Optimum insulation thickness for building envelope a review
Green Energy Final Project
1. 1
Green Building Design Project
Frederick Avyasa Smith & Ayotunde Adenaike
MECE E4314: Energy Dynamics of Green Buildings
Prof. Mohammad H. Naraghi
May 11th
, 2015
2. 2
Table of Contents
Introduction.................................................................................................................................3
Floor Plan......................................................................................................................................3
Floor Planof Theoretical House................................................................................................................................3
Floor Planof Theoretical House IncludingDimensions..............................................................................4
Orientationof Theoretical House.............................................................................................................................4
Construction.................................................................................................................................5
General Design Parameters ofTheoretical House.........................................................................................5
Construction Materials...................................................................................................................................................6
Detailed Elementsof All Windows and Doors...................................................................................................7
Infiltration Calculation...................................................................................................................................................7
Ventilation....................................................................................................................................8
View 1 ofTheoretical House........................................................................................................................................9
View 2 ofTheoretical House.....................................................................................................................................10
View 3 ofTheoretical House.....................................................................................................................................11
View 4 ofTheoretical House.....................................................................................................................................12
Appliances....................................................................................................................................12
Description of Appliances..........................................................................................................................................12
Photovoltaic System .................................................................................................................13
General Information of PV System........................................................................................................................13
Detailed Information of PV System......................................................................................................................13
U-Factors.....................................................................................................................................13
Cooling and Heating LoadValues..........................................................................................................................14
Heat Pump Specifications...........................................................................................................................................14
HVAC System Layout.................................................................................................................15
Overall Layoutof HVAC System..............................................................................................................................15
Heat Pump, Air Handler Unit, and HRV Unit Layout...................................................................................16
Supply Air Ductwork Layout....................................................................................................................................17
Return Air Ductwork Layout....................................................................................................................................18
Exhaust Return Air Ductwork Layout.................................................................................................................19
Conclusion ..................................................................................................................................20
Energy Consumption Per Year................................................................................................................................20
Breakdown ofEnergy Consumption Per Year................................................................................................20
Building Energy Performance Standards.........................................................................................................21
References ..................................................................................................................................22
3. 3
Introduction
The purpose of this project is to design and analyze a small one-family house within ASHRAE
Standards 55 to effectively accommodate pleasant indoor living conditions and reduce the energy
consumption to a minimum. It is noted that this is a preliminary analysis, which includes
justified assumptions. Throughout this analysis, software was utilized to help aid in the
determination of numerous values. This design tool, called Home Energy Efficient Design
(HEED), was created by the Department of Architecture at the University of California, Los
Angeles. The lowest indoor design comfort temperature was set to be 68°F. The highest indoor
design comfort temperature was set to be 75°F.
Floor Plan
For this project, the location of the house to be designed and analyzed is in Islip Long Island,
New York. The house was designed to accommodate four people and it consists of three
bedrooms, one kitchen, one living room, and one and a half bathrooms. The house orientation is
placed towards the south in order to achieve maximum solar gain. Thus, the side of the roof with
the maximum area is also placed due south to accommodate the maximum amount of solar
panels. The layout and orientation of the house can be found below:
Floor Plan of Theoretical House
Figure 1: Floor Plan
4. 4
Floor Plan of Theoretical House Including Dimensions
Figure 2: Floor Plan Showing Dimensions
Orientation of Theoretical House
Figure 3 Orientation of The House
5. 5
Construction
General construction design elements can be found in the table below:
General Design Parameters of Theoretical House
Table 1: Construciton Dimensions
When determining the construction of the roof, walls, and floor a case study was referenced in
which the challenges of creating a residential net zero energy home was explored. A table
detailing the house’s construction can be found below:
6. 6
Construction Materials
Component Description U Factor (BTU/h ft2°F)
Roof Asphalt roof shingles, fully
adhered roof membrane,
overall roof sheathing, ⅝”
plywood roof sheathing with
h-clips, attach to roof framing
using galvanized wood
screws, 1 ½” foil-faced
polyisocyanurate sheathing,
2” foil-faced polyisocyanurate
sheathing, 1 ½” foil-faced
polyisocyanurate sheathing,
continuous fully-adhered air
barrier membrane, ½”
plywood sheathing with h-
clips, 11 ⅞” lsl roof rafter
with cellulose cavity
insulation, ½” gwb seams
taped, painted with latex
paint.
