Thesis Report - Complete[1]

Chapter 1: Introduction

1.1 Research Introduction

Climate change is the change in global weather patterns such as average

temperature, precipitation, day of sunlight and wind patterns. It involves change in

the variability or average state of the atmosphere over a very long period. The

factors which cause the climate change to occur are the effects of human activity, the

variations in solar radiation, greenhouse effect and the earth’s orbit. The main factor

which contributes to climate change is human activity. The human activity is beyond

reasonable doubt lead to current rapid change in the world’s climate. The biggest

factor of the recently concern is the increasing of CO2 level due to emissions from

fuel combustion in automotive field, aerosols which exert a cooling effect, and

cement manufacture. The rapid development of generation, also cause a lot of forests

are destroyed for new development purpose. Consequently, the unbalance ecosystem

will lead to climate change rapidly. One of the significant effects is greenhouse

effect. Greenhouse effect means the change in the concentration of the gases such as

water, vapor, CO2, CH4, N2O, and CFCs which trap infrared radiation from the

Earth’s surface. The average temperature of the world indirectly also will increase

due to greenhouse effect.

Library is a collection of information, sources, resources and services.

Library is also called collection of books in more traditional sense. In university, the

library becomes the important place for students to search for information and

studying. Therefore, the indoor environment quality (IEQ) plays an important role

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for health and comfort of library. The IEQ includes temperature, relative humidity,

concentration of CO2, concentration of CO, microbial contaminants, moisture, air

velocity, noise from outside, vibrations, visual or lighting quality and etc. In fact,

indoor air is often a greater health hazard than the corresponding outdoor condition.

This is because indoor is a close surface system, the unhealthy conditions will trap in

the close surface system and lead to health problem. From the occupant point of

view, the idea situation of the indoor environment should satisfy all occupants and

does not unnecessarily increase the risk or severity of illness or injury. (Hazim B.

Awbi, 2008)

HVAC system installed is to create or maintain the cooling and comfort in the

libraries. However, due to the climate change recently, the increasing of outdoor

temperature causing more heat to be transfer into the indoor of the building. Hence,

the HVAC system needs to provide more cooling capacity to absorb the heat from

outdoor. The buildings normally have to survive for at least 50 years, the HVAC

system normally will design base on the climate during that time, so, sustainability of

the HVAC system to provide the acceptable cooling and comfort level becomes a

main concern in this thesis.

Two libraries had been chosen in the tropical climate for my research work.

They are Law faculty library and Engineering faculty library in University of

Malaya. Both libraries are chosen for my research work is because they are built at

different period of year. The air conditioner system of Law faculty library was

installed during year 1997 while the air conditioner system of Engineering faculty

library was installed during year 1985. This indicates that the air conditioner systems

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installed in both of the libraries were in different of time based on the climate at that

moment. Therefore, a comparison of the both of the air conditioner systems can be

implemented to monitor the effect of the climate change to the design of the air

conditioner systems in both of the libraries.

To have more accuracy of prediction of trend of temperature and relative

humidity inside both of the libraries in future, the actual current indoor environment

quality was carried out. Few parameters were measured such as temperature, relative

humidity, the concentration of carbon dioxide (CO2), the concentration of carbon

monoxide (CO), air flow rate and particle count.

Besides, the Transient System Simulation Program (TRNSYS) is used to

predict the trend of temperature and relative humidity in both of the libraries based

on the climate change in the tropical climate. Before that, the new weather profile

need to generate based on the latest climate profile. By using TRNSYS program,

analyzing of the both air conditioner systems can be carried out.

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1.2 Research Objective

To investigate the effect on the HVAC system taken into account of climate

change implication for the building and their technical services in tropical

climates.

To analyze the current situation of HVAC systems of Law faculty library and

Engineering faculty library.

To carry out empirical studies of Indoor Environment Quality (IEQ) of Law

faculty library and engineering faculty library.

To compare the trend of temperature and relative humidity of current

situation and future prediction.

To use Transient System Simulation Program (TRNSYS) to simulate the

HVAC systems using the weather profile created base on climate change

running at full load, 75% full load and half load.

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Chapter 2: Background and Literature Review

2.1 Heat Transfer by conduction and radiation

To more understand about the how the climate change influence the

performance of HVAC system and indoor environment quality, the effect of heat

transfer, conduction, radiation, sensible heat and latent heat need to take in

consideration. Of course, when the temperature outdoor is higher compare to indoor,

the heat will transfer from outdoor to indoor. There are two ways of heat transfer can

be occur, conduction and radiation through the wall and window of the buildings.

The heat can transfer from outdoor into indoor through the wall by conduction.

However, the major heat will transfer from outdoor into indoor through the window

by conduction and also radiation. If the unshaded windows are exposed to the solar

radiation, about 8 percent of the radiant energy is typically reflected back outdoors,

from 5 to 50 percent is absorbed within the glass, the percentage of heat absorbed is

depend on the composition and the thickness of the glass. The remainder is

transmitted directly into indoor; it will become part of the cooling load.

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Outward flow of absorbedradiation –8%

Incoming solar radiation--100% Inward Flow of

absorbed radiation –4%

Transmitted solar radiation--80%

Reflect radiation--8%

Total solar heat admitted--84%

Total solar heat excluded--16%

The solar heat gain is the sum of the transmitted radiation and the portion of the

absorbed radiation that flows inward. Moreover, heat also transfer through the glass

by conduction whenever there is an outdoor-indoor temperature difference, so, the

total rate of heat admission is:

Total heat admission through glass = Radiation transmitted through glass + Inward

flow of absorbed solar radiation + Conduction heat gain

(Face C. McQuiston, 2004)

2.2 Sensible Heat and Latent Heat

Besides, the indoor environment quality not only depends on the conduction

and radiation from the outdoor, the sensible heat and latent heat also contribute to the

cooling load. All matter typically exists in one of the three states: it is a solid, a liquid

or a gas. Sensible heat means heat that changes the temperature of a substance

without changing the substance’s state. It can be measured simply using

thermometer. The unit of the sensible heat is Btus per hour (Btu/hr).

Latent heat or hidden heat is the heat required to change the state of a

substance at the temperature. Latent heat needs to add to change the material from

solid phase to liquid phase or from liquid phase to gas phase. On the other hands, the

latent need to remove for changing phase of material from gas phase to liquid phase

or from liquid phase to solid phase. The changing of water between its three phases

requires the addition or removal of latent and sensible heat. The heart of the HVAC

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Figure 2-1: Distribution of solar radiation falling on the clear plate glass

system controls the latent and sensible heat. For example, 144 Btu of latent heat is

taken to convert one pound of ice at 32˚F to one pound of water at 32˚F or vice versa.

This type of heat is called latent heat of fusion. Another example, 180 Btu of sensible

heat is taken to raise the temperature from 32˚F to 212˚F of one pound of the water.

The exchange heat, either sensible heat or latent heat, is the basis for most

heating and air-conditioning processes. In these HVAC processes, heat is added or

removed from a medium such as water or air at a central point and then distribute

this heated or cooled medium to all parts of the structure where it will be used to

warm or cool the space. (Alan J. Zajac, 1997)

2.3 Ventilation system

Moreover, the ventilation system also plays an important role to maintain the

indoor environment in a good condition. According to the Oxford Dictionary,

ventilation is to ‘expose to fresh air’ and to ‘cause air to circulate freely in an

enclosed space’. The main purpose of the ventilation system is to provide the

untainted air for occupants in indoor environment. The volume of air necessary to

provide for human may be considered in following principal headings:

Provision of oxygen for respiration

Removal of products of exhalation

Removal of body odor

Removal of unwanted heat

Removal of unwanted moisture and contaminants.

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At the rest condition, the normal adult inhales between 0.20 and 0.12 liter/s of

air and of this only about some 5% is absorbed as oxygen by the lungs. After that, the

exhaled breath contains about 3% to 4% of CO2 which equal to about 0.004 liter/s.

The concentration of CO2 at an indoor environment with accepted level is 500ppm or

0.5% by volume for an exposure of 8 hours.

A good ventilation system can remove the odors arising from human occupation

which the problem normally becomes serious only in crowded places. The unwanted heat

means the sensible heat. The unwanted heat needs to remove so that the comfort temperature

can be maintained. Ventilation system also used to remove the unwanted moisture in indoor

environment. For example, if the moisture is high in libraries, it will give the impact to the

books in libraries. The contaminants in indoor environment arising from tobacco smoke.

However, the libraries do not face this type of problem because libraries are non smoking

area. (P. L. Martin, 1995)

2.4 Heat Balance Method

The concept of a design cooling load derives from the need to determine an

HVAC system size that, under extreme conditions, with provide some specified

condition within a space. The space served by an HVAC system commanly is

referred to as a thermal zone or just a zone. Usually, the indoor boundary condition

associated with a cooling load calculation is a constant interior dry-buld temperuture,

but it could be a complex function, such as a thermal comfort condition. Generally,

for an office it would be assumed to be a clear sunlit day with high outdoor wet-bulb

and dry-bulb temperature, high office occupancy and a correspondingly high use of

equipmet and light. It is apparent that the boundary conditions for a cooling load

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determination are subjective. But, after the design boundary conditions are agreed

upon, and then the design cooling load represents the maximum or peak heat

extraction rate under those boundary conditions.

