QUESTIONS REGARDING THE REPLACEMENT OF AN EXISTING SYSTEM

NO PROBLEM DUC...

...HI JOHNSP...YES THE HOUSE IS 5200 SQUARE FEET / 10 FT CEILINGS WITH TWO ZONES BUT THE POWER COSTS IN CT IN THE SUMMER OF 15 CENTS PER KWH ARE OUT OF SIGHT RESULTING IN $700 POWER BILLS...FREUS USES YOUR STANDARD CONDENSER, BUT INSTEAD OF RELYING ON AIR BEING SUCKED THROUGH COILS TO COOL AND CONDENSE THE R-22, THEY HAVE AN INTERNAL WATER BATH...NATURALLY..WITH WATER MOLECULE MORE HIGHLY CONDENSED THEN AIR MOLUCLES, THE WATER CAN REMOVE 3500 TIMES MORE HEAT THEN AIR...THE OTHER GREAT THING ABOUT WATER COOLED CONDENSERS IS THAT AS THE AIR TEMPERATURE GOES UP, THE SEER (OR EER IN WATER COOLED CASES) DOESN'T GO DOWN.

REMEMBER, WITH AIR COOLED SYSTEMS, AS THE TEMPERATURE GRADIENT BETWEEN OUTSIDE AIR AND THE FREON RUNNING THROUGH THE CONDENSER SHRINKS, THE SEER RATING DROPS. SEER TEST RATINGS USE A OUTSIDE AMBIENT TEMPERATURE OF 82 DEGREES TO DEVELOP THE ENERGY RATING...WHEN A 14 SEER UNIT IS RUN IN OUTSIDE TEMPS OF 95 DEGREES, THE SEER DROPS TOP 12.17 AND AT 115 DEGREES OUTSIDE TEMP, THE SEER DROPS TO ABOUT 10.25...THAT'S WHY FOLKS IN THE SOUTHWEST USE WATER COOLED CONDENSERS...BASICALLY, THESE WATER COOLED UNITS HAVE AN EER OF 18 AND ROUGHLY A SEER OF 21 OR 22...

THE OTHER OPTION MIGHT BE A GAS FIRED CONDENSER...PROPANE COSTS THIS YEAR ARE 1.75 PER GALLON SO I WAS WONDERING IF ANYONE HAD ANY EXPERIENCE WITH EITHER OF THESE SYSTEMS...WILL CALL FREUS TOMORROW OF COURSE BUT THOUGHT SOMEONE HERE MIGHT HAVE SOPME EXPERIENCE...

Quote:

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Originally posted by kevin57

REMEMBER, WITH AIR COOLED SYSTEMS, AS THE TEMPERATURE GRADIENT BETWEEN OUTSIDE AIR AND THE FREON RUNNING THROUGH THE CONDENSER SHRINKS, THE SEER RATING DROPS. SEER TEST RATINGS USE A OUTSIDE AMBIENT TEMPERATURE OF 82 DEGREES TO DEVELOP THE ENERGY RATING...WHEN A 14 SEER UNIT IS RUN IN OUTSIDE TEMPS OF 95 DEGREES, THE SEER DROPS TOP 12.17 AND AT 115 DEGREES OUTSIDE TEMP, THE SEER DROPS TO ABOUT 10.25...THAT'S WHY FOLKS IN THE SOUTHWEST USE WATER COOLED CONDENSERS...BASICALLY, THESE WATER COOLED UNITS HAVE AN EER OF 18 AND ROUGHLY A SEER OF 21 OR 22...

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SEER considers efficiency throughout cooling season, not just during the hottest summer afternoons. At 95 degrees, we're talking about EER. Higher SEER units also tend to have higher EERs, but this isn't a perfect correlation. This has always been true... so your 9 SEER systems probably run at an EER of about 7 in hot days.

Freus is interesting, but if I were in your shoes, I wouldn't touch one. See if you can find an experienced Freus technician in CT before you even think about buying one. It seems awfully risky to go with this technology and then face the risk that you can't keep it working with local know-how. People in the southwest use water cooled condensers (or evaporative coolers) because they are particularly effective in the very dry conditions they have there. Even still, Freus is by no means common, even in the desert southwest. The advantage of evaporative techniques falls way off when you get into humid ambient conditions, though, so you're going to see even less of that used outside of the desert.

