Geothermal HVAC & other heating/cooling Projects - Ferrari Life
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 165 Old 10-06-2010, 07:23 AM Thread Starter
Owner
 
Join Date: Oct 2010
Location: Groton,MA
Ferrari Life Posts: 39
Geothermal HVAC & other heating/cooling Projects

This thread is for discussing state of the art heat pump & similar high-tech heating/cooling projects.

It was prompted by the heat pump discussion started in mk e's V12 conversion thread.
Verell is offline  
Sponsored Links
Advertisement
 
post #2 of 165 Old 10-06-2010, 07:54 AM Thread Starter
Owner
 
Join Date: Oct 2010
Location: Groton,MA
Ferrari Life Posts: 39
Quote:
Originally Posted by bretm View Post
Hey Verell, do you have a detached or an attached garage? Size?

Any more details about the heat pump? Does it have an electric or gas heater as a backup? How warm do you think it'll keep the garage during the winter?

I'm short on shop space, so starting to think about the next step in setting up a larger garage...

Mark, if you want to break this off and keep this thread focused on the 308, maybe it'd be best to start a thread in the Tech Talk section about your geothermal project (per the comments above) and this stuff can life in there?
Bret,
It's attached along 2 walls. Size is 2 bays totaling about 500 sq ft. The heat pump is a Fujitsu 18,000BTU/1.5 ton very high effeciency unit. I wanted the Mitsubishi 14,000 BTU unit, but they were sold out. 18K is slight overkill for 500 sq foot but I'm glad I got it because when we opened up the garage wall to run the refrigerant lines we discovered that the walls weren't insulated( another project - sigh).

The system shouldn't have a problem keeping the garage at about 65F which is what I like for working temp in the winter. Being rated down to 5 F, I shouldn't need backup heat very often. I've been using a propane tank mounted dual burner 24K btu infrared heater that easily kept the garage warm once it was heated up. If it gets too cold I can either use the propane heater, or just wait a day or 2 for warmer weather. If I could have gotten the Mitsubishi unit I wanted, I should never need backup heat.

I'm amazed at how far heat pump technology has evolved in the last 10 years! This unit's SEER rating is 19 & there are Mitsubishi Mr. Slim 12,000 & 14,000 BTU units rated at 23 SEER! If my calculations are correct, I can heat the garage for about 1/4 to 1/3 the cost of the propane I've been buying in 100lb bottles. Would be about 1/2 the cost of the propane I'm heating the rest of the house with.

10 years ago, best you could find was central A/C & heat pump units with SEER of 9 or 10, and window units of 7 to 8.5 or so.

Also, the heat pump break even point on the unit I'm getting is down to 5 degrees F, and it's reasonably efficient at 17 F. Those 23 SEER small units break even at -17F! If I could have waited another year I'm sure I could have gotten a similarly rated 18,000 BTU unit.

Other than AC & heat, the big incentive for installing this year is the 30% tax credit on equipment & installation labor for 2010!!!

Cost including installation was just under $4K before the tax credit.

It's a 'ductless mini-split' system with separate cooling & compressor units(see pix):
Attached Images
   

Last edited by Verell; 10-06-2010 at 08:04 AM.
Verell is offline  
post #3 of 165 Old 10-06-2010, 10:39 AM
Owner
Elite Member
 
cribbj's Avatar
 
Join Date: Apr 2010
Location: Houston
Ferrari Life Posts: 2,197
Most of the areas of Europe and Africa that need A/C use these split units and they really work a treat. The large villas where we lived in Tunisia and Egypt had anywhere from 10 to 12 of them.

IMO they make a lot more sense, and are much more efficient for zone control than using a single large central unit that has no speed/load control, and only manual air distribution control.

The shock load on the home electrical system of multiple small units starting & stopping is also a lot better than a couple of large units.

The downside is that in terms of $/BTU, they're more expensive to install than a couple of big central units, and I don't think they have the life expectancy of a larger central unit.

'99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084

High mileage, low compression, and missing on a few cylinders.....just like my cars.

Maranello Skunkworks Team Member
cribbj is offline  
 
post #4 of 165 Old 10-06-2010, 04:16 PM
Owner
 
Join Date: Jan 2010
Location: york, pa
Ferrari Life Posts: 45
Quote:
Originally Posted by Verell View Post
This thread is for discussing state of the art heat pump & similar high-tech heating/cooling projects.

