heat source hold back

Brooksi

would like to thank for help in my last thread.

Still struggling and getting late in what heat source to use in my pex tubing radiant floor. My problem is we eliminated the crawl space portion of the house, added tubing and poured concrete. I am using one 4 loop manifold to supply the infloor concrete portion with 2- 150' loops and in the remaining area floor joist heating with 2 - 150' loops = 600' total for a bungalow of 700 sq ft . Understanding the concrete should only be between 90-100 f, in the floor joist portion i will styrofoam insulate the bottom between the joist to compensate for the lack of 160 f heat it suggests. In the joist area the basement portion is only 5' tall so believe a tankless is what is needed yet the suggestions im getting are too expensive and having installed out of the question.

Does it make any sense using 1 or 2 electric closed water heaters set to run mostly at night during low peak hrs or is there a simple gas tankless low cost system I can buy like from home depot. If so need to know the size of heater. There is gas supply pipe near the area by the outside wall, electricity and water drain. in addition need to know what size circulating pump needed to run this small system knowing i need expansion tank etc yet am looking at completely simple system. It still has the forced air furnace (duct work removed) as back up in the case I am wrong yet would like to stick with radiant and be a hero yet am failing at the moment due to cost (she is not happy).



Desperate moments in need of a hero.

SWEI

Back up just a bit

did anyone perform a room-by-room heat loss calculation?  That is step one.  From that, the tube spacing and slab/floor construction will lead to a design water temperature (the water temperature needed to heat the house on the coldest day of a typical winter.)  From that, one can determine how many GPM at what temperature is needed for each area and a system can be designed.



How is the tubing fastened to the floor between the joists?  Do you still have access to it?



Water heaters are not suitable for this application.  Search The Wall and you will find plenty of sad stories on the topic.  Electric hydronic boilers are relatively inexpensive to purchase or to install, but generally cost quite a bit to run.  Depending on the building design, solar orientation, and location that may still be your best choice.



Be patient -- this will take a bit of work but it is absolutely worth your time.

Brooksi

Im under the gun, so I wish I could back up a bit. like to september..lol

thanks for your reply

this all came about with my buddy putting in his garage a simple system himself and then another friend also in his garage which works great. So unfortunately no there was no design heat loss evaluation. He used a propane water heater tank. Understanding his is a garage i knew I would have to do things a bit different yet as you said i dont want to be one of those sad story post, any more than i am.



We attached the tubing to the joist floor with plastic clips and then used pop cans stapled to the under floor to hold up in between clip spaces also as deflectors of the heat. Yes we still have access. Can I use an electric water heater like a 60g to start and then incorporate a solar system to help it or should i look right into solar. there are renters moving in friday so im thinking as much as i hate the temporary failure in this ill have to do some duct work, reopen holes in the floor and hook up the old forced air furnace again.



I can work on this 24 hrs a day to get it done, i can turn my hand at anything, the only thing holding me back is the system to use and the money which i have about 2500 to use, possibly a bit more. any help wold be great.

Brooksi

it is just a little 750 sq ft bungalow

I have been listening to so many different ideas and people trying to find the happy medium between the guys who want you to have every gauge and sensor as if it was part of Nasa's space shuttle and cost as much, to my buddy's propane expansion tank ball valved redneck system that he had to turn down because his feet would sweat to much in his work boots. Worst part is most people thought i was nuts going this route, and the girl im doing this with is beginning to loose faith. I know im out there, just dont want her to have to listen to the people saying, I told you so...... so a firm economical direction would be my out.

SWEI

Begin at the beginning

we really do need a bit of information before we can even get started here.  Bear with me, it will be worth the effort.



The heat loss calculation is not optional.  Do you have access to an iPhone, iPad, or Android?  http://www.slantfin.com/index.php/homeowners/ipadapp will help a lot.  If not, there are others online.



What energy options do you have available there and what do they cost?  Is the space going to be continuously occupied, or just occasionally?  Where is it located?

Brooksi

thanks

i have an iphone, not exactly a sherlock holmes by any means but i have one. you will have to elaborate on the websight and how it helps.



energy options are many. cash is not due to money spent on renovations to entire house.heat source is now the last component. the house was purchased as a fixer upper. I can purchase a mini boiler for 2500$ yet it needs to be a simple system and not sure how boilers work. it has gas to the existing forced air furnace



the front one bedroom apt portion of the house is rented out and the owner is living in a one room concept with a bathroom in back to afford the mortgage on her low income.



it is located in ontario minutes from lake ontario in town east of toronto so not desperately cold for any length of time.

SWEI

Slant/Fin heat loss app

Open up the iTunes store in your iPhone and search for "slant/fin" and it will pop right up.

Brooksi

k so i down loaded the app

not exactly sure how it works

Brooksi

im guessing i need exact measurements of each room

so im going to head there now and get those calculations

Brooksi

so i have the app yet im not getting how you add the info

k so i just cant figure out this app. i even tried googling how to input info and im not getting it. i have the info. just am confused how to negotiate through it.

