>>>We are talking just some quick info for the very early portion of a project. No design will be performed based on it.
I can't tell you how many times I have heard this bad advice and wind up trying to fix something a structural engineer did not understand. Hire an HVAC Engineer
What are you trying to control?
You are going to have to understand what you are trying to accomplish and this information is not included in your post
The crawl space has access to soil moisture that may condense when the wet bulb is high outdoors. Wood structure does not like moisture.
If you have now or will have any piping in the crawl space, you will be glad you heated it depending upon outside conditions. In Fla, no: in NY, yes.
It's also...
You should read ASHRAE on water-source heat pump diversity factors. ASHRAE says that, after night setback, boilers and chillers will have to run at total load conditions, ie, no diversity.
Maintenance free bearings is an oxymoron. Anything that rotates needs maintenance.
I agree that auto oilers are false security as the mechanic will not check the machine for other problems.
The CFM per ton is quite variable depending upon the occupancy of the space it serves. Dry bulb and wet bulb variations will influence the CFM per ton.
Water treatment and a strainer are a good idea.
In my house, we have carbon steel piping from a thermosyphoning water system that's 115 years old and it is fine.
As I frequently point out to clients, the cheapest cooling system is a block of ice and a fan.
What is the best choice for a particular building is frequently not the least expensive
I can't count on my hands the number of times I have had to supply some conventional heat in buildings with air-to-air heat pumps.
Apart from the efficiency, which is drastically reduced at low temperatures, air to air HP are meant for climates where delta T is quite low. If you have -13F, the...