A complete, detailed model of all of the heat transfer processes occurring in a

building would be very complex and would be impractical as a computational model

even today. However, there is fairly good agreement among building physics

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Radiation

Convection to outside air

Absorbeb incident

solar Outside face heat balance

Through the wall

conduction

HVAC system

air

InfiltrationVentilationExhaust air

Convection from internal

source

Radiation from internal

sources

Radiation from light

Transmitted solar

Radiation exchange with other surfaces

Air heat balance

Convection to zone air

Inside face heat balance

Figure2-2: The schematic heat balance model.

researchers and practitioners that certain modeling simplifications are reasonable and

appropriate under a broad range of situations. Therefore, the simple model becomes

the basis for most discussions of the heat transfer. The resulting formulation is called

Heat Balance (HB) method. The processes that make up the heat balance model can

be visualized using the schematic shown in figure 2-2. It consists of four distinct

processes. They are:

1. The outside face heat balance,

2. The wall conduction process,

3. The inside face heat balance,

4. The air heat balance.

2.5 Radiant Time Series (RTS) method

The radiant time series (RTS) method is a new method for performing design

cooling load calculations. It is derived directly from the heat balance method, and

effectively replaces all other simplified (non-heat-balance) methods such as the

transfer function method, the cooling load temperature difference/solar cooling

load/cooling load factor method, and the total equivalent temperature difference/time

averaging method. RTS was developed in response to TC 4.1’s desire to offer a

method that was rigorous, yet did not require iterative calculations of the previous

method. In addition, for pedagogical reasons, it is desirable for the user to be able to

inspect and compare the coefficients for different zone types. (Curtis O. Pedersen et

al, 1998).

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(Source: Internet Reference, (13/1/2009a))

Figure 2-3: Fan Coil Unit

2.6 Fan Coil Unit

A fan coil unit (FCU) is a simple device consisting of a heating or cooling

coil and fan. It is part of an HVAC system found in residential, commercial, and

industrial buildings. Since it does not have any duck work, a fan coil unit is used to

control the temperature only in the space where it is installed. It is controlled either

by a manual on/off switch or by thermostat. Due to their simplicity, fan coil units are

more economic to install than ducted or central heating systems. However, they can

be noisy because its fan is within the same space.

The coil receives hot or cold water from a central plant, and removes or adds

heat from the air through heat transfer. Fan coil units can contain their own internal

thermostat, or can be wired to operate with a remote thermostat.

Fan coil units circulate hot or cold water through a coil in order to condition a

space. The unit gets its hot or cold water from a central plant, or mechanical room

containing equipment for removing heat from the central building's closed-loop. The

equipment used can consist of machines used to remove heat such as a chiller or a

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cooling tower and equipment for adding heat to the building's water such as a boiler

or a commercial water heater.

Fan coil units are divided into two types: two pipe fan coil units or four pipes

fan coil units. Two pipe fan coil units have one supply and one return pipe. The

supply pipe supplies either cold or hot water to the unit depending on the time of

year. Four pipe fan coil units have two supply pipes and two return pipes. This

allows either hot or cold water to enter the unit at any given time.

In high-rise residential construction, typically each fan coil unit requires a

rectangular through-penetration in the concrete slab on top of which it sits. Usually,

there are either 3 or 5 copper pipes that go through the floor. The pipes are usually

insulated with refrigeration insulation, such as acrylonitrile butadiene/polyvinyl

chloride (AB/PVC) flexible foam (Rubatex or Armaflex brands) on all pipes or at

least the cool lines. (Internet Reference, 12/1/2009).

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Figure 2-4: Fan coil unit layout

(Source: Internet Reference, (30/3/2009))

2.7 Air Handling Unit

2.7.1 Definition

Air Handling Units are often called AHU. The air-handling unit is box-like

equipment with a fan and a cooling coil inside. Some units also contain air filters.

The whole fan and motor assembly, comprising shaft, bearings, pulley, and belting

are usually put inside the AHU.

The basic function of the AHU is to suck air from the rooms, let it pass

through chilled water cooling coils and then discharging the cooled air back to the

rooms. Normally, letting it pass through panel or bag filters also filters the air. A

certain amount of fresh air may be introduced at the suction duct so that air in the

rooms may be gradually replaced. AHU's come in many sizes and shapes. Usually,

the air conditioning designer will choose a particular AHU based on the air flow

requirements and the cooling capacity. If humidity of the air has to be controlled,

steam coils, or other heating coils may be installed. If the air has to be very cleaned,

special HEPA filters have to be installed at the ducting outlets or at the AHU filter

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Figure 2-5: Air Handling Unit

Source: Internet Reference, (13/1/2009b)

box. Moisture in the air is condensed out when it comes into contact with the chilled

water coils. At the bottom of the AHU, a pipe is installed so that water that is

collected can be drained out.

The fan and motor assembly is usually mounted on vibration dampers that

absorb any vibrations generated. Removable panels are installed so that personnel

can enter into the AHU for maintenance. Maintenance is mostly changing or washing

of air filters, greasing of bearings, changing of belts, and general inspection and

cleaning work.

2.7.2 Temperature Control

Controlling the flow of chilled water through the cooling coils alters the

temperature of the discharged air into the rooms. Control valves are used to throttle

chilled water through the chilled water coils. A simple temperature control system

uses thermostats to control on-off solenoid valves. A better control system uses

temperature sensors, controllers, and motorized control valve. More complicating

systems may have motor speed control for the fan.

2.7.3 Humidity Control

Some critical processes may require that the humidity of the air-conditioned

space be controlled. During the normal cooling process, as the air becomes cooler,

the relative humidity of the air tends to increase. If the relative humidity have to be

brought down, the air have to be heated by steam coils or other means. Steam coils, if

installed will have their own controls. A typical control system has a temperature

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sensor, controller, and control valve. Usually, humans monitor the relative humidity,

and the steam controller settings are adjusted accordingly. (Internet Reference,

2/12/2008).

2.8 Weather Data

The weather data of Kuala Lumpur for 20 years periods were provided by

Malaysian Meteorological Department. The weather data provided was used to

generate TMY2 weather profile file which can used to predict the future trends of the

weather profile. The generation and assessment of building simulation weather files

was did by (Mark F. Jentsch et al.) in United Kingdom. In their research, they stated

that current industry standard weather files for building simulation are not suited to

the assessment of the potential impacts of a changing climate. This research

describes the integration of future UK climate scenarios into the widely used Typical

Meteorological Year (TMY2) and EnergyPlus/ESP-r Weather (EPW) file formats

and demonstrates the importance of climate change analysis through a case study

example. (Mark F. Jentsch et al. 2008).

Besides, from Lisa Guan research study, she also stated that in order to study

the impact of climate change on the building environment, the provision of suitable

weather data become critical. She presented an effective framework and procedure to

generate future hourly weather data. It is shown that this method is not only able to

deal with different levels of available information regarding the climate change, but

also can retain the key characters of a ‘‘typical’’ year weather data for a desired

period. (Lisa Guan, 2008).

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Chapter 3: Methodology

3.1 Literature review

The related books, journal papers, thesis about my thesis topic are searched

and studied to have a clear understanding of my thesis scopes, background

and objectives.

3.2 Fieldwork study planning

Before carry out the effective fieldwork study at Law faculty library and

Engineering faculty library, good strategies need to plan.

The existing HVAC systems and floor areas were studied from mechanical

and electrical (M&E) drawing; related data and suitable instruments were

identified and prepared.

Manual of instruments were read and demonstration of the instruments was

made by the supervisor.

Data tables were created to record the data.

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3.3 Fieldwork study

Firstly, divide the floor plan of the libraries into smaller zone to increase the

accuracy of the measurements.

The indoor environment qualities (IEQ) were measured such as dry bulb

temperature, wet bulb temperature, relative humidity, CO2 concentration, CO

concentration, air velocity and air volume flow rate at each single zones.

The IAQ monitor was used to measure dry bulb temperature, wet bulb

temperature, relative humidity, CO2 concentration and CO concentration.

The air velocity was measured by using air velocity meter.

The probe of IAQ monitor was placed around 1.2 meter from the ground.

Wait few minutes for the reading to be stabilized.

The same procedures were applied to air velocity meter for air velocity

measurement.

Balometer was used to measure the air volume flow rate at each diffuser in

both of the libraries.

The outdoor conditions such as dry bulb temperature, relative humidity also

were measured.

The specifications of HVAC system were recorded for analyzing and

simulating purpose.

Data Logger was installed to record the continuous changing in dry bulb

temperature and relative humidity of both of the libraries for one week.

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3.4 Data analyzing

From the data recorded, the data are key in into proper tables in the computer

for the ease of analyzing work.

Heat load of each library was calculated by using heat load calculation form

provided in Carrier Handbook.

3.5 Simulation

TRNSYS simulation is used to simulate the HVAC systems of both of the

libraries and to predict the sustainability of the HVAC system for 20 years

downward by using the latest weather profile.

3.6 Comparison

After analyze the data, the results obtain need to compare with the standard

value which provided in the ASHERE handbook.

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3.7 Instrumentation Description

3.7.1 IAQ Monitor (KANOMAX-model 2211)

This equipment is used to measure the concentration of CO2 and CO,

relative humidity, absolute humidity and dew point, wet bulb

temperature.

3.7.2 Air Velocity Meter (TSI-model 8345)

This meter is used to measure on the air velocity, temperature and also

flow rate. To measure for air velocity, the sensor needs to hold

perpendicular to the air flow direction.

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Figure 3-1: IAQ Monitor (KANOMAX-model 2211)

Figure 3-2: Air Velocity Meter (TSI-model 8345)

3.7.3 Balometer (Models EBT720/EBT721)

This equipment is used to measure pressure, temperature, relative

humidity, air velocity and air flow rate.

