Download Effective Room sensible Heat

DESIGN, SELECTION, INSTALLATION AND COMMISSIONING OF CLEAN
ROOM AND HVAC FACILITY FOR ARCHIVES BUILDING
1
D.ANURADHA, 2D.DAMODARA REDDY, 3Dr.P.H.V.SESHATALPASAI
M.Tech Student of Dept of Mechanical, MRCET Hyderabad, Telangana-India ,[email protected]
2
Associate Professor, 3HOD, MECHANICAL Dept, MRCET, Hyderabad, Telangana-India
1
Abstract:- Climate control in archives can be managed
very differently from other buildings, but very often
standard technology, and reliance on standard
specifications is applied. This article is a re-investigation
of how best to control the climate in archives, based on
the chemistry of decay and the physics of the
atmosphere, at first discarding the pedantic strictness of
the archival standards but paradoxically showing that
they can indeed be attained by very simple means
The archives and rare books rooms in the basement
were previously served by a relatively new heating,
ventilating, and air conditioning (HVAC) system
generally independent from the balance of the building.
This system had several problems, the greatest of which
was the reliance on campus steam for reheat. Since the
steam is not available at the building in summer, no
positive dehumidification was provided, leading to high
humidities, puckering book leaves, and some mold. This
was compounded by problems with the dedicated
humidifier serving this area, inadequate filtration, the
threats from overhead piping, and subsurface water
seepage.
The library undertook a plan to improve the HVAC
systems and to provide better protection of the collection
from building systems risks. Among the several
alternatives considered by the library, the option with
the highest probability of success and very modest cost
was to provide new, dedicated HVAC systems to serve
the special collections areas. Unlike the original systems,
the new systems were designed for dehumidification,
using their own condenser heat for reheat, without
relying on the campus
This project work has been intended to suggest a
suitable clean room facility and comfort air conditioning
design for the various public areas and rooms of a
proposed .Develop a simplified Archives building
HVAC system which could predict the temperature
variation within the building and estimate the amount of
energy required to get the comfort level using. For the
estimation, this model would take into account of
different physical properties of Archives building,
location of Archives building, weather, gains and
heating system. As a case study, the model has been
implemented to a semi-detached dwelling with all the
real data. then compared with another software which is
verified against Archives Building Energy Simulation
Test (Archives) building load and HVAC tests. The main
advantage of this model is its simplicity and less
computational resources
I.
INTRODUCTION:
CLEANROOM
Effective contamination control is the principal reason to
operate a cleanroom. Because the purpose of a cleanroom is
to control the concentration of airborne particles to
minimize undesired existence of particles inside the
cleanroom, and to maintain certain environmental
conditions environmental systems (HVAC systems)
designed for cleanrooms are extremely energy intensive
compared to their counterparts in commercial buildings.
Some industries use production metrics such as watts per
unit of product, which focus on overall production
efficiency but overlook the efficiency of energy intensive
environmental systems. Since energy generally represents a
significant operating cost for cleanroom facilities,
improving energy efficiency in cleanrooms can contribute to
significant cost savings.
HVAC
The main objective of comfort air conditioning is to provide
building occupants with a comfortable, safe and healthy
indoor environment. The benchmark for comfort, safety,
health and indoor air quality varies depending on the
building use such as
· Commercial: Office buildings, supermarkets, shopping
malls, restaurants etc.
· Institutional: Recreation centers, theaters, indoor stadia,
schools, museums etc
·
Residential: Hotels, private homes, low or high rise
residential buildings
· Health Care Facilities: Hospitals, nursing homes etc
1.
PURPOSE
HVAC is important in the design of medium to large
industrial and office buildings such as skyscrapers and in
marine environments such as aquariums, where safe
and healthy building conditions are regulated with respect to
temperature and humidity, using fresh air from outdoors.
2. SCOPE
This specification defines the requirements for the design,
engineering, assembly fabrication, procurement, testing,
balancing and installation and commissioning for
satisfactory performance of Heating, Ventilating and Air
Conditioning (HVAC)
3.
