JAKARTA GREEN BUILDING USER GUIDE VOL. 2 AIR ...greenbuilding.jakarta.go.id/files/userguides/Vol-2-Air...2 AIR CONDITIONING & VENTILATION SYSTEM Air Conditioning, Air Quality, and

JAKARTA GREEN BUILDING USER GUIDE

VOL. 2

AIRCONDITIONING& VENTILATION SYSTEM

The Government of the Province ofJakarta Capital Special Territory

In cooperation with: IFC in partnership with:

C O D E R E Q U I R E M E N T S

Air Conditioning (AC) AC01 Temperature Setpoint AC02 Minimum Cooling System Efficiency AC03 VAV for central cooling system AC04 VSD for pump and fan motors AC05 Minimum chilled water pipe insulation

Ventilation System (VS) VS01 Minimum ventilation rate

Air Quality in Spaces (AQ) AQ01 CO2 sensor control AQ02 CO control in enclosed parking AQ03 CFC-free refrigerants

The calculation should be done using the calculator

available on this website

http://greenbuilding.web.id

Checklist for all code requirements lists the required

documents is also available on this website

http://greenbuilding.web.id

C O D E R E Q U I R E M E N T

C O D E R E Q U I R E M E N T D E T A I L S

01

02

INTRODUCTION 2

7

23

6

23

24

25

26

27

27

29

31

32

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JAKARTA GREEN BUILDING USER GUIDE

VOL. 2

table of contents

AIR CONDITIONING & VENTILATION SYSTEM

O T H E R G O O D P R A C T I C E S03Reducing Cooling Load

Commissioning

Thermal Zoning

Absorption Chillers

Magnetic Drive on Compressors

Chiller Sizing

Maintenance

Building Automation System

Piping and Ducting

Cooling Tower Design and Operation

Natural Ventilation

Energy Recovery

Maintenance

Ceiling Fans

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Air Conditioning, Air Quality, and Ventilation:An Introduction

Most modern buildings are designed to be completely or mostly enclosed, shielding its occupants from direct contact with the outside environment. Air-conditioning systems are used to provide comfortable indoor thermal conditions. This is in contrast to the traditional architecture of Indonesia, which relied heavily on shading the indoors from the harsh sun, while allowing breeze to flow freely through the building.

In Jakarta’s tropical climate, thermal comfort is primarily provided by

cooling indoor temperature, lowering humidity levels in the air being

supplied to the space, and ensuring the cleanness of the supply air.

“Comfortable” conditions as defined by standards for Jakarta include

indoor temperature of 25oC and 54% to 66% relative humidity. As Figures 1 and 2 show, the Jakarta outdoor conditions are mostly above these

values, requiring mechanical cooling and dehumidification. This results in

significantly high need for air-conditioning throughout the year.

Average Jakarta Outdoor Temperature vs.

Recommended Indoor Temperature

F I G U R E . 0 1

Average Minimum Temperature

Average Maximum Temperature

Recommended Indoor Temperature

AJr

Tem

per

atu

re (

oC

)

20

24

28

32

22

26

30

34

Jan May SeptMar Jul NovFeb Jun OctApr Aug Dec

Period when outdoor temperature ishigher than indoor

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A study of multiple Jakarta buildings (Figure 3 below) shows air-

conditioning to be the highest energy consuming end-use among all the

studied building types.

Energy modeling studies and numerous real life examples also indicate that

energy efficiency measures related to air-conditioning offer some of the

best energy saving opportunities with very reasonable paybacks.

Due to these reasons, the new Jakarta Green Building code puts a lot

of emphasis on reducing air-conditioning load and increasing its system

efficiencies.

It is estimated that about 1.37 million metric tons of CO2e emissions can

be reduced by 2030 if all the large new buildings in Jakarta follow the

efficiency improvements mandated in the new Green Building code2.

Average Jakarta outdoor Relative Humidity vs.

Recommended indoor Relative Humidity

F I G U R E . 0 2

Outdoor Relative Humidity

Recommended Indoor Relative Humidity R

elat

ive

Hu

mid

ity

(%)

40

50

60

70

85

45

55

65

80

75

90

Jan May SeptMar Jul NovFeb Jun OctApr Aug Dec

Period when outdoor Relative Humidity ishigher than indoor

Building Energy Use Breakup for Multiple

Jakarta buildings1

F I G U R E . 0 3

Bu

ild

ing

En

erg

y U

se (

%)

Hotel Shopping MallHospital Government Office Office Building

Air Conditioning

Elevator

Others

Lighting + outlet

0

40

80

20

60

100

65% 57% 57%47%55%

1 Japan International Cooperation Agency (JICA) Electric Power Development, 2009.2 IFC sensitivity analysis for Jakarta Green Building Regulations, 2011.

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Supplying fresh outside air and removal of stale indoor air from inside the building or “ventilation” is an important element of air conditioning systems. The word “ventilation” is derived from Latin word ventus, meaning “wind.” Ventilation may be provided mechanically through fans or naturally through flow of air from windows and other openings. It is one of the most important factors for maintaining healthy indoor air quality and occupant comfort in a building as it replenishes oxygen and removes moisture, odors, smoke, heat, and airborne bacteria.

Increasing ventilation rates to acceptable levels has shown a positive impact

on occupant health and productivity in many studies. Acceptable ventilation

rates vary with occupancy, activity and contaminant levels in the space. The

productivity improvement shown by these studies ranges from 0.62% to

7.3%. In some cases the value of even a small increase in productivity far

outweighs the additional cost of providing high ventilation rates3.

3 Lawrence Berkeley National Laboratory. Indoor Air Quality Scientific Findings Resource Bank. Health and Economic Impacts of Building Ventilation. (http://www.iaqscience.lbl.gov/vent-summary.html)

4 Lawrence Berkeley National Laboratory. Home Interview of IAQ Acknowledgement. Indoor Air Quality Scientific Findings Resource Bank. (http://www.iaqscience.lbl.gov/vent-summary.html)

Individually Controlled Ventilation System

Increase Outdoor Ventilation Rate

Improve Filteration

Provide Task Air

Remove Pollutants

Improved Air Quality Increases Individual

Productivity4

% I

mp

rove

d I

nd

ivid

ual

Pro

du

ctiv

ity

Menzies 1997

0

1

6

2

8

3

10

12

14

Wargocki 1998

Wargocki 2000

Sundell 1998

Brundage 1998

Milton 2000

Fisk & Rosenfeld 1997B

Fisk 1991 AHall 1991

Fitzner 1955

Fisk 1991 B

EPA 1989

Rosen 1999

Lagercrantz 2000

Jakkoia 1995

F I G U R E . 4

11

3.25*

1.1*

n=

73,

p<

0.00

1

n=

30

n=

30,

p<

0.02

n=

399

n=

210

n=

3720

n=

2764

7.37**

0.99**

1.7

0.76** 0.76**

1.36**

0.8**

0.53** 0.48**

1.65**

0.7**0.62**

a

b cd f j

l

ik

h

g

e

a. 8.5 % improvement in typing.b. Typing, addition proof reading and creative

thinking.c. 33 % reduction in SBS.d. 2 workdays lost from ARD.e. 2 % production lost from SBS.f. 35 % reduction in short term sick leave.

g. 45 % improvement in ventilation effectiveness.

h. 2 workdays loss from mucosa symp.i. 20 % reduction from pollutant.j. 17.8 % improvement in ventilation

effectivenessk. 3 % self-reported production loss.l. 55 % reduced non-attendance.

* Performance improvement for special tasks multiplied by estimated time at task.** Improved ventilation effectiveness calculated relative to productiivity gains from other studies.

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Increasing the mechanical ventilation rates requires running fans at higher

speeds or for longer periods. Additionally, if the outdoor air being brought

in is warmer and more humid than desired, energy is used to cool and

dehumidify it. This can increase the energy use of the air conditioning

and ventilation systems. Therefore, careful optimization of the ventilation

rate should be done to avoid energy penalties. A well designed ventilation

system provides adequate ventilation while limiting energy use and

avoiding occupant discomfort.

The importance of ventilation is highlighted in the “Jakarta Special Capital Region Province Governor Regulation Number 54 year of 2008 on Indoor Air Quality Standard (KUDR)”, which lists the indoor air

quality standard for various building types.

Occupied indoor spaces, that are not ventilated well, can have an

accumulation of Carbon Dioxide (CO2) that is detrimental to human health.

The new code addresses this by requiring automatic control of ventilation

in high-occupancy spaces. Similar controls in enclosed parking spaces are

also required to prevent buildup of carbon monoxide from vehicle exhaust.

• Loftness, Vivian FAIA, Hartkopf, Volker, Ph.D., Gurtekin, Beran, Ph.D., Hansen, David, Hitchcock, Robert Ph.D., U.S. DOE, Lawrence Berkeley National Laboratory.

• Advanced Building Systems Integration Consortium (ABSIC), Linking Energy to Health and Productivity in the Built Environment. Evaluating the Cost-Benefits of High Performance Building and Community Design for Sustainability, Health, and Productivity. (http://www.usgbc.org/Docs/Archive/MediaArchive/207_Loftness_PA876.pdf)

• Olesen W. Bjarne. Indoor Environment - Health - Comfort and Productivity. (http://www.ashrae.org.sg/Olesen-Health-comfort-productivity.pdf)

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01 code requirement

1

2

3

4

5

6

7

8

9

AC01 - Minimum 25oC and relative humidity 60%±10%

for conditioned and occupied spaces.

