Development of Sustainable Home using Net Zero Energy

This report explores the technologies and strategies for developing a sustainable home using net zero energy. It discusses the selection of low carbon materials, innovative construction processes, energy management, renewable energy sources, and recycling and reuse. The report also estimates the carbon emissions and costs associated with different materials and provides recommendations for achieving net zero energy homes.

Development of Sustainable Home using Net Zero Energy
DEVELOPMENT OF SUSTAINABLE HOME USING NET ZERO ENERGY
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Development of Sustainable Home using Net Zero Energy
Abstract
High energy consumption in the construction industry has warranted efforts to try to achieve
zero carbon emissions in buildings. This report in its various sections goes through the
various technologies that can be applied to achieve zero carbon emission homes. In the
methodology, two different materials, YH and RH, are selected to compare the embodied
carbon energy and the saved costs in both houses. Homer software is used to design on-site
renewable energy supply to achieve net zero emission over the service life of RH. The
simulation results are discussed, challenges explored and recommendations made.
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Development of Sustainable Home using Net Zero Energy
Table of Contents
Abstract......................................................................................................................................2
Introduction..............................................................................................................................3
2.1 Review low/zero carbon design technology......................................................................4
Selection of low carbon materials...........................................................................................4
Innovative Construction Process............................................................................................4
Management Operative energy consumption and consumption behavior..............................4
Renewable Energy..................................................................................................................4
Recycle and Reuse..................................................................................................................5
2.2 YH Details...........................................................................................................................6
Construction material used in YH..........................................................................................7
Construction Process used in YH...........................................................................................7
Details of heating/cooling, appliances and hot water for YH.................................................8
2.3 RH Details...........................................................................................................................9
Selection of construction materials.........................................................................................9
Selection of manufacturing constituents for RH that need less replacement/maintenance o. 9
Selection of construction process for RH...............................................................................9
The approach to reuse and recycle for RH...........................................................................10
The Energy management design to minimize consumption of energy during heating and
cooling..................................................................................................................................10
The energy management design to minimize the consumption for hot water, and
Appliances............................................................................................................................10
Selection for YH on-site renewable energy..........................................................................11
2.4 Estimating the annual and total carbon emission over the service life of YH and RH
..................................................................................................................................................11
Estimation of embodied carbon emission of YH and RH Construction Material................11
Estimation of carbon emission of YH and RH.....................................................................12
Estimation of carbon emission related to maintenance........................................................13
Estimation of carbon emission from wastes for our RH.......................................................14
Estimation of operating carbon emission with regard to the daily consumption of hot water,
and all appliances of YH and RH.........................................................................................15
Estimation of operating carbon emission in relation to the daily usage for heating and
cooling of YH and RH..........................................................................................................17
Summary of changes with reduction percentage in energy and carbon emissions...............18
2.5 Use HOMER to design on-site renewable energy supply.............................................19
2.6 Estimate cost and benefits off energy saving for RH in comparison with YH...........28
2.7 The feasibility and challenges of implementing RH......................................................28
References................................................................................................................................29
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Development of Sustainable Home using Net Zero Energy
Introduction
Energy consumption in the construction industry has been for a long time at a high
percentage of the total energy production on earth. Efforts towards accomplishing net zero
carbon emission buildings have taken over in recent times. Achieving a net zero carbon
emission building requires the annual net energy used by a building to be similar to the
level of renewable energy that the building does produce within its boundaries. This can be
realized by significantly decreasing utility of fossil fuels and minimizing all those
processes that produce greenhouse gases during the construction and maintenance on
