Bill,

Thanks for posting the links for the welserver. I read about the system on the providers website. This system is not only what I was "kind of" thinking about, it's much more sophisticated then anything imagined on the market. Other then pumping the data out of an RS232 port to massage in a local PC, I wish they offered a HTML server SW to run at home. Living in the sticks, the only internet option for me is G3 (cellular). Not very convenient or reliable... OK. can't help myself. Gotta log off this forum and get back to the welserver website. The coolness factor is way up there!

Thanks!
john

For purposes of calculating full hot water cost I figure 72 Watts for my DSH pump. I'm sure that during cooling season I get a few of those Watts back in the form of slightly reduced compressor head pressure and amps, but I haven't been able to measure that difference so far. My clamp ampmeter isn't the best.

John, I believe there are a few WEL users who are indeed running on their local computer (logging the data to it, etc.).  I believe the fundamental required is that you have an Ethernet network.  I.e., the WEL, the local PC doing the data logging, etc., are connected via a network switch.  And it may require some pretty sophisticated computer skills to do what is essentially setting up a server.

It's been a while, though, since I last heard of someone doing this.  I'd contact the WEL developer, either directly via email, or via his forum ( http://www.ourcoolhouse.com/go/forum/post ).

BTW, in another posting here on this forum, I believe WEL user 0144 ( http://welserver.com/WEL0144/ ) is a frequent poster at this forum here too.

I'm getting ready to change my WEL setup to reflect the performance of a solar PV system that is under construction as I 'speak.'

Best regards,

Bill

Engineer - My unit has the Grundfos also. 72 watts compared to what the water heater resistive coils would use is not enough for me to worry about.
Thanks!

Bill - The welserver is a perfect fit for what I'm looking for. In my previous life (70's to early 2000's) I was a network systems engineer so it's right up my "old" alley. No problem getting data from RS232 format onto a disk, then setup my own app server to display collected data. It wouldn't be as sophisticated and professional as displayed on ourcoolhouse.com, but the info would be there. This is exciting because I hope to show clients how the Envision performs in my HERS 49 SIP house. I know that the house is VERY energy efficient, but prospective clients are typically juuuusst a little skeptical... Can't blame them and it's my job to prove the claims I make.

You all give great info! Wish I found this forum sooner.
Thanks,
John

Its not quite as simple as that - the DSH runs many times as long as water heater elements do. In a heavy month of summer cooling the dsh pump uses 20+kwh, a minor, but not negligible addition to my kwh use

Curt, how do you get "20+ kWh?"

If a 72 watt pump runs 24 hours non-stop, that's 1.7 kWh /day.  You must be refering to total energy consumption for the Summer period. 

Best regards,

Bill

Oops - incomplete post. Meant to write that a heavy summer month requires ~300 hours of cooling operation, during which the DSH pump runs along with the compressor. That works out to 21.6 kwh, assuming my guess of 72 watts is correct.

Thanks Bill and Engineer. I'm not worried so much about the pennies but want a better overall understanding.

The WELSERVER is an "Excellent" concept and in my mind, a fantastic value. On one particular page however, there is something puzzling. see http://welserver.com/WEL0043 - Look at Zone 4: The blower is off, the EAT is 75 and the LAT is 97... Something appears amiss. Actually something is amiss in several areas..

Side note: I've reviewed the 1 wire protocol, theory of operation and specs on some various Maxim IC devices. I see an alternative way to do this with much increased functionality. Looks like 28 years as a network systems engineer (previous life) has unexpectedly opened up a whole new world. Stay tuned... Will open a more appropriate thread later.

I'm "WEL0043."  I use the WEL's sample and hold function considerably, such that operational measurements are only made when the units are running.  Otherwise, the charts would be constantly returning to ambient conditions, preventing long term viewing to spot developing problems.  And viewers of the system diagram would constantly have to look to see if the units are running to make sense of the numbers.

Will be happy to contribute detail in another thread, so as to not get this one off track.

Best regards,

Bill

I have Data loggers for averything and I have the same T27 4 Ton and with two watr tanks. It makes so much sense and I'll give you another idea. I use to have two standard electric 50 gallon water heaters. I used 11 KWH for DHW on a day without the GTHP being on. On a 40 degree day out my KWH for DHW goes down to about 3KWH. Since my GTHP is off quite a bit in the spring/fall I went a step further in savings. I installed as my primary DHW tank a GE Heat pump hot water heater. Now my costs for DHW are near nothing all the time.

You really need to do this stuff right the first time and save all you can especially with the tax credits. There was a fed tax credit on the GE DHW heat pump.

John

I've read a few times now that it is possible under certain circumstances that a desuper heater would actually take heat from the water (it is supposed to be heating) and transfer to the refrigerant, this then would actually increasing your Domestic Hot Water cost rather than decreasing it. 

I'm reading the control sequence on for my Climate Master 3 ton dual stage unit "TTV" model and seeing that the controls won't start the desuperheater circulation pump until the refrigerant gas reaches 140 deg F.  Once the pump is started it runs until the unit turns off(thermostat is satisfied in the space) or the incoming water reaches 120 deg F.  It seems like this control setup would always ensure that there is a positive temperature difference between the refrigerant and the water (refrigerant temperature being hotter).

If the above is true... then it seems it would be possible to save some (domestic hot water heating) energy by connecting a desuperheater to a single hot water heater.   Assuming it is a dual element type where the lower element is turned down to 90 or 100 degrees and the desuper heater draws from  and discharges at or near the bottom of the single hot water tank. 

If the unit came with the desuperheater and circ pump (like mine) and you already have one, dual element electric water heater... then to implement a plan like this would just cost me the interconnecting piping. 

