Comparative study between Retscreen, DEAP and SBEM software on Study House.

1. Certificate in Environmental & Energy Engineering
Sustainable Energy Systems Modelling
Cork Institute of Technology, Bishopstown, Cork, Ireland
INTR8018-2011-May
DESIGN STUDY ON THE IMPROVEMENT OF ENERGY
EFFICIENCY AT “CLOONBEG”, CASTLEFEKE,
CLONAKILTY, CO CORK.
MAY 2011
Group Members; Paul Butler RY5212240
John McCarthy R00078838
Colm O Mathuna RY2030161

2. Abstract
The study undertaken concerned the energy efficient use of the dwelling house “Cloonbeg”,
Castlefreke, Clonakilty, Co. Cork. The premises was constructed 1990 circa in accordance with the
building regulation governing construction techniques of its era. The premises is a 2 story dwelling
house with a two storey extension constructed 2000 circa. The premises is located on a sheltered site
from wind and is situated approximately 50m east of a stream with the front of the premises facing in
a southerly direction.
It was proposed to access the energy efficiency of the dwelling house taking its current energy
efficiency as its base case. The proposed case undertaken was the assessment of the enhanced
case energy efficiency of the dwelling house using three separate software modelling packages.
The three modelling packages utilised include:
1. RETscreen
2. Dwelling Energy Assessment Procedure (DEAP)
3. Simplified Building Energy Modelling (SBEM)
The proposed case consisted of upgrading the heat loss elements and envelopes of the dwelling
home. This included increasing the insulation in the attic space and providing external insulation to all
heat loss external walls. It also included providing energy efficient lighting and upgrading the boiler
and heating controls while providing solar panels to contribute towards hot water demands.
Using these software modelling packages it was possible to establish a close correlation to base case
and proposed case energy requirements of the dwelling home between the software modelling
packages.
Both the DEAP and SBEM software modelling packages were developed by the Irish and English
governments respectively in order to access and develop awareness of the energy efficiency of
dwelling homes. This was done as a means of gathering knowledge in order to implement strategies
to achieve set CO2 emission regulations. As these programs were developed for similar reasons,
similarities can be seen between both.
RETscreen also assesses the technical and environmental aspects as well as being a powerful tool
for providing financial analysis.
Introduction
Energy is a valuable resource which is
required in our everyday lives at home, for
transport and in work. Energy is becoming
more expensive to purchase and is producing
harmful by-products such as green house
gases which is damaging our environment.
The main source of fuel for energy production
is in the form of fossil fuels. This is an
exhaustible fuel which will eventually be
depleted. As a result of this the efficient use of
energy is a growing concern.
The purpose of this project was to examine the
energy efficiency of a dwelling home in its
existing state as its base case and to analysis
the feasibility of implementing energy efficient
measures in its upgrade.
The energy efficiency upgrading measures
included upgrading the heat loss elements and
envelopes of the dwelling home to reduce heat
loss from poorly insulated elements. This
included:
 Increasing the insulation in the attic
space
 Applying external insulation to all heat
loss external wall elements
 Upgrading tungsten lamps to energy
efficient lighting (CFL’s)
 Upgrading poor efficiency boiler to
high efficiency boiler and providing
heating controls for full zone control of
heating system
 Providing solar panels to contribute
towards hot water demands.
Three independent software modelling
packages were utilised to examine the
technical and environmental aspects of the
building “Cloonbeg”, Castlefreke, Clonakilty,
Co. Cork.
These packages included:
1. RETscreen
2. Dwelling Energy Assessment
Procedure (DEAP)
3. Simplified Building Energy Modelling
(SBEM)

3. Nomenclature
kW Kilowatt = 1000 Watts
MW Megawatt = 1,000,000 Watts
kWh Kilowatt Hour = kW x Hours
HHV Higher Heating Value
Tonne 1000 Kilograms
CO2 Carbon Dioxide
Description
Premises
The premises is a 2 storey dwelling house
constructed 1990 circa with a 2 storey
extension constructed 2000 circa.
Photo 1: “Cloonbeg”, Castlefreke, Clonakilty,
Co. Cork.
The premises is located in a sheltered site
offering little wind potential but is situated
approximately 50m east of a stream. The
premises is facing in a southerly direction.
Photo 2: Ground floor plan of existing dwelling
house
Photo 3: First floor plan of existing dwelling
house
Software Packages

