Lesson7 Buildings Flashcards
How much of total greenhouse gases emitted are due to heating/AC?
7%
In the typical American home, what is the biggest user of electricity?
Air conditioning.
What will make this even greater?
Rising temperatures
In 2050 how much of all electricity will be used by AC?
45%
What is the irony of all of this?
Global warming will cause an ↑ in AC needs which will ↑ Global warming.
In 2020, how many air conditioning units were there in the world?
1.6 billion, unevenly distributed.
What is the energy source for most air conditioners?
Electricity, usually generated with fossil fuels.
What can we do until electricity becomes greener?
Buy more energy-efficient air conditioners.
What is the efficiency of the average AC sold compared to the best available?
50% of that widely available and
1/3 of the best
Why?
Because they are cheaper to buy
(but not cheaper to operate)
How can we fix this?
Rebates for buying better models.
Other than electricity, what harmful thing does AC do?
Emit refrigerants (F-gases)
What is Zephyr Innovations tackling?
A pound of refrigerants can produce a ton of CO2.
What percentage of US residents have AC?
India, Malaysia, Indonesia?
90%
10%
What are traditional cooling devices?
Heat pumps.
When were they developed?
Around 1900 by Willis Carrier
Where does heat want to go to?
From a hot space to a cold space.
What does AC do?
Take heat out of a cold space and put it in a hot space.
How do they cycle?
A compression cycle.
Thermodynamic cycle using refrigerants.
What does a refrigerant do?
It pulls heat out of a hot space.
Where does the heat go?
To a compressor as a gas where is is put under pressure.
Where is the big use of energy?
The compression.
Where is the hot gas sent?
Outside to a condensor where it turns back to liquid and eventually goes back to the evaporator.
There is an ideal efficiency.
Today, how do ACs normally perform?
At 12-14% efficiency
What needs to be fixed?
The vapor compression cycle.
What is Zephyr’s technology?
Got rid of the compression system.
It separates cooling and dehumidifying
What is a symptom of cooling and dehumidifying being the same process?
Freezing restaurants in hot places.
Trying to get the humidity down.
What de-humidifying system do they use?
A membrane system.
What cooling system are they using>
An evaporative system
What is eliminated?
A compressor
What replaces refrigerant in the cooling / evaporative system?
Water
What does the drying / membrane system use?
A water-based liquid desiccant.
What does a desiccant do?
Like silica gel, absorb moisture.
What is the opposite of a desiccant?
Humectant
Where did Zephyr get the $ to develop their concept?
The Global Cooling Prize.
Who established the prize?
The Rocky Mountain Institute, the government of India and others
What was unique about Zephyr?
They were one of 8 finalists.
Zephyr was 2 people competing against corps
Who have they partnered with?
Greentown Labs
What does Greentown Labs do?
It supports about 180 start-ups in 2 locations (MASS and TX)
What does Greentown call itself?
A Climate Tech Incubator
Does Greentown take equity in these start-ups?
No, they don’t profit from them.
What accounts for 1/3 of emissions from all buildings?
Furnaces and water heaters.
What energy do most furnaces depend on?
Natural gas, heating oil or propane.
What is heating oil?
Refined crude oil that comes from deep wells.
Worldwide how much energy for heating is provided by fossil fuels?
6 times more than electricity
What is the easiest way to de-carbonize heating?
Electrify with green electricity.
Electric heat pumps.
How do heat pumps work?
The same as ACs except they collect heat from the outside and transferring it indoors.
How are heat pumps better than they used to be?
They can operate in much colder climates
What is Aeroseal?
A company that helps elimate leaks of energy from buildings.
What percentage of energy used by buildings is leaked away?
50%
Why is this hard to solve?
It is built into the engineering ductwork of existing buildings
How do we typically solve this?
You get physical access to the ducts and find the leaks and caulk or spray foam them.
What does Aeroseal propose?
You don’t need access.
They block off all registers and pressurize the space. Then they inject a fog of sealant.
How does this work?
At the leaks the fog forms a rubberized plug.
How do they describe it?
As Fix-a-flat for buildings.
What do some people not like heat pumps?
Because the air coming out of the register is cooler than if you ude natural gas.
What does that cause us to do?
Run the heat pump longer. Leaks make this worse.
Therefore?
Sealing the leaks is vital if you are using a heat pump.
What is their overall point?
It’s not just the efficiency of the heater, but the whole system.
How much can they reude CO2?
Almost 1 ton per household.
How big is this?
Sealing 4 houses is like taking 1 car off the road.
What is their goal?
to do 40 million homes by 2040.
What should be the new way we think about it?
Every time we get a new furnace or air conditioner we should seal the system.
What is building stock?
The measure of square footage of all buildings.
What is expected to happen to Building Stock by 2060?
It is expected to double.
What is this equivalent to?
Building another NYC every month for the next 40 years.
What is the Living Building Challenge?
Looking for building practices that not only don’t contribute negatively to the environment, but contribute positively.
What is an example?
The Bullitt Center in Seattle - one of the most sustainable buildings in the world.
How does the Bullitt center produce energy?
Solar panels on the roof and storing the excess for winter.
How does the Bullitt Center heat?
Geothermal wells.
How do they cool the building?
They run the system in reverse and return the heat to the wells.
Where does the energy come to run the pumps?
The solar panels.
Where does their water come from?
They collect rain water.
How does a Regenerative Elevator work?
They capture the heat generated when an elevator is used and store it as energy.