It was prompted by the heat pump discussion started in mk e's V12 conversion thread.
Hey Verell, good to have you over at "the life."
Great thread topic. I'm tuned in and ready to learn.

Spang
spang308 is offline  
post #5 of 165 Old 10-06-2010, 04:24 PM Thread Starter
Owner
 
Join Date: Oct 2010
Location: Groton,MA
Ferrari Life Posts: 39
I'm not sure of the $/BTU advantage of large central over mini-splits. The central units require source & return insulated ductiong that isn't cheap to install. Also the central units are either on or off everywhere. (By 'large units' I'm thinking in terms of residential central air units. When you get into central units for commercial buildings the story may change. A lot of the building units willl have a central compressor feeding multiple blower/heat exchangers that have their own thermostats. In some ways similar to a multiple head mini-split except that everything's concealed inside the walls & ceilings.)

As for reliability, my HVAC supplier said that it's reasonable to expect 20 years out of a system, about the same as a central system.

About 10 years ago we installed 2 systems, a central system for the 1st floor that used existing forced hot air source & return ducting. And a 3 head Mitsubishi Mr. Slim heat pump for the 2nd floor. So far the only problem either has had is the Mr Slim unit ran a bit low on coolant this summer & had to have a pound added. Even 10 years ago the Mr. Slim was a leader in efficiency. Like my garage unit it has an inverter powered fan & compressor, so varies their speed based on head unit demand.

What's really nice is I can run any combination of 1 to 3 of the head units. We often only run one to heat or cool the master bedroom. Also, each head unit has it's own temperature setting & sensing.
Verell is offline  
post #6 of 165 Old 10-06-2010, 06:07 PM
Owner
 
mk e's Avatar
 
Join Date: Jun 2010
Location: PA, USA
Ferrari Life Posts: 4,439
Here's the start of my geo system. I have a couple acres and I知 not afraid to (try) to run heavy equipment so I'm doing a closed loop system horizontal system, which means I知 going to bury a whole lot of pipe 6-8 ft deep in my yard. The other option is a vertical system where the pipe goes in a well or series of well that are about 150 ft deep for every 1 ton (12000BTU) of system capacity. It a horizontal system the number can carry quite a bit depending on a whole lot of variables, but my area where there is a decent amount of water in the ground and the soil is clay and using pipe in slinky like coils I need to dig 3ft wide x 6-8ft deep x about 100 feet long for every ton. I知 installing 6 tons so 600 ft of trench is required.

I知 planning to go 800 ft to add some safely factor. I know, you池e saying but Mark why?. Well there is a dirty little secret about geo systems I stumbled on and I知 trying to compensate for it a bit. A geo system is really just a heat pump like Verell was talking about. For those who don稚 know, a heat pump is quite literally an air conditioner running backwards vai a reversing valve so instead of talking heat from inside and putting it outside like an AC system it takes the heat from outside and puts it inside..air conditioning the outside if you like. Because the heat system is the AC system running backwards it has pretty much exactly the same system output normally.so 1 ton (12kBTU) of AC gets you 12kBTU of heat. Where I live it hits 100F in the summer and we keep the house at about 75F. so a 25F difference which is currently handled by 2 2.5 Ton (30kBTU) AC units. In the winter it get down to say 25F pretty regularly and could go as low a 0F. So, normal heat requirement is a 50F difference or double the cooling load..now it痴 not truly double because there is a lot of heat adding things like lights, cooking, the sun that add to the cooling load and decrease the true heating load leaving the heating load about 6.5 to 7 ton for my house. Notice that 7 is not 5 and that痴 a problem. You want to err on the high side with heat to handle to worst conditions but with AC you really want to err on the low side or the system will not be able to properly pull water out of the crazy humid summer air.we have a problem.

