Freezers require an underfloor heating system as explained above or the frost will heave the concrete. Either a radiant system (typically operates at 60F) or an underslab ventilation system, either forced or gravity.
If you are using standard AC units forget the ACH calculation and base the CFM on the load calc. The ACH calc has nothing to due with the heat gain into and within the room.
I've designed ammonia refrigeration systems that have valve tags...one thought I've been kicking around is the use of RFID tags to store the information on the valve itself in addition to the valve number. Anyone doing this?
If you're looking at geothermal for a residential application consider using a direct exchange geothermal system. Rather than pumping water for the heat source/sink, the refrigerant is coupled to the ground.
Search Direct Geothermal Exchange for details.
Why? Energy savings. Power is proportional to cube of speed. A 20% reduction in speed = +/- 50% reduction in power.
An arguement can be made that if you run the pump back on the curve you'll be running at a lower BHP...so the above statement is rough.
BigInch - system pressure will remain constant but flow will vary...the key to making a VSD work is to get a pump with a high rise to shutoff. Granted the drive will probably only operate from 80%-100% capacity. See attached...