AC02 - Minimum cooling system efficiency as per SNI

6390-2011.

AC03 - Variable Air Volume (VAV) for centrally cooled

systems.

AC04 - Variable Speed Drives (VSD) for chilled water

pumps and cooling tower fans.

AC05 - Chilled water pipe insulation as per SNI 03-6390

2011.

VS01 - Minimum ventilation rates per Section 4.4 of

SNI 03-6572 2001.

AQ01 - CO2 control of outside air in some spaces.

AQ02 - CO control of ventilation in enclosed parking.

AQ03 - Chiller refrigerant to be free of Chloro Fluoro

Carbons (CFC).

R E F E R R I N G T O A R T I C L E 8

R E F E R R I N G T O A R T I C L E 9

R E F E R R I N G T O A R T I C L E 1 8

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02code requirement details

Mechanical system for occupied spaces should be designed to maintain a minimum 25oC (twenty-five) and relative humidity 60% ± 10% (i.e. between 54% and 66%). This requirement applies to occupied and air-conditioned spaces only.

C O D E R E Q U I R E M E N T 1

Typical indoor temperature set points in Jakarta range from 22-26oC,

although thermostat setting in some public spaces as low as 20oC have

been observed. Such low set points are quite common in Jakarta’s malls,

high-end hotels, and offices.

Energy simulation studies by IFC show that increasing the average set

point temperature by 2oC can save up to 11% of the total energy use in

typical Jakarta buildings.

Since human comfort depends on wind speeds along with the space

temperature, ceiling fans can maintain acceptable comfort conditions

even if the space temperatures are increased. It has been shown through

multiple studies that most occupants accept higher temperatures when

they are subjected to a breeze.

Ceiling fans have been a very effective means of increasing air circulation

and velocity for over a century. However, many new air conditioned

buildings in Jakarta do not have ceiling fans and completely depend on

the air conditioning system for air circulation. Ceiling fans can be a very

effective means of energy conservation especially in tropical climates like

Jakarta, where the humidity levels are relatively high.

I M P A C T

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Simulation studies have demonstrated that in the American tropical state of Florida, using ceiling fans combined with raising a home’s temperature by 1oC will generate about 14% net savings in annual cooling energy use (subtracting out the ceiling fan energy and accounting for internally released heat).5

Several governments have set temperature set point policies for buildings. Hong Kong government encourages a setting of 25.5oC during summers6. Taipei (Taiwan) recently passed a statute requiring all buildings to maintain the temperature above 26oC.

Japanese Ministry of Environment (MOE) has gone even further and recommended that indoor temperatures be set at 28oC as part of its “Cool Biz” campaign. This campaign was initiated due to power scarcity in the country and accelerated recently due to the Fukushima nuclear disaster and the resulting nuclear power plant closures. All Japanese government departments, businesses and the general public were asked to pre-set their office and home air conditioners to 28oC (82oF) throughout the cooling season until September. On its face, the request seemed simple, but in Japanese culture it is socially unacceptable to show up for work in anything but business attire. Encouraging people to “dress down” and wear cool and comfortable clothes to work, therefore, was a main focus of the campaign. In a 2009 nationwide poll conducted by the Japanese Cabinet Office, 57% of 2,000 survey respondents reported that Cool Biz had been implemented in their workplaces. In the region served by Tokyo Electric Power Company (TEPCO), there was an approx. 11.8% reduction (temperature adjusted) in electric power usage in households during summer 2011 (July and August) compared with the preceding year, avoiding any blackouts and brownouts.7

5 James, Patrick W, Sonne, Jeffrey K, Vieira, Robin K, Parker, Danny S, Anello, Michael T. Are Energy Savings Due to Ceiling Fans Just Hot Air? (http://www.fsec.ucf.edu/en/publications/html/FSEC-PF-306-96/)

6 Electrical and Mechanical Service Department. (http://www.epd.gov.hk/epd/english/environmentinhk/conservation/files/25.5.pdf)

7 Tools of Change. Cool Biz, Japan. (http://www.toolsofchange.com/en/case-studies/detail/662/)

More information on impact of increasing cooling temperature set points can be found in these documents:• Miller, Wendy; Kennedy Rosemary; Loh, Susan. Benefits and

Impacts of Adjusting Cooling Set points in Brisbane - How office workers responded. (http://eprints.qut.edu.au/55120/1/Miller_Kennedy_and_Loh_Jan012.pdf)

• British Council for Offices. 2008. 24°C Study Comfort Productivity and Energy Consumption. (http://www.bco.org.uk/uploaded/24_Degrees_Full_Report_FEB_8.pdf)

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8 SNI 6390-2011.9 IFC sensitivity analysis for Jakarta Green Building Regulations.

All cooling systems are required to have a minimum efficiency according to following table from SNI 6390-2011. Please note that these are full load efficiencies.


T A B L E . 0 1

R E F R I G E R A T I O N M A C H I N E T Y P E S

M I N I M U M E F F I C I E N C Y

COP KW/TR

Split < 65.000 BTU/h

Variable Refrigerant Value

Split Duct

Air Cooled Chiller < 150 TR (recip)

Air Cooled Chiller < 150 TR (screw)

Air Cooled Chiller > 150 TR (recip)

Air Cooled Chiller > 150 TR (screw)

Water Cooled Chiller < 150 TR (recip)

Water Cooled Chiller < 150 TR (screw)

Water Cooled Chiller > 150 TR (recip)

Water Cooled Chiller > 150 TR (screw)

Water Cooled Chiller > 300 TR (centrifugal)

2.70

3.70

2.60

2.80

2.90

2.80

3.00

4.00

4.10

4.26

4.40

6.05

1.303

0.951

1.353

1.256

1.213

1.256

1.172

0.879

0.858

0.826

0.799

0.581

Minimum Efficiency of Electric Cooling Equipment8

Since cooling is the single largest energy use in most buildings in

Jakarta, cooling efficiency improvements provide excellent energy saving

opportunities.

I M P A C T

Energy Saving Potential due to Increased Cooling

System Efficiency9

F I G U R E . 0 5

To

tal

En

erg

y S

avin

gs

(%)

Hotel RetailHospitalOffice School Apartment0

4

8

2

6

12

10

10.1%

5.3% 5.5%

3.7%

4.9%

3.6%

10

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According to a research paper by the US Lawrence Berkeley National

Laboratory (LBNL), Indonesia’s residential air conditioning energy

consumption is projected to increase almost three fold by 2030 as

compared to 2005. In order to control the resultant energy consumption

increase, the efficiencies need to increase in a similar proportion10.

A similar dominance of growth over efficiency has prevailed in the United

States. From 1993 to 2005, energy efficiency of air-conditioning equipment

improved by almost 30 percent, but household energy consumption for air

conditioning still doubled during this period11.

The current efficiency requirements are fairly lenient as compared to

most international standards and codes, in order to make it easy and

cost effective for the industry to implement. Future versions of the code

are planned to have efficiency requirements that match international

standards and also provide higher energy savings. Some typical efficiencies

recommended by ASHRAE 90.1- 2010 are listed below.

T A B L E . 0 2

E Q U I P M E N T T Y P E SIZE(tons)

MINUMUM EFFICIENCY

(COP)

Air cooled - split and single package

Air cooled - split system

Air cooled - single package

Water cooled - sply and single package

Air cooled - package and split

Air cooled with condenser

Water cooled

Water cooled

Water cooled

Water cooled

5.42 - 11.25

< 5.42

< 5.42

< 5.42

> 20

< 150

< 75

75 - 100

150 - 300

> 300

3.28

3.81

3.81

3.55

2.78

2.80

4.51

4.54

5.17

5.67

Recommended Cooling System Efficiencies12

10 McNeil, Michael A; Letschert, Virginie E - Environmental Energy Technologies Division, Lawrence Barkeley National Laboratory. Future Air Conditioning Energy Consumption in Developing Countries and what can be done about it: The Potential of Efficiency in the Residential Sector. (http://escholarship.org/uc/item/64f9r6wr)

11 Cox, Stan. Cooling a Warming Planet: A Global Air Conditioning Surge. (http://e360.yale.edu/feature/cooling_a_warming_planet_a_global_air_conditioning_surge/2550/)

12 ASHRAE 90.1- 2010.

More information on designing cooling systems is available in following documents:• Energy Design Resources. 2009. Chilled Water Plant Design Guide.

(http://www.taylor-engineering.com/downloads/cooltools/EDR_DesignGuidelines_CoolToolsChilledWater.pdf)

• McQuay International. 2001. Application Guide - Chiller Plant Design. (http://www.mcquay.ru/downloads/wsc%20design.pdf)

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13 IFC sensitivity analysis for Jakarta Green Building Regulations.14 Energy Efficiency Manual by Donald Wulfinghoff.

For centrally cooled systems, a Variable Air Volume (VAV) system should be used.


Variable Air Volume systems can between 1% and 2% operational energy

for typical buildings in Jakarta, as shown in the following figure.

