Systems compared — A conventional system brings in the maximum amount of outside air, whether needed or not. No allowances are made for crowd size. The cooling unit functions as an air handler even if CO2 levels are extremely low.  	
  
  In a split system, the cooling unit only recirculates air inside the building. Human respirations increase the buildings CO2 levels and trigger the CO2 sensor to turn on the outside air intake system. So this ventilation system only brings fresh air into the building as needed, depending on crowd size. This dramatically lessens energy consumption and cost.

Systems compared — A conventional system brings in the maximum amount of outside air, whether needed or not. No allowances are made for crowd size. The cooling unit functions as an air handler even if CO2 levels are extremely low.

In a split system, the cooling unit only recirculates air inside the building. Human respirations increase the buildings CO2 levels and trigger the CO2 sensor to turn on the outside air intake system. So this ventilation system only brings fresh air into the building as needed, depending on crowd size. This dramatically lessens energy consumption and cost.


In With The New; Out With The Old

Lots of Pollutants

Within any building, many things affect air quality. Those things include carpeting, paint, paneling, furnishings, etc. Each or everyone can emit gases into the air that are bad for us. Organic materials within a building can harbor their own kind of bad stuff, such as mold, mites, bacteria, viruses, insects and even vermin.

Attempting to eliminate this bad stuff with chemicals can often be worse than the infestation. Then too, interior air can be further soiled by mixing with exterior air that enters a structure with its own pollutants.

So just what is the solution?

The ideal solution is to keep those pollutants out that can be kept out and still provide a comfortable, safe building. Others can be swept or filtered out, or the unclean interior air can be diluted with fresh exterior air, if it is cleaner. But what is the best, most energy efficient and economical way to do this?

Over the years, official bodies responsible for establishing codes governing air quality made a concentrated effort to write a one-size-fits-all method or code. Thus, they determined: we should sweep or dilute the air within a structure by bringing in 15 cubic foot a minute (cfm) of outside air per person. That brought-in air will — obviously — displace unclean air that will be forced out.

So, one might conclude, dilution, by itself, can create healthier indoor air.

Problems

Unfortunately, there are some real problems with this approach. Firstly, the outside air may not be cleaner than the inside air. We often have smog alerts, ozone alerts and bad air quality. Consequently, the assumption that outside air is cleaner simply because it’s outside should not be made. It’s not unusual for people to be advised to stay inside on bad air days. This means the outside air is expected to be dirtier than the inside air. And, if the air inside a building is cleaner than the outside air, the air exchange becomes self-defeating, solving nothing and creating an unnecessary expense.

Secondly, if there is a lot of bad gassing within a structure, 15 cfm per person may amount to only an insignificant fraction of what is really needed.

A solution

But in addition to the one-size-fits-all solution that simply pumps in 15 cfm of exterior air per person and pumps out 15 cfm of interior air per person, the air quality code does allow a few other plans. One such plan measures the carbon dioxide buildup within a structure and begins bringing in fresh air only when the carbon dioxide reaches a certain point. The idea is that carbon dioxide can be measured relatively easily and is a good indicator of other gases increasing at the same time. This plan works especially well in Monolithic Domes.

The Monolithic Dome is one of the cleanest structures that can be built. Unlike most conventional buildings, Monolithic Domes do not use wood — a harbinger of bacteria, viruses, molds and more. Concrete, the main ingredient used in Monolithic Dome construction, probably is the cleanest and safest building material available. So, by using nontoxic paints and floor coverings and avoiding things that produce serious amounts of pollutants, the dome’s interior air remains acceptably clean.

Obviously, when large numbers of people enter a Monolithic Dome, the quality of its interior air changes, since people breathe in oxygen and give off carbon dioxide and other toxins.

Conclusion:

The most practical and economic plan for maintaining a Monolithic Dome’s interior air quality includes a means for measuring carbon dioxide buildup and bringing in fresh air only when and where it’s needed, instead of continually pumping fresh air throughout the structure.

Maintaining a Monolithic Dome’s interior air quality as well as its energy efficiency is not only possible but vital. If the indoor air needs to be swept out, that should be done. On the other hand, if the exterior air is not better than the interior air, simply sweeping the dome with outside air will do nothing but create costs.

For example, if it’s 110 degrees outside but only 75 degrees inside, sweeping the inside air with the outside air will either significantly warm the inside or necessitate air conditioning. This costs money. Of course, if it’s necessary, it should be done. Otherwise the money and the energy required for air conditioning should be saved. When we save energy, we save more than its cost. We save our environment from pollutants created when we burn coal to produce energy. So, it’s a balancing act.

That balancing act for Monolithic Domes

Large domes have a lot of space inside, a lot of volume. That volume helps maintain interior air quality. A small volume of inside air will get dirtier quicker than a large volume.

Let’s say we have a large Monolithic Dome, such as an auditorium. Its air quality control system measures carbon dioxide buildup and triggers the flow of fresh air at the rate of 15 cfm per person only when the carbon dioxide reaches a certain level. Because of the dome’s large interior volume, it may take a long time for that to happen. Possibly, the carbon dioxide level will never reach the point at which fresh air is needed. It’s also possible that the air dilution could be postponed to a time when the outside air is cooler, necessitating less air conditioning.

Thermal Storage

Each year, many structures in America are cooled utilizing water or ice for thermal storage. A Monolithic Dome utilizes itself — its own structure — as a thermal storage. The concrete for a moderate-size gymnasium or church will weigh about 900 tons or 1.8 million pounds. The amount of heat to raise or cool one pound of concrete is about two-tenths of a BTU per pound of concrete per degree Fahrenheit. For five degrees, one pound of concrete absorbs one BTU.

Human beings like to be kept within a certain temperature range, usually 70 to 75 degrees Fahrenheit. This five degree temperature differential for a structure that weighs 1.8 million pounds will equal 1.8 million BTUs of heat. In other words, the Monolithic Dome is a thermal storage that stores 1.8 million BTUs for each five degree temperature change.

We design Monolithic Domes to take advantage of this, particularly large domes that will be occupied by large numbers of people for relatively short time periods.

Here’s an Example:

Before an event we can cool a dome to the low end of our comfort zone: 70 degrees. During the event, the dome will absorb the 1.8 million BTUs it naturally absorbs. After the event, the dome can be cooled again.

The 1.8 million BTUs are equivalent to 150 ton-hours of air conditioning. If the event is three hours long, the thermal storage can replace a 50-ton, air conditioning unit.

Such a procedure means a significant decrease in the size of the cooling system needed for that structure. In fact, in climates where night air is cool enough, it may be possible to eliminate air conditioning all together.

My Idaho Home

It never needed artificial cooling. Naturally cool air cooled it at night. Our dome home was then closed up during the day, when it absorbed the heat from the inside and the sunshine coming through the windows. Interior temperatures would rise five degrees during the day and cool down again during the night. Although the dome was closed during the day, its large volume of air maintained ideal air quality. These same principles apply to the design of much larger Monolithic Domes.

What This Means:

The system used to pump fresh air into a Monolithic Dome should not be connected to its air conditioning. Fresh air should be brought in when the carbon dioxide sensor says it’s needed. The cooling system should be used only when needed. And since Monolithic Domes utilize their own structural thermal mass, they require much smaller, cost-saving and energy-saving cooling units.