Sample CVE80010 Principles of Sustainability Report 3

CVE80010 Principles of Sustainability Report 3 Sample

Instruction:

In this assignment, you need to calculate the energy requirements of your dream house. In your house, there should have at least two bedrooms, one lounge, one kitchen, one laundry and one bathroom. One example of a house is provided in Figure 1.

Your tasks:

Make a sketch of your house. You may use CAD software or hand sketching. If you use hand sketching, it does not necessary to be scaled drawing. However, the dimensions should be mentioned in the sketch. Mention the size of the rooms in the report.

Calculate the total heat gain for your building.

How many light bulbs will you use in the house?

If you get the electrical energy from bituminous coal, how much CO2 emissions were there in summer?

What are the options available to reduce the heat gain? What percentage of heat gain can be reduced for each of the options? You need to show at least three options.
If you adopt all the options, what percentage of heat gain can be reduced?

Provide Justifications for each of your suggestions. For example, how the proposed solution reduces heat gain or heat loss? Present the detail calculation where appropriate. Provide reference for each of your suggested measures or action.

Solution

Sketch of Proposed House

In this sketch, the house is divided into different sections, including two bedrooms (Bed 1 and Bed 2), a lounge, a kitchen, a bathroom, and a laundry. Each room is labeled with its size, and the locations of windows and doors are indicated.

Bed 1 measures 3000 mm by 2500 mm and has a window in the North-West corner and a door in the West. Bed 2 also measures 3000 mm by 2500 mm and has a window on the East side and a door in the West. The lounge measures 3000 mm by 2500 mm and has windows on the West and North sides and doors on the North and South. The kitchen measures 1800 mm by 1800 mm and has a window on the East side. The bathroom measures 1600 mm by 1800 mm, and the laundry measures 1000 mm by 1800 mm. Overall, this sketch shows a simple and compact house design that includes all the necessary rooms for a comfortable living space.

Total heat gain of Building

To calculate the cooling load of the given house, we need to calculate the heat gain through each external element such as walls, windows, doors, and roof.
First, we need to calculate the area of each external element:

Area of Bed 1 = 7.5 m² (3m x 2.5m)
Area of Bed 2 = 7.5 m² (3m x 2.5m)
Area of Lounge = 7.5 m² (3m x 2.5m)
Area of Kitchen = 3.24 m² (1.8m x 1.8m)
Area of Bath = 2.88 m² (1.6m x 1.8m)
Area of Laundry = 1.8 m² (1m x 1.8m)
Total external wall area = 45 m² [(7.5m x 2) + (7.5m x 2) + (7.5m x 2) + 3.24m + 2.88m + 1.8m]
Total window area = 9.3 m² [0.54m² (Toilet) + 1.62m² (Kitchen) + 10.71m² (Lounge) + 1.62m² (Other)]
Total door area = 5.5 m² [2.5m² (Bed 1) + 2.5m² (Bed 2)]
Next, we need to determine the U-value of each external element using the table given:
U-value of external walls and doors = 2.7 W/(m².K)
U-value of windows = 6.4 W/(m².K)
U-value of roof = 2.6 W/(m².K)
Now, we can calculate the heat gain through each external element using the equations given:
Heat gain through walls = 45m² x 2.7 W/(m².K) x 6.0 K = 729 W
Heat gain through doors = 5.5m² x 2.7 W/(m².K) x 6.0 K = 89.1 W
Heat gain through windows = 9.3m² x 6.4 W/(m².K) x 11.0 K = 670.0 W
Heat gain through roof = 200m² x 2.6 W/(m².K) x 23.0 K = 11,960 W
The total heat gain through all external elements is:
Total heat gain = 729 W + 89.1 W + 670.0 W + 11,960 W = 13,448 W

Number of Light Bulb

There will be total 10 light bulb to be used in house.

Carbon dioxide Emission

To calculate the CO2 emissions from using electrical energy generated from bituminous coal, we need to determine the amount of energy used by the 10 light bulbs and the 13,448 W heat gain.