0.014 [2]
Exterior Walls Fiber cement siding, ¾” wd
furring strip, 2 layers 2” foil-
faced polyisocyanurate rigid
insulation, joints staggered
horizontally and vertically,
outer layer sealed with tape,
continuous fully-adhered air
barrier membrane, ½”
plywood sheathing, 2x6 24”
o.c. wood stud wall with
cellulose cavity insulation, ½”
gwd painted with latex paint.
0.022 [2]
Windows Clear triple-pane ¼ inch glass
with insulated krypton gas.
SHGC=0.27[12]
0.242(5’x 5’)
0.256(3’x 4’)
0.261(3’x 3’)
Floor 4” on-grade concrete slab with
w1.4 x w1.4 welded wire
mesh placed at mid-depth,
embedded hydronic tubing, 6
mil polyethylene vapor
0.313 [2]
7. 7
barrier, 2” xps rigid foam slab
insulation, 4” gravel pad, filter
fabric, undisturbed native soil.
Door Insulated steel slab with wood
edge in wood frame.
0.16 [12]
Table 2: Construction Materials and U-Values
Detailed elements of the windows and door can be found below:
Detailed Elements of All Windows and Doors
In order to maximize energy saving capabilities an extremely tight air sealed envelope was
assumed. In reality this requires stringent construction procedures.
Infiltration Calculation
Infiltration in Winter Tight construction house with
no leakage; No obstructions
or local shielding
89.61 CFM
Infiltration in Summer Tight construction house with
no leakage; No obstructions
or local shielding
43,89 CFM
Table 4: Infiltration in the Summer and Winter
Table 3: Dimensions of Windows and Doors
8. 8
In calculating the infiltration, the following equation was used:
Where AL = AesAul
Aul = 0.01 in2/ft2 in a tight construction supervised by an air sealing specialist
Aes = 4779 ft2 (area of the exposed building)
ΔTsummer = 11.6 F
ΔTwinter = 55.9 F
Cs = 0.0150 CFM2/ (in4 F)
Cw = 0.0119 CFM2/ (in4 mph) – building located in an area without obstructions
Vw = 15mph in winter and 7.5 in summer
From table 4 above, it can be noted that the infiltration during the summer (43.89 CFM) is less
than the infiltration during the winter (89.61 CFM).
Ventilation
Using ASHRAE 62.2 the ventilation requirements for the entire building can be calculated:
𝑄 𝑓𝑎𝑛 = 0.01 × 𝐴 𝑓𝑙 𝑜 𝑜𝑟 + 7.5 × ( 𝑁 𝑏𝑒𝑑𝑟𝑜𝑜𝑚𝑠 + 1)
56.91( 𝑐𝑓𝑚) = 0.01 × 2691 + 7.5 × (3 + 1)
It is noted that ASHRAE 62.2 requires additional airflow to meet local ventilation requirements.
These local ventilation requirements are necessary for kitchens and bathrooms. In this basic
analysis these local ventilation requirements will be omitted due to the capabilities of HEED.
Continuous fan-forced fresh air ventilation was chosen to meet ASHRAE standards for the
house. In addition to this a Heat Recovery Ventilator (HRV) system was incorporated into the
ventilation system in order to reach maximum energy efficiencies. A 95% efficient HRV system
was chosen for this application. Specification of the HRV unit can be found in the table:
General Information of HRV Unit
HRV Unit Airflow Capacity (cfm) Efficiency (%)
Zehnder Novus 300 177 95
Table 5: Heat Recovery Ventilation
Below one can find several images of the house with different orientations:
9. 9
View 1 of Theoretical House
Figure 4: Front View of the House (South)
10. 10
View 2 of Theoretical House
Figure 5: Side View (West)
11. 11
View 3 of Theoretical House
Figure 6: Rear View (North)
12. 12
View 4 of Theoretical House
Figure 7: Side View (East)
Appliances
Description of Appliances
Appliance Power Rating
(V)
Efficiency Usage Load Factor
GE Profile
Series 27.7 cu.
ft. French Door-
Refrigerator
120 Meets Energy
Star Efficiencies
Continuous n/a
Samsung Chef
Collection 30 in.