If you really want to save on operating cost, you'd be better off considering geothermal. Then you could save on both heating and cooling costs. It's very expensive to install, but with that much space and those utility rates, it will pay for itself. Good geothermal techs are probably scarce in CT, but you're far more likely to find somebody to work on geothermal there than an evaporatively cooled system.

Also don't forget that you can often do yourself good service economically by putting money towards other energy improvements (windows, insulation) that reduce your need for heating and cooling in the first place- before you assume that you need the highest efficiency equipment available. And absolutely get a serious load calculation done, or use the HVAC-Calc software to do your own, to make sure that you're getting the right sized equipment. Oversized equipment will absolutely never achieve its rated efficiency, yet many contractors will use rules of thumb instead of serious math to guesstimate what size of equipment they'll use. From my experience in buying central cooling systems, the guesstimators will routinely try to sell AC systems 50% bigger than the correct size. This results in impaired humidity control and pitiful efficiency. They typically do about the same thing with furnace sizing, although the results of furnace oversizing aren't (quite) as bad.

I haven't run the numbers lately, but gas air conditioning isn't economical in the southwest anymore (it used to be common there), and their electric rates are on the high side, too. I doubt that it will prove cost effective in CT, especially with propane instead of natural gas. If it were cost effective, it would be more common!

Finally, don't forget that it's not cheap to heat and cool 5000 square feet anywhere, regardless of utility rates and equipment efficiency. The careful setup and use of zoning (either through zone control, separate systems, or hybrids like some mini-splits) can save money by reducing how much space conditioning you put into unoccupied spaces, but even still, it's a lot of space.

Hope that helps.

[Edited by wyounger on 03-21-2005 at 09:48 AM]

I agree 100%. Water cooled and gas fired condensers are only seen in very large commercial installs. Buildings get special gas rates for AC to save on electricity demand for the utility. You won't get this for a residential home. Use of city water is not code in NYC for cooling, you must recirculate and cool the water with a fan forced tower which uses power also. Again this was done to locate condensers inside a building without outdoor access to air cooling more so then for efficency.

Anyone would question why a 5000 sq ft house needs 8.5 tons of cooling in CT. We need AC 3 months of the year and maybe 1 week of 95° days. Humidity is the killer. Insulate the envelope and zone it well for comfort and you'll keep humidity at bay with lower operating and initial system install costs.

Geothermal is very very nice. The biggest drawbacks are the initial investment being rather high, and being able to dig a well for the water loop.

Here's a link that will get you started in the right direction....
http://www.geoexchange.org/about/activities_ny.htm

NY is the closest I could find to you.

Here's another site you can get info from
(not sure of the brand name(haven't worked on many geothermals here), I thought its a nice site to get info from though.
http://www.geocomfort.com/?page=home

There aren't very many geothermal's around here.
I've worked on one where I asked the homeowner how his utiilities are.
His house is a rather large 4 bedroom two story.
His light bill is never over a hundred dollars.
He got a bill one time for over 350 bucks. He called the light company out and cussed em up and down.
After he slammed the phone down he looked at the bill only to realize it was his next door neighbors. The postman got the mailboxes mixed up. Both houses are about the same size.

A geothermal heat pump might work real well for you there too, not only saving electricity in the summer, but also save in the winter. A geothermal heat pump's not effected by outside temps as much as air exchange.

Johnsp mentioned high humidity for you guys in the summer.
Consider a variable speed blower on your unit also.
This will allow the equipment to remove more humidity during a run cycle.

Get your duct system evaluated also. Air leaks on any system sucks (literally.... whatever air leaks out of your ducts to outside... the same amount of air gets 'sucked' back into the house from where ever it can... i.e. pull down stairs, light fixtures, etc)

ON a side note....
might help if you start off your posts with...
"Excuse the caps, special keyboard types all caps"

ALSO on another note....
I'm most appreciative of your service for our country.

There is a memorial in our little town that lists soldiers who've laid down their lives for our country. It lists names who've faught in WW1, WW2 (section for pacific and section for europe), Korea, and Vietnam.
Across the top are the words....
"They've given their today for your tomorrow"

Although your name may not be upon a wall giving you gratitude for your service. THere are many that proudly stand for the soldiers and our liberty in which they protect.







