bee - green factors
TRANSCRIPT
GREETINGS
Air Treatment Engineering P Ltd
Energy Efficient designs - 12 Lakhs sft
Normal• 200 Sft / TR
• 6.6 w / Sft
• 6000 TR
• 9000 KW
• 11250 KVA
• Rs 200 / Sft (AC)
• Rs 210 / sft ( Elec)
Energy design• 550 sft / TR
• 2.73 w / sft
• 2200 TR
• 2420 KW
• 2850 KVA
• Rs 150 / Sft (AC)
• Rs 60 / sft
• CCR of 2 crores/Yr
Thermal Comfort
Thermal Comfort
Factors defining thermal comfort are
Metabolic rate
Clothing Insulation
Air Temperature
Radiant Temperature
Air Speed
Humidity
Human Response to Heat
Heat Balance Equation,
S = M – W – E – Q
Where,
S = rate of heat storage of human body, W/m2
M = metabolic rate of human body, W/m2
W = mechanical work produced by human body, W/m2
E = rate of total evaporative loss due to evaporation of sweat, W/m2
Q = total rate of heat loss from skin (dry heat exchange), W/m2
Metabolic Rate
Metabolic Rate depends upon
Degree of Muscular Activities
Environmental Condition and
Body Size
The unit of Metabolic Rate is ‘met’ which is equivalent to 58.2 W/m2
Metabolic Rate of Various Activities
Activity Metabolic Rate(Met)
W/m2
Sleeping 0.8 47
Seated, quiet 1.0 58.2
Standing, relaxed 1.2 70
Walking 2 to 3.8 116 to 221
House Cleaning 2 to 3.6 116 to 210
Washing by hand and ironing
1.2 to 1.4 70 to 81
Office Work 1.1 to 1.3 64 to 76
Drafting 3 to 4 175 to 233
Cont..,
Activity Metabolic Rate(Met)
W/m2
Carpentry 4 to 4.8 233 to 280
Sawing 3 to 3.4 175 to 198
Foundry work 2.2 to 3 128 to 175
Using pneumatic hammer
1.4 to 1.8 82 to 105
Garage work 3.5 to 4.5 204 to 262
Laboratory work 2 116
Machine work 1.6 93
Teacher 3.2 186
Evaporative Heat Loss
Respired Vapour Loss
Latent Respiration Heat Loss
Sensible Respiration Heat Loss
Evaporative Heat Loss from Skin Surface
Evaporative Heat Loss by Skin Diffusion
Heat Loss due to Sweating
Clothing Insulation
Effect of Clothing Insulation
Thermal Insulation of Clothing
Evaporation Resistance of Clothing
‘Clo’ represents clothing thermal resistance value. 1 “clo” = 0.155 m2K/W
‘Clo’ Values for Clothing
Clothing Combination
Clo m2K/W
Naked 0 0
Shorts 0.1 0.018
Typical Tropic Clothing Outfit
0.3 0.047
Light Summer Clothing 0.5 0.078
Working Clothes 0.8 0.124
Typical Indoor Winter Clothing Combination
1 0.155
Heavy Traditional European Business Suit
1.5 0.233
Operative Temperature
Formula to Calculate Operative Temperature
Tmin, Icl = [(Icl – 0.5 clo) Tmin, 1.0 clo+ (1.0 clo – Icl) Tmin, 0.5clo] / 0.5 clo
Tmax, Icl = [(Icl – 0.5 clo) Tmax, 1.0 clo+ (1.0 clo – Icl) Tmax, 0.5clo] / 0.5 clo
where
Tmax, Icl=upper operative temperature limit for clothing insulation Icl, Tmin, Icl=lower operative temperature limit for clothing insulation Icl, Icl=thermal insulation of the clothing in question (clo).
