Where to start looking for Energy Savings

[sloeffle]

Now, here's my ignorance on DSH....will it get to 120°Fin the winter, or would the marathon still need to 'finish' the HW?

During the summer the DSH can definitely get water up to the high temp limit of 130F. I do not think during the winter it can get the water to 120F without the assistance of the Marathon.

The biggest "issue" that I have with the DSH on the furnace is that ONLY runs when the furnace is running. During the spring and fall my furnace might not run for a few weeks. We also have a wood burning furnace that I use during the really ( Jan / Feb ) cold months of winter or when the wife starts complaining about the house being too cold. The geothermal furnace will only see use during the middle of the night after the fire goes out.

During the cold months of winter the basement is easily 75F due to the excess heat from the wood furnace. The heat robbing in the winter does not really bug me since it is only costing me roughly 8$ - 10$ per million BTU's to heat the house with the wood furnace.

 

[woodgeek]

Agreed. In you're context, an overheated basement, even if insulated, is ideal for a HPWH.

 

[woodgeek]

Ah, but now we are back to elec usage. With a geo system AND a wood furnace, and good insulation why are you using 18 MWh/yr? I would dig into all the suggestions upthread, starting with killawatts on the fridge and freezer. The consumption of fridges has been falling rapidly even since the energy star program was launched.....if they are older (e.g. 90s) they might be part of the problem.

And I would still get the blower-door done. Any house that hasn't been pro airsealed is v likely to be leaky, and have 40-50% of the BTU loads be from air leakage. Ironically, this fraction was even higher in the houses built in the last 20 years, because the insulation was improved, while the airsealing was not.

 

[sloeffle]

Ah, but now we are back to elec usage. With a geo system AND a wood furnace, and good insulation why are you using 18 MWh/yr?

You hit the nail on the head IMHO. I always hoped it would be some phantom load. But as the chart shows, my electric usage when I was on vacation seemed very reasonable. That is the reason I started this thread so I could get some ideas outside of what I have already done.

The Kill A Watt meter comes today so I know what I will be doing all weekend. I have a feeling that I will probably have to bite the bullet and buy a Efergy.

 

[semipro]

Any house that hasn't been pro airsealed is v likely to be leaky, and have 40-50% of the BTU loads be from air leakage. Ironically, this fraction was even higher in the houses built in the last 20 years, because the insulation was improved, while the airsealing was not

and because many builders intentionally built leaky houses to try and avoid issues with "sick building syndrome" and related liabilities.

 

[woodgeek]

Indeed. Rather than airseal and install $100 bathroom fans and timers, or $500 low-end HRVs to get even better comfort and indoor air quality.

 

[sesmith]

Agreed that we're back to the building (or possibly the geo setup?). How many sq ft are you heating and cooling, and how much firewood do you also go through during the winter.

Also, is the desuperheater plumbed to a separate tank and not just into the water heater?

Sounds like you got an excellent deal on the HPWH. Have fun with the kill-a-watt meter. I know it was an eye opener for me. My biggest culprit, at the time was the old dehumidifier I had been running, which got replaced soon after. That and the stock tank.

 

[sloeffle]

We have approximately 2400' of pipe in ground for a 4 ton system. Half of the pipe is at 6' in the ground and the other half is at 4'. 4 tons is a little big for my heat and AC load but we decided that a bigger system was better since it is a 2 speed unit along with heat strips.

Below is the info from the Geolink report:

Design Data: Comfort Conditions:
Heating Load: 60,000 Btuh Heating Setpoint: 72 °F
Heating Temp Diff: 67 °F Cooling Setpoint: 77 °F
Cooling Load: 35,000 Btuh Start Cooling Temp: 78 °F
Cooling Temp Diff: 15 °F HW Temp Setting: 120 °F
Constant Fan: No HW Users: 3 people
Design City: COLUMBUS, OH Annual Loads:
Winter Design: 5 °F Heating: 93.0 million Btu
Summer Design: 92 °F Cooling: 16.8 million Btu
Bldg Bal Temp: 60.2 °F Hot Water: 13.6 million Btu
Internal Gains: 10,563 Btuh HW Use - Daily: 55.0 gallons

House Info:

1400 sqft modular on a crawl space. House is approximately 10 years old. 2x6 exterior walls with batt insulation. Approximately 12 - 14" of cellulose in the attic. No access to the attic.
768 sqft addition on a full basement. Basement has a walk out. I was the GC on the addition. 2x6 exterior walls, spray foam insulation, R-60 in the attic.