Design Concepts
DESIGN REQUIREMENTS
Internal Heat Gains
The internal (equipment) heat dissipation loads shall be
verified and confirmed by the HVAC contractor when
sizing the AC equipment. For the equipment sizing
purposes, the contractor shall consider heat dissipation from
the electrical equipment as well as lighting in the space. To
estimate the total cooling required, the total internal heat
gains will then be added to heat transmission gains through
exterior walls/roof and heat gains from ventilation air
(outdoor air).
Indoor Design Conditions
The scope of the work described in this specification shall
include complete HVAC systems as specified herein. The
VENDOR shall provide all supervision, pressure test,
performance test, material, equipment, machinery and all
other items necessary to complete the HVAC systems. Any
material not specifically mentioned in this specification but
required for proper performance and operation shall be
furnished and installed by the VENDOR. Vendor shall
install all the items as required for complete system.
The main purpose of clean room and hvac facilities are to
supply sufficient amount of air, which should maintain
correct temperature, humidity, air purity, air movement and
noise level. Occupant’s feels quite comfort in a selected
enclosure by maintaining all the factors correctly. The high
capacity requirements suggest the selection of air handling
units and require high efficiency filters.
Design Conditions
Outdoor Design Conditions
• Ambient design conditions: 50.0°C DB/30.0°C WB (for
cooling load calculations)
• 50.0°C DB (for air cooled condensing unit selection)
• Winter Design conditions: 5°C DB
Note:
1. Equipment shall continue operating up to 50°C ambient
temperature, without failure.
2. In case of failure of one (1) unit a temperature of 32°C
can be maintained inside the rooms.
Indoor Design Conditions
Room Summer Max (°C) Winter Min°C RH (%)
Control Room 22° 22° 60
Heat Dissipation
Light Heat Dissipation
Lighting heat dissipation for various rooms shall be
considered. If lighting data is not available, below figure can
be applied:
1. Design Calculations
The bases for determining the heating load are the constant
average temperature for winter nights and any continuous
supply of heat present at all times. The quantity of heat
accumulated by the building must be taken into
consideration as well as the energy of any cooling
equipment.
2. Method for Estimating Heating Load
The normal process for estimation of heat load is as follows:
a. Carry out an assessment of the weather
conditions prevailing outside the building,
including humidity, temperature, path of
wind and speed.
b. Determine the desirable inside air
temperature to be maintained.
c. Assess the temperature in adjoining
locations which are not heated.
d. Choose
the
coefficient
of
heat
transmission.
e. Establish the outside areas by which heat
is dissipated.
f. Estimate the losses by heat transference
from glass, bricks, and base in the
building.
g. Calculate the heat loss from the
underground area.
3.
EQUIPMENT/MATERIALS
All HVAC equipment and materials shall be certified to
have been tested and rated for performance and to conform
to all applicable codes and standards listed herein. All
HVAC equipment and materials shall be new and be the
latest products selected from the approved vendors’ list:
This project work has been intended to suggest a suitable
clean room facility and comfort air conditioning design for
the various public areas and rooms of a proposed .Develop a
simplified Archives building HVAC system which could
predict the temperature variation within the building and
estimate the amount of energy required to get the comfort
level using. For the estimation, this model would take into
account of different physical properties of Archives
building, location of Archives building, weather, gains and
heating system. As a case study, the model has been
implemented to a semi-detached dwelling with all the real
data. then compared with another software which is verified
against Archives Building Energy Simulation Test
(Archives) building load and HVAC tests. The main
advantage of this model is its simplicity and less
computational resources
II.
EXPERIMENTAL LAYOUT
The layout shown in Fi gure 1 given below:
I.
Cleanroom Facility
Clean rooms are defined as specially constructed,
environmentally controlled enclosed spaces with respect to
airborne particulates, temperature, humidity, air pressure,
airflow patterns, air motion, vibration, noise, viable (living)
organisms, and lighting. Particulate control includes:
 Particulate and microbial contamination
 Particulate concentration and dispersion
“Federal Standard 209E” defines a clean room as a
room in which the concentration of airborne particles is
controlled to specified limits.
