My experience with Climatemaster TT30 4-ton

Discussion in 'Geothermal Heat Pump Testimonials' started by kinglerch, Aug 5, 2014.

  1. kinglerch

    kinglerch Member

    I recently had this unit installed in my passive-solar house. My cooling load is bigger than my heating load, due to passive solar gains, so my installer recommended 1000 feet of vertical loop. I have only had it for 2 months and it hasn't been the hottest summer ever, but I thought I'd post what I have seen so far.

    I am not in need of instant cold or heat, so although the TT30 has 2 stages of cool and 2 stages of heat (3 with aux) I set up the ecobee to only use stage 1 for now, which makes the 4-ton unit run roughly as a 3 ton unit. I find the cool air put out by the field to be so cold (around 55deg) that I can feel the dropped temps in the hosue within a half hour.

    As an example, last night the house was 80deg which is fairly hot. The system including the fan had been off the entire day. I turned the unit on at stage 1, and it reached the 75 deg setpoint in 90 minutes. The fan was set to run throughout the night and the unit never kicked on again, as the temps were fairly low outside (around 70deg). At the time the house reached 75deg, the water in temp had risen to 65deg fwiw.

    For me, this is perfect for deciding whether or not to even turn the unit on. Some people are looking for faster cooling (using stage 2 for, example) or needing to come home to a house that is already cool (setting the thermostat to turn on an hour earlier, for example) but with a unit running this quickly, I feel like I can save energy by just turning it on when needed, checking the outside temps and humidity, and make a game-time decision, rather than running it when not needed, or running it just because the program says to.

    The air conditioner it replaced (3 ton) took much longer to get the house temps and humidity down, and a very long time to even feel like it was running. But so far my electric bills have been lower, and the cooling performance much higher. I am not sure if I will see the same performance in the dead of winter, but I am anxious to find out.
     
  2. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I want to make sure that others don't think that a system is underperforming if it has trouble recovering after being left off all day allowing the house to be saturated with heat and humidity.

    Any refrigeration system that is not oversized will be slow to recover.

    Also understand that recovery is impacted by ambient temperatures so if the house is surrounded by 90 degree air and sunshine you will recover more slowly than if it is 70F out.

    Finally air source systems are impacted by ambient temperatures as well, the hotter the air around the unit, the lower the capacity, however a 3 ton surrounded by 70 degree air should give you similar btu's to a 3 ton geo.

    I'm glad you are happy with your geo and hope you stay that way. As you own it longer I hope we see many benchmarks of good performance.
     
  3. kinglerch

    kinglerch Member

    Here are the performance results after I changed to geothermal. If you are not interested in the back story feel free to skip to the next post.

    My results may not be typical (actually, my savings should be more modest than most) since I wasn't seeing high heating bills before geothermal. My house is "passive" solar heated, and additional heat used to be provided by a super-efficient natural gas boiler-style water heater. However, after 4 water heater replacements and poor 20-year old air conditioner performance, I went with a hopefully more reliable 4 ton Climatemaster TT30.

    The house is "passive" solar heated, meaning that while the passive solar properties do work (huge south facing windows, narrow E/W exposure, no N facing windows, R39 envelope, large thermal mass under the house, etc) they only work well in conjunction with the whole house fan, which is not passive. At the very top of the roof peak are the only air returns in the house, where warm air is saved and recirculated through the sand/concrete thermal mass under the house. This saved solar gain is then distributed throughout the house when there is no sun. Because of this thermal mass, the house can never change more than a few degrees in a 24 hour period, and it can never freeze.

    The downside is that running a fan all day every day can be expensive. The house was built with a 450W single-speed blower that can cost almost $40 a month alone. So one added benefit to this geothermal upgrade is the Ecobee controller/Zigbee module. I try to run the fan only when necessary, because even if it does a great job of retaining heat, too many fan hours would be the same energy as turning on the heat. The TT30 also has a variable speed motor, so I can adjust the speed based on what is needed. While the dead of winter needs to save every bit of heat it can by using the blower at high speed, the other seasons can do fine at lower speeds or no fan at all. This brought the $40/month for the blower down to roughly $10-$20, depending on the weather.

