June 05, 2006
Better Building Designs Could Halve Energy For Air Conditioning

MIT researchers have developed ways to design better natural ventilation systems to reduce the need for air conditioning.

Operating commercial buildings consumes a sixth of all the energy used in the Western world. Getting rid of air conditioning could cut that consumption by as much as a third -- but people don't like to work in sweltering heat.

So MIT researchers are making computer-based tools to help architects design commercial buildings that cool occupants with natural breezes.

Buildings can be designed to encourage airflow and maintain temperatures that minimize or eliminate the need for conventional air-conditioning systems. "That approach improves air quality, ensures good ventilation and saves both energy and money," said Professor Leon R. Glicksman, director of MIT's Building Technology Program. Indeed, studies have shown that people generally feel more comfortable in a naturally ventilated building than in an air-conditioned one.

The researchers studied a buildig in Luton Britain which cools using natural ventilation and built a computer model to simulate how the building's air circulates. They were able to find ways to improve the design of natural ventilization designs and think they can cut air conditioning costs in half.

"We found what we initially thought were some strange results when we did the full-scale-building tests," said Glicksman. "But using the computer model, we now understand the physics of it, first of all confirming that it's a real effect and second, why it occurred." Such effects can be corrected by building in automatic control systems that, for example, turn on the vent fans when needed to ensure the continuous flow of fresh air.

Based on these findings, the MIT team is formulating a simple, user-friendly computer tool that will help architects design for natural ventilation. They plan to incorporate the tool into their "Design Advisor," a web site (designadvisor.mit.edu) that lets architects and planners see how building orientation, window technology, and other design choices will affect energy use and occupant comfort.

Natural ventilation does, of course, have its limits. For example, during hot summers in Hong Kong or even Boston, conventional air conditioning would still be needed. But just using natural ventilation during spring and fall in Boston, for example, could save at least half the energy now used for year-round air conditioning, the researchers estimate.

Most popular discussions about energy costs tend to revolve around cars and other vehicles. But boosting efficiency of new building designs seems to me an easier goal to achieve and does not require so many basic breakthroughs in science and technology.

Share |      Randall Parker, 2006 June 05 11:44 PM  Energy Tech


Comments
dbfair said at June 6, 2006 7:14 AM:

One problem with this approach is how it would affect folks who have seasonal allergies. Fresh air is just the wrong thing for them at certain times in the spring and fall.

hamerhokie said at June 6, 2006 8:19 AM:

Air conditioning is not a big issue in the spring or fall. We haven't had to use our AC until Memorial Day, and then only for a few days. No, the big issue with air conditioning in the NE and South is dehumidification, and no natural ventilation will take care of that, unless they pass it through desiccant dehumidifiers first. However, natural ventilation designs may work better in low humidity climates like in Colorado or the high desert regions around Reno.

gmoke said at June 6, 2006 11:29 AM:

"Natural" ventilation can be designed to provide most if not all the HVAC needed for a building. Airflow patterns can assist the passive/active energizing of the day/night cycle, the heat of the sun and the cool of the night. Green building extends even to River Rouge and the green roofs program of Chicago. The London Bed/Zed project is another example that deserves study.

However, good design is always at a premium. To make energy-efficient and ecological systems design part of the criteria for building new or renovating existing structures has been a hard battle for the thirty years that I've observed it and I don't think the inertia of the existing regulations, rules, and codes is going to go away any time soon.

"...boosting efficiency of new building designs seems to me an easier goal to achieve and does not require so many basic breakthroughs in science and technology." True, less new breakthroughs may be necessary for energy-efficient building design but the building trades and the real estate, mortgage, insurance, and commercial institutions that support the existing system are notoriously impervious to change. In addition, it takes maybe a decade to turn over the vehicle fleet but it takes decades more to turn over the building stock. Any solution for buildings has got to be, by definition, long-term and long-term on a scale that our current social/political/economic system consistently fails to consider.

aa2 said at June 6, 2006 1:59 PM:

Gmoke wrote, "Any solution for buildings has got to be, by definition, long-term and long-term on a scale that our current social/political/economic system consistently fails to consider. "

Our current system is based on 4 year plans at most. Anything that can deliver results within 4 years our leaders like because it makes them more likely to be elected. Any long term project that comes to fruition decades from now could actually hurt them, if a rival politician is in power when the project is completed.

People say the problem is ou system isn't democratic enough.. I say the problem is democracy on a wide scale like we practice now. Imo we need to design a meritocracy and trust our leader's long term plans. An example of our short term mentality is having few children. Less costs up front.. but no future in the long run.

Nick said at June 7, 2006 9:45 AM:

"People say the problem is ou system isn't democratic enough"

Democracy is a terrible system, but it's the best we've got. Widespread participation in decision making is the best insurance against bad decisions. A very big part of the current administration's problems is an addiction to secrecy and decision making by a very small group.