“British Standard 5295” defines a clean room as a
room with control of particulate
contamination,
constructed and used in such a way as to minimize the
introduction, generation and retention of particles inside the
room and in which the temperature, humidity, airflow
patterns, air motion and pressure are controlled.
2.1 Clean Room Classification:
The industry differentiates between the cleanliness
of rooms by referring to class numbers. Federal Standard
209E, “Airborne Particulate Cleanliness Classes in Clean
Rooms and Clean Zones”, September 11, 1992, categorize
clean rooms in six general classes, depending on the particle
count (particles per cubic foot) and size in microns ( m).
The first three classes allow noparticles exceeding 0.5
microns (m), and the last three allowing some particles up to
5.0 microns. Interpreting the table above, a class 100,000
clean room limits the concentration of airborne particles
equal to or greater than 0.5 microns to 1 00,000 particles in
a cubic foot of air.
ISO/TC209 clean room class ratings are
slowly replacing the Federal Standard 209E ratings.
ISO/TC209 is based on metric measurements whereas
Federal Standard 209E that is based on imperial
measurements. The classes, according to ISO/TC209 146441, are in terms of class levels 3, 4, 5…of airborne particulate
cleanliness. A Class 5 means that less than 3,520 particles
(0.5 microns in size) are present per cubic meter, which
equals 100 particles per cubic foot. A Class 6 indicates less
than 35,200 particles per cubic meter. The higher the class
number, the more are the particles present.
Federal
standard 209E
1
10
100
ISO
3
4
5
1000
10000
100000
6
7
8
4.
Room entrances such as air locks and pass-through are
used to maintain pressure differentials and reduce
contaminants.
Air showers are used to remove contaminants from
personnel before entering the clean space.
5.
2.2 Sources Of Contamination: The source of the
contamination is categorized as external sources and
internal sources
A. External Sources - For any given space, there
exists the external influence of gross atmospheric
contamination. External contamination is brought in
primarily through the air conditioning system through
makeup air. Also, external contamination can infiltrate
through building doors, windows, cracks, and wall
penetrations for pipes, cables and ducts. The external
contamination is controlled primarily by
1. High efficiency filtration,
2. Space pressurization and
3. Sealing of space penetrations
B.Internal Sources- The potentially largest source
is from people in the clean room, plus shedding of surfaces,
process equipment and the process itself. People in the
workspace generate particles in the form of skin flakes, lint,
cosmetics, and respiratory emissions. Industry generates
particles from combustion processes, chemical vapors,
soldering fumes, and cleaning agents. Other sources of
internal contamination are generatedthrough the activity in
combustion, chemical, and manufacturing processes. The
size of these particles ranges from 0.001 to several hundred
microns. Particles larger than 5 microns tend to settle
quickly unless air blown. The greatest concern is that the
actual particle deposits on the product. Control is primarily
through airflow design. Although airflow design is critical,
it alone does not guarantee that clean room conditions will
be met. Construction finishes; personnel and garments;
materials and equipments are sources of particulate
contamination that must be controlled. Important control
precautions include:
1. Walls, floors, ceiling tiles, lighting fixtures, doors, and
windows construction materials that must be carefully
selected to meet clean room standards.
2. People must wear garments to minimize the release of
particles into the space. The type of garments depends
on the level of cleanliness required by a process.
Smocks, coveralls, gloves, and head and shoe covers
are clothing accessories commonly used in clean spaces
3. Materials and equipment must be cleaned before
entering the clean room.
2.3. Controlling Cantaminatian With A Clean
Room:
Clean room contamination is controlled by six
major means:
(1) Facility design
(2) Equipment used in the room
(3) Procedures employed
(4) Personnel activity
(5) Environment control
(6) Maintenance
2.4 Panels:
ASTM standards are followed strictly in
the making of our pre-painted, galvanized steel panels.
There is special gasket for air tightness between the frame
and fixed panels. Hot dip galvanized steel is used for
making inner panel for double skin panels. To achieve
uniformity, access doors are made with similar material.
II.