4. RETscreen was developed by the Canadian
Government and is currently operating on its
fourth version. It was developed in 1998 and is
a Microsoft Excel based software package
used to determine the feasibility of clean
energy projects and has the means to assess
a wide range of energy efficiency technologies.
The package includes an in-depth library
capable of assisting its interface user in all
energy assessment techniques. It is a powerful
tool that also has the capability of providing its
user with the ability to generate financial and
feasibility assessments for its projects.
Dwelling Energy Assessment Procedure
(DEAP) was developed by the Irish
Government to implement the assessment of
the energy performance of buildings. DEAP
software modelling package is used solely for
the assessment of dwelling homes.
It is a package that offers both the technical
and environmental assessment of the dwelling
home based on standard occupancy
assumptions and a range of technical
judgements based upon the views of various
expert organisations regarding the energy
efficiency impact of various building
components and attributes. In practice the
energy efficiency of a building depends on how
the occupants operate the building.
Simplified Building Energy Modelling (SBEM)
was developed by the British Government to
implement the assessment of the energy
performance of buildings. SBEM software
modelling package is capable of assessing the
technical and environmental aspects of both
domestic and non domestic buildings.
Energy Efficiency Measures
There are a number of energy efficient
measures available that can be used in the
upgrading of an existing home. Some of these
measures include upgrading heat loss
elements, upgrading heating systems including
heating controls, improving air tightness within
buildings, improving poor efficiency electrical
consuming devices with high efficiency
devices and by using renewable technologies
such as solar panels, hydro turbines, wind
turbines, heat pumps etc.
The measures implemented in the efficiency
upgrade of “Cloonbeg” consisted of:
 External wall insulation to improve U-
Value of wall envelope from
0.55W/m
2
K to 0.19W/m
2
K
 Additional roof insulation to improve U-
Value of roof envelope from
0.418W/m
2
K to 0.134W/m
2
K
 Upgrading of low efficiency boiler of
ɳ=0.808 to a high efficiency boiler of
ɳ=0.932
 Upgrading of heating control system
from programmer time clock to full
zone control to allow time and
temperature control of the heating
system and hot water system
 The provision of evacuated tube solar
panels to contribute to the hot water
demands
Grants are made available for the measures
implemented in this project under the home
energy saving scheme as provided by SEAI
(Sustainable Energy Authority of Ireland).
Measure Category Grant
Roof Roof Insulation €250
Wall Cavity wall
insulation
€400
Internal wall
insulation
€2,500
External wall
insulation
€4,000
Heating
Controls
High Efficiency GAS
or Oil fired Boiler
with Heating
Controls Upgrade
€700
Heating Controls
Upgrade
€500
BER
Assessment
BER After Upgrade
Works (Only one
BER grant per
home)
€100
Table 1 (SEAI Home Energy Saving scheme
Application Guide Version 2.0)
SEAI also offer a grant scheme to existing
homeowners under the Greener Homes
Scheme Phase III. Under this scheme they
offer grants of €250/m
2
(to max. of 6m
2
) for
Solar – Flat Plate and €300/m
2
(to max. of
6m
2
) for Solar – Evacuated Tube.
Survey Data
Please see Table 2 below showing data
collected from on-site survey.

5. Room Area (sq.m) Opening
opening
dimensions
(sq.m)
Glazing
Details Frame Gap direction
Draught
stripping
y/n
Chimney
or
Flueless
Open
Flues
Fans /
vents
Rads with
or w/o
TRVs?
Number
of Lights
Number of
Low Energy
Lights
GROUNDFLOOR
z0/0
1
Dining Room 16.76 Window 2.4 Double Glazed PVC 12 South y - - 0/1 1/o 2 0
Dining Room - Window 0.64 Double Glazed PVC 12 East y - - " " " "
Dining Room - Window 2.06 Double Glazed PVC 12 West y - - " " " "
z0/0
2 Kitchen 19.77 Window 1.28 Double Glazed PVC 12 East y - - 1/1 1/o 2 0
z0/0
3
Utility 7.58 Window 1.09 Double Glazed PVC 12 East y - - 0/1 1/o 1 0
Utility - Door 2.01 Double Glazed PVC 12 North y - - " " " "
Utility - Glazing 0.56 - - - - - - - - - - -
z0/0
4 WC 2.73 - - - - - - - - - 1/0 1/0 1 0
z0/0
5
Living Room 18.87 Window 2.55 Double Glazed PVC 12 South y 1 - 1/1 1/o 2 0
Living Room - Window 2.4 Double Glazed PVC 12 West y " - " " " "
Living Room - Window 0.64 Double Glazed PVC 12 North y " - " " " "
z0/0
6
Entrance Hall 8.19 Door 2.7 Double Glazed PVC 12 South y - - - 1/o 1 0
Entrance Hall - Glazing 1.07 - - - - - - - - - - -
z0/0
7 Garage 25.59 - - - - - - - - - - - 2 0
FIRSTFLOOR
z1/0
1
Bedroom 1 17.32 Window 1.44 Double Glazed PVC 12 West y - - 0/1 1/o 3 0
Bedroom 1 - Window 1.67 Double Glazed PVC 12 South y - - " 1/o " "
z1/0
2 Ensuite 2.6 - - - - - - - - - 1/0 1/o 1 0
z1/0
3 Landing 11.74 - - - - - - - - - - - 1 0
z1/0
4 Bedroom 2 12.29 Window 1.44 Double Glazed PVC 12 East y - - 0/1 1/o 2 0
z1/0
5 Ensuite 5.71 Window 0.72 Double Glazed PVC 12 North y - - 1/1 1/o 1 0
z1/0
6 Bathroom 4.79 Window 0.72 Double Glazed PVC 12 North y - - 1/1 1/o 1 0
z1/0
7 Hall 4.01 - - - - - - - - - - 1/o 1 0
z1/0
8 Bedroom 3 14.87 Window 1.44 Double Glazed PVC 12 South y - - 0/1 1/o 2 0
z1/0
9
Bedroom 4 13.34 Window 1.09 Double Glazed PVC 12 North y - - 0/1 1/o 3 0
Bedroom 4 - Window 1.09 Double Glazed PVC 12 West y - - " " " "
z1/1
0 Ensuite 2.28 - - - - - - - - - 1/0 1/o 1 0
z1/1
1 Hall 7.64 Window 1.09 Double Glazed PVC 12 North y - - - 1/o 1 0
Table 2: On-site data survey sheet