buildings. Most zero carbon homes rely on the energy from the national grid, they however
need to return an almost similar amount of power. New buildings can be constructed to be
environmentally friendly and the existing ones retrofitted with technologies that are eco-
friendly, low in cost and energy efficient. This can lower carbon emissions as well as the
energy demands and mitigate overexploitation of natural resources. Greenery systems are
known to be low energy solutions that can be applied in the retrofit of existing buildings.
The other important factor to consider is the right material selection that; allow for low
carbon emission, are modern and more efficient, reduce consumption by using low energy
appliances, supplement power through addition of renewable energy sources and are
recyclable.
The aim of this report is to identify net zero energy solutions for homes by
establishing the various causes of carbon emission. This is done by comparing two
buildings that are different in terms of the selected materials, one referred to as YH and the
other RH. This aids in the calculation of the embodied carbon energy for both houses the
saved costs as a result of the use of renewable energy sources. Possible solutions in the
achievement of net zero energy homes will be recommended in the end. The challenges
encountered during the process shall also be explored.
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Development of Sustainable Home using Net Zero Energy
2.1 Review low/zero carbon design technology
Selection of low carbon materials
Reducing the embodied carbon for building is a simple practical method that can be
achieved by utilizing by low carbon materials and carbon sink. Low carbon materials can be
obtained from materials that poses low embodied energy and carbon (EEC) during the
production process, assembly and transportation. On the other hand, carbon sink can be
obtained from wood products. The harvested wood materials include cladding and flooring
materials, doors, window frames, furniture, rafters and beams. However, bamboo also
receive great attention and is considered to be tougher than soft steel. The widely used
bamboo product is the treated bamboo flooring. Examples of low carbon building materials
include green concrete, low carbon brick, green tiles, rammed earth walls, fly ash blocks
etc. (Anderson & Shiers, 2009).
Innovative Construction Process
To achieve net zero energy home, various innovation construction strategies must be
implemented in the design. This means various factors need to be considered in the design
such as day lighting by increasing the number of size of the fenestrations while ensuring that
wall to window ration is high, allowing natural ventilation and cross ventilation, envelope
airtightness, radiant cooling and allowing under floor supply of air, and ensuring that the
orientation of the building is facing the direction of wind to allow proper ventilation to
maximize on the quality of pure and clean air (Balzani, 2010).
Management Operative energy consumption and consumption behavior
The consumption of energy in our homes remain crucial factor to be looked into since
buildings have very limited influence on the power consumption in the house. The electrical
consumed in the buildings remain high despite the low occupancy. In order to help minimize
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Development of Sustainable Home using Net Zero Energy
the amount of operative energy in our redesigned building, there will be need to use energy
efficient appliances such as the LED lamps is mandatory. The HVAC system should be also
be installed with thermostat to help regulate the indoor temperatures automatically by
switching them on and off automatically when necessary. The occupants should also have a
discipline behavior towards energy consumption by using them sparingly to help achieve low
energy goal as stated in the Kyoto protocol of 1995 and backed up by the United Nation
Framework Convention on Climate Change (UNFCCC).
Renewable Energy
The sources of energy to be tapped for this kind of design to help in achieving low or net zero
energy are the natural sources of energy that can be replenished. These include solar energy
tapped from the sun using photovoltaic system and , wind energy, Renewable energy is
referred to as energy usually tapped from renewable resources, w harnessed from wind
turbines(Bergh, 2008). Another source of energy that has not been fully tapped into is the use
of biomass energy (Goswami, 2006).
Recycle and Reuse
Certain building materials can be easily recycled and reused such as stones, wood, water and
soil. Instead of depositing these wastes on the landfills which increases the emission pf
carbon, they can be recycled and reused for other purposes in the building. The water used in
the building can also be recycled and used for other purposes such as flushing the toilet,
watering plants, washing clothes and machines including other outdoor purposes. Plastic bags
can also be recycled to reduce the amount of solid waste on land (Borenstein, 2008).
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Development of Sustainable Home using Net Zero Energy
2.2 YH Details
Our YH is a 3 bedroom bungalow house located in Hawthorn VC in Melbourne which is
house model 7. The house plan has an area of 182.78m2. Below is the screenshot of the
house plan.
Isometric views from sketchup
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Development of Sustainable Home using Net Zero Energy
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Construction material used in YH
The screenshot below was obtained from energy plus and it defines the materials selected
for our YH. They include brick veneer, concrete, ceramic tiles for the floor, carpet,
insulation and plaster board materials for both wall and ceiling, and door material.
Construction Process used in YH
Materials used in the construction of YH elements were made of different materials as
shown in the energy plus screenshot below. These materials were arrangement from the
outside layer and moved towards the inside layer. These layers include;
 Exterior floor consisting of concrete and ceramic floor.
 Exterior wall consisting of brick veneer, air gap, insulation and wall plasterboard.
 Interior walls consisting of insulation sandwiched between wall plasterboard