First, we need to convert the heat gain from watts to kilowatts (kw):
13,448 W ÷ 1000 = 13.448 kW

Next, we need to calculate the total power consumption of the 10 light bulbs. Let's assume that each light bulb has a power rating of 60 watts:
10 light bulbs x 60 watts = 600 watts or 0.6 kW

Therefore, the total power consumption of the 10 light bulbs and the heat gain is:
0.6 kW + 13.448 kW = 14.048 kW

Now, we can calculate the amount for the assignment helpline of CO2 emissions from using 1 kwh of electrical energy generated from bituminous coal, using the heat rate and CARBON DIOXIDE emissions data provided:

Average Operating Heat Rate for Bituminous Coal = 10,459 Btu/kwh
CO2 Emissions per million BTU of energy for Bituminous Coal = 205.7 pounds
To convert Btu/kwh to million BTU/kwh, we need to divide the heat rate by 1,000,000:
10,459 Btu/kWh ÷ 1,000,000 = 0.010459 million BTU/kWh

We can now calculate the CO2 emissions per kwh of electrical energy generated from bituminous coal:

CO2 Emissions per kwh = 0.010459 million BTU/kwh x 205.7 pounds/million BTU
CO2 Emissions per kWh = 2.1491 pounds/kWh

Finally, we can calculate the total CO2 emissions for the 10 light bulbs and the heat gain over the summer, assuming that they were used for 8 hours per day, 7 days a week, for 3 months (June, July, and August), which is a total of 2,016 hours:

Total energy consumed over summer = 14.048 kW x 2,016 hours = 28,273.408 kWh

Total CO2 emissions from bituminous coal over summer = 28,273.408 kWh x 2.1491 pounds/kWh

Total CO2 emissions from bituminous coal over summer = 60,793.087 pounds or approximately 30.4 tons of CO2 emissions.

Options available to reduce the heat gain

Heat gain is an inevitable occurrence in most buildings, especially during the summer months. However, it can lead to a significant increase in cooling costs and energy usage. Therefore, reducing heat gain is an important consideration for any building owner or occupant. Here are three options available to reduce heat gain and the percentage of heat gain reduction that can be achieved by each option:

Window Treatments

Windows are a crucial component of any structure because they let in natural light and connect the interior and outside areas. However, windows also contribute significantly to heat transfer, which raises energy consumption and utility costs. Window coverings can aid in this situation to lessen heat intake and the effects of outside elements including sunshine, wind, and temperature variations. Any sort of covering or material used to control the quantity of light, heat, and sound that enters a room through windows is referred to as a window treatment. For window coverings, there are several solutions available, each having pros and cons.

Window coverings have the potential to significantly minimise heat absorption through windows and boost a building's energy efficiency. Insulated panels, reflective films, and shades or blinds are all suitable choices that can reduce heat absorption to varied degrees. The kind and quality of the window treatment, the size and orientation of the window, and the local climate conditions may all affect how much heat gain is reduced. Nevertheless, window coverings can offer an economical and sustainable alternative for lowering energy use and enhancing interior comfort.

Insulation

Insulation is one of the most effective and widely used options available to reduce heat gain in a building. It refers to the use of materials with high thermal resistance to reduce the amount of heat transferred between the inside and outside of a building. Insulation can be used in walls, roofs, floors, and other parts of a building envelope to minimize heat gain and loss.

The percentage of heat gain that can be reduced with insulation depends on several factors, including the type and quality of insulation, the thickness of the insulation layer, and the climate conditions in which the building is located. However, it is generally agreed that insulation can significantly reduce heat gain, with estimates ranging from 25% to 80%.

There are several types of insulation materials available, including fiberglass, cellulose, mineral wool, and foam. Each of these materials has its own advantages and disadvantages, and the choice of insulation material depends on factors such as cost, effectiveness, and ease of installation.

Roofing

Roofing is a crucial aspect of building construction that plays a significant role in reducing heat gain in a building. There are various types of roofing materials available in the market that are designed to reflect heat and reduce heat absorption.

