Dewayne, consider using the 'Ruggedized Temperature Probe' from http://www.embeddeddatasystems.com .

"The RTP temperature probe is designed for wide temperature range applications requiring excellent chemical resistant properties and sensor submersion."

"All exposed parts of the RTP are manufactured of either stainless steel, or Teflon based products, resulting in excellent chemical resistance properties to acids, alkalis, ketones, esters, aliphatics, aromatics, and outdoor exposure.  The probe is constructed of 304 Stainless Steel making it both durable and water resistant to 60 PSI.  The cable used on this sensor is Belden’s 7928A CAT 5, which uses Teflon based materials for both the outer jacket and inner conductor insulation.  This cable is particularly suited for harsh environments, and offers excellent resistance to high and low temperatures, oil, gasoline, and sunlight exposure.  The RTP probe is manufactured using a Teflon based heat shrink tubing that creates a water tight seal at the cable’s point of entry into the tube.  This results in a sensor that can be submerged beyond the top of the steel probe."

Downside to these sensors are cost ($50 each on retail basis) and teflon cable length limit is 12 feet.

Hope this helps.

Best regards,

Bill

Dewayne, you're going to hook up 1-wire technology sensors to what I call a '1-wire network cable,' regardless of what kind of sensor it is (raw temp sensors, RTP sensors, RH sensors, etc.).

You'll locate your WEL at a place where it's easy to make a network (Ethernet) connection.

From the WEL, you'll have a '1-wire network cable' travel to wherever your sensors are.

Ideally you'll maintain a 'linear topology' - one '1-wire network cable' traveling around to sensor locations, with each sensor 'pigtailed' to the cable, with about at least a foot of distance along the '1-wire network cable' between sensor splices.

(The WEL's 1-wire interface is exceptionally tolerant of cable noise, though, and thus offers good accommodation of a '1-wre network cable' branch.  Make this your second choice, though, if you end up with a lot of sensors, or with long cable distances.)

The actual material for the '1-wire network cable' can range from CAT5 to simply a couple of 'bell wires.'  Generally you're only going to need 2 wires - signal and ground (RH sensors being the exception, where a 3rd wire is needed).  CAT5 cable will offer the best noise immunity - important, though, only in cases where there's a lot of sensors, or where there's a lot of distance to the sensors.  If using CAT5 cable, only 1 of the 4 wire pairs is used (generally).

For the RTP sensors, you'll need to have your '1-wire network cable' within 12 feet proximity.  Simply splice the RTP sensor wires as a 'pigtail' to the '1-wire network cable.'  I use small wirenuts to ensure a solid, mechanical, no-future-problems connection.  This splice connection will need to be someplace environmentally shielded (hence my earlier comment that only getting 12' of teflon cable could be a limiting factor, although you could purchase a spool of the Belden teflon cable to extend out the distance to sensor locations, with waterproof splice connections).

The image below is an example of a sensor connection to my '1-wire network cable.'  It was a first attempt to measure my EWT and LWT.

The gray cable is the CAT5 '1-wire network cable.'  A temp sensor is glued and mechanically fastened to the 2" HDPE pipe, and then is 'pigtailed' to the '1-wire network cable.'  Then, down a foot or so on the '1-wire network cable,' another temp sensor is 'pigtailed' to it.

It's actually more complicated to describe than it is to do it.  It isn't more than a 5 minute job to make the connection.

Best regards,

Bill

Farmboy, thanks for the comments.  There are many smart people here and I've learned a lot from them.

engineer, water flow is hard as a retrofit because of the effort required to put in a meter into already existing HDPE pipe.  For those that know, in advance of installation, that they'll have some kind of instrumentation system, like a WEL, insertion of a pulse-output flow monitoring device is pretty straight forward.  The WEL can accommodate pulse-output flow meters without difficulty.

As far as planning for optimal use of an instrumentation system, like a WEL, gosh, the 'sky is the limit.'  Take a look at http://welserver.com/ww/ for implementation ideas.  And 5 of the more advanced implementations are listed on the left side of the screen.  All of my implementataions can be seen at http://welserver.com/WEL0043/ .

Climate is the variable that largely affects how much heating/cooling load a residential structure has.  The WEL easily accommodates temp and RH measurement.  And Dew Point and Degree Days are easily calculated.

Heat that has to be added/removed from the home is the response to climate, and is the driver that influences cost of running HVAC equipment.  DeltaT temp across the water-to-gas heat exchanger is easily measured.  With a flow meter hooked up too, that gives you Heat of Rejection or Heat of Extraction on an instantaneous basis (KBTU/hr) or accumulated (KBTU).  (Since many GSHP implementations have a constant water flow, like me, you can accurately measure it by hand, and then use the WEL to do the calculation.)

Power/energy are very straight forward.  Just hook up the monitors where you want them.  Biggest downside to monitoring power is the cost of the monitors.

If you're monitoring HE/HR (above) and you have a power monitor on your GSHP unit, then you have opportunity to have COP in real time.  (I can do this by hand, but, can't do it real-time because I only have one power monitor for both of my GSHP units).

If you're skilled enough with HVAC, you can put in RH and temp sensors in the supply and return air plenums, and determine sensible and latent cooling capacity.

Air flow is straight forward if you have variable speed blower motors - designed to maintain a set cfm as filters, etc. get dirty.  And by measuring DeltaT across the evaporator coil, now you've got Sensible Cooling / Heating Capacities without difficulty with the WEL.

