best cooling method for radiant heated building?

[Legwound]

I'm in the investigative stages for a house/shop build that will be enclosed in a single building.

Im looking very closely at radiant in floor slab for the ground floor and radiant in floor (possibly warmboard.com product) for the second floor living space.

Heat inputs are still up for grabs but there will be a solar component with some supplimental. The building will be spray foamed.

Anyway, to my question; what would be the best way to cool this type of building?

Can I use the radiant system to cool as well. Is this comfortable, would I have condesation/mould issues?

I'd prefer to not have to install some form of forced air cooling, but i'm just starting to think of the cooling aspects.

I did do some searching of the forum but didn't find much. Admittedly my searching skills ****.

 

[pseudorealityx]

You can do radiant cooling, but it typically requires some pretty precise control to avoid condensation as any cold surface below dew point will start to condense. Obviously that also limits how cold you can go, and it won't do a thing for humidity.

Heating is 'easy' to do via radiant... all you're doing is adding energy into your box. Cooling is harder, as you have to physically REMOVE energy from the system.

 

[Denwood]

Regardless of heat type, new construction still requires HRV (fresh air), and if cooling, likely an air handler with AC. Cooling with radiant is generally not done due to condensation issues.

Depending on cooling needs, split AC zoned units are very efficient, and pretty common where energy costs are higher. I'll probably ruffle a few feathers here, but if you insulate your slab and building envelope well, radiant heat may not actually be the most effective use of your dollars as you still need to exchange fresh air, and also cool/dehumidify. My business uses a combination of radiant (main floor, 5000 sq.ft, 4 zones) and hot water/air handler upstairs. We had to have 5 air handlers (with an acoustically isolated studio system) regardless of the radiant heat to ensure fresh and cool air during summer months. Doing it again, I would have insulated the slab very well, but nixed the radiant. It would likely have been just as efficient, but a lot less expensive. With a very efficient envelope, we can't have the slab much more than 68F anyway, as the building overheats with only a fraction of a degree over room temp. stored in the slab. A garage with large doors is a different story. Our loading bay (16' x 32', 20 ft ceiling and 14ft overhead door) is insulated and kept at 50F. With no air exchange required in that space by code, radiant actually makes sense. We have this area separately zoned.

The architects had originally proposed a refrigerant based heat transfer system which has the ability to take heat from one zone (cool) but dump the energy into another zone calling for heat. As is, our heating costs for 9500 square feet are less than my 1800 sq/ft home.

 

[theoldwizard1]

Plan on at R15+ in the floor and walls and R30+ in the ceiling.

It is possible to use a heat pump to heat water for a radiant heat floor in the winter and still blow cold air in the summer. A high efficiency, low temperature, inverter mini-split heat pump would work based on the attached temperature chart

What is the square footage on each level ? How many rooms on each level ?

 

[Legwound]

I should elaborate a little on the proposed building.

It'll likely be a pole barn or steel building.

I have yet to detemine width as I'm investigating the most cost effective roof truss and open span floor joist. For discussion sake I'll say 32 feet.

The building will either be a conventional peaked roof, in the neighborhood of 4/12 pitch.
or a shed type roof angled toward the south for solar gain (possible photo voltaic on roof, and/or evacuated tubes).

Inside will be 1000 ft sq of living space for myself and my wife. There will be an 1000 sq ft wood shop for my wifes furniture making. I have yet to decide if the shop will be over or under the living space. Both of these spaces will likely be 8" ceilings, and one space on top of the other. I like the idea of the shop above and using open web steel joices to support the shop above. This would make dust collection and running other services easy and efficient. We're not picky on viewing the services from below or possibly some sort of suspended ceiling.

The living space breakout would be 1-2 bedrooms, office, full bathroom, kitchen, diningroom, living room. As this is still even pre planning we're open to a few designs and would lean heavily towards a design that is more efficient over fancy configurations.

In addition there will be at least 100 sq ft space for mechanical work like welding cutting, fab and vehicle storage/maintenance. I'll have a lift and will need ceiling height to accomodate a full size van up in the air for servicing.

So there will be a two story section and another section that is open floor to roof truss with at least one truck door, if not two.

I was thinking slab on grade and radiant in the slab and had assumed radiant in the floor of the second floor section.

I was hoping for some solar input to the heat but recognize that some form of supplimental heat will be needed.

The building will be on grid for power (although I'd like to investigate a small photo voltaic battery back-up to run pumps, lights etc in the event of an extended power outage).

Electric for cooking, lighting and supplimental heat would keep external services easy and reduced initial capital outlay for running services but with a higher operating cost.

The areas I'm interested in locating will probably not have natural gas but propane is a consideration for supplimental heat, cooking, possible back-up generator fuel.

The wood shop and surrounding land could supply wood for a high efficiencty wood boiler (I'm thinking Garn or similar) for supplimental heat but does nothing for cooking etc.

From the above comments though it appears that a heat pump and some form of forced air for summer cooling. This then brings up geothermal as a supplimental heat input that would also serve as cooling input (heat extraction) for summer forced air cooling.

Additionally since this is a new build I could incorporate design elements to aid in natural summer convection to aid in cooling.

If the building is to be shed roofed I'd orient and slope the roof for maximum solar gain. I saw and have done some minor research on some buildings I saw on lake Erie that were shed roofed and completely covered with photo voltaic cells that mounted on standing rib steel roof sheets without any roof penetrations. In this case it was a ministry of transport building and the electity generated is sold onto the grid with a reversing meter.

I'd look into this as a revenue stream but I think the grants/programs are no longer very attractive. I would still consider this building configuration in the event programs change and a retrofit makes sense.

If i used this building style the high end of the roof would be the double story and I'd likely run the mechanical shop in a corridor along the low side of the building. I like this configuration and think it could lend itself to natural convective cooling up the roofline. This style of building would also be easier to span as the living space would be in the neighborhood of 24 feet wide. The longest span would then be the 24 foot with the mechanical shop corridor beside that for a shorter span.

Looking for ideas and experiences

oh and this would be in southern Ontario around the 49th parallel, which means pretty cold winters and humid summers.

 

[Legwound]

I thought I'd add some info I dug up on passive cooling.

I'm thinking that by incorporating as many passive elements as possible into my proposed building I will reduce my total cooling load requirements.

I'd really like to do without mechanical cooling and **** it up for the few summer days that are sweltering.

Anyway here's some interesting stuff I found.

http://www.yourhome.gov.au/passive-design/passive-cooling

I like the below ground tube idea. I could see some potential to use that as a combustion air supply for a boiler or other supplimental heat source for winter times as well as a potential supply for cooling air in hotter times of year.

http://milligansganderhillfarm.word...st-systemto-passivly-heat-and-cool-your-home/

I worked in a 1940's designed steel mill for a few years and had to do some work in the electric motor basement. The electric motor cooling was done via drawing air through wetted mesh. The mesh was very similar to the thin green pot scrubbers you use in your kitchen (no sponge). Water was applied with a low pressure fan style nozzle. There were dozens of 12" x 12" squres of the mesh, each with it's own nozzle. Latent heat of evaporation gave the cooling effect. I was down there in the dead of summer and I needed a parka. Big water consumption numbers but an interesting concept possibly scaled down and combined with an earth tube. I could see using rain collection and a large cistern coupled with a gravity fed nozzle/mesh arrangement for a small scale version.

More rambling thoughts.