Also, is the desuperheater plumbed to a separate tank and not just into the water heater?

Into the water heater.

For now I do not have much choice but to run the 250W stock tank heater during the winter. I looked into a Ritchie EcoFount but I would be about 1K deep by the time I got it installed.

 

[TradEddie]

The Kill A Watt meter comes today so I know what I will be doing all weekend. I have a feeling that I will probably have to bite the bullet and buy a Efergy.

One note on using the Kill A Watt on fridges and freezers, you need to leave it recording for several days. Depending on the model, there is a defrost cycle initiated every few days. On my fridge/freezer, this is simply a huge halogen bulb that boils water off the coils every 36 hours. Sounds bad, but it doesn't run for long, but in addition to the regular compressor cycle, you need to have a few defrost cycles included to get a better idea of consumption.

With CFLs/LEDs, smart power strips and a recent Geospring, I've been able to cut over 20% from my electric bill and we are now well below 10MWh/year. There were very few surprises with the Kill A Watt for me, but it's good to see where all that electricity is going.

TE

 

[sesmith]

I'm certainly no expert on this stuff, but I can give you some data points for comparison.

Our house is also 1400 sq ft. We are in the warmer area of zone 6, just a little colder than you in zone 5. Our house is a 170 year old farm house with many improvements. In 2011,when we put the geo system in, the house wasn't as tight as it is today, but we are probably not as well insulated and air sealed as your place is.

Some specs for our system design were:

71 Mbtu heating
11.5 Mbtu cooling
10.6 Mbtu water heating
winter design 2 degrees
heating setpoint 70 degrees
2000 ft of loop buried 7 ft average depth
3 ton Climatemaster tranquility 27 with desuperheater

Our monthly average electric usage since the geo system was installed has been around 1050 kwh. The highest month being Jan at 1600-1800 Kwh and the low months in the summer 750-850 Kwh. We have 2, and over the last year, 3 in the house. We are not using any other heat source with the exception of about 4 fires I made in our wood stove last winter rather than use aux heat those nights. We like our house cooler than you do, and set our tstat to 67 without setbacks in the winter. We air condition down to 71 when we use it, but it doesn't get a lot of use.

I would continue to search out energy hogs at your place. Don't forget things like the well pump. You can put a current probe on the legs out to it in your box and rule out leakage to ground.

If you find nothing, I would suspect your heating system might be oversized and you are just paying a little more to run the system than you would if it were sized smaller, but this is just a guess. The fact that the desuperheater doesn't have it's own tank is likely the reason you didn't notice any savings with it on in the winter. Below is a link explaining why a separate tank is needed...see post #5.

(broken link removed)

If you have any geo questions, the forum I linked to above is a great place to ask them. The guys there could probably help you tweak your system, if necessary, to get the most out of it.

You could also have an energy audit done on the house, with a blower door test, to make sure there are no surprises with the building envelope.

edit....I just reread your post above and noticed you mentioned a 765 sq ft addition. Was this part of the original heat load calcs ? If so, you are definitely better insulated than we are. If not, then your electical usage is probably right on par with what we use, especially considering your tstat set point.

 

[woodgeek]

Along the same lines, you could get an efegy now, and put it not on your whole house to chase phantoms, but instead on your aux line, to check that you are not calling aux a lot, or on your geo ground loop pump, to estimate its usage. The quoted COP on a geo usually excludes the pump usage, and some installers put in a monster pump (to avoid callbacks?) and then system COP is much lower than expected. A few mos of efegy data would let you rule those ideas out.