    The other big change was eliminating the natural gas bill. The only appliance in the house that used natural gas was the water heater, and despite the efficiency and extremely low gas usage, my gas company charged a monthly delivery fee of $20-$30 regardless of the gas used. This is an extraordinary waste, and moving to geothermal allowed me to turn the gas off and save this fee. Other savings include a more reliable setup, that didn't require a plumber or replacement water heater every few years. And near-silent operation (especially for air conditioning) was an added bonus.

    While my house used to struggle in the summer (due to big thermal mass, unwanted solar gains, poor air conditioner performance) and cost almost nothing to heat, the geothermal unit has an easier time in the summer than the winter due to groundwater temps being so much lower than the thermostat. In summer, stage 1 cooling was not instantaneous but was fine for me. It took just 30 minutes to feel it was cooling, and 90 minutes to reach almost any setpoint. Other benefits to only using stage 1 (other than reduced electricity cost) is that the air conditioning can remove more moisture due to the longer run times, and the desuperheater gets more runtime.

    In the winter I set my differential for heating stage 2 at 2 deg, so it would normally start in stage 2 after setbacks, and then go to stage 1 when within 1 deg of setpoint. I'm not sure if that is optimal, so I may change this to 3 deg before going to stage 2. The problem was that in stage 1 only, with a 20deg day outside and no heat from the sun, it would take many hours to reach setpoint. The thermal mass simply discourages fast temperature changes of any kind. Aux was not necessary and was turned off completely.

    Due to the limited options in the Ecobee system, I added an external temperature sensor that kicks the blower into high speed (heating seasons only, of course) when the house temp is above Ecobee's set point...meaning the house is being heated by the sun. This will distribute and store the heat that would otherwise be lost or confined to only part of the house. There are also more optimizations I will be able to do next year, thanks to Ecobee offering IFTTT integration (if sunny day, turn heat down. if cool outside, turn outside fan on, etc)

    I calculated the savings in KWH over the course of the year because my electric rates fluctuate a lot, and some months were "actual" while others were "estimated". Therefore, comparing the entire year with geo to the average of all 8 previous years without geo seems to be the most accurate. Turning off the gas was a necessary cost savings, because of course electric usage will go up somewhat due to using it for heat now.

    While $ savings is certainly important, there must be more to this than just $. I had to spend $ on *something* to heat/cool. I spent more on geothermal, but the other options were still expensive. I spent $26K on geothermal but after rebates and selling unneeded equipment, the total cost was $16K. If I would have went with a conventional system, I still would have had to spend around $7K. So while it would be nice to "make back" the additional $9K over time, if the system lasts 20+ years without major repair, it is far better than other systems I had that were not lasting long. In addition, my entire utility bill for the year was around $1700 (less than my phone bill) so there's only so much that a new system could possibly save.
     
  4. kinglerch

    kinglerch Member

    The numbers:

    KWH / year before geo: 9048 (prv 8 years) 9744 (last year only)
    KWH / year after geo: 10752

    $ / year before geo: $1677 (includes gas)
    $ / year after geo: $1351

    % savings: around 20%
    years to "make back" extra geo cost: 27 years

    I am pleased (though not ecstatic) with the above numbers. They are modest for a few reasons:

    - Electric cost has risen in my area recently
    - This past year was a cold winter and a humid spring
    - Great performance of the a/c has made me use it more than in the past

    But I believe some upgrades I have added (fan controls, more program controls) should increase the savings next year as well. TBC.
     
    Last edited: Jul 5, 2015
  5. Question, you mentioned using an inefficient 450 watt circulation fan. I'm assuming it is a permanant split capacitor motor (psc). If I were you, I would investigate replacing it with a matched Horse Power ECM (Electronically Commutated Motor)
     
  6. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I believe the dual stage TT30 has a ECM fan standard.

    You are comparing apples and oranges, since your cost of energy has changed, you have use an unknown amount of energy more for cooling.

    If you used 9744 KWH last year, and 10752 KWH this year, your energy usage went up by roughly 1000 KWH, worth about $135, but you cut out the entire gas bill. Not sure if you save any thing by running the unit essentially as a 1 stage unit. You should have gotten a 3 ton max.
     
  7. robertmatas

    robertmatas New Member

    To save energy bills professionals always recommends for servicing in regular intervals. An amtek air conditioner filters, coils, and fins require regular maintenance for the unit to function effectively and efficiently.
     

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