Zero Energy Home

Samantha AherneSarah KrisherJordan Matteo

Jim Wolfe

October 14, 2010

Project Overview

Our Goals:1.To create the most sustainable zero

energy home possible, while keeping some of the ideas from our dream homes.

2.To be able to understand the reasoning behind the decisions we make in building our zero energy home.

Most Important Features:

• Solar Water Heater• Solar Panels• Windows• Size (square footage)• Number of levels• Size of photovoltaic system• Energy efficient appliances

Project Overview

Project OverviewLocation (city, state) Harrisburg, PA

House size (floor area in square feet)

1,334.25 square ft.

Number of floors 1

Number of occupants Up tp 4

Number of bedrooms Up to 3

Type of heating system (forced air, hydronic, radiant floor, heat pump, etc.

Electric heat pump (because it has AC)

Main heating fuel (electricity, natural gas, wood, oil, etc.)

Solar electricity

Size of photovoltaic system (kilowatts)

6 kw

Solar water heater (yes or no) Yes; enough for four people (2 solar water heaters)

R-value of wall insulation R-19; 1’’ foam

R-value of ceiling insulation R-40

Ventilation air heat recovery (yes or no)

Yes

Predicted or measured annual energy use

ZERO!

• Solar water heaters were a common feature of most of the houses

• Many of the homes researched had variations of heat pumps, mostly geothermal heating systems

• LED lighting• All the houses had high R-values for

the walls and ceiling• Ventilation Air Heat Recovery was

used

Research Summary

Envelope:• We tried to limit the number of walls separating the rooms

because when the sun shines through the windows, the more open the house is the more direct gain we will harness from the sunlight.

• A one story house is much easier to make efficient because with a multiple level house, you have to generate more energy to heat the house and keep it running.

• We wanted as many windows in our envelope as possible for many reasons. Not only is it aesthetically pleasing, but it allows the sun to directly shine into the rooms and allows the occupants of the house to cut back on using appliances such as lamps. Another reason more windows has greater efficiency is because it allows the house to be heated more by passive solar than by the heat pump.

Key Decisions

Appliances:• Refrigerator- Frigidaire 18.2 Cu. Ft. Top Mount Refrigerator because it is the cheapest option

of all the refrigerators with the same amount of utilities. Also, it is the most energy efficient with only 383 kWh/yr. It only costs $41 per year.

• TV- Panasonic TC-L32C12. Although it is not as efficient as the 19” LG, it’s almost twice as big and has a lower stand-by rate. Figuring that the TV will be off more often than it is on, and won’t be on for 5 hours every day, the extra cost is worth it for the extra features. Also, the television is used which helps support the recycling effort.

• Dishwasher- Frigidare Professional 24” tall tub, built-in, stainless steel dishwasher. The difference in efficiency is due to the water saved by the more efficient models. The more efficient models save roughly 10 gallons a wash, which means they use much less hot water.

• Washing Machine- Frigidaire Affinity 4.4 Cu. Ft. Front Load Washer Featuring Ready Steam™. Although the washer is one of the more expensive ones, it is the most energy efficient, and costs the least amount per year (except for one, but that washer is not nearly as energy efficient). Along with efficiency, it also has many more options and qualities of a good washer than the other ones.

Key Decisions

HVAC:For our house we chose to use an electric heat pump. Electric heat pumps have high efficiency, with 200-300%, meaning that they generate 2-3 units of heat for every unit of electricity. Another reason we chose this is because electric heat pumps can also be used for air conditioning in the summer while electric resistance heat provides no cooling and is less efficient. Even though an electric heat pump is more expensive than electric resistance heat, the money we save by decreasing our photovoltaic system compensates for the difference. Our house is also very tightly sealed to prevent heating and cooling loss through air changes per hour.

Key Decisions

Solar Technologies:• Solar panels- 175 kW sharp solar panels 32 inches X 60

inches; 35 of them for a 6 kW photovoltaic system– Due to the structure and zero energy properties of our house,

a 6 kW PV system gave us a net zero energy use annually. – In the summer, we produce excess solar electricity which

makes up for the electricity we must pull from the grid in the winter, making the house a zero energy home.

• Solar water heater- We used two two-person solar water heaters to produce enough hot water so that four people can live comfortably. They are positioned on the roof alongside the solar panels.

• Solar electricity- achieved through the solar panels placed on the roof.

• Windows- Triple Low E windows were used. They are highly insulated and allow a lot of solar energy to pass through them.

Key Decisions

Behavior:• We are using energy efficient appliances to

continue in the efforts to cut back on energy usage.

• No garage was necessary for our home because the homeowners aren’t using cars, just public transportation!

• Simple things such as water conservation, monitoring room temperature so that the heating/cooling systems aren’t carelessly used, not turning lights and TV on when they aren’t needed, and recycling are a few behaviors practiced.

Key Decisions

Through our class experiment with the Styrofoam box, we learned about the effects of air changes per hour and how a tightly sealed house experiences less air changes per hour and therefore requires less heating/energy. Variables such as wind can affect these air changes as well.

Key Decisions

SketchUp model

SketchUp model

SketchUp model

SketchUp modelSeptember 21st – Autumnal Equinox March 21st – Vernal Equinox

SketchUp modelJune 21st – Summer Solstice December 21st – Winter Solstice

Physical

Physical

Sarah’s Favorite Feature:

I really like how open the main room is because with all the windows it makes the house appear larger and more spacious.

Summary of Design

Sammy’s Favorite Feature:

• I liked how we added a lot of windows to the design because that makes the house seem more open and bright.

Summary of Design

Jim’s Favorite Feature: I like the Photovoltaic System and how it makes our house a Zero Energy Home. I also like the solar water panels because it contributes to the zero energy design.

Summary of Design

Jordan’s Favorite Feature: I liked how we agreed on a design for the house that allows the roof to hold a 6 Kw system to support the house. This system was enough to make our home a Zero Energy Home without being extremely complex.

Summary of Design

• Greatest Challenges:– Building the roof • Getting the right angles and the overhang was difficult

– Sizing the voltaic system to match the energy needs

– Designing the layout to get as much open space as possible, while still getting all the rooms to fit within the house

Summary of Design

Reflection

At first, we started with this rough layout. Through this drawing we learned all the systems in the house are tied together. All electric appliances throw off heat. More systems than you think require a water heater and electricity.

• We have learned that it is possible to have the house of your dreams while still living in a zero energy home and maintaining a sustainable lifestyle.

• Although it requires a lot of effort and innovation, it can be done without the extreme costs, direct (expenses) and indirect (lifestyle choices), as some may think.

• You can still live comfortably in a zero energy home. • More efficient appliances and insulation drastically changes

the energy use of the house• It is necessary that our world makes these changes so that

we don’t deplete resources and permanently damage the earth.

Reflection