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As we move toward residential buildings that contain 10 or more units each, I can’t help but think there has to be a better way to heat and cool the units than putting in a separate HVAC and hot water heater for each one.
We are trying to push the limits of thermal mass with the Gallery to minimize the need for heating and cooling, but we will still need hot water and a small HVAC assist!
There’s got to be a way to combine these things…
In this search for the holy grail of HVAC, I came across this awesome system that was apparently installed in Sac back in 1990. It uses a solar hot water system that supplies hot water and heating with gas backup in case the sun isn’t shining. Then it has a absorption chiller that can use the hot water energy to produce cold water that can cool the building (kind of mind-boggling, but just think of all the propane refrigerators in RVs that run on a similar concept). Of course the ideal house would have radiant floors that could run either the hot or cold water depending on the season and then the hot water too! Time for a field trip…
An alternative to the absorption chiller (which sounds a bit pie in the sky) may be geothermal. We just heard about a project on F St that uses geothermal to help heat and cool the units. A geothermal system may even be able to supply hot water by a “desuperheater.” It just seems a shame not to use all that sunshine we have!
Anyone have any other ideas out there?
UC Davis’s Energy Efficiency Center is helping establish a the Western Cooling Energy Center to showcase cutting edge HVAC technology, similar to its successful California Lighting Technology Center. Micah say’s it will be open in November… sounds like a field trip…
Steve
3 responses so far ↓
1 Steven // Aug 23, 2007 at 10:41 am
How ’bout using the box water heaters that they use in Europe and Asia? While it won’t be sufficient for everything in a unit (and only heat up water for the shower), it might make it feasible to use one giganto unit for everything else.
2 Micah // Aug 23, 2007 at 1:20 pm
Steve,
We have looked at using tankless water heaters for heating. The systems run slightly less efficiently than natural gas fired furnaces and cost substantially more. In order to use the tankless for hot water in showers and dishwashers and also for your heater you must put in mixing valves and upsize the tankless quite a bit. Now if you were to use it for radiant heating on its own system that would be a different approach. Although you would then need a separate system for cooling. We like this thinking. Thanks
3 Adam // Aug 23, 2007 at 4:59 pm
My favorite high efficiency cooling system I’ve seen so far was a roof pond with a super insulated floating block of foam over the top.
At night a pump sprays water onto the top of the block where it radiates its heat to the night sky and trickles back into the pond below through small holes in the foam. It’s not totally passive, but darn close.
The house is in Davis, but I couldn’t find a link on the internet: It’s the perfect mix of thermal mass and night cooling, which is perfect for our climate. No air conditioning, argon filled glass windows, super insulated walls, 2 stories, and the owners said their temperatures never rose to over 80.
Still, turning it into multi-family? I don’t know.
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