Meritocracy? who chooses the meritocrats? The US federal judiciary is arguably a partial model of such a system - look at the fights over appointments.

Can you think of any good examples of such a thing? Singapore runs fairly well, but it's very small.

"An example of our short term mentality is having few children"

Perhaps the best example of a successful non-democracy right now is China. They count their one-child policy as one of their biggest successes.

What we need is more democracy: what we have now is weak democracy, where special interests get backdoor deals, not in the interest of most people (in effect, one group stealing from the rest). What you need is more democracy (meaning more public participation, more transparency in decision making, less secrecy, etc), and less purchasing of candidates. The best solution is probably publicly financed campaigns, which feels like "big government", but would actually get you better, cheaper government.

aa2 said at June 7, 2006 11:44 PM:

...."Meritocracy? who chooses the meritocrats? The US federal judiciary is arguably a partial model of such a system - look at the fights over appointments.".....

Thats the big challenge. Its something that needs to be institutionalized. Like the US military is good at bringing capable generals up. They have to pass increasingly difficult wargames to advance to the next rank. Although with affirmative action they are changing the requirements.

...."Perhaps the best example of a successful non-democracy right now is China. They count their one-child policy as one of their biggest successes."....

China still is at 1.6 children per woman because of the huge number of rural chinese where the government doesn't have much impact. In the longrun however it will be problematic for their civilization unless hopefully we can develop anti-aging therapies.

aa2 said at June 7, 2006 11:52 PM:

..."What we need is more democracy: what we have now is weak democracy, where special interests get backdoor deals, not in the interest of most people (in effect, one group stealing from the rest). What you need is more democracy (meaning more public participation, more transparency in decision making, less secrecy, etc), and less purchasing of candidates."......

That is the general thinking for people who realize there are problems in our system. That what we need is even more democracy. I think however the situation would get worse with more democracy. The problems like short term decision making would get more pronounced if the people had more power.

If you look at the developing world over the last 50 years no democracy went from third world to first. All that did it were right wing dictatorships. For example look at China which is in the process of moving out of third world status.. if the people could vote the poor masses would without doubt vote to take away the wealthy coastal people's money for redistribution. They would also vote for more pension and healthcare money instead of longterm infrastructure spending like the government is doing now.

Nobody said at June 8, 2006 11:30 AM:

aa2 wrote:

"Our current system is based on 4 year plans at most. Anything that can deliver results within 4 years our leaders like because it makes them more likely to be elected."

A method somewhat tangential to the long-term versus short-term leadership idea might make a beneficial change. Think of locust populations. Different populations tend to emerge on different cycles, and specifically on different cycles of prime number of years. I think the most common cycle lengths among locusts are 7, 11 and 13 years, but the specifics really don't matter.

This is an example of pseudorandom sequences occurring in nature.

The point is that survival benefits at least in part because the different populations' flourescence happen so very seldom on the same year, so they don't often compete for food.

What if we had terms of, just say, 3 years for representatives, 7 years for senators, and 5 years for presidents? That would make our government's decisions much less likely to be made by a group of people all seeking re-election in the same year. Might that bring about more sensible government decisions about policy and law?

Just asking.

Rob said at June 8, 2006 3:02 PM:

This article doesn't cover even half of it. I work in the energy management industry as it applies to commercial buildings. There are HUGE savings to be made here in good maintenance alone. For example, I have seen several commercial buildings (we deal with stores mostly) where one of the five HVAC units on the roof has been broken and blowing outside air for months or years. The compressor is still running in summer, still taking up energy, it's just blowing hot air. That costs both in the wasted energy not to cool the air AND in the extra work the other HVAC's have to go through to make up for it. How would the store owner know this was going on? Once mixed up inside the store, the air seems fine.

In the corporate HQ of a store chain, we once found three different HVACs that were improperly installed and controlled such that they each alternated: cool the place down -- opps! too cool! Heat the place up -- opps! too hot! Cool the place down! There were doing this on about a 20 minute cycle each and every day of the year. The people inside had no idea and the building mantenance people were clueless.

We see lights left on 24x7 in parking lots. We see vent fans and water heaters running full blast when not needed. We see freezer doors chronically left cracked open so that the freezer runs hard all of the time. We see airconditioned loading docks where the doors are left open all the time. We even found a store once where they opened the powered doors all the way, then turned them off. The store manager said it was "more inviting" that way - of course, he wasn't paying the A/C bills.

Having seen all of this, I estimate that we could save 10-20 percent of ALL COMMERCIAL ELECTRICITY if we just fixed all of these abuses. Re-architecting our buildings for better efficiency is a great idea, but there is a LOAD of electricity to be saved by boring stuff like putting your lights on automatic controllers and monitoring your HVAC performance.

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