So, I'm trying to decide between the WF 7 series, and the CM Trilogy 40. I have spent the most time looking at the Water Furnace because I'm very impressed with the Aurora Control System, etc. I have really paid no attention to the hot water difference between these systems since we currently have a NG hot water heater. So, do you think I'm making a mistake by paying more attention to the hot water difference? I'm not really sure how to compare the cost of NG hot water to that from a GT system. Oh, I should probably mention that I live in the Dallas area, and we turn down the temperature of our hot water in the summer.

Do you guys see my paragraphs. Because I can't see them in Google Chrome. But I know they are there. If I go into edit, they show up. If I hold my cursor above the subject, there is a pop up that has the paragraphs. I have looked in the Google Chrome settings for a compatability mode, but nothing.

I usually use Apple Safari (6.0.5) on this site, but I'm posting this
with Chrome (Version 29.0.1547.76) on an iMac (OS X 10.8.5) --
and everything seems to be working ok. My Chrome configuration
settings are pretty much the defaults.

And yes, I see your postings with either Safari or Chrome.

Thank you Looby. So you do see paragraphs in my initial post above? If you do, I will stop worrying about that.

Also, I can't seem to get "subscribed" so I get an email when there are replies. Any ideas on that?

Posted By t5800512 on 22 Sep 2013 08:23 PM
So you do see paragraphs in my initial post above?

Yes, I think I see them all -- 18 posts (to date) on the "Vertical Loop Design"
thread, and the first two posts, plus the fourth post, on this thread.

Also, I can't seem to get "subscribed" so I get an email when there are replies.
Any ideas on that?

Sorry, I can't help there. I always turn email notifications off.

...who knows what evil lurks in the minds of Apple & Microsoft?

Looby

In the cooling-dominated Dallas area, 50-75% of your hot water demand should be able to be met by recovering waste heat via a desuperheater and storing it in a dedicated, unfired 50-80 gallon preheat tank. WF series 7 does that.

The question of Trilogy vs Series 7 is so far moot since last I checked, Trilogy has not advanced beyond the press release stage of product development...it is still vaporware - no sign of product specifications, manuals or model numbers on CM's website as of last week.

To compare cost of heating domestic water we'd need to know NG unit cost, electricity unit cost, and energy factor of the existing or proposed NG water heater. If water heating is your sole application of NG, meter charges have to be tossed into the mix, and they alone may blow NG out of consideration.

I'm very much against NG for cooking, especially in the hot humid south. It enjoys an advantage for now for clothes drying, and it is very well suited for outdoor cooking and fueling a standby generator.

Hey Curt, thank you for the reply. That would explain why I have not found that much information on the CM Trilogy. And most of that is from 2012.

So, we use NG for our hot water, cloths dryer, and furnace. The furnace will likely go away when the GT gets installed. I know our electric is 8 cents per kWh but I will have to see if I can find the price we are paying for NG.

I have read that the desuperheater option is rather expensive and requires the addition of an additional tank. I really don't think there is room for another water tank. It will be really tight anyway because the 7 series is wider than our current furnace/air handler.

A buffer tank does not have to be in the same room.
to my knowledge the Tranquility 40 is not yet ready for prime time. Wont be long, but you don't want to be the first to get one (IMHO), let them debug at someone elses house.

Posted By t5800512 on 22 Sep 2013 06:28 PM
So, I'm trying to decide between the WF 7 series, and the CM Trilogy 40. I have spent the most time looking at the Water Furnace because I'm very impressed with the Aurora Control System, etc. I have really paid no attention to the hot water difference between these systems since we currently have a NG hot water heater. So, do you think I'm making a mistake by paying more attention to the hot water difference? I'm not really sure how to compare the cost of NG hot water to that from a GT system. Oh, I should probably mention that I live in the Dallas area, and we turn down the temperature of our hot water in the summer.

I don't see any paragraphs.

See my posting to you, on this subject, in your other thread.  Summary: if you're using IE, you must turn on 'Compatibility Mode.'  Then all works fine.

IE is what I use, and, this setting is what I'm using to type this.  Five paragraphs total in this posting.

Best regards,

Bill

Thank you Bill! I saw that you wrote about IE in my other post. But I could not find a "compatibility mode" setting in Google Chrome. I really don't want to use IE just for this forum.

By the way, I got the email subscription thing working. I put it all in again, and now that works (knock on wood).