In a Variable Air Volume (VAV) air handling system, space cooling is

controlled by varying the supply air flow while the supply air temperature

is kept constant. The system tailors the output of the fan precisely as the

load changes. While a VAV system is rare in single zone systems, it is

common and more likely to be economical in large fan systems14.

VAV systems are efficient because they provide fan energy savings that

constant volume systems cannot. Typically fans consume more energy in

a HVAC system than the compressors.

In a VAV system, each building zone is equipped with a VAV terminal. The

terminal controls vary the internal damper position to provide just the right

volume of air to match the zone cooling load.

It is recommended that fans in parallel VAV fan-powered boxes be sized

for 50% of the peak design flow rate. Minimum volume set points for fan-

powered boxes should be equal to 30% of peak design flow rate or the

rate required to meet the minimum outdoor air ventilation requirement,

whichever is larger.

I M P A C T

Energy Savings due to VAV13

F I G U R E . 0 6T

ota

l E

ner

gy

Sav

ing

s (%

)

HotelRetail HospitalOffice0.0

1.0

0.5

1.5

2.0

1.7%1.6%

1.4%

1.0%

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For further information on VAV systems, please refer to the following documents:• Davis, Gray. California Energy Commission. 2003. Design

Guideline - Advanced Variable Air Volume System Design Guide. (http://www.energy.ca.gov/2003publications/CEC-500-2003-082/CEC-500-2003-082-A-11.PDF)

• Energy Design Resources. 2009. Advanced Variable Air Volume VAV System Design Guide. (http://www.energydesignresources.com/media/2651/EDR_DesignGuidelines_VAV.pdf)

• Energy Star Building Manual. 2008. Air Distribution System. (http://www.energystar.gov/ia/business/EPA_BUM_CH8_AirDistSystems.pdf?b50f-779d)

Provide Variable Speed Drives for primary loop chilled water pumps and cooling tower fans.


Variable Speed Drives (VSD) can provide savings on the pump and fan

energy at a reasonably low cost.

A Variable Speed Drive (VSD) allows the motor speed to be controlled to

match the need of the load it serves, rather than running at full speed at

all times. Installing a VSD on the primary chilled water pumps will allow

the speed of the pumps to be varied in response to changes in the cooling

loads and chilled water system temperature differentials. VSDs are also

known as Variable Frequency Drives (VFDs).

I M P A C T

Energy Savings due to VSDs on Cooling Towers in Typical Jakarta Buildings15

F I G U R E . 0 7

To

tal

En

erg

y S

avin

gs

(%)

HospitalHotel RetailOffice

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

2.6%

4.7%

3.4%3.1%

15 IFC sensitivity analysis for Jakarta Green Building Regulations.

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Besides saving energy consumption, VSDs also provide:

• Closecontrolofleavingwatertemperaturebacktocondenser

• Softstarts,reducingstressonfandrivesystem

• Soundcontrol

• Builtindiagnosticandcontrolcapabilities

More information on VSDs is available in these documents:• Honeywell. Variable Frequency Drive (VFD) - Application Guide.

(http://www.kele.com/Catalog/13%20Motor%20Controls/PDFs/Honeywell%20VFD%20Application%20Guide.pdf)

• Hydraulic Institute; Europump; U.S. Department of Energy’s Industrial Technologies Program. Variable Speed Pumping - A Guide to Successful Applications, Executive Summary. (https://www1.eere.energy.gov/manufacturing/tech_deployment/pdfs/variable_speed_pumping.pdf)

Since the power demand of the primary chilled water pump motor scales

approximately to the 2.5 power with speed, reducing the pump speed to

70% when the chiller load is around 70% will result in a primary chilled

water pump energy savings of approximately 55% to 60%. At low loads,

reducing the pump speed to 50% will result in a primary chilled water

pump energy savings of approximately 80%. Since the chillers operate

mostly below 70% of their design cooling capacity, the energy savings

can be substantial.

16 Carbon Trust -Making Business Sense of Climate Change. Variable Speed Drives, Introducing Energy Saving Opportunities for Business. (http://www.energylab.es/fotos/081105155611_5gf9.pdf)

Typical Power Saved Using a VSD for Pumps16

F I G U R E . 0 8

Fixed Speed Power Input

Power Input to Drive

Power Saved

Po

wer

(%

)

Flow (%)

0

50

20

70

10

60

30

80

40

90

100

0 5020 7010 6030 8040 90 100

Power Saved

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Provide chilled water pipe and refrigerant pipe insulation per the following table taken from SNI-0306572 as specified in Article 8.3.


T A B L E . 0 3

P I P E S Y S T E M

F L U I DT E M P E R A T U R E(oC)

M I N I M U M I N S U L A T I O N T H I C K N E S S F O R T H E P I P E S I Z E (mm)

TYPE ≤50mm <25mm >200mm31-50mm

Chilled Water

Refrigerant

4.5 - 13

< 4.5

12

25

25

38

20

38

12

25

Minimum Insulation for Chilled Water Piping17

1. If the pipe is in the exterior environment, the insulation needs the

addition of 12 mm.

2. The insulation thickness is valid for the materials with thermal

resistance of 28 to 32 m2.K/W per meter. If the thermal resistance is

outside this range, please use the formula in 8.5 of SNI 03-6390-2011 to

calculate the required thickness.

Insulation substantially reduces heat gain in chilled pipe, thus making chiller

load unaffected by thermal heat gain in pipes. The second is to prevent

condensation on the chilled water pipes, which can lead to rusting of the

pipes that can incur significant capital cost to replace.

More information on chilled water pipe insulation is available at:• Hulin, Stanley Quentin. 2010. Insulation Saves Energy, Complies.

with Building Codes (http://www.facilitiesnet.com/energyefficiency/article/Insulation-Saves-Energy-Complies-with-Building-Codes--11686)

• Armacell UK Ltd. How to Guide Insulating Pipes & Fittings with Armaflex. (http://www.armacell.com/WWW/armacell/ACwwwAttach.nsf/ansFiles/ArmaflexHowToPipeWorkPocketGuide.pdf/$File/ArmaflexHowToPipeWorkPocketGuide.pdf)

• Best Practice Manual. Fluid Piping Systems & Insulation. (http://www.energymanagertraining.com/bee_draft_codes/best_practices_manual-PIPING.pdf) (see Chapter 6)

N O T E

I M P A C T

17 Source: SNI 03-6390-2011 (Table 8.5.a).

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Refrigerants used for air conditioning should not contain Chlorofluorocarbons (CFC). (Article 18.5)


Chlorofluorocarbons (CFCs) are a compound of carbon, hydrogen, chlorine

and fluorine that depletes the stratospheric ozone layer. Because of their

stable nature, they do not break up easily, and are able to rise up into the

stratosphere, where they can reduce the ozone. Depletion of the ozone

layer can lead to higher levels of ultraviolet radiation on earth, which can

cause skin cancer, cataracts, impaired immune systems, reduced crop

yields etc. Most countries in the world have banned the use of CFCs,

including Indonesia since 2008. However, chillers with banned refrigerants

are still available in many countries.

As a replacement for CFCs, Hydrochlorofluorocarbons (HCFCs) is now

often used as a refrigerant. However, HCFCs also deplete stratospheric

ozone although to a lesser extent than CFCs. They are also considered as

green house gases, which contribute to climate change due to their high

global warming potential (GWP). Recognizing this, Indonesian government

has put together an HCFC phase out plan, according to which HCFC

consumption in air-conditioning and refrigeration sectors will be completely

phased out by 201518.

It is recommended that chillers with non-HCFC refrigerants be used wherever

feasible. The following graphic shows some safe alternatives to HCFC.

I M P A C T

18 United Nations Environment Programme. Project Proposal: Indonesia. (http://www.multilateralfund.org/62/English%20Document/1/6235.pdf)

19 United Nations Environment Programme. Project Proposal: Indonesia. (http://www.multilateralfund.org/62/English%20Document/1/6235.pdf)

Safe Refrigerant Alternatives to CFCs and HCFC19

F I G U R E . 0 9

R-12 R-12R-717

R-717

R-744

R-744

R-404A

R-600a R-507A R-507AR-22 R-22

R-22 R-502R-1270

R-1270

R-290

R-290R-134a R-290 R-407C R-407C

R-744 R-404A R-404A

NewHFCs/HFOs

Solid Arrows represent alternatives already vailable in the market.Dashed Arrows indicate those likely to be available in the future.

Stand Alone Equipment Condensing Units Centralized Systems

16

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Mechanical system should be designed to provide the minimum ventilation rates per Section 4.4 of SNI 03-6572 2001 (Article 7.3)


For spaces served by a central air conditioner system, mechanical

ventilation system shall be designed to provide the minimum fresh air

supply rate per Section 4.4 of SNI 03-6572 2001 (tables below). Table 4

provides an average ventilation rate based on the building type, whereas

Table 5 provides ventilation rates for specific building functions in the

building. Either of these tables can be used for code compliance. In case

an air duct is supplying air to multiple spaces with different functions, the

highest required ventilation rate among those spaces should be used.

