Technical FAQ: HVAC

What happens with excess static pressure?

It is taken care of. The system balances the airflow in such a way that no less than X% of dampers are open at the same time. Preliminary modeling shows that X should be no more than 30-40, otherwise there will be loss of quality control. This means that the ductwork should be capable of supporting proper airflow even with only 30-40% dampers open. This is unavoidable.

Does the system need bypass dampers?

Short answer: no.

Long answer: the system takes care of excess static pressure in a different way.

Longer answer: here.

Are $10 dampers better than $200 ones?

The damper in question is here.

Short answer: yes and no.

Long answer: of course, they are better from cost efficiency standpoint. However, "what you get is what you paid for", to some extent (actually, "up to what you paid for"). The register based dampers are not as good as (allegedly) precision engineered airflow dampers, however, good registers may do a better job than "entry level" dampers. Another disadvantage is that the registers are almost guaranteed to create an air velocity loss because they are not placed at strategic locations, as the dampers are. This leads to lesser efficiency.

However, exactly as there are people who can afford Huyndai and can't afford BMW, there are people who can afford $10 dampers and can't afford $200 ones. The poor people suffer from heat and cold exactly the same way as the rich. If you can't afford $200, $10 will definitely make your life easier.

What about high temperature differential?

The complete question is "What about high temperature differential across the indoor coil due to low airflow"?

With single stage A/C, there is a limited ability to protect the compressor from high temperature differential at least by shutting off the compressor while letting the fan run. This is a theoretical answer, from the practical standpoint it is yet to be seen how high the temperature difference will get when the airflow is restricted in a way it is being done by this system.

The best answer to this question is: use multistage compressor coupled with variable speed fan (see Homeowner's FAQs). This way, fine grained control is possible.