Heat pumps are all the rage these days, and for good reason, but it turns out that ancient Persians had ways of making and storing ice, long before refrigeration existed. Today, engineers are taking from that ancient knowledge to design homes that cool without the need for electricity. And it could be the future of building design.
It didn’t look like this when we moved in. It had insulation, but just a few inches of it, so being in Texas and my office where I usually shoot my videos is on the 2nd floor, it would get unbearable real quick.
So a while back we got the attic re-done with new insulation and a radiant barrier on the roof. And it helped… some. We still eventually had to replace our HVAC system to something that could pump out a lot more …heat like this unit is doing right now. That’s a lot of heat.
So even with all that attic work and – oh, I also replaced all my windows with new energy efficient bad boys, and the new, more efficient HVAC system, it still takes a lot of electricity just to keep this house comfortable.
That’s kind-of amazing when you think about it. People have been living in houses and dwellings for thousands of years, and electricity is only 100 years old. How did they make all this happen? And what could we learn from it?
So I recently traveled to Ireland, home of green fields, cloudy skies, pasty skin, and very, very old buildings.
From neolithic tombs called Dolmen, like this one named Poulnabrone that dates back over 6,000 years, to tower houses that would display the wealth and opulence of Celtic chieftains, everywhere you look are reminders that as long as there have been humans, we have been building dwellings.
And it’s only in the last 100 or so years that we have used electricity to heat and cool these buildings.
So there’s only two options, one, that humans were miserably uncomfortable for thousands of years up until very, very recently in our history, or they found ways to build their homes so they could be comfortable without electricity.
I don’t think the first one is true, yes, we have a lot more comforts now than we used to, but I think the human desire for comfort probably existed before electricity.
So how did they do it? How did they build for comfort without using any electrical or mechanical means? And in a day and age when temperatures are higher than ever, and our grids are stressed to the breaking point, what can we learn from that?
I spent the intro to this video primarily talking about keeping heat out of my house, that’s because it’s summer in Texas right now but keeping the cold out is just as important, as we found out last February.
That was when we had that epic cold snap that pushed the Texas power grid past the breaking point, which led to blackouts that lasted for days for some people, and at least 246 people died.
By the way, the worst power outage in U.S. history was the Northeast Blackout in 1965. It prompted new, federal regulations to ensure that the nation’s power grid would be reliable.
ERCOT stands for the Electric Reliability Council of Texas. Not to be confused with EPCOT, a totally different type of beast.
ERCOT was formed in 1970, and it manages the Texas power grid beyond the Federal Energy Regulatory Commission’s jurisdiction.
Not all of Texas is under ERCOT’s management. There are some parts that belong to the national grid. But for the most part, if you live in Texas, you live with ERCOT’s grid.
And as we enter the second summer after that incident, we’re still dealing with the threat of rolling blackouts, shutdowns, and failures. Why? Because the equipment is old.
And there’s a bunch of politics and money exchanging hands that’s too much to get into for this one video.
But Texas isn’t alone when it comes to concerns about the power grid, that’s because the use of electricity across the country is on the rise.
The more we turn away from fossil fuels and toward electricity, the more power grids will be pushed to the limit.
One thing a lot of people are talking about right now is a heat pump, which moves heat from a cool space to a warm space.
The pump makes the cool space cooler and the warm space warmer. Basically, it transfers heat instead of generating it.
The Netherlands government is on board, banning fossil fuel heating by 2026 and mandating the use of hybrid heat pumps.
The government said this could lead to a savings average of 60 percent on natural gas consumption.
No, they weren’t miserable. They were clever. And they devised some really simple ways to live comfortably. And these are pretty cool.
Let’s start with wind catchers.
The city of Yazd in central Iran has the most wind catchers in the world.
The city also includes other heat-beating structures, like an underground refrigeration structure called yakhchāl and an underground irrigation system called qanats.
Wind catchers are often rectangular but can be circular, octagonal, square, or other shapes.
Here’s how they work: Two, main forces drive air through and down into the housing structure. These are the incoming wind and the change in air’s buoyancy, depending on the temperature.
The wind catcher catches the air, funnels it down to the dwelling below, and deposits any debris or sand at the tower’s foot.
Air then flows throughout the structure’s interior, sometimes over subterranean water pools for further cooling.
Warmed air eventually rises and leaves the structure through another tower or opening, aided by pressure in the structure.
According to researchers, using wind to cool structures goes back all the way to Egypt about 3,300 years ago.
There, the structures had thick walls, few windows that faced the Sun, and openings to let the wind in and out.
In desert regions of North America, Native Americans would either live in caves or build homes with thick adobe walls against the sides of mountains to help stay cool.
On the flip side, the Inuit people used to construct igloos to stay warm in the Arctic regions.
Igloos stay warm because their snow walls are good insulators that help keep in body heat and heat generated by oil lamps that the Inuit use for cooking and socializing.
Traditional igloos were made out of snow since solid ice doesn’t retain heat as well as compressed snow.
The Inuit would also keep on their fur-lined clothes while inside the igloo during the day and would sleep at night wrapped in heavy furs to stay warm.
So, for thousands of years, people figured out how to stay cool and warm without the need for electricity.
I know, I know, electricity is great and all, but what if you could slash your home’s use of it by up to 90 percent and still remain comfortable?
That’s the idea behind passive housing.
Now, while the word housing is in the phrase, this concept can apply to a variety of structures like apartment blocks, industrial facilities, retail stores, schools, etc.
In fact, passive housing is great for larger structures because they have more efficient geometries.