3.7.4 Data Logger

It is used to log the temperature and relative humidity for certain area for a long period.

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Figure 3-3: Balometer (Models EBT720/EBT721)

3.7.5 Transient System Simulation Program (TRNSYS)

The TRNSYS was used to simulate the HVAC systems.

Chapter 4: Field Work Study

4.1 Overview of the Existing Air-Conditioning System in Law

Faculty Library

4.1.1 Introduction

The Law faculty library is currently using water cooled air conditioning

system (WCP). The WCP consists of Air Handling Unit (AHU), pumps and cooling

tower. There are total 4 floors in Law faculty library. Each floor consists of 2 units of

Air Handling Units (AHU) at 2 end of the Floor. All of the AHU are connected to a

cooling tower. There are also 3 pumps to pump and circulate the cooling water

between AHU and cooling tower.

Basically, the system has 3 loops of circles, such as air loop, refrigerant loop

and cooling water loop. Firstly, for the air loop, the air is drawn back from the indoor

of the library to AHU room, then the air is mixed with the fresh air which drawn in

form outdoor. After air mixing, the mixing air will pass through the filter and cooling

coils in the AHU. The cooling and dehumidification process will take place here.

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Figure 3-4: Data Logger

After cooling and dehumidification process, the air will blow into indoor of the

building by a fan.

The second loop is refrigerant loop. The function of refrigerant loop is to

absorb the heat in the air which passes through the cooling coil. There are 4 units of

compressor inside each AHU to compress the evaporate refrigerant.

Thirdly, the air conditioning system needs another loop called cooling water

loop to transfer the heat from the refrigerant to ambient. Cooling water loop needs

pumps to circulate the water from AHU to Cooling tower and heat is transferred to

the ambient at cooling tower.

4.1.1.1 AHU Specifications

Floor

AHU 1 AHU 2

Model Cooling Capacity (Btu/hr)

Model Cooling Capacity (Btu/hr)

Ground Floor Dunham-Bush WCP510

510000 Dunham-Bush WCP510

510000

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Cooling Tower

AHU Space

Refrigerant Loop

Cooling water Loop

Air Loop

Figure 4-1: Water Cooled Package Air Conditioning system diagram.

First Floor Dunham-Bush WCP510


365000

Second Floor Dunham-Bush WCP435


435000

Third Floor Dunham-Bush WCP580


510000

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Table 4-1: The models and cooling capacities of AHUs for each floor.

Figure 4-2: Top view of cooling tower Figure 4-3: Side view of cooling tower

Figure 4-4: Pumps Figure 4-5: AHU

Figure 4-6: Off-grill Figure 4-7: Data measuring

4.1.2 Result and Analyzing

4.1.2.1 Ground Floor Results

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Figure 4-8: Graph of Temperature and relative humidity of ground floor compare to comfort temperature and recommended relative humidity.

Figure 4-9: Graph of CO2 concentration of ground floor compare to maximum limit of CO2 concentration.

Parameter Reading

Maximum Temperature (˚C) 23.8Minimum Temperature (˚C) 21.1Average Temperature (˚C) 22.2Maximum RH (%) 72.7Minimum RH (%) 58.0Average RH (%) 68.0Maximum CO2 (ppm) 597Minimum CO2 (ppm) 374Average CO2 (ppm) 464Maximum air flow (m/s) 0.24Minimum air flow (m/s) 0.04Aver air flow (m/s) 0.15

4.1.2.2 Discussion

From the results obtained, the temperature average temperature at the ground

floor of the Law faculty library is 22.2˚C. Beside the range of the temperature at this

floor is lower than the comfort temperature. The range of temperature is between

21.1˚C and 23.8˚C. The occupants who stay at this floor will feel cool.

Next, the average of the relative humidity at the ground floor is 68% RH. The

maximum relative humidity and minimum relative humidity at this floor are 58% RH

and 72.7% RH respectively. According to ASHRAE Handbook, the recommendation

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Table 4-2: Results summary for ground floor.

range of relative humidity in the library is between 50% RH to 60%RH. Therefore,

the relative humidity of this floor already exits the maximum range of relative

humidity.

The average concentration of CO2 at the ground floor of the Law faculty

library is 464 parts per million (ppm). The range of the CO2 concentration at the

ground floor is between 374 ppm and 597ppm.

From WHO ISO 7730, the limit of the air movement is 0.25m/s. From the

measurement conducted, the maximum air flow and minimum air flow are 0.24m/s

and 0.04m/s respectively. The average of the air flow is 0.15m/s. The air flows at this

floor are considered acceptable.

4.1.2.3 First Floor Results

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Figure 4-10: Graph of Temperature and relative humidity of first floor compare to comfort temperature and recommended relative humidity.

Figure 4-11: Graph of CO2 concentration of first floor compare to maximum limit of CO2 concentration.

Parameter Reading


4.1.2.4 Discussion

From the results measured, the average temperature, 22.2˚C, which is lower

than comfort temperature, 24˚C. Besides, the maximum temperature and the

minimum temperature are 24.1˚C and 20.9 respectively. Therefore, the condition in

the first floor of the Law faculty library is considered cool.

The relative humidity range at this floor is between 56.3% RH to 62.9% RH.

The average of relative humidity is 60.4% RH. The relative humidity at this floor is

considered acceptable.

The concentration of CO2 is at acceptable level because the average of CO2

concentration is 423 ppm and lower than maximum limit of CO2 concentration level.

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Table 4-3: Results summary for first floor.

The range of CO2 concentration at this floor also below the maximum limit of CO2

concentration level which between 387 ppm and 477 ppm.

The range of the air flow is between 0.01m/s to 0.15m/s and its fall into an

acceptable range.

4.1.2.5 Second Floor Results

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Figure 4-12: Graph of Temperature and relative humidity of second floor compare to comfort temperature and recommended relative humidity.

Figure 4-13: Graph of CO2 concentration of second floor compare to maximum limit of CO2 concentration.

Parameter Reading

Maximum Temperature (˚C) 26.2Minimum Temperature (˚C) 20.4Average Temperature (˚C) 22.1Maximum RH (%) 65.3Minimum RH (%) 55.1Average RH (%) 61.3Maximum CO2 (ppm) 495Minimum CO2 (ppm) 360Average CO2 (ppm) 398Maximum air flow (m/s) 0.17Minimum air flow (m/s) 0.01Average air flow (m/s) 0.08

4.1.2.6 Discussion

At Second floor of the Law faculty library, the average temperature is 22.1˚C

which is lower than the comfort temperature. From the graph 4-12, it shows from

zone 52 to zone 59 have the temperature which higher than comfort temperature.

This is because the zone 52 to zone 59 are near the window and the wall of the

building, more heat is transfer into these areas and cause the temperature of these

zones are higher than comfort temperature. However, these zones still lower the

maximum limit of the temperature which will cause heat stress inside the building..

The maximum limit of the temperature is 28˚C.

The range of the relative humidity in this floor is between 55.1% RH to

65.3% RH. From the calculation, 63% of zones are higher than the maximum

acceptable range of the relative humidity.

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Table 4-3: Results summary for second floor.

For concentration of the CO2, the maximum CO2 concentration and minimum

CO2 concentration are 495 ppm and 360 ppm. All the CO2 concentrations at every

zones are lower than maximum limit of CO2 level inside a building.

The average air flow at this floor is 0.08 m/s. the range of the air flow is

between 0.01 m/s to 0.17 m/s. Therefore, it is fall into satisfaction range according to

the WHO ISO 7730.

4.1.2.7 Third Floor Results

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Figure 4-14: Graph of Temperature and relative humidity of third floor compare to comfort temperature and recommended relative humidity.

Figure 4-15: Graph of CO2 concentration of third floor compare to maximum limit of CO2 concentration.

Parameter Reading


4.1.2.8 Discussion

The graph 4-14 shows that the maximum temperature and minimum

temperature at 3rd floor of the Law faculty library are 21.5˚C and 26.2˚C respectively.

It also shows that almost 85% of the zones temperatures are higher than the comfort

temperature. The average of temperature is 24.8˚C. 85% of the zones temperatures

are higher than comfort temperature because one of the AHU was under technical

maintenance at the moment which the measurement was conducted. Besides, 3 rd floor

is the highest floor in the building; the additional heat is transfer into the areas

through the roof compare to other floors. Hence, 3rd floor of the Law faculty library

will experience higher heat transfer form outdoor environment to indoor

environment.

The average relative humidity of this floor is 71.2% RH. The range of the

relative humidity is between 60.8% RH and 75.8% RH. The relative humidity of this

floor is all out of the maximum recommendation relative humidity. The most

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Table 4-4: Results summary for third floor.

significant impact of relative humidity to the indoor environment is fungal growth.

There are a lot of valuable books and collections inside the library, the growth of the

fungal will damage the valuable book and collection because fungal are growth faster

at high relative humidity condition.

The level of CO2 at this floor is acceptable due to the range of CO2

concentration obtained is between 304 ppm and 471 ppm. The average of the

concentration of CO2 is 340 ppm.

The air flow also satisfies the standard condition with the range of air flow

obtained was between 0.01 m/s and 0.22 m/s. The average of air flow of this floor is

0.08 m/s.

4.1.3 Volume Flow Rate Analyzing

Volume flow rate of air is the total volume of air blow into the indoor

environment by the air handling unit (AHU) of air conditional system per unit time.

In the Law faculty library, there are total 8 units of AHU provide the air flow into the

indoor environment to certain areas by ducting system.