Hvac Facility
HVAC design for health care facilities is all about
providing a safer environment for patients and staff. The
basic difference between air conditioning for healthcare
facility and that of other building types stem from:
1. The need to restrict air movement in and between
the various departments (no cross movement).
2. The specific requirements for ventilation and
filtration to dilute and reduce contamination in the form of
odor, airborne micro organisms and viruses, and hazardous
chemical and radioactive substances. Ventilation
effectiveness is very important to maintain appropriate
indoor air quality.
3. The different temperature and humidity
requirements for various areas and the accurate control of
environmental conditions.
4. The design sophistication to minimize the risk of
transmission of airborne pathogens and preserve a sterile
and healing environment for patients and staff.
These requirements demand very high quantities of
outside air along with significant treatment of this
ventilation air, including cooling, dehumidifying, reheating,
humidifying and filtration.
3.1 Infection Control
In a hospital environment, there tend to be high
concentrations of harmful micro-organisms. From an
infection control perspective, the primary objective of
hospital design is to place the patient at no risk for infection
while hospitalized. The special technical demands include
hygiene, reliability, safety and energy-related issues.
Infections, which may result from activities and
procedures taking place within the facility, are a cause for
great concern. Three main routes responsible for infections
are contact, droplet, and airborne transmission, which are
quite affected by room design and construction factors.
3.2 Contact Transmission
Contact transmission is the most important and
frequent mode of transmission of infections (nosocomial). It
can be subdivided into direct-contact transmission and
indirect-contact transmission.
a) Direct-contact transmission involves direct
body to body contact for the transfer of micro-organisms
from an infected person to a susceptible host.
respectively.
b) Indirect-contact transmission involves the contamination
of an inanimate object (such as instruments or
dressings) by an infected person.
III.
Equations
Load estimation:
SAMPLE CALCULATION:
5.4.1Clean room-1 calculations using wall panel:
Consider Clean room-1 dimensions are (5.45m x 3.35m x
2.4m)
Outside design conditions
Table - 1
Out
side
Room
DBT
0
F
108
WBT
0
F
80
RH
(%)
30.35
W
(gr/lb)
100
Enthalpy
(h)
41.5
73.4
59.54
45
53.41
24.5
Solar gain-Glass
Solar heat gain =
A x R x M.F
Where, A
=
Area of glass in ft2
R
=
Solar gain in BTU / hr
M.F
=
Multiplying factor for
the type of glass, shading, ect
Similarly from the CARRIER Hand Book, the Multiplying
Factor for ordinary glass and inside Venetian blind = 0.56
(table - 16)
1. North glass
Area of the glass
Solar Heat gain
=
=
10.76 ft2
A x R x M.F
=
10.76 x 22.72 x
0.54
=
268 BTU / hr.
Solar and Transmission heat gain – Walls and Roof
Heat gain
=
A x U x EqTD
Where, A
=
Area of the wall or roof
in ft2
U
=
Transmission
coefficient of the wall or roof in BTU//hr/ft2 / 0F (Table - 21)
EqTD
=
Corrected
Equal
temperature difference in 0F
From the CARRIER Hand Book,
The Transmission coefficient of the wall is having 12
thickness and 3/8” gypsum plaster = 0.28 BTUhr/ft2/0F .
EqTD = Equivalent temperature difference + Correction
Factor.
Correction Factor from the CARRIER Hand Book,
At Out side design temperature minus room temperature and
Daily range is = 26.5 0F .
Where, outside design temperature minus room temperature
= 108 – 73.4 = 38 0F.
Daily range = 140F.