SWEI

Heat loss app

First you enter a job name, then floors, then rooms.  Inside each room you enter length, width, height, and U-values (they call these Factors.)  Anything with a > next to it has a list you can choose from.  Each room also has an indoor temp and an outdoor temp.  Look up your outdoor design temp online (use the ASHRAE 97.5% data if given a choice.)  Indoor temp for radiant is generally 3ºF lower than for forced error, so we use 65ºF (72ºF for bathrooms.)  The summary items will show a red zero next to them when you first begin.  As you populate data, the numbers will start to total up.

Brooksi

heat loss cal.

the calculations i get if correct is for indoor temp 72. outdoor -6 . water temp 180. btu/hr 468. i did not know how to add factors or cold portion info.

Brooksi

thanks

because im new at this i replied to a previous statement of yours with what i could figure. I will try to add in the additional info from your suggestions and reply asap

Brooksi

almost complete

did not get the cold portion submitted for i do not know what part of the hse they are referring to. the ashrae 97.5 % also cannot find. I have submitted all other info. So what i have so far is a reading of;



indoor temp 65f.

outdoor ; -6 f

water temp ; 180f (yet understand concrete can only be between 90-100F ?)



BTU/ Hr ; 21438

SWEI

Toronto

I'm seeing 1ºF using ASHRAE 99% data, which is even more conservative.



Don't worry about fluid temp in the Slatn/Fin app -- they're mostly trying to sell baseboard with it.  We try to live with an 85ºF surface temperature limit on radiant floors.  The water temp needed for that depends on the construction and piping details.  Next step would be to drill down to the tube spacing, plates, etc. which will determine the water temp needed for each room or zone.



21,000 BTUs per hour is smaller than any modulating condensing boiler available today.  It's about twice the minimum firing rate of the smallest models we can get.  A small electric boiler is the least expensive (first cost) method of delivering comfort.  http://www.thermolec.com/en/productView.aspx?type=product&id=62 comes with built-in outdoor reset control and is quite affordable.  The 6 kW version should work just fine.



http://www.eia.gov/neic/experts/heatcalc.xls will help you understand the real costs of energy.  Plug in your fuel costs, change gas boiler to 95% for a mod/con and see where you fall.  The smallest mod/con currently available is going to cost roughly 3x what the Thermolec will, and the installation could easily be 4x on that depending on venting and gas pipe locations.

Brooksi

thanks, next step?

drill down to tube spacing,? can you elaborate on that.



im hoping the electric boiler is the answer yet she is only running a 100 amp fuse panel service at the moment, so do you know if an electric boiler can run off a 15-20 amp fuse or what it needs.



the website for understanding cost of energy i am not sure what that intales yet will fumble my way through it.



i appoligize for my lack of knowledge in all this, as i said i got the idea from a redneck version in a garage of my buddy. your info has given me knew hope that this is doable. the installer i have been talking to is advising me to cut my loses and stick with the forced air system saying that the concrete tubing loops at 10-12 " apart is insufficient.



i have a four loop manifold. 1 in concrete with loops10-12" apart of 150' run in a 170 sq' room and another 150' of 160 sq' in concrete

the other two loops go in floor joists at 340 sq ' above the basement which the two concrete floors skirt the outside a good portion of the back and side of the joist room and i intend to insulate between the joist down a couple inches from the pex with styrofoam to compensate for the low heat that supplies the concrete. (my understanding joist heating is suppose to be closer to 160 f) . it is just a little house.



I will check out the website for the electric boiler and if any other insight i would again greatly appreciate.



I must go hook up some of the duct work as it is looking this is going to take some time before i am heating with radiant.



again thanks and any additional help i could still use it.

Brooksi

thermolec TMB electric boiler 6 kW

i am waiting to hear back from this company they have a distributer in ontario.

SWEI

Thermolec TMB-6

Draws 25A maximum (at 240V.)  Should be no problem with a 100A service.



By drill down I mean model the heat transfer capacity of your emitter system (aka the tubing.)  Do you have any photos of the tubing and the beer cans?  What spacing was it installed at?



You may be able to get the upper floor working with 100ºF water by using 8" spacing and adding commercial heat transfer plates.

Brooksi

tmb6 uses a 40 amp breaker

so along with pricing i will have to find out from the company what size wire i need to supply it. hopefully today.



yes i do have photos (ill figure out how to get from iphone to here) of the tubing. the hole job was laid out on a 10"-12" space basis some even closer to 8" in the joist area. the cans are an on going process only a few at this time and will be adding more as we go as i am understanding we cant have to many. yet only a few beer cans as they can go back to the beer store to help buy more beer, pop cans are the material of choice.



we have talked about tieing the 2 150' loops in the joist area together and adding another 300' loop to get closer to 6" spacing in that area yet concerned the affect that would have being twice as long loop as the other concrete sections of 150 each although could tie those loops together also creating a 300 loop system for all loops yet that again compromises one of those areas in the concrete as one entire room would only be fed at the end of the loop. . The house is a bungalow so the joist portion is (above the 5' basement area) and the same level as the concrete area. The house had a crawl space under a potion of the house we tore up and added a concrete floor .



I have seen the commercial transfer plates and will keep those in mind.



sorry for the delay somehow i did not see your reply above mine and just noticed it this morning.



I will get pics when figure out how.



thanks again