HVAC

C 21.10.04 sd sd sdABP PSG TPL

B 15.10.04 FOR INFORMATION sd sd sdABP PSG TPL

A 13.10.04 FOR INTERNAL REVIEW sd sd sdABP PSG TPL

REV. NO. DATE DESCRIPTION REVD. BY CHKD. BY APPD. BYProject Name : PP7 EXTENSION 3 PROJECT

Owner : SAUDI ELECTRICITY COMPANY - CENTRAL REGION BRANCH

Contractor : SIEMENS POWER GENERATION

Subcontractor : ARABIAN BEMCO CONTRACTING CO.TITLE : NAME DATE

PREPARED BY ABP 18.09.04CHECKED BY PSG 13.10.04APPROVED BY TPL 13.10.04SCALE : N.T.S

DOC No. SHEET NO. REV. NO.SAR687- XW01- 00SA- B22225 COVER + 6 + 16 PAGES C

MANUFACTURER'S DRAWING NO. PROJECT CODE CAD FILE SCALEN.T.S

REVISED AND RE-ISSUED FOR INFORMATION

HEAT LOAD CALCULATIONHVAC SYSTEM

FOR ELECTRICAL BUILDING

PP7 EXTENSION 3 PROJECTHEAT LOAD CALCULATION- HVAC SYSTEM

FOR ELECTRICAL BUILDING

TABLE OF CONTENTS

Table of Content 1

1. Purpose 2

2. Design Basis & Assumption 2

3. Reference 3

4. Attachment 3

5. Computation 3

6. Result & Conclusion 6

PP7 Extension 3 Project - Units 23 & 24 SAR687- XW01- 00SA- B22225 Sheet REV CHEAT LOAD CALCULATION - HVAC SYSTEM 1

1 PURPOSE1.1

1.1.1 To work out the total cooling coil load 1.1.2 To work out the sensible cooling coil load 1.1.3 To work out the air flow required1.1.4 To work out the cooled entering air temperature ( DB/ WB)1.1.5 To work out the leaving air temperature ( DB/ WB)1.1.6 To work out the heating coil capacity

1.2 To perform the air extaction system calculation for the Battery room in the electrical building as follows:1.2.1 To work out capacity of exhaust fans1.2.2 To work out the quantity of exhaust fans

1.3 To perform the pressurisation calculation for the Electrical Building as follows:1.3.1 To work out capacity of pressurisation fans1.3.2 To work out the quantity of pressurisation fans

2 DESIGN BASIS & ASSUMPTION

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.82.9

2.1

2.11

2.12

2.13


To find out the Air Conditiong Heating & Cooling Load for the Electrical building as follows:

As per HVAC system-design criteria , 2x 100% capacity Mini- Split Air conditioning system (Terminal Split Fan Coil unit) shall be provided for the MV/LV Switchgear Room ( Electrical Building- 00UBA).

As per HVAC system-design criteria and specification cl. No 1.2.0.0, we have considered out door design conditions as design maximum dry bulb temperature as 55 0C, average wet bulb temperature as 21 0C & design minimum temperature as -5 0C. As per HVAC system-design criteria and specification cl. No 4.4.10.0, we have considered indoor design conditions as summer dry bulb temperature as 27 0C, Relative Humidity as 50+5 % & winter dry bulb temperature as 24 0C and relative humidity as 45%..

As per HVAC system-design criteria, the minimum fresh air requirement of 15 CFM/ person has been considered. Roof & Walls U- Values have been calculated based on composition as per details provided at Attachment 4.2 Total three (3) nos. of occupants have been considered in the Electrical building. Occupant sensible load of 245 BTU/hr/ person and latent 205 BTU/hr/ person have been considered.For performing HVAC heat load calculation, electrical heat dissipation load of 20,000 watts have been assumed in the electrical rrom and used in the calculation. However, the same will be updated later based on the finalised vendor equipment load data.

Lighting load for Electrical room has been considered 1.5 watts/ sqft. based on ASHRAE guide line.