Limits – Clothing insulation 0.5 to 1.0 clo
– Air speed not greater than 40 fpm
– Average metabolic rate 1.0 to 2.0 met
– Humidity ratio should not exceed 0.012
Operating Temperature for Working Clothes (0.8 clo)
Tmin = (0.8 – 0.5) 71 + (1 – 0.8) 78 / 0.5
= (0.3 x 71) + (78 x 0.2) / 0.5
= 21.3 + 15.6 / 0.5
= 73.8 F
Tmax = (0.8 – 0.5) 77 + (1 – 0.8) 83 / 0.5
= (0.3 x 77) + (83 x 0.2) / 0.5
= 23.1 + 16.6 / 0.5
= 79.4 F
Operating Temperature for Working Clothes (1.5 clo)
Tmin = (1.5 – 0.5) 71 + (1 – 1.5) 78 / 0.5
= (1 x 71) - (78 x 0.5) / 0.5
= 71 - 39 / 0.5
= 64 F
Tmax = (1.5 – 0.5) 77 + (1 – 1.5) 83 / 0.5
= (1 x 77) - (83 x 0.5) / 0.5
= 77 – 41.5 / 0.5
= 71 F
Human Comfort Zone Plotted on Psychrometric Chart
PPD Vs PMV
For a PMV range -0.5 <PMV<0.5 – PPD < 10
Air Speed
Air speed is limited to 160 fpmMax temperature shift in operative temp can be 3o C
Bio-Climatic Chart Ogyays
Large Fan with Low Power
Large Fan with Low Power
Radiant Temperature Asymmetry
Radiant Temperature Asymmetry °C (°F)
Warm Ceiling <5 (9)
Cool Wall <10 (18)
Cool Ceiling <14 (25.2)
Cool Wall <23 (41.4)
PPD < 5%
Vertical Air Temperature Difference
Vertical Air Temp Diff is <3o C (5.4 F)PPD < 5%
Draft
Unwanted cooling of the body due to air movement
DR = ([34-ta] * [v-0.05]0.62) * (0.37 * v * Tu + 3.14) ,
where
DR=predicted percentage of people dissatisfied due to draft
ta=local air temperature, °C
v=local mean air speed, m/s
Tu=local turbulence intensity, %.
PPD due to draft < 20%
Allowable air speed as a function of Air Temp and Turbulence Intensity
Drifts and Ramps
Drafts – Refers to passive temperature change
Ramps – actively controlled temperature change
Limits on Temperature Drifts and Ramps
Time Period 0.25 h 0.5 h 1 h 2 h 4 h
Max Operative Temp Change allowed
1.1 (2) 1.7 (3) 2.2 (4) 2.8 (5) 3.3 (6)
Naturally Conditioned Space
Mean monthly outdoor air temperature 10<air temp<33.5o CPPD < 20 to 10%
HVAC
HVAC
• Glass load analysis
• Fresh air management ( 33%)
• Earth Air Tunnel Design
• Slab Cooling
• Indirect Evaporative Cooling
Glass Load Analysis
Design - Glass
Fix the LTC of the glass – required for harvesting
Select multiple glasses with variable U factor and SF
Use the cost data from the respective vendors
Carry out a full study report for the whole year using good soft wares
Sample glass load analysis
Glass Load -Total Building
Glass Type Glass Code GlassCost Equip.cost First Cost Opera+Maintance cost TR
DGU ST 408 1 348.72 38.46 416.10 53.24 149.73
Ref Green 2 140.76 118.38 348.08 163.83 460.72
ST 408 3 225.85 69.78 348.11 96.61 271.69
DGU Green 4 261.42 71.84 387.20 99.40 279.52
green laminate 5 265.57 118.69 473.46 164.28 461.99
DGU skyblue 6 268.13 69.18 389.21 95.68 269.07
ST Blue 7 214.50 104.65 397.77 144.82 407.27
DGU ST blue 8 341.86 55.74 439.42 77.09 216.79
low e 9 288.23 68.86 408.66 95.16 267.68
Ordinary Glass 6mm 10 42.33 167.05 334.61 230.97 649.51
Ordinary Plain Glass-DG 11 148.17 118.28 355.00 163.44 459.62
Deep Blue 12 469.90 32.58 526.92 45.06 126.71
Ultra Marine 13 463.55 45.14 542.51 62.39 175.46
Marine Blue 14 482.60 37.30 547.87 51.57 145.02
SGG Climailit 15 392.33 62.95 502.53 87.09 244.90
Cooling Cost Savings
Product Running Cost
lacs / annum
Ordinary Glass 6mm 532 189
Ordinary Plain Glass-DG 392 266
ST Blue 314 111
Low e 226 80
ST 408 202 72
Turquoise ST 436 151 54
DGU ST 408 113 40
A/C tonnage for cooling heat through glass
NormalChoice
Selected Glass
Investment Cost
Resulting in 13% savings with no additional investment cost
Product Running Cost A/C +Glass
lacs / annum Cost in lac
Ordinary Glass 6mm 532 189 265
Ordinary Plain Glass-DG 392 266 265
ST Blue 314 111 271
Low e 226 80 276
ST 408 202 72 228
Turquoise ST 436 151 54 266
DGU ST 408 113 40 262
A/C tonnage for cooling heat through glass
Investment CostRemains the same
Fresh Air Management
Fresh Air Management
Fresh Air Load
Peripheral Load
Room Load
ADP and compressor power
ADP with out fresh air load = 55
ADP with fresh air load = 51
Savings + 8 to 10%
Fresh Air Load
Fresh Air can be handled using
Special Dedicated Outdoor Air Unit
Active Heat Recovery Machines
Specially designed Treated Fresh Air Units (0.3 to 0.4 Kw/TR)
Dedicated Outdoor Air Systems(DOAS)
Fresh air – Load reduction
Heat recovery wheel
Determine the enthalpy drop required
Estimate the SHF of the fresh air
Select the right HRW wheel
Use an AHU with class B leak
Room exhaust air – from the return air path
Use CO2 sensors
Vary the flow using VFDs on the fans based on CO2 diff
Expected drop in load is around 12 to 15%
Heat Recovery Machine
PRE COOLING THE FRESH AIR
Earth Air Tunnel Cooling
Pre-cooling/Earth Air Tunnel Cooling
Input air is pre-cooled using earth air tunnels
Pre-cooled air is then fed into HRW and then to the specially designed DOA for further cooling
Fresh air through a DOA can be designed to have a low grain content to facilitate moisture control in the room
Supply air could be around 25 deg C.