4.1.3.1 Methodology

Diffuser volume flow rate measurement

First, all the location of diffusers at each area in the Law faculty library were

recognized and recorded into the floor plan.

Then, volume flow rate of diffuser were measured by using balometer and the

data obtained were save into the meter logger.

32

Next, all the saving data were extracted to the computer.

Finally, data obtained were organized into a proper form and analyzing is

made through the results.

Inlet air flow measurement

All the AHUs in the Law faculty library were identified and the cooling

capacities of each AHU were recorded.

Then, the air velocity of the inlet were measured and saved in the meter

logger.

Next, the areas of the air inlet of AHUs were measured with the measuring

tapes.

Finally, data were extracted into the computer and analyzing was made

according to the results obtained.

4.1.3.2 Results

GF 1F 2F 3FTotal Air Flow Rate Measured (CFM) 17841 16436 12728 17479AHU cooling capacity (RT) 85 72.9 72.5 90.8Rated Volume Flow Rate (CFM) 34000 29160 29000 36320Maximum Temp of Air Flow ( °C) 22.1 20.9 22.3 24.2Minimum Temp of Air Flow ( °C) 16.4 19.9 20.1 20.3Average Temp of Air Flow ( °C) 18.7 20.5 21.4 21.3

Floor Air Inlet Air Inlet Air Inlet Air Volume Flow

33

Table 4-5: Volume flow rate of diffusers.

Width (ft) Depth (ft)

Area (ft2)

Velocity(ft/Min) Rate (CFM)

GF-a 2.30 7 32.20 432.44 13924.49

GF-b 2.30 7 32.20 425.25 13693.05

1F-a 2.30 7 32.20 420.56 13542.11

1F-b 3.16 7 22.12 404.38 8944.78

2F-a 3.16 7 22.12 475.50 10518.06

2F-b 3.16 7 22.12 498.13 11018.53

3F-a 2.30 7 32.20 448.56 14443.71

3F-b 2.30 7 32.20 366.75 11809.35

FloorCooling Capacity

(RT)

Rated Volume

Flow Rate (CFM)

Inlet Volume Flow Rate

(CFM)

Off grill Volume Flow

Rate (CFM)

Percentage of loss

(In-out)/In (%)

GF 85 34000 27617.54 17841 35.40

1F 72.9 29160 22486.89 16436 26.91

2F 72.5 29000 21536.59 12728 40.90

3F 90.8 36320 26253.06 17479 33.42

34

Table 4-6: Inlet air flow reading.

Table 4-7: Percentage loss of volume flow rate.

4.1.3.3 Discussion

From the table 4-7, it had shown percentage of losses of the volume flow rate.

The percentage of the losses of ground floor, first floor, second floor and third floor

were 35.40%, 26.91%, 40.90% and 33.42% respectively. From the measurement, the

second floor had the highest losses of the volume flow rate compare to other floors.

There are few factors causes the losses of the volume flow rate. Firstly, the losses of

volume flow rate are due to the friction inside the ducting system. The higher the

friction inside the ducting system, the higher the losses of volume flow rate.

Secondly, the losses of volume flow rate are due to the leakage of the system. The

leakage of the system causes the air flow can not deliver to the off-grill in the

building. Finally, the pressure inside the building also will give impact to the losses

of volume flow rate.

4.1.4 Data Logger

4.1.4.1 Results

35

Figure 4-16: Graph of Temperature and relative humidity of ground floor. (1)

Figure 4-17: Graph of Temperature and relative humidity of ground floor. (2)

Figure 4-18: Graph of Temperature and relative humidity of first floor. (1)

36

Figure 4-19: Graph of Temperature and relative humidity of first floor. (2)

Figure 4-20: Graph of Temperature and relative humidity of second floor. (1)

Figure 4-21: Graph of Temperature and relative humidity of second floor. (2)

Figure 4-22: Graph of Temperature and relative humidity of third floor. (1)

Figure 4-23: Graph of Temperature and relative humidity of third floor. (2)

4.1.4.2 Results summary of Data Logger

FloorMax

Temp (˚C)

Min Temp (˚C)

Aver Temp (˚C)

Max RH (%)

Min RH (%)

Aver RH (%)

GF-1 22.80 18.12 20.77 83.60 65.90 72.11GF-2 23.17 20.32 21.77 84.10 67.30 73.051F-1 23.65 19.73 21.97 76.00 57.40 64.481F-2 23.44 19.19 21.84 83.80 60.20 71.522F-1 24.41 20.84 22.71 73.70 56.50 63.522F-2 23.94 20.03 22.10 81.10 62.20 70.453F-1 28.05 21.12 24.03 84.10 67.30 76.813F2 27.59 20.71 23.69 88.70 71.80 80.55

4.1.4.3 Discussion

The data loggers were put in the Law faculty library to monitor the change of

temperature and relative humidity for 7 days. Each floor was installed 2 data loggers

to collect the continuously change of temperature and relative humidity of indoor

environment.

From table 4-8, the highest temperature that achieved for library was 28.05

˚C at the third floor on Sunday evening. According to library operating time, Sunday

evening was the closing time, so, the air conditioning system will shut down for that

moment and cause the raising of the temperature of the library. Based on the

maximum temperatures were obtained of each floor, the air conditioning system able

to maintain the temperature of the library to achieve the comfort temperature.

However, the average temperatures of the Law faculty library were lower

than comfort temperature. Especially for ground floor, first floor and second floor,

37

Table 4-8: Results summary of data logger.

they were 2 ˚C to 4 ˚C lower than the comfort temperature. Therefore, the current

situations of the library for these floors were considered cool. Mean that the cooling

capacities which provide by air conditioning system were higher than the heat load

needed.

For relative humidity obtained for Law faculty library, the highest relative

humidity can be achieved was 88.70% RH. The range of the maximum relative

humidity was also very high, which were between 76% RH and 88.70% RH at

library. According to the graphs above showed that the maximum relative normally

achieved during 6 am to 7 am in the morning. This was because outdoor relative

humidity was highest during that period. From the measurements, it clearly showed

that the indoor relative humidity was strongly depend on the outdoor relative

humidity.

Besides, the average relative humidity and the minimum relative humidity

measured for library were considered high compare to the recommended relative

humidity which was 50%RH to 55%RH for libraries.

Malaysia is a hot and humid country, so, the relative humidity of the outdoor

environment is always high. It will cause the high relative humidity at indoor

environment when the fresh air is drawn in to the indoor space. Normally, the air

conditioning system designs in tropical climate were based on the seasonal country

weather data which is cool and dry. These were because no existing weather data in

tropical climate for air conditioning system design purpose used in current

commercial software.

38

By the way, the dehumidification process always been ignored in air

conditioning system design and cause high relative humidity at indoor environment.

4.2 Overview of the Existing Air-Conditioning System in

Engineering Faculty Library

4.2.1 Introduction

The Engineering Library is located at the sixth floor of the Block M

Laboratory Wing at the Faculty of Engineering. In 1985, the Library was absorbed

39

into the University of Malaya Library system. The library is opened from Monday to

Friday and the operation hours are from 8.30 am until 5.30 pm.

Engineering Library is using Fan Coil Unit (FCU) air conditioning system.

There are seven units of condensers placing on top of the roof which are air cooled

type. Above the ceiling of the library, there are three units of fan coil units which

located above the Thesis Room, Discussion Room and Reference Room respectively.

The system circulates the cool air from the FCU which transfers the heat through

refrigerant as the cooling agent. The refrigerant will be pumped to the condenser and

release the heat to the surrounding by the blowing of fan.

The Specification of Condenser:

Model MYSS 125B-FBAOS/No. MJGC3146Compressor input 12900 W/27.6 ARefrigerant R22/7.6 kgVolt/Ph/Hz 380-415/3/50Fan motor input 700 W/3.43 ACrankcase Heater 70 WControl rating 220-240 v AC

The specifications for the FCU are as follows:

FCU in Thesis Room

FCU in Discuss Room

FCU in Reference Room

Model YSB 200B YSB 250B YSB 300B

Serial No. 1772 1553 1376

Cooling Btu/Hr 200000 250000 300000

40

Specification

FCU

Table 4-9: The specifications of condenser.

Refrigerant R22 R22 R22

Charge 2 X 5.8 kg 2 X 7.8 kg 3 X 5.8 kg

Phase 3 3 3

Volt 380-420 V/50 Hz 380-420 V/50 Hz 380-420 V/50 Hz

Watt Output: 4000 W 4000 W 5500 W

Amp 8.4 A 8.4 A 11.3 A

4.2.2 Results of Engineering Faculty Library

Parameter Reading

Maximum Temperature (˚C) 26.20Minimum Temperature (˚C) 23.20Average Temperature (˚C) 25.18Maximum RH (%) 56.60Minimum RH (%) 49.00Average RH (%) 52.25Maximum CO2 (ppm) 621Minimum CO2 (ppm) 395

41

Table 4-10: The specifications of FCU.

Figure 4-24: Graph of Temperature and relative humidity of engineering faculty library compare to comfort temperature and recommended relative humidity.

Figure 4-25: Graph of CO2 concentrations of engineering faculty library compare to maximum limit of CO2 concentration.

