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  1. #14
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,293
    The cost of the increased capacity of a Geo system is that more ground loop piping is required of closed loop systems. Piping/digging costs need to be considered. Depending on your electric rates payback time may be long when compared to using AUX strip heat to cover the difference on those really cold days. On the other hand if the digging equipment is already on site the extra looping may not cost that much more.

  2. #15
    Join Date
    Apr 2005
    Posts
    21
    Thanks to everyone for the feedback.

    I got some additional details from one of the contractors and have an additional question.

    Contractor "B" calculated the heating/cooling loads at 57,200/49,000 and is recommending a 5 ton Comfort-Aire system which I understand is manufactured by Climatemaster. Company "D" calculated loads of 61,600/36,100 and is recommending a 3 ton Waterfurnace system.

    I am assuming that "B" is suggesting the 5 ton system to cover the heating loads. However, "D" says that their 3 ton system will cover 96% of the heating load they arrived at. Is it possible that the heating capacity of the 3 ton Waterfurnace equipment would be similar to the heating capacity of a 5 ton Comfort-Aire?

    BTW, 54regcab, the geothermal will be "pump-and-dump".

  3. #16
    Join Date
    Feb 2009
    Location
    Portland OR
    Posts
    1,991
    Quote Originally Posted by batman71 View Post
    Thanks to everyone for the feedback.

    I got some additional details from one of the contractors and have an additional question.

    Contractor "B" calculated the heating/cooling loads at 57,200/49,000 and is recommending a 5 ton Comfort-Aire system which I understand is manufactured by Climatemaster. Company "D" calculated loads of 61,600/36,100 and is recommending a 3 ton Waterfurnace system.

    I am assuming that "B" is suggesting the 5 ton system to cover the heating loads. However, "D" says that their 3 ton system will cover 96% of the heating load they arrived at. Is it possible that the heating capacity of the 3 ton Waterfurnace equipment would be similar to the heating capacity of a 5 ton Comfort-Aire?

    BTW, 54regcab, the geothermal will be "pump-and-dump".
    I will assume the WaterFurnace dealer is quoting a Series 5 unit which shows at a 50 degree EWT a heating capacity of 34,400 BTU's total so if your heat load is 61,600 and they are quoting a 3 ton they are basing on cooling load only(which often is industry standard) however you should be putting in two stage equipment so first stage meets your cooling load and second stage meets your heating loads. I would not put in less than a 5 ton with that heating load and would make sure its two stage or variable capacity equipment to match to cooling load.
    Check out my YouTube channel - http://www.youtube.com/user/skyheating1 We have customer testimonials, product reviews and more!
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  4. #17
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,295
    Quote Originally Posted by SkyHeating View Post

    I will assume the WaterFurnace dealer is quoting a Series 5 unit which shows at a 50 degree EWT a heating capacity of 34,400 BTU's total so if your heat load is 61,600 and they are quoting a 3 ton they are basing on cooling load only(which often is industry standard)

    However you should be putting in two stage equipment so first stage meets your cooling load and second stage meets your heating loads.

    I would not put in less than a 5 ton with that heating load and would make sure its two stage or variable capacity equipment to match to cooling load.
    Batman71's Manual J analysis actually shows heating and cooling loads are nearly equal.

    I am not aware of the water source temperature for central OH.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  5. #18
    Join Date
    Feb 2009
    Location
    Portland OR
    Posts
    1,991
    Quote Originally Posted by dan sw fl View Post
    Batman71's Manual J analysis actually shows heating and cooling loads are nearly equal.

    I am not aware of the water source temperature for central OH.
    Both his load show over a 20% difference between heating and cooling which is over a .75 ton difference on one and a 2 ton difference on the other calculation. Part of it will depend on what water temperatures they expect on the pump and dump system, the 50EWT is what most use for ratings but it could be in the high 30's for heating or in the mid 70's and above for cooling which would once again change the capacity of the unit. There is not nearly enough information to accurately assess the situation but something does not seem right for a 3 ton system that will cover 96% of a 61,600 BTU heating load.
    Check out my YouTube channel - http://www.youtube.com/user/skyheating1 We have customer testimonials, product reviews and more!
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  6. #19
    Join Date
    Apr 2005
    Posts
    21
    My original problem and perhaps the first priority based on what I am hearing here is that I need to get an accurate load calculation. I have figures from three contractors who have quoted the job and am no more sure of the loads than when I started.

