILL REDUCE THE TRANSMISSION AND

DISTRIBUTION LOSSES.

4.8 MOTOR EFFICIENCY AND LOADING

Two important attributes relating to efficiency of electricity use by A.C. Induction

motors are efficiency, defined as the ratio of the mechanical energy delivered at

the rotating shaft to the electrical energy input at its terminals, and power factor

(PF). Motors, like other inductive loads, are characterized by power factors less

than one. As a result, the total current draw needed to deliver the same real

power is higher than for a load characterized by a higher PF. An important effect

of operating with a PF less than one is that resistance losses in wiring upstream of

the motor will be higher, since these are proportional to the square of the

current. Thus, both a high value for efficiency and a PF close to unity are desired

for efficient overall operation in a plant.

The efficiency of a motor is determined by intrinsic losses that can be reduced

only by changes in motor design. Intrinsic losses are of two types: fixed losses -

independent of motor load, and variable losses - dependent on load. Fixed losses

consist of magnetic core losses and friction and windage losses. Variable losses

consist of resistance losses in the stator and in the rotor and miscellaneous stray

losses.

We have taken example of measurement of 10 HP motor for calculation of

efficiency.

Motor Specifications

Rated power = 7.5 kW/10 HP

39

Voltage = 415 Volt

Current = 17 Amps

Speed = 935 RPM

Connection = Delta

No load test Data

Voltage, V = 424 Volts

Current, I = 5.9 Amps

Frequency, F = 50 Hz

Stator phase resistance at 20 °C = 2.5 Ohms

No load power, Pnl = 156 Watts

( a) Let Iron Plus Friction and windage Loss , Pi + fw

No load Power Pnl – 156 Watt

Stator copper Loss, Pst @ 20o

C (Pst.Cu)

= 3 x (5.9/1.73) 2 x 2.5

= 87.23 Watt

Now Pi + fw = Pnl – Pst.cu = 156 – 87.23 = 68.77 Watt

(b) Stator Resistance at 120◦ C

K:=A � 2.5 � :=AL=<@

=A L =<@

� 3.48 MN��

(c) Stator Copper Losses at Full Load Pst.cu 120 0

C

= 3 x (17/1.73) 2 x 3.48

= 1008.32 Watt

(d) Full Load Slip = OPQR

H:STI�

H:AAASB<@I

:AAA

= 0.065

Thus, Input to Rotor = OPQR

H:STI

�;@AA

H:SA.A5@

40

�;@AA

A.B<@

= 8021.40

(e) Total Full Load Input Power

= 8021.40 + 1008.32 + 68.77 + 37.5 ( stray Losses 5 % of rated Output)

= 9135.99 Watt Say 9136 watt

(E) Motor efficiency at Full Load = UVWXYWX

UZ[YWX \ ]^^

= 82.09 % say 82 %

MOTOR LOADING

Most electric motors are designed to run at 50% to 100% of rated load. Maximum

efficiency is usually near 75% of rated load. Thus, a 10-horsepower (hp) motor has

an acceptable load range of 5 to 10 hp; peak efficiency is at 7.5 hp. A motor’s

efficiency tends to decrease dramatically below about 50% load. However, the

range of good efficiency varies with individual motors and tends to extend over a

broader range for larger motors, as shown in Figure motor is considered under

loaded when it is in the range where efficiency drops significantly with decreasing

load. Figure shows that power factor tends to drop off sooner, but less steeply

than efficiency, as load decreases. Overloaded motors can overheat and lose

efficiency.

41

The assessable motors of the facility were tasted and there loading and efficiency

has been calculated. The following table gives the detail of the HVAC electric

motors.

42

Table:

In the above observation table, there are three motors with overloading of up to

the maximum of 6% which is admissible. Motor B-2 is running at load of only

38.64% which is very low and leading to considerable energy losses at two

accounts, namely under loading and low efficiency. But, further investigation is

needed as the readings taken were momentary and therefore a load curve needs

to be drawn over a loading period to identify the saving opportunities.

In the above observation table, the loading and efficiency of three motors has

been calculated. Flushing motor pump is running at load of 50.67% and its

43

corresponding efficiency is 78.62%. The efficiency and loading of the other motors

has not been calculated as they were not assessable.

Above motors have total measured running load as 463.75 KW and average

efficiency of 83.6%.

Replacement of motors can bring the efficiency of 95% on running load thus

improving efficiency by 11.4% and subsequently reducing the load by 52.86 KW.

This will result in savings of 52.86 x 20 hrs per day x 30 days = 31716 KWH each

month = 31716 x 4.19 = INR 1,32,890 each month

Tentative investment of 410.88 KW = 410.88 x 2700 per KW = INR 11,09,382

Salvage Value of old motors = 400 x 463 KW = INR, 1,85,200

Thus net investment = 1109382 – 185200 = INR 9,24,182

Hence simple payback = 924182/132890 = 6.95 say 7 Months.

We recommend use of Baldor motors which are NEMA Premium efficiency range

motors and maintain very high efficiency even at 25% loading.

Replacement of old motors with NEMA Premium efficiency motors will save Rs

1,32,890/- per month resulting in payback of 7 months.

4.9 HARMONIC ANALYSIS

We have measured Harmonic Level in the plant and results are mentioned as

under.

44

Table – Harmonics measurements

Observations-

1. THD Levels in both Voltage and Current are under the permissible limits.

This is because of many VFD Drives in your system.

Hotel Leela LT Room PCC Board Electrical Parameters

S.

No. Name of PCC

Voltage Harmonics Current Harmonics

3rd 5th 7th THD 3rd 5th 7th THD

1 4-B HVAC-3 1600Amp 0.3 0.4 0.6 1.3 3.4 19 9.3 22

2 11-B HVAC-2 1600Amp 0 0.3 0.2 0.6 0 0.8 0.7 1.1

3 16B HVAC-3 1600Amp 0.3 0 0.2 0.7 0 4.2 1.2 4.7

45

4 9B Rising Main -1

1250Amp 0 0.2 0.3 0.6 5.8 0.8 4.6 2.7

5 10B Rising Main-2

1250Amp 0 0.3 0.3 0.5 6 21 1.2 9

6 14B Rising Main-3

2000Amp 0.3 0.2 0.2 0.7 8.5 3 1.6 11

7 15B Rising Main-4

2000Amp

8 1-B Laundry 630Amp 0.3 0.2 0.7 1.1 10 8.4 2.1 14

9 1-A Health Club, Business

Centre, Swimming Pool 1.2 0.4 0.8 1.5 6.4 2.8 1.9 8.2

10 2B Main Kitchen, Admin

Floor 0.2 0.5 0.8 1.5 5.6 4.1 0.9 8.5

11

8-C Plumbing 400Amp (Pump & Boiler room

Supply) 0 0.5 0.3 0.6 1.2 3.4 0.8 5.4

Observations-

1. THD Levels in Voltage are under permissible limits. Whereas Current THD

for 4-B HVAC-3, 10B Rising main-2, 14B Rising Main-3, 1-B Laundry are

above the permissible limits.

2. These higher THD Level create problems in system for example ACB tripping

without any fault flag, Burning of capacitors, Motor winding Bursting,

Frequent tripping of machinery on voltage fluctuation, and we advise to

install harmonic Filters in your Electrical network.

Leela Report 14 June

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