[AC_Hacker]

DonT,

Welcome to the thread!

The Manifesto thread is long, and it has a lot of information that many people have found to be very useful.

Originally Posted by DonT

I’ve been reading this Manifesto for the past several weeks and I’m on page 58, (I’m a slow reader LOL). I’m thinking about putting in a GSHP this summer.

A GSHP is pretty much the most economical form of heating you can have. But it is not like running you are going to run GSHP right into your ordinary house heating system and expecting everything to work just like it did before, only cheaper.

Most forms of heating, such as: wood, coal, gas, electric-resistance, oil, etc. are all High Temperature Heating. Ground Source Heat Pumps are Low Temperature Heating. It may take a while for this idea to sink in, but it is very important to your success.

EcoRenovator 'randen' already had a GSHP system that he had installed heating his home, and he really loved it. So, after he read into the Manifesto, he though he could build one to heat his shop. It was not quite as easy as falling off a log, but he persisted and his GSHP has reduced his shop winter heating cost from about $2400 (oil) to about $600-ish for the winter (GSHP). (randen, if I got the numbers wrong, please weigh in here with corrections)

One of the most important things to bear in mind is that a GSHP will produce hot water at a temperature of 120F max. And you also need to know that if your heating needs can be met with water running less than 120F, your saving will be much greater, the lower the water temperature you require.

There are three big things that can lower the required water temperature:

1. Minimize the heat loss in your heated space by reducing the infiltration (air leakage) to the very minimum.
2. Increase the quality and quantity of insulation significantly above the required code level.
3. Insure that your heat input method, forced-air or water heated radiating panels, are as efficient as possible.

You can't use the methods that worked for heating with wood, coal, gas, oil, etc. because these methods produce much hotter temperatures than a GSHP is capable of... things need to be done in a different way.

Originally Posted by DonT

I have ½ pex tubing hanging 3in down from the subfloor (that was a lot of holes to drill).

What you have is called "suspended tube" and I'm afraid that I have to tell you that it is the very least efficient setup. It will work if you have very high water temps, but it will not work well for GSHP (low temperature heating).

On this EcoRenovator site there is an extensive discussion on building your own radiant floor that can be successfully heated with a GSHP. That discussion starts right HERE.

Originally Posted by DonT

I have a utility room on the ground floor that’s 12ft x 18ft cement slab with ½ pex tubing.

Out of curiosity, did you insulate your 12ft x 18ft slab and it's edges from the ground with about 2 inches of high density blue or pink insulation board?

Originally Posted by DonT

I heat this entire area with a 6000w 10 gallon electric hot water heater, not a boiler. The water temp is set at about 175 deg. For the month of January it cost me $4.95 per day for my heat and hot water (potable).

There is a big difference between 175F and 120F, so you need to realize the differences when working with GSHP systems.

However, this is a pretty interesting setup.

Some questions for you:

• Where is it that you live? what's the nearest town?
• How much do you pay for a kW-h of electricity where you live?
• What is your ZIP CODE?
• Your $4.96 per day was only for the electricity to the heater only and not to anything else like lighting or anything?
• did you have a circulation pump going all the time?

Originally Posted by DonT

I do NOT have AC. I rig up a window AC that kind works.
So, 1st off would I save enough to make the GSHP pay off? It would add AC so that’s why I‘m thinking about doing it

The EcoRenovator named 'randen' did a setup like you are describing and he has loads of hands-on experience. I have a hunch that you'll be hearing from him pretty soon.

I have a new 11350 btu R22 compressor a friend gave me, never used.
A friend has a mini-excavator I can rent for $100, so I can trenching in a ground loop about 8 to 10 feet deep.
My nephew works at a place that make stainless steel tanks and he can make my water tanks for me.

Originally Posted by DonT

What I need to know is how much and what size copper tubing I need to make the Freon to water heat exchanger tanks.

We have had several people here build Heat Pump water heaters from scratch, and they all worked really great. However, none off them were built using a 11350 BTU heat pump. I think that most of them were using compressors about half that size, and they were using copper loops in the tanks that were about 30 feet in length, so you should be able to scale them up pretty easily, like about twice the length, and you would want to increase the diameter a bit. There have been several very clever designs, each with unique features that proved advantageous.

Originally Posted by DonT

For the ground loop, 1st HVAC guy said I need 300 ft per ton ground loop, the 2nd said 500 ft and the 3rd said 800 ft. So somewhere between 300 and 800 ft, big difference. I would like to narrow that down a bit.
So the big questions are the heat exchangers and the ground loop.
This is just the beginning of a lot of questions.
Don

I think that the 300 ft and 500 ft are too short, and I think that the 800 ft might be short also. A lot of it has to do with the year round ground temperature where you live. It also matters what the soil conditions are where you live, sand? clay? wet? dry? a lot of variables.

It will be helpful to know from professional GSHP installers in your area what will work.

But the most important thing you need to know is how much heat does your house require in the worst months? In other words, how much is it losing?

I can calculate it for you if you tell me your price per kW-h, and zip code.

That will tell you how much loop field you will need and how many BTU/h your compressor needs to put out.

Talk you soon,

-AC