1. North wall
Heat gain
=
AxUxEqTD
Where, A
=
Area of the wall
=
width x hight
=
3.35 x 2.4 = 8.04 m2
=
8.04 x 10.76
=
86.51 ft2
U
=
Transmission coefficient of the
wall
=
0.46 BTU/hr/ft2/0F
EqTD
=
Equivalent
temperature
difference + Correction factor (Table - 19)
=
4+20.5
=
24.50F
Heat gain
=
86.51 x 0.46 x 24.5
=
974.97 BTU/hr
Transmission gain except walls and roofs
1. Glasses
Heat gain
=
A x U x T. D
Where, A
=
Area of the total glasses
=
1x1
=
10.76 ft2
U
=
Transmission
Coefficient for glasses from the CARRIER hand Book
(Table - 33)
=
108 – 73.4
=
34.65 0F
Heat gain due to glasses =
10.76 x 0.54 x 34.65
=
201.03 BTU / hr
2. Partitions
A
=
Area of the partition
walls (not exposed to sun)
=
1490.64 BTU / hr
U
=
Transmission
Coefficient for partition walls from the CARRIER hand
Book
=
0.15 BTU / hr
T.D
=
Temperature Difference
between the surroundings and the conditioned space minus
50F
=
108 – 73.4 - 5
=
29.6 0F
Heat gain due to partitions
=
1490.64x 0.15
x 29
=
6618.44 BTU /
hr
3. Ceiling
A
room
=
Area
of
the
=
196 ft2
U
=
Transmission
Coefficient for partition walls from the CARRIER hand
Book
=
0.37 BTU/hr
ft2/oF
T.D
=
Temperature
Difference between the surroundings and the conditioned
space minus 50F
=
108 – 73.4 - 5
=
29.6 0F
Heat gain due to ceiling =
196 x 0.2 x 29.6
=
1160.32 BTU / hr
Internal Heat gain
1. People
Heat gain for people
Where, N
people
=
=
N x Sp
Number
of
=
2
Sp
=
Sensible heat
per person from the CARRIER hand Book
=
245 BTU / hr /
person (Table - 48)
Heat gain from people
=
2 x 245
=
490 BTU / hr
2. Lights
Load due to lights is calculated below
Fluorescent light
=
Total watts x 1.25 x
3.41
Considering 1 watt/sq ft,
A
=
Area of the
room
=
196 ft2
Heat gain due to lights
=
294 x 1.25 x 3.41
=
1249.5 BTU / hr
3. Equipments
Load due to equipment’s =
Equipments load
=
Load due to equipments =
Total watts x 3.41
1 KW
1 x 3.41 x 1000
=
3400 BTU / hr
Sub total of Room sensible Heat
Adding the values of North glass +North wall +Glass
+Partitions +ceiling +people +Light +Equipments is giving
the sub total of room sensible heat.
R.S.H(sub)
=132.01+974.97+201.03+6618.44+1160.32+490+1
249.5+3400
=
14226.21 BTU
/ hr
Safety Factor
An addition of 5 % on sub total of room sensible
heat is taken as a safety factor.
S.F
=
0.05
x
14226.21
=
711.31 BTU/hr
Room Sensible Heat
Adding the value of R.S.H (Sub) +S.F gives the room
sensible heat .
Room sensible Heat
=
14226.21 + 711.31
=
14937.52 BTU / hr
System heat gain
This system heat gain generally take 10% of room sensible
heat.
System gain heat =
0.1 x Room sensible heat
=
0.1 x 14937.52
=
1493.75 BTU/hr
Heat gain through (by passed) fresh air
The room load due to the by passed fresh air (through the
cooling coil) is
Heat gain in BTU/hr
=
Cfm x 1.08 x BF x TD
From the CARRIER handbook, for this type of application
is = 10
Total cfm
=
Number of people x
cfm/person
1545.70𝑋 7
cfm
=
60
=
180.33 BTU/hr
Coil Bypass Factor from CARRIER hand book , for this
type of application is =0.1
Where TD
=
Temperature Difference
between the surroundings and the conditioned space
=
108 – 73.4
=
34.6 0F
Heat gain
=
cfm x 1.08 x B.F x TD
=
180.33 x 1. 08 x 0.06 x
34.6
=
404.31 BTU/hr
Effective Room sensible Heat
It is obtained by adding up the items
Effective Room sensible Heat
=
14937.52+1493.7+404.31
=
16835.58 BTU/hr
Latent heat
1. Occupancy load
Heat gain from people
=
Where, N
=
person from the CARRIER hand book
=
N x Lp
Latent heat per
=
BTU/hr/person (Table - 48)
Heat gain from people
=
=
205
2 x 205
410 BTU /hr
Sub total of room latent heat
Adding the values of latent heat the sub total of room latent
heat is got.
