In this passive solar home design project we were tasked with building a tiny house that used the least amount of energy possible while still allowing lots of light into the house throughout the year. In this project we used a series of projects while building the house to help us better understand day lighting techniques and different renewable energy sources. Below you find our project and the multiple labs that we did to better understand and produce our project.
Hot Water Heater
The hot water heater project helped us by teaching how the sun's heat can be used in many ways. During this project we were tasked with building a water heater that could heat water without anything but the sun's energy. My group and I decided to bend copper piping into an "S" shape and run it through a shoe box wrapped in aluminum foil. Our plan was to have the sun's light reflect around the aluminum foil and hit the copper piping which would have the water sitting in it and heat up our water. Although the plan was well thought out. The water heater did not work that well due to the leaks in the connection points which reduced our water quantity and the slightly overcast day which prevented the copper piping from getting the maximum amount of exposure to sunlight. In total our water increased by 3*C. Below you can see a blueprint of the water heater my group and I created.
Day-lighting Techniques and Experimental House
This lab thought us about light usage inside and outside houses throughout different points of the year. We learned about sun angles and how different types of windows allow different amounts of light into the house. Our goal in this lab was to build a model house that had the most variety of day lighting techniques and types of windows to see which one, or combination of a few worked the best at all the times of the year. My group and I built our model houses out of cardboard and cut windows into the sides. The windows that we tested were regular, clerestory, light self, solar tube, and skylight. We also added different colors to our walls to test other day lighting techniques. We tested white, yellow, brown, and black walls. What we found is that regular windows at 4ft above the ground and clerestory windows 2ft below the ceiling with a room that has white walls was the most lit at the most times of the year. This combination of windows and paint allows lots of different angles of light in while the white walls reflect the light around the room for a long time instead of absorbing the light like a darker color. Below you can see our results in a table format.
Materials Heat Testing Lab
During the materials heat testing lab my group tested which materials are the best insulators by heating up a piece of iron to 140*F and placing it in a cardboard box that had a type of insulation lining the walls. Other groups tested the heat capacity of materials by shining hot lights onto a material and took temperatures at even intervals. My group and I placed the piece of iron into the box and waited 15 minutes to take the final temperature. We tested fiberglass insulation, rigid foam, carpet insulation, jeans, cotton, carpet, and spray foam. We found that the fiberglass insulation worked the best because the final temperature of the hot iron after the the 15 minutes in fiberglass insulation was 98*F. Only dropping only 42*F from its starting temperature. My group and I also concluded that rigid foam worked the second best followed by, (in order) carpet cushion, spray foam, carpet, cotton, and jeans. Below you can see our data with a numbered list of best insulators to worst insulators.
Building Design
Our final part of the project was to build our tiny home. We were tasked with building a tiny home that is energy efficient and low cost but still comfortable and safe. My group and I decided to build our solar home on the Stinson beach water front which eventually became a challenge for us due to the sandy conditions which made it hard to lay foundation for our house. We tried to incorporate all of the aspects we learned in the previous labs by adding regular and clerestory windows with white walls and using fiberglass insulation which we found worked the best in the materials heat testing lab. During the design process we made blueprints, floor plans, a 3D model, a spreadsheet of all the costs in our home and finally a power point to present our work.
Here is my spreadsheet of all the costs for the tiny house. This includes all the materials and appliances for inside and outside the house.
Generation of Electricity
In this lab we learned about alternative forms of energy especially wind power. My group and I created many forms of windmills on horizontal and vertical axis wind turbines. We created turbines with four blades and cups at the end and we also created light wind turbines with no connector and only two blades. We tested all of these wind turbines on 3 different levels of wind power. Level one which was a small fan at the slowest wind level. Level two which was a small fan at the highest wind level and level 3 which was a leaf blower at it's lowest speed. We found that the small light fans produced the most electricity because they spun the fastest without the heavy connector slowing it down. We found that the smallest number of blades and the lightest amount of material worked the best even though it wasn't as stable. On levels one and two the small light wind turbine produced the most electricity but at level 3 became unstable and flew off. With our light design we traded stability for more electricity on lower wind levels.
Content
Radiation: Radiation is energy that comes from a source that travels through some material or space. My group and I used radiation when we used heat from the sun to heat our house and radiation was also absorbed in the high heat capacity materials we used in the house.
Conduction: Conduction is the transfer of heat through two objects touching. Conduction is used in water heaters to transfer heat between wires and pipes and eventually to the water.
Convection: The movement of heat within a fluid hotter less dense fluids rise and colder less dense fluids sink to the bottom.
Insulation: Insulation is when materials with high heat capacity take in the heat being released and send them back to the object with the heat loss. This keeps the object losing heat hotter longer. Insulation was used in our project when we insulated our tiny house with fiberglass. The fiberglass insulation will keep heat in the house during the winter and keep the heat out of the house in the summer time.