T A B L E . 0 4

T Y P EM I N I M U M F R E S H A I R S U P P L Y

Air Exchange/Hour M3/Hour/Person

Office

Restaurant

Shop, Supermarket

Factory, Workshop

Class, Cinema

Lobby, Corridor, Stairs

Bathroom, Toilet

Kitchen

Parking Area

6

6

6

6

8

4

10

20

6

18

18

18

18

Fresh Air Requirements for Building Types20

20 SNI 03-6572 2001 (Table 4.4).21 SNI 03-6572 2001 (Table 4.4.2).

Closed GarageWorkshop

(m3/min)/person(m3/min)/person

0.210.21

C A R S E R V I C E

T A B L E . 0 5

Laundry (m3/min)/person 0.46

Dining RoomKitchenFast Food

(m3/min)/person(m3/min)/person(m3/min)/person

0.210.300.21

Fresh Air Requirements for Space Types21

B U I L D I N GF U N C T I O N

L A U N D R Y

R E S T A U R A N T

U N I T O U T S I D E A I R R E Q U I R E M E N TNon-Smoking Spaces

Sleeping RoomLiving RoomLobbySmall Meeting RoomMeeting Room

m3/min/personm3/min/personm3/min/personm3/min/personm3/min/person

0.210.750.150.210.21

H O T E L , M O T E L , E T C .

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T A B L E . 0 5

Fresh Air Requirements for Space Types

(continued)



(m3/min)/WC(m3/min)/person

2.250.45


0.150.21

Working RoomMeeting Room

Public ToiletLocker Room

Basement & Ground FloorUpper FloorMall & ArcadeElevator

(m3/min)/person(m3/min)/person(m3/min)/person(m3/min)/person

0.150.150.150.45


0.210.600.210.21


(m3/min)/person(m3/min)/person(m3/min)/person(m3/min)/person(m3/min)/person(m3/min)/person

0.150.210.30

0.150.150.210.210.600.15

m3/min/person 0.21


0.600.420.150.30

Parlor & BarberSport RoomFlorist ShopPet Shop

Disco & BowlingMoving Floor & GymPlaying RoomSwimming Pool

CounterLobby & LoungeStage & Studio

Food ProcessingTreasury BankPharmacyPhotography StudioDark RoomPhoto Printing Room

Waiting Room, Platform,etc.

O F F I C E

P U B L I C R O O M

S H O P P I N G A R E A

B E A U T Y R O O M

E N T E R T A I N M E N T R O O M

T H E A T E R

W O R K I N G R O O M

T R A N S P O R T A T I O N

Patient RoomExamine RoomOperating &Delivery RoomEmergency RoomAutopsy Room

m3/min/bed(m3/min)/person(m3/min)/person


0.210.211.20

0.453.00

H O S P I T A L


0.150.300.15

Class RoomLaboratoriumLibrary

S C H O O L

Living RoomSleeping RoomKitchenToiletGarageJoint Garage

(m3/min)/room(m3/min)/room(m3/min)/room(m3/min)/room(m3/min)/car(m3/min)/m2

0.300.303.001.503.000.45

H O U S E

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High ActivityMedium ActivityLow Activity


0.600.300.21

I N D U S T R Y

Primary benefits of this code requirement are improved occupant health and

comfort. Appropriate ventilation rates result in improved indoor air quality

which can often increase the health and productivity of people in that space.

A study of performance in call centers and simulated office work with

increased ventilation rates shows significant improvement22. Metric

used for performance was the time required to interact with clients via

telephone and perform related information processing on a computer. The

data shows that performance (speed and accuracy) of typical office tasks

improves with increased ventilation rate (see Figure 10 below). For initial

ventilation rates between 0.4 m3/min/person (14 cfm per person) and 0.85

m3/min/person (30 cfm per person), the average performance increases

by approximately 0.8% per 0.28 m3/min/person (10 cfm per person)

increase in ventilation rate. At higher ventilation rates, the average

performance increase is smaller, approximately 0.3% per 0.28 m3/min/

person (10 cfm per person) increase in ventilation rate.

I M P A C T

Average Office Worker Performance at Various

Ventilation Rates23

F I G U R E . 1 0

Minimum Ventilation Rateoften in building codes for offices

Rel

ativ

e P

erfo

rman

ce

Ventilation Rate (cfm per person)10 5030 7020 6040 80

Reference =15 cfm/person



22 Seppänen, O., W.J. Fisk, and Q.H. Lei, “Ventilation and performance in office work”. Indoor Air, 2006. 16(1): p. 28-36.

23 Seppänen, O., W.J. Fisk, and Q.H. Lei. Ventilation and performance in office work Indoor Air, 2006.

1.04

1.03

1.02

1.01

1.00

0.99

0.98

T A B L E . 0 5

Fresh Air Requirements for Space Types

(continued)

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24 Lawrence Berkeley National Laboratory. Indoor Air Quality, Scientific Findings Resource bank. (http://www.iaqscience.lbl.gov/sfrb.html)

25 World Building Design Guide; A Program of the National Institute of Building Sciences. Human Productivity Improvements Linked to Daylighting. (http://www.wbdg.org/design/productive.php)

Similarly in schools, studies have shown a potential for 5% to 10%

increase in student performance with improved ventilation rates24.

A Norwegian study performed in 35 classrooms located in eight schools

used reaction times in a standard test to measure student concentration

and vigilance. Reactions were 5.4% faster with a ventilation rate of 8.1

air changes per hour (ach) corresponding to 26 cfm per person compared

to 2.6 ach (8 cfm per person).

A U.S. study in 5th grade classrooms from 54 schools, used student

performance in standard academic tests as the measure of performance.

Performance in both math and reading tests increased with ventilation

rate. Test scores increased about 13% from classrooms with the

lowest ventilation rates (less than 4.5 cfm per student) to classrooms

with the highest ventilation rates (greater than 9 cfm per occupant). A

Danish study (Wargocki and Wyon) reported a statistically significant 8%

increase in speed of school work tasks with a doubling of ventilation rate.

Since employee salary forms a huge portion of the total operational

cost in a typical office building, even a slight increase in productivity

can offset the additional cost of improving the indoor air quality. A small

increase in productivity savings (1%-5%) can nearly offset a building’s

entire annual energy cost.

As mentioned before, care should be taken that the buildings are not

over-ventilated as that will result in energy wastage. Besides the SNI

03-6572 standard, ASHRAE Standard 90.1 and ASHRAE Standard 62 also

provide some guidance on ventilation design.

Salaries 84%

Energy 1%Maintenance 1%Rent 14%

Break of Operational Cost for a Typical US

Commercial Building25

F I G U R E . 1 1

Commercial Buildings Cost/ S.F.

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More guidance on ventilation systems is available at:• Energy Design Resource. Design Brief, Indoor Air Quality. (http://

www.energydesignresources.com/media/1750/edr_designbriefs_indoorairquality.pdf)

Auditorium, large conference rooms, and similar spaces with occupancy lower than 3 m2/person should be equipped with carbon dioxide (CO2) monitors to limit CO2 concentration to less than 1000 ppm as per ASHRAE 62.1-1989.

C O D E R E Q U I R E M E N T 7A Q 0 1

Ventilation systems are designed to provide fresh air for “design”

occupancies, which are usually much higher than actual occupancy rate

most of the time. This may result in over-ventilation of spaces during

periods of low-occupancy, leading to wastage of energy for fans, cooling

and dehumidification. Demand control ventilation varies the outside

air intake based on actual occupancy in the space without causing any

occupant discomfort. This adjustment in the outside air dampers is

usually done through CO2 or occupancy sensors placed in the room or the

return duct. Since humans exhale CO2, it can act as a measure of human

occupancy in spaces. A commonly accepted maximum limit for CO2

concentration in indoor conditioned spaces is 1000 parts per million (ppm).

A typical application of this control system is in movie theaters, meeting

rooms, auditoriums or ballrooms. If design ventilation rates are not known,

following space types should be provided with CO2 control of ventilation.

I M P A C T

T A B L E . 0 6

O C C U P A N C Y C A T E G O R Y

O C C U P A N C Y C A T E G O R Y

Default Occupant Density

m2/person

Default Occupant Density

m2/person

Classrooms (age 9 plus)

Music/theater/dance

Bowling alley (seating)

Health club/aerobics room

Mall common areas

Museums (children’s)

Museums/galleries

Booking/waiting

Conference/meeting

Legislative chambers

Telephone/data entry

Lecture classroom

Courtrooms

Restaurant dining rooms

Stages, studios

Bars, cocktail lounges

Cafeteria/fast-food dining

Disco/dance floors

Multi-use assembly

Transportation waiting

Multipurpose assembly

Places of religious worship

Auditorium seating area

Lecture hall (fixed seats)

Lobbies

Spectator areas

2.9

2.9

2.5

2.5

2.5

2.5

2.5

2.0

2.0

2.0

1.7

1.5

1.4

1.4

1.4

1.0

1.0

1.0

1.0

1.0

0.8

0.8

0.7

0.7

0.7

0.7

Default High Occupancy Spaces26

26 Source: ASHRAE Standard 62.1 (Table 6-1).

21

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More guidance on demand control ventilation is available at:• Stipe, Marty P. E. 2003. Demand-Controlled Ventilation: A Design

Guide. (http://www.oregon.gov/energy/CONS/BUS/DCV/docs/DCVGuide.pdf)

All closed parking spaces with potential for accumulation of concentrated CO should be equipped with carbon monoxide (CO) monitors to control ventilation. (Article 18.3)

C O D E R E Q U I R E M E N T 7A Q 0 2

Enclosed parking garages face a significant challenge in maintaining good

air quality, because vehicular emissions can raise the concentration of CO

and other noxious gases to dangerous levels. Sustained exposure to even

moderate concentration of CO can cause long term health issues.