    I ran across a company that makes impressive claims about their ability to provide this analysis and have been giving some thought to using their services.

    http://www.load-calculations.com/Contact_Info.html

    Any opinions on this approach or any suggestions on where to turn to get "unbiased" and accurate load calcualtions?

  7. #20
    Join Date
    Jan 2002
    Location
    East Grand Forks, MN
    Posts
    1,373
    Knowing what I do as a designer and installer; I would look for one that does Load-calcs consistently and selects the equipment accordingly. I would then ask for recent install systems installed by them. Matter of fact I highly recommend that you look at a Annual operating cost analysis performed by them! Knowing what I know, anything less than this is not enough to satisfy me!

    Best of luck.

  8. #21
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,295
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  9. #22
    Join Date
    Jun 2010
    Location
    Philadelphia PA
    Posts
    2,190
    To summarize, you have 2 questions not 1
    !. Proper size of equipment for your loads AND
    2. Proper size, design of the geo loop or well you are considering

    #1 we deal with all the time, you have plenty of good advice about the problem of oversizing but #2 is the tricky one. This needs a good contractor with knowledge of local soil conditions etc so that the geo loop is designed properly.

    On a large job they might drill a test well and test the performance so that you will get the right number but on a small/ res job that would not be economical. So make sure you have a performance spec/ scope that has the contractor guarentee the performance. Be ready to hear that person say " we may just peu in extra to make sure we have it covered.
    in today's politiacal climate, I know you might be confused if you heard the truth for a change
    You have got to learn from other people's mistakes! Because God knows you don't live long enough to make them all yourself !!!!!!!!

  10. #23
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,665
    Pump and dump is a huge waste you will use alot of electricity pumping water .if you drill wells you will also get a 30 % tax credit off the wells
    We really need change now

  11. #24
    Join Date
    Feb 2009
    Location
    Portland OR
    Posts
    1,991
    Quote Originally Posted by catmanacman View Post
    Pump and dump is a huge waste you will use alot of electricity pumping water .if you drill wells you will also get a 30 % tax credit off the wells

    Please explain how a water pump on a pump and dump uses more electricity than on a drilled well closed loop.
    If both systems are flowing 3 gallons per minute per ton, why would one be harder to pump?
    Check out my YouTube channel - http://www.youtube.com/user/skyheating1 We have customer testimonials, product reviews and more!
    Like us on FACEBOOK if you like our advice here!

  12. #25
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by SkyHeating View Post

    Please explain how a water pump on a pump and dump uses more electricity than on a drilled well closed loop.
    If both systems are flowing 3 gallons per minute per ton, why would one be harder to pump?

    A well often requires a much higher pressure (head) to maintain the same flow rate due to the lift required as well as the length and size of the pipe.

  13. #26
    Join Date
    Apr 2005
    Posts
    21
    Quote Originally Posted by catmanacman View Post
    Pump and dump is a huge waste you will use alot of electricity pumping water .if you drill wells you will also get a 30 % tax credit off the wells
    Since I have to drill a well for domestic water use anyway, the difference between a "pump-and-dump" and a closed loop system is about $6,000.. I can pump a helluva lot of well water for $6,000!

    With regard to the tax deduction, I've got news for you....I will be taking a 30% tax credit for the well drilled for the open loop system. It's all a matter of interpretation of the tax code. Until our friends in Washington decide to simplify the tax code so that it is clear and understandablke, I will continue to interpret in my favor.

    I do acknowledge that it will cost more to pump 3 GPM from 75 ft. below the surface than it is to pump 3 GPM thru a loop that is essentially horizontal. But, with constant 56 degree water there are some efficiency advantages of the open loop system that will offset some of the extra pumping costs.
    In our area, we are blessed with some very good aquifers. To those who argue that it is not "green" to pump-and-dump, recognize that water dumped back into the adjacent river will find it's way back to the aquifer.

    BTW, I would like to thank all of you who are paying for 30% of my HVAC system through your tax dollars. i really do appreciate that. Of course, I have personally been paying income taxes for 46 continuous years now, starting from age 13.

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