Retrofitting for Energy Efficiency by Nikita Sahuji

Energy Efficiency Design Portfolio Guided By Prof. Medha Naik Prof. Sheetal Badge

Submitted By Rutuja Jadhav (609201) Nikita Sahuji (609204)

M.Arch (Environment)

Project Brief: The objective is to understand the application of energy efficiency strategies to be implemented from designing to retrofitting.  Understand energy management of buildings as per the activities in buildings so as to reduce the energy consumption through climate responsive strategies.  Calculations and quantitative supplementing of all strategies at different levels i.e. a) Built elements level (façade, openings, materials) - Planning stage b) Energy management level – operational stage c) Technology level - operations and maintenance stage. 

Criteria to select the Building:

Selecting Institutional Building:

Retrofitting of a medium-scale commercial project in detail or Design of medium scale building project in lieu of energy efficient building design. Ex Commercial complex, Hotels, Hospitals, etc.

  

As collective attempt, all categories of buildings were covered. Institutional building was chosen because it has multiple sub blocks used in different ways, i.e. office and admin, students, visitors, etc. It covers varied user and timestamp throughout the year.

MGM University Building: Scale of building ≥ 0.25 acres

Case study 1 : Packard Foundation Headquarters, California

Any type of air conditioner installed

Access for physical study of building

It was selected to study as it gives scope to study latest HVAC systems as well has scope for passive techniques to reduce energy consumption. It also fulfilled other criteria.

Case study 2 : Aranya Bhavan, New Delhi

HVAC Water cooled chillers STP plant capacity 15m3/d Solar Panels 45 KWP Grid Annual production – 60,000 KWH Lighting Power density ~6w/m2 LED’s and T5 were used

Building Envelope Roof – u value = 0.6w/m2k 40mm polyurethane foam Light colour terrazzo Wall – u value = 0.5 w/m2k 50mm extruded polystyrene Double Glazing – u value = 1.8w/m2k SHGC = 0.24 VLT = 36% 6mm glass with 12mm air gap

Energy Monitoring Cooling System – size reduce 230TR to 165 TR 28% reduction EPI - EPI reduce 77 kwh/m2 to 53 kwh/m2

Source: EHDD Architecture

About the Building: MGM Campus, N-6,CIDCO., Aurangabad, Maharashtra. 431003. JNEC

Latitude: 19.8799 Longitude: 75.3557 Campus area : 2acres University building : 6150sq.ft

Entrance

University Campus Overview

Campus boundary

Climate Study: Temperature (in deg.) Monthly Mean Max Monthly Mean Min Humidity (in %) Average Rainfall (in mm) Average Wind Direction Prevailing winds Secondary Winds

Building Form: J

36.5

31.5

14.5

19.7

24.5

21.5

18.5

160

200

172

148

WNW

NEN WNW

WNW

NNW NNW NW



Highest temperature is 40°C and Lowest is 13°C. Thus Average Meant Temperature (AMT) is 26.5°C.



Maximum Relative Humidity is 72% and Average Humidity is 38%.



Rainfall in monsoons is extremely high i.e. 200 mm.



Majorly prevailing direction is West.

wind

Source: Climate Consultant Software

Harsh sun

Low Humidity

Glare

Low Rains

Hot and Dry Climate Zone Minimise Heat gain

Maximise Natural Ventilation

Cooling towers and Stack Ventilation Design of Openings and shading devices Use of Vegetation and water bodies Materials and thermal insulation Building orientation and form Source: Weatherspark.com



     

Solid-Void ratio of the surrounding

It is a individual building in campus which consist of two parts. 1. University Functioning (Const. completed), 2. School of design ( Const. Ongoing) It is G+3 with one basement. It consists of various administration sections like finance, exam control, PRO, etc. along with the offices all authorities like Registrar, Vice Chancellor, Dean, etc. Basements will be having the student welfare cell, anti ragging cell, etc. It has floor plate of 6150sq.ft and total built up area is 30750sq.ft, out of which only 3 floors are in use i.e. Ground floor, First floor and Third floor. Total area under study = 30750 sq.ft The building character stands out due to exposed brickwork with raw concrete finish combined together.