Average CO2 (ppm) 467Maximum air flow (m/s) 0.36Minimum air flow (m/s) 0.02Average air flow (m/s) 0.10

4.2.3 Discussion

Form the graph 4-11, 85% out of the zones in the Engineering faculty library

are higher than the comfort temperature. The maximum temperature in the library

can reach until 26.2˚C. The highest temperature is 26.2˚C was found at zone 43 while

the lowest is 23.2˚C was found at zone 7. Zone 43 is located at reference room. The

high temperature is caused by the solar heat gain through the window. Another factor

contributed to this is the poor ventilation in that zone. From the zone 3 to zones 9,

these areas are placed book stacks and books. The higher volume flow rates are put

in to these areas and provide an acceptable cooling at these zones which the range of

temperature is between 23.2˚C to 24˚C. For other zones such as study area, computer

room, and rest corner, the average temperature obtained was around 25.18˚C which

higher than comfort temperature.

The range of relative humidity of Engineering faculty library is between 49%

RH and 56.60% RH. Compare the relative humidity measured to the

recommendation range of relative humidity; the relative humidity of this library is in

satisfaction range.

42

Table 4-11: Results summary of engineering faculty library.

Besides, the maximum of CO2 concentration and the minimum of CO2

concentration are 395 ppm and 671 ppm. Hence, the concentration of CO2 is lower

than the maximum limit of the standard CO2 concentration, it can be considered as

good indoor quality due to this aspect.

Next, the air flow range is between 0.02 m/s to 0.36 m/s. the average air flow

is 0.10 m/s, compare to recommendation air flow range, the results of air flow

obtained form measurement are considered acceptable.

4.2.4 Volume Flow Rate Analyzing

The same methodology which used in the Law faculty library are applied at

the Engineering faculty library. Because of some technical problem, only the off-grill

of the volume flow rate had been measured.

4.2.5 Results of the volume flow rate of the diffuser

Total Volume Flow Rate Measured (CFM) 6902 CFM

AHU cooling capacity (RT) 62.5 RT

Rated Volume flow rate (CFM) 25000 CFM

4.2.6 Discussion

43

Table 4-11: Results of the volume flow rate of the diffusers.

The total volume flow rate measured of the Engineering faculty library was

6902 CFM only. If compare to the rated volume flow rate of the fan coil units (FCU)

of the library, it only provided 27.61% of the rated volume. In this content, it means

a lot of losses occur in the system.

After investigations, the main losses due to the system were due to the

leakage of the ducting system. Following were the photos shown of the leakage of

ducting system.

4.2.7 Data Logger

44

Figure 4-26. The leakage ducts in the engineering faculty library.

4.2.8 Results summary of Engineering faculty library

LocationMax

Temp (˚C)

Min Temp (˚C)

Aver Temp (˚C)

Max RH (%)

Min RH (%)

Aver RH (%)

1 31.30 24.26 27.51 78.30 45.00 62.462 31.74 20.41 26.80 74.40 50.40 57.09

45

Figure 4-27: Graph of temperature and relative humidity of engineering faculty library. (1)

Figure 4-28: Graph of temperature and relative humidity of engineering faculty library. (2)

Table 4-12: Results summary of engineering faculty library.

4.2.9 Discussion

There was two data loggers installed in Engineering faculty library to monitor

the indoor temperature and relative humidity. One of the data loggers was installed at

the study space of the occupants and the second data logger was installed near the

book stack of the library.

According to table 4-12, the average temperatures of Engineering faculty

library were higher than comfort temperature which were 27.51 ˚C and 26.80 ˚C. It

means that the current system already can not provide the comfort temperature to the

indoor space. Maximum temperature had reached until 31.74 ˚C at Sunday evening

because the air conditioning system of library was shut down during weekend,

therefore the indoor temperature will raised up to the highest temperature. From the

minimum temperature, second data loggers had lower minimum temperature

compare to the first data logger. This was because higher volume flow rates were

provided to the book stack area.

For relative humidity measurement, the average relative humidity were

62.46% RH and 57.09% RH which still in acceptable range. From the graph 4-27and

graph 4-28, it showed that the relative humidity were higher during night time

because higher relative humidity at outdoor environment.

4.3 Chapter Summary

46

From the measurement, the temperature of Law faculty library was around

22˚C and was considered cool. The relative humidity was high in library which was

around 57.4% RH to 88.7% RH. The CO2 concentration, CO concentration and air

flow were in good conditions.

For Engineering faculty library, the temperature was higher than comfort

temperature which was around 24.26˚C to 31.30˚C. The relative humidity, CO2

concentration, CO concentration and air flow were in good conditions.

Chapter 5: Heat Load Calculation

5.1 Introduction

Heat load calculation is a method to determine the cooling capacity of the air

conditioning system. It is determined by including the heat transfer into the building

through the walls, the windows and the roof of the building. Besides, it also includes

the sensible load and latent load inside the building. The sensible load includes the

sensible heat generated by the occupants, the equipments, the lighting, infiltration

and ventilation. The latent load involves the latent head generated form occupants,

infiltration and ventilation.

5.2 Formula used for the heat load calculation

Heat gain from window

Solar:

47

Where

Q = Head gain, (Btu/hr)

A = Area, (

SHGF = Peak solar heat gain through ordinary glass, (Btu/hr. )

SC = Shading coefficient, (dimensionless)

CLF = Cooling load factor, (dimensionless)

Conductive:

Where

Q = Heat gain, (Btu/hr)

A = Area, ( )

U = Transmission coefficient, (Btu/hr. .˚F)

CLTD corrected = cooling load temperature difference, (˚F)

Heat gain for solar and trans gain from wall & roof

Where


48

A = Area, ( )

U = Transmission coefficient, (Btu/hr. .˚F)

CLTD corrected = Equivalence temperature different, (˚F)

Heat gain due to occupancy

Where


n = Number of occupant, (dimensionless)

Qs = Sensible heat gain of occupant, (Btu/hr)

Ql = Latent heat gain of occupant, (Btu/hr)Library is categorized in low degree activity group therefore it is more on

seated and very light work.

Heat gain due to lighting

Where Q = Heat gain from lighting

W = Total lamp Wattage

BF = ballast factor

N = Total number of lamps

49

For florescent lamps, W= 36 watts

Heat gain due to equipment

Electricity equipments are the other sources of heat generated in air conditioned

space. Heat generated due to the less efficiency of the electricity equipment

especially in office, hospital, and library. Thus, the heat load due to equipments can

be calculated by using ASHRAE tables and standards 1997-28.

Cooling load due to ventilation

To control the comfort level, it is necessary to control the rate and location of

ventilation air entering the building. It can be accomplished through forced

ventilation where a fan provides a predictable and constant of outdoor air intake into

the building.

Base on the table Outdoor Air Requirements for Ventilation (institution facilities):

Application Estimated Max Occupancy,

P/1000

Outdoor Air Requirement

CFM/person L/s.person

Libraries 20 15 8

The sensible and latent cooling load can be calculated by using the following equation:

= 1.08(CFM)(∆T)

50

= 4800(CFM)(∆W)

Where,

5.3 Calculation and Discussion

5.3.1 Heat Load Calculation of Law faculty library

CONDITIONS DB WB %RH GR./ LB

OUTDOOR (OA) 95 84.2 70 177

ROOM (RM) 73.4 62.6 55 66.5

DIFERRENCE 21.6 - - 110.5

51

= Sensible heat

= Latent heat

BF = Ballast factor

∆T = Temperature change

∆W = Humidity ratio of air change

Table 5-1: Temperature difference calculations from peak outdoor conditions.

5.3.1.1 Heat Load Calculation for Ground Floor

Sensible heat gainConduction Surface-facing Area/Ft2 U CLTD corrected Btu/hr

Roof 0 0 0 0Wall(N) 454.35 0.48 18.5 4034.614Wall(E) 1155.84 0.48 28.25 15673.17Wall(S) 1242.70 0.48 18.5 11035.21Wall(W) 1190.93 0.48 23.05 13176.44Glass(N) 1060.15 1.04 21.1 23263.85Glass(E) 358.66 1.04 22.4 8355.261Glass(S) 271.79 1.04 19.15 5412.99Glass(W) 323.57 1.04 22.4 7537.79

Subtotal 88489.32SolarGlass-Facing Area/Ft2 SHGF SC CLF Btu/hrGlass(N) 1060.15 39 0.45 0.72 13396.01Glass(E) 358.66 231 0.45 0.29 10811.88Glass(S) 271.79 44 0.45 0.55 2959.804Glass(W) 323.57 231 0.45 0.3 10090.4

Subtotal 37258.09

Internal sensible heatItem Quantity Btu/hr/person Btu/hrOccupants 80 230 18400Electrical Appliances Quantity Watt Factor 1 W=3.4Btu/hr Btu/hrLights 402 36 1.25 3.4 61506Computer 10 350 1.25 3.4 14875 subtotal 94781Infiltration Item Delta T Constant CFM Btu/hrDoor 21.6 1.09 500 11772

Ventilation

52

Table 5-2: Heat load calculations for ground floor of the Law faculty library.