5.8 cu. ft. Range
220-240 n/a 3 days per week
(2 hour period)
n/a
13. 13
Samsung 5.6 cu.
ft. Front Load
Washer
120 Meets Energy
Star Efficiencies
6 loads per week n/a
Samsung 7.4 cu.
ft. Electric Front
Load Dryer
220-240 Meets Energy
Star Efficiencies
6 loads per week n/a
Table 6: Energy Star Appliances
Photovoltaic System
The photovoltaic (PV) system’s layout can clearly be observed in Figures 3,4 & 5. The PV
system consists of 37 solar panels. It is noted that an inverter was not specified due to the
limitation of HEED. HEED assumes an ideal inverter in which all electricity is converted via the
inverter. Specification of the Solar Panels can be found in the tables below:
General Information of PV System
Solar Panel Unit Voltage of Solar Panel (V) Output of PV System
kWh/year
Sharp ND-240QCJ 240 11930.94
Table 7: PV System
Detailed Information of PV System
Table 8: PV System Specifications
U-Factors
As mentioned previously the lowest indoor design comfort temperature was set to be 68°F. The
highest indoor design comfort temperature was set to be 75°F. The ground reflectance was
assumed to be 0.2 year round. All ductwork for the heating/cooling system was placed inside the
building envelope in order to limit losses to the outside environment. In addition, ductwork was
insulated with cellulose in order to keep heated/cooled air at desired comfort conditions until
reaching appropriate zones. Heating/cooling process is controlled by a smart thermostat, which
enables energy savings by applying conditioned air during specific appropriate times.
Furthermore, natural cooling can be enabled by manually opening windows and doors when
14. 14
outside air is below the designed indoor comfort high temperature. By considering all these
factors heating and cooling loads were generated:
Cooling and Heating Load Values
Table 9: Heating and Cooling Loads
From Table 9 above, the heating system size for the house (-13,894Btu/hr) is stated. This shows
the amount of heat required to keep the house comfortable on its coldest night with no internal
loads. It is calculated from steady state heat flow through the entire building envelope
components plus the makeup air required for what is lost through infiltration and ventilation.
Furthermore, it was assumed that the outdoor air temperature was at its winter design low and
the indoor air was at its indoor comfort low.
On the other hand, the cooling system size (10,437 Btu/hr) is found by simulating the
performance of the building as designed for every hour of the year, then finding the maximum
cooling system demand when the outdoor air temperature is at its summer design high.
With the heating/cooling loads determined an appropriate heating/cooling device could be
selected. A heat pump was chosen to handle heating/cooling loads in the house because of its
extremely high capability for efficiency. Details of the chosen heat pump can be found below:
Heat Pump Specifications
Heat Pump SEER HSPF Cooling Capacity
(BTU/hr)
Trane XL20i 19.00 9.00 24,000.00
Table 10: Heat Pump Specifications
15. 15
HVAC System Layout
The HVAC system was designed to incorporate two high efficiency technologies, a heat pump
and an HRV unit. It is noted that all ductwork is attached to the ceiling. All ductwork is attached
to the ceiling for practicability and efficiency purposes. Ductwork cannot be run under the floor
because of the concrete slab. All return vents are placed at floor level with corresponding
ductwork that attaches to ceiling ductwork. Air supply diffusers are located at ceiling level.
layout of these systems can be found in the figures below:
Overall Layout of HVAC System
Figure 8: Ductwork Layout of HVAC System
16. 16
Heat Pump, Air Handler Unit, and HRV Unit Layout
Figure 9: Heat Pump, Air Handler and HRV Unit Ductwork Layout
20. 20
Conclusion
Ultimately, a beyond net zero house was successfully modeled. The house produced 3,239
kWh/year of electricity while additionally meeting all of the homes required energy needs. The
overall results can be found in Figure 13. It is noted that the first and second bars on Figures 13
and 14 represent early house designs. The third bar represents the most current home design.