6. Findings
From inspection of “Cloonbeg” , the Building
Energy Rating (BER) using the DEAP software
(Irish Standard) at the time of inspection was
that of a D2 (i.e. 262.72 kWh/m
2
/yr)
At the time of inspection it was noted poor
building standards had been utilised during its
construction for energy efficiency which would
be reflective of the time at which it was built.
It was noted that the installed boiler had been
upgraded from its original boiler but was still of
poor efficiency. The use of condensing boilers
is common practice in current building
standards and would improve the overall
energy efficiency of the dwelling home.
It was noted that a programmer/time clock was
present with no room thermostats present to
control the heating system at the time of
inspection. Installing a new time and
temperature zone control system would allow
for much improved control of the heating
system providing improved living conditions
and improving the overall energy efficiency of
the dwelling home.
The water cylinder had lagging jacket
insulation and no thermostat at the time of
inspection. A new factory insulated water
cylinder with a thermostat adequately sized to
provide sufficient hot water for the estimated
number of occupants of the dwelling house
would be more efficient and improve the
overall energy efficiency. A water cylinder
incorporating a twin coil system is required
with the provision of solar panels.
It was noted that standard lighting is used
throughout the dwelling. Replacing this lighting
with low energy efficient lighting will save
energy use throughout the year and improve
the overall energy efficiency of the dwelling
home.
It was noted that external walls were of cavity
block construction been constructed in the
early 1990’s with limited insulation. It was also
noted that limited insulation was been utilised
in the roof space between and over the ceiling
joists. Insulation levels can be improved
throughout. This will be shown to be feasible in
the ceiling area and external walls.
Chimneys are an area which lose large
quantities of energy. The heat rises up and
passes out through the open chimney. If these
openings are reduced to an open flue this will
reduce the overall heat loss.
Fireplaces are also very inefficient with an
efficiency rating of 30%. Improving on this by
using other means of secondary heating
systems which are more efficient such as 65%
efficient stove room heater will improve the
overall energy rating of the dwelling home.
These heating systems will also allow the
chimney used for open fires to be reduced to a
flue for other secondary heating systems that
are more efficient thus improving your overall
energy efficiency.
Primary Energy Demand = 262.72kWh/m
2
/yr
Improvement Primary
Energy
Demand
(kWh/m
2
/yr)
CO2
Emissions
(kgCO2/m
2
/yr)
Upgrading
external wall
insulation to
provide a U-
Value of
0.19W/m
2
K
226.02 52.72
Upgrading
roof insulation
to provide a U-
Value of 0.134
W/m
2
K
211.99 49.37
Upgrading of
boiler to a high
efficiency
boiler of
ɳ=0.932
191.81 45.11
Upgrading of
heating control
system to full
zone control
system
157.08 36.90
Provision of
evacuated
tube solar
panels to
contribute to
the hot water
demands
144.46 34.36
Table 3: Improvements indicated on reducing
step basis of proposals implemented using
DEAP Software