Item Quantity CFM/person CFM Btu/hrOccupant 80 18 1440 33903.36

Sensible Subtotal 266203.8Latent heat gain

Source Quantity Btu/hr/person Btu/hrOccupants 80 190 15200 CFM infiltration 500 37570ventilation 1440 108201.6

Latent Subtotal 160971.6

Total 427175.4

5.3.1.2 Heat Load Calculation for First Floor

Sensible heat gainConduction

Surface-facing Area/Ft2 UCLTD

correctedBtu/hr

Roof 0 0 0 0Wall(N) 1007.73 0.48 18.5 8948.60Wall(E) 1034.64 0.48 28.25 14029.66Wall(S) 1017.95 0.48 18.5 9039.41Wall(W) 1069.73 0.48 23.05 11835.45Glass(N) 385.57 1.04 21.1 8460.87Glass(E) 358.66 1.04 22.4 8355.26Glass(S) 375.34 1.04 19.15 7475.28

53

Table 5-2: Heat load calculations for ground floor of the Law faculty library. (continued)

Glass(W) 323.57 1.04 22.4 7537.79 Subtotal 75682.33

Solar Glass-Facing Area/Ft2 SHGF SC CLF Btu/hrGlass(N) 385.57 39 0.45 0.72 4872.02Glass(E) 358.66 231 0.45 0.29 10811.88Glass(S) 375.34 44 0.45 0.55 4087.46Glass(W) 323.57 231 0.45 0.3 10090.40

Subtotal 29861.76Internal sensible heat

Item Quantity Btu/hr/person Btu/hrOccupants 80 230 18400Electrical Appliances Quantity Watt Factor 1 W=3.4Btu/hr Btu/hrLights 398 36 1.25 3.4 60894Computer 12 350 1.25 3.4 17850

subtotal 97144Infiltration Item Delta T Constant CFM Btu/hrDoor 21.6 1.09 500 11772

Ventilation Item Quantity CFM/person CFM Btu/hrOccupant 80 18 1440 33903.36

Sensible Subtotal 248363.45

Latent heat gainSource Quantity Btu/hr/person Btu/hrOccupants 80 190 15200

CFM infiltration 500 37570ventilation 1440 108201.6


Total 409335.05

54

Table 5-3: Heat load calculations for first floor of the Law faculty library.

Table 5-3: Heat load calculations for first floor of the Law faculty library. (continued)

5.3.1.3 Heat Load Calculation for Second Floor


Surface-facing Area/Ft2 U CLTD corrected Btu/hrRoof 0 0 0 0.00Wall(N) 1007.73 0.48 18.5 8948.60Wall(E) 1034.64 0.48 28.25 14029.66Wall(S) 1017.95 0.48 18.5 9039.41Wall(W) 1069.73 0.48 23.05 11835.45Glass(N) 385.57 1.04 21.1 8460.87Glass(E) 358.66 1.04 22.4 8355.26Glass(S) 375.34 1.04 19.15 7475.28Glass(W) 323.57 1.04 22.4 7537.79


Subtotal 29861.76

Internal sensible heatItem Quantity Btu/hr/person Btu/hrOccupants 80 230 18400.00Electrical Appliances Quantity Watt Factor 1 W=3.4Btu/hr Btu/hrLights 394 36 1.25 3.4 60282.00Computer 10 350 1.25 3.4 14875.00

subtotal 93557.00Infiltration Item Delta T Constant CFM Btu/hr

Door 21.6 1.09 500 11772.00

55

Table 5-4: Heat load calculations for second floor of the Law faculty library.



Latent heat gainSource Quantity Btu/hr/person Btu/hrOccupants 80 190 15200.00 CFM infiltration 500 37570.00ventilation 1440 108201.60


Total 405748.05

5.3.1.4 Heat Load Calculation for Third Floor


Surface-facing Area/Ft2 UCLTD

correctedBtu/hr

Roof 1616.04 0.2 56.2 18164.29Wall(N) 873.61 0.48 18.5 7757.62Wall(E) 900.52 0.48 28.25 12211.00Wall(S) 883.83 0.48 18.5 7848.43Wall(W) 935.61 0.48 23.05 10351.55Glass(N) 385.57 1.04 21.1 8460.87Glass(E) 358.66 1.04 22.4 8355.26

56

Table 5-4: Heat load calculations for second floor of the Law faculty library. (continued)

Glass(S) 375.34 1.04 19.15 7475.28Glass(W) 323.57 1.04 22.4 7537.79



Item Quantity Btu/hr/person Btu/hrOccupants 80 230 18400.00Electrical Appliances Quantity Watt Factor 1 W=3.4Btu/hr Btu/hrLights 402 36 1.25 3.4 61506.00Computer 20 350 1.25 3.4 29750.00

subtotal 109656.00Infiltration Item Delta T Constant CFM Btu/hrDoor 21.6 1.09 500 11772.00





Total 416162.53

5.3.1.5 Result Summary of Heat Load calculation for Law Faculty library

57

Table 5-5: Heat load calculations for third floor of the Law faculty library.

Table 5-5: Heat load calculations for third floor of the Law faculty library. (continued)

FloorTotal Heat Gain

(Btu/hr)

Design Cooling

Capacity (Btu/hr)

Volume flow

rate per area

(cfm/ft2)

GF 427175.38 1020000 58

1F 409335.05 875000 50

2F 405748.05 870000 50

3F 416162.53 1090000 62

5.3.1.6 Discussion

From the table 5-6, the total heat gains of Law faculty library were 427175.38

Btu/hr, 409335.05 Btu/hr, 405748.05 Btu/hr and 416162.53 Btu/hr at ground floor,

first floor, second floor and third floor respectively. Compare the results between

each floor; the ground floor had the highest total heat gain among each floor in the

Law faculty library. The reason was ground floor was the main entrance of the

library; all the students and staffs were going in and out from library through the

door at ground floor, so, high infiltration loss at the main entrance due to high

frequency of door opening. Therefore, this situation will increase the cooling load of

the indoor environment because cool air was transfer out from the building.

Secondly, the calculations also showed that the third floor of the library had

higher total heat gain, which was 416162.53 Btu/hr compare to first floor and second

floor of the library. This was because third floor is the top floor in Law faculty

library, the extra heat gains of this floor are come from the roof of the library.

Besides, there is management office and computer corner at this floor. Therefore,

58

Table 5-6: The results summary of total heat gains and design cooling capacities for Law faculty library.

third floor consists of higher number of computers; it also contributed heat gain to

the indoor environment. Thus, heat load of third floor was higher than first floor and

second floor.

Furthermore, the heat gain of first floor was 409335.05 Btu/hr and the heat

gain of the second floor was 405748.05Btu/hr from the calculations. The total heat

gain of first floor and second floor were lower than ground floor and third floor

because they had no cooling loss for door infiltration and heat gain from roof top.

There were also varies design cooling capacities were recorded. The cooling

capacities recorded were 1020000 Btu/hr, 875000 Btu/hr, 870000 Btu/hr and

1090000 Btu/hr for ground floor, first floor, second floor and third floor respectively.

Basically, the design cooling capacities of the Law faculty library were based on rule

of thumbs calculations. Normally, the volume flow rate needed for indoor space per

square feet is 50 cfm/ft2. From table 5-6, it showed the volume flow rate per square

feet of the library were 58 cfm/ft2 , 50 cfm/ft2 , 50 cfm/ft2 , and 62 cfm/ft2 from

ground floor to third floor. There were higher design cooling capacity at ground floor

and third floor because of extra heat gain at these floors.

Compare the total heat gain to the design cooling capacities, the percentage of

heat gain over the design cooling capacities of each floors were 41.88%, 46.78%,

46.63% and 38.83% for ground floor, first floor, second floor and third floor

respectively. From the calculations above, it showed that the safety factor of cooling

capacities design was two. Mean that the air conditioning system at the Law faculty

library was oversize for 2 times larger. The purpose for over sizing the design

cooling capacities was to maintain the comfort indoor environment in future. Due to

59

the unexpected change of the climate and the additional internal and external heat

gain, over sizing the air conditioner system was to make sure the recommended

indoor quality are achieved. Besides, the decay of the performance and efficiency of

the air conditioning system, it also became a consideration factor in designing the

cooling capacities of the air conditioning system. Therefore, to have a clear picture of

the trend of indoor quality profile and the sustainability of the air conditioning

system in future, the TRNSYS simulation software was used to simulate the

temperature and relative humidity profile of the indoor environment of library based

on the latest climate weather profile. The TRNSYS simulation will discuss detail in

the following chapter.

5.3.2 Heat Load Calculation for Engineering faculty library


Surface-facing Area/Ft2 U

CLTD corrected Btu/hr

Roof 11998 0.2 56.2 134857.52Wall(N) 348.00 0.415 18.5 2671.77Wall(E) 250.00 0.415 28.25 2930.94Wall(S) 303.00 0.415 18.5 2326.28Wall(W) 194.00 0.415 23.05 1855.76Glass(N) 723.00 1.04 21.1 15865.51Glass(E) 379.00 1.04 22.4 8829.18Glass(S) 605.00 1.04 19.15 12049.18

60

Glass(W) 416.00 1.04 22.4 9691.14 Subtotal 56219.76

SolarGlass-Facing Area/Ft2 SHGF SC CLF Btu/hrGlass(N) 723.00 39 0.45 0.72 9135.83Glass(E) 379.00 231 0.45 0.29 11425.14Glass(S) 605.00 44 0.45 0.55 6588.45Glass(W) 416.00 231 0.45 0.3 12972.96


Item Quantity Btu/hr/person Btu/hrOccupants 100 230 23000.00Electrical Appliances Quantity Watt Factor 1 W=3.4Btu/hr Btu/hrLights 294 36 1.25 3.4 44982.00Computer 15 350 1.25 3.4 22312.50Photocopier 1 1553 1.25 3.4 6600.25

subtotal 90294.50Infiltration Item Delta T Constant CFM Btu/hrDoor 21.6 1.09 500 11772.00





Total 470179.84

5.3.2.1 Result Summary of Heat Load calculation for Law Faculty library

61

Table 5-7: Heat load calculations for the Engineering faculty library.