Energy Consumption Per Year
Figure 13: Energy Consumption Per Year (Third Bar Represents Designed House)
Breakdown of Energy Consumption Per Year
Figure 14: Breakdown of Energy Consumption Per Year (Third Bar Represents Designed House)
21. 21
Building Energy Performance Standards
Table 11: Energy Performance Standards of Designed House
Attached one can find an excel spreadsheet which contains all energy performance data of the
designed house. This excel file is named “Performance Data”.
22. 22
References
1) Milne, Murray. "HEED: Home Energy Efficient Design." HEED: Home Energy Efficient
Design. Accessed May 11, 2015. http://www.energy-design-tools.aud.ucla.edu/heed/.
2) Pettit, Betsty, and Cathy Gates. "Design Challenges of the NIST Net Zero Energy Residential
Test Facility." Building Science. 2014. Accessed May 11, 2015.
http://www.buildingscience.com/documents/reports/rr-1401-design-challenges-nist-net-zero-
energy-residential-test-facility.
3) Hoellwarth, Craig. "Indoor Ventilation Minimum Best Practices Guide." California Energy
Commission. 2008. Accessed May 11, 2015. http://www.energy.ca.gov/2010publications/CEC-
400-2010-006/CEC-400-2010-006.PDF.
4) "Retrofit Measures for." NREL: National Residential Efficiency Measures Database -.
Accessed May 11, 2015. http://www.nrel.gov/ap/retrofits/measures.cfm?gId=12&ctId=216.
5) "SUNNY BOY 240 US." SUNNY BOY 240-US. Accessed May 11, 2015. http://www.sma-
america.com/products/solarinverters/sunny-boy-240-us.html.
6) "Heat and Energy Recovery Ventilation Units (HRVs, ERVs) | Zehnder." Heat and Energy
Recovery Ventilation Units (HRVs, ERVs) | Zehnder. Accessed May 11, 2015.
http://zehnderamerica.com/products/heat-and-energy-recovery-ventilation-units/.
7) "XL20i." Trane-Residential. Accessed May 11, 2015.
http://www.trane.com/residential/en/products/heating-and-cooling/heat-pumps/xl20i.html.
8) "WF9100 5.6 Cu. Ft. Front Load Washer with SuperSpeed (Onyx)." Samsung Electronics
America. Accessed May 11, 2015. http://www.samsung.com/us/appliances/washers-
dryers/WF56H9100AG/A2.
9) "DV7770 7.4 Cu. Ft. Large Capacity (Electric) Front Load Dryer with Vent Sensor (Stainless
Platinum)." Samsung Electronics America. Accessed May 11, 2015.
http://www.samsung.com/us/appliances/washers-dryers/DV48J7770EP/A2.
10) "Samsung Chef Collection 30 In. 5.8 Cu. Ft. Slide-In Flex Duo Electric Induction Range
with Convection Oven in Stainless Steel-NE58H9970WS - The Home Depot." The Home Depot.
Accessed May 11, 2015. http://www.homedepot.com/p/Samsung-Chef-Collection-30-in-5-8-cu-
ft-Slide-In-Flex-Duo-Electric-Induction-Range-with-Convection-Oven-in-Stainless-Steel-
NE58H9970WS/205469130?N=5yc1vZc3ob#specifications.
11) "GE PROFILE™ SERIES ENERGY STAR® 27.7 CU. FT. FRENCH-DOOR
REFRIGERATOR PFE28RSHSS." GE Appliances. Accessed May 11, 2015.
http://products.geappliances.com/ApplProducts/Dispatcher?REQUEST=SpecPage&Sku=PFE28
RSHSS.
12) Naraghi, Mohammad. Energy Dynamics of Green Buildings. Hoboken, New Jersey: John
Wiley & Sons, 2015.