With standard heat pumps the solution is a 2 speed compressor. On the low the unit ia at peak efficiency and produces about 2/3 rated capacity and this is the normal operation mode. Then when needed it kicks into high V AC issue. They also add an auxiliary electri heater to cover the very coldest days giving you 2 stages of AC and 3 stages of heat. Great! .but things change a little with Geo. The geo systems generally do exactly what the standard heat pumps do with equal heating and cooling when they are running in an open loop system (well water comes in and is discharged to a pond or stream) but almost no one has an open loop system. In closed loop the circulating water gets warm in the summer and cold in the winter and the extra heating load mean the water gets cold and that decreases the unit痴 output. The net effect is that a 1ton AC unit give about セ ton of heat and also the 2 speed compressor is less effective making the low speed about 75% of the high..so the heat on high is about equal to the AC on low. This means while the system is more efficient than a normal heat pump (think seer 27-30), you either have to oversize your AC to get enough heat, or you have to run the aux heat a low more or the time. I知 going a bit big on my ground loop to help reduce the heat lose issue and sizing to have low speed almost exactly equal my current 5T AC system, this mean the aux heat will definitely run on cold days, but it痴 only to make up the last few BTUs so most of my heat will be geo and honestly, electric heat is only about 10%-20% more than my current propane so even with the aux heat full blast it痴 still nets out WAY cheaper than running all propane.

I bought 6400ft of pipe and statred making up the loops and they are dropping off an 8 ton excavator Friday the 15th.and let the digging begin
Attached Images
       
mk e is offline  
post #7 of 165 Old 10-06-2010, 06:14 PM
Owner
 
mk e's Avatar
 
Join Date: Jun 2010
Location: PA, USA
Ferrari Life Posts: 4,439
Quote:
Originally Posted by cribbj View Post
Most of the areas of Europe and Africa that need A/C use these split units and they really work a treat. The large villas where we lived in Tunisia and Egypt had anywhere from 10 to 12 of them.

IMO they make a lot more sense, and are much more efficient for zone control than using a single large central unit that has no speed/load control, and only manual air distribution control.

The shock load on the home electrical system of multiple small units starting & stopping is also a lot better than a couple of large units.

The downside is that in terms of $/BTU, they're more expensive to install than a couple of big central units, and I don't think they have the life expectancy of a larger central unit.
Zoning is a good think for sure. The standard by code here in the US is at least 2 zones on larger houses and multi-speed compressors and variable speed fans are becoming the standard.

There are also really nice zone control systems available that can control each room separately....I'll add one of these if the money holds out but I dont' think it will I think to reto fit my house with 9 rooms and about 21 duct outlets and deal with 2 2-speed air handlers I'd be looking at around $3500 in parts.
mk e is offline  
post #8 of 165 Old 10-06-2010, 06:22 PM
Owner
 
bretm's Avatar
 
Join Date: May 2002
Location: New Jersey
Ferrari Life Posts: 2,152
Quote:
Originally Posted by Verell View Post
...The system shouldn't have a problem keeping the garage at about 65F ...
65F during the winter... I'm jealous. My (unheated) basement goes down to around 45F and the garage goes down to around 30F! It's certainly not fun turning wrenches in either setting, even with a little spacer heater going.

I hadn't really paid much attention to air pumps prior to Mark starting his project, and now seeing yours here. It's very interesting stuff.

I think that realistically I'm going to have to think about building a detached garage over the next few years. It'd be nice to not have to run a gas line out to it from the house and lose floorspace to a furnace and radiators. Definitely some stuff to think about.
bretm is offline  
post #9 of 165 Old 10-06-2010, 06:48 PM
Owner
 
bretm's Avatar
 
Join Date: May 2002
Location: New Jersey
Ferrari Life Posts: 2,152
Quote:
Originally Posted by mk e View Post
...I bought 6400ft of pipe and statred making up the loops and they are dropping off an 8 ton excavator Friday the 15th.and let the digging begin
Probably only your next door neighbors knew you were crazy from seeing the blue welding light coming out of the basement every night. With this project though, I'm pretty sure the whole neighborhood now knows.

On another topic, it's a pretty cool setup having a normal garage up by your driveway, and then the ability to put the 308 into the basement. It's nice keeping the endless aluminum chips from the mill away from the rest of the high-traffic areas.
bretm is offline  
post #10 of 165 Old 10-06-2010, 06:57 PM
Owner
 
KKRace's Avatar
 
Join Date: Nov 2009
Location: Near Olney, MD
Ferrari Life Posts: 1,354
I have a 75K BTU unit heater mounted to the ceiling so I don't lose any floor space or have to install any duct work. I thought about a heat pump but I leave the heat set at 45 degrees unless I'm out there working. When I turn on the unit heater the temp comes up to a comfortable temp in about 15 minutes. Warm air is blowing on me within two minutes. If I tried that with a heat pump it would take hours to raise the temp.

If you plan on just leaving the heat set at something like 68 degrees all the time then a heat pump is probably a better option.