Table 5-7: Heat load calculations for the Engineering faculty library. (continued)

LocationTotal Heat Gain

(Btu/hr)

Design Cooling

Capacity (Btu/hr)

Volume flow

rate per area

(cfm/ft2)

Engineering

faculty

library

470179.84 750,000 62

5.3.2.2 Discussion

From the table 5-8, the total heat gain of the Engineering faculty library was

470179.84 Btu/hr. There were 3 FCU provided cooling capacities to the library. The

design cooling capacities of the each FCU were 300000 Btu/hr, 250000 Btu/hr and

200000 Btu/hr respectively. Hence, total design cooling capacity was 750000 Btu/hr.

Compare between the total heat gain of single floor at Law faculty library and

the total heat gain of Engineering faculty library, it shown that the total heat gain of

the Engineering faculty library is higher than the total heat gain of single floor at

Law faculty library. This was because the fraction of window to the wall of

Engineering faculty library is higher than the fraction of window to the wall of Law

faculty library. By this ways, more solar heat was transfer in the indoor environment

of the Engineering faculty library. Therefore, the total heat gain of the Engineering

faculty library is higher than the total heat gain of the Law faculty library.

The percentage of the total heat gain over the design cooling capacity is

62.69%. For this study purpose, some assumptions need to make. First, performance

62

Table 5-8: The result summary for the Engineering faculty library.

of the air conditioning system was assumed to be constantly decayed through out the

years. The efficiency of the air conditioning system also assumed as 100%

efficiency.

Hence, based on the calculations, the cooling load need was 62.69% of the

total design cooling capacity, mean that as long as the decreasing of the performance

of the air conditioning system do not more than 40% of the total design cooling

capacity, the system still can provide the comfort indoor environment for the

Engineering faculty library.

However, the climate change of the outdoor environment gives a big impact

to the indoor total heat gain. Besides, the change of the indoor environment also will

affect the total heat gain. The following simulation chapter will discuss about the

indoor environment in future taken into account of climate change impact.

5.4 Chapter summary

From the heat load calculations for Law faculty library, the percentage of

heat gain over the design cooling capacities of each floors were 41.88%, 46.78%,


respectively. For Engineering faculty library, the percentage of heat gain over the

design cooling capacities was 62.69%.

63

Heat load calculation can not use to estimate and predict the future conditions

of the libraries, it only used to compare between the heat load and the design cooling

capacities.

Chapter 6: TRNSYS Simulation

6.1 Introduction to TRNSYS Simulation Studio

TRNSYS (Transient System Simulation Program) is a complete and extensible

simulation environment for the transient simulation of systems, including multi-zone

buildings. Engineers and researchers around the world are using this program to

validate new energy concepts, from simple domestic hot water systems to the design

64

and simulation of buildings and their equipment, such as control strategies, occupant

behavior, alternative energy systems (wind, solar, photovoltaic, hydrogen systems),

etc. The modular structure and DLL-based architecture of TRNSYS allows users and

third-party developers to easily add custom component models, using all common

programming languages (C, C++, PASCAL, FORTRAN, etc.).

To create a TRNSYS project, it is typically setup by connecting modules

graphically in the Simulation Studio. Each type of module is described by a

mathematical model in the TRNSYS simulation engine and has a set of matching

Proforma's in the Simulation Studio. The proforma has a black-box description

which processes the inputs to produce outputs and passes the output to another

module for further calculation.

6.2 Simulation of Weather for Tropical climate

6.2.1 Introduction

Before looking into the indoor environment quality, the main concern is the

trend of the ambient conditions. In this research, how the impact of the ambient

conditions to the indoor environment quality become a very important aspect here.

65

Therefore, the weather of the tropical climate was generated by using

TRNSYS Simulation and the profile of the ambient temperature and the ambient

relative humidity were shown in the figure below. The forecast of the weather were

based on the weather data of Kuala Lumpur. Following graph are the ambient

temperature and ambient relative humidity simulation for year 2000, year 2020 and

year 2050.

66

Figure 6-1: Graph of ambient temperature and relative humidity at year 2000.


6.2.2 Discussion

YearMax

Temp, (˚C)

Min Temp,

(˚C)

Aver Temp,

(˚C)

Max RH (%)

Min RH, (%)

Aver RH, (%)

2000 35.30 20.85 27.16 100.00 40.50 81.87

2020 36.10 21.81 28.13 99.00 37.50 80.71

2050 37.42 22.69 29.22 99.00 22.69 78.72

67


Table 6-1: Summary of outdoor conditions.

From the table 6-1, it showed that the average temperature and average

relative humidity were 27.16˚C and 81.87˚C during year 2000. Mean that the tropical

climate is hot and humid. Besides, from the weather forecasting, the temperature will

increase around 1˚C for next 20 years and the relative humidity will decrease around

1% to 2% for next 20 years.

Therefore, the increasing of temperature and the decreasing of relative

humidity in future from the weather forecasting will affect the current installed air

conditioning system. The increasing temperature will be concern because it affect the

determination of extra cooling capacity need to add to maintain the comfort

environment in the building.

6.3 Simulation of Law Faculty Library

6.3.1 Layout of TRNSYS model for Law faculty library

68

Turn

RadiationWeather data

Psychrometrics

Sky temp

Law Library GF Temperature Plotter

Air Change Controller

Heat Gain Controller

Psychrometrics-2

Psychrometrics-3

FanAir Mixer Psychrometrics-4 Cooling Coil Psychrometrics-5

WCPCooling Tower Pump Energy Transfer Plotter

Air Mixer controller

Figure 6-4: Layout of TRNSYS model for ground floor.

69

Turn


Psychrometrics

Sky temp

Law Library 1F Temperature Plotter



Psychrometrics-2

Psychrometrics-3




Figure 6-5: Layout of TRNSYS model for first floor.

Turn


Psychrometrics

Sky temp




Psychrometrics-2

Psychrometrics-3




Figure 6-6: Layout of TRNSYS model for second floor.

Note: The AHU does not found in TRNSYS studio, the combining of cooling coil and WCP is

assumed to represent the AHU of Law faculty library.

6.3.2 Description of modules used in TRNSYS simulation studio

Module Type Description Inputs and outputs


Air Change Controller; control the fresh air intake.

Inputs: Air flow rate.

Outputs: Air change of the building.

Air Mixer

Air Mixer; mixing the return air from building and the

fresh air from ambient then supply to cooling coil.

Input: Return air temperature and humidity ratio, fresh air temperature and humidity ratio, Total air flow rate.

70

Turn


Psychrometrics

Sky temp




Psychrometrics-2

Psychrometrics-3




Figure 6-6: Layout of TRNSYS model for third floor.

Table 6-2: Modules type description.

Output: Mixing air temperature and humidity ratio, Air flow rate.


Air Mixer Controller; control the percentage of fresh air

intake.

Input: Percentage of the fresh air.

Outputs: Control signal.

Building -Type-56b

Multi-zone building; This component models the thermal behaviour of a

building.

Inputs: Ventilation air temperature and relative humidity

Outputs: Room temperature and relative humidity.

Cooling Coil

Cooling Coil; cool the mixing air to the desire off-coil

temperature.

Input: Mixing air dry bulb temperature, wet bulb temperature and air flow rate.

Output: Mixing air dry bulb temperature, wet bulb temperature and air flow rate.

Cooling Tower

Cooling Tower; transfer the heat from the system to the

ambient

Input: Ambient dry bulb temperature and wet bulb temperature, cooling water temperature and flow rate.

Output: Sump temperature and flow rate.

Energy Transfer Plotter

Online plotter; display the simulation result on monitor.

Inputs: Sensible cooling rate, latent cooling rate, total cooling rate and chiller heat rejection

Outputs: Sensible cooling rate, latent cooling rate, total cooling rate and chiller heat rejection profile on screen.

Fan

Fan; blow the air into the thermal zones of building.

Input: Air dry bulb temperature, relative humidity and air flow rate.

71

Table 6-2: Modules type description. (continued)

Output: Air dry bulb temperature, relative humidity and air flow rate.


Heat Gain Controller; set the number of occupants and computer inside the building.

Input: Number of occupants and number of computer.

Output: Control signal.

Psychrometrics-1

Psychrometrics calculator; calculates the rest of the moist air properties with two properties given.

Inputs: Ambient temperature and ambient relative humidity.

Outputs: The rest of the moist air properties.

Psychrometrics-2


Inputs: Ambient temperature and relative humidity.


Psychrometrics-3


Inputs: Return air temperature and relative humidity.


Psychrometrics-4


Inputs: Air mixer temperature and humidity ratio.


Psychrometrics-5


Inputs: Off-coil dry bulb temperature and wet bulb temperature.


Pump

Pump; circulate the cooling water from air conditioner system to cooling tower.

Input: Cooling water temperature and flow rate.

Output: Cooling water temperature and flow rate.

72



Radiation

Radiation; direct ambient conditions affect to the building.

Input: Ambient conditions.


Sky temp

Sky Temperature; provides the frictive sky temperature.

Input: beam radiation on horizontal and sky diffuse radiation on horizontal.

Output: Beam radiation on the horizontal and diffuse radiation on the horizontal.

Temp & RH Plotter

Online plotter; display the simulation result on monitor.

Inputs: Room temperature and relative humidity.

Outputs: Room temperature and relative humidity profile on screen.

Turn

Building Position Controller; Control the position of the building.

Input: the position angle of the building.


WCP

Water Cool package air conditioning system; provides the cooling capacity to cool the air in the cooling coil.