Posted By engineer on 22 Sep 2013 08:52 PM
... To compare cost of heating domestic water we'd need to know NG unit cost, electricity unit cost, and energy factor of the existing or proposed NG water heater. If water heating is your sole application of NG, meter charges have to be tossed into the mix, and they alone may blow NG out of consideration.

I'm very much against NG for cooking, especially in the hot humid south. It enjoys an advantage for now for clothes drying, and it is very well suited for outdoor cooking and fueling a standby generator.

Here's some help for the NG subject, all specific to the Dallas area, where NG is plentiful and inexpensive.

For my family of 4 and an automatic dishwasher, with two 50 gal gas-fired HWHs at standard nothing-fancy 67% EF, a gas clothes dryer, a gas cooking range, and NG gas connected outside BBQ grill, we use on average over the last 12 months about 25.2 CCF/mo (which is 737 kWh/mo).  Note there's no furnace NG consumption because we have geo.

For this avg monthly usage we paid over the last 23 months about $33/mo (we use Lone Star Gas).  This is about $1.35/CCF, or about $0.045/kWh.

Over one half of the $33/mo average is a flat $18/mo 'customer service charge' just for the privilege to have NG.

When I installed my WF geo unit, I purchased it with the DSH option, thinking I would be able to take advantage of "free hot water" in the summer, as advertised by WF.  Not knowing hooking up the DSH option directly to a gas-fired HWH was discouraged by WF, I hooked it up, using the WF recommended instructions.

Indeed, using the DSH slightly reduced, not improved, the efficiency of the geo unit.  I learned this because I have the instrumentation (WEL) to show me the numbers.  Since then I, like others, discourage hooking up a DSH option directly to a gas-fired HWH.

To properly take advantage of the DSH option, you need a second 'standby' tank, as Curt states.  But here in the Dallas area, with such inexpensive NG availability, the economics requires a good amount of study.

In my case it would probably cost about $700, maybe more, to have a high quality electric or gas 2nd HWH installed.

I don't know what portion of my gas bill is for hot water heating.  I've looked at NG consumption transducers that easily hook up to my WEL unit, but, the transducers are expensive, and it didn't appear to be worth the expense.

Let's assume half of the NG bill is solely for hot water heating.  That's $9/mo (half of $18).  Let's further assume the DSH can supply free hot water overall about 80% of the year.  That's $9 * 80% * 12 = $108 / yr savings.  That's about an 8 year Break Even period on a 10 year asset (HWH).  Not something that I've been willing to do.

If I had it to do over again, noting again I have NG fired HWHs, I would have skipped purchasing the geo unit with the DSH option, and saved the money on the purchase price.

Scott, I'd carefully put 'pencil to the numbers' in your case.  If you have up to moderate HW heating needs, then the economics of purchasing the DSH option along with a 2nd staging tank may not be worth it, due to such low NG rates.

I know it's not worth it to direct connect the DSH to a NG-fired HWH, as will say those here who are much smarter than me.

Hope this helps.

Best regards,

Bill

P.S.: I don't know why Curt is opposed to NG for cooking purposes.  We like it just fine.

Best I can tell, it is just the first post of a thread that loosed the paragraphs and white spaces. So, I will try to keep them short from here on out.

Posted By t5800512 on 22 Sep 2013 06:28 PM

... I live in the Dallas area, and we turn down the temperature of our hot water in the summer.

In fact, we use very little HW in the Summer.

My WEL system shows that incoming cold water is at about 77°F right now, and hits its annual warmest high at about 79° in the month of Aug.

See: http://www.welserver.com/cgi-bin/pl...onthly.png .

Best regards,

Bill

Hey Bill, thank you for the very well thought out responses. You have confirmed what I was thinking. Not to mention that I don't know where I would put another water tank, even if I moved it to a different location.

Scott

As said before the CM 40 is not available from what I have heard either and the 7 Series has been out over a year and I have put in a lot of them with no issues. If you are worried about WaterHeating look at the WaterFurnace NSW018 or NSW025 that can do 100% of your water load but if you have a NG water heating system you probably won't see a payback on the NSW or desuperheater but somebody in your area that knows your rates would be able to better help you with that answer.

Best I can tell, the only rebate is the 30 percent Federal tax credit. But I'm not complaining.

I will likely just stay with my totally low tech NG water heater. It does not sound like the other options would pay back when compared to the NG. Now if I had electric hot water, I would be all over the geo water heater option.