Sub total of latent heat
=
410 BTU //hr
Safety Factor
An addition of 5 % on sub total of room sensible heat is
taken as a safety factor.
S.F
=
0.05 x 410
=
20.5 BTU /hr
Room Latent Heat
Adding the values of
room latent heat + safety factor
=
sub
total
of
=
410+20.5
=
430.5
BTU /hr
Heat gain through (by passed) fresh air
The room load due to the by passed fresh air (through the
cooling coil) is
Heat gain through fresh air
=
cfm x 60 x
0.075 x 1059 x BF
x (w0-wi)/700
=
cfm x BF x
(w0-wi) x 0.68
=
56.91 BTU/hr
From the CRRIER handbook, for this type of application is
= 0.1
Total cfm
=
Number of people x cfm
person
=
627.65 cfm
Coil Bypass Factor from CARRIER hand Book, for this
type of application is = 0.1
From psychrometric chart,
W0
=
Specific humidity at outside
conditions
=
100 gr /lb
Wi
=
Specific humidity at inside conditions
=
53.41 gr /lb
W0 – Wi =
100-53.41
=
46.59 gr /bl
Heat gain
=
180.33 x 0.06 x 0.68 x (114.9256.91)
=
627.656 BTU /hr
Effective Room Latent Heat
It is obtained by adding up the items
Adding the Room latent heat + heat gain + through(by
passed) air
=
430.5 + 627.65
1058.15 BTU /hr
Effective Room Total Heat
It is sum of effective room sensible heat and effective room
latent heat.
Effective Room total Heat
=16835 + 1058.15
=17893.33 BTU /hr
Outdoor air Heat
(1) Sensible heat
Out door air sensible heat =1.08 x cfm x (1-BF) x TD
=
1.08 x180x (1-0.06) x 34.6
=
6334.25 BTU /hr
(2) Latent heat
Out door air Latent heat =
0.68 x cfm x (1-BF) x
(W0-Wi)
=
0.68 x 180.33 x (1-0.06) x (114.95-56.91)
=
6689.63 BTU /hr
Grand total heat
Adding the values of items
Effective Room Total Heat + Sensible heat + Latent heat
Grand total heat
=
1058+6334.25+6689.63
=
14079.03 BTU /hr
=
14079/12000
Load for Marriage hall
=
1.173 TR
Total No. Of Room
=
1
Total Load for Marriage hall
=
1 x 10.64
=
1.173 TR
Determination of Air Quantity (cfm)
The air quantity in
𝐸𝑅𝑆𝐻
Cfm
=
1.08 𝑋 (𝑇𝑟𝑚−𝑇 𝑎𝑑𝑝)(1−𝐵𝐹)
Effective Room Sensible Heat Factor
It is the of Effective Room Sensible Heat to Effective Room
Total Heat
Effective room sensible heat
ERSHF =
Effective room total heat
=
16835.58/17893.93
=
0.940
VI. CONCLUSIONS
Now days many manufacturing process requires
that space to be designed to control particulate and
microbial contamination while maintaining clean room
facility with installation and operating cost. Present days we
are using filters and panels to be addition for constructed
building In this thesis, the system design thermal loads,
filtration level and cleanness, pressures produced in the
constructed building by varying normal brick wall, brick
wall with attached panels are calculated. By observing the
system design thermal loads brick wall with panels is better
than normal wall since its heat transfer rate of normal wall is
more. In this thesis filtration level is better using brick wall
with panels since dust particles form on the wall. In the
design analysis the cooling load tonnage value of brick wall
with panel is 97TR and normal brick wall is 140TR.So the
cooling load and air flow is better by using brick wall with
panel.
1 Future Scope
From this thesis, we have concluded that using filter
materials will be varying number of filters will be reduced
in the room and also air handling unit size will be decrease.
VII. Acknowledgement
The authors thanks C. DAKSHEESWARA REDDY
M.Tech coordinator and Dr. V.S.K.REDDY Principal for
their encouragement during this study.
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