The LP gas unit heater cost me about $700 and I just needed to install a short section of 4" B-Pipe vent. My garage is 1100 sq ft and 75K BTU does a nice job. The unit heater I bought was for low ceilings and only hangs down 16 inches.

------------------------------

Life is Good!

Last edited by KKRace; 10-06-2010 at 07:27 PM.
KKRace is offline  
post #11 of 165 Old 10-06-2010, 07:02 PM
Owner
 
KKRace's Avatar
 
Join Date: Nov 2009
Location: Near Olney, MD
Ferrari Life Posts: 1,354
Mark, I heard you can run the pipe every three feet of dirt. Meaning you could run 3 layers of pipe in a 8 ft deep trench by putting in the first layer of pipe then covering with 3ft of dirt and then another section of pipe etc?

------------------------------

Life is Good!
KKRace is offline  
post #12 of 165 Old 10-07-2010, 02:53 AM
Owner
 
mk e's Avatar
 
Join Date: Jun 2010
Location: PA, USA
Ferrari Life Posts: 4,439
Quote:
Originally Posted by KKRace View Post
Mark, I heard you can run the pipe every three feet of dirt. Meaning you could run 3 layers of pipe in a 8 ft deep trench by putting in the first layer of pipe then covering with 3ft of dirt and then another section of pipe etc?
That's a yes and no. When you run straight non-coiled pipe it makes a whole lot less contact with the ground so the standard is to run a couple pipes per12" wide x 6ft deep trench, put in t about 2 ft of fill then run the pipes back in the same trench giving you 4 or even 6. These trenches would be no less than 5 ft apart. With the slinkyed pipe most of the heat that can be gotten is so while you can put another loop a couple ft above, it doesn't add much to system effectivenss. Another think to keep in mind is that the ground temp at 30ft deep and deeper is a constant 55F around here, but as you get closer to the sureface the temp varies more and more until you get to the surface and the temp basicaly equals the air temp. At 5ft deep the ground temp varies about +/-10F with about a 2-3 month lag so the ground is warmest in the fall and coldest in the spring. At 10ft deep the variation is +/-5F so there is a real advantage to going deeper but a trench any deeper than 6ft is not safe to be in for any reason (trenches do cave in and you would want at least your head out when that happens) so caution is required as the trench gets deeper.

I will be dropping the loops in at as close to 8ft as the rocks will allow then fillat least 2 ft and send the feed pipe (straight section to get to the end of the slinky) well away from the returning warm lines. Becasue it's a DIY effort the digging part is pretty cheap so going the little extra doesn't really add any cost but will make it work better.
mk e is offline  
post #13 of 165 Old 10-07-2010, 05:28 AM
Owner
Elite Member
 
cribbj's Avatar
 
Join Date: Apr 2010
Location: Houston
Ferrari Life Posts: 2,197
Mark I'm sure you've already done the due diligence on these, but here in TX, the geo installers weren't getting the A/C capacity they needed during the peak of the season because the ground thermal conductivity was higher than anticipated. (This was with the multiple vertical borehole systems.)

The result was that they had to increase the horizontal spacing of the boreholes, which didn't help the existing customers who weren't getting the cooling they needed in July/August. Those poor folks have had to add supplemental capacity by using splits or small supplemental coil/condenser central units.

Not much comfort when you've just paid out close to 1.5x what a conventional system would cost, then have to fork out even more because it's underperforming. Talk about getting hot under the collar for more reasons than one......

'99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084

High mileage, low compression, and missing on a few cylinders.....just like my cars.

Maranello Skunkworks Team Member
cribbj is offline  
post #14 of 165 Old 10-07-2010, 06:16 AM
Owner
 
mk e's Avatar
 
Join Date: Jun 2010
Location: PA, USA
Ferrari Life Posts: 4,439
Quote:
Originally Posted by cribbj View Post
Mark I'm sure you've already done the due diligence on these, but here in TX, the geo installers weren't getting the A/C capacity they needed during the peak of the season because the ground thermal conductivity was higher than anticipated. (This was with the multiple vertical borehole systems.)

The result was that they had to increase the horizontal spacing of the boreholes, which didn't help the existing customers who weren't getting the cooling they needed in July/August. Those poor folks have had to add supplemental capacity by using splits or small supplemental coil/condenser central units.