 

[sesmith]

Interesting side note. For 2014, our usage will be higher...closer to 1200 Kwh/ month instead of the running 1050 Kwh average we had. Part of the reason is the colder Jan-March season this year, but 75-100 Kwh of this can be directly traced back to having my son back home temporarily. We'll call that the "son effect" Try and measure that with a kill-a watt-meter A minimal charge for some of the work he helps me with around here.

 

[sloeffle]

2000 ft of loop buried 7 ft average depth

Impressive. We have clay here and started hitting sand stone at 6' feet. I really wish all of my pipe was at 6' but that would cost me another 2k.

The fact that the desuperheater doesn't have it's own tank is likely the reason you didn't notice any savings with it on in the winter. Below is a link explaining why a separate tank is needed...see post #5.

Yeah my HVAC guy told told me that I should have two tanks also. I was already over budget on the addition so I opted just for one tank. If I had to do it all over again, I would not get the DSH. The money that I spent on a DSH would of been used for a high end HPHW. If I lived in south and used a lot of A/C I would get a DSH.

I just reread your post above and noticed you mentioned a 765 sq ft addition. Was this part of the original heat load calcs ?

Yes the addition was part of the heat calculations.Total home square footage is 2172. House is a ranch.

Don't forget things like the well pump.

Good point. I might shut it off for a awhile and see if I notice and difference in our daily usage. We only use well water for the livestock watering.

Along the same lines, you could get an efegy now, and put it not on your whole house to chase phantoms, but instead on your aux line, to check that you are not calling aux a lot, or on your geo ground loop pump, to estimate its usage. The quoted COP on a geo usually excludes the pump usage, and some installers put in a monster pump (to avoid callbacks?) and then system COP is much lower than expected. A few mos of efegy data would let you rule those ideas out.

The geo system has two Grunfos pumps on a Waterfurnace flow center. As I understand it from the HVAC guy, the pumps are matched by Waterfurnace to the furnace and type of loop field that you have. While running in first stage the furnace, pumps, and DSH pull 22AMPS at 240V. We rarely hit second stage since I generally use the wood furnace when temps are really cold. The aux heat is not hooked up. It would cost me $4.60 an hour if I would need to run it.

We'll call that the "son effect"

I have the wife and daughter affect. They love their long hot showers.

 

[sloeffle]

Kill A Watt Update - All kw usage is for 24 hours.

Basement Freezer and Refrigerator = 2.5kw

Dehumidifier = 14.4kw

Plugged the Kill A Watt into a couple things for grins

DSL modem, Wireless router, and Dish Hopper = 60W combined

DLP TV = 190W

Luckily we do not watch a lot of TV and the Hopper turns itself off after a few hours of non use.

 

[woodgeek]

The geo system has two Grunfos pumps on a Waterfurnace flow center. As I understand it from the HVAC guy, the pumps are matched by Waterfurnace to the furnace and type of loop field that you have. While running in first stage the furnace, pumps, and DSH pull 22AMPS at 240V. We rarely hit second stage.

Eeenteresting. 22A*240V = 5.28 kW in first stage. You sure about that?

A nominal 4 ton unit would put out 48 kBTU/h, or 48000/3414 = 14 kW of heat. 14 kW/ 5.28 kW = COP = 2.66. And this is assuming that the 22A is for the nominal second stage output! While its prob an error, true COPs (including pump power) less than 3 are common with older geos.

 

[woodgeek]

Kill A Watt Update - All kw usage is for 24 hours.

Basement Freezer and Refrigerator = 2.5kw

Dehumidifier = 14.4kw

Plugged the Kill A Watt into a couple things for grins

DSL modem, Wireless router, and Dish Hopper = 60W combined

DLP TV = 190W

Luckily we do not watch a lot of TV and the Hopper turns itself off after a few hours of non use.

I assume these numbers are Kwh/day, not kW....otherwise how big is a 14 kW dehumidifier?

 

[sloeffle]

Eeenteresting. 22A*240V = 5.28 kW in first stage. You sure about that?

I put an amp clamp on one of the hot legs coming into the furnace and it read 11 amps. My assumption ( please correct me if I am wrong ) that I need to double that since it is 240V.