As per HVAC system-design criteria, the battery room exhaust fan shall be designed considering 7 air changes/ hour. Supply air in to the battery room will be taken from the adjacent electrical room via transfer grilles. 2x 100 % exhaust fans have been provided for this purpose.As per SEC specification clause no. 4.4.10.0, the room must be maintained at permanent +ve pressure. The indoor air conditioned spaces of the Electrical Building shall be pressurized to maintain positive pressure of 15 Pa with respect to outside atmosphere, as per Design Criteria. The electrical room pressurisation fan has been designed to provide the fresh air requirement inside the room, to maintain the positive pressure as well as to cater to the battery room supply air quantity. As per HVAC- Design criteria, 2 x 100% pressurisation fans has been provided for this purpose.The pressurization calculation shall be based on Bernoulli equation for pressure loss as per ASHRAE Handbook - Fundamentals. Ref. Attachment- 4.7In order to calculate the pressurisation air quantity, it is assumed that All doors are of steel and well gasketed and all duct slab openings (if any) are made airtight.

2.14

2.15

3. Reference

3.1 Design Criteria - HVAC system Doc. No.: SAR687-XU00-00SA-B20700 Rev-B. 3.2 Flow diagram- HVAC System (Doc No : SAR687-XG07-00SA-B21700, Rev-B)3.3 Plan View Level (+) 2.00M Electrical Building, Basic Building Plan Drawing (No: SAR687-VF00-00UBA-B10202 Rev-A3.4 ASHRAE FUNDAMENTALS- 2001

4. Attachment The computerised Air conditioning heat load calaculation comprising of the followings:

4.1 Air Conditioning System Summary Sheet (Manually consolidated)- 1 page4.2 U- Value calculation (Manually consolidated)- 2 pages4.3 Design weather parameters (1 page)- program printout4.4 Space input data ( 2 pages)- program printout4.5 Air System Input data (2 pages)- program printout4.6 Air System sizing summary details ( 5 pages)- program printout4.7 Bernoulli equation for pressure loss/ Pressurization calculation (3 pages)

5. Computation

5.1 Air Conditioning (AC) System:

a Ref. 4.3

b

c Ref. 4.5

d Ref. 4.6

e Ref. 4.1

5.2 Air Extraction System Calculation for Battery Room:5.2.1 Assumptions/ Input Data

a Battery Room -Length L m 7.50 Ref. 3.3b Battery Room- Width W m 4.00 Ref. 3.3c Battery Room- Height H m 3.60 Ref. 3.3d Total room volume (V= LxWxH) V m3 108.00e Air Change Rate ( per Hour) ACH 7.0 Ref.2.12

5.2.2 Pressurization Air Quantity:a m3/hr 756.0

b m3/hr 756.0

5.2.3 Exhaust Fan sizing :a Total exhaust air quantity m3/hr 756.0 Ref.5.2.2-b

b No. 1 ref.: 2.10

PP7 Extension 3 Project - Units 23 & 24 SAR687- XW01- 00SA- B22225 Sheet REV C

We will consider air leakage through doors and wall openings only to calculate the quantity of pressurized air requrement. 1 mm air gap around the doors and 1 mm gap around the wall opening has been considered for the purpose.

Electrical switchgear room shall have split terminal unit type Air Conditioner and hence no AC duct opening are required on the walls.

The AC system heat load calaculation have been performed based on ASHRAE guide line, using Carrier E-20-II Hourly Analysis Program. The computerised AC heat load calaculation comprises the followings:Design weather parameters : The weather input data for the project location, has been attached at Attachement 4.3Space input data : All the input parameters for performing the AC heat load calculation in the Electrical building (SPACE) have been provided at Attachment 4.4. For details of U- value calculation, refer Attachment 4.2

Ref. 4.4 & 4.2

Air System Input data : Air system input data ( type of system, equipment considered,inside set conditions etc. ) have been provided at Attachment- 4.5

Air System sizing summary details : Based on the above input data, the summary details have been provided at Attachment- 4.6In addition to above, mannually consolidated Air Conditioning System Summary Sheet have been prepared for handy reference and have been provided at Attachment- 4.1

Required ventilation air quantity (5.2.1- d x 5.2.1-e)Total exhaust air quantity (same as 5.2.2-a)

No. of exhaust fans proposed- working

HEAT LOAD CALCULATION - HVAC SYSTEMSAR687- XW01- 00SA- B22225

3REV C

c m3/hr 756.0

i.e. cfm 440.0d No. of stand by fan proposed No. 1 ref.: 2.10e Nos. 2

5.3

5.3.1 Air Velocity Calculation:a P= 1/2 K p V2 Ref. 4.7

Where, P= Pressure Loss (Pa)p= Air Density (kg/m3)K= Wind Pressure Coefficient V= Air Speed in m/s

