best geothermal unit mfg

george_42

I will be building my home in the spring and will be heating and cooling with closed loop geothermal. The design load is 3.5 ton . I will be doing water to air and using unit to also supplement dhw with electric water heater. I would like recommendations on best manufacturer and whether I should use a 2 speed compressor or a variable speed . Any comments appreciated , George

SWEI

Variable speed (aka inverter drive) on compressors is a HUGE game changer for the industry. If the budget allows, I would strongly recommend it.

How are your annual cooling and heating loads relative to each other? What kind of ground temps in the winter?

george_42

heating and cooling loads are about equal in central pa with ground temps about 50

george_42

any preference as to manufacturer

Harvey Ramer

I am in central PA as well. Unless you oversize your loop field, or have excellent soil conductivity, you can expect approximately 40°F water temps from the ground loop in the winter.

The heat loads around here are typically 50% to 75% higher than the cooling loads.

You definitely want a multistage unit. There are also variable speed pumping options available that help raise your COP. You can in some cases, size the unit so it meets the heating load without backup. When you do that, you have to pay close attention to your latent cooling load and the sensible heat ratio performance of the first stage cooling in the GEO unit you choose. Otherwise you end up with high humidity levels in the house during the summer.

I would be more concerned with picking a GEO unit that is the best match for your needs and application, then I would be with the brand.

george_42

I will be drilling deep wells for geo source so I think water temps should be near 50. loop down and back and filled with bentonite

Harvey Ramer

When you say deep wells, how deep are you talking? You are limited in depth by the type of piping that you use. If you go to deep, the water pressure will blow the pipe apart.

george_42

I have a well driller that does this all the time , he will drill the needed wells and stub the pipes inside the house for the Geo contractor ( a friend of mine,I am a plumber but don`t do hvac )

EBEBRATT-Ed

haven't done any in a while but Water Furnace seamed to be a quality unit.

Harvey Ramer

Do yourself a favor and make sure they bring all the individual loops to the inside of the house. Then you can build your own manifold and get the flows to the different loops balanced properly.

I wouldn't let anybody drill wells without seeing the loop field design and calculations. You are building a heat exchanger in the ground and there are a lot of variables that need to be figured out.

There are a lot of well drillers who do geothermal. There are only a few that actually understand the process and know how to properly design and implement a loop field.

All i'm saying is, this is a 1 shot deal! Make sure your I's are dotted and your t's are crossed.

george_42

thanks for all your input, it gives me a better view of the approach to take , george