University Building

Orientation Analysis:

Building Drawings:

North East side  Low sun angles  No chajjas are provided

SWIMMING POOL

WEST

STADIUM

 

South East side Lobby and waiting areas on south Side (Not under Air conditioned area) Horizontal Shading devices can be provide to avoid high sun angles

SOUTH  

South West side Direct Solar Heat Gain Overhangs are provided

Air-conditioned Area = 3132sq.ft (50%)

Shadows of buildings around

15th May, 1.00pm



No building around the University building dominates by height.



Thus no adverse effect on daylight due to shadows of adjacent buildings.



Major landscaping is of vertical growing trees and only few trees with foliage are planted on south east side which are casting shadow on façade.

15th May, 4.00pm



15th Dec, 9.00am

15th Dec, 1.00pm

Shadow of landscape is actually required on south west façade to create buffer to harsh sun

Second Floor

15th May, 9.00am

Air-conditioned Area = 5634 sq.ft (91%)

Ground and First Floor

JAN-MAY WINDS

North West side  Large openings to allow diffuse light and cool breeze from the pool. (In dry period it will help to increase humidity)

EAST

Basement Floor

NORTH

Air-conditioned Area = 5139 sq.ft (84.54%)

15th Dec, 4.00pm

Third Floor

Landscape around the building

Air-conditioned Area = 5420sq.ft (88%)

Energy Audit Sr.no

Daylight Analysis:

Space name

Ground Floor 1 Lobby Area and Corridor areas

Quantity

Unit consumption ( in Watts)

Ceiling fan Ceiling down lights LED spot lights Led Panel Lights 1 Smoke alarms Speakers Computer LED screen 52"

4 19 1 38 5 2 1 1

80 20 9 12 0.4 6 300 100

6 2 2 8 0.1 0.25 6 2

1920 760 18 3648 0.2 3 1800 200

57600 22800 540 109440 6 90 54000 6000

Ceiling fan Ceiling down lights Led Panel Lights 2 Smoke alarms Computer Printer

4 9 21 3 5 1

80 20 15 0.4 300 50

6 2 6 0.1 6 1

1920 360 1890 0.12 9000 50

57600 10800 56700 3.6 270000 1500

Ceiling fan Ceiling down lights Led Pannel Lights 2 Smoke alarms Computer Printer

4 9 21 3 5 1

80 20 15 0.4 300 50

6 2 6 0.1 6 1

1920 360 1890 0.12 9000 50

57600 10800 56700 3.6 270000 1500

Tubelights - 2ft Tubelights - 4ft Exhaust fans

8 4 4

10 20 60

4 6 4

320 480 960

9600 14400 28800

Appliances

Working area (A)

Operational Hours

Consumption per Day

Consumption per month

Working area (B)

Toilets

Working area (c)

Ceiling fan Ceiling down lights Led Pannel Lights 2 Smoke alarms Computer Printer

3 12 16 3 4 1

80 20 15 0.4 300 50

6 2 6 0.1 6 1

1440 480 1440 0.12 7200 50

43200 14400 43200 3.6 216000 1500

Conference Room

Ceiling fan Ceiling down lights Led Pannel Lights 2 Smoke alarms Led Screen 60"

3 12 16 3 1

80 20 15 0.4 100

4 2 2 0.1 4

960 480 480 0.12 400

28800 14400 14400 3.6 12000

Total consumption in Kilowatts

Consumption/month (KWh)



Ground Floor

1084



First Floor

1056



Second Floor

1055

Third Floor

1018

Basement Floor

956

Total

5169

Floor plate

  

Ground Floor Plan

Second Floor Plan    

First Floor Plan

Third Floor Plan

As seen in the above simulation, there is scarce light from the north east side. Also the corridor in centre is in totally dark and needs artificial lighting since 9am. Thus, there is not point in reducing the WWR and there is no scope of increasing also. Thus, while redesigning the windows and its projections, light shelves are to considered, which would help to bring in more light.