EAT Cooling
Geothermal Cooling
CFD Analysis of Earth Air Tunnel:
Chilled Beams
Chilled Beams
Chilled Beam
Cooling Panels
Induction Unit
Slab Cooling
Slab Cooling
Slabs at around 20o C
Water piping with pre-cooled water
Air duct as a part of concrete
Air duct connected to pre-cooling / EAT
Slab Cooling
Slab Cooling
Pre-casted Concrete Ducts
Modular Integrated Terminal (MIT)
Modular IntegratedTerminalMIT
Floor Panel
Carpet
DamperActuator
FloorSupport
FlexCoolController
Cast AluminiumGrill
Air InletfromFloor Void
Air Supply to Room
Floor Grille: Arranged in any of 16 flow patternsfor personal comfort
Modular Fan Terminal (MFT) Summer Perimeter Zone cooling
MinimuFreshAir
RoomAir
MITMIT
Fan MFT
Electric orHot WaterHeater
Filter
Plenum Plenum
Glazing
WarmSupply Air
Minimum fresh airfrom floor void
Occupied Space
15.5oC
22.5oC
22.8oC
24.4oC
26oC
27.4oC
Breathing Zonewell mixed
I don’t care region
1.8 m
1.2 m
Polluted Air
Interior Zone Cooling
MIT MITFloor Void Pressure maintained at 7 Pascal
Data Center Design
Data Centre Layout
Under Floor Supply – ASHRAE
Aisle Air Containment
Data Center Design
Conventional way of designing data center claims 50 to 60 sft per ton
Our innovative design claims only 200 to 250 sft per ton
This can be carried out with the help of Indirect Evaporative Cooling and CFD Analysis
CFD Analysis Showing Serer Surface Temperature
Sectional Layout Showing Temperature
CFD Analysis Showing Air Flow Velocity
Indirect Evaporative Cooling Design
Indirect Evaporative Cooling
Indirect Evaporative Cooling
Multi-Stage Indirect Evaporative Cooling
It is very useful in hot & dry climate
Very low power consumption
About 30% savings on installed capacity and 50-60% savings on energy
Multi-Stage Indirect Evaporative Cooling
District Cooling
District Cooling
District Cooling is the centralized production and distribution of chilled water from a central plant to individual buildings through a network of underground pipes
The energy produced can include heating / cooling or electricity
Heating is in the form of steam or high temperature hot water
Cooling is in the form of chilled water
If electricity is co-generated, it is usually used with in the central plant
District Cooling - Benefits
Reduce capital investment cost of cooling system
Lower operational and energy expenses
Conserve space – No need of chillers in individual building
ApplicationSpecial Economic Zones
Townships
IT Parks
Large Campuses
Airport
College Campus
Shopping Malls
District Cooling Schematic
Zero Energy Design
Assumption
2 stories building, 3 lakh sq.ft each, totaling to 6 lakh sq.ft
Occupancy 60 sq.ft/person @ 80% diversity
Computers 150w/computer
Fresh air 20 CFM/person
Building is assumed to be operation between 9 AM to 6 PM for 6 days a week
Load Estimation – Normal Building
Total Load = RL - 1988 + FA – 1022 = 3010 TR
Assuming use of Air cooled chillers,
Power consumption @ 1.5 KW/TR = 270 LKW/Yr
Power cost @ Rs. 6 per KW = 1625 Lakhs
Power cost per sqft per year = 270 Rs
Total Demand per day = 36600 TRH
Power Demand per day = 54900 KWH 1
Solar Power Produced
Install solar panel on 80% of roof area
Solar power that can be produced = 12850 KWH 2
Since power demand per day (1) is more than the power produced by solar PV panel (2), we could not meet the load demand
Strategy Adopted
ECM Adopted Energy Demand
Normal Building 54900 KWH
ECM1 – Select proper glazing 47850 KWH
ECM2 – Building Insulation 42750 KWH
ECM3 – Heat Recovery Wheel 28950 KWH
ECM4 – Earth Air Tunnel 25300 KWH
ECM5 – Demand Control Ventilation 25000 KWH
ECM6 – Water Cooled Chillers 16960 KWH
ECM7 – Indirect Evaporative Cooling 12420 KWH
Actual Power produced with installed solar power 12850 KWH
Normal BuildingNormal Building Innovative DesignInnovative Design
Comparison
Oil free Compressors
Energy efficient
Oil free quiet operation
Extended life with minimal maintenance
Available in small capacities – 60 to 150 TR
Customized VRV
Specially designed VRV machine with oil free compressor as outdoor unit.