Not much comfort when you've just paid out close to 1.5x what a conventional system would cost, then have to fork out even more because it's underperforming. Talk about getting hot under the collar for more reasons than one......
Yeah, ground temp changes can a big issue particularly with big commercial systems. I read it takes about 10 years for the ground temps and corresponding system performance to stabilize.

For a normal size house in this area they normally only drill 1 well so that eliminates the chance that the spacing will be a problem. Spacing is a major concern with the horizontal systems like I知 doing though. My local electric company has published guidelines for this area which I followed (trenches will be 10ft on centers) and added 50% to the total length for good measure so I知 pretty sure there won稚 be a problem with over-heating or cooling the ground itself. Also here it痴 the heating load that dominates and there is auxiliary electric to supplement thatwhich I知 also building in a pretty large margin on. I should need about 12000-15000 BTU which is about 3.5-5kW of electric. I知 installing 2 heaters, one on each air handler, that each have a 5kW and 10kw element that are on separate breakers so they can be 5, 10, or 15 kW giving me up to an additional 30kW or 100kBtu, which should be enough to more than handle all my heating needs all by itself should the need arise.

The big issue here seems to be companies trying to give the home owner the best return on investment an that means sizing the system to handle all the heating loadswhich means it痴 WAY oversize on the AC side. A neighbor has a system like this and it loses control of temps for about 3 weeks in the spring and fall when only a little AC is needed. The installer told him that痴 normal with Geo systems because the air temp is too close to the ground tempwhich is bullshit. The problem is the AC system gets the on signal from the thermostat and kicks on, cooling the house to the desired temp in about 3 minutes flat, but the system has a minimum run time or about 15-20 minutes to prevent the compressor form stopping and starting too much which uses a lot of power and is bad for the compressor.and after 20 minutes the system has dropped the house temp well below the set point.

Mostly it seems the guys doing stuff like this don稚 realize how much they are over sizing because geo system don稚 act exactly like normal heat pumps. Normally when you see a 3T rating that is heating and cooling because the temp difference the heatpump sees is exactly the temp difference the house sees.but that is not true on geo systems that have a 田onstant 55F sink they work with. This mean when the AC is running the unit it pumping heat in the direction the heat wants to go with a 75F house and 55F souce/sink and the AC works good. For heating though there is a 20f delta the system is working against so the output is lower. The manufactures seem to mostly rat the unit by heat output in an open loop system so a 1t rating gives 1T or heat and 1.2T or so of cooling. When they go closed loop the heating output drops a more than the cooling output and you get something like 1.1T AC and .75T or heat. My neighbor has a 7T system, so he痴 getting about 7.7T or AC when he actually needs less than 5T. The installers then fall back to the 2/3 rule where low is 2/3 of high..on a standard heatpump but more like .75 on a geo unit so while they think they gave him about 4.7T of AC on low he actually gets about 5.8 midsummer and more like 6.3 in the spring when the ground is at its coldest and the AC performance at its best. With geo you really need to look at the graphs for the particular unit you are thinking about rather than trust the size rating and the general rules or problems will almost certainly follow.
mk e is offline  
post #15 of 165 Old 10-08-2010, 07:13 AM Thread Starter
Owner
 
Join Date: Oct 2010
Location: Groton,MA
Ferrari Life Posts: 39
Quote:
Originally Posted by mk_e
This means while the system is more efficient than a normal heat pump (think seer 27-30), you either have to oversize your AC to get enough heat, or you have to run the aux heat a low more or the time.
WOW! I hadn't realized that geothermal SEERs were so much better than air exchange heat pumps. Or is this the SEER for your near dual speed pump?

Have inverter variable speed pumps appeared in the geothermal space? They have the obvious advantage of infinitely variable speeds, so can match coolant flow closely to demand. This is a major contributor to the efficiency of my mini-split air-air heat pumps.
Verell is offline  
post #16 of 165 Old 10-08-2010, 07:32 AM Thread Starter
Owner
 
Join Date: Oct 2010
Location: Groton,MA
Ferrari Life Posts: 39
Quote:
Originally Posted by KKRace View Post
I have a 75K BTU unit heater mounted to the ceiling so I don't lose any floor space or have to install any duct work.
I needed both AC & heat. Looked at several options. Plumbers wanted $1500 - $1800 to run propane up to the garage ceiling area , & a high efficiency 75K BTU tube type infrared heater was about $1K. Cheapest A/C option would have been to mount a large window unit up high on the wall. The system price would have ended up pretty close to what this one cost after the tax credit, and wouldn't have had the heat pump's energy cost savings.