Inddor Outdoor

P inside - P outside = Pressure diff. to be maintainedPi - Po = 15 Pa

friction loss @ inlet Afriction loss @ inlet B

Pi - Po =b 0.35 Ref. 4.7

c 0.85 Ref. 4.7

d Air Density kg/m3 p= 1.2e Air Velocity Calculation: Pi - Po =

=

= 0.72 x V2i.e. 15= 0.72 x V2

V= 4.56 m/s5.3.2 Pressurization Air Quantity required due to door opening:

a Ref.:3.3

Width m 1.5Height m 2.4

No. of Doors No. 1.0

b

Width m 2.8Height m 2.6

No. of Doors No. 1.0

Capacity of exhaust air fan ( 5.2.3-a/ 5.2.3-b)

Total no. of exhaust fans proposed (5.2.3-b + 5.2.3-d)Pressurisation System for Electrical Room:

The wind pressure is given by Bernoulli equation :

1 mm air gap

PA = 1/2 KA p V2

PB = 1/2 KB p V2

PA + PB

We use averaged wall pressure co-efficient for Indoor walls (internal wall pressure co-efficient)

KA =

We use averaged wall pressure co-efficient for outdoor walls

KB =

1/2 KA p V2 + 1/2 KB p V2

½ x 0.35 x 1.2 x V2 + ½ x 0.85 x 1.2 x V2

Size of Door- (From Platform to Electrical room)

Size of Door- (From Electrical Room to Equip loading Plat Form)

AA

BBA


c m 18.60

d mm 1.0 ref.: 2.15

e m2

m2 0.0186

f m3/sec Area x air velocity

m3/sec 0.08

I.e. l/s 84.9I.e. cfm 180.0

5.3.3

a Ref. 2.16

b cfm 0.00

5.3.4

a cfm 180.0

~say cfm 180.05.3.5 Pressurisation Fan sizing:

a cfm 180.0 ref.: 5.3.4-a

b cfm 440.0 ref.: 5.2.3-c

c cfm 620.0

d Nos. 1 ref.: 2.12

e Nos. 1 ref.: 2.12

f Total no. of pressurisation fans Nos. 2

Total perimeter of doors at 5.3.2-a & b above

Air gap considered for pressurisation calculation

Total area of doors to be considered for pressurisation calculation

Air gap x total perimeter of doors

Pressurisation air flow required due to door opening ( 5.3.2-e x 5.3.1 -e)

Pressurization Air Quantity required due to duct openingSize of duct opening in the electrical building.

No duct opening in the electrical building.

Pressurization Air Quantity required due to duct openingTotal Pressurization Air Quantity required :Total Pressurization Air Quantity required ( 5.3.2-f +5.3.3-b)

Total Pressurization Air Quantity required Toatl exhaust air from battery room ( =capacity of 1x100% exhaust air fan)Total air to be supplied by the pressurisation fanNo. of pressurisation fan proposed (working)No. of pressurisation fan proposed (standby)

6.0 RESULT & CONCLUSION

6.1

6.1.1 Total cooling coil load = 186.5 MBH Ref. 4.1

i.e. (15.5) TR

6.1.2 Total sensible cooling coil load = 155.5 MBH Ref. 4.1

i.e. (13.0) TR

6.1.3 Total air flow required = 7340 cfm Ref. 4.1

6.1.4 Entering air temperature ( Dry bulb/ Wet bulb) = 88.0/ 56.1 Ref. 4.1

6.1.5 Entering air temperature ( Dry bulb/ Wet bulb) = 62.7/45.6 Ref. 4.1

6.1.6 Total Heating coil capacity = 19.9 MBH Ref. 4.1

i.e. (1.7) TR

6.2 Air Extraction System (Battery Room):6.2.1 Capacity of exhaust fans- each = 440 cfm Ref 5.2.3-c

6.2.2 No. of exhaust fans working = 1 Nos. Ref 5.2.3-b

6.2.3 Total no. of exhaust fans = 2 Nos. Ref 5.2.3-e

6.3 Pressurisation system (Electrical Room): 6.3.1 Capacity of pressurisation fans- each = 620 cfm Ref 5.3.5-c6.3.2 No. of pressurisation fans working = 1 Nos. Ref 5.3.5-d6.3.3 Total no. of pressurisation fans = 2 Nos. Ref 5.3.5-f

PP7 Extension 3 Project - Units 23 & 24 SAR687- XW01- 00SA- B22225 Sheet REV C

Air Conditioning System ( Also refer Attachment 4.1):

0F

0F

HEAT LOAD CALCULATION - HVAC SYSTEMSAR687- XW01- 00SA- B22225

6REV C

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