my garage heating situation

[FDNYRETIRED]

Hello I did a intro in the intro thread so this is my second post. To get right down to it. I am about to decide what to use to heat my garage and storage space. Which is really going to be a work place. My house was raised due to Sandy and I finally got back in over the summer. Now I am deciding if I should use Modine Hydronic hanging units or Modine hanging Gas units. I have Natural gas. My house walls below the raised section, was built with ICF fox blocks. I have 8 flood vents 4 of which have louvers controlled by bimetal springs. I consider my insulation once I deal with the vents to be a 0.5 if I do not keep opening the garage door. My whole house is pretty tight since it has been almost completely rebuilt.

The garage and Storage Space specs are:
Garage area is 18'x17' with a 13' ceiling. which comes out to 9,113.820 watts that converts to 31,078.125 BTU's. There is also a 6'x17' with a 5' ceiling under the room which use to be on ground level. That is also part of the garage. So for that I come up with 1,168.438 watts that converts to 3,984.375 BTU's. If I add both those up I come up with 35,062.5 BTU's

The Storage space is 26'x19' with a 9' ceiling. For that I come up with 10,186.034 watts which is 34,737.375 BTU's. If I add the Garage and Storage space together. It is 69,799.875 BTUs according to my math. Now the problem is that it is not a total open space between both rooms But it is seperated by Fox Blocks also. With a door that leads to the Garage and the storage space. Then actually what I call the crawl space in the garage also has a wall, But that is only sheetrock on both sides of the studs. There are 2 openings on either side you can get through to get under there. So I really can't put one heating unit in. I need to heat these rooms because the garage contains all my water supply pipes to the house. Also I have a Full pressurized water Fire sprinkler system through the house. With 2 heads in the garage ceiling. and 2 heads in the Storage ceiling.

My idea was to put two Natural Gas 30,000 or 45,000 BTU Hot Dawg heaters, with separated combustion gas ceiling hung units in each room. Then I had a Navien Tech come to help me set up my Outdoor Reset for the Sensor. I have a Navien NCB-240-E Condensing Combi-Boiler. The Boiler runs two zones for the house. Zone one runs most of the house. Zone 2 is actually for a 12' slant fin base board heater for the play room which has a sliding door and the boiler room. It is is Split Level Ranch. All together 4 floors with 3 bedrooms, 2 full baths, Living room, Kitchen and Dining room. Not including the 2 halls.

He says I should run two 50,000 BTU hydronic units off the Navien boiler. Which I thought did make sense. Until I realized that Modine units run at 80% AFUE compared to my boiler which is 95% AFUE when set up right. I am over powered for my house and we cut the Max heating capacity down to 80% for now. I have the Heat load setting set to supply 120-180*f water, and my return is 101-147*F. I am sitting in the 140*F range on return running 2 zones and it went down to 32*F last night around here on Long Island.

So I did a little more research and I think my option if I go with Hydronic units from Modine. Are the Lodronic Low-Temperature Hydronic Heater (HCH) Units. They are $$$ compared to the normal Hydronic units. Then I was looking at the Specs. They make two models:
HHD 30 which with a flow of 5GPM which is what I am set up for from my boiler. Will give me 19,600BTU's @ 120*F water temp to 39,200 BTU's @ 180*F inlet water temp. all at a 405 CFM range. then there is a

HHD 40 which will give me the same at 425 CFM range and 28,400 -56,800 BTU's at a 710CFM range. Then they have a HCH unit with 6 different models depending on BTU's but they are bigger and look like they deal with commercial property. Then they say For conditions other than shown above, please refer to the Modine Breeze® AccuSpec program for detailed performance data.
Allowable water temperature range is 100°F to 200°F. Allowable indoor air temperature range is 40°F to 100°F. If temperatures below freezing are expected, provisions should be made to either
drain the unit heater coil or utilize a continually circulating glycol solution.

I can't do that since it is hooked to my Navien unit. So what would my options be?

 

[mobetta]

you can run a flat plate heat exchanger to add a glycol zone.

it sounds like you should use hydronic in order to get more efficiency out of your Mod Con boiler.

 

[FDNYRETIRED]

I will check into that I am not familiar doing that. But I guess the Hot water from the boiler goes into one loop. Then the other loop gets filled with glycol and the hot water heats the Glycol through the exchanger? If I am figuring this right what pushes the glycol do I have to add a circulating pump to the glycol side including a aqua stat?

 

[nadogail]

IMHO, you will either need a pump or you can try to achieve a thermal siphon flow.

 

[FDNYRETIRED]

Got Ya... I have been talking to people around here with hydronic setups, and they think I am worrying to much about freezing. With the way my house is set up and insulated. They have less insulated houses and garages, and have kept their heaters at 40*F unless working in the garage. They say they get 65*F with out a problem when they turn it up. and that's with less BTU heaters I was thinking of. They tell me I am lucky I don't have a Northside facing garage.

If I have power failure which is my fears. I could run a generator for my boiler. Like I did with the POS Quietside DPW120a I use to have. Plus my frig and a light or two. I know it will be the summer until I have a Generac setup. Once I insulate my flood vents the way I was told to and allow them to be operational incase of another flood. My heat loss will be mostly the garage door. The storage room stays warmer because there is no heat loss except the flood vents and 2 windows 54Lx30W dual pane Argon filled. The windows I have if I need to I can put closed cell insulation board in the frames. I was also told instead of doing 2 separate zones. I could run both rooms off one zone. Keep the thermostat in the Garage and I should get enough heat to flow to the Storage room. I would rather have 2 zones. So that means I will have 4 zones off my Navien NCB 240E. Which happens to be on the floor above my Garage and I will have a downward feed to the heaters. Maybe a 2' drop to the 13' ceiling in the garage and from there another 2' to the 9' storage room ceiling. All these decisions but I am really thinking of the Modine Lodronic HCH 39 or 67 units. Or put a 67 in the garage and a 39 in the storage room.

 

[FDNYRETIRED]

So I am told I will not have to worry about freezing since hot water will always be running through them. Then running each heater off my boiler with separate zones and it will not be a problem. But has anyone ever tried these Modine Lodronic HCH units? I can't find one review on them. Modine is absolutely no help, and has not answered my e mails. Im beginning to think I am over thinking this whole thing. Because I have a Combi Boiler at 95% AFUE and I am trying to match heaters to it. That I might be ok with just 80% AFUE units. Maybe two 50K BTU's. It seems like Modine is the only company that makes low temp hydronic heaters for Condensing Boilers.

If they were so great how come other companies don't make them? Only place I see them is supply warehouse and if I order them it says between Nov 24th to Dec 4. Which isn't a problem waiting if that's true. But do you think I be messing up my AFUE. Maybe having the boiler start cycling instead of modulating. On top of trying to save money. If by going with 80% AFUE units I am not going to have problems I say the Heck with it. Got to make a decision before it gets really cold. I am worried more about the Pressurized wet fire sprinkler system that runs across my garage wall 20', and under the 5' crawl space for 15 ft. Then up to my boiler room where the riser is. Then into my garage ceilings and also through the rest of the house. That water doesn't move. I was even thinking about running heating wire along the pipe in the garage has far has I can, then reinsulate it use it has a back up. I just do not trust heating wires if they break. Eitherway I need to heat the garage so I can use it in the winter