The recommended maximum CO concentration beyond which the

ventilation system should come on automatically is 50 ppm.

Use of Carbon monoxide (CO) sensors linked with the ventilation system

prevents the build-up of CO. While this has human health benefits, it can

also save energy by reducing the number of hours when the ventilation

fans need to be running. While a minimum ventilation rate is maintained

at all times, extra fresh air is provided only if the CO levels are high.

I M P A C T

27 Source: Honeywell. Parking Garage Guide. (http://www.honeywellanalytics.com/Technical%20Library/Americas/Parking%20Garage%20Guide/Datasheet/HA%20Parking%20Guide.pdf)

T A B L E . 0 7

T O X I C S Y M P T O M P S & T I M E B R E A T H E D

C O 2 L E V E L I N A I R

ppm %

Death within 1-3 minutes.

Headache, dizziness in 1-2 minutes. Death in 10-15 minutes.

Headache, dizziness, nausea within 10 minutes. Death within 30 minutes.

Headache, dizziness, nausea within 20 minutes. Death within 2 hours.

Headache, dizziness, nausea within 45 minutes, convulsions. Coma within 2 hours.

Frontal headache 1-2 hours, widespread 2½ to 3½ hours.

Slight headache, tiredness, dizziness, nausea after 2-3 hours.

12,800

6,400

3,200

1,600

800

400

200

1.28

0.64

0.32

0.16

0.08

0.04

0.02

Carbon Monoxide Toxicity Levels and Related Health

Symptoms27

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28 Source: Honeywell. Parking Garage Guide. (http://www.honeywellanalytics.com/Technical%20Library/Americas/Parking%20Garage%20Guide/Datasheet/HA%20Parking%20Guide.pdf)

Typical Carbon Monoxide Monitoring System for a

3-Level Parking Structure28

F I G U R E . 1 2

Zone X

Zone Y

Zone Z

LEVEL 1

Daisy Chain up to 32 transmitters



Relay #1 to strobe/horn alarm located on level 1.

Relay #2 to exhaust fan at low speed.

Relay #3 to exhaust fan at high speed.

Relay #4 to malfunction warning light.

LEVEL 2

LEVEL 3

23

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03 other good practices

Primary purpose of air conditioning equipment is to remove indoor heat and moisture. While some of this heat and moisture is generated

within the building by its occupants and equipment, a significantly large

portion of this comes from outdoors through the windows, walls, doors

and air leaks.

Passive design of the building envelope, with due consideration for building

orientation, window shading, glass selection, air tightness, daylighting and

natural ventilation can significantly reduce the cooling load for the building.

For typical Jakarta buildings, this saving potential ranges between 15-30%

of the total energy consumption.

These passive design features can significantly decrease the cooling

requirement, and thus the required cooling system size. It is highly

recommended that cooling load reduction exercise should be done

before cooling system sizing.

R E D U C E C O O L I N G L O A D

Energy Saving Potential of Passive Design

Features in Jakarta29

F I G U R E . 1 3

Air Tightness

Wall Reflectivity

Roof Reflectivity

Glass

Wall Insulation

WWR

Shading

Roof Insulation

Daylight LinkLightling System

HotelRetail HospitalOffice SchoolApartment

Po

ten

tial

En

erg

y S

avin

gs

(%)

0.0

-5.0

10.0 10.1

4.6

10.28.8

5.3

1.9

8.0

3.9

8.7

7.5

2.3

3.5

7.3

3.2

8.5

8.0

6.5

4.2

4.90.3

0.3

0.6

0.3

2.3

2.6

0.2

0.5

0.3

0.5

3.2

-0.9

0.6

0.7

0.5

5.0

15.0

25.0

20.0

30.0

35.0

0.5

0.2

1.0

0.3

0.2

0.5

0.3

0.4

0.6

29 Source: Energy Sensitivity analysis for typical Jakarta buildings by IFC.

Please see the “Building Envelope” user guide for some examples of

passive design features.

1 .

24

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Most buildings will not reach their designed operating efficiencies

immediately after being built. Typically, the tuning process takes 3

to 6 months before reaching the designed operating efficiencies.

Commissioning is the quality control process that verifies and documents that all the building systems comply with the efficiency specifications and meet the needs of building owners and occupants.

Benefits of commissioning are numerous, ranging from lower energy

costs to better occupant comfort and indoor air quality.

Commissioning typically follows these steps:

1. Design Phasea. Selection of a commissioning provider.

b. Designers incorporate commissioning requirements into their

specifications.

2. During Constructiona. Commissioning provider inspects building systems and

components.

b. Near completion, the provider and contractor conduct rigorous

performance tests.

3. Post Constructiona. Commissioning provider delivers training and documentation to

building operators to ensure proper operation and maintenance

of the building.

Often overlooked in Jakarta, proper commissioning of a building

can result in fairly substantial operational savings. USA’s Lawrence

Berkeley National Laboratory analysis (in Table 8 below) of various

commissioned buildings has shown energy savings up to 22% with

less than 1.5 years simple payback.

C O M M I S S I O N I N G

T A B L E . 0 8

Energy Savings and Payback from Commissioning30

30 Lawrence Berkeley National Laboratory; Evan Mills, Ph.D.; Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhouse Gas Emissions; July 21, 2009.

2 .

S O U R C E O F E N E R G Y S A V I N G S

S I M P L E P A Y B A C K T I M E

Higher Education

Food Sales

Hospital Inpatient

Laboratory

Lodging

Retail

Office

11 %

12 %

15 %

14 %

12 %

N/A

22 %

1.5 years

0.3 years

0.6 years

0.5 years

1.5 years

1.4 years

1.1 years

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A thermal zone is a space or group of spaces having similar cooling requirements that may be controlled by a single thermostat.

Each zone’s thermostats can be set to the desired comfort level of

occupants when occupied and cooling can be switched off when

the zone is unoccupied, independent of rest of the building.

Appropriate thermal zoning can save energy as well as enhance

occupant comfort. Improper zoning can result in energy consumption

increase 5-15%31.

Some of the better practices in thermal zoning are:

• 1 zone per floor. Should only be used in open floor plans with

perimeter walls not exceeding 12 meters in length.

• 2 zones per floor (exterior and interior). The exterior zone is directly

affected by outdoor conditions, whereas the interior zone is only slightly

affected by outdoor conditions and usually has uniform cooling.

• 5 zones per floor. For large building footprints, including one zone for

each exposure (north, south, east & west) and an interior zone.

• Zoning based on space use. As shown in table below.

T H E R M A L Z O N I N G

31 Smith, Virginia; Sookoor, Tamim; Whitehouse, Kamin. Modeling Building Thermal Response to HVAC Zoning. (http://www.cs.virginia.edu/~whitehouse/research/buildingEnergy/smith12conet.pdf)

32 Fundamentals of HVAC, ASHRAE Course Reader.

More information on the commissioning process and its benefits can be found at:• Energy Design Resources. Design Guidelines: Commissioning

Guidelines. (http://energydesignresources.com/resources/publications/design-guidelines/design-guidelines-commissioning-guidelines.aspx)

• Mills, Evan; Lawrence Berkeley National Laboratory. Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhouse Gas Emissions. (http://cx.lbl.gov/documents/2009-assessment/lbnl-cx-cost-benefit-pres.pdf)

3 .

T A B L E . 0 9

S P A C E Z O N E C A U S E

Thermal Zoning Based on Space Use32

A theatre used for live

performance

1. Audience

seating

2. Stage

The audience area requires cooling and high ventilation when the

audience is present.

The stage requires low ventilation and low cooling until all the lights

are turned on and then high cooling is required.

26

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Absorption chillers are different from conventional chillers as they use heat instead of mechanical energy to generate cooling. If a source of heat is available on site, such as from an on-site energy

generation plant, absorption chillers could be used to use that energy for

cooling. Although absorption chillers usually have a lower efficiency rating

than the normal centrifugal chillers, they are ideally suited for utilization of

heat that would be otherwise be wasted.

If sufficient solar radiation is available, it could also be used to power

the absorption chillers. Such setup is often called “solar cooling”, and

could result in significant energy savings in tropical climates, such as in

Indonesia. An advantage of solar cooling is that these chillers are more

efficient when the sun is shining at its brightest. Thus the solar heat gain

is largely mitigated by the increased solar cooling efficiency.

A successful large scale example of solar cooling in the region is the

United World College of South East Asia campus in Singapore mentioned

later in this document.

More information on absorption chillers is available at:• Trane, An American-Standard Company. Absorption Water

Chillers, A Trane Air Conditioning Clinic. (http://www.njatc.org/downloads/trc011en.pdf).

A B S O R P T I O N C H I L L E R S4 .

A successful large scale example of solar cooling

in the region is the United World College of South East Asia campus in Singapore mentioned

later in this document.