7. Results
The energy efficiency was calculated for
“Cloonbeg” dwelling home using 3 different
software modelling packages as mentioned
above. Please see screenshots of the results
obtained from each package for the base case
and proposed case scenarios below.
Screenshot 1: Base Case Results (DEAP
Software)
Screenshot 2: Proposed Case Results (DEAP
Software)
From the DEAP software results it can be seen
that Primary Energy Demand reduced from
262.72kWh/m
2
/yr to 144.46kWh/m
2
/yr
subsequent to the implementation of the
proposed measures mentioned above. These
implementations offer a saving of
118.26kWh/m
2
/yr on the Primary Energy
Demand with a total saving of
27.11kgCO2/m
2
/yr on the CO2 emissions.
This offers a total financial savings of
€1561.30 per year based on a rate of
€0.14/kWh of electricity and €0.07/kWh of LPG
fuel.
With a budget cost estimate of €21,850 –
incentives which amount to €5,922 the total
expenditure comes to €15,928. This provides a
pay back period of 10.2 yrs.
Screenshot 3: Base Case Results (SBEM
Software)
Screenshot 4: Proposed Case Results (SBEM
Software)
From the SBEM software results it can be
seen that Primary Energy Demand reduced
from 288.88kWh/m
2
/yr to 145.65kWh/m
2
/yr
subsequent to the implementation of the
proposed measures mentioned above. These
implementations offer a saving of
143.23kWh/m
2
/yr on the Primary Energy
Demand with a total saving of
33.49kgCO2/m
2
/yr on the CO2 emissions.
This offers a total financial savings of
€1,172.19 per year based on a rate of
€0.14/kWh of electricity and €0.07/kWh of LPG
fuel.
With a budget cost estimate of €21,850 –
incentives which amount to €5,922 the total
expenditure comes to €15,928. This provides a
pay back period of 13.6 yrs.

8. Screenshot 5: CO2 Emissions Analysis
(RETscreen Software)
Screenshot 6: Financial Analysis (RETscreen
Software)
From the RETscreen software results above it
can be seen that there is a savings in CO2
emissions of 2700kgCO2/yr. The base case
CO2 emissions were 7.2tCO2/yr with the
proposed case resulting in 4.5tCO2/yr.
Based on a rate of €0.14/kWh of electricity and
€0.07/kWh of LPG fuel RETscreen gives a
financial savings of €1,208 per year. This
offers a return period of 10 years for the
investment.
Conclusions/Recommendations
From the above analysis it can be seen that
RETscreen offers the shortest payback period
of 10 years for the investment. This is only
slightly less than that of the DEAP software of
10.2 years. SBEM had the longest payback
period 13.6 years.
SBEM results show large savings in upgrading
lighting in comparison to the RETscreen
software and the DEAP software and appears
unrealistic when compared with hand
calculations for lighting also. SBEM results
also show very little savings achieved in space
heating upon implementing the energy efficient
measures. This also doesn’t correlate with
RETscreen and with DEAP software as well as
expected results. The cost of heating the
dwelling home is more significant than the cost
of lighting within the home therefore the results
generated by SBEM result in a longer payback
period than generated by the other two
software packages.
All three software packages show substantial
CO2 savings on the implementation of the
energy efficient measures which results in
significant savings on green house gases.
From the above calculations this project
lifetime would be considered a long term
investment with a significant payback period.
Without government incentives this project
would not be financially viable as payback
periods of greater than 18 years. The energy
efficient measures utilised in the project have a
limited lifetime and could be obsolete by the
time the investment is returned.
The implementation of the above mentioned
energy efficient measures did not upgrade the
dwelling house satisfactorily to conform to
current building regulation Technical Guidance
Document Part L. To conform with these
regulations additional measures would need to
be implemented in the form of upgrading the
heat loss element of the floor and providing a
source of renewable energy to provide
10kWh/m
2
/yr of the overall floor area of the
dwelling home, 4kWh/m2/yr of electrical
energy, or a combination of these which would
have equivalent effect. Such renewable energy
sources could include a wood fired
stove/boiler, wind turbine or hydro turbine to
name but a few. Some of these measures are
not suited to retrofitting and would not be
feasible.
Acknowledgments
The authors wish to thank Mr. Gordon Petrie,
Cork Institute of Technology, Chemical
Engineering Department for his assistance,
advice and direction throughout the year.
References
Sustainable Energy Authority of Ireland
Technical Guidance Document Part L
SBEM User Guide 3/12/10
Non-domestic Energy Assessment Procedure
(NEAP) Modelling Guide & SBEM Technical
Manual version 3.5.a
Dwelling Energy Assessment (DEAP) Manual
RETscreen Help Desk