Specific Heat Capacity: The heat required to raise the temperature of the unit mass of a given substance by a given amount. Materials with high heat capacity store lots of heat and release it slowly over a long period of time. While materials with a low heat capacity are the opposite they barely store any heat and reflect most if not all the heat directed at the material. We used a tin roof in our project due to its low heat capacity which will keep our house cool in the summer.
Heat: The quality of being hot; high temperature. Heat is key to life on Earth and without there would be no universe or anything in it.
Conduction: Conduction is the transfer of heat through two objects touching. Conduction is used in water heaters to transfer heat between wires and pipes and eventually to the water.
Convection: The movement of heat within a fluid hotter less dense fluids rise and colder less dense fluids sink to the bottom.
Insulation: Insulation is when materials with high heat capacity take in the heat being released and send them back to the object with the heat loss. This keeps the object losing heat hotter longer. Insulation was used in our project when we insulated our tiny house with fiberglass. The fiberglass insulation will keep heat in the house during the winter and keep the heat out of the house in the summer time.
Specific Heat Capacity: The heat required to raise the temperature of the unit mass of a given substance by a given amount. Materials with high heat capacity store lots of heat and release it slowly over a long period of time. While materials with a low heat capacity are the opposite they barely store any heat and reflect most if not all the heat directed at the material. We used a tin roof in our project due to its low heat capacity which will keep our house cool in the summer.
Heat: The quality of being hot; high temperature. Heat is key to life on Earth and without there would be no universe or anything in it.
Day Lighting Techniques
. Clerestory Windows: Can be used to allow lots of light in that comes in at a higher angle. They work well in the winter but probably should be blocked by a overhang in the summer months.
Light Shelves: Light shelves are very useful on windows when light needs to be reflected upward. The light shelves also catch more angles of light throughout the year.
Solar Tubes: Solar tubes catch high angles of light in the summer time and break up light and spread it across the room. The bad thing about them is that they don't catch a lot of low angle light which is not useful in the winter time.
Skylights: Skylights allow lots of light into big rooms in the summer months. They will also allow light into rooms in winter months if angled correctly. The downside is that they are a big pane of glass which can break if things fall on them or if snow piles up on them they could break.
South Facing Windows: To have a useful solar house the majority of windows need to be south facing due to the fact that the sun in the Northern Hemisphere goes across the sky to the south of us.
Solar Angles during different seasons: During summer months the sun is higher in the sky and is more direct which makes the surface of the Earth hotter. During the winter the sun is lower in the sky and the sun rays are less direct. Below you can see a blueprint of the overhang we created to black out the summer rays but let the winter rays of sunlight into our house. The sun angles change because the Northern Hemisphere tilts toward the sun in the summer and away from the sun in the winter. This change affects the angle of the sun's rays hitting the Earth at different points of the year.
Light Shelves: Light shelves are very useful on windows when light needs to be reflected upward. The light shelves also catch more angles of light throughout the year.
Solar Tubes: Solar tubes catch high angles of light in the summer time and break up light and spread it across the room. The bad thing about them is that they don't catch a lot of low angle light which is not useful in the winter time.
Skylights: Skylights allow lots of light into big rooms in the summer months. They will also allow light into rooms in winter months if angled correctly. The downside is that they are a big pane of glass which can break if things fall on them or if snow piles up on them they could break.
South Facing Windows: To have a useful solar house the majority of windows need to be south facing due to the fact that the sun in the Northern Hemisphere goes across the sky to the south of us.
Solar Angles during different seasons: During summer months the sun is higher in the sky and is more direct which makes the surface of the Earth hotter. During the winter the sun is lower in the sky and the sun rays are less direct. Below you can see a blueprint of the overhang we created to black out the summer rays but let the winter rays of sunlight into our house. The sun angles change because the Northern Hemisphere tilts toward the sun in the summer and away from the sun in the winter. This change affects the angle of the sun's rays hitting the Earth at different points of the year.
The red lines are the more direct rays from the summer months and the blue lines are the less direct rays from the winter months. The black lines are our walls and overhang. Our overhang is placed at 114* to block out the summer sun but allow the winter light in to our windows which are shaded in black.
Reflection
This project taught me many things about solar energy and the different forms of energy that can be used to power our homes. This topic in my opinion is a growing need in an overpopulated world where energy is key to survival. If humans learn to use renewable energy and make it more efficient than the human race and achieve many more advances in other fields. One positive thing I learned from this project was the different day lighting techniques and how they can positively or negatively affect your home. Learning about these made me feel motivated to find more techniques and maybe some day have then used in my own home. One negative from this project was the time management doing this website update. I did not manage my time wisely and had to finish the website on the day it was due. I learned that if little chunks of the website are done every day it will be easier to finish. This was a great project that I learned so much from. I am so excited to continue research down this path of physics and engineering.