1084

A detailed energy audit was done of all the floors as shown above. The above table includes the illumination load and the plug loads. It was recorded manually. Apart from this, the HVAC i.e. cooling load was taken from design builder simulations. Basement floor and second floor are unoccupied but designed and executed, thus they are considered to function in full capacity. Annual plug load = 62352 KWh After adding the cooling load, according to design builder the total annual consumption of the building currently = 71276 KWh

Basement section    

Basement seems to be naturally lit but still the illuminance level is not sufficient for its purpose i.e. office work. But the basement has open planning with no cubicles. Thus it is comparatively much more lit. Certain active techniques can help to fullfill the daylight requirement in the basement. For example, sun shelves could be installed and the surfaces could be cladded with reflective materials.

Existing HVAC System:  

Purpose and Measures:

System used : Daikin’s VRV system (variable refrigerant volume), called as VRF in general In this system, there is one integrated outdoor unit connected to multiple indoors.     50 Hp circuit

30 Hp circuit

Purpose

Physical Measures

Decrease exposed surface area

In order to save the ducting cost and cut down the possibility of air leakage, minimum ducting is used. Thus two outdoors of different capacity i.e. 50 hp and 30hp. Maximum 60hp outdoor can be installed. Use of Two Way horizontal and 4 way swing indoor unit to ensure equal distribution of air.

Trees, shading devices

Increase thermal resistance (R value) Building envelope (wall and roof assemblies)

4- way AC Vent

Source: Daikin Brochure

Increase thermal capacity (Time lag)

Wall and Roof Assemblies

Increase buffer Space

Lobbies, verandas, trees

Increase shading

Overhangs, Tress and Fins

Increase surface reflectivity

Reflective material

Reduce Solar heat gain

Glazing with lower SHGC

With all the above approaches we can reduce the cooling load, the illuminance load and plug loads can be reduced by using smart and efficient equipment. Thus the total energy consumption can be decreased and the efficiency can be increased with these measures.

Solutions: Scenario 1 : With Similar HVAC Volumes Building Components

Roof

Walls

Parameter

R-Value SHGC VLT Energy Consumption

Finding alternative wall, roof and window assemblies and their materials

Option 2

Option 3

Base case

Option 1

Option 2

Option 3

Base case

Option 1

Option 2

Option 3

230 mm exposed brick wall with cement grouting on inner and outside

230mm brick wall with 12mm Lime plaster on inside exposed outside

230mm brick wall with 150mm cavity filled with insulation

230 mm ACB wall cement plaster 24mm outer and 12mm inner

150 mm exposed RCC slab

Green Roof

RCC Slab with terracott a tile outside and gypsum plaster inside

RCC slab with protectiv e roof membran e assembly

4mm clear glass

Tinted glass

Double glazing Air gap 13mm

Triple glazing Air gap 13mm

U value (w/m2k)

2.25

2.1

0.20

0.75

4.82

0.32

0.187

0.32

5.89

5.7

2.66

1.19

R value (m2k/w)

0.44

0.45

4.6

1.32

0.20

3.09

5.3

3.06

0.86

0.46

0.49

0.19

0.89

0.25

0.50

0.22

Assembly type

SHGC

Goals set by ECBC, 2017 Parameter

Wall

Roof

Glass

U-value (w/m2k)

0.44

0.40

3.00

R- value (m2k/w)

2.10

SHGC with WWR40%

0.25

VLT (%)

0.27

GLASS

Option 1

Parameters

R-Value U-Value Energy Consumption Cooling Load

ROOF

Base case

Glass

Parameters

WALL

VLT

Total energy (kwh)

255608

255594

254304

252547

255608

249773.00

254933.5

250015.46

255608

251586.61

254969.4

249655.66

Cooling load (kwh)

71276

71268

69634

68022

71276

65760.66

70340.93

66053.91

Imagery Note: All the above simulation are carried out in design builder software with no landscape around. We believe even the landscape would cause a significant change

Base case and Proposed case Simulation:

South West Landscape buffer:

Base case : 230 mm Exposed Brick walls and 150mm RCC Slab with 4mm clear glass windows Proposed Case : 230mm brick wall with 150mm cavity filled with insulation, Green Roof and Triple Glazed Window Base Case

 Beside mentioned are some of the native trees which have a considerable height and foliage and are capable of casting shadows all over the year.