T A B L E . 0 9

S P A C E Z O N E C A U S E

Thermal Zoning Based on Space Use (continued)

Indoor ice rink

Deep office

Airport

1. Spectators

2. Ice sheet

3. Space above

1. By the

window

2. Interior area

1. Lobby

2. Security

3. Retail outlets

4. Check-in

Spectators need ventilation and warmth.

The ice sheet needs low air speeds and low temperature to minimize

melting.

May need moisture removal to prevent fogging and condensation.

The area may be affected by the heat load from the sun and need more

cooling.

The interior zone load will change due to occupants, lights, and any

equipments.

A huge space with a variety of uses and extremely variable occupancy

and loads.

Each zone requires its own conditions.

27

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One of the highest energy users in a centrifugal or screw type chillers is the compressor. One emerging technology that is making a breakthrough in addressing this high energy use is the oil-free compressor which uses a magnetic drive. Since the drive is

oil free, very less maintenance is needed. This kind of compressor is

more efficient at lower chiller loading as shown in the Table 10 below.

The table shows that the oil-free chiller could be 45% more efficient

than the leading screw type chiller.

M A G N E T I C D R I V E O N C O M P R E S S O R S

5 .

T A B L E . 1 0

Oil Free, Variable Speed, Magnetic Drive Chillers33

ARI 550/590-1198Conditions

Leading ScrewW A T E R C O O L E D

Chiller with Oil FreeW A T E R C O O L E D

LoadECWF/C

LCHWF/C

100 %

75 %

50 %

25 %

85/29.5

75/23.9

65/18.3

65/18.3

44/6.7

44/6.7

44/6.7

44/6.7

kW/Ton kW/TonSCTF/C

SCTF/C

COP COPSSTF/C

SSTF/C

42/5.6

42.3/5.8

42.5/5.9

42.8/6.0

98/36.7

89.6/32

89.6/32*

89.6/32*

5.33

5.73

5.49

4.11

0.64

0.60

0.64

0.845

42/5.6

42.3/5.8

42.5/5.9

42.8/6

98/36.7

85/29.5

72.2/2.2

70.0/21.1

5.56

7.31

11.38

10.86

0.63

0.48

0.30

0.32

kW/TonCOPIPLV 5.4 0.65 9.55 0.36

Because of the uncertainty inherent in design parameters and the liability

risks, most chilled water plants are designed larger than needed.

Oversizing of chilled water plants has multiple impacts as listed below.

• When operating at part loads, an oversized fixed speed chiller may

not perform as efficiently as a smaller machine. Conversely, a variable

speed chiller at part load may operate more efficiently than a smaller

machine at full load.

• Oversized chillers have larger chilled and condenser water pumps

that will consume more energy if the pumps are constant speed. This

penalty can be significantly reduced if the pumps have variable speed

drives or if the chilled water plant consists of multiple smaller chillers.

• The larger piping in the oversized plant will have less pressure

drop (lower pumping energy) than that of a plant whose piping was

“right sized.”

C H I L L E R S I Z I N G6 .

33 Source: Presentation on Oil-free chillers, ASHRAE Puget Sound Chapter. (http://www.pugetsoundashrae.org/EV2030_2008/ev2030oil-freecompressorssm.pdf)

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• An oversized plant’s cooling towers may save energy by allowing

the fans to run slower (with VFDs). Also, they may produce lower

condenser water temperatures for more efficient part-load operation

of the chillers. Conversely, oversized cooling towers may have flow

turndown problems that force the operators to use fewer cells at

higher fan speeds which can increase plant energy use.

• Oversized plants always cost more to build. While a plant’s cost

may not vary linearly with its total capacity, larger plants have more

expensive chillers, larger pumps, and possibly larger piping.

Sometimes providing additional capacity is unavoidable. The owner’s

criteria may call for incorporating redundant chillers or for increasing plant

capacity in anticipation of a future load. Redundant or spare equipment

is a separate issue from oversizing. To mitigate problems with oversized

plants, the chilled water plant must run efficiently at low loads.

The following example from a computer simulation model helps

demonstrate the issue of oversizing. In this case, an 800-ton cooling

plant serves an office complex that operates on a basic five days per

week schedule. Typical load profiles were scaled for peak cooling load of

exactly 450 tons. The plant was modelled with the following scenarios:

• Base Case: A single 800-ton machine with inlet vane control.

• Alt 1: A single 800-ton machine with variable-speed drive control.

• Alt 2: Two 400-ton machines with inlet vane control.

• Alt 3: Two 400-ton machines each with variable-speed drive control.

Cooling Energy Usage for Four Design Alternatives34

F I G U R E . 1 4

Chiller

Tower

ALT 2:2Chillers with IV

ALT 1:1Chillers with VSD

ALT 3:2Chillers with VSD

Base Case0

100,000

300,000

50,000

250,000

150,000

350,000

450,000

200,000

400,000

500,000

Alternative

kWh

/Yea

r

34 Source: CoolToolsTM Chilled Water Plant Design and Specification Guide , , Pacific Gas and Electricity Company. (http://www.stanford.edu/group/narratives/classes/08-09/CEE215/ReferenceLibrary/Chillers/Chilled%20Water%20Plant%20Design%20and%20Specification%20Guide.pdf)

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35 Chilled Water Plant Design Guide by Energy Design Resources. (http://energydesignresources.com/resources/publications/design-guidelines/design-guidelines-cooltools-chilled-water-plant.aspx)

36 Piper, James. 2009. HVAC Maintenance and Energy Saving. (http://www.facilitiesnet.com/hvac/article/HVAC-Maintenance-and-Energy-Savings--10680)

Note the dramatic reduction in annual cooling energy consumption when

the variable-speed drive is added to the 800-ton machine, and also when

multiple machines are added. Although other scenarios may produce

similar or better results, this example illustrates that the energy penalty

for an oversized plant can be dramatically reduced if efficient turndown

is incorporated into the design. By either adding a variable speed drive

on a single chiller or providing two smaller fixed speed chillers the

annual energy is reduced by approximately one third. Combining these

measures (two chillers with variable speed drives) reduces the annual

energy by nearly 50%.

During the design process “right sizing” the chillers is one of the most

cost effective ways of saving energy. Instead of resorting to simplified

rules of thumb, right sizing involves with modeling and/or simulations.

The model or simulations accounts all of passive design features,

building use and operational assumptions to create a typical building

heat load graphs during the day. From this heat load graphs, chiller size

is chosen to allow best chillers combination that resulted in high chiller

loading during the day, which translates to better chiller efficiency as

chillers normally operate more efficiently at higher loading. The model

and simulations may also result in lower capital cost as lower chiller

capacity can be used after taking account of passive design.35

Planned and predictive maintenance of air conditioning system is crucial in getting sustained energy savings. In comparison, reactive

maintenance could be very expensive. Facilities in which proper HVAC

maintenance is completed can use 15% to 20% less energy over the

building’s life as compared to less maintained systems.36

A detailed case study of a university building in North Carolina USA, the

effect of poor maintenance was clearly shown.

M A I N T E N A N C E7 .

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T A B L E . 1 1

S O U R C E O F E N E R G Y S A V I N G S

S I M P L E P A Y B A C K T I M E

Light Sensor

Filters

Fans

Pumps

Cooling Tower

Chiller

Boiler

Thermostats

Humidity

Night Setback

Outside Air

Economizer

Schedule

OK

Clean

Variable Speed

Variable Speed

OK

OK

OK

OK

50%

OK

OK

OK

OK

$ 164,000

30% Overage

Very Dirty

Full Speed

Full Speed

Fouled

Fouled, Poor Charge

Efficiency Loss

3F Drift

40%

Disabled

50% Overage, No Demand

Disabled

1 Hour off

$ 297,852

81.4% increase

Operational Cost Comparison of Good and

Poor Maintenance37

Energy

As shown in the table above, poor maintenance caused an increase of

81% in the annual energy consumption of this building as compared to

the best case scenario.

Some items that caused an increase in energy use of more than 5% in

this building were:

• No fan speed control (VAV installed but running constant speed)

• No pump speed control (VSD installed but running constant speed)

• Chiller fouled or mischarged

• Humidity control failure

• Night setback control failure

• Outside Air Ventilation rate overage

Other maintenance items that impact energy use:

• Replacing compromised temperature sensor/thermostat

• Filter maintenance

• Replacing of fixing automated controls, such as solenoid valves or

motorized valves

ANSI/ASHRAE/ACCA180-2008:Standard Practice for Inspection and Maintenance of Commercial

Building HVAC Systems provides a comprehensive list of inspection and

maintenance tasks that relate to energy efficiency and indoor air quality.

Some of the important preventative maintenance tasks are shown in the

Table 12 below.

37 “The Cost of Doing Nothing” NC Sustainable Energy Conference: April 26, 2011. (https://www4.eere.energy.gov/challenge/sites/default/files/uploaded-files/the-cost-of-doing-nothing.pdf)

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Another good practice is to frequently record and monitor the building’s

energy consumption, which would allow identification of maintenance

problems and remedial measures.

38 Source: ANSI/ASHRAE/ACCA.39 M.R. Brambley et al., “Advanced Sensors and Controls for Building Applications:

Market Assessment and Potential R&D Pathways,” prepared for the U.S. Department of Energy by Pacific Northwest National Laboratory (April 2005), p. 2.7.

