Just chill...

I haven't seen much on the blogfront in terms of HVAC and refrigeration since the Freeaire craze of last year (now installed in Killington, VT, where they estimate they're now saving more than 86,389 kilowatt hours of electricity, while eliminating an estimated 58 tons of global-warming CO2 emissions annually!!!), so I thought I might see what's on the horizon...

My search brought me to Ice Energy's Ice Bear, an amazingly simple concept with an equally simple installation procedure (off-the-shelf easy).

Similar to Freeaire, the Ice Bear utilizes cool air conditions to reduce power consumption. Whereas the Freeaire system requires frigid conditions to operate at maximum efficiency, the Ice Bear condenses and freezes water at night when energy consumption is less costly. It then holds the frozen water in an insulated storage tank until daytime when the weather warms.

As the warmer daytime temperatures engage the air conditioning, the refrigerant is forced through the coils in the stored ice and chilled before being pushed in to the building's HVAC ducts, thus providing a cool stream of efficiently refrigerated air.

The Ice Bear® 50 system has a capacity of 50 Ton hours of cooling, including 45 latent + sensible and an additional 5 sensible only. The unit provides 7.5 Tons of cooling capacity for 6 hours of continuous cooling.

Typical configurations:

-7.5 Ton for 6 hours
-5 Ton for 8 hours or more
-Offloading of 10 Ton rooftop unit, where 10 Ton unit is oversized due to high rooftop temperatures
-Offloading one stage of a 10, 15, or 20 Ton, 2-stage rooftop unit

There is also a residential unit capable of eliminating up to 95% of on-peak air conditioning demand. And as an added bonus:

Assists LEED certification

-Adds 3 or more points to the Energy and Atmosphere credits

-Contributes to Indoor Air Quality (IAQ) credits

-Brings Thermal Energy Storage (TES) enabling performance to refrigerant based air-conditioning projects

Now, since the Ice Bear claims to use an equal or lesser amount of energy --in addition to delivering a consistent capacity on 95+ degree days with no degradation in performance and no increase in power consumption-- I'm interested to see if this concept could be hacked to eliminate the majority of the power usage all together.

Consider a location like Kuwait that has an average January low of 45 degrees Fahrenheit and an average August high of 112 (the low for that month is a crisp 83 degrees)! With the exception of brown-outs caused by dust storms throughout June and July, I think it's safe to say that the area is drenched in sun.

So why not saturate the rooftop in solar, submerge the unit's storage containers underground to twice-insulate their exteriors from the harsh conditions,* and store the daytime energy in batteries for nightfall, using the saved energy to refreeze the cores at night?

*You're only depth-limited by accessibility...sink the parking 5-10 floors below the building and you could run the unit subterraneaously, making it even more efficient, but still accessible for repairs. Check some of the commercial case studies and decide for yourself. I think there are benefits that exceed the burden of peak consumption. I just don't have the book learnin' to prove it.

If there's grass on the roof...

Green roofs, while conceptually and environmentally brilliant, have been plagued with something we are all to familiar with in the Midwest: weight.

In most cases, the majority of existing buildings have the space, but can't afford the load weight. Or often times, the building can afford to hold the roofing system, but would crumble under an additional moisture load. Such added weight is even a problem with on sloping roof systems.

"...green roofs can retain as much as fifty to seventy percent of water that falls onto a roof. Retention varies according to climate. Hutchinson et al reported that a 10 to 12 cm vegetated roof in Portland, Oregon retained 69% of the total rainfall with peak flow reductions of 80% during a 15-month monitoring period. Investigations in East Lansing, Michigan cdompared a gravel roof and a vegetated roof with the mean percent rainfall retention ranging from 48.7% for a gravel roof to 82.8% for a vegetated roof. A similar range was seen on two roofs of different slopes in Goldsboro, North Carolina. Total rainfall retention was 55% for the sloped roof and 63% for the flat roof. Peak flow was reduced by 57% for the sloped roof and 87% for the flat roof." WEBSITE

Poundage-be-damned, green roofing companies are finally beginning to recognize that the existing market is far more available than the future market, and have consequently begun to reduce the load weight in their systems. On company that caught my eye is GreenTech, a Roswell, Georgia based company that specializes in athletic fields, landscpaing systems, golf course systems, and yes, green roof systems.


They're no newcomer to the game, though. In addition to laying claim to New York's largest greenroof and the grass at Wimbledon, GreenTech has found a way to box out the weight and open up the lane to a lighter, newer, more accessible green roof.

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From their website:

The GreenTech Roof Garden System weighs less than comparable systems for a couple reasons. Forklift and drainage channels displace soil with air. But more importantly, no drainage medium (gravel) is required in the system. This feature works to reduce weight of the system as well as cost of materials and labor.

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So why is this system able to shed the pounds?

The system has built-in drainage channels that allow the water to flow through the soil into open channels and directly to roof drain outlets. At the same time, each high-density polyethylene module protects the roof surface from root infiltration and damage to the roof membrane. The result is a large planting surface -- with the all-important root depth -- that's more lightweight and flexible than other green roofs. Given the fact that it still discharges the water, some might view the system as less than substantial as other systems, but it needs to be kept in mind that the grey water discharge can be stored for landscape use.

Additionally, the GreenTech allows for almost 40 times the drainage and air flow capacity of conventional drainage systems. Even the drainage channels displace soil, resulting in a 20 to 40% weight reduction. You can even remove the individual sections to replace, repair, or modify the existing system.

But this is what I like most:

The system can be installed in very unlikely places. A back patio loft in the city can suddenly transform into a mini Central Park. You drop the crates, fill with dirt, cover with sod, and finish the edge (simplified, yes, but it is undoubtedly FAR MORE basic than most systems on the market). I like.