Again assuming all the above is true... one side effect of desuper heater system with a single tank-bottom element turned down- is that whenever the unit/desuperheater is not running alot (ie. the spring, fall, AND summer - being located in West Michigan), I will have 30 to 50% less hot water available for use at any given time (compared to now with both elements set at 120 and no desuperheater connected). 

Any other side effects, corrections, or thoughts.

Thank you..

I'm not an expert. I'm also not sure what those circumstances would be with our Water Furnace (WF) Envision units. I read in WF documentation that the DSH should not turn on unless conditions are right for generating hot water. When observing the unit running in cooling mode and heating mode (so far this season), our DSH output line is always hotter than the input line. At the time we purchased our units in April 2009, WF recommended a lower thermostat temperature of 100 degrees (I believe) with a single tank setup.

I believe you are correct with having some reduced hot water capacity during shoulder months, but that doesn't necessarily mean that you will notice it. That would depend on household peak hot water use (within a short time frame), the amount of "fully" heated water already at the top of the tank, how quickly the upper element can heat the 100 degree water (from the bottom of the tank) to 120-130 degrees. Maybe one of the experts here would be kind enough to give us the formula for calculating this time given a heating element power (like 4500 watts) and a 30 degree rise in temp (or I could just Google it.)

A DSH with a single tank setup can keep your water heater at temperature during periods when you have little hot water usage. With a buffer tank, your finishing tank needs to keep the hot water at temperature on it's own.

If you need more hot water in the shoulder months, you could increase the lower thermostat setting on the water heater. I would mark a date on calendar as a reminder to change the setting back again per manufacturers instructions.

When it's time to replace your tank, and if you still want one tank, you could get a larger tank, as we did. This allows for a larger amount of hot water at the top of the tank and a larger amount of cooler water at the bottom of the tank for the DSH to heat. As I have said before, homeowners need to do their homework to see if a buffer tank is justified for their particular situation.

I have a "thought experiment" to present that may shed light on this topic and help identify the most efficient setup.

There are two different scenarios to test. Each test is conducted in the same controlled environment. The air temp in the lab is controlled externally and the method to control the air ha no influence on the Test models.

*************************************
TEST SCENARIO 1.
Test model A: One Acme model 3000, 40 gallon size water filled with 120 degree water. No electric hookup and no DSH hookup. This is a stand alone tank full of hot water and not connected to anything. No plumbing connections. Nothing connected at all.

Test model B: One Acme model 3000 80 gallon size water heater filled with 120 degree water. No electric hookup and no DSH hookup. This is a stand alone tank full of hot water not connected to anything. No plumbing connections. Nothing connected at all.

Start the clock. 24 hours later stop the clock. Record the water temperature in all three tanks.

What is the theoretical expected results?
a. Should water temperature in A be hotter then B?
b. Should setup temperature in B be hotter then A?
c Both setups have the same water temperature?

Why?


*************************************
TEST SCENARIO 2:
Test model A: One Acme model 3000, 40 gallon size filled with 120 degree water. No electric hookup and no DSH hookup. This is a stand alone tank full of hot water not connected to anything. No plumbing connections. Nothing connected at all.

Test model B: One Acme model 3000 80 gallon size water heater filled with 120 degree water. Tank is plumbed to a functional DSH with AC running as would be throughout a typical summer day. No electrical hookup. Supply for water usage is not connected.

What is the theoretical expected results?
a. Should water temperature in A be hotter then B?
b. Should setup temperature in B be hotter then A?
c Both setups have the same water temperature?

Why?

******************************************
I look forward to the responses!

John

Bill,

Would it not be better to record the system status (running or off) in the graphs along with the other data? That way the true measure of temps over time are presented. One could see the data and make a correlation between ambient temps dropping when system turns off, and ambient temp rising when system turns on. In other words, see the system operation as a whole over time.

Thanks!
John
p.s. Please don't take this as a hit on your use of the WELSERVER. It is not meant that way at all.

John, you asked about which setup is the most efficient. I have been contending that there is more to the decision making process of the homeowner than efficiency. To illustrate, let's assume a buffer tank setup is more efficient. BUT, should homeowners get a buffer tank if they don't want to have it taking up space in their house? Should they get a buffer tank if they want to minimize leak potential and corresponding water damage? Should they get a buffer tank if the payback over the life of the buffer tank is $100, $250, $500, or $1000 (this is a personal decision and an analysis is needed to determine the amount of possible savings)?  Should they get a second tank if they can get most of the benefit with one tank? So, is a buffer tank right for 100% of people 100% of the time? My non-expert, but common sense, answer is no.

"Only a Sith deals in absolutes."  (Just a joke.)  Sincerely, Darth Buffer 

John, what you suggest was actually what I did at one time.  Temperature data would go back and forth between operating and ambient values, and another line would show ON vs. OFF.

After a while, the charts got to be tedious to look at, because you had to always look at another line to make sense of each chart.  Additionally, I learned the actual data is quite 'spikey.'  There are lots of spikes upward and downward at system starts and stops.

Other WEL users were commenting about the same thing, such that about 1.5 years ago the WEL developer enhanced the product with a sample and hold function.

After a while, I figured out what made the most sense for which values to sample and hold and which ones not too.  For example, room and outside temperatures are always real time.  It ends up being a personal preference to help make the most sense of the values.

No problem asking questions.  I always learn from others.

Best regards,

Bill 

Bill - Thanks for the explanation. I understand your reasoning for setting up the graphs this way. Creating managements systems for network traffic flow, we struggled with sample rates, displaying averages between samples and spikes that do not reflect the average. It looks like the same challenge here.

Did I miss the answers to these questions?
j