T A B L E . 1 2

Key Preventative Maintenance Tasks38

F R E Q U E N C YP R E V E N T A T I V E M A I N T E N A N C E D E S C R I P T I O N

B E N E F I T S

Verify occupied vs. Unoccupied schedules

Check accuracy of thermostats

Check outside air dampers to ensure they

close and open

Calobrate CO2 sensors

Check accuracy of relative humidity sensors

Maintain economizer operation—Check return

air temperature and economizer controllers

Monthly

Annual

Semi-annually

Semi-annually

Quarterly

Semi-annually

Optimize energy use

Reduce equipment run time

Increase comfort

Reduce hot and cold calls

Optimize energy use with controlled setpoints

Ensure adequate ventilation

Reduce wasted energy from excess

ventillation

Ensure adequate ventilation

Reduce wasted energy from excess

ventillation

Increase comfort

Reduce wasted energy in dehumidification

Reduce use of mechanical cooling equipment

Sometimes also known as Building Management System (BMS) or

Environmental Management System (EMS), this is a system of software

and hardware that controls and monitors the building’s mechanical and

electrical equipment such as air handling and cooling plant systems,

lighting, power systems, fire systems, and security systems.

A US study indicates that implementing BAS can result in an average of

10% energy savings for typical US buildings. However, energy savings

can vary depending on the age and maintenance of the building as well as

the implementation of BAS.39

B U I L D I N G A U T O M A T I O N S Y S T E M ( B A S )

8 .

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Sizing pipes and ducts requires careful analysis. Generally, the smaller

the pipework, the greater the pump power and energy consumption.

Increasing the pipe diameter can have a large effect in decreasing

pumping power: smaller friction pressure drops of the basic circuit will

require smaller pressure drops through control valves, for the same

value of valve authority.

The optimum sizing from the point of view of life-cycle costing must

consider the following:

• Length of the system

• The capital cost

• The mean pressure drop

• The running time at full and partial flow

• The efficiency of the pump–motor combination

A general tip on reducing pressure drop across pipe is to replace the

number of 90o bends, especially near the pump output, with 120o or

larger angle bends. This may require the architect and ME consultant to

work together to ensure sufficient space for the piping.

Just as in piping, smaller diameter ducts can increase energy

consumption due to the greater static pressure.

Energy can be reduced in ventilation systems by:

• Avoiding unnecessary bends;

• Using bends instead of elbows;

• Having a ‘shoe’ on the branch fittings for tees;

• Avoiding reduced duct size (i.e. maintain cross sectional area);

• Minimising duct length;

• Minimising the length of flexible ducting;

• Good inlet and outlet conditions either side of fan;

• Using equipment with low pressure drops (i.e. filters, attenuators,

heat exchangers).

• Using the minimum number of fittings possible;

• Ensuring ductwork is sealed to minimize air leakage;

• Using round ductwork where space and initial costs allow because

it offers the lowest duct friction loss for a given perimeter, or given

velocity;

• When using rectangular ductwork, maintain the aspect ratio as close

as possible to 1:1 to minimize duct friction losses and initial cost.

The benefits of the energy efficient (i.e. low velocity) system can show

a reduction in fan electricity costs of up to 70%, while the additional

capital cost can be recovered in less than five years.40

P I P I N G & D U C T I N G9 .

40 Duct & Piping Guideline, May 2011, Kirsten Mariager.

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Some examples of optimal piping layout vs. suboptimal piping layout in

terms of energy efficiency are shown below.Suboptimal Piping layout with Many Bends

Suboptimal Bends Directly at Pump Output

Optimal Piping Layout with Bends at Less than 90o

F I G U R E . 1 5

F I G U R E . 1 6

F I G U R E . 1 7

Source: UWC South East Asia - East Campus

Sharp bend at inlet to

pump causes turbulence

and loss of pump capacity

and efficiency.

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Chiller efficiency is inversely proportional to the temperature of water

entering the condenser from the cooling tower. As demonstrated by the

table below, chiller efficiency can be increased by reducing the entering

water temperature.

It is recommended to follow cooling tower manufacturer’s guideline on

cooling tower placement design. Usually the guideline specifies minimal

distance from cooling towers in order to allow most of the hot air properly

exhausted and not getting into the cooling tower again.

C O O L I N G T O W E R D E S I G N & O P E R A T I O N

1 0 .

T A B L E . 1 3

TYPICAL CHILLER ENERGY-CONSTANT SPEED COP

TYPICAL CHILLER ENERGY-VARIABLE SPEED COP

CONDENSER WATER TEMP (oC)

ENERGY SAVINGS

ENERGY SAVINGS

29.4

28.3

26.7

23.9

21.1

18.3

6.1

6.4

6.6

7.2

7.8

8.4

6.1

6.4

6.6

7.6

8.7

9.8

Base

4.2 %

8.0 %

15.6 %

21.9 %

27.1 %

Base

4.2 %

10.4 %

20.1 %

29.5 %

37.5 %

Typical Impact of Condenser Entering

Water Temperature on Energy Consumption41

Source: Baltimore Air Coil Company

41 Frank Morrison, Baltimore Air Coil Company. (http://www.emersonswan.com/ckfinder/userfiles/files/OPTIMIZING%20CHILLER%20TOWER%20SYSTEMS.pdf)

Suboptimal Cooling Tower Placement

Optimal Cooling Tower Placement

F I G U R E . 1 8

F I G U R E . 1 9

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42 E. Prianto, F. Bonneaud, P. Depecker and J-P. Peneau International Journal on Architectural Science, Volume 1, Number 2, p.80-95, 2000.

Other best practices for cooling tower operations are available at:• Institute of Environmental Epidemiology, Ministry of the

Environment. Code of Practice for the Control of Legionella Bacteria in Cooling Towers (http://www.nea.gov.sg/cms/qed/cop_legionella.pdf & http://www.sydneywater.com.au/publications/factsheets/SavingWaterBestPracticeGuidelinesCoolingTowers.pdf)

One of the ways to reduce mechanical cooling, the highest energy use in most Jakarta buildings is by using substituting mechanical ventilation with natural ventilation. Before the advent of mechanical

cooling, natural ventilation was commonly used to improve occupant

comfort. Traditional Indonesian buildings were designed to allow cross

ventilation and also had high pitched roofs with openings for the hot air

to escape.

Some contemporary low rise buildings have also adopted this traditional

way of cooling buildings. However adoption of these techniques in high

rise buildings is more challenging.

Besides saving operational energy, natural ventilation also saves capital

cost through potential reduction of chiller capacity, supply air ducts,

return air ducts, and other related equipment.

N A T U R A L V E N T I L A T I O N1 1 .

Optimal Air Movement in Traditional and

Contemporary Indonesian Buildings42

F I G U R E . 2 0

a. Air Movement in Traditional Scaffold Houseb. Optimal Natural Ventilation Appearance in Contemporary Building

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Feasibility of natural ventilation depends on the climate and building type.

If the outdoor temperature and humidity levels are close to the comfort

requirement, they can be brought in to relieve the interiors of the built

up heat. In some buildings and climates, energy savings higher than

10% are possible. Jakarta’s outdoor temperature and humidity levels are

usually above the standard indoor comfort conditions of 25oC and 60%

RH. However using the adaptive comfort model from ASHRAE Standard

55 would allow natural ventilation to be used even for higher outdoor

temperatures. This model predicts that occupant tolerance of higher

indoor temperatures increases (pink and light brown bands in the chart

below) when the outdoor temperature is higher.

In order to increase the acceptance of such higher temperatures,

increased air motion could be introduced. For natural ventilation in hot and

humid climates, higher air speeds are desirable in order to improve the

occupants’ thermal comfort. In addition, it is important that the occupants

should be able to control the airflow inside the buildings according to

their preferences. In relation to air movement acceptability subjects in

a study demanded “more air movement” even in airspeeds above 0.50

m/s. On the other hand, the number of subjects who requested “less

air movement” was few in number. These two observations combined

suggest that the occupants prefer higher air speed values in order to

improve their thermal comfort condition.

Mean Outdoor Air Temperature Ta.out (oC)

Ind

oo

r O

per

ativ

e T

emp

erat

ure

(oC

)

Adaptive Comfort Standard for ASHRAE43

F I G U R E . 2 1

80% accept

90% accept

14

18

22

26

30

16

20

24

28

32

5 15 2510 20 30 35

Source: ANSI/ASHRAE Standard 55-2010

43 Candido, Christhina; Dear, Richard de; Lamberts, Roberto, Bittencourt, Leonardo. 2008. Natural Ventilation and Thermal Comfort: Air Movement Acceptability Inside Naturally Ventilated Buildings in Brazilian Hot Humid Zone. (http://nceub.org.uk/uploads/W2008_59Candido.pdf )

A web based tool developed by Center for

the Built Environment (University of California

Berkeley) allows the user to modify various parameters and see its

impact on user comfort. The tool is available at

http://smap.cbe.berkeley.edu/comforttool

37

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While designing and operating naturally ventilation systems in

predominantly mechanically ventilated buildings, conflict between the

two systems should be avoided. For example, if non-automated operable

windows are provided in centrally air-conditioned spaces, they may be

left open and thus result in leakage of cool air. In buildings with unit air

conditioners, such as an apartment, it is easier to incorporate natural

ventilation, since the users have some control on switching between

natural and mechanical ventilation.