As the structure gets bigger, the ratio of its surface area to its volume decreases. And this increases its efficiency.
There are two different and independent passive house certifications and standards. The German-based Passivehaus Institut administers one, and the U.S.-based Passive House Institute US administers the other.
Despite the similar names, they are not affiliated with one another.
Each group offers basic certifications, net-zero options, and a retrofit certification.
Both also have standards that are grounded in building science and physics, require practitioners to use a common suite of design principles to achieve targets, and focus on three performance metrics.
Those metrics are building airtightness, thermal energy demand, and total energy demand.
The main difference between the two standards comes down to performance targets based on the climate of a project’s site.
For example, PHI has the same cooling and heating load/demand criteria for all climates around the world, except for a dehumidification demand that is dependent on climate.
But PHIUS has “climate-specific” targets that are tailored to their locales.
There are five fundamental design principles behind passive housing, including:
- Airtight construction
- Continuous insulation
- Filtered fresh air with heat recovery
- High-performance doors and windows
- Thermal bridge-free design
These principles are joined by other principles:
- Building orientation
- Daylighting and solar gain
- Efficient water heating and distribution
- Moisture management
- Passive housing offers several benefits.
Saving electricity isn’t the only benefit to all this, a lot of it is about filtered airflow.
They do this through balanced ventilation systems, which don’t just keep the house cool, it also prevents mold and mildew from arising.
Passive housing structures are also quiet, have no dust, keep bugs outside, eliminate moisture and odors, are durable, and are more affordable in the long run.
Here in Dallas, the first passive house went on the market in 2018.
It was a 300-square-meter (3,230 square feet) home with two levels.
It also had a water harvesting system and 4.8 kilometers (three miles) of buried tubes in its yard that acted as an irrigation soaker system with no roll-off.
The house was pre-wired for solar panels, and it made use of smart technology to control household functions.
While there are plenty of advantages to passive housing, there are some disadvantages, too.
For one, the upfront cost can be 10 to 30 percent higher than traditional construction. Ideally, you’d be able to make that up with all the savings in electrical bills over a few years.
Passive house construction can also be challenging in places with hot summers or cold winters.
In fact, it may be necessary to have backup cooling and heating systems. Builders may also need lots of insulation to stay below the limit of 15 kWh a year.
Window areas may be limited because of the required energy performance standards. Also, those windows used must have a Low-E coating and triple glazing.
Another thing to consider is if a passive house will retain its value. Local property values and politics need to be thought about.
Some locations are more open to houses built to help protect the environment, while other locations may be indifferent or show contempt for these types of houses.
To recap, passive housing includes the following elements:
- Proper insulation
- No air leakages
- No thermal bridges
- Proper windows
- Proper shading and orientation
- Uses heat recovery ventilation
Biomimicry is another way we can design structures that are naturally cool or warm. Take Eastgate Centre in Harare, Zimbabwe, for example.
Designed by architect Mick Pearce, the country’s largest office and shopping complex has no conventional air-conditioning or heating.
But it stays a consistent temperature year-round. That’s because its design was inspired by termite mounds.
Termite mounds have tiny holes in them that allow air to be pulled through freely. It basically operates like a lung that inhales and exhales throughout the day as the temperatures rise and fall.
The Eastgate Centre is similar. Outside air is drawn in via low-powered fans and is cooled or warmed by the building’s mass, depending on the temperature of either the concrete or the air.
Its air is then vented through the building’s floors and offices before leaving through chimneys at the top.
Pearce included jagged stone on the building’s facade that is meant to emulate cactus prickles.
Since pointy surfaces have a greater surface area than flat ones, they absorb less heat. They also bleed off heat more easily, helping keep Eastgate Center cooler.
Because of all this, the building stays between 28 degrees Celsius (82 degrees Fahreinheit) during the day and 14 degrees Celsius (57 degrees Fahreinheit) at night.
And it does so using less than 35 percent of the energy of similar buildings in the country.
It literally doesn’t have an air conditioning system. And because of that, the building’s owners have saved at least $3.5 million and the tenants’ rents are 20 percent lower than other buildings in the area.
Another building taking its cue from nature to help stay naturally cool or warm is the “Gherkin” in London.
This was designed by Norman Foster based on sea anemones and sponges.
The building’s cylindrical shape allows wind to flow quickly around it and drive wind through the structure’s center to help keep it cool.
Then you have the Spring Mountains Visitor Gateway in the Humboldt-Toiyabe National Forest Headquarters in Nevada.
The structure uses several biomimetic elements in its design, like highly efficient radiant heating tubes that move cool and warm liquid to different areas in the building.
This is similar to the ears of a Black-tailed Jackrabbit.
Jackrabbits use their huge ears to pump blood through to help cool them off, this works on the same principle.
So, I get into this because I think it’s really cool, you know, using nature to find simple solutions.
But it’s also really important. According to the North American Electric Reliability Corporation, we might be running into some problems pretty soon.
They released their Summer Reliability Assessment for 2022 in May, and it warned of a high risk of failure throughout the midwest, while Texas and the western US is at an “elevate risk”
According to NERC director John Moura, “It’s a sobering report, “It’s clear the risks are spreading … and the pace of our grid transformation is a bit out of sync with the underlying realities and the physics of the system.”
It’s a warning we should pay some attention to. Because the problem’s only going to get worse.
Humans lived for thousands of years without electricity by being clever. Let’s face it, we’ve gotten lazy over the last 100 years.
But we seem to be finding our way back to clever. Heat pumps are all the rage now, and they’re pretty clever.
It’ll be interesting to see how far our cleverness can take us.