The percentage of heat gain that can be reduced depends on several factors such as the type of roofing material, the color of the material, the thickness of the insulation, and the local climate conditions. However, the above options have been proven to reduce heat gain significantly. Cool roofs, for example, can reflect up to 80% of the sunlight and reduce roof temperatures by up to 50 degrees Fahrenheit. Green roofs can reduce heat gain by up to 50%, depending on the thickness of the vegetation layer and the type of plants used. Insulated roofs can reduce heat gain by up to 60%, depending on the thickness and type of insulation used.
% Reduction in Heat Gain

The amount of heat gain that can be reduced, even if we use all three options (window treatments, insulation, and shading devices), will depend on a number of elements, including the type and quality of the materials used, the size and orientation of the windows and doors, and the local climate. However, it is generally reasonable to anticipate that if all three alternatives are taken, the overall heat gain can be decreased by up to 90%.

Up to 80% of heat gain can be reduced using reflective films or coatings. Up to 70% less heat gain may be achieved by using insulated panels or shutters, which also offer great insulation and light control. Up to 50% less heat gain can be achieved by using shading structures like awnings or overhangs. Combining all three alternatives will result in a considerable decrease in the overall heat gain, which will minimise cooling expenses and energy consumption. It is crucial to keep in mind that these choices can need an initial expenditure, and how cost-effective they are will depend on things like the size of the structure and the local environment.

Justification

Window treatments: Blinds, drapes, and other window coverings can assist lessen heat input or heat loss via windows. These coverings can reflect sunlight and block it from entering the room when closed during warm weather, which lowers the amount of heat that enters the area. They can provide as an insulating barrier in cold weather, keeping heat from escaping through the windows. The kind of window treatment and the material chosen will determine how much heat gain or loss may be stopped. For instance, reflecting blinds may reflect up to 85% of sunlight, while cellular shades are particularly good at keeping heat out of windows.

The use of reflective films or coatings is one of the best ways to lessen heat input through windows. These films' metalized constituents reflect heat and light, which lowers the quantity of heat that enters the space. Reflective films may be made to fit any window size or shape and are simple to install. Additionally, they are reasonably priced and over time, they can result in considerable energy savings. The kind and grade of the film, as well as the size and orientation of the window, can all affect how much heat gain is reduced by reflective films. Reflective coatings often minimise heat input by up to 80%, saving a substantial amount of energy.

Utilising blinds or shades is a further alternative for limiting heat penetration through windows. These window coverings may be changed to regulate the amount of light and heat that enters the room. They are constructed of a variety of materials, including cloth, wood, or vinyl. The shapes and patterns of shades and blinds vary, ranging from basic roller shades to intricate motorised systems. They are extremely effective in controlling light and may be positioned either inside or outside the window frame. Shades or blinds can reduce heat gain to a different degree depending on the material, colour, and thickness of the treatment. These window coverings often result in modest energy savings by reducing heat input by up to 50%.

Insulated panels or shutters are a third way to lessen heat absorption via windows. These window coverings are made to fit over the window and act as an insulator between the interior and the glass. Insulated panels may be created to fit any window size or shape and are often comprised of materials like foam, fibreglass, or reflective foil. They can offer good security, noise reduction, and light and noise control. Insulated panels, however, might cost more than ordinary window coverings and can need expert installation. The material and thickness of the panel, as well as the size and orientation of the window, may all affect how much heat gain is reduced with insulated panels. Generally, insulated panels can reduce heat gain by up to 70%, resulting in significant energy savings.

Insulation: In particular, insulation may stop heat from escaping through floors, walls, and ceilings of a structure. By minimising the amount of heat lost to the outside, adding insulation to these places can aid in maintaining a pleasant inside temperature. The kind and thickness of the insulation, as well as the environment where the structure is located, all affect how much heat loss can be stopped. Up to 20% more energy may be saved by boosting attic insulation from R-11 to R-49, according to the US Department of Energy.