EER is tough to accurately get real-time because you need to know Total Cooling performance.  And this means you need to know the Latent Cooling performance.  I'm not aware of a 1-wire technology wet bulb temp sensor, which is what you'd need.  I do the calculate 'off-line,' and have to assume a Sensible/Total Cooling ratio that I look up in the specs to match up with my EWT.

There are many examples of WEL users monitoring their photovoltaic sensors and thus how much power contribution they're making to/from the grid.

Desuperheater performance monitoring is all quite capable with the WEL.

Putting sensors into the ground to facilitate monitoring water loop performance is straight forward.

WEL1000 is an example of radiant floor monitoring - see http://welserver.com/WEL1000/ .

Hope this helps stimulate some thoughts.

Best regards,

Bill

Dewayne, congrats!  I see you're up and running with a WEL unit.

Looks like your water temp sensors are located in a conditioned place.

Best regards,

Bill

My Leaving Air Temp for my 3 ton unit Envision WaterFurnace GSHP routinely averages 45°F, when running 1st stage.  Air flow is set at 750 cfm, which would make it 375 cfm/ton.  I believe WF accomplishes this by including in the Envision series a very large evaporator surface area.

Outside Dew Point for the Dallas area, at the moment, is ranging from 60+° lows (recent days) to 74+° highs (a couple of weeks ago, when it was blistering hot).  This is a commonly reported measurement on all of the weather channels.  Simply using http://www.weather.com , for Dewayne's ZIP, I see that at the moment it's 85°, with an RH of 17%, resulting in a DP of 36°.  This is weather we would never see in the Dallas area.

I too pay attention closely to DP, as I run outdoors a lot for exercise.  Many times, when I can, I choose my time of day to go out based on lowest DP.  Not surprisingly, it's in the late morning for me, when temperature is still low (relatively speaking) but RH has already been coming down.  This summer, evening time when the sun was gone, was still at a much higher DP temp than the mornings in spite of the sunshine.

I have DP charted on one of my WEL graphs for the past 20 days.  I'm using my outdoor dry-bulb temperature and outdoor RH sensor, and using the WEL to compute DP based on a formula from Wikipedia.  I'm consistently 5 - 6° higher than what the channel says for my location, but, at least it's consistent.  I don't know why I can't get DP numbers closer to actual.

I agree with engineer's comments on comfort related to DP.  If I had a GSHP that had a blower motor 'slow down port,' and I was an inventor, instead of the thermostat I'd use some kind of a 'Dewpointstat' to turn on/off my HVAC.  I know this is how it's done in commercial and industrial settings.

Best regards,

Bill

engineer:

I didn't know that large evaporator coils favor EER at the expense of dehumidification.  Given this, I think another way of saying this is that large evaporator coils increase sensible cooling capacity at the expense of latent cooling capacity - I didn't know this either.

My observation has been that I have pretty short cycling, which would normally be at the expense of dehumidification.  But, I'm able to average an indoor RH of 42% (last 30 days) in spite of this.  I have (perhaps erroneously) been attributing this to a lot of dehumidification in a short period of time due to what's pretty large for an evaporator coil.

Last year I too looked at running the blower continuously, like advertising suggests to do.  It doesn't work for my climate, just as you learned.  Here's a chart of what actually happens to the water in the coil, courtesy of a Lennox study: http://www.pbase.com/neukranz/image/88853062 , showing that the water in the coils becomes a significant latent addition when running the blower without the compressor.  And here's what my coil actually looks like right after a cooling cycle: http://www.pbase.com/neukranz/image/84712917 .  I shot this, thinking that the 'problem' was simply water sitting in the pan.  It's not - the coil is substantially loaded with water.

I didn't know that dehumidification capability is primarily dependent on CFM/ton.  I thought RH removal was also dependent on latent cooling capacity, evaporator coil size, and degree of cycling.

My Entering Air Temp averages about 77°F.

Dallas weather at the moment is 72°, 95% RH, and 71% Dew Point.  My indoor RH has varied from about 39 - 44% this cooling season.  It goes up when the GSHP units are not running, and goes down very easily when the units are running.  I don't have a very air tight home, further causing me to think that my Envision units' dehumidification ability is pretty strong.

I'm pretty sure on the blower motor speed setting - I set it to 750 CFM because I wanted to air balance the supply outlets at the highest air velocity, regardless of cooling or heating mode (750 is the minimum for heating). 

My 375 cfm/ton was arrived at by taking 3 tons * 0.67 (1st stage) = 2 tons, and dividing 750 by 2.  If in fact I'm running at 2.5 tons on 1st stage, then my air volume is 300 cfm/ton, further favoring RH removal.

Yes, an avg of 42 KWH per day for misc stuff usage seems pretty extravagant to us.  We were surprised to see how it all adds up.  During the day, when no one is home, and all lights and everything possible is turned off, we can get this down to 800 watts (about 20 KWH / day).  Almost all of this is heat contributing - particularly computers and computing equipment, and refrigerators.  Then add to this microwave, electric oven, entertainment items, etc.  At least we're a 100% CFL home now - that contributed about 12 KWH / day savings when we made this change.

Thanks for the note - interesting subject.  Nice to have a WEL to put numbers to the thoughts.

Best regards,

Bill

I did look at those, but if all the pumps are off I would think rather quickly the coil would come up to temp and dry off.  When it is cooling the coil is dripping, almost running water and that doesn't add any humidity to the house since it is water condensing out of the air and on to the coil correct?  Or is it because that water loaded in the coil could otherwise drain off and wouldn't be re absorbed to the home?