[Edited by wormy on 03-21-2005 at 05:24 PM]

Wheres the water going to come from.
If from a well, then consider geothermo heat pumps.

Did a bit more digging....
found this contractor in connecticut

http://www.nutmegmechanical.com/geo.htm

HI FOLKS (SPECIAL KEYBOARD EQUIPMENT ONLY TYPES CAPS)

...THANK YOU ALL VERY MUCH FOR ALL OF YOUR SUGGESTIONS AND ESPECIALLY TO YOU WORMY FOR YOUR VERY KIND WORDS....

...I'M STARTING TO GET THE FEELING THAT I'M JUST A CHEAP CONNECTICUT YANKEE (WHO HATES THE LOCAL INEFFICIENT UTILITY)..THE HOUSE IS 14 YEARS OLD, WITH R38 IN THE CEILIINGS AND R19 IN 2X6 WALLS WITH 5200 SQ FT AND 10' CEILINGS. DOORS AND WINDOWS ARE MARVIN DOUBLE INSULATED SO ENVELOPE IS REALLY TIGHT...FAILED TO MENTION THAT WE HAVE OIL FIRED BASEBOARD HEAT (SEPERATE BOILER) WHICH ACTUALLY IS PRETTY EFFICIENT IN THAT IT BURNS BETWEEN 1600 AND 2600 GALLONS OF FUEL A YEAR...NORMALLY, IN ORDER TO KEEP THE A/C BILLS TO $350 PER MONTH WE SET THE A/C TO 78 AND THEN USE ROOM FANS TO MOVE THE AIR AROUND WHICH WORKS...

I'LL LOOK INTO THE GEOTHERMAL...WE DO HAVE MUNICIPAL WATER SUPPLY SO WATER IS NOT A PROBLEM...WERE WE WILL RUN INTO PROBLEMS IS WITH THE UNDERGROUND SYSTEMS..ALTHOUGH WE HAVE 2.25 ACRES OF PROPERTY...1.5 ACRES IS CONSERVATION LAND AND THE OTHER .75 IS TIED DOWN WITH A LARGE LEACHING FIELD + SEPTIC, HUGE DRYWELL SYSTEM TO REINJECT ROOF WATER INTO GROUND WITH ZERO RUNOFF, UNDERGROUND UTILITIES ETC ETC. MY GUESS IS THAT WE WOULD NEED A SHOEHORN TO GET A GEO SYSTEM IN BUT IT'S WORTH A LOOK AT.

ALSO, I SHARE YOUR CONCERN ABOUT A FREUS SYSTEM LOCATED IN CONNECTICUT..HATE TO BE THE FIRST ONE TO TRY IT AND FAIL! I'LL CHECK WITH FREUS AND SEE WHAT THEIR RESPONSE IS THEN I'LL POST IT FYI BUT I HAVE THE FEELING THAT WE MAY END UP JUST BUCKING UP FOR A 14 SEER, HIGH EER WITH VARIABLE SPEED BLOWER AND LIVE WITH IT...STILL BEATS 9 SEER 7 EER RIGHT?!

ALSO THANKS WYOUNGER FOR THE SEER /EER COMMENT...I UNDERSTOOD THE TEMPERATURE DIFFERENTIAL BETWEEN THE TWO (82 VS 95 DEGREES) BUT I NEVER PUT TOGETHER THE SIMPLE CONNECTION BETWEEN THE TWO...EER IS A GOOD BENCHMARK TO USE TO SIMULATE THE POWER CONSUMPTION THAT THE UNIT USES AT THE HOTTEST PART OF THE DAY AND SEER FOR THE COOLER "TAILS" OF THE TEMPERATURE DISTRIBUTION...SIMPLE CONCEPT THAT WENT RIGHT OVER MY HEAD...I WAS THINKING "WHO THE HELL AIR CONDITIONS AT 82 DEGREES (A LITTLE THICK HEADED I GUESS)...I'LL LET YOU KNOW WHAT I HEAR FROM FREUS IN THE NEXT DAY OR SO

BEST REGARDS

KEVIN

OH, FORGOT TO MENTION RE: JOHNSP...THERE ARE 5 HEAT ZONES AND THUS HEATING IS PRETTY EFFICIENT...A/C HAS YOUR TYPICAL 2 ZONE (UP AND DOWN)...