Transition spaces which are not occupied continuously such as lobby

and toilets, are also good candidates for natural ventilation. Most Jakarta

buildings do not have automatic doors in the lobby thus allowing a lot of

cold air to escape to the outside. Naturally ventilating the lobbies will also

reduce this cooling energy wastage.

Indonesian standard SNI 6572-2001 recommends providing ventilation openings equal to 5% of the floor area. This standard also provides some guidelines on designing and orienting these openings.

The No. 1 Moulmein Rise apartment building in Singapore offers an

excellent example of a naturally ventilated residential high rise building.

It allows cross ventilation by having a narrow floor plate with only two

apartments per floor. The design also utilizes a traditional technique

of allowing breeze to come while blocking the rain. These “Monsoon

windows” were designed as horizontal grilled openings on the bottom

ledge of the projecting bay windows.

44 Goldhagen, Sarah Williams. Sarah William Goldhagen on Architecture: Living High. (http://www.newrepublic.com/article/books-and-arts/magazine/103329/highrise-skyscraper-woha-gehry-pritzker-architecture-megalopolis#)

Natural Ventilation at Moulmein Rise Apartment, Singapore44

F I G U R E . 2 2

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More guidance on designing naturally ventilated buildings can be found here:• Walker, Andy. 2010. Natural Ventilation (http://www.wbdg.org/

resources/naturalventilation.php?r=env_preferable_products)• Good Practice Guide 237. Natural Ventilation in Non-Domestic

Buildings - A Guide for Designers, Developers, and Owners (http://www.cagbc.org/AM/PDF/GoodPracticeGuide237.pdf)

• Technical papers presented at Council on Tall Buildings and Urban Habitat (CTBUH) conference (available at https://www.ctbuh.org/TallBuildings/TechnicalPapers/tabid/71/language/en-US/Default.aspx) • Natural Ventilation Performance of a Double-skin Façade with a

Solar Chimney by Ding, W., Hasemi, Y. & Yamada • Natural ventilation of tall buildings – options and limitations by

Etheridge, David and Ford, Brian • Office Tower Configuration and Control for Natural Ventilation

by Herman, Matthew; Snyder, Jeremy & Gallagher, Denzil • Natural Ventilation of Residential High-Rises in Subtropical

Regions by Oswald, Ferdinand

It is fairly common for most of the exhaust air to be thrown outside

the building. This causes wastage of energy, since the exhaust air is

usually colder than the incoming fresh air from outside. An energy

recovery ventilation system recovers this energy from the exhaust air and

transfers it to the fresh air stream using a heat exchanger. By removing

sensible heat (temperature) and latent heat (humidity) from outdoor

air, energy recovery systems can save capital cost due to reduction of

cooling system size. Typical heat exchanger types with their efficiency of

recovering the energy from the exhaust air are:

• Run around coil- 55%- 65%

• Enthalpy Wheel- 85%

• Heat pipe: 45%-65%

• Plate heat exchanger: 80%

E N E R G Y R E C O V E R Y1 2 .

According to a published account, some residents are able to avoid use of

mechanical air conditioning through all but the hottest days of the year.

Other interviewed residents have also mentioned that their air conditioning

consumption has been reduced considerably because of the natural

ventilation system.

Ali, Zainab Faruqui. 2007. On Site Review

Report, No. 1 Moulmein Rise (http://www.

akdn.org/architecture/pdf/3291_sin.pdf)

39

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Types of Heat Exchanger Systems

F I G U R E . 2 3 1. Heat Pipe & Run Around Coils. Sensible only.

2. Enthalpy Wheels. Sensible & Latent.

3. Fixed Plate Exchangers. Sensible & Latent.

1. 3.2.

United State Environmental Protection Agency. School Advanced

Ventilation Engineering Software (SAVES) has free software download

for architects, engineers, school officials, and others to select and

compare heat recovery equipment for school buildings.

Any conditioned area with a significant fresh air quantity is a good

candidate for an energy recovery system. However, energy recovery

is generally not cost effective in split or packaged cooling systems.

A general recommendation is to have heat recovery system for single

zone which requires minimum 2000 cfm (944 l/s) of fresh air.

Total Recovery ERV Systems work by reducing the dry bulb and wet

bulb of HVAC Equipment air intake. In the example in Figure 24, the ERV

system is shown to reduce the wet bulb from 26oC to 20oC and dry bulb

from 33oC to 26oC.

SAVEShttp://www.epa.gov/iaq/

schooldesign/saves.html

ERV System Operations45

F I G U R E . 2 4

45 Presentation by ConsERV. (http://www.multistack.com/DesktopModules/Bring2mind/DMX/Download.aspx?EntryId=85&Command=Core_Download&PortalId=0&TabId=136)

40

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Maintenance is an often-overlooked energy conservation measure.

Some items that potentially increases energy use of more than 5% are46:

• No fan speed control (VAV installed but running constant speed)

• Humidity control failure

• Night setback control failure

• Outside Air Ventilation rate overage

Other maintenance items that impact energy use:

• Replacing compromised temperature sensor/thermostat

• Filter maintenance (clean/replace/monitor for filter bypassing)

• Replacing of fixing automated controls, such as automatic air dampers

• Coil cleaning

M A I N T E N A N C E

C E I L I N G F A N S

1 3 .

1 4 .

46 Deferred Maintenance: “The Cost of Doing Nothing” NC Sustainable Energy Conference: April 26, 2011. (https://www4.eere.energy.gov/challenge/sites/default/files/uploaded-files/the-cost-of-doing-nothing.pdf)

According to simulation based sensitivity analysis for typical Jakarta

buildings, a 50% efficient energy recovery system can save 2% to 8% of

the total energy. Savings are usually highest in hospitals as they have high

fresh air requirements.

In hot and humid climates, energy recovery systems with high latent

effectiveness should be selected. Care should be taken that the selected

model is certified for zero leakage to ensure no mixing between outside

fresh air with stale exhaust air.

In hot and humid climates, removal of moisture from the skin uses up a

lot of energy in the cooling and ventilation system. For acceleration of

moisture removal, it is highly effective to introduce additional air movement

through ceiling or wall fans.

41

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Higher air flow also allows increasing the space temperature

while maintaining the same level of comfort, thus reducing energy

consumption further.

According to a study, occupants remain comfortable even at an

thermostat temperature is increased by 2.6oC if air flow is increased to

0.8 m/s through high volume-low speed (HVLS) circulator fans47. As a

rule of thumb—each degree rise in a thermostat setting (beyond 25.56oF)

results in a 6% to 10% saving on cooling energy48. Thus, an increase

in the thermostat setting of 2.6oC could provide cooling energy savings

from 14% to 19%.

To determine the approximate number of regularly sized ceiling fans required to provide appropriate air flow, the following table can be used.

47 Marc E. Fountain and Mward A. Arens, Ph.D, Air Movement and Thermal Comfort, ASHRAE Journal August 1993.

48 US Department of Energy - National Best Practices Manual for Building High Performance Schools.

49 User Guide for Indian Energy Conservation Building Code.

T A B L E . 1 4

R O O M W I D T H

R O O M L E N G T H

3 m4 m5 m6 m7 m8 m9 m10 m11 m12 m13 m14 m

1200/11200/11400/11200/21200/21200/21400/21400/21500/21200/31400/31400/3

1500/11200/21400/2900/41050/41200/41400/41400/41500/41200/61200/61400/6

1400/11400/11400/11400/21400/21400/21400/21400/21500/21400/31400/31400/3

1050/21200/21400/21050/41050/41200/41400/41400/41500/41200/61200/61400/6

1200/21200/21400/21200/41200/41200/41400/4140041500/41200/61200/61400/6

1400/21400/21400/21400/41400/41400/41400/41400/41500/41400/61400/61400/6

1400/21400/21400/21400/41400/41400/41400/41400/41500/41400/61400/61400/6

1400/21500/21500/21500/41500/41500/41500/41500/41500/41500/61500/61500/6

1200/31200/31400/31200/61200/61200/61400/61400/61500/61200/n1400/91400/9

1400/31400/31400/31400/61400/61400/61400/61400/61500/61400/91400/91400/9

1400/31500/31500/31500/61500/61500/61500/61500/61500/61400/91500/91500/9

4 m 6 m 7 m5 m 8 m 10 m 11 m9 m 14 m 16 m12 m

Optimum Size (mm)/Number of Ceiling Fans for Rooms of Different Sizes49

42

AIR

CO

ND

ITIO

NIN

G &

VE

NT

ILA

TIO

N S

YS

TE

M O

TH

ER

GO

OD

PR

AC

TIC

ES

DINAS PENGAWASANDAN PENERTIBAN BANGUNANPEMERINTAH PROVINSI DKI JAKARTA

Jalan Taman Jati Baru No. 1 Jakarta Barat t. (62-21) 856 342f. (62-21) 856 732

www.dppb.jakarta.go.id

Documents

JAKARTA GREEN BUILDING USER GUIDE VOL. 2 AIR ...greenbuilding.jakarta.go.id/files/userguides/Vol-2-Air...2 AIR CONDITIONING & VENTILATION SYSTEM Air Conditioning, Air Quality, and