 Exterior roof consisting of roof tiles
 Interior ceiling consisting of insulation and ceiling plasterboard.
 Exterior window which is single glazed
 Exterior door made of timber
Details of heating/cooling, appliances and hot water for YH
HVAC system will have to be introduced in our YH to help in regulating the indoor
temperature in order to achieve thermal comfort with its constant heating set point set at
20 degrees Celsius while constant cooling set point at 24 degrees Celsius.. There are a
number of appliances that will be used in the house such as refrigerator, washing machine,
electric cooker, iron, computers, light, heater, microwave, television, dishwasher etc. the
hot water will be heated by either immersed heater or electric heater for use.

2.3 RH Details
YH building will be redesigned in an attempt to achieve net zero energy home with the same
layout plan, location and method used in construction.
Selection of construction materials
Materials selected for our RH are shown in the screenshot below as defined in the energy plus
software. The materials chosen are more likely to achieve our main goal of reducing carbon
emission in our home due to their low carbon content. This materials include REBricks, POP
wall plasterboard, wood carpet, Mangalore roof tile, door material, rigid polyurethane
insulation, low carbon concrete, glass wall wool insulation, mineral fibre ceiling, double
glazed window, ceramic.
Selection of manufacturing constituents for RH that need less replacement/maintenance o
To achieve less maintenance and replacement in YH, durable materials and sustainable
resources of energy were chosen to reduce carbon emission and less cost spent on energy
respectively.
 Electrical appliances should be energy efficient
 Water management strategies should be implemented

 Plumbing should be done appropriately to avoid any future leakage
Selection of construction process for RH
This category entails design and building, construction methods, selection of materials and
outcome of the construction. Choice of the right material is determined by some processes
focused on minimizing carbon emission. Different layers of materials were used to construct
the building elements in order to achieve the desire results as shown in the screenshot below
obtained from energy plus.
The approach to reuse and recycle for RH
The following materials are recyclable in RH; tiles, blocks, timber for the window frames,
glass wool recycled to form an insulation material and plasterboard recycled through grinding
and mixing with water to produce new plasterboard. Filing of the small craters resulting from
construction can done using pulverized blocks.

The Energy management design to minimize consumption of energy during heating and
cooling
Appliances with 5 star ratings are effective in terms of low power consumption and can be
used so as to reduce a building’s net energy consumption. Natural thermal comfort can also
be enhanced through insulation of the walls rather than relying on an energy consuming air
conditioning unit. Moreover, cross ventilation and maximum use of natural lighting will help
in saving the energy costs.
The energy management design to minimize the consumption for hot water, and
Appliances
By utilizing LED bulbs for lighting rather than fluorescent tubes energy costs are saved. The
LED bulbs have 5 star ratings in RH and hence desirable for low energy consumption.
Selection for YH on-site renewable energy
Sunlight and wind energy are renewable sources which are easily available for use in a home
setting. The solar energy can be tapped during the day by photovoltaic cells, solar heaters or
concentrated solar power. The photovoltaic cells apply the photoelectric effect for conversion
of light rays striking the panels into electrical direct current. These renewable sources are
sustainable and save on energy relat
ed bills.
2.4 Estimating the annual and total carbon emission over the service life of YH and RH
Estimation of embodied carbon emission of YH and RH Construction Material
The approximate area of the house model is 182.78 m2, with a wall heights of 3metres. The
ceiling area is 192 m2 and the windows opening area 22.94 16.8 m2.

YH material
Embodied carbon emitted by YH in the building life span for 40 years is estimated at; 403,
470.01 kg CO 2.
Annually EC = 403, 470/40 = 10, 086.75kgCO2
RH materials

Embodied carbon emitted by RH in the building life span for 40 years is estimated at; 57,
419.01 kg CO 2.
Estimation of carbon emission of YH and RH
First carbon energy is converted to embodied carbon using the formula below
1 MJ = 0.098 KgCO2
Internal walls with plaster finish= 907 MJ/m2*162.78 =147641.46*0.098 = 14468.86KgCO2
Concrete slab = 644 MJ/m2*182.78=117710.32*0.098 =11535.6114 KgCO2
Ceiling brandering with plasterboard finish and roofing =272 MJ/m2*182.78 =
49716.16*0.098 = 4872.184 KgCO2
Brick wall with cavity: 861 MJ/m2*162.78 = 140153.58*0.098= 13735.05 KgCO2
Elevated floor level = 294 MJ/m2*182.78 = 53737.32*0.098 = 5266.257 KgCO2
Total embodied carbon will be the sum of the total carbon elements; 14468.86 + 11535.6114
+ 4872.184 + 13735.05 + 5266.257 = 49, 877.962
Therefore, total embodied carbon for our YH = 49, 877.962 KgCO2
Embodied carbon emitted annually = 49, 877.962/40 = 1, 246.95 KgCO2
Let us assume that embodied carbon in RH reduced by 38% during the construction process.
Therefore, the total carbon emitted by RH will be = 100% - 38% = 62%
= 62*49, 877.962/100 = 30, 924.34kgCO2
Embodied carbon emitted annually by RH = 30, 924.34/40 = 773.12KgCO2

Estimation of carbon emission related to maintenance
YH Maintenance
In a period of 40 years, the total amount of carbon that will be emitted due to
maintenance is 130, 521.01 KgCO2. Carbon emitted annually; 130,521.01/40 =
3,263kgCO2
RH Maintenance