Floor mounted AHU acts as indoor unit
Integrated Chilled Water Control System
CONTROL SEQUENCESNatural curve sequencingEqual marginal performance principleDemand Based Control
VFD
VFD
Integrated Chilled Water Control System
Ultra Efficient Integrated Chilled Water Control System
Efficiency is about 0.5 KW/TR
Best for interoperability, Web-based access, automation interface, and remote location control
VFD Vs CSD
De-Super Heater on Chillers
Every building requires hot water
40 to 45o C of hot water can be generated
Solar Powered Chillers
A solar collector array supplies hot water as a source of energy to the absorption cooling machine through hot storage
Electricity is generated by means of solar panels and the same is used to run the chillers
Refrigerator based hot water generator
Very efficient way to generate hot water
Cool air and cold water can be a by product
Can be applied in Hotels, Hospitals, Restaurants etc.,
Hot water generator
AHU’s
Low noise AHU’s
Avoid silencers
Equipments to maintain coil
Ducting
Avoid plenum
Use CFD for air flow study
Reduce pressure drop
Continuous Analysis
Set check points
Input data from sites
Keep analyzing on a weekly basis
Bring in SOP for corrections
VFD’s on Motor
Most motors have VFD
Latest statistical information is very handy - Avoid bye-pass starters
CO2 based Fresh Air
Supply and exhaust fan too have drives
Fresh air supply duct to have VAV’s for each zone
Multiple CO2 sensors in each zone
Avoid Impeller Trimming
Select the pump with full impeller
Run it on low speed with drive
Do not use bye-pass starters
Free Air Cooling AHU’s
Can be used in some parts of the country
Use humidifiers if RH is low
Use exhaust fans
Temperature Set Points
Peripheral heat load to be conducted
Use right glass selection
Vary the set point with respect to ambient
Increased draft using special fans
Serial Chillers
Chilled water from a chiller entering the next chiller for further cooling
Help in improving system COP
Serial Chillers
1 No 500TR chiller with 6 & 13 chilled water in and out – 0.637 IKW/TR
(265 x 1 + 251 x 1) chiller coupled together will give 0.604 and 0.554 IKW/TR respectively
By using serial chillers we can save up to 9% of energy
Cascade System
2.4 GPM/TR - 2500 GPM
1.4 GPM/TR – 730 GPM
Pumping load comes down drastically and there by we can save 70% of energy with out disturbing the efficiency of the system
Low Flow System in Chilled Water Design
Low Flow Condenser Design
Saves pumping power
Better cooling tower performance
Less water losses
Information
Low delta T SyndromeOver sized coil & control valve
Active load in the building is less
Control valve throttles and reduces flow
On minimum part load coil flow velocity falls below Reynolds no
Flow becomes laminar
Loss of conductivity and hence room not cooled
Control valve opens again to maintain temperature in room
Increased flow and low load on the coil results in reduction of DT
Return water temperature falls down
Chiller identifies – no load and starts part loading
Pump continues to o over work and increase flow , further damaging the situation
IKW / TR & KW/Sft goes up
Remote Monitoring
Schematic Arrangement
Performance contracting
Esco will implement the corrections
Investment of Correction will be by Esco
Savings will be shared between Esco : Client by 80:20 ratio for the first five years and by 70:30 for the next five years
Assurance of a max operating cost on defined conditions
Computational Fluid dynamics
• Wind tunnel study
• Piping designs
• Air moving equipments design
• Air distribution designs
• Reduce power consumption
Statistics as a Design Tool
Most important
Mining of data of clients
Statistical tools to be used for analysis
Live Spread Computation-Chennai
Project Costing
Use
Cost / Sq.ft
Sq.ft / TR
Watts / Sq.ft
Water Quality
Complex Science
Not possible to manually maintain
Use good automated equipments
ATE
Thank you
Management & Staff
Air Treatment Engineering P Ltd
INDIA