Input: Temperature and flow rate.

Output: temperature and flow rate

Weather data

Weather Data Processor; Combines data reading, radiation processing and sky temperature calculations

Inputs: None

Outputs: Ambient dry and wet bulb temperature, humidity ratio, relative humidity, wind velocity, total horizontal radiation, etc.

6.3.3 Air Change Rate (ACH) Calculator Module

(1/hr)

73

where

V = Volume of zone, (m3)

6.3.4 AHU Cooling coil dimension

Area = Height x width

= 1.34 m x 2.20 m

= 2.95 m

Number of rows = 4

Number of circuits = 44

6.3.5 Assumption

The assumption were made was to simplify the simulation. There is a lot of

uncertainty for the actual situation; however, reasonable assumption will be made to

make sure the simulation results are as close as the actual situations. Following are

the assumption made:

1. Air volume flow of inlet AHU is 100% blow into the indoor of building.

2. The performance of the air conditioning system is ideal through out the

years.

74

3. There is 20% fresh air of the air conditioning system.

4. The air volume flow rates are equally distributed to each zone in the building.

5. The pumps, fans and cooling tower are performing 100% efficiency.

6. All the conditions of indoor environment remain the same in future.

6.3.6 Results

75

Figure 6-7: Minimum part load to achieve comfort temperature simulation of law faculty library for year 2000.



6.3.7 Results summary

Floor

Design Cooling capacity.

RT

Minimum load needed, RT (Year 2000)



GF 85 47 53 601F 72.9 38 41 452F 72.5 33 35 383F 90.8 43 46 49

FloorPart load to achieve comfort temperature

at year 2000 (%)

Part load to achieve comfort temperature

at year 2020 (%)

Part load to achieve comfort temperature

at year 2050 (%)GF 55.29 62.35 70.591F 52.13 56.24 61.732F 45.52 48.28 52.413F 47.36 50.66 53.96

Floor

Percentage of part load increasing from

year 2000 to year 2020 (%)

Percentage of part load increasing from

year 2000 to year 2050 (%)

GF 7.06 15.291F 4.12 9.602F 2.76 6.903F 3.30 6.61

76

Table 6-3: Minimum cooling load to achieve comfort temperature of law faculty library at year 2000, year 2020 and year 2050.

Table 6-4: Part load to achieve comfort temperature of law faculty library at year 2000, year 2020 and year 2050.

Table 6-5: Percentage of part load increasing of law faculty library.

6.3.8 Discussion

To study the sustainabilty of the air conditioning system and how the climate

change impact on it, the worst indoor conditions were taken into considerations.

By simulation, the maximum temperature which higher than comfort

temperature was identified. Then, minimum part load for worst case to achieve

comfort temperature at year 2000, year 2020 and year 2050 were identified. With the

part load identified, the percentage increasing of cooling load due to the impact of

climate change on the indoor environment of Law faculty library can be calculated.

Table 6-4 showed the part load to acheieve the comfort temperature were

55.25%, 52.13%, 45.52% and 47.36% for ground floor, first floor, second floor and

third floor respectively at year 2000. From the simulation, the current situations only

need 50% of the design cooling capacity to provide comfort environment.

From table 6-5, the percentage increasing of part loads were 7.06%, 4.12%,


respectively from year 2000 to year 2020. Besides, the percentage increasing of part

loads were 15.29%%, 9.60%, 6.90% and 6.61% for ground floor, first floor, second

floor and third floor respectively from year 2000 to year 2050. It showed that the

climate change will affect the part load around 2% to 4% ecept for ground floor for

next 20 years. Ground floor had the hihgest increasing of part load which was 7.06%

for next 20 years because the fraction of glass window to wall of ground floor is high

compare to other floor. Therefore, higher solar heat gain and radiation heat gain

transfer into the indoor environment through the glass window.

77

Table 6-6: Modules type description.

6.4 Simulation of Engineering faculty Library

6.4.1 Layout of TRNSYS model of Engineering faculty library

Note: The FCU of Engineering faculty library does not found in TRNSYS studio, so,

the combining of cooling coil and FCU is assumed to represent the FCU and

condensers of actual situation.

6.4.2 Description of modules used in TRNSYS simulation studio

FCU

Fan Coli Unit air conditioning system; provides the cooling capacity to cool the air in the cooling coil.

Input: Temperature and flow rate.

Output: temperature and flow rate.

78

Turn


Psychrometrics

Sky temp

Engine Library Temperature Plotter



Psychrometrics-2

Psychrometrics-3


Energy Transfer Plotter


FCU

Figure 6-8: Layout of TRNSYS model of engineering faculty library

6.4.3 Assumption

For study purpose, some assumptions need to make to simplify the complex

actual situation.

1. 100% of air volume flow of inlet FCU is blowing into the indoor of building.

2. The performance of the air conditioning system is ideal through out the

years.

3. There is 20% fresh air of the air conditioning system.

4. The air volume flow rates are equally distributed to each zone in the building.

5. The fans are performing 100% efficiency.

6. All the indoor conditions do not change in future.

6.4.4 Results

79

Figure 6-9: Minimum part load to achieve comfort temperature simulation of engineering faculty library for year 2000.

80



6.4.5 Results summary

Location

Design Cooling capacity.

RT




Engineering library

62.5 46 50 55

Location

Part load to achieve comfort temperature at

year 2000 (%)


year 2020 (%)


year 2050 (%)

Engineering library

73.60 80.00 88.00

Location

Percentage of part load increasing

from year 2000 to year 2020

(%)

Percentage of part load increasing

from year 2000 to year 2050

(%)Engineering

library6.40 14.40

81

Table 6-7: Minimum cooling load to achieve comfort temperature of engineering faculty library at year 2000, year 2020 and year 2050.

Table 6-8: Part load to achieve comfort temperature of engineering faculty library at year 2000, year 2020 and year 2050.

Table 6-9: Percentage of part load increasing of engineering faculty library.

6.4.6 Discussion

According to table 6-8, the part load of air conditioning system in

Engineering faculty library to achieve comfort temperature were 73.60%, 80.00%

and 88.00% at year 2000, year 2020 and year 2050 respectively.

From table 6-9, the percentage increasing of part load form year 2000 to year

2020 was 6.40% and the percentage increasing of part load was 14.40% from year

2000 to year 2050 due to the impact of climate change.

Compare the percentage increasing of part load between Law faculty library

and Engineering faculty library for next 20 years, the results showed the percentage

increasing of part load of Engineering faculty library which around 6.40% was

higher than percentage increasing of part load of Law faculty library which around

2% to 4%. This is because the glass window to wall fraction of Engineering faculty

library is high compare to the glass window to wall fraction of Law faculty library.

The glass window to wall fraction of Engineering faculty library is around 75% and

the glass window to wall faction of Law faculty library is just around 25%.

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6.5 Chapter summary

By TRYSYS simulation, the impact of climate change to the indoor

environment at Law faculty library is just around 2% to 4% of its design cooling

capacities for next 20 years provide that the air conditioning system is in ideal

condition. However, the ground floor had higher impact by climate change which is

around 7% increasing of part load for next 20 years because the high glass window to

wall fraction.

Due to higher fraction of glass window to wall, the increasing of part load at

Engineering faculty library is around 7% for next 20 years.

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Chapter 7: Conclusion and Future Work

7.1 Conclusion

First of all, the field work was carried out at Law faculty library and

Engineering faculty library. The parameters measured were temperature, relative

humidity, CO2 concentration, CO concentration, air flow, and volume flow rate.

Found that the temperature was lower than comfort temperature and the relative

humidity was high in the library. Other parameters such as CO2 concentration, CO

concentration, air flow were fulfilled the ASHRAE Standard. On the other hand,

Engineering faculty library had higher temperature than comfort temperature.

Relative humidity, CO2 concentration, CO concentration and air flow were in

acceptable condition.

Secondly, heat load calculation is used to calculate the design cooling

capacities and can not use to estimate and predict the future conditions of the

libraries. From the heat load calculation at chapter 5, it showed the total heat gain

needed for Law faculty library only around 50% of the design cooling capacities.

Mean that, the safety factor used in cooling capacities design was two. On the other

hand, the percentage of total heat gain over the design cooling capacities of the

Engineering faculty library was 62.69%.

To have a clear picture of the impact of climate change on the building in

future, the TRNSYS simulation is needed. Due to the complexity of the actual

situations, some assumptions were made to simplify the situations for the study

84

purpose. By TRYSYS simulation, the results showed only 2% to 4% part load had

increased due to the impact of climate change to the indoor environment at Law

faculty library for next 20 years. However, the ground floor had higher impact by

climate change which is around 7% increasing of part load for next 20 years because

the high glass window to wall fraction. Besides, part load of Engineering faculty

library will increase around 7% for next 20 years due to higher fraction of glass

window to wall.

As a conclusion, the climate change will be one of the factors to affect the

indoor environment. It will gives impact and increases part load of the buildings

around 2% to 7% in hot and humid tropical climate country for next 20 years.

7.2 Recommendation and Future Work

The sustainability of the air conditioning system depends on a lot of factors

such as the system design, system maintenance, location and also climate change.

There are no monitoring systems for air conditioning system in both of libraries. For

more accuracy of research, the monitoring devices need to put at the field work site

to monitor the system for a certain periods.

Due to lack of WCP and FCU air conditioning system in TRNSYS studio,

create the new modules for this two systems are needed. The comparison of

TRNSYS simulation results with the performance curve of actual situations needed

to carry out to verify the result of simulations.

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