One of the most prevalent and well-liked forms of insulation is fibreglass insulation. It is commonly put in batts or rolls between wall studs, ceiling joists, and floor joists and is constructed of glass fibres. Although it is affordable and simple to install, fibreglass insulation may not be as efficient as other insulation materials, particularly in locations with high humidity.

Cellulose insulation is often blown into walls and attics using a special machine and is comprised of recycled paper fibres. In comparison to fibreglass, it is more ecologically friendly and significantly reduces heat absorption. However, it costs more than fibreglass and can need expert installation. The qualities and techniques of installation of mineral wool insulation, which is formed of rock or slag fibres, are comparable to those of fibreglass. Although it is more costly, it is also more expensive than fibreglass and may be more effective at preventing noise transmission.

The more costly but highly effective method for lowering heat gain is foam insulation. To cover gaps and holes in walls and other places, it is often sprayed as a liquid that expands and hardens. Foam insulation offers an airtight seal that reduces heat absorption and loss, but it may not be appropriate for all types of structure and requires professional installation.

Shading devices: By preventing direct sunlight from entering a building, shading structures like awnings, pergolas, or trees can aid to lower heat gain. These gadgets may considerably lower the quantity of solar radiation that enters a structure in hot weather, which lowers the amount of heat that is absorbed by the building's walls and windows. The amount of heat gain that may be reduced depends on the building's orientation, size, and position of the shade device. The Lawrence Berkeley National Laboratory claims that shade equipment put correctly can cut a building's cooling energy use by up to 20%.
The following are some of the roofing options available to reduce heat gain in a building:

Cool Roofs: Cool roofs are designed to reflect sunlight and heat away from the building, reducing the amount of heat absorbed by the building. These roofs are usually made of materials that have high solar reflectance, such as white or light-colored materials. Cool roofs can reflect up to 80% of the sunlight and reduce roof temperatures by up to 50 degrees Fahrenheit, which can significantly reduce the heat gain in a building.

Green Roofs: Green roofs are another option for reducing heat gain in a building. These roofs are covered with vegetation, which absorbs the sun's energy and provides insulation to the building. Green roofs can reduce the heat gain by up to 50%, depending on the thickness of the vegetation layer and the type of plants used. They also provide several other benefits such as improving air quality, reducing stormwater runoff, and increasing the lifespan of the roof.

Insulated Roofs: Insulated roofs are designed to provide thermal insulation to the building, reducing heat transfer through the roof. These roofs are usually made of materials such as foam, which have a high R-value (thermal resistance) and prevent heat gain through the roof. Insulated roofs can reduce heat gain by up to 60%, depending on the thickness and type of insulation used.

Conclusion

In order to calculate the cooling load needed for a building, the total heat gain of the structure must be calculated. We can determine the heat gain through walls, doors, windows, and the roof by computing the area of each exterior element, figuring out its U-value, and applying the provided formulae. The CO2 emissions resulting from the usage of electrical energy produced from bituminous coal may then be calculated using the total heat gain. We can take into account solutions like enhancing insulation, putting in shading devices, utilising reflecting materials, or upgrading to more energy-efficient windows and doors to prevent heat gain. It is crucial to reduce heat gain to lower cooling costs, energy usage and CO2 emissions, and to create a more sustainable and energy-efficient building.

Reference

ASHRAE Handbook - Fundamentals, Chapter 28: Heat Transfer through Building Envelopes

ASHRAE Standard 90.1-2019: Energy Standard for Buildings Except Low-Rise Residential Buildings

Energy Information Administration. (2019). Average Operating Heat Rate for Selected Energy Sources.

Energy Information Administration. (2021). Carbon Dioxide Emissions Coefficients.

National Renewable Energy Laboratory. (2019). Residential Buildings Energy Consumption Survey (RECS).

U.S. Department of Energy. (2015). Building Energy Codes Program: U-Factor Table.

U.S. Department of Energy. (2018). Building Energy Codes Program: Fenestration U-Factor, Solar Heat Gain Coefficient, and Visible Transmittance.

U.S. Environmental Protection Agency. (2019). Energy Star Certified Light Bulbs.