...ONE THING THAT WE CAN DO IS TO ISOLATE THE SOLARIUM ON A THIRD ZONE USING A ZONE DAMPER AS IT'S SUPPLY TRUNK EMERGES FROM THE AIR HANDLER ON IT'S OWN (VERSUS THE SUPPLY TRUNK FOR EVERYTHING ELSE ON THE FIRST FLOOR)...AS YOU CAN IMAGINE, I HAVE TO OVERCOOL THE FIRST FLOOR IN ORDER TO KEEP THE SOLARIUM AT 78 WHILE THE REST OF THE FIRST FLOOR DROPS TO 72 OR 74 DEGREES...WE HAVE ADDED AWNINGS TO THE SOLARIUM WINDOWS DURING THE SUMMER AND THAT HAS HELPED IMMENSELY..

ALSO REGARDING THE TONNAGE FOR THE HOUSE, THE FOLKS THAT INSTALLED THE SYSTEM 14 YEARS AGO DID DO A HEAT/COOLING ANALYSIS AND THE SYSTEM HAS WORKED WELL..WHEN WE NEEDED COOLING POWER ONE SUMMER IN 1993 WHEN TEMPS WERE 100+ FOR THREE OR FOUR DAYS (EXCESSIVE TEMP IN THIS AREA OF THE COUNTRY), THE SYSTEM REALLY DID KICK SOME BUTT. WHEN I SPEAK WITH FOLKS, THEY INDICATE THAT A ROUGH RULE OF THUMB IS 1 TON PER 500 SQ FT OF FLOOR SPACE AND THIS ADMITTEDLY ROUGH MEASURE SEEMS TO WORK..OUR BIGGEST *ITCH HAS BEEN THE POWER AND THAT EVIDENTLY IS A FUNCTION OF 15 CENTS PER KWH AND 9 SEER 7 EER. I CAN'T BLOW UP THE LOCAL POWER PLANT BUT WE WILL CHANGE THE A/C!

BEST REGARDS

KEVIN

[Edited by kevin57 on 03-22-2005 at 10:21 AM]

Undersizing is a bit harder to diagnose conclusively, but if a system can hold your usual indoor temp despite record outdoor heat, it's oversized.

I was hoping you were going to say that your systems really struggled during the heat wave and the house got up to 80 or 81 by the end. They should just barely manage to keep up during the summer. From what you're saying, I'm betting you'll find the old systems are significantly oversized. The only use of talking about "tons per square foot" should be for discussing how efficient or inefficient the structure is. Imposing a rule of thumb because the actual demand of the structure isn't known is just begging for poor results.

So you bet systems run at 82 degree ambients; if they're properly sized, during the hottest few days of summer, and certainly in heat waves, they may run for more than 24 hours nonstop. In the sun belt, they run plenty at night, too, and certainly at 82 degrees ambient (and below).

Oversizing is probably a little bit less problematic if you have a programmable thermostat and actually do use setback periods. If the house is always occupied and always set for the same temperature, though, it's critical to humidity control and efficiency that there isn't any excess capacity.

Heck, here in Georgia, you'll find AC running any time it's not outright chilly outside. We had a March heat wave last week (it hit 78 on Sunday) and lots of people here were running AC... though probably more for dehumidification than for cooling.

Sounds like you do indeed have a tight lot. Geothermal can be done with vertical loops, though, which are dug more like water wells than septic leach fields, so it doesn't have to take much lot space at all. Since you have a good heating setup and are satisfied with the cost to heat the place, though, roughly half of the argument for geothermal goes out the window, and makes it that much harder for such a system to justify its installation cost.

If you are serious about water cooled equ check Geo-Thermal type equ. Also check yith your local Elec supplier for any rebate program the have.

Also consider a ductless mini-split just for the solarium. You're oversizing the whole house system just because of one room with special cooling needs. I would isolate it and cool it with it's own system.

Wow, that's a lot of oil to burn. @ $2/gal , your total AC bills are nothing compared to your heating costs!