According to the Waterfurnace doco ( search on Copeland Ultratech ). First stage is 67% of capacity. 2.68 tons in my case.

Furnace is only three years old.

I assume these numbers are Kwh/day, not kW....otherwise how big is a 14 kW dehumidifier?

Correct. Sorry I don't have all of the lingo down.

Dehumidifier pull 600 watts. (600W*24hours) /1000 = 14.4Kwh/day

 

[woodgeek]

I put an amp clamp on one of the hot legs coming into the furnace and it read 11 amps. My assumption ( please correct me if I am wrong ) that I need to double that since it is 240V.

According to the Waterfurnace doco ( search on Copeland Ultratech ). First stage is 67% of capacity. 2.68 tons in my case.

Furnace is only three years old.

Correct. Sorry I don't have all of the lingo down.

Dehumidifier pull 600 watts. (600W*24hours) /1000 = 14.4Kwh/day

No bigs. 11A in both legs at 240V is 240*11=2640W or 2.64 kW. Each leg is only 120V to ground, but 240 with respect to each other.

2.68 tons is nominally 2.68*12,000 BTU/h = 32,160 BTU/h or 32160/3414 = 9.42 kW_thermal. Your nominal COP is 9.42/2.64 = 3.57 if the BTU number is correct. Sensible.

If you need 93 Million BTU/season, then at COP = 3.57, this is 93000/(3.414*3.57) = 7630 kWh/yr for heating if you used no aux, and no second stage (or if the second stage has similar COP). Of course, this number is no more accurate than the 93 MMBTU estimate, but it seems compatible with your annual usage having some other bigs loads, and letting the geo off the hook.

I'm back to thinking about airsealing, probably attic and crawlspace and addition. 93 MMBTU seems a bit high for your square footage, even in OH. Is there access to the attic from outside the house?

What is your total conditioned square footage again? Degree days?

 

[semipro]

RE: the well pump. A bad foot valve can result in the pump running too much to compensate for the leakage.

You don't have a hot tub do you? One of our members here learned his was an energy hog after some sleuthing.

 

[TradEddie]

Dehumidifier pull 600 watts. (600W*24hours) /1000 = 14.4Kwh/day

That's huge if its running 24/7 at that rate, if its is, stop looking any further, that's 5000kwh/ year right there. For any intermittent cycle device, you need to measure the consumption over a longer period, not just its wattage when running. There's a button on the KAW that does that for you.

The well pump is worth checking, I had a $70+ bump in my electric bill when a leak developed in the line, took me two bills to start looking for the culprit, no symptoms with water pressure, but easily spotted when the line didn't hold pressure with pump breaker off.

TE

 

[sloeffle]

Total square footage is 2172. The house is a ranch.

6243 heating degree days and 670 cooling degree days ( http://www.clrsearch.com/Marengo-Demographics/OH/43334/Weather-Forecast-Temperature-Precipitation ). The Geolink report was built off of Columbus Ohio so their numbers will be a little different than ours. Columbus tends to have less heating degree days and more cooling degree days.

Attic over the modular is not accessible. Attic over the addition is.

Here is most of the Gelolink report. You nailed the COP BTW. I was on the fence about either putting in a ASHP w/ propane or a geo. With the govt rebates and coop rebates the price almost ended up being a wash. Our price of electric has gone up from .14Kwh to .16Kwh







And for grins. The ASHP w/ propane info:

 

[sesmith]

Impressive. We have clay here and started hitting sand stone at 6' feet. I really wish all of my pipe was at 6' but that would cost me another 2k.


Yeah my HVAC guy told told me that I should have two tanks also. I was already over budget on the addition so I opted just for one tank. If I had to do it all over again, I would not get the DSH. The money that I spent on a DSH would of been used for a high end HPHW. If I lived in south and used a lot of A/C I would get a DSH.

The 2000 ft I mentioned included 100' out and back to the loop field. Loop field is 3 runs 300' out and back racetrack style, so 1800 ' total there. There are some things I dislike about where I live (like winter) but our soil for geo is not one of them. No problem getting to 7' with a big excavator. Wet clay soil with water moving through, perfect for heat transfer.