Quote:
Originally Posted by bretm View Post
65F during the winter... I'm jealous. My (unheated) basement goes down to around 45F and the garage goes down to around 30F! It's certainly not fun turning wrenches in either setting, even with a little spacer heater going.
BEEN THERE!

Cheap interim solution is a 25K to 30K BTU infrared propane heater. Mr. Heater makes a variable heat dual burner one that you can run one or both burners & low/med/high gas flow to select from about 6K BTUs to 24K btus. They're made for mounting on 20 lb tanks, but work just fine on 100lb tanks which gets them up to a nice height for distributing the heat. You'll have to rig up a simple mounting bracket for the 100lb tank. It will bring your garage up to temp in a couple of hours altho the floor will still be cold until the slab absorbs enough heat to warm it up. Nice thing about infrared is it's like a light, warms whatevers in front of it, so you can actually be comfortable in a cold room. I once had to work on a car in a parking lot in 5F weather & one of these heaters kept me warm enough so that I pulled my jacket off!

I started using the infrared propane heaters when I started spending lots of time in the garage. However, I would go thru a 100lb cylinder in about a week in the coldest weather.

My current thinking is that I'll probably heat the garage to about 55, and only bring it up to the low 60s when I"ll be working in there for several hours at a time. 55 is pretty comfortable when just working an hour or so at a time with long sleeves on.

It's going to be interesting to see how fast the system can change the garage's temperature. With a car, my machine tools, the 'stuff' stored there, & the floor slab there's a large mass to heat up. On the other hand, once the temperature is stabiliized it has very little fluctuation.

A couple of times this summer I had the garage cooled down & stepped outside leaving the small door under the compresssor open so I could bring something in. Usually the comporessor fan was barely turning over. Then as warm air came in the fan would start running faster & faster.

Last edited by Verell; 10-08-2010 at 07:45 AM.
Verell is offline  
post #17 of 165 Old 10-08-2010, 08:24 AM
Owner
 
mk e's Avatar
 
Join Date: Jun 2010
Location: PA, USA
Ferrari Life Posts: 4,439
Quote:
Originally Posted by Verell View Post
WOW! I hadn't realized that geothermal SEERs were so much better than air exchange heat pumps. Or is this the SEER for your near dual speed pump?

Have inverter variable speed pumps appeared in the geothermal space? They have the obvious advantage of infinitely variable speeds, so can match coolant flow closely to demand. This is a major contributor to the efficiency of my mini-split air-air heat pumps.
Careful, I said think SEER 27-30.Geo units are EER rate which is a slightly different standard but the basics are the same BTU output/1kW input. The units are more efficient running on low speed, which they do most (80%+) or the time. I think they lose about 25% efficiency on hi speed.

The real thing you want to see is a COP vs outside temp chart to look at the 2 systems. Air/Air unit performance is a direct function or the outside air temp so the SEER number is only true under 1 set of basically ideal conditions and that痴 what leads to the 澱reak-even point you were talking about where the COP (KW out/KW in)=1 as it gets very cold outside. Geo units have a basically constant sink temp so the COP is the COP regardless of outside temps and 1kW in get you about 4-5 kW out always. Air-Air units would win on heating in the spring and fall when the outside temp is above about 60F but you tend not to need much if any heat under those conditions. The Geo units win everywhere else for heat and always win on AC (unless you wanted to AC your house when the outside temp was below 55F) because of the basic math which al involves the sink/source temp. The Geo units basically use most of the same part the air/air units use with the only difference being 1 water/air heat exchanger replaces the air/air heat exchanger that would go outside on an air/air unit, everything else is exactly the same, it just comes down to the sink/source temp

I haven稚 seen any variable speed pumps. This probably wouldn稚 work out very well since slowing the pump would allow the flow to become laminar and it doesn稚 do a very good job transferring heat when that happens. In my system I知 using 4 parallel loops per heatpump so I opted to go up to a 2 pump unit normally used on 4-5T systems even though 1 pump had enough flow to support my 3T unit.but the 4th loop would slow the flow down very close to the laminar transition. I値l probably go ahead and look at loop temps with 1 and 2 pumps running and see if the second pump is truly required or maybe tie it to the units hi/low speedbut I知 planning to need both pumps anytime the unit is on.

