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Now that I think about it, you're right. Adding ducts to the return brings it closer to an open return, which would be the highest volume lowest pressure.

Now that's a good option. Adds volume of air without much increase to the static pressure.

You could add a return fan. Not a great option either.

For HVAC equipment that capacity varies with conditions on the condenser in the case of DX equipment and mixed air conditions on the evaporator and is usually published for various typical conditions...

I'm not sure if the system would hunt more or less with your scheme. You could try it and see. The problem is that during part load the valves and VFD start trying to accomplish the same end. When...

The calc is 144btu/lb lat heat * 2000lb (short ton)/24hr:

144 btu/lb x 2000 lb / 24 hr = 12000 btu/hr

One Ton of Refrigeration removes the amount of heat needed to melt one ton of ice in 24 hours. One Ton of Refrigeration can remove 12,000 B.T.U.'s of heat in one hour.

Ethylene Glycol has somewhat lower viscosity than propylene glycol. If pressure loss is an issue, like in existing piping systems, than Ethylene may work where propylene may not work as well. ...

R-134A is a retrofit refrigerant for R-12 systems and has become the global standard in mobile refrigeration. It is sometimes used in home appliances and is also used in large commercial equipment...

I like that online Psych calculator, Bear.

I agree he is playing with dynamite.

I agree 70% RH is probably wrong (I was just using his numbers to show the process). My experience also tells me...

Also, and I alluded to this already, you can't expect a standard DX unit to handle more than about 25% OA. If the mixed air temperature is above 80 Deg F for an extended period of time, your...

The problem you are having is that the point you are aiming at is the final condition after the air reheats or mixes in the room; the unit doesn't go straight there. It rides the system curve over...

If you have 2.9 tons to throw it and the entering air is 300 cfm at 90/80 100% OA you can achieve about 47/46.57 off your coil. That gives you a DP of 46.2 so with a room air temp of 65 and DP of...

There are problems here. For one, your target RH of 1% puts your dew point at -57 deg F. To drive the air down low enough to get that the air has to be at or below -57 deg F. Now do you mean 41.15...

There are benefits to using indirect water heaters with certain types of boilers. If your boiler is a high efficiency model, then heating domestic water can help give the low return temperatures...

Your best justification is probably just the fact that the more efficient model is the more environmentally favorable choice.

Also look into incentives for choosing the higher efficiency model,...

A life cycle cost comparison can help you estimate how much will ultimately be POTENTIALLY saved over the life of the equipment (potentially because it is an estimate, depending on variables that...

I agree. I also said this in my post. I was just answering his question, "Is there such a thing as plastic ductwork?"

We had excellent contractors. The state inspector said it was one of the best installations he had seen. The panels are some of the more efficient for the money ones that were available at the time.

I looked that up. You are correct. That is usually the case. I did some work in a coal fired plant that was only used for peak, or at least that is what they told me, but what you said makes more...

No. That's exactly what I am against. If you give the money straight into research you are placing it at the top rung of the ladder hoping it will trickle down. What happens usually then is when...

The timing of the rebates and tax breaks was designed to put money back into the economy. Placing it directly into the hands of researchers, while maybe advancing product development a bit faster,...

While this is true that currently solar is subsidized by state and federal governments, it is only a small percentage of what is spent on Fossil fuel subsidies. In 2009 an energy study showed that...

The humidity hasn't improved when the HVAC units were changed for the proper sizes? This should have allowed longer run times and better dehumidification.

All correct.

There are further effects on humans in the airstream, moving air increases the conductivity of the air surrounding the body by replacing it with cooler air, (unless the air is...