A couple of points on geo systems, though. A DSH is not just cost effective in the south. The same argument could be used for a HPWH. The heat has to come from somewhere. In the case of the HPWH it comes from the heat in the building, with the DSH, it comes from heat off the compressor. Both types of water heating are a load in the winter, and free heat in the summer. A DSH, if set up right is more efficient, so one could argue a better investment. I'm not totally convinced of that one, as the HPWH also has the benefit of doing some dehumidification, which could make it the winner in the long term. FWIW, the second tank for the DSH is often just a 50 gal electric water heater without the elements hooked up, not a big cost for the DSH to run efficiently.

As far as efficiency of a geo system goes, you can't really make any guestimates of efficiency based on what the system should put out in terms of heat. GEO systems are dependent totally on the quality of the installation. A couple of small changes in design can cripple an otherwise very efficient geo unit. The only way to check things and come up with a number is by doing some testing and finding out what the actual heat of extraction of the unit is. This number can be compared to a chart the factory includes in the owner's manual to see how well it is operating. To actually do the testing, you need to know 5 things...current and voltage, which you can measure at the panel, incoming loop temp, outgoing loop temp, and flow through the loop. This will measure everything, including pumping, blower, etc. It does not take into consideration duct losses, just the efficiency of the unit itself. The link below will link you to a document that explains how to do the testing. It's not too hard to do.

(broken link removed to http://www.geoconnectionsinc.com/bookstore/forced_air_efficiency_measurement.html)

I spent quite a bit of time playing with my system one winter and found a couple of surprises. Contrary to popular belief, second stage is just about as efficient as first stage, so I never let it concern me when second stage is on. A 2 stage heat pump is made to use both stages when it is sized correctly. To size a heat pump so second stage doesn't get used means you are paying more to run an over sized system most of the time. Even aux heat, when it runs, is not that much of a hit, so long as it's not running too much. Most of your heat is still coming from second stage operation, and the aux strip is just supplementing that. You aren't running at COP=1, at that point, but probably closer to COP=2. Over an hour period, aux may just cycle a small part of that, so the actual COP over a longer period is still much higher. That said, excessive aux use due to a problem with the heat pump system will quickly run your electric bill up.

On the dehumidifier, I tried things like putting it on a timer to try to save money (we have separate day/night electric rates) but found that was pretty useless if I wanted it to actually work. I've just accepted it as one of the energy hogs I live with. A couple of aquariums are another. The horses are gone now, so the stock heater is history.

 

[sloeffle]

You don't have a hot tub do you? One of our members here learned his was an energy hog after some sleuthing.

No hot tub here.

I shut the well off yesterday. I put an amp clamp on the electric leads coming into the box before I shut it off and the usage was <1 amp. However, I might not of possibly caught it cycling.

For any intermittent cycle device, you need to measure the consumption over a longer period, not just its wattage when running.

I agree. The cold weather has brought an end to having to dehumidify the basement. I let it run for about a 30 minutes and checked on it every few minutes and it didn't fluctuate much from 600 watts. The low setting was only 50 watts lower than the high setting. Obviously the low setting is there to make you feel better.

 

[semipro]

I shut the well off yesterday. I put an amp clamp on the electric leads coming into the box before I shut it off and the usage was <1 amp. However, I might not of possibly caught it cycling.

Its not that the pump uses more power than it should when its operating.
The problem typically arises when there's a leak of some sort in the system and the pump runs more than it should.
One way to check is to turn of the pump breaker and the main supply valve between the house and pump/tank and then watch for a pressure drop.

 

[sesmith]

I don't think you will find any smoking guns based on the report you posted, though I'm sure you will find some savings using the kill-a- watt meter. According to the geolink report, if you use the geo system for all your heating and cooling you can expect it to account for 921 Kwh / month. Your average total is around 1450 Kwh / month. That leaves around 530 Kwh for everything else. The only unknown is how much heating your are supplementing with wood. If you're using a lot of wood, maybe there's a problem somewhere. If not, you're right on target.