The geo units (and all the better air/air units) do use a variable speed fan on the air circulation which is nice for both saving energy and makes the house more comfortable by only blowing the air that is needed. It also makes them work really well with zoning systems if I ever get that far. Better units (both geo and air) also use unloading compressors which drops start-up loads significantly saving more energy.
mk e is offline  
post #18 of 165 Old 10-08-2010, 10:19 AM
Owner
 
bretm's Avatar
 
Join Date: May 2002
Location: New Jersey
Ferrari Life Posts: 2,152
Quote:
Originally Posted by KKRace View Post
I have a 75K BTU unit heater mounted to the ceiling so I don't lose any floor space or have to install any duct work...
Quote:
Originally Posted by Verell View Post
...BEEN THERE! Cheap interim solution is a 25K to 30K BTU infrared propane heater...
Apparently I've been living in the stone age. I think you guys might be onto something. I was just going through a number of websites, and 10-20k BTU infrared heaters are pretty inexpensive. That might make a nice interim solution until I can move on to a bigger and better space.

Do infrared heaters burn a high % of the oxygen in the room? It looks like most of them don't require venting.

My only experience with propane heating is a convection heater that we used to use on jobsites. It soundes like a jet engine when running at full tilt, and would no doubt kill you within an hour if run inside.
bretm is offline  
post #19 of 165 Old 10-08-2010, 11:14 AM
Owner
 
mk e's Avatar
 
Join Date: Jun 2010
Location: PA, USA
Ferrari Life Posts: 4,439
Quote:
Originally Posted by bretm View Post
Apparently I've been living in the stone age. I think you guys might be onto something. I was just going through a number of websites, and 10-20k BTU infrared heaters are pretty inexpensive. That might make a nice interim solution until I can move on to a bigger and better space.

Do infrared heaters burn a high % of the oxygen in the room? It looks like most of them don't require venting.

My only experience with propane heating is a convection heater that we used to use on jobsites. It soundes like a jet engine when running at full tilt, and would no doubt kill you within an hour if run inside.
The oxygen shouldn稚 be a problem in a garage, but water can be. Propane, C3H6 makes 2 waters for every molecule you burn and that will make the garage humid and that humidity will condense out onto anything cold.like the car. I always used the wick type kerosene heaters but they have that kerosene small about them and no type of portable heater is supposed to be left unattended. A mounted and vented heater is a much better solution even if it does cost a little more I think.
mk e is offline  
post #20 of 165 Old 10-08-2010, 12:34 PM
Owner
 
KKRace's Avatar
 
Join Date: Nov 2009
Location: Near Olney, MD
Ferrari Life Posts: 1,354
Quote:
Originally Posted by Verell View Post
I needed both AC & heat. Looked at several options. Plumbers wanted $1500 - $1800 to run propane up to the garage ceiling area , & a high efficiency 75K BTU tube type infrared heater was about $1K. Cheapest A/C option would have been to mount a large window unit up high on the wall. The system price would have ended up pretty close to what this one cost after the tax credit, and wouldn't have had the heat pump's energy cost savings.

.
I just had a propane company drop a 100 gallon propane tank behind the garage and ran 1/2 inch copper line for about 20 feet to the unit heater. The propane company included the regulator and the tank for free if I buy gas from them(Don't hook propane tank up to the heater without the regulator!!!).

The unit heater is nice becuase it blows warm air and heats the garage fast. It's mounted up against the ceiling and takes no floor space and you can either vent it out the roof or out the side of the garage if the unit is withing four feet of a exterior wall. The vent is double walled 3" B-pipe which is easy to install. Just snap together parts. If you decide to add a heat pump later just have the installer wire your unit heater up as the emergency heat. That way you would only have one thermostat.

The floor and tools are still cold. I keep some rubber mats or wood to stand on when I'm working and that takes care of the floor problem. The cold tooling hasn't been much of an issue since I don't let the garage get colder than 45F.




...and yes I know the romex wire should be in conduit to meet code but I got lazy and it doesn't draw many amps to run the thing. Everything else is up to code.
Attached Images
   

------------------------------

Life is Good!
KKRace is offline  
Reply

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
Copyright 2012 ONE Media, Inc.
FerrariLife is independently run with no affiliation with Ferrari SpA
Ferrari for Sale | Maserati for Sale