In a period of 40 years, the total amount of carbon that will be emitted due to
maintenance is 45, 021.01 KgCO2. Carbon emitted annually; 45, 021/40 = 1,
125kgCO2
Estimation of carbon emission from wastes for our RH
The DOC table will be used to determine waste emission by identifying the different
wastes produced on daily basis. The table below shows the amount of waste produced in
tonnes by our RH.
The formula be used in calculating carbon emitted from wastes is stated below.
[(Q x DOC/3) – R] x 18.9
= (131.40 x 0.49) - 0.1314)*18.9= 1214 KgCO2 = 1.214 tCO2
Take note that waste emission factor is 25%.
Therefore, 0.8 x 25/100 = 0.20 tCO2
Therefore, the amount of carbon emitted annually will be the total sum = 1.4 tCO2
Total CO2 emitted for 40 years will be = 1.4 x 40 = 56tCO2
Annually waste emitted = 1.414kgCO2

Let’s assume that carbon emitted by waste in RH reduced by 30%. It therefore means out YH
emitted 100% of carbon from its waste.
Annually waste emitted in YH = 1.414 x 100/70 = 2.02kgCO2
Estimation of operating carbon emission with regard to the daily consumption of hot
water, and all appliances of YH and RH
YH Appliances showing their usage
Carbon emission will take place in two scopes, scope 2 and 3. Consider scope 2 has an
efficient factor of 1.22 KgCO2/KW per hour while scope 3 has am efficient factor of 0.08
KgCO2/KW per hour.
Scope 2 = 31043.25 x 1.22 = 37872.765 KgCO2
Scope 3 = 31043.25 x 0.08 = 2483.46 KgCO2
Carbon emitted yearly by YH will be;
37872.765+2483.46 = 40356.225 KgCO2 = 41 tCO2

Annually emitted carbon = 40, 356.225/40 = 1, 008kgCO2
Introduce more energy efficient appliances in our RH
Scope 2: 6945.95 X 1.22 = 8474.059 KgCO2
Scope 3: 6954.95 X 0.08= 556.962 KgCO2
Total carbon emitted
8474.059 + 556.962 = 9030.455KgCO2
Annually emitted carbon = 9030.455/40 = 225.76kgCO2

Estimation of operating carbon emission in relation to the daily usage for heating and
cooling of YH and RH
YH embodied energy for heating and cooling.
RH embodied energy for heating and cooling

The results shows a significant drop in the amount of energy used in heating and cooling BY
39.3 %. This means that we achieved our goal of reducing the cost of energy in our RH
Summary of changes with reduction percentage in energy and carbon emissions
The tables above shows the comparison of YH and RH in relation to carbon emitted with
their reduced percentage based on the results obtained above
The results obtained shows a positive reduction in all factored elements, thus,
cumulatively helping in achieving net zero energy home. It is also a clear indication that
when we use materials with low carbon content, well rated energy appliances, having
installed hot water system, having proper waste management system and less
replacement/maintenance elements can prove to be advantageous in meeting the
objectives of achieving low carbon emission in residential homes.

2.5 Use HOMER to design on-site renewable energy supply
In this chapter, the description of the project is stated after which the site location was
identified to be Hawthorn VIC in Melbourne. What followed was the hourly energy
consumption in Kwh obtained from RH in energy plus are loaded into HOMER software as
electric loads before other components are added into the scheme.
Electrical Load input
Components
 Grid system

 PV system
Gives the cost of installing the system, replacing and O&M
 Converter
Gives the cost of installing the converter, replacing and O&M

 Storage
Battery is necessary for storing surplus energy. Homer gives the cost of installing the battery,
replacing and O&M
 Wind Turbine
Homer gives the cost of installing the wind turbine, replacing and O&M
Resources

Renewable energy sources for achieveing net zero goals
Solar resource
 Wind resource
Shows the average wind speed for every month
Project detail

 Economic
Simulation Results
 Cost Summary

 Cash flow
 Compare Economics

 Electrical

 Renewable Penetration
 Generic flat plate PV

 Grid
 System Converter

Emission
The results above shows that 40 years of life service of the house gives a net cost of
$44,135.
2.6 Estimate cost and benefits off energy saving for RH in comparison with YH
The photovoltaic scheme produces 20.23kWh/day. The average consumption of energy in the
house is 8 kWh per day. This means the excess energy in a day will be 12.23kwh per day.
The excess energy can be sold to the grid a cost of $0.35 per kW. Therefore, the profit gained
per day will be $4.2805 per day
Payback period will be = total initial investment/total pay per year
= 46500/1562.38
=29.8 years
This means that the initial capital will be attained after a period of 29.8 years

2.7 The feasibility and challenges of implementing RH
It is quite difficult to achieve a net zero energy house without using today’s energy and also
going by the occupants’ expectations. A right setting, building and team is necessary to
achieve a net zero energy house. The green construction materials like Photo Voltaic (PV)
cells are also expensive especially for taller buildings, a building of less than four stories
would be more manageable in regards to cost. Materials selected for construction need to be
considered on the lines of safety, energy efficiency, recyclability and availability.

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