Proposed Case

300000 255608.6 250000

Sirish

Karanj

243879.25

(Pongame oiltree)

South West Facade

200000

(Albizia lebbeck)

150000 100000

 Use of native trees also do more carbon sequestration and help in reducing the temperature of the surrounding.

-16% 71276.58

Shrubs to be replaced with shading trees

59927.41

50000

Arjuna

(Terminalia arjuna)

0 Cooling Load

 This trees work as a buffer for south west facades and help in cooling down and purify the air before entering into the space.

Putranjiva

(Putranjiva roxburghii)

Total site energy

Solutions: Scenario 2 : Reducing HVAC Volumes Strategies Changing wall, roof and window assemblies Creating landscape buffers Changing fenestration and window sizes

Naturally ventilating spaces: 

Workstations are currently having glass partition till ceiling and are air conditioned.



The space is used 20 people/floor.



According to our study, if we make these partitions of 7ft height and make the space naturally ventilated and remove the hvac, the cooling load can be reduced.

Considerations for Fenestration design   

No shades required Larger openings on other façade with fixed glass 3-level openings for workstations EAST

NORTH

 

Less openings Vertical shading

Increasing overhangs wherever required  

Making open floor plan to facilitate cross ventilation.

Maximum openings Minimal chajjas

WEST

SOUTH    

High Sun angles 3- level openings Horizontal shading Dense landscape

South-West Fenestration Design 

V1 Fixed

Air-conditioned Area

Base case

Air-conditioned Area

Proposed case

W1 Sliding

2ft projection is insufficient

Jali

Wind flow only from W1

W1 Sliding

50 % opening and low WWR

Base case

Exit for warm air in from the room 3ft of projection sufficient

Wind flow only from W1 with 50% opening and higher WWR

Proposed Case



Along with the change in WWR, the opening can be also changed into 3 level opening, i.e. brick jali on top and bottom and sliding window from sill to lintel level with longer projection to cut sun angles. This will allow more flow if air, the hot air will vent out as well.

Shifting to Renewable Energy

Current Energy Expenses

Expenses after Retrofitting

Below calculations are done from Solar Rooftop Calculator by MNRE, with input of following values: Roof Area = 6150sq.ft out of which 60% is available for solar system installation.

Initial energy consumption = 71276 KWh

Energy consumption = 59927 KWh

With Rs. 8/KWh, Annual bill = Rs. 570200

With Rs. 8/KWh, Annual bill = Rs. 479416

16% Reduction in expenses = Rs.90784 saved annually

Solar Rooftop Calculations:

Annual energy requirement = 59927 KWh (excluding HVAC)

Cost of Retrofitting: Area

Unit cost

Total cost

Roof

4214 sq.ft

180 Rs/sq.ft

7,58,520 Rs

Wall

10,051 sq.ft

200 Rs/sq.ft

20,10,200 Rs

Window

3612 sq.ft

420 Rs/sq ft

Excess Energy produced = 8623KWh

Total Solar energy produced = 68550KWh

15,17,040 Rs

Total cost 42,85,760 Rs

= Rs.68984 Deducted annually from MSEB bill (MSEB electricity used for hvac)

Payback Period:  Total cost of solar power plant = Rs. 1747385  Total Cost of Retrofitting = Rs. 4285760  Total amount to be recovered = Rs. 6033145

Total monetary benefit per year = (90784*8)+ (68550*8) = Rs. 1274672/year Thus to recover Rs. 6033145 , it will take around 4.73 Years

Approach to calculations:

Source: Kenbrooksolar

Savings at consumption level i.e. reduction in consumption.

Monetizing the excess solar energy generated

Regular bill turns to be zero due to solar.